![Effect of human UII on inositol phosphate turnover and intracellular calcium concentration ([Ca 2+ ] i ) in human UT-transfected CHO cells. (A) In cells labeled with [ 3 H]inositol, graded concentrations of UII, in the presence of Li block, induces a dose-dependent increase of inositol phosphate (IPx) formation. DPM, disintegrations per minute. (B) Time course effect of UII (100 nM, black bar) on [Ca 2+ ] i in Fura 2-loaded cells. In the presence of extracellular Ca 2+ , a biphasic response in observed, i.e., a peak originating from intracellular calcium stores (as a consequence of IP formation) and a plateau phase caused by an entry of extracellular Ca 2+. In the absence of extracellular Ca 2+ , the response is monophasic with the plateau-phase missing. (C) Effect of graded concentrations of UII on the peak [Ca 2+ ] i response. [Reprinted from McDonald et al. (2007). Used with permission.]](https://www.researchgate.net/profile/David-Vaudry/publication/269999047/figure/fig4/AS:614022923698179@1523405881550/Effect-of-human-UII-on-inositol-phosphate-turnover-and-intracellular-calcium_Q320.jpg)
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1521-0081/67/1/214–258$25.00 http://dx.doi.org/10.1124/pr.114.009480
PHARMACOLOGICAL REVIEWS Pharmacol Rev 67:214–258, January 2015
Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics
ASSOCIATE EDITOR: DAVID R. SIBLEY
International Union of Basic and Clinical
Pharmacology. XCII. Urotensin II, Urotensin
II–Related Peptide, and Their Receptor: From
Structure to Function
Hubert Vaudry, Jérôme Leprince, David Chatenet, Alain Fournier, David G. Lambert, Jean-Claude Le Mével, Eliot H. Ohlstein,
Adel Schwertani, Hervé Tostivint, and David Vaudry
Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan,
France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-
Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of
Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical
Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester,
United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l’Information
Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals,
Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec,
Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations
Endocriniennes, Muséum National d’Histoire Naturelle, Paris, France (H.T.)
Abstract. ....................................................................................215
I. Introduction. . . ..............................................................................215
II. Urotensin II. . . ..............................................................................216
A. Discovery of Urotensin II in Fish . . ......................................................216
B. Discovery of Urotensin II in Mammals . . . ................................................216
C. Discovery of Urotensin II–Related Peptide ...............................................219
D. Secondary Structure of Urotensin II and Urotensin II–Related Peptide ...................219
E. Structure of the Urotensin II and Urotensin II–Related Peptide Precursors and
Post-Translational Processing............................................................219
F. The Urotensin II and Urotensin II–Related Peptide Genes ...............................221
G. Distribution of Urotensin II and Urotensin II–Related Peptide in the Central Nervous System . 221
H. Distribution of Urotensin II and Urotensin II–Related Peptide in Peripheral Organs ......222
I. Urotensin II and Urotensin II–Related Peptide in Tumor Cells . . .........................223
J. Phylogenetic Evolution of Urotensin II . . . ................................................223
1. Discovery of Two Novel Urotensin II–Related Peptide-Like Genes in Teleosts. . . .......223
2. Origin and Evolution of the Urotensin II Gene Family in Vertebrates. .................224
3. Evolutionary Relationships between Peptides of the Urotensin II and
Somatostatin Families. . . . ............................................................224
III. The Urotensin II Receptor . ..................................................................225
A. Cloning and Characterization of Urotensin II Receptor ...................................225
B. Signaling Mechanisms . ..................................................................227
C. Structure-Activity Relationships . . . ......................................................229
D. Design of Nonpeptidic Urotensin II Receptor Agonists and Antagonists ...................232
E. Distribution of Urotensin II Receptor in the Central Nervous System . . ...................234
This work was supported by grants from the Institut National de la Santé et de la Recherche Médicale (INSERM, U982); the European
Regional Development Fund (project PeReNE); an INSERM-Fonds de la Recherche en Santé du Québec exchange program (to A.F. and D.V.);
the British Heart Foundation and British Journal of Anaesthesia (to D.G.L.); and the Région Haute-Normandie (to H.V., J.L., and D.V.).
Address correspondence to: Dr. Hubert Vaudry, Institut National de la Santé et de la Recherche Médicale U982, Institute for Research
and Innovation in Biomedicine, International Associated Laboratory Samuel de Champlain, University of Rouen, 76821 Mont-Saint-Aignan,
France. E-mail: hubert.vaudry@univ-rouen.fr
D.V. and H.V. are Affiliated Professors at the Institut National de la Recherche Scientifique–Institut Armand-Frappier.
dx.doi.org/10.1124/pr.114.009480.
214
by guest on December 29, 2014pharmrev.aspetjournals.orgDownloaded from
F. Distribution of Urotensin II Receptor in Peripheral Organs ...............................238
G. Urotensin II Receptor in Tumor Cells ....................................................238
H. Phylogenetic Evolution of Urotensin II Receptor..........................................239
IV. Biologic and Pharmacologic Effects of Urotensin II and Urotensin II–Related Peptide . . .......239
A. Effects of Urotensin II/Urotensin II–Related Peptide in the Central Nervous System ......239
1. Action on Rapid Eye Movement Sleep. ................................................239
2. Action on Food Intake and Energy Homeostasis. . .....................................240
3. Action on Cardiovascular Activity. ....................................................241
4. Action on Locomotor Activity.. . . ......................................................241
5. Action on Anxiety and Depression.....................................................241
6. Action on Ventilation. ................................................................242
7. Neuroendocrine Actions. . . ............................................................242
B. Effect of Urotensin II/Urotensin II–Related Peptide on the Cardiovascular System . .......244
1. Remodeling of Vas cular Tissue. . ......................................................244
2. Regulation of Vascular Tone. . . . ......................................................244
3. Regulation of Myocardial Contractility. ...............................................246
4. Role in Hypertension. ................................................................246
5. Role in Atherosclerosis.. . . ............................................................246
6. Role in Heart Failure. ................................................................247
C. Effect of Urotensin II/Urotensin II–Related Peptide on the Urogenital Tract . .............248
D. Effect of Urotensin II/Urotensin II–Related Peptide on the Gastrointestinal Tract . . .......248
E. Effect of Urotensin II/Urotensin II–Related Peptide on the Pancreas. . . ...................249
F. Effect of Urotensin II/Urotensin II–Related Peptide on the Liver .........................250
G. Effect of Urotensin II/Urotensin II–Related Peptide on the Adrenal Gland . . . .............250
V. Conclusions and Perspectives ................................................................250
Acknowledgments . . . ........................................................................251
References ..................................................................................251
Abstract——Urotensin II (UII) is a cyclic neuropeptide
that was first isolated from the urophysis of teleost fish
on the basis of its ability to contract the hindgut. Sub-
sequently, UII was characterized in tetrapods including
humans. Phylogenetic studies and synteny analysis in-
dicate that UII and its paralogous peptide urotensin
II-related peptide (URP) belong to the somatostatin/
cortistatin superfamily. In mammals, the UII and URP
genes are primarily expressed in cholinergic neurons
of the brainstem and spinal cord. UII and URP mRNAs
are also present in various organs notably in the
cardiovascular, renal, and endocrine systems. UII and
URP activate a common G protein–coupled receptor,
called UT, that exhibits relatively high sequence identity
with somatostatin, opioid, and galanin receptors. The UT
gene is widely expressed in the central nervous system
(CNS) and in peripheral tissues including the retina,
heart, vascular bed, lung, kidney, adrenal medulla, and
skeletal muscle. Structure-activity relationship studies
and NMR conformational analysis have led to the rational
design of a number of peptidic and nonpeptidic UT
agonists and antagonists. Consistent with the wide
distribution of UT, UII has now been shown to exert
a large array of biologic activities, in particular in the
CNS, the cardiovascular system, and the kidney. Here,
we review the current knowledge concerning the
pleiotropic actions of UII and discusses the possible use
of antagonists for future therapeutic applications.
I. Introduction
In 1980, Howard Bern and his coworkers published
an article, now a citation classic, in which they reported
the characterization of a novel regulatory peptide from
the fish urophysis that they called urotensin II (UII)
(Pearson et al., 1980). Because the urophysis is a
neurohemal organ that is exclusively present in teleosts
(Bern et al., 1985), it had long been thought that UII
only existed in fish. However, subsequent studies have
led to the identification of UII orthologs in amphibians
(Conlon et al., 1992b) and mammals, including humans
(Coulouarn et al., 1998). Soon after, a UII receptor was
ABBREVIATIONS: ACAT-1, acyltransferase-1; ACTH, adrenocorticotropin; CHF, congestive heart failure; CHO, Chinese hamster ovary;
CNS, central nervous system; CSF, cerebrospinal fluid; CTF-prohUII, C-terminal fragment of human pro-UII; 3D, three-dimensional; ECL,
extracellular loop; FLIPR, fluorometric imaging plate reader; GPCR, G protein–coupled receptor; HCC, human corpus cavernosum; HPLC,
high-performance liquid chromatography; HTS, high-throughput screening; IP
3
, inositol-1-4-5 triphosphate; LDL, low-density lipoprotein;
MAPK, mitogen-activated protein kinase; NO, nitric oxide; PLC, phospholipase C; PPT, pedunculopontine tegmental nucleus; 2R, two whole-
duplication rounds; REM, rapid eye movement; ROS, reactive oxygen species; RT-PCR, reverse-transcription polymerase chain reaction; SHR,
spontaneously hypertensive rats; SNPs, single nucleotide polymorphisms; T2DM, type 2 diabetes mellitus; UCA, urocontrin A; UII, urotensin II;
URP, urotensin II–related peptide; UT, UII receptor; WKY, Wistar-Kyoto rats.
Urotensin II and Its Receptor 215
identified, called UT, which is widely expressed in the
central nervous system (CNS) and in various peripheral
organs, notably in the cardiovascular system and in
the kidney (Ames et al., 1999; Liu et al., 1999; Mori
et al., 1999; Nothacker et al., 1999). More recently, the
existence of a UII paralog called urotensin II–related
peptide (URP) was characterized in the brain of rodents
(Sugo et al., 2003). Consistent with the widespread
distribution of UT, it has been shown that UII exerts
a number of biologic effects including regulation of
behaviors and neuroendocrine activities, as well as
central and peripheral control of blood pressure and
heart rate (Douglas et al., 2004a; Vaudry et al., 2010).
Clinical studies have provided evidence that UII and
UT are implicated in various pathologies, including
cardiovascular diseases (Douglas et al., 2002; Ng et al.,
2002; Richards et al., 2002; You et al., 2012; Watson
et al., 2013), renal diseases (Totsune et al., 2001), and
diabetes (Wenyi et al., 2003; Sidharta et al., 2009). The
various activities of UII and the potential implication of
the urotensinergic system in various pathologies have
prompted academic laboratories and pharmaceutical
companies to design specific agonists and antagonists
that are currently used for basic research and may
lead to therapeutic applications (Leprince et al., 2008;
Maryanoff and Kinney, 2010; Tsoukas et al., 2011;
Merlino et al., 2013).
II. Urotensin II
A. Discovery of Urotensin II in Fish
Teleost fish possess a singular neurosecretory system
located in the caudal region of the spinal cord. This
system consists of two rows of magnocellular secretory
neurons, termed Dahlgren cells (Dahlgren, 1914), sym-
metrically arranged in the ventral horn of the spinal cord,
that project their axons into a neurohemal organ called
the urophysis (Enami, 1959). The caudal neurosecretory
system of teleosts is thus anatomically and function-
ally similar to the hypothalamo-neurohypophysial neuro-
secretory system (Bern et al., 1985; McCrohan et al.,
2007).
Early studies have shown that urophysial extracts
contain substances that exhibit various pharmacological
activities both in fish and in mammals (Chan, 1975). Two
laboratories have concurrently undertaken the purifica-
tion and isolation of the bioactive peptides, collectively
named urotensins, that are responsible for the observed
pharmacologic effects. Thus, the group of Karl Lederis
characterized urotensin I, a 41-amino acid peptide
from an extract of the urophysis of the white sucker
Catostomus commersonii (Lederis et al., 1982), that was
found to be a paralog of corticotropin-releasing hormone
(Vale et al., 1981), while the group of Howard Bern
characterizedUII,a12-aminoacidpeptide,froman
extract of the urophysis of the goby Gillichthys mirabilis
(Pearson et al., 1980), that was found to exhibit some
structural similarity to somatostatin (Brazeau et al.,
1973).
The sequence of UII has been relatively well preserved
in all fish species studied (Vaudry et al., 2010), suggesting
that the peptide exerts important biologic functions. As
a matter of fact, in fish, UII induces a general spasmo-
genic activity that has been documented in various tis-
sue preparations including the trout (Salmo gairdneri)
urinary bladder, the trout posterior intestine, the guppy
(Poecilia reticulata) oviduct, the goby sperm duct, the eel
(Anguilla rostrata) caudal lymph heart (Bern et al., 1985),
and the dogfish (Scyliorhinus canicula) vascular ring
(Hazon et al., 1993). In unanesthetized trout (Oncorhynchus
mykiss), intra-arterial administration of UII causes an
increase in aortic blood pressure and a decrease in heart
rate (Le Mével et al., 2008). In fish, UII also contributes
to the control of hydromineral balance through a direct
action on ion transport across the skin, gill, intestine,
and urinary bladder (Marshall, and Bern, 1979, 1981;
Loretz and Bern, 1981; Loretz et al., 1982, 1983, 1985;
Mainoya and Bern, 1982, 1984; Lu et al., 2008). Finally,
UII participates in the neuroendocrine regulation of
prolactin secretion in tilapia (Oreochromics mossambicus;
Grau et al., 1982; Rivas et al., 1986) and cortisol se-
cretion in the trout (Arnold-Reed and Balment, 1994)
and the European flounder (Platichtys flesus;Kelsall
and Balment, 1998).
B. Discovery of Urotensin II in Mammals
Because the urophysis is a neurosecretory organ that
is exclusively found in teleosts, it has long been thought
that UII was present only in fish and not in other
vertebrates. Surprisingly however, biochemical experi-
ments have shown the occurrence of specific binding
sites for goby UII in rat arteries (Itoh et al., 1987, 1988),
and pharmacological studies have revealed that fish UII
exerts various effects in mammals such as relaxation of
the mouse anococcygeus muscle (Gibson et al., 1984)
and endothelium-independent contraction of the rat
aorta (Gibson, 1987). Goby UII also induces a marked
increase of intracellular calcium concentration ([Ca
2+
]
i
)
in rat aorta cells (Gibson et al., 1988). The observation
that fish UII possessed significant biologic activity in
rodents strongly suggested that an homologous peptide
might exist in mammals. In fact, immunohistochemical
studies have shown the presence of UII-immunoreactive
neurons in the brain and anterior spinal cord of fish
(Yulis and Lederis, 1986, 1988), indicating that UII could
be produced not only in the caudal neurosecretory organ
but also in extra-urophysial neurons.
The first unequivocal evidence for the occurrence of
UII in tetrapods was provided by the purification of
a UII-immunoreactive peptide from an extract of the
whole brain of the European green frog Rana ridibunda
(Conlon et al., 1992b), now renamed Pelophylax ridi-
bundus (Conlon et al., 2009). Structural characterization
of the isolated peptide showed that frog UII encompasses
216 Vaudry et al.
13 amino acids (Conlon et al., 1992b) instead of 12 amino
acids as in all fish UII sequences identified to date
(Lihrmann et al., 2013). However, the cyclic region that
is essential for the biologic activity of the peptide (Itoh
et al., 1987) is identical in fish and amphibian sequences
(Fig. 1). Unlike many other neuropeptides, UII is not
found in hypothalamic neurons, but is almost exclusively
produced in motoneurons of the frog brainstem and
spinal cord (Chartrel et al., 1996). The identification of
UII in the frog brain confirmed that 1) UII is produced in
extra-urophysial nervous tissues and 2) urotensinergic
systems exist in vertebrate phyla outside the fish lineage
(Conlon et al., 1997; Conlon, 2008; Vaudry et al., 2010).
This finding thus paved the way for the discovery of UII
and its receptor in mammals.
The cDNA encoding the UII precursor has been
cloned from a frog brain library (Coulouarn et al.,
1998). Frog UII cDNA has then been used to identify
an expressed sequence tag from bulk human colon
tumors and subsequently to clone the human prepro-
UII cDNA (Coulouarn et al., 1998). The existence of
a Lys-Lys-Arg cleavage motif in the C-terminal region
of the precursor (see section II.E) predicts that human
UII is an 11-amino acid peptide with a cyclic hexapeptide
motif (Cys-Phe-Trp-Lys-Tyr-Cys) identical to that of fish
andfrogUII(Fig.2,compound1), explaining why fish
UII can excite mammalian UT (Gibson et al., 1984, 1988;
Gibson, 1987). Characterization of the cDNAs encoding
the rat, mouse (Coulouarn et al., 1999) and porcine
prepro-UII (Mori et al., 1999) rapidly ensued. The way
UII was identified in mammals is thus a remarkable
illustration of the power of the comparative approach for
the discovery of novel human neuropeptides (Conlon,
2000). Of note, urotensin I, the other regulatory peptide
initially characterized from the fish urophysis (Lederis
et al., 1982), led to the discovery of the urocortin peptides
(Vaughan et al., 1995). Other mammalian neuropeptides
characterized through a similar comparative strategy
are: melanin-concentrating hormone (Kawauchi et al.,
1983; Vaughan et al., 1989), cortistatin (Vaudry et al.,
1992; de Lecea et al., 1996), secretoneurin (Vaudry and
Conlon, 1991; Kirchmair et al., 1993), gonadotropin-
inhibitory hormone (Tsutsui et al., 2000; Kriegsfeld
et al., 2006), 26RFa/QRFP (Chartrel et al., 2003), and
adrenomedullin 2 (Takei et al., 2004a,b).
The amino acid sequence of UII has now been
determined in a number of vertebrate species from
lamprey to human (Fig. 1). As shown in Fig. 1, the
Fig. 1. Alignment of UII and URP sequences. The conserved cyclic hexapeptide is indicated in bold characters.
Urotensin II and Its Receptor 217
sequence of the N-terminal region of UII is quite
variable, and the predicted length of the peptide ranges
from 11 amino acids for human UII to 17 amino acids
for mouse UII. In contrast, the primary structure of the
cyclic hexapeptide has been totally preserved from fish
to mammals. Immunohistochemical studies had long
suggested the existence of UII-like peptides in the CNS
of the marine mollusc Aplysia californica (González et al.,
Fig. 1. Continued.
218 Vaudry et al.
1992) and, recently, a peptide exhibiting structural sim-
ilarity to vertebrate UII has been characterized in this
gastropod (Romanova et al., 2012), suggesting that a
urotensinergic system may also exist in protostomes
(see section II.J.3).
C. Discovery of Urotensin II–Related Peptide
By combining high-performance liquid chromatogra-
phy (HPLC) analysis with radioimmunoassay detection,
Sugo et al. (2003) have isolated from a rat brain extract,
an 8-amino-acid peptide that they named URP (Fig. 2,
compound 2). The primary structure of URP is highly
similar to that of the C-terminal octapeptide region of
UII. The sequence of URP has now been determined in
representative species of teleost fish (Quan et al., 2012),
amphibians (Konno et al., 2013), birds (Tostivint et al.,
2006), and mammals (Dubessy et al., 2008), and it ap-
pears that the structure of the peptide has been strongly
preserved during vertebrate evolution (Vaudry et al.,
2010). As for UII, the sequence of the cyclic hexapeptide
of URP is identical in all species investigated so far
(Fig. 1).
D. Secondary Structure of Urotensin II and Urotensin
II–Related Peptide
Conformational analysis of goby (Bhaskaran et al.,
1994) and human (Flohr et al., 2002; Lescot et al., 2007)
UII and human URP (Chatenet et al., 2004) in solution
has been determined by nuclear magnetic resonance
spectroscopy and restrained molecular dynamics. The
solution structure of the cyclic UII hexapeptide is well-
defined, whereas the flanking linear segments appear to
be flexible (Bhaskaran et al., 1994; Flohr et al., 2002;
Lescot et al., 2007). However, no canonical turn motifs
involving intramolecular hydrogen bonds are observed
in the cyclic part of goby and human UII at 300 K
(Bhaskaran et al., 1994; Flohr et al., 2002). At a lower
temperature (280 K), the hydrogen/deuterium exchange
time of the amide protons of residues Tyr
9
and Cys
10
is
longer than that of the other amide protons, suggesting
the presence of a local stabilized structure (Lescot et al.,
2007). The optimal proximity between the NH of Tyr
9
and the carbonyl group of Trp
7
and between the amide
proton of Cys
10
and the C=O moiety of Lys
8
in com-
bination with the (w,c) dihedral angle values indicates
the occurrence of a distended inverse g-turn centered on
Lys
8
together with a standard inverse g-turn centered
on Tyr
9
(Lescot et al., 2007). In sodium dodecylsulfate
micelles used as a membrane mimetic environment,
human UII exhibits two distinct conformations that ex-
change slowly at 300 K, i.e., a major population that
encompasses an unprecedented type II9b-hairpin motif
duetothepresenceofab-turn from Phe
6
to Tyr
9
and
a minor population of random structures (Carotenuto
et al., 2004a). Identification of the structural character-
istics of UII in water at 280 K or in a membrane-like
environment has served as conformational templates to
generate three-dimensional three-point pharmacophores
(Flohr et al., 2002; Carotenuto et al., 2004a; Lescot et al.,
2007) for virtual screening of small-molecule libraries or
ligand-based drug design (see section IV.A) .
Nuclear Overhauser effect observed between the
amide proton of Tyr
6
and the Hbof Trp
4
and the (w,c)
dihedral angle values reveal that, in water, the structure
of URP at 280 K consists of an inverse g-turn that
extends from Trp
4
to Tyr
6
(Chatenetetal.,2004).In
very much the same way as for human UII (Lescot et al.,
2007), all the side-chains adopt a preferential orienta-
tion, and URP presents a hydrophobic surface formed
by the Phe
3
,Trp
4
,Tyr
6
, and Val
8
residues (Chatenet
et al., 2004). The main difference between the solution
structures of human UII and URP lies in the important
variation in the position of the lysine side-chain (Lescot
et al., 2007).
E. Structure of the Urotensin II and Urotensin
II–Related Peptide Precursors and
Post-Translational Processing
The cDNAs encoding the UII and URP precursors
have been characterized in a number of vertebrate
Fig. 2. Chemical structures of human urotensin II (compound 1) and mammalian URP (compound 2).
Urotensin II and Its Receptor 219
species from fish to mammals (Ohsako et al., 1986;
Coulouarn et al., 1998; Vaudry et al., 2010) (Fig. 1). In
all species, UII and URP precursors exhibit a similar
organization with a predicted 19- to 28-amino-acid signal
peptide (Petersen et al., 2011) and a 78 to 127 amino
acid N-terminal flanking peptide, the UII or URP
bioactive sequence being located at the C-terminal
extremity of the precursor (Fig. 3). However, compar-
ison of the cDNA sequences of, e.g., human (Coulouarn
et al., 1998), porcine (Mori et al., 1999), mouse
(Coulouarn et al., 1999; Elshourbagy et al., 2002), and
carp prepro-UII (Ohsako et al., 1986) reveals that the
dibasic motifs that constitute potential cleavage sites by
prohormone convertases (Artenstein and Opal, 2011;
Seidah et al., 2013) have been poorly conserved. For
instance, in human, the existence of a Lys
91
-Lys
92
-Arg
93
tribasic motif (Coulouarn et al., 1998) suggests that the
UII precursor can produce an 11-residue form of UII. In
the mouse precursor, this cleavage site does not exist
and processing is thought to occur at the Arg
105
-Lys
106
dibasic site (Coulouarn et al., 1999), thus generating
a 17-residue mature form of UII (Fig. 1). In the case of
the URP precursor, a Lys-Arg canonical cleavage motif
has been strongly preserved from fish to mammals
(Coulouarn et al., 1998; Lu et al., 2006) so that the con-
served cyclic hexapeptide is flanked at its N-terminal
position by a single residue (Figs. 1 and 2).
Porcine kidney tissue exhibits urotensin II-converting
enzyme activity as shown by a mass spectrometry-
assisted enzyme-screening system (Schlüter et al., 2003).
Incubation of a 25-amino-acid C-terminal fragment of
human pro-UII (CTF-prohUII) with recombinant furin
givesrisetoamature11-aminoacidformofUII(Russell
et al., 2004). Permeabilized epicardial mesothelial cells
can also process CTF-prohUII to generate human UII,
and conversion of CTF-prohUII to human UII is reduced
in conditions known to inhibit furin activity (Russell
et al., 2004). These observations provide evidence for the
existence of intracellular furin-like urotensin II–converting
enzyme activity in human epicardial mesothelial cells.
The amino acid sequence of UII has been determined
in dogfish (Conlon et al., 1992a), flounder (Conlon et al.,
1990), frog (Conlon et al., 1992b), and pig (Mori et al.,
1999) confirming that the peptide is generated through
cleavage at the Arg
115
-Lys
116
-Arg
117
site of the flounder
precursor (Lu et al., 2006), at the Lys
112
-Lys
113
-Arg
114
Fig. 3. Structure of the human prepro-UII and prepro-URP genes. (A) The prepro-UII gene comprises five exons and encodes two precursor isoforms
(variants a and b) that only differ at their N-terminal extremity, the UII sequence being located at the C-terminal extremity. Each isoform generates
the same mature UII peptide through proteolytic cleavage at a tribasic site (KKR). (B) The prepro-URP gene comprises five exons. The URP sequence is
located at the C-terminal extremity of the URP precursor and the mature peptide is generated by proteolytic cleavage at a dibasic site (KR). SP, signal
peptide; ATG/AUG, initiation codon; Stop, termination codon. (Adapted from Lihrmann et al., 2013.)
220 Vaudry et al.
site of the frog precursor (Coulouarn et al., 1998), and at
the Lys
107
-Lys
108
-Arg
109
site of the porcine precursor
(Mori et al., 1999). HPLC analysis of human brainstem
and spinal cord extracts has revealed that the major
UII-immunoreactive peptide coelutes with synthetic
11-residue human UII (Chartrel et al., 2004), whereas
in mouse brain extracts it coelutes with synthetic
17-residue mouse UII (Dubessy et al., 2008). These
findings strongly suggest that endoproteolytic processing
occurs at the Lys
91
-Lys
92
-Arg
93
site of the human UII
precursor and at the Arg
105
-Lys
106
site of the mouse UII
precursor.
To date, the amino acid sequence of the URP peptide
has only been determined in rat (Sugo et al., 2003). In
that case, cleavage of the precursor occurs at a Lys
109
-
Arg
110
site (Sugo et al., 2003). The strong conservation
of this dibasic site across vertebrate species supports
the notion that all URP precursors undergo similar
endoproteolytic cleavage.
F. The Urotensin II and Urotensin II–Related
Peptide Genes
Inhuman,thegeneencodingtheUIIprecursor,also
named uts2, is composed of five exons. Two distinct
precursor isoforms with 139 (isoform a) and 124 (isoform b)
amino acids have been characterized that likely result
from alternative initiation at two distinct AUG codons
(Coulouarn et al., 1998; Ames et al., 1999; Lihrmann
et al., 2013). These two isoforms only differ in their
N-terminal extremity and thus give rise to the same
mature UII peptide, the coding sequence of UII being
located in the last exon. In all other vertebrate species
studied so far (mouse, rat, pig, monkey, chicken, and
zebrafish), only isoform b has been identified. In the
zebrafish Danio rerio, two UII genes, UIIaand UIIb,
that exhibit the same organization, have been identified
(Tostivint et al., 2006). The uts2d gene encoding the
prepro-URP comprises five exons in all vertebrate spe-
cies examined. In tetrapods, the coding sequence of
URP is located in the fifth exon (Lihrmann et al., 2013),
whereas, in teleosts, it is split between exons 4 and 5
(Quan et al., 2012). As mentioned above (see section II.J),
two additional paralogous genes of the UII family have
been characterized in actinopterygians and sarcopterygians
and have been called URP1 and URP2 (Nobata et al.,
2011; Tostivint et al., 2013, 2014). In zebrafish, both
URP1 and URP2 genes contain five exons and, for each
gene, the coding sequence of the mature peptide is located
on the last exon (Parmentier et al., 2011).
G. Distribution of Urotensin II and Urotensin
II–Related Peptide in the Central Nervous System
UII was initially isolated and characterized from the
urophysis of teleost fish (Pearson et al., 1980). The axon
terminals releasing UII into the urophysis originate
from Dahlgren cells, i.e., large cholinergic neurons that
are located in the caudal region of the ventral horn of
the spinal cord of teleosts (Enami, 1959). Immunohis-
tochemical labeling has confirmed that UII is primarily
located in neurosecretory cells of the ventral spinal cord
(Owada et al., 1985; Oka et al., 1989; Parmentier et al.,
2006). However, subsequent studies have shown that
UII is also present in the fish brain (Waugh and Conlon,
1993), and the expression of UII mRNA in fish brain
has been confirmed by reverse-transcription polymerase
chain reaction (RT-PCR; Lu et al., 2006; Sun et al.,
2014). In various species of freshwater and seawater
fish, UII is found in cerebrospinal fluid (CSF)–contacting
neurons located within the ventral ependyma bordering
the central canal along the entire length of the spinal
cord and medulla (Yulis and Lederis 1986, 1988). These
UII-containing neurons project their axons toward the
external surface of the spinal cord, and ascending fibers
innervate various regions of the brain (Yulis and Lederis,
1986, 1988). Although nonteleost fish do not possess an
authentic urophysis, they do exhibit a neurohemal area
apposed to the ventral spinal cord that extends along
several spinal cord segments (Fridberg and Bern, 1968).
UII-immunoreactive cell bodies actually occur in the caudal
spinal cord of representative species of nonteleost fish,
including chondrichthyes (cartilaginous fish) and dipnoans
(lungfish) but not agnatha (jawless fish) (Onstott and
Elde, 1986).
In the CNS of tetrapods, UII is primarily expressed in
motoneurons of the brainstem and spinal cord. Specif-
ically, in the European green frog, UII immunoreactiv-
ity is found in neurons of the hypoglossal nucleus of the
medulla oblongata, which controls tongue muscles, and
in a subpopulation of motoneurons of the spinal cord,
particularly abundant in the caudal region (Chartrel
et al., 1996). In the brain of rodents, UII is primarily
expressed in brainstem nuclei including the dorsal
motor nucleus of the vagus, the hypoglossal nucleus,
the trigeminal motor nucleus, the facial motor nucleus,
the abducens nucleus, and the trigeminal motor nucleus
(Coulouarn et al., 1999; Dun et al., 2001; Dubessy et al.,
2008). Although the expression pattern of URP largely
overlaps with that of UII, differential levels of expres-
sion occur in most brainstem nuclei. For instance, the
expression of URP is substantially higher than that of
UII in the abducens nucleus, the dorsal motor nucleus of
the vagus, the Edinger-Westphal nucleus, the locus
coerulus, the lateral superior olive, the raphe obscursus
nucleus, the reticular nucleus, and the paragigantocel-
lular nucleus (Dubessy et al., 2008). Reciprocally, the
UII gene, but not the URP gene, is expressed in the
medial vestibular nucleus (Dubessy et al., 2008). In
mouse and rat, UII is expressed in a subset of spinal
motoneurons, the density of UII-positive neurons being
higher in the lumbar and sacral regions than in the
cervical segment (Coulouarn et al., 1998, 1999; Ames
et al., 1999; Dun et al., 2001; Pelletier et al., 2002, 2005;
Egginger et al., 2006; Dubessy et al., 2008). A majority of
mouse spinal motoneurons simultaneously express UII
Urotensin II and Its Receptor 221
andURPmRNAsaswellasandrogenreceptormRNA
(Pelletier et al., 2005). Similarly, a vast majority of rat
motoneurons that express UII mRNA are also androgen
receptor immunopositive (Pelletier et al., 2002). Consis-
tent with these observations, in mouse and rat, andro-
gens downregulate UII and/or URP gene expression most
likely through a direct action at the level of motoneurons
(Pelletier et al., 2002, 2005). Developmental studies show
that UII mRNA is expressed in the rat spinal cord as
early as embryonic day 10, i.e., during terminal mitosis of
motoneurons (Phelps et al., 1988; Chen and Chiu, 1992),
suggesting that UII could play a role in motoneuron
differentiation, survival, and/or programmed cell death
(Coulouarn et al., 2001). In human, UII-immunoreactive
material is present in both the brainstem and spinal cord
(Chartrel et al., 2004). In the human spinal cord, UII is
contained in a subpopulation of ventral horn motoneur-
ons (Chartrel et al., 2004).
H. Distribution of Urotensin II and Urotensin
II–Related Peptide in Peripheral Organs
In mammals, early studies have shown that the UII
gene is widely expressed outside the CNS, notably
in the cardiovascular, renal, and endocrine systems
(Coulouarn et al., 1998; Ames et al., 1999; Matsushita
et al., 2001; Douglas et al., 2002; Dschietzig et al., 2002;
Elshourbagy et al., 2002). It was subsequently found
that URP mRNA is also present in various organs and
that, in peripheral tissues as in the CNS, the UII and
URP genes are differentially expressed (Sugo et al.,
2003; Dubessy et al., 2008). For instance, in mouse,
whereas the UII and URP genes are equally expressed
in skeletal muscle, UII expression predominates in the
vagina, uterus, and testis, and inversely, only URP ex-
pression occurs in the thymus, heart, colon, and seminal
vesicles (Dubessy et al., 2008). Measurement of the
arteriovenous gradient of UII/URP concentration in
sheep indicates that the heart, liver, and kidney re-
lease UII and/or URP in the circulation (Charles et al.,
2005).
In the cardiovascular system, UII mRNA is expressed
in vascular smooth muscle cells (Douglas et al., 2002),
endothelial cells (Totsune et al., 2003; McDonald et al.,
2007), and cardiac fibroblasts (Tzanidis et al., 2003). In
the human heart, UII mRNA is found in the right
atrium and ventricular septum (Matsushita et al., 2001).
UII and URP levels are upregulated in various cardio-
vascular diseases, including systemic and pulmonary
hypertension, atherosclerosis, and congestive heart
failure. In particular, UII and URP mRNA expression
is higher in the atrium of spontaneously hypertensive
rats (SHR) compared with age-matched Wistar-Kyoto
rats (WKY) (Hirose et al., 2009). In human, plasma
UII/URP is significantly elevated in congestive heart
failure (Ng et al., 2002; Richards et al., 2002; Russell
et al., 2003; Russell, 2008). Although in patients with
acute heart failure both plasma UII and URP levels
are elevated, URP concentrations are 10-fold higher
than those of UII (Jani et al., 2013). To date, little is
known regarding the regulatory mechanisms underly-
ing overexpression of UII and/or URP in cardiovascular
disease.
The renal system is another important site of UII
production. UII and URP mRNAs are present in the
human kidney (Coulouarn et al., 1998; Nothacker et al.,
1999; Matsushita et al., 2001; Totsune et al., 2001, 2003;
Sugo et al., 2003) but are virtually absent in the kidney
of monkey (Elshourbagy et al., 2002), rat (Sugo et al.,
2003), and mouse (Elshourbagy et al., 2002; Dubessy
et al., 2008). The UII peptide is localized in epithelial
cells of kidney tubules and collecting ducts notably in
the distal convoluted tubules (Shenouda et al., 2002;
Langham et al., 2004; Maguire et al., 2004; Balat et al.,
2007). UII immunoreactivity is also present in renal
capillary endothelial cells (Shenouda et al., 2002). The
occurrence of substantial urinary UII concentrations in
healthy individuals whose plasma UII levels are un-
detectable (Matsushita et al., 2001) indicates that UII is
released by the human kidney. Consistent with this
notion, in sheep, plasma UII concentrations are higher
in the renal vein than in the renal artery (Charles et al.,
2005), thus identifying the kidney as a source of cir-
culating UII. In SHR, URP but not UII mRNA is elevated
in kidney compared with WKY rats (Hirose et al., 2009;
Forty and Ashton, 2013), suggesting a potential role for
URP in spontaneous hypertension.
The liver is also a documented site of UII and/or URP
production in human (Coulouarn et al., 1998; Totsune
et al., 2001; Sugo et al., 2003), monkey (Elshourbagy
et al., 2002), and sheep (Charles et al., 2005). In
cirrhotic patients, UII mRNA expression is increased
in liver (Liu et al., 2010a) and plasma UII concentra-
tion is elevated, particularly in the hepatic vein com-
pared with the hepatic portal vein (Heller et al., 2002).
In patients with chronic liver disease, elevated serum
UII is associated with disease severity and the extent
of portal hypertension (Kemp et al., 2007).
The UII gene is expressed in various endocrine
glands including the pituitary, pancreas, and adrenal
in human and rat (Coulouarn et al., 1998; Totsune
et al., 2001; Sugo et al., 2003), whereas the URP gene is
expressed in the testis, ovary, and placenta in human
(Sugo et al., 2003) and testis and seminal vesicle in
mouse (Dubessy et al., 2008). In contrast, UII is not
expressed in monkey endocrine glands (Elshourbagy
et al., 2002). UII and/or URP are also produced in other
organs, such as the thymus, lung, spleen, stomach, and
intestine (Coulouarn et al., 1998, 1999; Totsune et al.,
2001, 2003; Elshourbagy et al., 2002; Sugo et al., 2003;
Maguire et al., 2004; Dubessy et al., 2008), but marked
species differences occur even between phylogenetically
related animals.
In the European flounder, UII mRNA is expressed in
the rectum, intestine, and bladder (Lu et al., 2006). The
222 Vaudry et al.
UII gene is also expressed in flounder and grouper
endocrine glands, including pituitary, head kidney (where
the interrenal tissue is located), and ovary (Lu et al.,
2006; Sun et al., 2014).
Plasma UII/URP concentrations are in the same
range in human (2.5–24 fmol/ml; Totsune et al., 2004),
rat (2.9 fmol/ml; Prosser et al., 2006), sucker (40 fmol/ml;
Kobayashi et al., 1986), goldfish Carassius auratus
(16 fmol/ml; Kobayashi et al., 1986), and flounder (5–8
fmol/ml; Lu et al., 2006).
I. Urotensin II and Urotensin II–Related Peptide in
Tumor Cells
The initial characterization of human prepro-UII cDNA
was performed by analysis of a cDNA library obtained
from colon tumors (Coulouarn et al., 1998). Subsequent
studies revealed that various human cell lines, such as
T98G glioblastoma cells, IMR-32 neuroblastoma cells,
BeWo choriocarcinoma cells, SW-13 adrenocortical carci-
noma cells, DLD-1 colorectal adenocarcinoma cells, and
HeLa cervical cancer cells, express UII mRNA, whereas
NB69 neuroblastoma cells do not (Takahashi et al., 2001).
In addition, SW-13 adrenocortical carcinoma cells secrete
a mature form of UII (Takahashi et al., 2001) that may
act as a tumor growth–stimulating factor (Takahashi
et al., 2003). UII mRNA is also expressed in adrenal
tumors, including adrenocortical adenomas, adrenocortical
carcinomas, pheochromocytomas, ganglioneuroblastomas,
and neuroblastomas, but UII immunoreactivity is pres-
ent in only a small proportion of these tumor tissues
(Takahashi et al., 2003; Zeng et al., 2006). The occurrence
of elevated UII mRNA has been confirmed in human
adrenal tumors compared with non-neoplastic adrenal
tissue (Morimoto et al., 2008), suggesting the involvement
of UII in adrenal tumor growth and steroidogenesis. UII
mRNA and UII immunoreactivity are also present in the
human lung adenocarcinoma cell line A549 (Wu et al.,
2010). Synthetic UII stimulates A549 cell proliferation in
vitro and accelerates growth of A549 tumor xenografts in
nude mice (Wu et al., 2010). Immunoreactive UII and
URP are present in interstitial nodular lesions of lungs
from patients with lymphangioleiomyomatosis, a rare
disease characterized by abnormal proliferation of smooth
muscle–like cells in the pulmonary interstitium (Kristof
et al., 2010). UII promotes lung adenocarcinoma growth
via a mechanism involving activation of the nuclear factor
kB pathway and a proinflammatory microenvironment
(Zhou et al., 2012).
J. Phylogenetic Evolution of Urotensin II
1. Discovery of Two Novel Urotensin II–Related
Peptide-Like Genes in Teleosts. Until recently, the
UII family was thought to be composed of only two
members, namely UII and URP. As mentioned above
(see section II.A), UII was initially discovered in teleosts
(Pearson et al., 1980) and subsequently characterized
in amphibians (Conlon et al., 1992b) and mammals
(Coulouarn et al., 1998, 1999). Conversely, URP was first
identified in mammals (Sugo et al., 2003) and later in
birds (Tostivint et al., 2006) and amphibians (Konno
et al., 2013). Hence, it was logical to search for the
existence of URP in fish. Using degenerated primers
designed from the amino acid sequence of mammalian
URP, Nobata et al. (2011) successfully amplified a cDNA
encoding for a novel URP-like peptide in the Japanese
eel. A blast search revealed the occurrence of the same
peptide, now called URP1, in several other teleost
species including the Brook trout, the Atlantic salmon,
and the zebrafish. However, it also appeared that tele-
osts possess a second URP-like peptide named URP2
(Nobata et al., 2011; Parmentier et al., 2011). Recently,
the URP1 and URP2 genes were also identified in the
spotted gar, a nonteleost ray finned fish (Tostivint et al.,
2013). As shown in Fig. 1, URP1 and URP2 exhibit very
similar structures. Like tetrapod URP, fish URP1/2
possess a nonpolar residue (instead of an acidic residue
for UII) upstream the cyclic region. In contrast, at their
C-terminal extremity, fish URP1 and URP2 exhibit a
3-residue tail, whereas all tetrapod URPs carry a single
hydrophobic residue at their C terminus. It has thus
been hypothesized that the URP1 and URP2 genes were
two co-orthologs of the tetrapod URP gene, in very much
the same manner as the zebrafish and sucker UIIa(also
called UIIA) and UIIb(also called UIIB) genes (Nobata
et al., 2011), which are the two counterparts of the tet-
rapod UII gene. However, this view was recently in-
validated by synteny analysis (Parmentier et al., 2011).
Using this approach, it was found that the URP1 and
URP2 genes, although present only in fish, emerged
long before the tetrapod/fish split and thus represent
two distinct paralogous genes, in addition to the UII
and URP genes. As mentioned in section II.C, a true
ortholog of the URP gene does also exist in teleosts
and was recently characterized (Quan et al., 2012;
Tostivint et al., 2014). As in tetrapods, teleost URPs
possess a single residue extension at their C terminus.
In contrast, teleost URPs exhibit a 3-residue extension
at their N terminus, whereas most tetrapod URPs carry
only one residue at their N-terminal end (Fig. 1).
In zebrafish, URP mRNA is primarily localized in
motoneurons of the brainstem and spinal cord (sub-
mitted manuscript), as previously reported in tetra-
pods (Coulouarn et al., 1998, 1999; Dubessy et al.,
2008; Konno et al., 2013), indicating that the expres-
sion pattern of the URP gene has been strongly con-
served during vertebrate evolution. In contrast, the
expression patterns of the URP1 and URP2 genes
differ markedly from that of the URP gene. Although
most URP1- and URP2-expressing cells are found in
the spinal cord, these cells are located in close contact
with the ventral aspect of the central canal (Parmentier
et al., 2011; unpublished data). URP1 and URP2
mRNAs colocalize in the same cells that also express
the glutamate decarboxylase gene, identifying them as
Urotensin II and Its Receptor 223
CSF-contacting neurons (Vigh and Vigh-Teichmann, 1998).
It is likely that these URP1- and URP2-expressing neurons
correspond to the extra-urophysial UII system previously
described by Yulis and Lederis (1986, 1988).
2. Origin and Evolution of the Urotensin II Gene
Family in Vertebrates. The UII gene family thus ap-
pears to encompass four distinct paralogous genes,
namely the UII, URP, URP1, and URP2 genes. Synteny
analysis has revealed that the four chromosomal regions
comprising the UII/URP genes are highly conserved
across species. Indeed, all these regions contain paralogs
from at least 10 other gene families and thus clearly
represent a tetraparalogon (Fig. 4). These observations
support the view that the UII gene family has been
actually shaped through the two whole-duplication
rounds (2R) that occurred during early vertebrate
evolution (Van de Peer et al., 2010) (Fig. 5). They also
indicate that the original quartet of the UII/URP genes
has been fully preserved in teleosts (Parmentier et al.,
2011) and suggest that the existence of only two mem-
bers of the UII/URP gene family in tetrapods can be
ascribed to the loss of the URP1 and URP2 genes spe-
cifically in this lineage (Parmentier et al., 2011) (Fig. 5).
Synteny analysis also shows that the two copies of the
UII gene in teleosts, UIIa(or UIIA) and UIIb(or UIIB),
probably emerged through the teleost-specific whole-
genome duplication (also called 3R) (Fig. 5).
UII has been identified in all vertebrate classes,
including agnathans (Waugh et al., 1995). In contrast,
UII-like sequences have not been detected in the sea
lamprey (Petromyzon marinus; Decatur et al., 2013) and
in nonvertebrate chordates, such as tunicates or am-
phioxus. The existence of a UII-like peptide was recently
reported in the marine mollusc Aplysia californica
(Romanova et al., 2012), and UII has been found to
potentiate GABA
A
receptor–mediated chloride current
in Aplysia neurons (Sawada and Ichinose, 1999),
suggesting that UII is an ancient peptide that existed
before the emergence of vertebrates. However, two ob-
servations cast doubt on this hypothesis: 1) the sequence
of the Aplysia UII-like peptide is not located at the
C terminus of its precursor, as for all other members of
the UII/URP family; and 2) although several other
protostomian species do possess an orthologous UII-like
precursor gene, they are apparently devoid of UT-like
gene (personal communication).
3. Evolutionary Relationships between Peptides of the
Urotensin II and Somatostatin Families. UII was
initially described as a somatostatin-like peptide on
the basis of its structural similarities with somato-
statin (Pearson et al., 1980). UII and somatostatin
actually share several features including a disulfide
bridge and a common motif, Phe-Trp-Lys, which is
essential for their biologic activity (Fig. 6). Moreover,
the general organization of the UII and somatostatin
precursors is very similar (Tostivint et al., 2008). From
these observations, it was tempting to assume that UII
and somatostatin originate from a common ancestral
gene. However, it has long been considered that UII and
somatostatin were not phylogenetically related (Conlon
et al., 1997).
The evolutionary history of the somatostatin gene
family was recently clarified (Tostivint et al., 2004,
2006, 2008, 2013, 2014; Liu et al., 2010b). It has been
established that, in vertebrates, the current family
diversified from four ancestral genes that arose through
2R, namely SS1, SS2 (also called cortistatin in mammals),
SS5 and a fourth putative gene that was apparently lost
earlyduringevolution.Interestingly, synteny analy-
sis shows that the UII and SS2 genes, and the URP
and SS1 genes are closely linked on the same chromo-
some in all species investigated so far (Tostivint et al.,
2006), whereas, in teleosts, the URP1 and SS5 genes are
located on the same block of doubly conserved synteny
(Parmentier et al., 2011) (Fig. 4). These observations
indicate that the UII- and somatostatin-related genes
belong to the same tetraparalogon and thus evolved
in parallel. In addition, these data suggest that the UII
and somatostatin ancestral genes probably arose through
tandem duplication of a single ancestral gene (Tostivint
et al., 2006; Parmentier et al., 2011). It is likely that this
duplication occurred long before the emergence of verte-
brates. Worthy of note, a somatostatin-related peptide,
called allatostatin C, is present in arthropods (Mirabeau
and Joly, 2013).
Fig. 4. Schematic representation of the putative ancestral tetraparalogon
bearing genes of the UII and somatostatin families. The other families
displayed are as follows: ATPB1B, ATPase, Na
+
/K
+
transporting, bpolypeptide;
ATP13A, ATPase type 13A; CLIC, chloride intracellular channel; DVL,
dishevelled homolog 1 (Drosophila); FGF, fibroblast growth factor; MBNL,
muscleblind-like splicing regulator 2; RAP2, member of RAS oncogene family;
SENP, SUMO1/sentrin specific peptidase; TP, tumor protein. The gray
dashed boxes represent lost genes. The color code is the same as in Fig. 3.
(Adapted from Parmentier et al., 2011.)
224 Vaudry et al.
III. The Urotensin II Receptor
A. Cloning and Characterization of Urotensin II
Receptor
Although UII/URP and somatostatin/cortistatin share
substantial structural similarities, UII and URP are poor
agonists of somatostatin receptors (Malagon et al., 2008;
Nothacker et al., 1999), indicating that the biologic effects
of UII and URP are mediated through distinct recep-
tors. Thus, soon after the identification of human UII,
four independent laboratories using a reverse pharmacology
Fig. 5. A proposed evolutionary model for the evolution of the UII gene family. The names of the different paralogous genes are given in the boxes.
Crossed-out boxes represent lost genes. R, rounds of whole-genome duplication. ? denotes genes that have not been detected, either because of
incomplete genome assembly in the relevant species or because these genes have been lost during evolution. (Adapted from Tostivint et al., 2014.)
Fig. 6. Amino acid sequences of human urotensin II (hUII), human urotensin II–related peptide and somatostatin (SST). All three peptides exhibit
a disulfide bridge and a conserved Phe-Trp-Lys motif (red box).
Urotensin II and Its Receptor 225
strategy reported that the orphan receptor GPR14 pre-
viously characterized in rat (Marchese et a l., 1995) , a lso
called SENR (sensory epithelial neuropeptide-like
receptor) previously characterized in bovine (Tal et al.,
1995), was indeed the UII receptor (Ames et al., 1999;
Liu et al., 1999; Mori et al., 1999; Nothacker et al.,
1999). In contrast to most neuropeptides that usually
possess several receptor isoforms, GPR14/SENR, now
renamed UII receptor (UT) (Alexander et al., 2011), is
the only high affinity receptor for UII/URP known so far,
at least in mammals (see section III.G). This intronless
class A (rhodopsin family) G protein–coupled receptor
(GPCR) exhibits the highest degree of identity with the
somatostatin receptors SST
2
(26%) and SST
4
(27%) and
the m,d,andkopioid receptors (25–27%) (Marchese et al.,
1995; Fredriksson and Schiöth, 2005; http://www.iuphar-
db.org/DATABASE/FamilyMenuForward?familyId=65).
Human UT encompasses 389 amino acids and possesses
75% identity with rat GPR14 (Marchese et al., 1995; Ames
et al., 1999). As all class A GPCRs, UT is characterized by
a short N-terminal segment, an Asp residue in trans-
membrane domain 2 (TMD2) that is essential for ligand
binding, a D/ERY motif at the junction between TMD3
and the second intracellular loop 2 (ICL2), a NP(XX)Y
motif in TMD7 that is required for receptor internalization
and 12 potential Ser/Thr phosphorylation sites in the
intracellular loop 3 and the cytoplasmic tail (Fig. 7).
Conserved Cys
123
/Cys
199
residues, which likely form
a disulfide bridge, are present in the first and second
extracellular loops (ECL1 and ECL2), respectively.
Two putative N-glycosylation sites are also observed
in the N-terminal extracellular domain (Fig. 7). A putative
palmitoylation site (Cys
339
) is present in rat UT (Marchese
et al., 1995) but absent in human UT (Ames et al., 1999).
Because UT exhibits relatively high sequence identity
with opioid receptors (Fredriksson and Schiöth, 2005), a
d-opioid receptor model was used to build the first three-
dimensional (3D) molecular model of rat UT (Kinney
et al., 2002). Thus, goby UII was docked into this
homology model by imposing the alignment of the Lys
9
residue of UII toward the Asp
130
residue of TMD3 of rat
UT. Although all the conformational space available in
the binding pocket was not explored, the hypothetical
docking position suggests interactions between UT and
the key side chains of the Tyr
8
,Lys
9
,andTyr
10
residues
of UII (Kinney et al., 2002). Subsequently, a human
homology model, based on the X-ray structure of rhodopsin,
has been constructed. Because the Lys
9
residue of UII
was also aligned to the Asp
130
residue of UT, this latter
model yielded very similar information on the putative
ligand binding pocket (Lavecchia et al., 2005). Photo-
labeling experiments combined with site-directed mu-
tagenesis indicate that the Phe
6
residue of UII interacts
with the Met
184
and/or Met
185
residues of TMD4 of UT,
confirming the existence of a relatively deep binding
pocket (Boucard et al., 2003). Surface plasmon res-
onance assays show that UII and URP interact with
ECL2 and ECL3 but not ECL1, whereas the antago-
nist urantide only binds ECL2 (Boivin et al., 2006).
Docking studies confirm that UT agonists and antagonists
Fig. 7. Amino acid sequence and membrane topology of the human UII receptor. (Adapted from Kim et al., 2010, and Chatenet et al., 2013c.)
226 Vaudry et al.
differentially bind a UT model (Grieco et al., 2009).
Solution structure of the human UT
(281–300)
segment by
high-resolution NMR and molecular modeling in the
presence of UII also shows the occurrence of physical
interactions between UII and ECL3 (Boivin et al., 2008).
In dodecylphosphocholine micelles mimicking a mem-
brane environment, the human UT
(281–300)
sequence
exhibits a type III b-turn (Gln
285
–Leu
288
)followedby
an a-helical structure (Ala
289
–Leu
299
)thatincludesa
stretch of TMD7 (Boivin et al., 2008). The presence of a
binding site in rat UII ECL3 is confirmed by photo-
labeling data (Holleran et al., 2007). However, it is not
yet established whether this is a transient surface
interaction that precedes a deeper set of interactions
into the TMD bundle leading to receptor activation. This
contact may participate to the primary recognition pro-
cess of UT by UII and thus to the selectivity of the ligand,
or it may constitute an allosteric site of interaction. By
using the substituted-cysteine accessibility method (Javitch
et al., 2002), it was recently demonstrated that several
TMD3, TMD4, TMD5, TMD6, and TMD7 residues of rat
UT participate to the formation of the receptor binding
pocket (Holleran et al., 2009; Sainsily et al., 2013).
However, there are still numerous unsolved questions
regarding the molecular interactions between UT and
its natural ligands. Clearly, crystal structure character-
ization of UT and UT-UII complex is required to elucidate
the detailed mechanisms of binding and activation of the
receptor.
B. Signaling Mechanisms
Initial studies conducted in UT-transfected cells and
thoracic aorta segments indicate that UT is primarily
coupled to phospholipase C (PLC) activation through
the pertussis toxin-insensitive G protein Ga
q/11
(Fig. 8).
Upon UII binding to UT, activation of PLC causes
hydrolysis of phosphatidylinositol-4-5 bisphosphate
(PIP2) to inositol-1-4-5 triphosphate (IP
3
) and diacyl-
glycerol (Saetrum Opgaard et al., 2000) (Fig. 9A). The
involvement of PLC in UT signaling has been con-
firmed in cultured rat cortical astrocytes (Castel et al.,
2006; Jarry et al., 2010). IP
3
binds to the IP
3
receptor,
a calcium channel on the membrane of the endoplasmic
reticulum, resulting in an increase in cytoplasmic
calcium levels (Parys and de Smedt, 2012) (Fig. 9B).
UII-induced intracellular calcium mobilization has now
been documented in a number of cell types, including
the porcine renal epithelial cell line LLCPK1 (Matsushita
et al., 2003), human aorta endothelial cells (Brailoiu
et al., 2008), and rat aorta vascular smooth muscle cells
(Rodríguez-Moyano et al., 2013). In endothelium-denuded
rat aorta, protein kinase C mediates the synergistic action
of UII and angiotensin II (Wang et al., 2007). In addition,
in rat spinal cord cholinergic neurons, UII causes calcium
influx from the extracellular space via N-type Ca
2+
channels, and this effect is mediated through the protein
kinase A pathway (Filipeanu et al., 2002), whereas in
arterial smooth muscle cells, UII stimulates Ca
2+
influx
via L-type Ca
2+
channels (Sauzeau et al., 2001) indicating
that, depending on the cell type, UII-induced Ca
2+
entry
occurs through various types of voltage-operated Ca
2+
channels. Of note, UII provokes membrane depolariza-
tion in cholinergic neurons from the ventral tegmentum
(Clark et al., 2005) that is likely involved in the UII-evoked
control of rapid eye movements (de Lecea and Bourgin,
2008).
UT is also coupled to Ga
i/o
, leading to activation of
the mitogen-activated protein kinase (MAPK) pathway
(Fig. 8). Thus, UII stimulates P38MAPK and extracel-
lular signal-regulated kinase 1/2 in UT-transfected cell
lines (Ziltener et al., 2002), cardiac myocytes (Zou et al.,
2001; Onan et al., 2004b), vascular smooth muscle cells
(Watanabe et al., 2001b; Tamura et al., 2003), airway
smooth muscle cells (Chen et al., 2004), endothelial cells
(Matsushita et al., 2003; Guidolin et al., 2010), and
endothelium-denuded rat aorta (Tasaki et al., 2004).
UII also stimulates proliferation of endothelial pro-
genitor cells through activation of p38 and p44/42
MAPK (Xu et al., 2012). The stimulatory effect of UII
on P38MAPK and extracellular signal-regulated kinase
1/2 in neonatal rat cardiomyocytes and cardiac fibro-
blasts depends on transactivation of epidermal growth
factor receptor (Onan et al., 2004b; Chen et al., 2008;
Liu et al., 2009). UT stimulates phosphorylation of
C-Jun N-terminal protein kinase in cardiac side pop-
ulation cells and inhibits proliferation of these stem/
progenitor cells (Gong et al., 2011). UII-induced activa-
tion of the small GTPase RhoA and its downstream
effector Rho-kinase mediates the contractile activity of
the peptide on rat vascular rings (Sauzeau et al., 2001),
its mitogenic effect on rat vascular smooth muscle cells
(Sauzeau et al., 2001), its chemoattractant activity on
human monocytes (Segain et al., 2007), and its stimulatory
effect on collagen synthesis and migration of adventitial
fibroblasts (Zhang et al., 2008). UII increases phosphory-
lation of both Akt and its downstream target glycogen
synthase kinase-3 in rat cardiomyocytes (Gruson et al.,
2010a). In these cells, UII also phosphorylates b-catenin
(Gruson et al., 2010a). Because the Akt/glycogen synthase
kinase-3 signaling pathway plays a pivotal role in
cardiomyocyte hypertrophy (Sugden et al., 2008),
these observations suggest that UT antagonists may
prove useful for the treatment of cardiac hypertrophy.
A possible implication of phospholipase A
2
in the
contractile effect of UII has long been postulated
(Gibson, 1987) (Fig. 8). As a matter of fact, UII increases
the release of arachidonic acid from UT-transfected
Chinese hamster ovary (CHO) cells (Mori et al., 1999),
and the effect of UII on CHO and human embryonic
kidney cells are attenuated by a phospholipase A
2
in-
hibitor (Lehner et al., 2007). In addition, UII-induced
contractions of guinea pig ileum or frog systemic arch,
bladder, and ileum are blocked by the cyclooxygenase
inhibitor indomethacin (Yano et al., 1994, 1995; Horie
Urotensin II and Its Receptor 227
et al., 2005). Similarly, UII- and URP-induced vasodi-
lation in the rat heart is significantly attenuated by
indomethacin (Prosser et al., 2006), suggesting that the
biologic actions of UII are mediated, at least in part,
through stimulation of prostaglandin synthesis. How-
ever, prostaglandins are apparently not involved in the
vasoconstrictive effects of UII in dogfish (Hazon et al.,
1993), rat (Gibson, 1987; Itoh et al., 1987), and rabbit
aorta (Saetrum Opgaard et al., 2000). In the isolated rat
heart, nitric oxide (NO) and prostacyclin modulate the
constrictor response to UII (Gray et al., 2001).
UII stimulates the expression of the NADPH oxidase
subunits P22phox and NOX4 and potently activates the
production of reactive oxygen species (ROS) in human
pulmonary artery smooth muscle cells (Djordjevic et al.,
2005) (Fig. 8), suggesting that the peptide may play
a role in pulmonary hypertension through activation of
NADPH oxidases. Generation of ROS also plays an
important role in UII signaling in cardiac fibroblasts
(Chen et al., 2008). In fact, UII-mediated ROS generation
inhibits Src homology 2–containing tyrosine phosphatase
activity, thereby facilitating epidermal growth factor
receptor transactivation (Liu et al., 2009).
Most studies related to UT-associated intracellular
signaling pathways have been conducted with UII.
Although UII and URP produce similar biologic
actions, there is now evidence that the two peptides
may interact distinctively with UT and exert differen-
tial effects (Chatenet et al., 2013a,b,c). For instance,
in rat astrocytes, pertussis toxin, which inhibits
Gi/o-mediated processes, significantly decreases UII-evoked
incorporation of [
3
H]inositol into phosphatidyl-inositol
phosphates but does not affect URP-induced [
3
H]inositol
incorporation (Jarry et al., 2010). Morever, URP ac-
celerates the dissociation rate of membrane-bound
[
125
I]UII, whereas UII has no noticeable effect on
[
125
I]URP dissociation kinetics (Chatenet et al., 2013b).
It thus appears that, although both UII and URP can
activate UT, they may exert differential modulatory
effects.
Fig. 8. Signaling pathways associated with UT after UII or URP activation. AC,adenylylcyclase;Akt,proteinkinase B; cAMP, cyclic adenosine
monophosphate; EGFR, epidermal growth factor receptor; ERK1/2, extracellular signal-reduced kinase 1/2; GSK-3b, glycogen synthase
kinase-3b; JNK, c-Jun N-terminal kinase; P38, P38 mitogen-activated protein kinases; PIP
2
, phosphatidylinositol 4,5-bisphosphate; PKA,
protein kinase A; PKC, protein kinase C; PLA
2
, phospholipase A
2
; RhoA, Ras homolog gene family, member A; ROCK, Rho kinase; ROS, reactive
oxygen species.
228 Vaudry et al.
C. Structure-Activity Relationships
The in vitro activity of UII and URP analogs has
been measured by two complementary approaches,
i.e., displacement of [
125
I]UII binding and measure-
ment of [Ca
2+
]
i
in UT-transfected cells. Functional
characterization of the spasmogenic effect of the designed
compounds has been determined using various ex vivo
paradigms (Leprince et al., 2008). The most common
test consists in measuring the contractile response of
de-endothelialized aortic rings from the proximal
portion of the rat aortic arch (Itoh et al., 1987;
Douglas et al., 2000a; Rossowski et al., 2002; Brkovic
et al., 2003; Labarrère et al., 2003; Clozel et al., 2004;
Ishihata et al., 2006). Deletion of N- or C-terminal
amino acids of UII indicates that the C-terminal cyclic
octapeptide UII
(4–11)
(Fig. 10, compound 3)represents
the minimal sequence of UII with full biologic activity
(Itoh et al., 1987; Perkins et al., 1990; Kinney et al.,
2002; Brkovic et al., 2003; Labarrère et al., 2003).
Consistent with this observation, the primary struc-
ture of this C-terminal sequence has been highly
conserved across the vertebrate phylum, whereas the
N-terminal linear fragment is quite variable, both in
length and amino acid composition (Fig. 1). It should
also be recalled that the sequence of the C-terminal
octapeptide of UII is almost identical to that of URP.
Alanine and D-amino acid scanning studies of UII and
URP converge to demonstrate that the -Phe-Trp-Lys-
Tyr- motif within the cyclic sequence is the core of the
bioactivity with different contributions on UT binding
and activation (Flohr et al., 2002; Kinney et al., 2002;
Brkovic et al., 2003; Labarrère et al., 2003; Chatenet
et al., 2004). In particular, the Tyr residue is clearly
involved in UT binding and the Lys residue in UT
activation, whereas the Phe residue plays a dual role
(Chatenet et al., 2006). The importance of the disulfide
bridge in UII has been known for a long time (McMaster
et al., 1986). Reduced goby UII or linear UII analogs in
which the cystine moiety is replaced with two isosteric
serine residues, two S-substituted cysteines, or two
alanines are weak agonists or devoid of contractile activity
(McMaster et al., 1986; Flohr et al., 2002; Brkovic et al.,
2003; Labarrère et al., 2003; Guerrini et al., 2005).
Similarly, replacement of the disulfide bond by a lactam
bridge of various sizes yields less active or inactive analogs
(Grieco et al., 2002b). Concurrently, the cysteine-free
head-to-tail cyclic hexapeptide -Ala-Phe-Trp-Lys-Tyr-Ala-
displays a lower affinity compared with UII (Foister et al.,
2006). Replacement of the Tyr residue of this cyclic
hexapeptide with a b-naphtalene moiety enhances bind-
ing affinity but impairs selectivity for UT versus somato-
statin receptors (Foister et al., 2006). N-terminal acylation
is well tolerated and does not impair the binding
affinity and the functional activity of UII and URP
(Coy et al., 2002; Brkovic et al., 2003; Labarrère et al.,
2003; Chatenet et al., 2004; Song et al., 2006b). How-
ever, capping of the N-terminal function may improve
the stability of the analogs against proteolysis (Perkins
et al., 1990; Kinney et al., 2002; Labarrère et al., 2003).
Similarly, amidation of the C-terminal Val residue does
not significantly affect the ability of UII to contract rat
thoracic aortic rings (Coy et al., 2002; Brkovic et al.,
2003; Labarrère et al., 2003).
Several structure-activity relationship studies have
focused on the optimization of the Trp-Lys-Tyr triad
for the development of UT ligands with potent ago-
nistic or antagonistic activities. In URP as in UII, the
Fig. 9. Effect of human UII on inositol phosphate turnover and intracellular
calcium concentration ([Ca
2+
]
i
) in human UT-transfected CHO cells. (A) In
cells labeled with [
3
H]inositol, graded concentrations of UII, in the presence of
Li block, induces a dose-dependent increase of inositol phosphate (IPx)
formation. DPM, disintegrations per minute. (B) Time course effect of UII
(100 nM, black bar) on [Ca
2+
]
i
in Fura 2-loaded cells. In the presence of
extracellular Ca
2+
, a biphasic response in observed, i.e., a peak originating
from intracellular calcium stores (as a consequence of IP formation) and
a plateau phase caused by an entry of extracellular Ca
2+
. In the absence of
extracellular Ca
2+
, the response is monophasic with the plateau-phase missing.
(C) Effect of graded concentrations of UII on the peak [Ca
2+
]
i
response.
[Reprinted from McDonald et al. (2007). Used with permission.]
Urotensin II and Its Receptor 229
tryptophan residue appears to be relatively tolerant to
stereoisomer substitution (Flohr et al., 2002; Brkovic
et al., 2003; Labarrère et al., 2003; Chatenet et al., 2004;
Guerrini et al., 2005). For instance, [DTrp
4
]URP retains
substantial binding affinity on human UT-transfected
cells and a weak ability to contract de-endothelialized
aortic rings. However, [DTrp
4
]URP totally suppresses the
UII-evoked contractile response (Chatenet et al., 2004),
indicating that this compound behaves as a partial
agonist of UT. Replacement of the Trp residue with
tetrahydroisoquinoline-1-carboxylic acid (Tiq) or L-1,2,3,4-
tetrahydronorharman-3-carboxylic acid (Tpi) in URP yields
two potent UT receptor agonists, [Tiq
4
]URP and [Tpi
4
]URP
(Chatenet et al., 2013a), suggesting that the indole ring
Fig. 10. Chemical structures of various pepditic ligands of UT. The residue(s) modified from the original scaffold are indicated in red.
230 Vaudry et al.
of the Trp residue is not critical for receptor interaction
(binding) and could in fact be involved in the intramolecular
stabilization of the bioactive conformation of URP
(Chatenet et al., 2013a). On the basis of the structural
similarities existing between UII and somatostatin on
the one hand (Pearson et al., 1980) and between UT
and SST4 on the other hand (Marchese et al., 1995), it
has been hypothesized that the interactions of UII
with UT may be similar to those previously reported
for somatostatin with SST
4
(Kinney et al., 2002). In
particular, it has been proposed that the lateral amine
function of the Lys residue of UII may establish a
physical interaction with the carboxyl group of the Asp
130
moiety of TMD3 of UT (Kinney et al., 2002; Lavecchia
et al., 2005) that is likely involved in receptor activation
(see section III.A). Thus, analogs with a reduced distance
between the side-chain NH
2
group and the peptide
backbone in positions 8 and 5 of UII and URP,
respectively, which should limit receptor activation,
may exhibit antagonistic properties. Indeed, UII-related
compounds containing ornithine, 2,4-diaminobutyric
acid (Dab), or 2,3-diaminopropionic acid instead of the
lysine residue display significant attenuation of the
effects of UII. In particular, [Orn
8
]UII (Fig. 10, com-
pound 4) induces a rightward shift of the concentration-
response curve of UII on rat aortic strip contraction
(Camarda et al., 2002a) and prevents UII-evoked plasma
extravasation in mice (Vergura et al., 2004). However,
[Orn
8
]UII stimulates calcium mobilization in human and
rat UT-transfected cells (Camarda et al., 2002a), in-
dicating that this compound also acts as a partial UT
agonist. Conversely, the [Orn
5
]URP analog (Fig. 10, com-
pound 5), which retains high binding affinity (Chatenet
et al., 2004), behaves as a pure selective antagonist in both
rat aortic ring contraction and astrocyte [Ca
2+
]
i
mobilization
assays (Diallo et al., 2008; http://www.iuphar-db.org/
DATABASE/FamilyMenuForward?familyId=65).
To date, only a few peptidic UT superagonists have
been designed (Leprince et al., 2008). Consistent with
the observation that radio-iodinated UII ([
125
I]UII)
possesses high affinity for native UT (Maguire et al.,
2000) and UT-transfected cells (Nothacker et al., 1999),
it was found that [3-iodo-Tyr
6
]UII
(4–11)
(Fig. 10, com-
pound 6) is five times more potent than UII and UII
(4–11)
in causing rat aortic ring contraction (Labarrère et al.,
2003). Similarly, substitution of the tyrosine residue
with hindered aromatic amino acids such as (2-naphtyl)-
L-alanine and biphenylalanine increases the binding
affinity and/or the biologic activity of the analogs,
probably through an enhancement of the hydrophobic
interactions within the binding pocket (Kinney et al.,
2002). In contrast, double iodination of the Tyr
9
side-
chain, to produce [3,5-diiodo-Tyr
9
]UII
(4–11)
,doesnot
modify the potency of the peptide to mobilize [Ca
2+
]
i
in
HEK293 cells expressing rat UT but causes a marked
decrease of the efficacy, indicating that the diiodinated
analog behaves as a partial agonist (Batuwangala
et al., 2009b). One of the most effective cycle modifica-
tions on activity is the single replacement of the Cys
5
residue of UII
(4–11)
with a penicillamine, which yields
[Pen
5
]UII
(4–11)
, also named P5U (Fig. 10, compound 7),
an analog that exhibits an affinity 3 times as high as
that of UII and an increased potency in the isolated rat
thoracic aorta assay (Grieco et al., 2002a; Patacchini
et al., 2003). Finally, replacement of the Tyr
9
residue
in the P5U sequence with the benzothiazolyl-alanine
or the (3,4-Cl)Phe moities leads to analogs with pEC
50
values at least 1.4 log higher than that of P5U being the
most potent UT agonists discovered to date (Carotenuto
et al., 2014).
Several peptidic antagonists have been designed
by combining multiple point modifications. For in-
stance, urantide ([Pen
5
,DTrp
7
, Orn
8
]UII
(4–11)
; Fig. 10,
compound 8) acts as a UT antagonist in the rat aorta bio-
assay (Patacchini et al., 2003; Camarda et al., 2004) but
stimulates Ca
2+
mobilization in CHO cells transfected
with human UT (Camarda et al., 2004; Grieco et al., 2005).
Another analog, UFP-803 ([Pen
5
,DTrp
7
,Dab
8
]UII
(4–11)
;
Fig. 10, compound 9), which does not evoke any con-
traction of thoracic aorta rings, shifts to the right the
UII concentration-response curve (Camarda et al., 2006).
However, UFP-803 is about 10-fold less potent than
urantide to antagonize UII-induced contraction (Patacchini
et al., 2003; Camarda et al., 2004, 2006). The cyclic
somatostatin analog SB-710411, i.e., Cpa-c[DLys-Pal-
DTrp-Lys-Val-Cys]Cpa-NH
2
(Cpa: 4-chlorophenylalanine;
Pal: 3-pyridylalanine; Coy et al., 2000; Fig. 10, com-
pound 10) inhibits UII-induced contraction of isolated
rat aorta (Behm et al., 2002) but exerts agonistic activity
in monkey arteries (Behm et al., 2004b). Rather than
a species-dependent process, these divergent responses
may be ascribed to an assay-dependent phenomenon
inasmuch as [Orn
8
]UII behaves as an antagonist in the
rat aorta assay and as an agonist at the recombinant rat
UII (Camarda et al., 2002a). These discordant behaviors
can be accounted for by different UT expression levels
and/or different signal transduction–coupling efficiency.
It should be noted, however, that another somatostatin
analog, GSK-248451 (Cin-c[DLys-Pal-DTrp-Orn-Val-Cys]-
His-NH
2
;Cin:4-chlorocinnamoyl;Fig.10,compound11),
acts as a potent UT antagonist in both native mamma-
lian tissues and recombinant cell systems (Behm et al.,
2006).
Functional studies have shown that UII and URP
exert both common and specific biologic activities (see
section III.B). Until recently, none of the UT agonists
and antagonists (either peptidic or nonpeptidic) could
selectively mimic/block the effects of UII or URP. How-
ever, two recent reports describe the design of allosteric
modulators of UT, i.e., urocontrin ([Bip
4
]URP; Bip: 4,49-
biphenylalanine; Fig. 10, compound 12) and urocontrin
A(UCA;[Pep
4
]URP; Pep: 4-(phenylethynyl)-phenylalanine;
Fig. 10, compound 13)andratUII
(1–7)
(Fig. 10, compound
14), that can discriminate the biologic activities exerted by
Urotensin II and Its Receptor 231
UII and URP both ex vivo and in vivo (Chatenet et al.,
2013a,b,c). In particular, in the rat and monkey aortic
ring contraction assays, UCA decreases the maximum
response to human UII but has no noticeable effect on
URP-induced vasoconstriction (Chatenet et al., 2013b).
Reciprocally, the N-terminal region of rat UII, i.e., rat
UII
(1–7)
, significantly reduces the contractile activity of
URP but does not affect that of rat UII (Chatenet et al.,
2013b). The antagonistic activity of UCA can be ascribed
to an allosteric mechanism, because this compound in-
hibits UII and URP binding by means of a noncompet-
itive process.
D. Design of Nonpeptidic Urotensin II Receptor
Agonists and Antagonists
Over the past 15 years, the design of agonists and
antagonists of UII and URP has been carried out to
facilitate the delineation of their physiologic roles and to
explore new therapeutic strategies. Structure-activity
relationship studies (Flohr et al., 2002; Kinney et al.,
2002; Brkovic et al., 2003; Labarrère et al., 2003;
Chatenet et al., 2004; Guerrini et al., 2005; Leprince
et al., 2008; Merlino et al., 2013) led to the discovery of
peptide-derived analogs acting as potent agonists or
antagonists (Behm et al., 2002; Grieco et al., 2002a;
Herold et al., 2003; Patacchini et al., 2003; Carotenuto
et al., 2004b; Grieco et al., 2005; Carotenuto et al.,
2006; Chatenet et al., 2012, 2013a,b). However, those
molecules are usually not considered as the best
drug candidates, because their pharmacodynamic and
pharmacokinetic properties (bioavailability, metabolic
stability, biodistribution) are not optimal. Therefore, the
identification and evaluation of nonpeptidic urotensinergic
compounds were achieved following approaches based
on analysis of the molecular arrangements of UII-
and URP-related ligands or the 3D structure of the
UT receptor, together with high-throughput screening
(HTS).
Structure-activity relationship studies and NMR
conformational evaluations (Bhaskaran et al., 1994;
Flohr et al., 2002; Grieco et al., 2002b; Chatenet et al.,
2004; Lescot et al., 2007) of UII, URP, and analogs, in
conditions replicating UT-bound or -unbound ligand,
have revealed that the endocyclic triad -Trp-Lys-Tyr- is
the key pharmacophore (see sections II.D and III.C).
The spatial parameters determined from these studies
have been used to carry out virtual 3D screenings. For
instance, a virtual screening performed by Flohr et al.
(2002) on an Aventis chemolibrary, followed by a
biologic testis using fluorometric imaging plate reader
(FLIPR)–based functional assay, led to the identifica-
tion of S6716 (Fig. 11, compound 15), a benzamidine-
derived antagonist with an IC
50
of 400 nM. Similarly,
a few years later, Lescot et al. (2007) established a
pharmacophore template after NMR studies of UII
and molecular dynamics calculations of nonpeptidic
UII antagonists identified by Takeda Chemical Industries
(Osaka, Japan) and Actelion (Allschwil, Switzerland).
Subsequently, a virtual screening of their compound
database (6626 molecules) revealed six chemical sub-
stances that showed affinities in the low micromolar
range, the best being compound 16 (Fig. 11; IC
50
:1.4mM).
The 3D arrangement of UT was also used (Kinney
et al., 2002; Lavecchia et al., 2005; Lescot et al., 2008b)
to determine the particular physicochemical require-
ments of the binding pocket of the receptor and help
for the design of new nonpeptidic UT ligands. Although
appealing, this approach remains complex because
GPCRs are dynamic biomolecules exhibiting confor-
mational changes upon activation (Preininger et al.,
2013). Nevertheless, the 3D information might be
very useful for understanding the binding process of
existing leads, as shown by docking studies performed
with the nonpeptidic UII agonist AC-7954 (Lavecchia
et al., 2005) (Fig. 11, compound 17;AcadiaPharma-
ceuticals, San Diego, CA; EC
50
:316nMforthe
racemic mixture) (Croston et al., 2002). Noteworthy,
AC-7954 is the precursor of the potent UT agonists
(+)-FL68 (EC
50
: 50 nM), a 6,7-dimethylated derivative
of the lead compound (Lehmann et al., 2005), as well
as (+)-FL104 (Fig. 11, compound 18,AcadiaPharma-
ceuticals; EC
50
: 32 nM) and its optimized (+)-(S)-
naphtyl–containing derivative (Fig. 11, compound 19,
Acadia Pharmaceuticals; EC
50
: 23 nM) (Lehmann et al.,
2006, 2009).
HTS is, by far, the most common strategy for dis-
covering template candidates for a drug. This approach
has been applied for identifying nonpeptidic UT ligands
and many hits were obtained for both antagonists and
agonists. Among the first series of antagonists to be
reported, the aminoalkoxybenzylpyrrolidines, identified
by GlaxoSmithKline (Brentford, UK), showed prom-
ising antagonistic properties (Dhanak et al., 2001; Jin
et al., 2005). This series is illustrated by compound
SB-436811 (Fig. 11, compound 20), an optimized hit
that exhibits a good affinity for human UT (K
i
: 200 nM)
but a weak binding potency on rat UT (K
i
:3.2mM).
GlaxoSmithKline also described the preparation of
sulfonamide derivatives (Dhanak et al., 2002; Douglas
et al., 2005). In particular, the lead sulfonamide mole-
cule, SB-611812 (Fig. 11, compound 21), which binds to
rat UT (K
i
: 121 nM), antagonizes UII-elicited rat aortic
contractions and exhibits very good pharmacokinetic
properties (;100% oral bioavailability and a 5-hour
half-life), has been used in a rat congestive heart failure
model. After 8 weeks of treatment, health improvement
was observed, as demonstrated for instance by the de-
crease of right ventricular systolic pressure, cardiomyo-
cyte hypertrophy, and lung edema, which altogether
reduced the overall mortality (Bousette et al., 2006a).
Further refinements within the sulfonamide series
gave rise to the UT antagonist SB-706375 (Fig. 11,
compound 22), which potently blocks UII binding (low
nanomolar range) with a reversible mode of action,
232 Vaudry et al.
and inhibits contraction of the rat isolated aorta, as well
as intracellular calcium mobilization (Douglas et al.,
2005). Likewise, the Johnson & Johnson group, after
applying an HTS protocol to a library of about 500,000
molecules, found new antagonist ligands based on the
piperazinophtalimide chemotype (Lawson et al., 2009).
Their lead compounds showed only a moderate antag-
onistic activity and were metabolically unstable. To
improve the drug properties of their hits, they in-
troduced various chemical groups in the scaffold and
discovered JNJ-39319202 (Fig. 11, compound 23; rat and
human IC
50
in FLIPR: 4.8 and 150 nM, respectively, and
human UT K
i
: 35 nM) (Lawson et al., 2009; Maryanoff and
Kinney, 2010). Interestingly, this piperazinophtalimide
derivative contains a sulfonamide function, which appears
to enhance the interaction of the ligand with the UT
receptor. In parallel, Lawson et al. (2009) explored a series
of piperazinoisoindolinone-based derivatives that are mole-
cules structurally close to the piperazinophtalimide-derived
compounds. Their study showed that the removal of one
carbonyl group in the phtalimide moiety does not much
change the activity, because compound 24 exhibits single-
digit nanomolar affinity and antagonistic potency (Lawson
et al., 2009).
Quinolone and quinoline templates have been used
by a few pharmaceutical companies [such as compound
25 from GlaxoSmithKline, compound 26 from Encysive
Pharmaceuticals (Houston, TX), and compound 27
from Takeda] for the design of UT antagonists (Dhanak
and Knight, 2002; Kessler and Wu, 2009; Tarui et al.,
2001). These compounds show variable potencies. Simi-
larly, Actelion carried out a structural study of
4-ureidoquinoline derivatives and, in 2004, the company
reported the characterization of ACT-058362 (Fig. 11,
compound 28), also known as palosuran (Clozel et al.,
2004). This molecule exhibits high inhibitory binding
potency on human UT receptor (IC
50
:3.6nM).Ina
functional FLIPR assay with human UT, an IC
50
of 17 nM
Fig. 11. Chemical structures of various nonpeptidic agonists and antagonists of the UT receptor. Compounds 17,18, and 19 are agonists; the
remaining compounds are antagonists.
Urotensin II and Its Receptor 233
was reported. By contrast, palosuran is poorly recog-
nized by the rat UT. Hence, Actelion initiated human
clinical trials with patients afflicted by hypertension
and diabetic nephropathy. Yet, no significant changes
in renal hemodynamic parameters, such as glomerular
filtration rate and renal blood flow, were observed and
the clinical trials were stopped in 2005 (Maryanoff and
Kinney, 2010).
Finally, various optimized chemical substances,
based on a benzazepine template (Fig. 11, compound 29
from Takeda), as well as on carboxamide cores, such
as 5,6-bisaryl-2-pyrimidinecarboxamide, 5,6-bisaryl-2-
pyridinecarboxamide, and 5,6-bisaryl-2-pyrazinecarboxamide
(for example, compound 30 from Sanofi-Aventis, Paris,
France), were reported (Tarui et al., 2002; Altenburger
et al., 2008, 2009, 2011). The corresponding com-
pounds exhibited potent antagonistic properties,
and thus Sanofi launched a phase I clinical trial
with a 5,6-bisaryl-2-pyridinecarboxamide derivative
(SAR101099). However, this trial was discontinued
because of the lack of efficacy in diabetic nephropathy
(en.sanofi.com/Images/29618_20120208-2011_Results_
EN.pdf).
This section represents a summary of nonpeptidic
ligands for the urotensinergic system; more information
can be obtained in the reviews from Cosenzi (2008),
Lescot et al. (2008a), Maryanoff and Kinney (2010), and
Merlino et al. (2013). Thus, the literature shows that
most major pharmaceutical companies are involved in
a research program aimed at designing highly potent
agonists and antagonists of the UT receptor. So far,
excellent ligands have been developed and some com-
pounds have even been evaluated in clinical trials.
However, mixed clinical results (Maryanoff and Kinney,
2010; Portnoy et al., 2013; en.sanofi.com/Images/
29618_20120208-2011_Results_EN.pdf) were obtained,
for instance by Actelion, Sanofi, and GlaxoSmithKline,
and consequently, several trials were stopped. It was
recently found that UII and URP exhibit not only
common but also dissimilar biologic activities (Prosser
et al., 2008; Jarry et al., 2010; Doan et al., 2012). Thus,
ligands able to discriminate between the UII and URP
effects have been developed (Chatenet et al., 2012,
2013a,b,c). Pharmacological studies using these com-
pounds confirmed that the urotensinergic system is far
more complex than initially thought. These observa-
tions might explain some of the failures of clinical trials
and, therefore, this aspect should be considered when
designing new UT ligands.
E. Distribution of Urotensin II Receptor in the Central
Nervous System
The localization of UT mRNA has been determined
in the brain and spinal cord by RT-PCR and in situ
hybridization histochemistry (Liu et al., 1999; Clark
et al., 2001; Gartlon et al., 2001; Totsune et al., 2001;
Elshourbagy et al., 2002; Jégou et al., 2006; Dubessy
et al., 2008), and the localization of UII binding sites
has been studied by autoradiography using [
125
I]UII
or [
125
I]URP as a radioligand (Maguire et al., 2000;
Clark et al., 2001; Jégou et al., 2006; Bucharles et al.,
2014). The distribution and relative density of UT mRNA
and UII binding sites in the rat CNS are compared
in Table 1.
High concentrations of UT mRNA are found in most
regions of the CNS, including the cerebral cortex,
olfactory bulb, hippocampus, amygdala, pineal gland,
hypothalamus, tegmentum, brainstem, cerebellum,
and spinal cord (Gartlon et al., 2001; Jégou et al.,
2006). Expression of UII mRNA occurs in neurons
(Jégou et al., 2006), astrocytes (Castel et al., 2006;
Desrues et al., 2012), and endothelial cells (Spinazzi
et al., 2006).
In rat, the expression of UT mRNA is particularly
intense in the piriform cortex, the pineal gland, the
arcuate nucleus of the hypothalamus, the choroid plexus,
the locus coeruleus, the dorsal motor nucleus of the vagus
nerve, the trigeminal nucleus, the facial nucleus, the
medial superior olive, the medioventral periolivary
nucleus, the nucleus of the trapezoid body, the pontine
nuclei, and in the Purkinje cell and granule cell layers of
the cerebellum (Jégou et al., 2006; Hunt et al., 2010).
High levels of UT mRNA are also observed in the
entorhinal cortex, the piriform cortex, the tenia tecta, in
several regions of the amygdala including the nucleus of
the lateral olfactory tract, the bed nucleus of the accessory
olfactory tract, the anterior and posterolateral cortical
amygdaloid nuclei, the medial amygdaloid nucleus and
the posteromedial amygdalohippocampal transition area,
in the parabigeminal nucleus, the medial habenular
nucleus, the supraoptic and ventromedial hypothalamic
nuclei, the area postrema, the dorsal laterodorsal and
ventral tegmental nuclei, the interpeduncular nucleus,
the nucleus of the solitary tract, the nucleus ambiguus,
the nucleus abducens, the hypoglossal nucleus, the
principal sensory nucleus, the lateral periolivary nucleus,
the supragenuate nucleus, the inferior olivary complex,
the magnocellular subdivision of the red nucleus, and
layers 9 and 10 of the ventral horn of the spinal cord
(Jégou et al., 2006; Hunt et al., 2010). In the mesopontine
tegmentum area and the spinal cord, the UT gene is
strongly expressed in motoneurons (Clark et al., 2001,
2005; Jégou et al., 2006; Bruzzone et al., 2010). The
fact that UII induces an increase in [Ca
2+
]
i
in cultured
rat motoneurons indicates that the UT mRNA is
translated into functional UT receptor (Filipeanu et al.,
2002).
Autoradiographic labeling with [
125
I]UII confirmed
the presence of UII binding sites in several areas of the
rat brain that actively express the UT gene such as
the endopiriform nucleus in the olfactory system, the
subiculum complex in the hippocampal formation, the
medial amygdaloid nucleus, the parabigeminal nu-
cleus in the visual system, the medial aspect of the
234 Vaudry et al.
TABLE 1
Distribution of UT mRNA and UII binding sites on the rat brain
The distribution of
125
I-labeled UII binding sites has been described in three reports: 1) Maguire et al., 2000; 2) Clark
et al., 2001; 3) Jégou et al., 2006. [Reprinted from Jégou et. al. (2006). Used with permission.]
Structure GPR14 mRNA UII Binding Sites
Isocortex +/++
Allocortex
Cingulate cortex +/++
Insular cortex +
Orbital cortex +
Retrosplenial cortex +
Entorhrinal cortex ++/+++
Olfactory system
Main olfactory bulb
Mitral cell layer ++
Internal granular layer ++
Glomerular layer +
Anterior olfactory nucleus ++
Dorsal endopiriform nucleus ++ Yes (2, 3)
Piriform cortex +++/++++
Tenia tecta +++
Olfactory tubercle +++
Claustum ++
Basal ganglia
Caudate putamen +/2
Globus pallidus —
Accumbens nucleus +/2Yes (2)
Ventral pallidum +/2
Islands of Calleja —
Substantia nigra
Pars compacta ++
Pars reticularis —
Subthalamic nucleus +/++
Ventral tegmental area + Yes (2)
Septum
Lateral septal nucleus, dosal + Yes (2, 3)
Lateral septal nucleus, intermediate +
Lateral septal nucleus, ventral +
Horizontal limb of the diagonal band of Broca +
Hippocampal formation
Ammon’s horn
Stratum oriens Patchy labeling
Pyramidal cell layer +++/++++
Stratum radiatum Patchy labeling
Dentate gyrus +++/++++
Subiculum complex ++ Yes (2)
Amygdala
Nucleus of the lateral olfactory tract +++
Bed nucleus of the accessory olfactory tract +++
Anterior cortical amygdaloid nucleus +++
Posterolateral cortical amygdaloid nucleus +++
Posteromedìal cortical amygdaloid nucleus ++
Amygdalopiriform transition area ++
Medial amygdaloid nucleus +++ Yes (3)
Posteromedial amygdalohippocampal transition area +++
Basolatetal amygdaloid complex ++
Basomedial amygdaloid complex ++
Central amygdaloid complex ++
Bed nucleus of the stria terminalis, lateral + Yes (2, 3)
Visual system
Parabigeminal nucleus +++ Yes (3)
Lateral geniculate nuclei, ventral and dorsal +/2Yes (2, 3)
Pretectum + Yes (3)
Superior colliculus +
Epithalamus
Pineal gland ++++
Habenular nucleus
Medial +++ Yes (2)
Lateral ++
Thalamus
Paraventricular thalamic nucleus ++
Anterodorsal thalamic nucleus ++
Anteroventral thalamic nucleus +/++ Yes (2, 3)
Centromedian thalamic nucleus +
Reticular thalamic nucleus +
Mediodorsal thalamic nucleus +
Reuniens thalamic nucleus +
(continued )
Urotensin II and Its Receptor 235
TABLE 1—Continued
Structure GPR14 mRNA UII Binding Sites
Rhomboid nucleus +
Ventrolatetal thalamic nucleus +
Ventroposterior lateral thalamic nucleus +
Ventroposterior medial thalamic nucleus +
Ventromedial thalamic nucleus +
Posterior thalamic nuclear group +
Paratenial thalamic nucleus +
Zona incerta ++
Hypothalamus
Anterior hypothalamic area, anterior +
Anterior hypothalamic area, posterior ++
Anterior medial preoptic nucleus —
Anteroventral preoptic nucleus —
Medial preoptic area —
Medial preoptic nucleus +/++ Yes (2)
Lateral preoptic area —
Median preoptic nucleus ++
Lateroanterior hypothalamic nucleus +
Magnocellular preoptic nucleus —
Supachiasmatic nucleus ++
Supraoptic nucleus +++
Ventromedial hypothalamic nucleus +++
Lateral hypothalamic area +
Posterior hypothalamic area +
Dorsomedian hypothalamus, dorsal +
Paraventricular nucleus, magnocellular part ++
Paraventricular nucleus, median parvocellular +
Arcuate nucleus +++/++++
Mammillary nucleus, medial, lateral ++
Circumventricular organs
Area postrema +++
Choroid plexus ++++
Reticular formation
Paramedian reticular nucleus Patchy Labeling
Medullary nucleus, ventral, dorsal
Ventral Patchy Labeling
Dorsal —
Lateral paragigantocellular nucleus Patchy Labeling
Rostroventrolateral reticular nucleus ++
Dorsal paragigantocellular nucleus —
Gigantocellular reticular nucleus Patchy Labeling
Ventral Patchy Labeling
Alpha Patchy Labeling
Intermediate reticular nucleus +
Parvocellular reticular nucleus Patchy Labeling
Pontine reticular nuclei Patchy Labeling
Periaqueducal gray +
Cuneiform nucleus +
Dorsal tegmental nucleus +++
Ventral tegmental nucleus +++
Laterodorsal tegmental nucleus +++ Yes (2)
Microcellular tegmental nucleus —
Pedunculopontine tegmental nucleus +/2Yes (2, 3)
Deep mesencephalic nucleus —
Raphe complex
Dorsal raphe nucleus ++
Median raphe nucleus ++
Raphe pallidus nucleus ++
Interpeduncular nucleus ++/+++ Yes (2)
Locus coeruleus ++++
Brainstem nuclei associated to autonomic functions
Nucleus of the solitary tract +++
Dorsal motor nucleus of the vagus +++/++++
Ambiguus nucleus +++
Parabrachial nucleus
Medial ++
Lateral ++
Motor nuclei
Oculomotor nucleus ++
Trochlear nucleus ++
Trigeminal nucleus ++++
Abducens nucleus +++ Yes (1)
Facial nucleus +++/++++
Hypoglossal nucleus +++
Somatosensory system
(continued )
236 Vaudry et al.
habenular nucleus, the medial preoptic nucleus, the
laterodorsal tegmental nucleus in the reticular forma-
tion, the interpeduncular nucleus, the abducens nu-
cleus, the pontine nuclei, and the Purkinje cell layer
(Maguire et al., 2000; Clark et al., 2001; Jégou et al.,
2006). However, a number of brain nuclei that are
enriched with UT mRNA do not contain detectable
amounts of UII binding sites. This mismatch suggests
that, in certain brain regions, the UT protein may be
occupied by endogenous UII or URP. Consistent with
this notion, it has been shown that, in various tissues,
UII binds tightly to its receptor in a quasi-irreversible
manner (Qi et al., 2005; Song et al., 2006b; Du et al.,
2010), and dissociation of UII from cat UT appears to be
very slow (Aiyar et al., 2005) (Fig. 12). Alternatively, in
brain regions that contain high concentrations of
UT mRNA but are devoid of UII binding sites, the re-
ceptors may be transported along the axons to dis-
tant projecting areas (Jégou et al., 2006). This latter
hypothesis would also explain why UII binding sites
are observed in a few brain regions that are virtually
devoid of UT mRNA, e.g., the nucleus accumbens and
the pedunculopontine tegmental nucleus (Jégou et al.,
2006). A recent study has shown that the distribution of
[
125
I]URP binding sites totally overlaps that of [
125
I]UII
(Bucharles et al., 2014). Intriguingly, UII and URP
binding sites are observed along the wall of the fourth
ventricle (Bucharles et al., 2014), suggesting that the
urotensinergic system may regulate chemical commu-
nication between CSF and brain parenchyma.
In the mouse CNS, RT-PCR analysis revealed that
the expression pattern of UT is globally similar to that
TABLE 1—Continued
Structure GPR14 mRNA UII Binding Sites
Mesencephalic trigeminal nucleus ++++
Principal sensory nucleus, dorsomedial ++/+++
Nucleus of the spinal tract
Oral +/++
Caudal +
Interpolar part +
External cuneate nucleus ++
Cuneate nucleus —
Paratrigeminal nucleus ++
Auditory system
Lateral superior olive ++
Medial superior olive ++++
Medioventral periolivary nucleus ++++
Lateroventral periolivary nucleus +++
Nucleus of the trapezoid body ++++
Dorsal cochlear nucleus ++
Ventral cochlear nucleus
Anterior ++
Posterior ++
Ventral nucleus of the lateral lemniscus +/++
Inferior colliculus +
Medial geniculate body +
Vestibular system
Superior vestibular nucleus +
Lateral vestibular nucleus +
Medial vestibular nucleus ++
Prepositus hypoglossal nucleus ++
Supragenuate nucleus +++
Precerebellar nuclei
Pontine nuclei ++++ Yes (2, 3)
Reticulotegmental nucleus of the pons ++
Inferior olivary complex +++
Lateral reticular nucleus ++
Red nucleus
Parvocellular ++
Magnocellular +++
Cerebellum
Purkinje cell layer ++++ Yes (3)
Granular layer ++++
Molecular layer —
Medial cerebellar nucleus +/++
Interposed cerebellar nucleus +/++
Lateral cerebellar nucleus +/++
Spinal cord
Layer 2–4++
Layer 5 +
Layer 7–8++
Layer 9 +++
Layer 10 ++/+++
The symbols provide a semiquantitative evaluation of the density of UT mRNA: ++++, very high density; +++, high
density; ++, moderate density; +, low density; —, no hybridization signal.
Urotensin II and Its Receptor 237
described in rat with high concentrations of UT mRNA
in the septum, hippocampus, amygdala, hypothalamus,
cerebellum, medulla oblongata, and spinal cord (Dubessy
et al., 2008). In the anterior horn of the spinal cord,
intense expression of UT is observed in motor neurons
(Liu et al., 1999; Sun et al., 2014).
In the human CNS, UT mRNA is present in the
cerebral cortex, hypothalamus, and medulla oblongata
(Totsune et al., 2001), whereas, in the cynomolgus
monkey, UT mRNA is found in the spinal cord but not
in the cerebral cortex and cerebellum (Elshourbagy
et al., 2002). In addition, UII peptide is also detected in
the CSF of pregnant women (Cowley et al., 2005). The
occurrence of UII binding sites has also been reported
in the human brain (Maguire et al., 2000).
In the European flounder, the UT gene is strongly
expressed in the spinal cord and in the caudal neu-
rosecretory system (Lu et al., 2006). In the flounder
and the orange-spotted grouper Epinephelus coioides,
UT transcripts are also present in all regions of the
brain including the forebrain, midbrain, hypothala-
mus, and hindbrain (Lu et al., 2006; Sun et al., 2014).
F. Distribution of Urotensin II Receptor in
Peripheral Organs
The localization of UT mRNA and UT protein has
been investigated by RNase protection assay, Northern
blot analysis, RT-PCR, immunohistochemistry, and
binding experiments. Early reports on the character-
ization of rat and bovine GPR14/SERN, now renamed
UT (see section III.A), revealed that, in mammals, this
receptor is actively expressed in the retina and heart
muscle (Marchese et al., 1995; Tal et al., 1995).
Subsequent studies showed that UT mRNA is widely
expressed in peripheral organs such as the eye, heart,
pancreas, lung, and skeletal muscle (Ames et al., 1999;
Liu et al., 1999; Davenport and Maguire, 2000; Dubessy
et al., 2008; Wang et al., 2009). In particular, in mouse,
the highest expression of UT mRNA is observed in the
lung (Dubessy et al., 2008), suggesting a role of UII/URP
in respiratory function. Consistent with this hypothesis,
UII induces in vitro a concentration-dependent contrac-
tion of airways and pulmonary blood vessels from the
cynomolgus monkey (Hay et al., 2000).
In the cardiovascular system, the UT gene is expressed
in the atrium, ventricle, coronary artery, thoracic aorta,
left internal thoracic artery, great saphenous vein, and
umbilical vein (Ames et al., 1999; Davenport and
Maguire, 2000; Matsushita et al., 2001; Zhang et al.,
2007). Autoradiographic analysis indicates that [
125
I]UII
binds to rat aorta and human left ventricle and coronary
artery (Maguire et al., 2000). At the cellular level, UT-like
immunoreactivity is observed in arterial and venous
smooth muscle cells and cardiomyocytes (Maguire et al.,
2008).
The UT transcript is found in the kidney of human
(Ames et al., 1999; Lehner et al., 2007), rat (Gartlon
et al., 2001; Hirose et al., 2009; Mori et al., 2009;
Forty and Ashton, 2013), and mouse (Lehner et al.,
2007). In the rat kidney, the UT gene is expressed in
glomerular arterioles, thin ascending limbs, and inner
medullary collecting ducts (Song et al., 2006a; Forty
and Ashton, 2013). Quantitative receptor autoradiog-
raphy confirms the presence of [
125
I]UII binding in
the human kidney cortex (Maguire et al., 2000) and
in the rat kidney medulla (Disa et al., 2006). At the
cellular level, UT-like immunoreactivity is located in
renal tubular cells, vascular smooth muscle cells, and
vascular endothelial cells of the rat kidney (Mori
et al., 2009).
In the human endocrine system, UT mRNA is
expressed in the adrenal gland (Takahashi et al.,
2003) and pancreas (Ames et al., 1999). Immunohisto-
chemical staining indicates that the UT protein occurs
in the human adrenal medulla (Morimoto et al., 2008).
UT mRNA is also expressed in the rat testis.
In the European flounder and the killfish Fundulus
heteroclitus, UT mRNA is expressed in heart, ovary,
bladder, kidney, pituitary, and gill (Lu et al., 2006; Evans
et al., 2011). In the flounder and the grouper, UT-like
immunoreactivity is evident in vascular elements irri-
gating osmoregulatory tissues such as kidney glomeruli
and collecting ducts and the primary and secondary
lamellae of the gill (Lu et al., 2006; Sun et al., 2014).
G. Urotensin II Receptor in Tumor Cells
The UII gene is expressed in a number of human
cell lines including T98G glioblastoma cells, IMR-32
neuroblastoma cells, NB69 neuroblastoma cells, BeWo
Fig. 12. [
125
I]human UII binding to recombinant human UT. (A) [
125
I]UII
binding is presented with Scatchard analysis of the binding isotherm.
Addition of a peptidase inhibitor cocktail (+PI; i.e., amastatin, bestatin,
phosphoramidon, and captopril) does not affect binding. (B) Addition of
an excess of unlabeled UII (dotted line) failstoinduceradioliganddissociation.
[Reprinted from Song et al. (2006b). Used with permission.]
238 Vaudry et al.
choriocarcinoma cells, SW-13 adrenocortical carcinoma
cells, DLD-1 colorectal adenocarcinoma cells, and HeLa
cervical cancer cells (Takahashi et al., 2001). The UT
gene is also expressed in pheochromocytomas, adreno-
cortical adenomas (including adenomas with primary
aldosteronism, adenomas with Cushing syndrome, and
nonfunctioning adenomas), adrenocortical carcinomas,
ganglioneuroblastoma, and neuroblastomas (Takahashi
et al., 2003; Zeng et al., 2006). Of note, all these cell
lines except NB69 neuroblastoma cells also express
UII mRNA (Takahashi et al., 2001, 2003). Functional
human UT has been characterized in rhabdomyosar-
coma SJRH30 and TE671 cell lines (Douglas et al.,
2004b; Batuwangala et al., 2009a). Both UT mRNA and
UT protein are present in human lung adenocarcinoma
A549 cells and exogenous UII activates proliferation
of these cells in vitro and in vivo (Wu et al., 2010).
UII-evoked lung adenocarcinoma growth is likely
mediated through the nuclear factor kB pathway (Zhou
et al., 2012). Abundant expression of UT mRNA and
UT protein is observed in the interstitial nodular lesions
of patients with lymphangioleiomyomatosis, whereas
UT mRNA is not expressed in normal human lungs
(Kristof et al., 2010). UT mRNA expression is signifi-
cantly elevated in androgen-dependent LNCaP prostate
cancer cells and reduced in androgen-independent PC3
and DU145 prostate cancer cells (Grieco et al., 2011).
Interestingly, there is a significant correlation between
UT expression and the prognosis of human prostate
adenocarcinoma, suggesting the potential use of UT as
a prognostic marker for prostate cancer (Grieco et al.,
2011). Collectively, these findings indicate that further
studies should be pursued on the role of UT in the
pathogenesis of various cancers as well as its potential
as a diagnostic and prognostic marker.
H. Phylogenetic Evolution of Urotensin II Receptor
As mentioned above (see section III.A), UT exhibits the
highest degree of sequence identity with somatostatin,
opioid, and galanin receptors. Consistent with this ob-
servation, phylogenetic analysis shows that all of these
receptors group into the same clade, called the g-group
of rhodopsin receptors (Mirabeau and Joly, 2013).
The close evolutionary relationships between UII- and
somatostatin-related peptides (Parmentier et al., 2011;
see section II.J.3) on the one hand and between UT and
somatostatin receptors on the other hand are consistent
with the hypothesis that all these peptides, together with
their cognate receptors, coevolved from a single ancestral
ligand-receptor pair (Tostivint et al., 2006, 2014).
Although the UII family encompasses several mem-
bers (i.e., two in tetrapods and up to five in teleosts),
until recently only one UII/URP receptor had been
identified. However, in a recent study, Larhammar
et al. (2012) provide evidence that UT also belongs
to a multigenic family and show that the vertebrate
ancestor likely possessed five distinct UT subtypes.
They propose that the single ancestral UT gene was
quadrupled in 2R and that one of these copies un-
derwent a local duplication (Fig. 13). It now appears
that all five UT subtypes have been preserved in some
reptile species, notably in the anole lizard (Anolis
carolinensis), whereas in teleosts and birds, for instance,
only four are still present. In contrast, placental mam-
mals have lost four of the five ancestral UT genes (Fig. 13).
These new data reveal a totally unexpected complexity of
the urotensinergic system in vertebrates (Tostivint et al.,
2014). Further studies are now needed to grasp the full
biologic significance of such a complexity, particularly in
teleosts where many ligands and receptors coexist. In any
event, it is now clear that the relative simplicity of the
urotensinergic system in placental mammals (i.e., two
ligands for only one receptor) should no longer be viewed
as a general rule.
IV. Biologic and Pharmacologic Effects of
Urotensin II and Urotensin II–Related Peptide
A. Effects of Urotensin II/Urotensin II–Related
Peptide in the Central Nervous System
The widespread distribution of UT in the brain and
spinal cord indicates that UII and URP may regulate
various neurophysiological and behavioral activities. As
a matter of fact, central administration of UII induces
a number of biologic effects (Watson and May, 2004; do
Rego et al., 2005; Nothacker and Clark, 2005; Vaudry
et al., 2010).
1. Action on Rapid Eye Movement Sleep. The pres-
ence of UT mRNA and UII binding sites in cholinergic
neurons of the pedunculopontine tegmental nucleus (PPT)
and the lateral dorsal tegmental area (Clark et al., 2001),
two structures of the pons-midbrain transition area
involved in the control of rapid eye movement (REM)
sleep (Baghdoyan et al., 1984; Webster and Jones, 1988;
Quattrochi et al., 1989; Steriade and McCarley, 1990),
lends credence to the idea that the UII system may be
implicated in the regulation of the sleep-wake cycle.
Consistent with this hypothesis, intracerebroventricular
administration of UII or local bilateral injection of UII
into the PPT increases the number of REM sleep
episodes in rat (Huitron-Resendiz et al., 2005; de Lecea
and Bourgin, 2008). Interestingly, only a low dose
(0.6 pmol) of UII significantly augments the amount of
REM sleep, whereas a 10-fold higher dose is ineffective.
The UT antagonist SB-710411 blocks the UII-induced
REM sleep response. Whole cell recording from rat brain
slices revealed that UII triggers cholinergic PPT neurons
by activating a slow inward current (Huitron-Resendiz
et al., 2005).
High concentrations of UT mRNA and UII binding
sites are also observed in the locus coeruleus (Jégou
et al., 2006), a structure involved in the regulation of the
sleep-wake cycle (Jacobs, 1985). In rat brain slices, UII
Urotensin II and Its Receptor 239
stimulates the release of norepinephrine in a concentra-
tion-dependent manner, and this effect is blocked by the
UT antagonist UFP-803 (Ono et al., 2008). The UII-
evoked norepinephrine release is also inhibited by the
central-type benzodiazepine agonist midazolam (Kawaguchi
et al., 2009), suggesting that the effect of UII on REM
sleep may be mediated, at least in part, through in-
teraction with the GABA
A
receptor. In addition, UII
triggers the release of three other wakefulness-promoting
neurotransmitters, i.e., dopamine, serotonin, and hista-
mine (Ono et al., 2008).
2. Action on Food Intake and Energy Homeostasis.
TheUTgeneisactivelyexpressedinbrainregions
that are known to control feeding behavior, both in
the hypothalamus, i.e., the arcuate nucleus and the
ventromedial hypothalamic nucleus, and in the brain-
stem, i.e., the nucleus of the solitary tract and the
parabrachial nucleus (Jégou et al., 2006). However,
pharmacological studies aimed at investigating the
effect of intracerebroventricular injections of UII on
feeding behavior have led to divergent results. Thus, in
food-restricted mice, intracerebroventricular adminis-
tration of graded doses of UII (10 ng–10 mgpermouse)
provokes a bell-shaped increase in food consumption
with a maximum effect at a 100 ng per mouse dose,
associated with a dose-related increase in water intake
with a maximum effect at a 10 mg per mouse dose (do
Rego et al., 2005). In contrast, in normally fed rats,
intracerebroventricular injection of UII induces a
modest decrease of food intake (Yasuda et al., 2012).
Fig. 13. A proposed evolutionary model for the UT gene family. The names of the different paralogous genes are given in the boxes. Crossed-out boxes
represent lost genes. R, rounds of the whole-genome duplication. [Adapted from Tostivint et al. (2014).]
240 Vaudry et al.
Concurrently, intracerebroventricular administration of
UII stimulates the expression of the genes encoding the
uncoupling proteins UCP1 and UCP3 in brown adipose
tissue and causes an increase in sympathetic nerve
activity (Yasuda et al., 2012). In unanesthetized sheep,
intracerebroventricular infusion of UII causes a marked
increase of plasma glucose (Watson and May, 2004; Hood
et al., 2005). Collectively, these observations indicate that
UII may act centrally to regulate food intake and energy
expenditure, but the neuronal systems mediating these
effects are still unknown.
InthemarinesnailAplysia californica, the UII-related
peptide (see section II.J.2) modifies the electrophysiolog-
ical activity of neurons that play a role in satiety and/or
aversive signaling (Romanova et al., 2012), supporting
the view that the involvement of UII in the control of
feeding behavior has been conserved during evolution
from molluscs to rodents.
3. Action on Cardiovascular Activity. Ahighdensity
of UT mRNA is present in magnocellular neurons of the
paraventricular and supraoptic nuclei and in discrete
regions of the medulla oblongata and pons that are
involved in the control of the multisynaptic cardiovas-
cular reflex arc, including the nucleus of the solitary
tract, the dorsal nucleus of the vagus, the ambiguus
nucleus, the gigantocellular and paragigantocellular
reticular nuclei, the locus coeruleus, and the para-
brachial nuclei (Jégou et al., 2006). This observation
suggests that UII/URP may act centrally to regulate
cardiovascular activity. In normotensive rats, intra-
cerebroventricular administration of 1–10 nmol UII
provokes an increase in arterial blood pressure and
heart rate within 5 minutes after the onset of injection
(Lin et al., 2003a) and the pressure action is exaggerated
in hypertensive rat (Lin et al., 2003b). Similarly, in
sheep, intracerebroventricular administration of UII
(0.2 nmol/kg) provokes a prolonged increase in heart
rate, cardiac output, and blood pressure (Watson et al.,
2003; Hood et al., 2005). In rat, the nicotinic receptor
antagonist pentolinium abrogates the pressor and
tachycardic responses to intracerebroventricularly ad-
ministered UII (Lin et al., 2003a), whereas in sheep, the
b-adrenoreceptor blocker propranolol suppresses the
cardiac responses to intracerebroventricularly injected
UII (Hood et al., 2005). These findings indicate that the
central cardiac actions of UII are mediated through
cholinergic and/or adrenergic neuronal pathways. Intra-
cerebroventricular injection of UII also causes a robust
increase in cortical blood flow (Huitron-Resendiz et al.,
2005; Chuquet et al., 2008). After induction of cerebral
ischemia by occlusion of the right cerebral artery in rat,
intracerebroventricular injection of UII induces a signifi-
cant increase of hemispheric infarction volume, suggesting
that UII exacerbates brain damage caused by an ischemic
insult (Chuquet et al., 2008). Local administration of UII
in discrete brain nuclei produces differential cardiovascu-
lar responses. For instance, microinjection of UII into the
paraventricular or arcuate nucleus of the rat hypothala-
mus significantly increases arterial blood pressure and
heart rate (Lu et al., 2002). In contrast, microinjection
of UII into the A1 (noradrenergic cells) area of the
medulla oblongata induces a dose-related depressor and
bradycardic response (Lu et al., 2002). In normotensive
rats, pentolinium suppresses hypertension and tachy-
cardia induced by intracerebroventricularly injected UII
(Lin et al., 2003a), indicating that the central cardio-
vascular action of UII is mediated through activation of
the sympathetic system. The fact that the hypertensive
effect of UII is significantly greater in SHR than in
WKY (Lin et al., 2003b) provides further evidence for
a role of UII in the pathogenesis of hypertension. In
unanesthetized trout and eel, intracerebroventricular
injection of UII evokes an increase in arterial blood pres-
sure and heart rate (Lancien et al., 2004; Nobata et al.,
2011; Le Mével et al., 1996, 2008, 2012). In these two
teleost fish species, the central vasopressor action of UII
is mimicked by URPs, but the duration of the effect of
URPs is shorter (Nobata et al., 2011; Le Mével et al., 2013).
4. Action on Locomotor Activity. The high expres-
sion of UII and URP mRNAs in motoneurons of the
brainstem and spinal cord (Dun et al., 2001; Chartrel
et al., 1996, 2004; Coulouarn et al., 1998, 1999, 2001;
Pelletier et al., 2002, 2005; Dubessy et al., 2008) and
the presence of UT mRNA and UT protein in various
regions of the CNS implicated in the regulation of motor
activity and arousal, such as the cortex, thalamus,
amygdala, striatum, nucleus accumbens, motor nuclei
of the brainstem, and spinal cord (Ames et al., 1999;
Liu et al., 1999; Clark et al., 2001; Gartlon et al., 2001;
Jégou et al., 2006; Bruzzone et al., 2010) strongly
suggest that UII/URP may affect locomotor activity.
Indeed, intracerebroventricular injection of UII in
mouse (10 nmol) and rat (5–15 nmol) induces a dose-
dependent increase of ambulatory movements (Gartlon
et al., 2001; Clark et al., 2005; do Rego et al., 2005, 2008)
(Fig. 14). In rat, UII excites mesopontine cholinergic
neurons (Clark et al., 2005). In mouse cervical spinal
synaptosomes, UII induces a concentration-dependent
stimulation of acetylcholine release (Bruzzone et al.,
2010). In frog, UII accelerates spontaneous transmitter
release at motor nerve terminals (Brailoiu et al., 2003).
These observations indicate that, in mammals and
amphibians, UII may control motor functions through
modulation of motoneuron activity both centrally within
the spinal cord and peripherally at the neuromuscular
junction. In unanesthetized trout, intracerebroventricu-
lar injection of UII or URPs (5–50 pmol) causes a long-
lasting increase in motor activity (Lancien et al., 2004;
Le Mevel et al., 2013). Of note, the minimum effective
doses of UII/URPs influencing locomotion in trout are
10 times lower than those necessary to affect respiratory
or cardiovascular parameters (Lancien et al., 2004).
5. Action on Anxiety and Depression. TheUTgeneis
expressed in brain regions involved in the control of
Urotensin II and Its Receptor 241
motivation, vigilance, and arousal such as the bed
nucleus of the stria terminalis, the locus coeruleus,
the ventral tegmental area, the laterodorsal tegmental
nucleus, and the nucleus ambiguus (Clark et al., 2001;
Gartlon et al., 2001; Jégou et al., 2006; Hunt et al.,
2010). Intracerebroventricular injection of 15 pmol–3
nmol UII in mice causes anxiogenic-like effects as
assessed in the black-and-white, hole-board, and ele-
vated plus maze tests (Matsumoto et al., 2004; do Rego
et al., 2005, 2008) (Fig. 15). The anxiogenic action of UII
is attenuated by central-type benzodiazepine receptor
antagonists (Kawaguchi et al., 2009). UT mRNA and
UII binding sites also occur in brain regions involved in
the pathophysiology of mood disorders such as the
limbic system (i.e., cerebral cortex, nucleus accumbens,
amygdala, hippocampus), thalamic nuclei, and striatum
(Gartlon et al., 2001; Matsushita et al., 2001; Totsune
et al., 2001; Jégou et al., 2006). Intracerebroventricular
injection of UII in mice causes an increase of the
immobilization time in the tail suspension test and the
forced swimming test (do Rego et al., 2005), two classic
tests used to assess depressive-like behavior. Because
otherwise UII induces hyperlocomotion in mice (do Rego
et al., 2005), the prolonged immobility time observed
in the forced swimming and tail suspension tests cannot
be accounted for by nonspecific effects on locomotor
activity.
6. Action on Ventilation. In trout, intracerebroven-
tricular injection of 0.5 nmol UII or URP1 induces
a strong increase in the ventilation amplitude and
ventilation frequency (Le Mével et al., 2008, 2013).
7. Neuroendocrine Actions. The expression of UT
mRNA in hypothalamic nuclei, notably in the arcuate
nucleus, the supraoptic nucleus, the ventromedial
hypothalamic nucleus, the magnocellular aspect of
the paraventricular nucleus, and the median preoptic
nucleus (Jégou et al., 2006) provides the anatomic
substrate for neuroendocrine actions of UII. In support
of this hypothesis, intracerebroventricular adminis-
tration of UII (0.2 nmol/kg) in unanesthetized ewes
provokes a marked increase in plasma adrenocortico-
tropin (ACTH) and adrenaline levels (Watson et al.,
Fig. 14. Effect of UII on locomotor activity. Mice were given intracerebroventricular injections of vehicle or graded doses of UII (10–10,000 ng/mouse)
and the horizontal (A) and vertical (B) components of motor activity were measured for four consecutive periods of 10 minutes. Mean 6S.E.M. of data
from 14 mice per group. Dunnett’sttest (*P,0.005; **P,0.01; ***P,0.001). [Reprinted from do Rego et al. (2005). Used with permission.]
242 Vaudry et al.
2003). In contrast, intravenous injection of UII (2–40
nmol/kg) does not significantly affect ACTH secretion
(Watson et al., 2003), indicating that UII acts centrally
to stimulate ACTH secretion. Similarly, in rat, intra-
cerebroventricular injection of UII causes an increase
of plasma cortisol level (Watson et al., 2008). The
anxiogenic-like activity of UII (do Rego et al., 2008) is
consistent with a central effect of UII on the hypo-
thalamo-pituitary-adrenal axis. The expression of UT
mRNA in parvocellular neurons of the paraventricular
nucleus (Jégou et al., 2006) suggests that UII-induced
ACTH secretion may be ascribed to a direct stimulatory
action on corticotropin-releasing hormone-producing neu-
rons. Consistent with this notion, intracerebroventricular
injected UII causes an increase of Fos immunoreactivity
in the paraventricular nucleus that contains a dense
population of corticotropin-releasing hormone neurons
(Watson et al., 2008).
In fish, UII exerts neuroendocrine actions at differ-
ent levels of the hypothalamo-pituitary complex. Thus,
at the hypothalamic level, UII stimulates mRNA ex-
pression of growth hormone–releasing hormone and
inhibits mRNA expression of the two isoforms of so-
matostatin, SS1 and SS2, in the orange-spotted grouper
Fig. 15. Effect of UII on anxiety-like behavior. Mice were given intracerebroventricular injections of vehicle or graded doses of UII (1–10,000
ng/mouse) and were placed at the center of an elevated plus-maze 10 minutes later. The number of entries (A), the time spent (B), and the distance
traveled (C) in the open arms, in the central area, and in the closed arms of the maze were measured for 5 minutes. Mean 6S.E.M. of data from 10 to
20 mice per group. Dunnett’sttest (*P,0.05; **P,0.01; ***P,0.001). [Reprinted from do Rego et al. (2005). Used with permission.]
Urotensin II and Its Receptor 243
(Sun et al., 2014). At the pituitary level, UII inhibits
prolactin secretion in tilapia (Grau et al., 1982; Rivas
et al., 1986) and stimulates growth hormone mRNA
expression in grouper (Sun et al., 2014).
B. Effect of Urotensin II/Urotensin II–Related Peptide
on the Cardiovascular System
The most studied aspect of UII is its vascular activity
(Camarda et al., 2002b; Kompa et al., 2004; Barrette
and Schwertani, 2012; Zemanciková and Török, 2013).
Although previously thought to be endothelin-1, UII
has been demonstrated to be the most potent physio-
logic vasoconstrictor peptide (Ames et al., 1999). Both
endothelium-dependent vasorelaxation and endothelium-
independent vasoconstriction mediated by UII have been
demonstrated in rat-isolated aorta (Gibson, 1987). Despite
being characterized as the most potent isolated vasocon-
strictor, the constrictive effects of UII are variable and
appear to be dependent on the vascular bed (Itoh et al.,
1987, 1988) and the species from which it is isolated
(Douglas et al., 2000b). In addition to its potent vasoactive
effects, UII has several other crucial roles in cardiovascular
physiology and pathophysiology, many of which have only
begun to be identified in recent years. Under normal
physiologic conditions, UII/UT binding is integral in the
control of vascular tone, blood pressure, and maintaining
blood glucose levels (Douglas and Ohlstein, 2000; Douglas
et al., 2000b; Loirand et al., 2008). The physiologic roles of
UII also include mediating the release of endothelial-
derived vasodilators, such as NO, and thus controlling
the contraction and relaxation of vascular smooth
muscle cells (Itoh et al., 1987; Gardiner et al., 2001;
Stirrat et al., 2001). The pathologic roles for the UT
receptor system are still emerging. There is evidence
implicating this system in conditions such as conges-
tive heart failure, atherosclerosis and coronary artery
disease, and both systemic and pulmonary hyperten-
sion, cirrhosis, and chronic renal failure, among others.
There is also evidence suggesting that positive and
negative inotropy, arrhythmias, cardiomyocyte hyper-
trophy, vascular smooth muscle cell proliferation, extra-
cellular matrix production, and hyperpermeability of
endothelial cells are among some of the other cardio-
vascular effects of the urotensinergic system in patho-
physiological conditions (Russell, 2004). This section
will provide an overview of what is currently known
about the physiologic and pathophysiological roles of
UII and URP in the cardiovascular system, with par-
ticular emphasis on the implications in cardiovascular
disease.
1. Remodeling of Vascular Tissue. UII promotes the
formation of the extracellular matrix and proliferation
of various cardiovascular cell types (Matsushita et al.,
2001, 2003; Sauzeau et al., 2001; Watanabe et al.,
2001b; Papadopoulos et al., 2008; Albertin et al., 2009;
Guidolin et al., 2010; Dai et al., 2011; Xu et al., 2012).
For instance, UII stimulates proliferation of vascular
smooth muscle cells via epidermal growth factor re-
ceptor transactivation (Tsai et al., 2009). The effect of
UII on smooth muscle cells growth is abrogated by the
Rho-kinase inhibitor Y-27632 and by the membrane-
permeant RhoA inhibitor TAT-C3 (Sauzeau et al., 2001),
indicating that the growth-stimulating effect of UII is
mediated through activation of the small GTPase RhoA
and its downstream effector Rho-kinase.
UII also promotes proliferation of bone marrow-
derived endothelial progenitor cells (Xu et al., 2012).
In both rat and human endothelial cells, UII exerts a
proangiogenic action in vitro that is comparable to that
of the reference angiogenic cytokine fibroblast growth
factor-2 (Spinazzi et al., 2006; Albertin et al., 2009). In
human umbilical vein endothelial cells, UII increases
mRNA and protein expression of the proangiogenic
factors vascular endothelial growth factor, endothelin-1,
and adrenomedullin (Albertin et al., 2011).
In neonatal rat cardiac fibroblasts, UII increases the
expression of mRNAs for procollagens type I and III
and fibronectin (Tzanidis et al., 2003). UII also stim-
ulates proliferation of neonatal cardiac fibroblasts and
this effect is suppressed by the UT antagonist SB-611812
(Bousette et al., 2006b). In these cells, UII promotes
transforming growth factor-b1 (TGF-b1) expression and
UII-induced collagen synthesis is blocked by a TGF-b1
neutralizing antibody (Dai et al., 2007), indicating that
TGF-b1 mediates the profibrotic effects of UII. Alto-
gether, these observations give credence to the notion
that UII plays a role in tissue remodeling associated
with cardiovascular diseases.
2. Regulation of Vascular Tone. Initial studies of
UII demonstrated a potent vasoconstrictor activity
on isolated arteries from fish, birds, and mammals
(Muramatsu and Kobayashi, 1979; Gibson et al., 1986;
Bottrill et al., 2000) (Fig. 16). Similarly, UII causes
vasoconstriction on human coronary, mammary, and
radial arteries with their endothelia removed (Maguire
et al., 2000; Paysant et al., 2001). In an in vivo study in
human subjects, Böhm and Pernow (2002) observed
potent vasoconstrictor activity upon local administra-
tion of UII. However, a great amount of heterogeneity of
vasoactive responses to UII has been observed among
vascular beds from different species, as well as different
regions within the same species (Medakovic et al., 1975;
Douglas et al., 2000b; Camarda et al., 2002b). Potent
vasodilation in response to UII has been frequently
observed (Gibson, 1987; Stirrat et al., 2001). Interest-
ingly, in a review by Desai et al. (2008) it is suggested
that the vasoactivity of UII is dependent on blood vessel
diameter: smaller arteries of 0.07 mm in diameter,
whose responses are thought to be more endothelium
mediated, vasodilate in response to UII, whereas arteries
0.07–0.25 mm in diameter show a more attenuated
response and large vessels with a 0.25 mm diameter,
whose responses are thought to be more smooth muscle
mediated, show no response (MacLean et al., 2000;
244 Vaudry et al.
Stirrat et al., 2001; Bennett et al., 2004). However,
another study reports that UII has no vasoconstrictor
action in human arteries and veins of varying calibers
from different vascular beds (Hillier et al., 2001). The
absence of effect of UII on forearm resistance vessels has
been confirmed in vivo (Wilkinson et al., 2002; Cheriyan
et al., 2009). Properties of the signal transduction cascade
of the UT receptor system could be contributing to the
differential vasoactive effects of UII (see section III.B).
When the UII peptide binds UT in vascular smooth muscle
cells, this leads to dissociation of the abg-G protein com-
plex and activation of Ga
q/11
. The activated Ga
q/11
causes
the PLC-mediated hydrolysis of phosphatidylinositol-4-5
bisphosphate into IP
3
and diacylglycerol. IP
3
can then
bind to its receptors on endoplasmic/sarcoplasmic retic-
ula, causing the increase in intracellular Ca
2+
underlying
contraction (see section III.B). In the endothelium-mediated
vasodilation caused by UII, UT activation on the endothe-
lium leads to the release of NO and endothelium-derived
hyperpolarizing factor, causing vasodilation (McDonald
et al., 2007). Differences in expression of UT in vessels
of different sizes and locations may also contribute
to the variability in response to UII (Onan et al.,
2004a). Interestingly, through its two receptor subtypes,
endothelin-1 also mediates endothelium-independent
vasoconstriction and endothelium-dependent vasocon-
striction (Maguire et al., 2000). Despite being the most
potent vasoconstrictor, UII is often described as having
the most variable responses (Russell and Molenaar, 2004)
and the least efficacy compared with other vasoconstrictors
such as endothelin-1, angiotensin II, and noradrenaline
(Douglas et al., 2000a; Maguire et al., 2000; Camarda
et al., 2002b). Finally, URP has been demonstrated to be
a less potent vasoconstrictor (Chatenet et al., 2004) and
vasodilator (Prosser et al., 2006) than UII in rat, despite
having the same binding affinity to the UT receptor.
The action of UII on vascular tone has also been
explored in submammalian vertebrates. In the bullfrog
Fig. 16. Effect of UII and other vasoactive agents on isolated descending rat aorta. Human UII provokes a concentration-dependent contraction of aortic rings.
(A) Representative experimental traces illustrating the contractile responses of aortic rings from three separate rats upon exposure to 10 nM UII. Contraction
was sustained and tone did not return to basal levels for .30 minutes after removal of peptide from the organ bath. Also evident are the cyclical changes in
tone frequency observed upon (a) addition or (b) removal of UII to or from [or both (c)] the organ bath. (B) Human UII was both efficacious and potent compared
with [Arg
8
]vasopressin, angiotensin II, and prostaglandin PGF
2a
.[ReprintedfromDouglasetal.(2000).Usedwithpermission.]
Urotensin II and Its Receptor 245
Rana catesbeiana, now renamed Lithobates catesbeia-
nus, UII induces a concentration-dependent contrac-
tion of vascular rings from the proximal and distal
regions of the left and right systemic arches (Yano
et al., 1995). In vivo, UII causes a marked reduction of
cardiac output that is not accompanied by a fall in
arterial blood pressure, confirming that UII increases
systemic vascular resistance (Yano et al., 1995; Conlon
et al., 1996). In vascular rings prepared from trout
celiacomesenteric and branchial arteries, UII produces
robust contractions (Le Mével et al., 1996). In un-
anesthetized trout, intra-arterial administration of UII
provokes a dose-dependent increase in arterial blood
pressure associated with a decrease in heart rate (Le
Mével et al., 1996). Collectively, these data indicate
that, in amphibians as in fish, the pressor effects of UII
are mediated predominantly by an increase in systemic
vascular resistance.
3. Regulation of Myocardial Contractility. The di-
rect effects of UII on human myocardial contractility
have been studied in strips of myocardium isolated
from human patients that were stimulated to contract
at 60 beats/min. Application of UII increases the
contractile force in the right atrium and right ventricle,
identifying UII as the most potent inotropic agent to
date, surpassing endothelin-1, serotonin, and nor-
adrenaline (Russell et al., 2001). UII displays similar
contractile activity on myocardial strips isolated from
rats (Gong et al., 2004). In vivo studies in cynomolgus
monkeys and anesthetized rats have shown that acute
systemic infusion of UII mediates a drop in mean
arterial blood pressure, which is contradictory to the
supposed positive inotropic effects of UII (Ames et al.,
1999; Hassan et al., 2005). A potential explanation for
the observed variability in contractile responses to UII
administration is that the drop in blood pressure and
contractility could be due to coronary artery constric-
tion caused by UII (Desai et al., 2008).
4. Role in Hypertension. The status of UII as the
most potent endogenous vasoconstrictor suggests a po-
tential role in essential hypertension (Krum and Kemp,
2007; Desai et al., 2008). Hypertensive patients were
found to have elevated levels of UII compared with
normotensive controls in a study by Cheung et al. (2004),
where UII was directly related to systolic blood pressure.
Hypertensive survivors of myocardial infarction also
have significantly elevated plasma UII levels after
exercise compared with similar patients without hyper-
tension (Rdzanek et al., 2006). A study by Thompson
et al. (2003) was first to measure UII concentrations in
CSF and found CSF UII levels to be lower than those
of plasma and, remarkably, found a significant positive
correlation between CSF UII concentrations and mean
arterial blood pressure. After demonstrating that URP
and UT expression are upregulated in the kidneys of rats
withchronicrenalfailureorhypertension(Morietal.,
2009), Hirose et al. (2009) went on to examine the gene
expression of UII, URP, and UT in the heart and aorta of
hypertensive rats and found an increased expression of
the entire urotensinergic system (Hirose et al., 2009).
A development in the study of the urotensinergic system
in hypertension is the study by Behm et al. (2004a)
that reports a hypertensive cat model to be useful in
monitoring classic systemic hypertensive responses and
the effects of UII administration and UT antagonism on
these parameters.
Given the accumulating evidence for a role of the
urotensinergic system in systemic hypertension, studies
have emerged on the roles in pulmonary hypertension.
On the one hand, human UII is a potent vasoconstrictor
in pulmonary arteries isolated from hypoxic rats, and
this response increases at the onset of pulmonary
hypertension (MacLean et al., 2000). On the other hand,
pulmonary arteries isolated from humans did not re-
spond to UII (MacLean et al., 2000; Stirrat et al., 2001).
Although plasma and lung concentrations of UII are
unchanged in hypoxic rats, there was an observed
pulmonary pressure-induced increase in UT expression
in the right ventricle (Zhang et al., 2002). In another rat
model of pulmonary hypertension, UII immunoreactive
staining was upregulated in endothelial cells and smooth
muscle cells of small pulmonary arteries (Qi et al., 2004).
To determine a more direct role for UT in pulmonary
hypertension, a recent study by Onat et al. (2013) used
the UT antagonist palosuran in a rat model for pul-
monary hypertension and observed significant decreases
in mean pulmonary arterial pressure, right ventricular
hypertrophy, and right ventricular myocardial infarction.
There are limitations to this study, because the palosuran
inhibitor also decreased endothelin-1 and TGF-blevels.
More selective inhibitors and further research will
continue to provide insight into the direct roles of the
urotensinergic system in pulmonary hypertension and
other cardiovascular pathologies.
5. Role in Atherosclerosis. Atherosclerosis is a lead-
ing cause of death in Western societies and is a major
contributing factor to several cardiovascular diseases.
Thus determining the role of the urotensinergic system in
atherosclerosis is a critical area of study (Pakala, 2008).
Bousette et al. (2004) were first to demonstrate that
atherosclerotic lesions of the human carotid arteries and
aorta have increased expression of UII and UT compared
with healthy vessels. More specifically, using immuno-
histochemistry, strong UII immunoreactivity was ob-
served in endothelial, smooth muscle, and inflammatory
cells, particularly in the intima, in both carotid and aortic
plaques. Using quantitative real time RT-PCR analysis,
they demonstrated that UII production mainly occurs in
leukocytes, whereas UT expression is mediated primarily
by monocytes and macrophages (Bousette et al., 2004).
This suggests that inflammatory cells play an important
role in the UT-dependent atherosclerotic function. In
a later study, the same group found elevated levels of UII
mRNA and protein in atherosclerotic coronary arteries
246 Vaudry et al.
compared with normal coronary arteries, with UII
expression being highest in endothelial cells in areas
with inflammatory or fibrofatty lesions (Hassan et al.,
2005). Similarly, in another study, UII expression was
reported to be localized to areas of macrophage in-
filtration in atherosclerotic coronary arteries (Maguire
et al., 2004). Elevated UII levels have also been observed
in human plasma of patients with atherosclerosis
(Heringlake et al., 2004; Lapp et al., 2004; Loirand
et al., 2008). UII alone and synergistically with oxidized
low-density lipoprotein (LDL) and serotonin also en-
hances vascular smooth muscle cell proliferation, a key
process for the intimal thickening stage of atherosclerosis
(Watanabe et al., 2001a,b). This is of great clinical
significance, because oxidized LDL is a major contribut-
ing factor to atherosclerotic plaque formation. Further-
more, UII has also been linked to increased foam cell
formation in atherosclerosis (Watanabe et al., 2005).
Acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1),
is a key enzyme in cholesterol homeostasis that functions
to convert intracellular free cholesterol into cholesterol
ester for storage in lipid droplets. ACAT-1 is important
in the formation of foam cells, which form early in
atherosclerotic lesions by macrophages continuously
taking up oxidized LDL via scavenger receptors. The
accumulation of these macrophage-derived foam cells
contributes to the necrotic fibrofatty cores seen in
atherosclerotic lesions (Bousette and Giaid, 2006). The
stimulating effects of UII on foam cell formation seem to
involve various intracellular signaling pathways, because
they were inhibited by selective UT antagonist urantide,
protein kinase C inhibitor rottlerin, MEK inhibitor
PD98059, Rho kinase inhibitor Y27632, c-Src protein
tyrosine kinase inhibitor PP2, and G protein inactivator
GDP-b-S (Watanabe et al., 2005). In recent years,
significant evidence has beguntoemergeabouttheroles
of the urotensinergic system in atherosclerosis by the
use of genetic inhibition and the development of new
pharmacological inhibitors. A recent study by You et al.
(2012) demonstrates that UII gene deletion in athero-
sclerotic mice, as well as the use of the UT antagonist
SB657510, ameliorates many features of atherosclerosis,
including reducing serum cytokines and adipokines,
improving aortic atherosclerosis, reducing weight gain
and fat deposition, decreasing blood pressure, and im-
proving glucose tolerance. After observing increased
UII expression in diabetes-associated atherosclerotic
mice and humans, Watson et al. (2013) demonstrated
that the same UT antagonist, SB657510, attenuated
diabetes-associated plaque development. Interestingly,
Bousette et al. (2009) observed that genetic deletion
of UT on ApoE knockout mice (a model for atheroscle-
rosis) increased atherosclerosis as well as serum insulin
and lipids in these mice. It is suggested that UT deletion
in these mice downregulates ACAT-1 expression, ulti-
mately decreasing receptor-mediated lipoprotein up-
take in the liver. This increases hyperlipidemia, decreases
hepatic steatosis and, along with UT-KO–associated
hypertension, is thought to contribute to the increase
in atherosclerosis seen in these mice. The further de-
velopment of pharmacological agents capable of in-
terfering with the urotensinergic system and their
use in animal models will contribute to a better
understanding of the roles of UII and URP in athero-
sclerosis as well as the development of novel thera-
peutic approaches.
6. Role in Heart Failure. Under physiologic con-
ditions, UII expression is strongest in the CNS but is
significantly increased in the heart in cardiovascular
disease states (Bousette and Giaid, 2006; Khan et al.,
2007). Both UII and UT expression increase signifi-
cantly in patients with end-stage congestive heart
failure (CHF), particularly in cardiomyocytes and to
a lesser extent in vascular smooth muscle cells,
endothelial cells, and inflammatory cells (Douglas et al.,
2002). There is a correlation between UII levels and
cardiac dysfunction, because the previously mentioned
study observed an inverse relationship between UII
levels and ejection fraction (Douglas et al., 2002). This
increase in UII seen in cardiac dysfunction is supported
by several studies demonstrating elevated plasma UII
levels in patients with CHF (Ng et al., 2002; Richards
et al., 2002; Russell et al., 2003) or acute myocardial
infarction (Khan et al., 2007). In studies where disease
data were separated by etiology, UII levels in plasma
increased similarly in both ischemic and nonischemic
CHF (Douglas et al., 2002; Russell et al., 2003). The
inverse relationship between UII and ejection fraction in
CHF patients is supported by additional studies by
Gruson et al. (2006). Conversely, there have also been
studies showing no difference in plasma UII in CHF
patients compared with healthy controls (Dschietzig
et al., 2002; Jołda-Mydłowska et al., 2006), potentially
due to differences in patient populations (Bousette and
Giaid, 2006). Recently, Jani et al. (2013) developed
a solid phase extraction technique such that both
plasma UII and URP can be differentially isolated and
assayed separately. Given the structural similarity
between UII and URP, this ensures the specificity of
both measurements. Using this newly developed tech-
nique, Jani et al. (2013) observed significant increases
in both UII and URP plasma levels in patients with
acute heart failure compared with healthy controls,
suggesting roles for the entire urotensinergic system in
acute heart failure. This is supported by a study by
Nakayama et al. (2008) that demonstrates an increase
in gene expression of URP, UII, and UT in the hearts of
rats with CHF.
Although there is accumulating evidence associating
plasma UII levels with cardiac dysfunction (Totsune
et al., 2001, 2004), current studies aim to elucidate
functional roles for the urotensinergic system in heart
failure. In a study by Lim et al. (2004), a noninva-
sive iontophoresis technique was used to examine the
Urotensin II and Its Receptor 247
effects of UII on cutaneous blood flow in healthy and
CHF patients. Although UII administration caused
vasodilation in healthy patients, in patients with CHF,
UII caused vasoconstriction, indicated by reduced
blood flow in skin microcirculation. Because endothe-
lial dysfunction is a common feature of CHF (Katz,
1997) and several studies have shown UII to have
differential endothelium-dependent and independent
vasoactive effects (Gibson, 1987; Lim et al., 2004), this
suggests that the functional state of the endothelium
in CHF is a critical consideration in determining the
effect of the urotensinergic system in CHF. Using
selective UT receptor antagonist SB-611812 in rats
after coronary artery ligation, Bousette et al. (2006a)
demonstrated significantly improved cardiac dysfunc-
tion. Specifically, blocking UT led to decreases in left
ventricular end diastolic pressure, lung edema, right
ventricular systolic pressure, central venous pressure,
cardiomyocyte hypertrophy, and ventricular dilata-
tion. A subsequent study in a rat model of ischemic
CHF showed that SB-611812 administration attenu-
ates cardiac remodeling (Bousette et al., 2006b).
SB-611812–mediated UT blockage decreases myocar-
dial fibrillar collagen deposition and leads to a reduced
ratioofcollagentype1totypeIII(Bousetteetal.,
2006b), which has been previously linked to decreased
diastolic dysfunction (Nishikawa et al., 2001). This is
consistent with previous work demonstrating the
fibrotic effects of UII in vitro and in vivo. Tzanidis
et al. (2003) demonstrated that incubation of cardiac
fibroblasts with UII leads to increased expression of
fibronectin, type I and type III procollagen mRNAs,
and significant collagen peptide synthesis upon over-
expression of recombinant UT. This suggests that the
fibrotic role of UII in myocardial remodeling would be
enhanced in diseased states where increased UT has
been repeatedly demonstrated (Russell, 2004). There
is an increasing amount of evidence implicating UII
in cardiac hypertrophy. Overexpression of UII and UT
in rat cardiomyocytes increases cardiomyocyte growth
(Zou et al., 2001), enhances sarcomere organization
(Zou et al., 2001) and produces a hypertrophic pheno-
type (Tzanidis et al., 2003; Onan et al., 2004b). In
addition to demonstrating UII-mediated hypertrophic
effects, Johns et al. (2004) found that UII-stimulated
cardiac myocytes secreted inflammatory cytokine IL-6,
suggesting a potential proinflammatory role for UII in
heart failure.
C. Effect of Urotensin II/Urotensin II–Related Peptide
on the Urogenital Tract
The fact that UII is produced and released by human
(Nothacker et al., 1999; Shenouda et al., 2002; Matsushita
et al., 2003) and monkey kidney (Elshourbagy et al.,
2002), the expression of UT mRNA in the rat kidney (Song
et al., 2006a) and the presence of [
125
I]UII binding sites in
the human (Maguire et al., 2000), cat (Aiyar et al., 2005),
and rat kidney (Disa et al., 2006) indicate that the
urotensinergic system may be implicated in physiologic
regulation of renal function and/or renal pathology.
Indeed, UII infusion causes a marked reduction in
glomerular filtration rate, urine flow, and sodium excre-
tion rate (Abdel-Razik et al., 2008). UII immunoreactivity
is present in the glomerular basement membrane, glo-
merular mesangium, and Bowman capsule of children
with membranoproliferative glomerulonephritis and mem-
branous glomerulonephritis. In the kidney of diabetic
patients, UII and UT gene expression are markedly
increased (Langham et al., 2004). UII and UT mRNA
levels are also significantly elevated in the kidney medulla
of SHR, and the effects of UII on renal blood flow and
glomerular filtration rate are stronger in SHR than in
WKY (Abdel-Razik et al., 2008), supporting a role for UII
in renal pathophysiology.
The URP gene is overexpressed in a mouse model of
obstructive nephropathy called “megabladder,”which
results from lack of bladder smooth muscle differenti-
ation (Singh et al., 2008), suggesting that URP may
play a critical role in bladder smooth muscle development.
In frog, UII produces a concentration-dependent increase
in the frequency of contraction of bladder strips (Yano
et al., 1994). Similarly, in trout, UII induces a spasmosgenic
action on the urinary bladder (Lederis, 1970).
The UII gene is expressed in the human corpus
cavernosum (HCC), and UT is present in endothelial
cells of HCC (d’Emmanuele di Villa Bianca et al., 2010).
In rat, intracavernous injection of UII causes an in-
crease in intracavernous pressure without affecting
systemic blood pressure (d’Emmanuele di Villa Bianca
et al., 2010). In HCC tissue, UII causes an endothelium-
dependent relaxation involving the NO pathway (Bianca
et al., 2012). These observations suggest that the UII/UT
system may represent a novel therapeutic target to treat
erectile dysfunction.
D. Effect of Urotensin II/Urotensin II–Related Peptide
on the Gastrointestinal Tract
The genes encoding UII and/or URP mRNAs are
expressed in the human (Coulouarn et al., 1998; Sugo
et al., 2003; Ong et al., 2005), rat (Sugo et al., 2003), and
mouse intestine (Dubessy et al., 2008), and the UT gene is
expressed in the mouse intestine and colon (Elshourbagy
et al., 2002). UII provokes concentration-dependent con-
tractions of guinea pig ileal segments via activation of
ganglionic cholinergic neurons (Horie et al., 2003). The
contractile response is blocked by cyclooxygenase and
phospholipase A
2
inhibitors (Horie et al., 2005), in-
dicating that the effect of UII on myenteric neurons is
mediated through prostaglandin biosynthesis. Moreover,
UII potently relaxes the mouse anococcygeus muscle
(Gibson et al., 1984), suggesting that UII may play
a role in the control of defecation.
In isolated bullfrog longitudinal ileal strips, UII
provokes a concentration-dependent increase in the
248 Vaudry et al.
frequency and strength of contractions (Yano et al.,
1994). Pretreatment of the tissues with indometh-
acin significantly reduces the response to UII (Yano
et al., 1994), indicating that prostaglandins mediate the
spasmogenic action of UII in the frog ileum. The ability
of UII to induce contractions of the fish hindgut has
been exploited to set up bioassays that have been used
successfully to monitor chromatographic separation of
fish UII (Zelnik and Lederis, 1973; Chan et al., 1978;
Pearson et al., 1980). Thus, purified UII fractions from
Catostomus commersonii (Zelnik and Lederis, 1973) or
Gillichthys mirabilis urophysial extracts (Chan et al.,
1978) induce contractions of trout rectal strips in a
concentration-dependent manner.
In addition to its spasmogenic action, UII stimulates the
transport of sodium and chloride ions across the goby
posterior intestinal epithelium (Loretz, 1990; Loretz et al.,
1983, 1985), lowers [Ca
2+
]
i
in isolated goby enterocytes
(Loretz and Assad, 1986), and increases water absorption
in intestinal sacs from seawater-adapted tilapia (Mainoya
and Bern, 1982). Electrophysiological studies indicate that
UII exerts a dual effect on the isolated posterior intestine
of freshwater-adapted European eel Anguilla anguilla:UII
reduces short-circuit current and transepithelial potential
difference at concentrations ranging from 10 to 100 nM
and increases these parameters at a concentration of
500 nM (Baldisserotto and Mimura, 1997). Altogether,
these observations substantiate a role of UII in osmoreg-
ulationinfish.
E. Effect of Urotensin II/Urotensin II–Related Peptide
on the Pancreas
The UT gene is expressed in the human (Ames et al.,
1999; Douglas and Ohlstein, 2000), monkey, and mouse
pancreas (Elshourbagy et al., 2002). The UII gene is also
expressed in the human and rat pancreas (Coulouarn
et al., 1998; Ames et al., 1999; Sugo et al., 2003), and the
evidence of the presence of the UII peptide has been
found in a rat pancreas extract by reversed-phase HPLC
analysis combined with radioimmunoassay detection
(Silvestre et al., 2004), suggesting that UII may control
pancreatic activity. The effect of UII on the endocrine
pancreas has been studied using an in situ perfused rat
pancreas model (Silvestre et al., 1986). It was first
observed that synthetic frog UII, at doses of 10 and
100 nM, significantly reduces glucose-evoked insulin re-
lease but does not affect glucagon and somatostatin
secretion (Silvestre et al., 2001). Frog UII also inhibits
the insulin response to arginine (Silvestre et al., 2001).
It was subsequently shown that rat UII provokes a
concentration-dependent inhibition of glucose-induced
insulin secretion with an IC
50
of 0.12 nM (Silvestre
et al., 2004, Liu and Zhu, 2010). Rat UII also attenuates
insulin secretion elicited by various secretagogues that
act on pancreatic b-cells through diverse signaling path-
ways (Silvestre et al., 2004, 2009). Thus, UII inhibits
the insulin response to the cholinergic agonist carbachol
that activates polyphosphoinositide turnover (Gilon and
Henquin, 2001), glucagon-like peptide-1 that stimulates
the adenylyl cyclase/cyclic AMP pathway (Delmeire
et al., 2003), the dihydropyridine BAY K 8644 that
induces Ca
2+
influx through L-type Ca
2+
channels (Hess
et al., 1984), and the sulfonylurea tolbutamide that
closes ATP-dependent K
+
channels (Henquin et al.,
1992). Consistent with these observations, it was pre-
viously reported that the insulinostatic effect of somato-
statin could be ascribed both to decreased formation of
cyclic adenosine monophosphate (Sharp, 1996) and
inhibition of the intracellular Ca
2+
response to various
insulin secretagogues (Nilsson et al., 1989). The in-
hibitory effect of UII on glucose-induced insulin secre-
tion is blocked by the UT antagonists palosuran and
urantide but not by a somatostatin antagonist (Marco
et al., 2008). Reciprocally, palosuran does not reverse
the insulinostatic effect of somatostatin (Marco et al.,
2008). Interestingly, both palosuran and urantide potenti-
ate glucose-evoked insulin release, indicating that endoge-
nous UII exerts a tonic inhibitory action upon b-cell
secretory activity (Marco et al., 2008).
Elevated UII levels have been detected in the plasma
of diabetic patients (Totsune et al., 2003, 2004; Krum
and Gilbert, 2003; Suguro et al., 2008), particularly in
individuals presenting with metabolic syndrome (Ong
et al., 2008; Oguri et al., 2009; Gruson et al., 2010b).
In addition, overexpression of UII and UT has been
reported in the kidney of diabetic patients (Langham
et al., 2004). The UII and UT genes are upregulated in
both the aorta and kidney of nonobese diabetic rats
(Tian et al., 2008; Xie and Liu, 2009). Genetic studies
have shown that single nucleotide polymorphisms
(SNPs) in the UII gene are associated with type 2
diabetes mellitus (T2DM) in the Northern Chinese (Sun
et al., 2002, Zhu et al., 2002; Tan et al., 2006), Hong
Kong Chinese (Ong et al., 2006), Japanese (Wenyi et al.,
2003; Suzuki et al., 2004), Turkish (Okumus et al.,
2012), and Spanish populations (Sáez et al., 2011). In
particular, the SNP 3836C→T (S89N) found in the
Japanese and Hong Kong populations has been associ-
ated with elevated plasma UII level, higher plasma
insulin, insulin resistance, and susceptibility of de-
veloping T2DM (Wenyi et al., 2003; Suzuki et al., 2004;
Ong et al., 2006). SNPs have also been reported in the
UT promoter in the Japanese population, but no
significant association with T2DM was found (Suzuki
et al., 2004). In bovine, 5 SNPs have been identified for
the UII gene and 14 SNPs for the UT gene, and
a significant association with fat deposition and fatty
acid composition was reported (Jiang et al., 2008). In the
coho salmon Oncorhynchus kisutch, UII enhances glucose
mobilization, increases liver glucose-G-phosphatase ac-
tivity, and stimulates glycogene synthetase activity
(Sheridan et al., 1987).
The genetic association between SNPs in the UII gene
andT2DMsuggeststhatUTantagonistsmayhave
Urotensin II and Its Receptor 249
beneficial effects for the treatment of diabetes and
metabolic syndrome. As a matter of fact, treatment of
streptozotocin-induced diabetic rats with palosuran
(Clozel et al., 2004) improves survival, increases serum
insulin concentration, reduces glycemia, attenuates
albuminuria, and prevents renal tubular degeneration
(Clozel et al., 2006). However, clinical trials led to
divergent results (Desai et al., 2008; Tsoukas et al.,
2011). One study indicates that, in hypertensive T2DM
patients affected by nephropathy, palosuran (125 mg
twice daily) reduces albuminuria, suggesting that block-
age of UT could be a therapeutic approach for the
treatment of diabetic nephropathy (Sidharta et al.,
2006). However, the authors subsequently found that
palosuran does not improve insulin secretion, insulin
sensitivity, and glycemia in T2DM (Sidharta et al.,
2009). In addition, Clozel et al. (2006) conducted a
series of three clinical proof-of-concept studies in
diabetic nephropathy patients that did not reveal
major efficacy of palosuran at a relatively high dose
(300 mg/kg per day). The lack of effect of palosuran on
albuminuria, blood pressure, glomerular filtration rate,
and renal plasma flow in patients with T2DM nephrop-
athy was recently confirmed by the PROLONG study
group (Vogt et al., 2010).
F. Effect of Urotensin II/Urotensin II–Related Peptide
on the Liver
The liver is a documented site of UII and URP
production in human (Coulouarn et al., 1998; Sugo
et al., 2003) and sheep (Charles et al., 2005). In
cirrhotic bile duct–ligated rats, increased expression
of UII and UT is observed in hepatic tissue and portal
veins (Trebicka et al., 2008). In cirrhotic patients,
plasma UII concentration is elevated in the hepatic
vein compared with the hepatic portal vein (Heller
et al., 2002). Patients with chronic liver disease exhibit
high serum UII levels that are associated with the
severity of the disease and the extent of portal hyperten-
sion (Kemp et al., 2007). The expression of UT mRNA and
UT protein is also significantly increased in the liver of
patients with cirrhosis and portal hypertension (Liu
et al., 2010a). Taken together, these observations in-
dicate that the liver is a source of UII production, par-
ticularly in pathophysiological conditions, and that the
urotensinergic system may play a role in cirrhosis and
portal hypertension.
G. Effect of Urotensin II/Urotensin II–Related Peptide
on the Adrenal Gland
Intracerebroventricular injection of UII significantly
increases plasma levels of adrenaline, ACTH, and cortisol
in unanesthetized sheep (Watson et al., 2003) and
corticosterone in rat (Watson et al., 2008). Expression of
UII mRNA, but not URP mRNA, has been observed in
the mouse and rat adrenal gland (Sugo et al., 2003;
Dubessy et al., 2008) and in human adrenocortical and
adrenomedullary tissues (Takahashi et al., 2003; Zeng
et al., 2006; Giuliani et al., 2009). Genome-wide micro-
array experiments have shown that the UII gene is
downregulated in the adrenal gland of SHR, stroke-prone
SHR, and malignant stroke-prone SHR (Ashenagar et al.,
2010). Expression of UT mRNA has also been reported in
the mouse and monkey adrenal gland (Elshourbagy et al.,
2002) and in human adrenal tissue (Takahashi et al.,
2003; Zeng et al., 2006; Giuliani et al., 2009). Immuno-
histochemical experiments have also shown the presence
of the UII peptide in the human adrenal medulla
(Morimoto et al., 2008). UII and UT mRNAs are both
present in freshly dispersed and cultured rat adrenocor-
tical cells (Albertin et al., 2006). These observations
suggest that UII may act as a paracrine factor, produced
either by the adrenal cortex or the adrenal medulla,
regulating corticosteroid secretion. In agreement with
this hypothesis, UII induces a concentration-dependent
inhibition of basal corticosterone secretion from cultured
rat adrenocortical cells but does not affect ACTH-evoked
corticosterone secretion (Albertin et al., 2006).
The UII and UT genes are expressed in cortisol-
producing adenoma, aldosterone-producing adenoma,
carcinoma, and pheochromocytoma (Takahashi et al.,
2001, 2003; Zeng et al., 2006). UII and UT mRNAs are
also expressed in PC12 rat pheochromocytoma cells
(Aita et al., 2010). The presence of the UII peptide
and UT protein has been confirmed in human adre-
nocortical and adrenomedullary tumors by immuno-
blot analysis and immunohistochemistry (Takahashi
et al., 2001; Morimoto et al., 2008; Giuliani et al.,
2009). Consistent with these data, UII stimulates
proliferation of human adrenocortical carcinoma cells
(Takahashi et al., 2003) and pheochromocytoma cells
(Zeng et al., 2006; Aita et al., 2010) in a concentration-
dependent manner.
In the frog Pelophylax ridibundus, UII has no effect
on corticosterone and aldosterone secretion from peri-
fused interrenal tissue. In addition, UII does not modify
ACTH- and angiotensin II–induced corticosteroid secre-
tion (Feuilloley et al., 1994). In rainbow trout and
European flounder, UII stimulates cortisol secretion
in vitro by perifused interrenal tissue derived from
seawater-adapted fish but does not affect cortisol
secretion in tissue derived from freshwater-adapted
fish (Arnold-Reed and Balment, 1994; Kelsall and
Balment, 1998). In vivo, intra-arterial infusion of UII
in seawater-adapted flounder causes a dose-dependent
increase in plasma cortisol levels (Kelsall and Balment,
1998).
V. Conclusions and Perspectives
Since the discovery 15 years ago of the potent
vasoconstrictor and biologic effects of UII, substantial
research has been performed to understand the role of
UII in human physiology and pathophysiology. Toward
250 Vaudry et al.
this goal, high affinity and selective peptidic and
nonpeptidic receptor agonists and antagonists have
been developed to further elucidate the pharmacology
and biology of UII. Clearly, because of their physi-
ochemical and pharmacokinetic properties, nonpepti-
dic UII antagonists are attractive alternatives to
peptidic antagonists, and they offer the opportunity
to evaluate the role of UII in chronic disorders. These
pharmacological tools have been employed to explore
the role of endogenous UII in pathophysiology. The
most studied clinical indications include hypertension,
heart failure, renal disease, atherosclerosis, asthma,
pulmonary hypertension, and diabetes. Although these
compounds have been studied in a variety of preclinical
animal models with encouraging results, UT antago-
nists have yet to be systematically and comprehensively
studied in human diseases (Gilbert et al., 2004). There
is still a paucity of human investigation with UT
antagonists, and the clinical studies that have been
conducted have not fully clarified the understanding
of the role of UII in human pathophysiology.
For example, a clinical study by Vogt et al. (2010)
examined the effects of the UT antagonist palosuran
in hypertensive patients with diabetic nephropathy.
Contrary to preclinical data, a 4-week treatment of
subjects with palosuran did not affect blood pressure,
glomerular filtration rate, renal hemodynamics, or
albuminuria. Hence, these results do not support a role
of UII in the control of blood pressure or renal function
in patients with diabetic nephropathy. Also, the UT
antagonist GSK1440115 was tested recently in a phase
1B clinical study in asthma patients. Again, contrary
to preclinical data, acute UT antagonism did not in-
duce bronchodilation or protect against methacholine-
induced bronchospasm (Portnoy et al., 2013). This
clinical study suggested that antagonism of UII is not
likely to provide benefit as an acute bronchodilator in
asthmatic patients. In addition, there are contradictory
results in the literature on effects of exogenously
administered UII on cardiovascular function, as well
as regional differences in the vasoconstrictor response
to UII. Moreover, vasopressor effects of UII may have
differential cardiovascular consequences depending on
the disease state. Clearly, more work needs to be per-
formed, because clinical research has not revealed an
unambiguous role of UII in human disease.
Despite UII being recognized as the most potent
vasoconstrictor identified so far, a definitive role for
UII in cardiovascular disease is still under investi-
gation. The major challenge for the future will be
clinical demonstration of efficacy of receptor antago-
nists in human pathophysiology, and then UT may
emerge as an important therapeutic target. Phar-
macological intervention through the now currently
orally active UT antagonists will help provide a ra-
tional approach to understanding the role of UII in
pathophysiology.
Acknowledgments
The authors thank J. Michael Conlon (Faculty of Medicine and
Health Science, UAE University, United Arab Emirates), Jean-
Claude do Rego (Institut National de la Santé et de la Recherche
Médicale U905, Institute for Research and Innovation in Biomedi-
cine, University of Rouen, France), and Dan Larhammar (Depart-
ment of Neuroscience, Uppsala University, Sweden) for valuable
discussion, and Catherine Beau for skillful secretarial assistance.
The authors dedicate this review to Howard A. Bern, the “father”of
urotensin II, who died in 2012, and to Stephen A. Douglas, who died
in 2009, for his enormous contribution to the elucidation of the
pathophysiological roles of urotensin II.
Authorship Contributions
Wrote or contributed to the writing of the manuscript: H. Vaudry,
Leprince, Chatenet, Fournier, Lambert, Le Mével, Ohlstein, Schwertani,
Tostivint, D. Vaudry.
References
Abdel-Razik AE, Balment RJ, and Ashton N (2008) Enhanced renal sensitivity of the
spontaneously hypertensive rat to urotensin II. Am J Physiol Renal Physiol 295:
F1239–F1247.
Aita Y, Kasahara T, Isobe K, Kawakami Y, and Takekoshi K (2010) Effect of uro-
tensin II on PC12 rat pheochromocytoma cells. J Neuroendocrinol 22:83–91.
Aiyar N, Johns DG, Ao Z, Disa J, Behm DJ, Foley JJ, Buckley PT, Sarau HM, van-der-
Keyl HK, Elshourbagy NA, et al. (2005) Cloning and pharmacological characteriza-
tion of the cat urotensin-II receptor (UT). Biochem Pharmacol 69:1069–1079.
Albertin G, Casale V, Ziolkowska A, Spinazzi R, Malendowicz LK, Rossi GP,
and Nussdorfer GG (2006) Urotensin-II and UII-receptor expression and function
in the rat adrenal cortex. Int J Mol Med 17:1111–1115.
Albertin G, Guidolin D, Sorato E, Oselladore B, Tortorella C, and Ribatti D (2011)
Urotensin-II-stimulated expression of pro-angiogenic factors in human vascular
endothelial cells. Regul Pept 172:16–22.
Albertin G, Guidolin D, Sorato E, Spinazzi R, Mascarin A, Oselladore B, Montopoli
M, Antonello M, and Ribatti D (2009) Pro-angiogenic activity of Urotensin-II on
different human vascular endothelial cell populations. Regul Pept 157:64–71.
Alexander SP, Mathie A, and Peters JA(2011) Guide to receptors and channels
(GRAC), 5th edition. Br J Pharmacol 164:S1–S324.
Altenburger JM, Fossey V, Galtier D, and Petit F (2009) inventors, Sanofi Aventis,
assignee. 5,6-Bisaryl-2-pyridinecarboxamide and 5,6-bisaryl-2-pyrazinecarboxamide
derivatives, their preparation and their therapeutic application as urotensin II re-
ceptor antagonists. Patent WO 2009-115665. 2009 Sep 24.
Altenburger A, Fossey V, Lassalle G, Petit F, and Vernières JC (2008) inventors,
Sanofi Aventis, assignee. 5,6-Bisaryl-2-pyridinecarboxamide derivatives, their
preparation and their therapeutic application as urotensin II receptor antagonists.
Patent FR 2904827. 2008 Feb 15.
Altenburger JM, Fossey V, and Petit F (2011) inventors, Sanofi Aventis, assignee.
Derivates of 5,6-.isaryl-2-pyrimidinecarboxamide, their preparation and their
therapeutic use as urotensin II receptor antagonists. Patent WO 2011/007090.
2011 Jan 20.
Ames RS, Sarau HM, Chambers JK, Willette RN, Aiyar NV, Romanic AM, Louden
CS, Foley JJ, Sauermelch CF, Coatney RW, et al. (1999) Human urotensin-II is
a potent vasoconstrictor and agonist for the orphan receptor GPR14. Nature 401:
282–286.
Arnold-Reed DE and Balment RJ (1994) Peptide hormones influence in vitro in-
terrenal secretion of cortisol in the trout, Oncorhynchus mykiss. Gen Comp
Endocrinol 96:85–91.
Artenstein AW and Opal SM (2011) Proprotein convertases in health and disease.
N Engl J Med 365:2507–2518.
Ashenagar MS, Tabuchi M, Kinoshita K, Ooshima K, Niwa A, Watanabe Y, Yoshida
M, Shimada K, Yasunaga T, Yamanishi H, et al. (2010) Gene expression in the
adrenal glands of three spontaneously hypertensive rat substrains. Mol Med Rep 3:
213–222.
Baghdoyan HA, Monaco AP, Rodrigo-Angulo ML, Assens F, McCarley RW,
and Hobson JA (1984) Microinjection of neostigmine into the pontine reticular
formation of cats enhances desynchronized sleep signs. J Pharmacol Exp Ther 231:
173–180.
Balat A, Karakök M, Yilmaz K, and Kibar Y (2007) Urotensin-II immunoreactivity in
children with chronic glomerulonephritis. Ren Fail 29:573–578.
Baldisserotto B and Mimura OM (1997) Changes in the electrophysiological
parameters of the posterior intestine of Anguilla anguilla (Pisces) induced by
oxytocin, urotensin II and aldosterone. Braz J Med Biol Res 30:35–39.
Barrette PO and Schwertani AG (2012) A closer look at the role of urotensin II in the
metabolic syndrome. Front Endocrinol (Lausanne) 3:165.
Batuwangala MS, Calo G, Guerrini R, Ng LL, McDonald J, and Lambert DG (2009a)
Desensitisation of native and recombinant human urotensin-II receptors. Naunyn
Schmiedebergs Arch Pharmacol 380:451–457.
Batuwangala M, Camarda V, McDonald J, Marzola E, Lambert DG, Ng LL, Calo’G,
Regoli D, Trapella C, Guerrini R, et al. (2009b) Structure-activity relationship
study on Tyr9 of urotensin-II(4-11): identification of a partial agonist of the UT
receptor. Peptides 30:1130–1136.
Behm DJ, Doe CP, Johns DG, Maniscalco K, Stankus GP, Wibberley A, Willette RN,
and Douglas SA (2004a) Urotensin-II: a novel systemic hypertensive factor in the
cat. Naunyn Schmiedebergs Arch Pharmacol 369:274–280.
Urotensin II and Its Receptor 251
Behm DJ, Herold CL, Camarda V, Aiyar NV, and Douglas SA (2004b) Differential
agonistic and antagonistic effects of the urotensin-II ligand SB-710411 at rodent
and primate UT receptors. Eur J Pharmacol 492:113–116.
Behm DJ, Herold CL, Ohlstein EH, Knight SD, Dhanak D, and Douglas SA (2002)
Pharmacological characterization of SB-710411 (Cpa-c[D-Cys-Pal-D-Trp-Lys-Val-
Cys]-Cpa-amide), a novel peptidic urotensin-II receptor antagonist. Br J Phar-
macol 137:449–458.
Behm DJ, Stankus G, Doe CP, Willette RN, Sarau HM, Foley JJ, Schmidt DB,
Nuthulaganti P, Fornwald JA, Ames RS, et al. (2006) The peptidic urotensin-II
receptor ligand GSK248451 possesses less intrinsic activity than the low-efficacy
partial agonists SB-710411 and urantide in native mammalian tissues and
recombinant cell systems. Br J Pharmacol 148:173–190.
Bennett RT, Jones RD, Morice AH, Smith CF, and Cowen ME (2004) Vasoconstrictive
effects of endothelin-1, endothelin-3, and urotensin II in isolated perfused human
lungs and isolated human pulmonary arteries. Thorax 59:401–407.
Bern HA, Pearson D, Larson BA, and Nishioka RS (1985) Neurohormones from fish
tails: the caudal neurosecretory system. I. “Urophysiology”and the caudal neuro-
secretory system of fishes. Recent Prog Horm Res 41:533–552.
Bhaskaran R, Arunkumar AI, and Yu C (1994) NMR and dynamical simulated
annealing studies on the solution conformation of urotensin II. Biochim Biophys
Acta 1199:115–122.
Bianca Rd, Mitidieri E, Fusco F, D’Aiuto E, Grieco P, Novellino E, Imbimbo C, Mirone
V, Cirino G, and Sorrentino R (2012) Endogenous urotensin II selectively modu-
lates erectile function through eNOS. PLoS ONE 7:e31019.
Böhm F and Pernow J (2002) Urotensin II evokes potent vasoconstriction in humans
in vivo. Br J Pharmacol 135:25–27.
Boivin S, Guilhaudis L, Milazzo I, Oulyadi H, Davoust D, and Fournier A (2006)
Characterization of urotensin-II receptor structural domains involved in the rec-
ognition of U-II, URP, and urantide. Biochemistry 45:5993–6002.
Boivin S, Ségalas-Milazzo I, Guilhaudis L, Oulyadi H, Fournier A, and Davoust D
(2008) Solution structure of urotensin-II receptor extracellular loop III and char-
acterization of its interaction with urotensin-II. Peptides 29:700–710.
Bottrill FE, Douglas SA, Hiley CR, and White R (2000) Human urotensin-II is an
endothelium-dependent vasodilator in rat small arteries. Br J Pharmacol 130:
1865–1870.
Boucard AA, Sauvé SS, Guillemette G, Escher E, and Leduc R (2003) Photolabelling
the rat urotensin II/GPR14 receptor identifies a ligand-binding site in the fourth
transmembrane domain. Biochem J 370:829–838.
Bousette N and Giaid A (2006) Urotensin-II and cardiovascular diseases. Curr
Hypertens Rep 8:479–483.
Bousette N, D’Orleans-Juste P, Kiss RS, You Z, Genest J, Al-Ramli W, Qureshi ST,
Gramolini A, Behm D, Ohlstein EH, et al. (2009) Urotensin II receptor knockout
mice on an ApoE knockout background fed a high-fat diet exhibit an enhanced
hyperlipidemic and atherosclerotic phenotype. Circ Res 105:686–695, 19, 695.
Bousette N, Hu F, Ohlstein EH, Dhanak D, Douglas SA, and Giaid A (2006a)
Urotensin-II blockade with SB-611812 attenuates cardiac dysfunction in a rat
model of coronary artery ligation. J Mol Cell Cardiol 41:285–295.
Bousette N, Patel L, Douglas SA, Ohlstein EH, and Giaid A (2004) Increased ex-
pression of urotensin II and its cognate receptor GPR14 in atherosclerotic lesions of
the human aorta. Atherosclerosis 176:117–123.
Bousette N, Pottinger J, Ramli W, Ohlstein EH, Dhanak D, Douglas SA, and Giaid A
(2006b) Urotensin-II receptor blockade with SB-611812 attenuates cardiac
remodeling in experimental ischemic heart disease. Peptides 27:2919–2926.
Brailoiu E, Brailoiu GC, Miyamoto MD, and Dun NJ (2003) The vasoactive peptide
urotensin II stimulates spontaneous release from frog motor nerve terminals. Br J
Pharmacol 138:1580–1588.
Brailoiu E, Jiang X, Brailoiu GC, Yang J, Chang JK, Wang H, and Dun NJ (2008)
State-dependent calcium mobilization by urotensin-II in cultured human endo-
thelial cells. Peptides 29:721–726.
Brazeau P, Vale W, Burgus R, Ling N, Butcher M, Rivier J, and Guillemin R (1973)
Hypothalamic polypeptide that inhibits the secretion of immunoreactive pituitary
growth hormone. Science 179:77–79.
Brkovic A, Hattenberger A, Kostenis E, Klabunde T, Flohr S, Kurz M, Bourgault S,
and Fournier A (2003) Functional and binding characterizations of urotensin
II-related peptides in human and rat urotensin II-receptor assay. J Pharmacol Exp
Ther 306:1200–1209.
Bruzzone F, Cervetto C, Mazzotta MC, Bianchini P, Ronzitti E, Leprince J, Diaspro A,
Maura G, Vallarino M, Vaudry H, et al. (2010) Urotensin II receptor and acetylcho-
line release from mouse cervical spinal cord nerve terminals. Neuroscience 170:67–77.
Bucharles C, Bizet P, Arthaud S, Arabo A, Leprince J, Lefranc B, Cartier D, Anouar
Y, and Lihrmann I (2014) Concordant localization of functional urotensin II and
urotensin II-related peptide binding sites in the rat brain: Atypical occurrence close
to the fourth ventricle. J Comp Neurol 522:2634–2649.
Camarda V, Guerrini R, Kostenis E, Rizzi A, Calò G, Hattenberger A, Zucchini M,
Salvadori S, and Regoli D (2002a) A new ligand for the urotensin II receptor. Br J
Pharmacol 137:311–314.
Camarda V, Rizzi A, Calò G, Gendron G, Perron SI, Kostenis E, Zamboni P, Mascoli
F, and Regoli D (2002b) Effects of human urotensin II in isolated vessels of various
species; comparison with other vasoactive agents. Naunyn Schmiedebergs Arch
Pharmacol 365:141–149.
Camarda V, Song W, Marzola E, Spagnol M, Guerrini R, Salvadori S, Regoli D,
Thompson JP, Rowbotham DJ, Behm DJ, et al. (2004) Urantide mimics urotensin-
II induced calcium release in cells expressing recombinant UT receptors. Eur J
Pharmacol 498:83–86.
Camarda V, Spagnol M, Song W, Vergura R, Roth AL, Thompson JP, Rowbotham DJ,
Guerrini R, Marzola E, Salvadori S, et al. (2006) In vitro and in vivo pharmacological
characterization of the novel UT receptor ligand [Pen5,DTrp7,Dab8]urotensin II(4-11)
(UFP-803). Br J Pharmacol 147:92–100.
Carotenuto A, Auriemma L, Merlino F, Yousif AM, Marasco D, Limatola A, Campiglia
P, Gomez-Monterrey I, Santicioli P, Meini S, et al. (2014) Lead optimization of P5U
and urantide: discovery of novel potent ligands at the urotensin-II receptor. JMed
Chem 57:5965–5974.
Carotenuto A, Grieco P, Campiglia P, Novellino E, and Rovero P (2004a) Unraveling
the active conformation of urotensin II. J Med Chem 47:1652–1661.
Carotenuto A, Grieco P, Novellino E, and Rovero P (2004b) Urotensin-II receptor
peptide agonists. Med Res Rev 24:577–588.
Carotenuto A, Grieco P, Rovero P, and Novellino E (2006) Urotensin-II receptor
antagonists. Curr Med Chem 13:267–275.
Castel H, Diallo M, Chatenet D, Leprince J, Desrues L, Schouft MT, Fontaine M,
Dubessy C, Lihrmann I, Scalbert E, et al. (2006) Biochemical and functional
characterization of high-affinity urotensin II receptors in rat cortical astrocytes.
J Neurochem 99:582–595.
Chan DKO (1975) Cardiovascular and renal effects of urotensins, I and II in the eel,
Anguilla rostrata. Gen Comp Endocrinol 27:52–61.
Chan DK, Gunther R, and Bern HA (1978) The isolated trout rectum bioassay for uro-
tensin II: assessment for specificity and precision. Gen Comp Endocrinol 34:347–359.
Charles CJ, Rademaker MT, Richards AM, and Yandle TG (2005) Urotensin II: ev-
idence for cardiac, hepatic and renal production. Peptides 26:2211–2214.
Chartrel N, Conlon JM, Collin F, Braun B, Waugh D, Vallarino M, Lahrichi SL,
Rivier JE, and Vaudry H (1996) Urotensin II in the central nervous system of the
frog Rana ridibunda: immunohistochemical localization and biochemical charac-
terization. J Comp Neurol 364:324–339.
Chartrel N, Dujardin C, Anouar Y, Leprince J, Decker A, Clerens S, Do-Régo JC,
Vandesande F, Llorens-Cortes C, Costentin J, et al. (2003) Identification of 26RFa,
a hypothalamic neuropeptide of the RFamide peptide family with orexigenic ac-
tivity. Proc Natl Acad Sci USA 100:15247–15252.
Chartrel N, Leprince J, Dujardin C, Chatenet D, Tollemer H, Baroncini M, Balment
RJ, Beauvillain JC, and Vaudry H (2004) Biochemical characterization and im-
munohistochemical localization of urotensin II in the human brainstem and spinal
cord. J Neurochem 91:110–118.
Chatenet D, Dubessy C, Boularan C, Scalbert E, Pfeiffer B, Renard P, Lihrmann I,
Pacaud P, Tonon MC, Vaudry H, et al. (2006) Structure-activity relationships of
a novel series of urotensin II analogues: identification of a urotensin II antagonist.
J Med Chem 49:7234–7238.
Chatenet D, Dubessy C, Leprince J, Boularan C, Carlier L, Ségalas-Milazzo I,
Guilhaudis L, Oulyadi H, Davoust D, Scalbert E, et al. (2004) Structure-activity
relationships and structural conformation of a novel urotensin II-related peptide.
Peptides 25:1819–1830.
Chatenet D, Folch B, Feytens D, Létourneau M, Tourwé D, Doucet N, and Fournier A
(2013a) Development and pharmacological characterization of conformationally
constrained urotensin II-related peptide agonists. J Med Chem 56:9612–9622.
Chatenet D, Létourneau M, Nguyen QT, Doan ND, Dupuis J, and Fournier A (2013b)
Discovery of new antagonists aimed at discriminating UII and URP-mediated bi-
ological activities: insight into UII and URP receptor activation. Br J Pharmacol
168:807–821.
Chatenet D, Nguyen QT, Létourneau M, Dupuis J, and Fournier A (2012) Urocontrin,
a novel UT receptor ligand with a unique pharmacological profile. Biochem
Pharmacol 83:608–615.
Chatenet D, Nguyen TT, Létourneau M, and Fournier A (2013c) Update on the
urotensinergic system: new trends in receptor localization, activation, and drug
design. Front Endocrinol (Lausanne) 3:174 10.3389/fendo.2012.00174.
Chen EW and Chiu AY (1992) Early stages in the development of spinal motor
neurons. J Comp Neurol 320:291–303.
Chen YL, Liu JC, Loh SH, Chen CH, Hong CY, Chen JJ, and Cheng TH (2008)
Involvement of reactive oxygen species in urotensin II-induced proliferation of
cardiac fibroblasts. Eur J Pharmacol 593:24–29.
Chen YH, Zhao MW, Yao WZ, Pang YZ, and Tang CS (2004) The signal transduction
pathway in the proliferation of airway smooth muscle cells induced by urotensin II.
Chin Med J (Engl) 117:37–41.
Cheriyan J, Burton TJ, Bradley TJ, Wallace SM, Mäki-Petäjä KM, Mackenzie IS,
McEniery CM, Brown J, and Wilkinson IB (2009) The effects of urotensin II and
urantide on forearm blood flow and systemic haemodynamics in humans. Br J Clin
Pharmacol 68:518–523.
Cheung BM, Leung R, Man YB, and Wong LY (2004) Plasma concentration of uro-
tensin II is raised in hypertension. J Hypertens 22:1341–1344.
Chuquet J, Lecrux C, Chatenet D, Leprince J, Chazalviel L, Roussel S, MacKenzie
ET, Vaudry H, and Touzani O (2008) Effects of urotensin-II on cerebral blood flow
and ischemia in anesthetized rats. Exp Neurol 210:577–584.
Clark SD, Nothacker HP, Blaha CD, Tyler CJ, Duangdao DM, Grupke SL, Helton
DR, Leonard CS, and Civelli O (2005) Urotensin II acts as a modulator of meso-
pontine cholinergic neurons. Brain Res 1059:139–148.
Clark SD, Nothacker HP, Wang Z, Saito Y, Leslie FM, and Civelli O (2001) The
urotensin II receptor is expressed in the cholinergic mesopontine tegmentum of the
rat. Brain Res 923:120–127.
Clozel M, Binkert C, Birker-Robaczewska M, Boukhadra C, Ding SS, Fischli W, Hess P,
Mathys B, Morrison K, Müller C, et al. (2004) Pharmacology of the urotensin-II
receptor antagonist palosuran (ACT-058362; 1- [2-(4-benzyl-4-hydroxy-piperidin-1-yl)-
ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt): first demonstration of a patho-
physiological role of the urotensin System. JPharmacolExpTher311:204–212.
Clozel M, Hess P, Qiu C, Ding SS, and Rey M (2006) The urotensin-II receptor
antagonist palosuran improves pancreatic and renal function in diabetic rats.
JPharmacol Exp Ther 316:1115–1121.
Conlon JM (2000) Singular contributions of fish neuroendocrinology to mammalian
regulatory peptide research. Regul Pept 93:3–12.
Conlon JM (2008) Liberation of urotensin II from the teleost urophysis: an historical
overview. Peptides 29:651–657.
Conlon JM, Arnold-Reed D, and Balment RJ (1990) Post-translational processing of
prepro-urotensin II. FEBS Lett 266:37–40.
Conlon JM, Kolodziejek J, and Nowotny N (2009) Antimicrobial peptides from the
skins of North American frogs. Biochim Biophys Acta 1788:1556–1563.
252 Vaudry et al.
Conlon JM, O’Harte F, Smith DD, Balment RJ, and Hazon N (1992a) Purification
and characterization of urotensin II and parvalbumin from an elasmobranch fish,
Scyliorhinus canicula (common dogfish). Neuroendocrinology 55:230–235.
Conlon JM, O’Harte F, Smith DD, Tonon MC, and Vaudry H (1992b) Isolation and
primary structure of urotensin II from the brain of a tetrapod, the frog Rana
ridibunda. Biochem Biophys Res Commun 188:578–583.
Conlon JM, Tostivint H, and Vaudry H (1997) Somatostatin- and urotensin II-related
peptides: molecular diversity and evolutionary perspectives. Regul Pept 69:95–103.
Conlon JM, Yano K, Waugh D, and Hazon N (1996) Distribution and molecular forms
of urotensin II and its role in cardiovascular regulation in vertebrates. J Exp Zool
275:226–238.
Cosenzi A (2008) Non peptidic urotensin II antagonists: perspectives for a new class
of drugs. Cardiovasc Hematol Agents Med Chem 6:80–91.
Coulouarn Y, Fernex C, Jégou S, Henderson CE, Vaudry H, and Lihrmann I (2001)
Specific expression of the urotensin II gene in sacral motoneurons of developing rat
spinal cord. Mech Dev 101:187–190.
Coulouarn Y, Jégou S, Tostivint H, Vaudry H, and Lihrmann I (1999) Cloning, se-
quence analysis and tissue distribution of the mouse and rat urotensin II pre-
cursors. FEBS Lett 457:28–32.
Coulouarn Y, Lihrmann I, Jegou S, Anouar Y, Tostivint H, Beauvillain JC, Conlon
JM, Bern HA, and Vaudry H (1998) Cloning of the cDNA encoding the urotensin II
precursor in frog and human reveals intense expression of the urotensin II gene in
motoneurons of the spinal cord. Proc Natl Acad Sci USA 95:15803–15808.
Cowley E, Thompson JP, Sharpe P, Waugh J, Ali N, and Lambert DG (2005) Effects
of pre-eclampsia on maternal plasma, cerebrospinal fluid, and umbilical cord
urotensin II concentrations: a pilot study. Br J Anaesth 95:495–499.
Coy DH, Rossowski WJ, Cheng BL, Hocart SJ, and Taylor JE (2000) Novel urotensin II
(UII) antagonists point to multiple receptor involvement in UII bioactivity. 13th Inter-
nationl Symposium on Regulatory Peptides;2000Oct22–26; Cairns, QLD, Australia.
Coy DH, Rossowski WJ, Cheng BL, and Taylor JE (2002) Structural requirements at
the N-terminus of urotensin II octapeptides. Peptides 23:2259–2264.
Croston GE, Olsson R, Currier EA, Burstein ES, Weiner D, Nash N, Severance D,
Allenmark SG, Thunberg L, Ma JN , et al. (2002) Discovery of the first nonpeptide
agonist of the GPR14/urotensin-II receptor: 3-(4-chlorophenyl)-3-(2- (dimethylamino)
ethyl)isochroman-1-one (AC-7954). J Med Chem 45:4950–4953.
Dahlgren U (1914) The electric motor nerve centers in the skates (RAJIDAe). Science
40:862–863.
Dai HY, He T, Li XL, Xu WL, and Ge ZM (2011) Urotensin-2 promotes collagen
synthesis via ERK1/2-dependent and ERK1/2-independent TGF-b1in neonatal
cardiac fibroblasts. Cell Biol Int 35:93–98.
Dai HY, Kang WQ, Wang X, Yu XJ, Li ZH, Tang MX, Xu DL, Li CW, Zhang Y, and Ge
ZM (2007) The involvement of transforming growth factor-beta1 secretion in uro-
tensin II-induced collagen synthesis in neonatal cardiac fibroblasts. Regul Pept
140:88–93.
Davenport AP and Maguire JJ (2000) Urotensin II: fish neuropeptide catches orphan
receptor. Trends Pharmacol Sci 21:80–82.
Decatur WA, Hall JA, Smith JJ, Li W, and Sower SA (2013) Insight from the lamprey
genome: glimpsing early vertebrate development via neuroendocrine-associated
genes and shared synteny of gonadotropin-releasing hormone (GnRH). Gen Comp
Endocrinol 192:237–245.
de Lecea L and Bourgin P (2008) Neuropeptide interactions and REM sleep: a role for
Urotensin II? Peptides 29:845–851.
de Lecea L, Criado JR, Prospero-Garcia O, Gautvik KM, Schweitzer P, Danielson PE,
Dunlop CL, Siggins GR, Henriksen SJ, and Sutcliffe JG (1996) A cortical neuropep-
tide with neuronal depressant and sleep-modulating properties. Nature 381:242–245.
Delmeire D, Flamez D, Hinke SA, Cali JJ, Pipeleers D, and Schuit F (2003) Type VIII
adenylyl cyclase in rat beta cells: coincidence signal detector/generator for glucose
and GLP-1. Diabetologia 46:1383–1393.
d’Emmanuele di Villa Bianca R, Cirino G, Mitidieri E, Coletta C, Grassia G, Roviezzo
F, Grieco P, Novellino E, Imbimbo C, Mirone V, et al. (2010) Urotensin II: a novel
target in human corpus cavernosum. J Sex Med 7:1778–1786.
Desai N, Sajjad J, and Frishman WH (2008) Urotensin II: a new pharmacologic
target in the treatment of cardiovascular disease. Cardiol Rev 16:142–153.
Desrues L, Lefebvre T, Lecointre C, Schouft MT, Leprince J, Compère V, Morin F,
Proust F, Gandolfo P, Tonon MC, et al. (2012) Down-regulation of GABA(A) re-
ceptor via promiscuity with the vasoactive peptide urotensin II receptor. Potential
involvement in astrocyte plasticity. PLoS ONE 7:e36319.
Dhanak D, Gallagher TF, and Knight SD (2002) inventors, Smithkline Beecham
Corp., USA, assignee. Preparation of sulfonamides as antagonists of urotensin II.
Patent WO 2002-090353. 2002 Nov 14.
Dhanak D and Knight SD (2002) inventors, Smithkline Beecham Corp., USA, as-
signee. Preparation of quinolones as urotensin-II receptor antagonists. Patent WO
2002-047456. 2002 Jun 20.
Dhanak D, Knight SD, Warren GL, Jin J, Widdowson KL, and Keenan RM (2001)
inventors, Smithkline Beecham Corp., USA, assignee. Pyrrolidine derivative uro-
tensin II receptor antagonists, their preparation, and therapeutic use. Patent WO
2001045700. 2001 Jun 28.
Diallo M, Jarry M, Desrues L, Castel H, Chatenet D, Leprince J, Vaudry H, Tonon
MC, and Gandolfo P (2008) [Orn5]URP acts as a pure antagonist of urotensinergic
receptors in rat cortical astrocytes. Peptides 29:813–819.
Disa J, Floyd LE, Edwards RM, Do uglas SA, and Aiyar NV (2006) Identification
and characterization o f binding sites for human urotensin- II in Sprague-Dawley
rat renal medulla using quantitative receptor autoradiography. Peptides 27:
1532–1537.
Djordjevic T, BelAiba RS, Bonello S, Pfeilschifter J, Hess J, and Görlach A (2005)
Human urotensin II is a novel activator of NADPH oxidase in human pulmonary
artery smooth muscle cells. Arterioscler Thromb Vasc Biol 25:519–525.
Doan ND, Nguyen TT, Létourneau M, Turcotte K, Fournier A, and Chatenet D (2012)
Biochemical and pharmacological characterization of nuclear urotensin-II binding
sites in rat heart. Br J Pharmacol 166:243–257.
do Rego JC, Leprince J, Scalbert E, Vaudry H, and Costentin J (2008) Behavioral
actions of urotensin-II. Peptides 29:838–844.
do Rego JC, Chatenet D, Orta MH, Naudin B, Le Cudennec C, Leprince J, Scalbert E,
Vaudry H, and Costentin J (2005) Behavioral effects of urotensin-II centrally ad-
ministered in mice. Psychopharmacology (Berl) 183:103–117.
Douglas SA, Ashton DJ, Sauermelch CF, Coatney RW, Ohlstein DH, Ruffolo MR,
Ohlstein EH, Aiyar NV, and Willette RN (2000a) Human urotensin-II is a potent
vasoactive peptide: pharmacological characterization in the rat, mouse, dog and
primate. J Cardiovasc Pharmacol 36(5, Suppl 1)S163–S166.
Douglas SA, Behm DJ, Aiyar NV, Naselsky D, Disa J, Brooks DP, Ohlstein EH,
Gleason JG, Sarau HM, Foley JJ, et al. (2005) Nonpeptidic urotensin-II receptor
antagonists I: in vitro pharmacological characterization of SB-706375. Br J
Pharmacol 145:620–635.
Douglas SA, Dhanak D, and Johns DG (2004a) From ‘gills to pills’: urotensin-II as
a regulator of mammalian cardiorenal function. Trends Pharmacol Sci 25:76–85.
Douglas SA, Naselsky D, Ao Z, Disa J, Herold CL, Lynch F, and Aiyar NV (2004b)
Identification and pharmacological characterization of native, functional human
urotensin-II receptors in rhabdomyosarcoma cell lines. Br J Pharmacol 142:
921–932.
Douglas SA and Ohlstein EH (2000) Human urotensin-II, the most potent mam-
malian vasoconstrictor identified to date, as a therapeutic target for the manage-
ment of cardiovascular disease. Trends Cardiovasc Med 10:229–237.
Douglas SA, Sulpizio AC, Piercy V, Sarau HM, Ames RS, Aiyar NV, Ohlstein EH,
and Willette RN (2000b) Differential vasoconstrictor activity of human urotensin-II
in vascular tissue isolated from the rat, mouse, dog, pig, marmoset and cynomolgus
monkey. Br J Pharmacol 131:1262–1274.
Douglas SA, Tayara L, Ohlstein EH, Halawa N, and Giaid A (2002) Congestive heart
failure and expression of myocardial urotensin II. Lancet 359:1990–1997.
Dschietzig T, Bartsch C, Pregla R, Zurbrügg HR, Armbruster FP, Richter C, Laule M,
Romeyke E, Neubert C, Voelter W, et al. (2002) Plasma levels and cardiovascular
gene expression of urotensin-II in human heart failure. Regul Pept 110:33–38.
Du AT, Onan D, Dinh DT, Lew MJ, Ziogas J, Aguilar MI, Pattenden LK, Thomas WG
(2010) Ligand-supported purification of the urotensin-II receptor. Mol Pharmacol
78:639–647.
Dubessy C, Cartier D, Lectez B, Bucharles C, Chartrel N, Montero-Hadjadje M, Bizet
P, Chatenet D, Tostivint H, Scalbert E, et al. (2008) Characterization of urotensin
II, distribution of urotensin II, urotensin II-related peptide and UT receptor
mRNAs in mouse: evidence of urotensin II at the neuromuscular junction.
J Neurochem 107:361–374.
Dun SL, Brailoiu GC, Yang J, Chang JK, and Dun NJ (2001) Urotensin II-immunoreactivity
in the brainstem and spinal cord of the rat. Neurosci Lett 305:9–12.
Egginger JG, Camus A, and Calas A (2006) Urotensin-II expression in the mouse
spinal cord. J Chem Neuroanat 31:146–154.
Elshourbagy NA, Douglas SA, Shabon U, Harrison S, Duddy G, Sechler JL, Ao Z,
Maleeff BE, Naselsky D, Disa J, et al. (2002) Molecular and pharmacological
character ization of genes encoding urote nsin-II pep tides and the ir cognate
G-protein-coupled receptors from the mouse and monkey. Br J Pharmacol 136:9–22.
Enami M (1959) The morphology and functional significance of the caudal neurose-
cretory system of fishes, in Comparative Endocrinology (Gorbman A ed) pp 697–724,
Wiley, New York.
Evans DH, Hyndman KA, Cornwell E, and Buchanan P (2011) Urotensin II and its
receptor in the killifish gill: regulators of NaCl extrusion. J Exp Biol 214:
3985–3991.
Feuilloley M, Lesouhaitier O, Delarue C, De Marchis S, Conlon JM, Bern HA,
and Vaudry H (1994) In vitro study of the effect of urotensin II on corticosteroid
secretion in the frog Rana ridibunda. J Steroid Biochem Mol Biol 48:287–292.
Filipeanu CM, Brailoiu E, Le Dun S, and Dun NJ (2002) Urotensin-II regulates
intracellular calcium in dissociated rat spinal cord neurons. J Neurochem 83:
879–884.
Flohr S, Kurz M, Kostenis E, Brkovich A, Fournier A, and Klabunde T (2002)
Identification of nonpeptidic urotensin II receptor antagonists by virtual screening
based on a pharmacophore model derived from structure-activity relationships and
nuclear magnetic resonance studies on urotensin II. J Med Chem 45:1799–1805.
Foister S, Taylor LL, Feng JJ, Chen WL, Lin A, Cheng FC, Smith AB 3rd,
and Hirschmann R (2006) Design and synthesis of potent cystine-free cyclic hex-
apeptide agonists at the human urotensin receptor. Org Lett 8:1799–1802.
Forty EJ and Ashton N (2013) The urotensin system is up-regulated in the pre-
hypertensive spontaneously hypertensive rat. PLoS ONE 8:e83317.
Fredriksson R and Schiöth HB (2005) The repertoire of G-protein-coupled receptors
in fully sequenced genomes. Mol Pharmacol 67:1414–1425.
Fridberg G and Bern HA (1968) The urophysis and the caudal neurosecretory system
of fishes. Biol Rev Camb Philos Soc 43:175–199.
Gardiner SM, March JE, Kemp PA, Davenport AP, and Bennett T (2001) Depressor
and regionally-selective vasodilator effects of human and rat urotensin II in con-
scious rats. Br J Pharmacol 132:1625–1629.
Gartlon J, Parker F, Harrison DC, Douglas SA, Ashmeade TE, Riley GJ, Hughes ZA,
Taylor SG, Munton RP, Hagan JJ, et al. (2001) Central effects of urotensin-II
following ICV administration in rats. Psychopharmacology (Berl) 155:426–433.
Gibson A (1987) Complex effects of Gillichthys urotensin II on rat aortic strips. Br J
Pharmacol 91:205–212.
Gibson A, Bern HA, Ginsburg M, and Botting JH (1984) Neuropeptide-induced
contraction and relaxation of the mouse anococcygeus muscle. Proc Natl Acad Sci
USA 81:625–629.
Gibson A, Conyers S, and Bern HA (1988) The influence of urotensin II on calcium
flux in rat aorta. J Pharm Pharmacol 40:893–895.
Gibson A, Wallace P, and Bern HA (1986) Cardiovascular effects of urotensin II in
anesthetized and pithed rats. Gen Comp Endocrinol 64:435–439.
Gilbert RE, Douglas SA, and Krum H (2004) Urotensin-II as a novel therapeutic
target in the clinical management of cardiorenal disease. Curr Opin Investig Drugs
5:276–282.
Urotensin II and Its Receptor 253
Gilon P and Henquin JC (2001) Mechanisms and physiological significance of the
cholinergic control of pancreatic beta-cell function. Endocr Rev 22:565–604.
Giuliani L, Lenzini L, Antonello M, Aldighieri E, Belloni AS, Fassina A, Gomez-
Sanchez C, and Rossi GP (2009) Expression and functional role of urotensin-II and
its receptor in the adrenal cortex and medulla: novel insights for the pathophysi-
ology of primary aldosteronism. J Clin Endocrinol Metab 94:684–690.
Gong H, Ma H, Liu M, Zhou B, Zhang G, Chen Z, Jiang G, Yan Y, Yang C, Kanda M,
et al. (2011) Urotensin II inhibits the proliferation but not the differentiation of
cardiac side population cells. Peptides 32:1035–1041.
Gong H, Wang YX, Zhu YZ, Wang WW, Wang MJ, Yao T, and Zhu YC (2004) Cellular
distribution of GPR14 and the positive inotropic role of urotensin II in the myo-
cardium in adult rat. J Appl Physiol 97:2228–2235.
González GC, Martinez-Padrón M, Lederis K, and Lukowiak K (1992) Distribution
and coexistence of urotensin I and urotensin II peptides in the cerebral ganglia of
Aplysia californica. Peptides 13:695–703.
Grau EG, Nishioka RS, and Bern HA (1982) Effects of somatostatin and urotensin II
on tilapia pituitary prolactin release and interactions between somatostatin, os-
motic pressure Ca++, and adenosine 39,59-monophosphate in prolactin release in
vitro. Endocrinology 110:910–915.
Gray GA, Jones MR, and Sharif I (2001) Human urotensin II increases coronary
perfusion pressure in the isolated rat heart: potentiation by nitric oxide synthase
and cyclooxygenase inhibition. Life Sci 69:175–180.
Grieco P, Carotenuto A, Campiglia P, Gomez-Monterrey I, Auriemma L, Sala M,
Marcozzi C, d’Emmanuele di Villa Bianca R, Brancaccio D, Rovero P, et al. (2009)
New insight into the binding mode of peptide ligands at Urotensin-II receptor:
structure-activity relationships study on P5U and urantide. J Med Chem 52:
3927–3940.
Grieco P, Carotenuto A, Campiglia P, Marinelli L, Lama T, Patacchini R, Santicioli P,
Maggi CA, Rovero P, and Novellino E (2005) Urotensin-II receptor ligands. From
agonist to antagonist activity. J Med Chem 48:7290–7297.
Grieco P, Carotenuto A, Campiglia P, Zampelli E, Patacchini R, Maggi CA, Novellino
E, and Rovero P (2002a) A new, potent urotensin II receptor peptide agonist con-
taining a Pen residue at the disulfide bridge. J Med Chem 45:4391–4394.
Grieco P, Carotenuto A, Patacchini R, Maggi CA, Novellino E, and Rovero P (2002b)
Design, synthesis, conformational analysis, and biological studies of urotensin-II
lactam analogues. Bioorg Med Chem 10:3731–3739.
Grieco P, Franco R, Bozzuto G, Toccacieli L, Sgambato A, Marra M, Zappavigna S,
Migaldi M, Rossi G, Striano S, et al. (2011) Urotensin II receptor predicts the
clinical outcome of prostate cancer patients and is involved in the regulation of
motility of prostate adenocarcinoma cells. J Cell Biochem 112:341–353.
Gruson D, Ginion A, Decroly N, Lause P, Vanoverschelde JL, Ketelslegers JM,
Bertrand L, and Thissen JP (2010a) Urotensin II induction of adult cardiomyocytes
hypertrophy involves the Akt/GSK-3bsignaling pathway. Peptides 31:1326–1333.
Gruson D, Rousseau MF, Ahn SA, van Linden F, and Ketelslegers JM (2006) Cir-
culating urotensin II levels in moderate to severe congestive heart failure: its
relations with myocardial function and well established neurohormonal markers.
Peptides 27:1527–1531.
Gruson D, Rousseau MF, Ketelslegers JM, and Hermans MP (2010b) Raised plasma
urotensin II in type 2 diabetes patients is associated with the metabolic syndrome
phenotype. J Clin Hypertens (Greenwich) 12:653–660.
Guerrini R, Camarda V, Marzola E, Arduin M, Calo G, Spagnol M, Rizzi A, Salvadori
S, and Regoli D (2005) Structure-activity relationship study on human urotensin II.
J Pept Sci 11:85–90.
Guidolin D, Albertin G, Oselladore B, Sorato E, Rebuffat P, Mascarin A, and Ribatti
D (2010) The pro-angiogenic activity of urotensin-II on human vascular endothelial
cells involves ERK1/2 and PI3K signaling pathways. Regul Pept 162:26–32.
Hassan GS, Douglas SA, Ohlstein EH, and Giaid A (2005) Expression of urotensin-II
in human coronary atherosclerosis. Peptides 26:2464–2472.
Hay DW, Luttmann MA, and Douglas SA (2000) Human urotensin-II is a potent
spasmogen of primate airway smooth muscle. Br J Pharmacol 131:10–12.
Hazon N, Bjenning C, and Conlon JM (1993) Cardiovascular actions of dogfish uro-
tensin II in the dogfish Scyliorhinus canicula. Am J Physiol 265:R573–R576.
Heller J, Schepke M, Neef M, Woitas R, Rabe C, and Sauerbruch T (2002) Increased
urotensin II plasma levels in patients with cirrhosis and portal hypertension.
J Hepatol 37:767–772.
Henquin JC, Debuyser A, Drews G, and Plant TD (1992) Regulation of K+ perme-
ability and membrane potential in insulin-secretin cells, in Nutrient Regulation of
Insulin Secretion (Flatt PR ed) pp 173–191, Portland Press, London.
Heringlake M, Kox T, Uzun O, Will B, Bahlmann L, Klaus S, Eleftheriadis S,
Armbruster FP, Franz N, and Kraatz E (2004) The relationship between urotensin
II plasma immunoreactivity and left ventricular filling pressures in coronary ar-
tery disease. Regul Pept 121:129–136.
Herold CL, Behm DJ, Buckley PT, Foley JJ, Wixted WE, Sarau HM, and Douglas SA
(2003) The neuromedin B receptor antagonist, BIM-23127, is a potent antagonist
at human and rat urotensin-II receptors. Br J Pharmacol 139:203–207.
Hess P, Lansman JB, and Tsien RW (1984) Different modes of Ca channel gating
behaviour favoured by dihydropyridine Ca agonists and antagonists. Nature 311:
538–544.
Hillier C, Berry C, Petrie MC, O’Dwyer PJ, Hamilton C, Brown A, and McMurray J
(2001) Effects of urotensin II in human arteries and veins of varying caliber. Cir-
culation 103:1378–1381.
Hirose T, Takahashi K, Mori N, Nakayama T, Kikuya M, Ohkubo T, Kohzuki M,
Totsune K, and Imai Y (2009) Increased expression of urotensin II, urotensin
II-related peptide and urotensin II receptor mRNAs in the cardiovascular organs of
hypertensive rats: comparison with endothelin-1. Peptides 30:1124–1129.
Holleran BJ, Beaulieu ME, Proulx CD, Lavigne P, Escher E, and Leduc R (2007)
Photolabelling the urotensin II receptor reveals distinct agonist- and partial-
agonist-binding sites. Biochem J 402:51–61.
Holleran BJ, Domazet I, Beaulieu ME, Yan LP, Guillemette G, Lavigne P, Escher E,
and Leduc R (2009) Identification of transmembrane domain 6 & 7 residues that
contribute to the binding pocket of the urotensin II receptor. Biochem Pharmacol
77:1374–1382.
Hood SG, Watson AM, and May CN (2005) Cardiac actions of central but not pe-
ripheral urotensin II are prevented by beta-adrenoceptor blockade. Peptides 26:
1248–1256.
Horie S, Tsurumaki Y, Someya A, Hirabayashi T, Saito T, Okuma Y, Nomura Y,
and Murayama T (2005) Involvement of cyclooxygenase-dependent pathway in
contraction of isolated ileum by urotensin II. Peptides 26:323–329.
Horie S, Yasuda S, Tsurumaki Y, Someya A, Saito T, Okuma Y, Nomura Y,
Hirabayashi T, and Murayama T (2003) Contraction of isolated guinea-pig ileum by
urotensin II via activation of ganglionic cholinergic neurons and acetylcholine release.
Neuropharmacology 45:1019–1027.
Huitron-Resendiz S, Kristensen MP, Sánchez-Alavez M, Clark SD, Grupke SL, Tyler
C, Suzuki C, Nothacker HP, Civelli O, Criado JR, et al. (2005) Urotensin II mod-
ulates rapid eye movement sleep through activation of brainstem cholinergic
neurons. J Neurosci 25:5465–5474.
Hunt BD, Ng LL, and Lambert DG (2010) A rat brain atlas of urotensin-II receptor
expression and a review of central urotensin-II effects. Naunyn Schmiedebergs
Arch Pharmacol 382:1–31.
Ichikawa T, Lederis K, and Kobayashi H (1984) Primary structures of multiple forms
of urotensin II in the urophysis of the carp, Cyprinus carpio. Gen Comp Endocrinol
55:133–141.
Ishihata A, Sakai M, and Katano Y (2006) Vascular contractile effect of urotensin II
in young and aged rats: influence of aging and contribution of endothelial nitric
oxide. Peptides 27:80–86.
Itoh H, Itoh Y, Rivier J, and Lederis K (1987) Contraction of major artery segments of
rat by fish neuropeptide urotensin II. Am J Physiol 252:R361–R366.
Itoh H, McMaster D, and Lederis K (1988) Functional receptors for fish neuropeptide
urotensin II in major rat arteries. Eur J Pharmacol 149:61–66.
Jacobs BL (1985) Overview of the activity of brain monoaminergic neurons across the
sleep-wake cycle, in Sleep: Neurotransmitters and Neuromodulators (Wauquier A,
Monti JM, Gaillard JM, and Radulovacki M eds) pp 1–14, Raven Press, New York.
Jani PP, Narayan H, and Ng LL (2013) The differential extraction and immunolu-
minometric assay of Urotensin II and Urotensin-related peptide in heart failure.
Peptides 40:72–76.
Jarry M, Diallo M, Lecointre C, Desrues L, Tokay T, Chatenet D, Leprince J, Rossi O,
Vaudry H, Tonon MC, et al. (2010) The vasoactive peptides urotensin II and uro-
tensin II-related peptide regulate astrocyte activity through common and distinct
mechanisms: involvement in cell proliferation. Biochem J 428:113–124.
Javitch JA, Shi L, and Liapakis G (2002) Use of the substituted cysteine accessibility
method to study the structure and function of G protein-coupled receptors. Methods
Enzymol 343:137–156.
Jégou S, Cartier D, Dubessy C, Gonzalez BJ, Chatenet D, Tostivint H, Scalbert E,
Leprince J, Vaudry H, and Lihrmann I (2006) Localization of the urotensin II
receptor in the rat central nervous system. J Comp Neurol 495:21–36.
Jiang Z, Michal JJ, Tobey DJ, Wang Z, Macneil MD, and Magnuson NS (2008)
Comparative understanding of UTS2 and UTS2R genes for their involvement in
type 2 diabetes mellitus. Int J Biol Sci 4:96–102.
Jin J, Dhanak D, Knight SD, Widdowson K, Aiyar N, Naselsky D, Sarau HM, Foley JJ,
Schmidt DB, Bennett CD, et al. (2005) Aminoalkoxy benzyl pyrrolidines as novel
human urotensin-II receptor antagonists. Bioorg Med Chem Lett 15:3229–3232.
Johns DG, Ao Z, Naselsky D, Herold CL, Maniscalco K, Sarov-Blat L, Steplewski K,
Aiyar N, and Douglas SA (2004) Urotensin-II-mediated cardiomyocyte hypertro-
phy: effect of receptor antagonism and role of inflammatory mediators. Naunyn
Schmiedebergs Arch Pharmacol 370:238–250.
Jołda-Mydłowska B, Salomon P, and Mazurek W (2006) [Plasma urotensin II level in
patients with chronic congestive heart failure]. Pol Arch Med Wewn 116:
1125–1136.
Katz SD (1997) Mechanisms and implications of endothelial dysfunction in conges-
tive heart failure. Curr Opin Cardiol 12:259–264.
Kawaguchi Y, Ono T, Kudo M, Kushikata T, Hashiba E, Yoshida H, Kudo T, Fur-
ukawa K, Douglas SA, and Hirota K (2009) The effects of benzodiazepines on
urotensin II-stimulated norepinephrine release from rat cerebrocortical slices.
Anesth Analg 108:1177–1181.
Kawauchi H, Kawazoe I, Tsubokawa M, Kishida M, and Baker BI (1983) Charac-
terization of melanin-concentrating hormone in chum salmon pituitaries. Nature
305:321–323.
Kelsall CJ and Balment RJ (1998) Native urotensins influence cortisol secretion and
plasma cortisol concentration in the euryhaline flounder, platichthys flesus. Gen
Comp Endocrinol 112:210–219.
Kemp W, Krum H, Colman J, Bailey M, Yandle T, Richards M, and Roberts S (2007)
Urotensin II: a novel vasoactive mediator linked to chronic liver disease and portal
hypertension. Liver Int 27:1232–1239.
Kessler RJ and Wu C (2009) inventors, Encysive Pharmaceuticals Inc., USA, as-
signee. Quinoline derivatives as urotensin-II receptor antagonists and their prep-
aration, pharmaceutical compositions and use in the treatment of diseases. Patent
WO 2009-053895. 2009 Apr 30.
Khan SQ, Bhandari SS, Quinn P, Davies JE, and Ng LL (2007) Urotensin II is raised
in acute myocardial infarction and low levels predict risk of adverse clinical out-
come in humans. Int J Cardiol 117:323–328.
Kim SK, Li Y, Park C, Abrol R, and Goddard WA 3rd (2010) Prediction of the three-
dimensional structure for the rat urotensin II receptor, and comparison of the
antagonist binding sites and binding selectivity between human and rat receptors
from atomistic simulations. ChemMedChem 5:1594–1608.
Kinney WA, Almond HR Jr, Qi J, Smith CE, Santulli RJ, de Garavilla L, Andrade-
Gordon P, Cho DS, Everson AM, Feinstein MA, et al. (2002) Structure-function
analysis of urotensin II and its use in the construction of a ligand-receptor working
model. Angew Chem Int Ed Engl 41:2940–2944.
Kirchmair R, Hogue-Angeletti R, Gutierrez J, Fischer-Colbrie R, and Winkler H
(1993) Secretoneurin—a neuropeptide generated in brain, adrenal medulla and
254 Vaudry et al.
other endocrine tissues by proteolytic processing of secretogranin II (chromogranin
C). Neuroscience 53:359–365.
Kobayashi Y, Lederis K, Rivier J, Ko D, McMaster D, and Poulin P (1986) Radio-
immunoassays for fish tail neuropeptides: II. Development of a specific and sensitive
assay for and the occurrence of immunoreactive urotensin II in the central nervous
system and blood of Catostomus commersoni. J Pharmacol Methods 15:321–333.
Kompa AR, Thomas WG, See F, Tzanidis A, Hannan RD, and Krum H (2004) Cardio-
vascular role of urotensin II: effect of chronic infusion in the rat. Peptides 25:1783–1788.
Konno N, Fujii Y, Imae H, Kaiya H, Mukuda T, Miyazato M, Matsuda K,
and Uchiyama M (2013) Urotensin II receptor (UTR) exists in hyaline chon-
drocytes: a study of peripheral distribution of UTR in the African clawed frog,
Xenopus laevis. Gen Comp Endocrinol 185:44–56.
Kriegsfeld LJ, Mei DF, BentleyGE, UbukaT, Mason AO, Inoue K, Ukena K, Tsutsui K,
and Silver R (2006) Identification and characterization of a gonadotropin-inhibitory
system in the brains of mammals. Proc Natl Acad Sci USA 103:2410–2415.
Kristof AS, You Z, Han YS, and Giaid A (2010) Protein expression of urotensin II,
urotensin-related peptide and their receptor in the lungs of patients with
lymphangioleiomyomatosis. Peptides 31:1511–1516.
Krum H and Gilbert RE (2003) Urotensin II: a new player in vascular and myocardial
disease? Clin Sci (Lond) 104:65–67.
Krum H and Kemp W (2007) Therapeutic potential of blockade of the urotensin II
system in systemic hypertension. Curr Hypertens Rep 9:53–58.
Labarrère P, Chatenet D, Leprince J, Marionneau C, Loirand G, Tonon MC, Dubessy
C, Scalbert E, Pfeiffer B, Renard P, et al. (2003) Structure-activity relationships of
human urotensin II and related analogues on rat aortic ring contraction. J Enzyme
Inhib Med Chem 18:77–88.
Lancien F, Leprince J, Mimassi N, Mabin D, Vaudry H, and Le Mével JC (2004)
Central effects of native urotensin II on motor activity, ventilatory movements, and
heart rate in the trout Oncorhynchus mykiss. Brain Res 1023:167–174.
Langham RG, Kelly DJ, Gow RM, Zhang Y, Dowling JK, Thomson NM, and Gilbert
RE (2004) Increased expression of urotensin II and urotensin II receptor in human
diabetic nephropathy. Am J Kidney Dis 44:826–831.
Lapp H, Boerrigter G, Costello-Boerrigter LC, Jaekel K, Scheffold T, Krakau I,
Schramm M, Guelker H, and Stasch JP (2004) Elevated plasma human urotensin-
II-like immunoreactivity in ischemic cardiomyopathy. Int J Cardiol 94:93–97.
Larhammar D, Bergqvist C, Sundström G, and Ocampo Daza D (2012) Evolution of
receptors for somatostatin and urotensin II. 26th Conference of European Com-
parative Endocrinologists; 2012 Aug 21–25; Zurich, Switzerland. pp A13.5.
Lavecchia A, Cosconati S, and Novellino E (2005) Architecture of the human uro-
tensin II receptor: comparison of the binding domains of peptide and non-peptide
urotensin II agonists. J Med Chem 48:2480–2492.
Lawson EC, Luci DK, Ghosh S, Kinney WA, Reynolds CH, Qi J, Smith CE, Wang Y,
Minor LK, Haertlein BJ, et al. (2009) Nonpeptide urotensin-II receptor antagonists:
a new ligand class based on piperazino-phthalimide and piperazino-isoindolinone
subunits. J Med Chem 52:7432–7445.
Lederis K (1970) Teleost urophysis. II. Biological characterization of the bladder-
contracting activity. Gen Comp Endocrinol 14:427–437.
Lederis K, Letter A, McMaster D, Moore G, and Schlesinger D (1982) Complete
amino acid sequence of urotensin I, a hypotensive and corticotropin-releasing
neuropeptide from Catostomus. Science 218:162–165.
LehmannF,CurrierEA,ClemonsB,HansenLK,OlssonR,HacksellU,andLuthmanK
(2009) Novel and potent small-molecule urotensin II receptor agonists. Bioorg Med
Chem 17:4657–4665.
Lehmann F, Currier EA, Olsson R, Hacksell U, and Luthman K (2005) Isochromanone-
based urotensin-II receptor agonists. Bioorg Med Chem 13:3057–3068.
Lehmann F, Pettersen A, Currier EA, Sherbukhin V, Olsson R, Hacksell U,
and Luthman K (2006) Novel potent and efficacious nonpeptidic urotensin II re-
ceptor agonists. J Med Chem 49:2232–2240.
Lehner U, Veli
c A, Schroter R, Schlatter E, and Sindi
c A (2007) Ligands and sig-
naling of the G-protein-coupled receptor GPR14, expressed in human kidney cells.
Cell Physiol Biochem 20:181–192.
Le Mével JC, Lancien F, Mimassi N, and Conlon JM (2012) Brain neuropeptides in
central ventilatory and cardiovascular regulation in trout. Front Endocrinol
(Lausanne) 3:124 10.3389/fendo.2012.00124.
Le Mével JC, Lancien F, Mimassi N, Leprince J, Conlon JM, and Vaudry H (2008)
Central and peripheral cardiovascular, ventilatory, and motor effects of trout
urotensin-II in the trout. Peptides 29:830–837.
Le Mével JC, Leprince J, Lancien F, Mimassi N, and Vaudry H (2013) Cardio-
ventilatory and locomotor effects of centrally administered urotensin II and uro-
tensin II-related peptides in the unanesthetized trout. 17th International Congress
of Comparative Endocrinology; 2013 Jul 15–19; Barcelona. Abst P-131.
Le Mével JC, Olson KR, Conklin D, Waugh D, Smith DD, Vaudry H, and Conlon JM
(1996) Cardiovascular actions of trout urotensin II in the conscious trout, Oncorhynchus
mykiss. Am J Physiol 271:R1335–R1343.
Leprince J, Chatenet D, Dubessy C, Fournier A, Pfeiffer B, Scalbert E, Renard P,
Pacaud P, Oulyadi H, Ségalas-Milazzo I, et al. (2008) Structure-activity relation-
ships of urotensin II and URP. Peptides 29:658–673.
Lescot E, Bureau R, and Rault S (2008a) Nonpeptide Urotensin-II receptor agonists
and antagonists: review and structure-activity relationships. Peptides 29:680–690.
Lescot E, Sopkova-de Oliveira Santos J, Colloc’h N, Rodrigo J, Milazzo-Segalas I, Bu-
reau R, and Rault S (2008b) Three-dimensional model of the human urotensin-II
receptor: docking of human urotensin-II and nonpeptide antagonists in the binding
site and comparison with an antagonist pharmacophore model. Proteins 73:173–184.
Lescot E, Sopkova-de Oliveira Santos J, Dubessy C, Oulyadi H, Lesnard A, Vaudry H,
Bureau R, and Rault S (2007) Definition of new pharmacophores for nonpeptide
antagonists of human urotensin-II. Comparison with the 3D-structure of human
urotensin-II and URP. J Chem Inf Model 47:602–612.
Lihrmann I, Tostivint H, Bern H, and Vaudry H (2013) Urotensin II peptides, in
Handbook of Biologically Active Peptides, 2nd ed (Kastin ED ed), pp 957–965,
Academic Press, New York.
Lim M, Honisett S, Sparkes CD, Komesaroff P, Kompa A, and Krum H (2004) Dif-
ferential effect of urotensin II on vascular tone in normal subjects and patients
with chronic heart failure. Circulation 109:1212–1214.
Lin Y, Tsuchihashi T, Matsumura K, Abe I, and Iida M (2003a) Central cardiovas-
cular action of urotensin II in conscious rats. J Hypertens 21:159–165.
Lin Y, Tsuchihashi T, Matsumura K, Fukuhara M, Ohya Y, Fujii K, and Iida M
(2003b) Central cardiovascular action of urotensin II in spontaneously hyperten-
sive rats. Hypertens Res 26:839–845.
Liu D, Chen J, Wang J, Zhang Z, Ma X, Jia J, and Wang Y (2010a) Increased ex-
pression of urotensin II and GPR14 in patients with cirrhosis and portal hyper-
tension. Int J Mol Med 25:845–851.
Liu F and Zhu YC (2010) Urotensin II inhibits glucokinase expression and glucose-
induced insulin secretion. Sheng Li Xue Bao 62:129–136.
Liu JC, Chen CH, Chen JJ, and Cheng TH (2009) Urotensin II induces rat car-
diomyocyte hypertrophy via the transient oxidization of Src homology 2-containing
tyrosine phosphatase and transactivation of epidermal growth factor receptor. Mol
Pharmacol 76:1186–1195.
Liu Q, Pong SS, Zeng Z, Zhang Q, Howard AD, Williams DL Jr, Davidoff M, Wang R,
Austin CP, McDonald TP, et al. (1999) Identification of urotensin II as the en-
dogenous ligand for the orphan G-protein-coupled receptor GPR14. Biochem Bio-
phys Res Commun 266:174–178.
Liu Y, Lu D, Zhang Y, Li S, Liu X, and Lin H (2010b) The evolution of somatostatin in
vertebrates. Gene 463:21–28.
Loirand G, Rolli-Derkinderen M, and Pacaud P (2008) Urotensin II and atheroscle-
rosis. Peptides 29:778–782.
Loretz CA (1990) Recognition by goby intestine of a somatostatin analog, SMS
201-995. J Exp Zool Suppl 4:31–36.
Loretz CA and Assad JA (1986) Urotensin II lowers cytoplasmic free calcium con-
centration in goby enterocytes: measurements using quin2. Gen Comp Endocrinol
64:355–361.
Loretz CA and Bern HA (1981) Stimulation of sodium transport across the teleost
urinary bladder by urotensin II. Gen Comp Endocrinol 43:325–330.
Loretz C, Bern HA, Foskett JK, and Mainoya JR (1982) The caudal neurosecretory
system and osmoregulation in fish, in Neurosecretion: Molecules, Cells, Systems
(Farner DS and Ledens K eds), pp 319–328, Plenum Press, New York.
Loretz CA, Freel RW, and Bern HA (1983) Specificity of response of intestinal ion
transport systems to a pair of natural peptide hormone analogs: somatostatin and
urotensin II. Gen Comp Endocrinol 52:198–206.
Loretz CA, Howard ME, and Siegel AJ (1985) Ion transport in goby intestine: cellular
mechanism of urotensin II stimulation. Am J Physiol 249:G284–G293.
Lu W, Abdel-Razik AE, Ashton N, and Balment RJ (2008) Urotensin II: lessons from
comparative studies for general endocrinology. Gen Comp Endocrinol 157:14–20.
Lu W, Greenwood M, Dow L, Yuill J, Worthington J, Brierley MJ, McCrohan CR,
Riccardi D, and Balment RJ (2006) Molecular characterization and expression of
urotensin II and its receptor in the flounder (Platichthys flesus): a hormone system
supporting body fluid homeostasis in euryhaline fish. Endocrinology 147:3692–3708.
Lu Y, Zou CJ, Huang DW, and Tang CS (2002) Cardiovascular effects of urotensin II
in different brain areas. Peptides 23:1631–1635.
MacLean MR, Alexander D, Stirrat A, Gallagher M, Douglas SA, Ohlstein EH,
Morecroft I, and Polland K (2000) Contractile responses to human urotensin-II in
rat and human pulmonary arteries: effect of endothelial factors and chronic hyp-
oxia in the rat. Br J Pharmacol 130:201–204.
Maguire JJ, Kuc RE, and Davenport AP (2000) Orphan-receptor ligand human
urotensin II: receptor localization in human tissues and comparison of vasocon-
strictor responses with endothelin-1. Br J Pharmacol 131:441–446.
Maguire JJ, Kuc RE, Kleinz MJ, and Davenport AP (2008) Immunocytochemical
localization of the urotensin-II receptor, UT, to rat and human tissues: relevance to
function. Peptides 29:735–742.
Maguire JJ, Kuc RE, Wiley KE, Kleinz MJ, and Davenport AP (2004) Cellular dis-
tribution of immunoreactive urotensin-II in human tissues with evidence of in-
creased expression in atherosclerosis and a greater constrictor response of small
compared to large coronary arteries. Peptides 25:1767–1774.
Mainoya JR and Bern HA (1982) Effects of teleost urotensins on intestinal absorption
of water and Nacl in tilapia, sarotherodon mossambicus, adapted to fresh water or
seawater. Gen Comp Endocrinol 47:54–58.
Mainoya JR and Bern HA (1984) Influence of vasoactive intestinal peptide and
urotensin II on the absorption of water and NaCl by the anterior intestine of the
tilapia, Sarotherodon mossambicus. Zool Sci 1:100–105.
Malagon MM, Molina M, Gahete MD, Duran-Prado M, Martinez-Fuentes AJ, Alcain
FJ, Tonon MC, Leprince J, Vaudry H, Castaño JP, et al. (2008) Urotensin II and
urotensin II-related peptide activate somatostatin receptor subtypes 2 and 5.
Peptides 29:711–720.
Marchese A, Heiber M, Nguyen T, Heng HH, Saldivia VR, Cheng R, Murphy PM,
Tsui LC, Shi X, Gregor P, et al. (1995) Cloning and chromosomal mapping of three
novel genes, GPR9, GPR10, and GPR14, encoding receptors related to interleukin
8, neuropeptide Y, and somatostatin receptors. Genomics 29:335–344.
Marco J, Egido EM, Hernández R, and Silvestre RA (2008) Evidence for endogenous
urotensin-II as an inhibitor of insulin secretion. Study in the perfused rat pancreas.
Peptides 29:852–858.
Marshall WS and Bern HA (1979) Teleostean urophysis: urotensin II and ion
transport across the isolated skin of a marine teleost. Science 204:519–521.
Marshall WS and Bern HA (1981) Active chloride transport by the skin of a marine
teleost is stimulated by urotensin I and inhibited by urotensin II. Gen Comp
Endocrinol 43:484–491.
Maryanoff BE and Kinney WA (2010) Urotensin-II receptor modulators as potential
drugs. J Med Chem 53:2695–2708.
Matsumoto Y, Abe M, Watanabe T, Adachi Y, Yano T, Takahashi H, Sugo T, Mori M,
Kitada C, Kurokawa T, et al. (2004) Intracerebroventricular administration of
urotensin II promotes anxiogenic-like behaviors in rodents. Neurosci Lett 358:
99–102.
Urotensin II and Its Receptor 255
Matsushita M, Shichiri M, Fukai N, Ozawa N, Yoshimoto T, Takasu N, and Hirata Y
(2003) Urotensin II is an autocrine/paracrine growth factor for the porcine renal
epithelial cell line, LLCPK1. Endocrinology 144:1825–1831.
Matsushita M, Shichiri M, Imai T, Iwashina M, Tanaka H, Takasu N, and Hirata Y
(2001) Co-expression of urotensin II and its receptor (GPR14) in human cardio-
vascular and renal tissues. J Hypertens 19:2185–2190.
McCrohan CR, Lu W, Brierley MJ, Dow L, and Balment RJ (2007) Fish caudal
neurosecretory system: a model for the study of neuroendocrine secretion. Gen
Comp Endocrinol 153:243–250.
McDonald J, Batuwangala M, and Lambert DG (2007) Role of urotensin II and its
receptor in health and disease. J Anesth 21:378–389.
McMaster D, Belenky MA, Polenov AL, and Lederis K (1992) Isolation and amino
acid sequence of urotensin II from the sturgeon Acipenser ruthenus. Gen Comp
Endocrinol 87:275–285.
McMaster D, Kobayashi Y, Rivier J, and Lederis K (1986) Characterization of the
biologically and antigenically important regions of urotensin II. Proc West Phar-
macol Soc 29:205–208.
McMaster D and Lederis K (1983) Isolation and amino acid sequence of two urotensin
II peptides from Catostomus commersoni urophyses. Peptides 4:367–373.
Medakovic M, Chan DK, and Lederis K (1975) Pharmacological effects of urotensins.
I. Regional vascular effects of urotensins I and II in the rat. Pharmacology 13:
409–418.
Merlino F, Di Maro S, Munaim Yousif A, Caraglia M, and Grieco P (2013) Urotensin-II
ligands: An overview from peptide to nonpeptide structures. J Amino Acids DOI:
10.1155/2013/979016.
Mirabeau O and Joly JS (2013) Molecular evolution of peptidergic signaling systems
in bilaterians. Proc Natl Acad Sci USA 110:E2028–E2037.
Mori M, Sugo T, Abe M, Shimomura Y, Kurihara M, Kitada C, Kikuchi K, Shintani Y,
Kurokawa T, Onda H, et al. (1999) Urotensin II is the endogenous ligand of a
G-protein-coupled orphan receptor, SENR (GPR14). Biochem Biophys Res Commun
265:123–129.
Mori N, Hirose T, Nakayama T, Ito O, Kanazawa M, Imai Y, Kohzuki M, Takahashi
K, and Totsune K (2009) Increased expression of urotensin II-related peptide and
its receptor in kidney with hypertension or renal failure. Peptides 30:400–408.
Morimoto R, Satoh F, Murakami O, Totsune K, Arai Y, Suzuki T, Sasano H, Ito S,
and Takahashi K (2008) Immunolocalization of urotensin II and its receptor in
human adrenal tumors and attached non-neoplastic adrenal tissues. Peptides 29:
873–880.
Muramatsu I and Kobayashi Y (1979) Effects of urotensins on the cardiovascular
system of a teleost fish and a bird. 16th Gunma Symposia on Endocrinology; 1978
May 31–Jun 1; Maebashi, Japan. pp 49–56.
Nakayama T, Hirose T, Totsune K, Mori N, Maruyama Y, Maejima T, Minagawa K,
Morimoto R, Asayama K, Kikuya M, et al. (2008) Increased gene expression of
urotensin II-related peptide in the hearts of rats with congestive heart failure.
Peptides 29:801–808.
Ng LL, Loke I, O’Brien RJ, Squire IB, and Davies JE (2002) Plasma urotensin in
human systolic heart failure. Circulation 106:2877–2880.
Nilsson T, Arkhammar P, Rorsman P, and Berggren PO (1989) Suppression of insulin
release by galanin and somatostatin is mediated by a G-protein. An effect involving
repolarization and reduction in cytoplasmic free Ca2+ concentration. J Biol Chem
264:973–980.
Nishikawa N, Masuyama T, Yamamoto K, Sakata Y, Mano T, Miwa T, Sugawara M,
and Hori M (2001) Long-term administration of amlodipine prevents de-
compensation to diastolic heart failure in hypertensive rats. J Am Coll Cardiol 38:
1539–1545.
Nobata S, Donald JA, Balment RJ, and Takei Y (2011) Potent cardiovascular effects
of homologous urotensin II (UII)-related peptide and UII in unanesthetized eels
after peripheral and central injections. Am J Physiol Regul Integr Comp Physiol
300:R437–R446.
Nothacker HP and Clark S (2005) From heart to mind. The urotensin II system and
its evolving neurophysiological role. FEBS J 272:5694–5702.
Nothacker HP, Wang Z, McNeill AM, Saito Y, Merten S, O’Dowd B, Duckles SP,
and Civelli O (1999) Identification of the natural ligand of an orphan G-protein-
coupled receptor involved in the regulation of vasoconstriction. Nat Cell Biol 1:
383–385.
Oguri M, Kato K, Yokoi K, Itoh T, Yoshida T, Watanabe S, Metoki N, Yoshida H,
Satoh K, Aoyagi Y, et al. (2009) Association of genetic variants with myocardial
infarction in Japanese individuals with metabolic syndrome. Atherosclerosis 206:
486–493.
Ohsako S, Ishida I, Ichikawa T, and Deguchi T (1986) Cloning and sequence analysis
of cDNAs encoding precursors of urotensin II-alpha and -gamma. J Neurosci 6:
2730–2735.
Oka S, Honma Y, Iwanaga T, and Fujita T (1989) Immunohistochemical demonstration
of urotensins I and II in the caudal neurosecretory system of the white sturgeon,
Acipender transmontanus Richardson. Biomed Res 10 (Suppl 3):329–340.
Okumus S, Igci YZ, Taskin T, Oztuzcu S, Gurler B, Eslik Z, Gogebakan B, Coskun E,
Erbagci I, Demiryurek S, et al. (2012) Association between Thr21Met and Ser89-
Asn polymorphisms of the urotensin-II (UTS2) gene, diabetes mellitus, and di-
abetic retinopathy. Curr Eye Res 37:921–929.
Onan D, Hannan RD, and Thomas WG (2004a) Urotensin II: the old kid in town.
Trends Endocrinol Metab 15:175–182.
Onan D, Pipolo L, Yang E, Hannan RD, and Thomas WG (2004b) Urotensin II pro-
motes hypertrophy of cardiac myocytes via mitogen-activated protein kinases. Mol
Endocrinol 18:2344–2354.
Onat AM, Pehlivan Y, Turkbeyler IH, Demir T, Kaplan DS, Ceribasi AO, Orkmez M,
Tutar E, Taysi S, Sayarlioglu M, et al. (2013) Urotensin inhibition with palosuran
could be a promising alternative in pulmonary arterial hypertension. Inflammation
36:405–412.
Ong KL, Lam KS, and Cheung BM (2005) Urotensin II: its function in health and its
role in disease. Cardiovasc Drugs Ther 19:65–75.
Ong KL, Wong LY, and Cheung BM (2008) The role of urotensin II in the metabolic
syndrome. Peptides 29:859–867.
Ong KL, Wong LY, Man YB, Leung RY, Song YQ, Lam KS, and Cheung BM (2006)
Haplotypes in the urotensin II gene and urotensin II receptor gene are associated
with insulin resistance and impaired glucose tolerance. Peptides 27:1659–1667.
Ono T, Kawaguchi Y, Kudo M, Kushikata T, Hashiba E, Yoshida H, Kudo T,
Furukawa K, Douglas SA, Guerrini R, et al. (2008) Urotensin II evokes neuro-
transmitter release from rat cerebrocortical slices. Neurosci Let t 440:275–279.
Onstott D and Elde R (1986) Immunohisto chemical lo calizatio n of urotensin
I/corticotropin-releasing factor, urotensin II, and serotonin immunoreactivities in the
caudal spinal cord of nonteleost fishes. J Comp Neurol 249:205–225.
Owada K, Kawata M, Akaji K, Takagi A, Moriga M, and Kobayashi H (1985) Uro-
tensin II-immunoreactive neurons in the caudal neurosecretory system of fresh-
water and seawater fish. Cell Tissue Res 239:349–354.
Pakala R (2008) Role of urotensin II in atherosclerotic cardiovascular diseases.
Cardiovasc Revasc Med 9:166–178.
Papadopoulos P, Bousette N, and Giaid A (2008) Urotensin-II and cardiovascular
remodeling. Peptides 29:764–769.
Parmentier C, Hameury E, Dubessy C, Quan FB, Habert D, Calas A, Vaudry H,
Lihrmann I, and Tostivint H (2011) Occurrence of two distinct urotensin II-related
peptides in zebrafish provides new insight into the evolutionary history of the
urotensin II gene family. Endocrinology 152:2330–2341.
Parmentier C, Taxi J, Balment R, Nicolas G, and Calas A (2006) Caudal neurose-
cretory system of the zebrafish: ultrastructural organization and immunocyto-
chemical detection of urotensins. Cell Tissue Res 325:111–124.
Parys JB and De Smedt H (2012) Inositol 1,4,5-trisphosphate and its receptors. Adv
Exp Med Biol 740:255–279.
Patacchini R, Santicioli P, Giuliani S, Grieco P, Novellino E, Rovero P, and Maggi CA
(2003) Urantide: an ultrapotent urotensin II antagonist peptide in the rat aorta.
Br J Pharmacol 140:1155–1158.
Paysant J, Rupin A, Simonet S, Fabiani JN, and Verbeuren TJ (2001) Comparison of
the contractile responses of human coronary bypass grafts and monkey arteries to
human urotensin-II. Fundam Clin Pharmacol 15:227–231.
Pearson D, Shively JE, Clark BR, Geschwind II, Barkley M, Nishioka RS, and Bern
HA (1980) Urotensin II: a somatostatin-like peptide in the caudal neurosecretory
system of fishes. Proc Natl Acad Sci USA 77:5021–5024.
Pelletier G, Lihrmann I, Dubessy C, Luu-The V, Vaudry H, and Labrie F (2005)
Androgenic down-regulation of urotensin II precursor, urotensin II-related peptide
precursor and androgen receptor mRNA in the mouse spinal cord. Neuroscience
132:689–696.
Pelletier G, Lihrmann I, and Vaudry H (2002) Role of androgens in the regulation of
urotensin II precursor mRNA expression in the rat brainstem and spinal cord.
Neuroscience 115:525–532.
Perkins TD, Bansal S, and Barlow DJ (1990) Molecular modelling and design of
analogues of the peptide hormone urotensin II. Biochem Soc Trans 18:918–919.
Petersen TN, Brunak S, von Heijne G, and Nielsen H (2011) SignalP 4.0: discrimi-
nating signal peptides from transmembrane regions. Nat Methods 8:785–786.
Phelps PE, Barber RP, and Vaughn JE (1988) Generation patterns of four groups of
cholinergic neurons in rat cervical spinal cord: a combined tritiated thymidine
autoradiographic and choline acetyltransferase immunocytochemical study. JComp
Neurol 273:459–472.
Portnoy A, Kumar S, Behm DJ, Mahar KM, Noble RB, Throup JP, and Russ SF
(2013) Effects of urotensin II receptor antagonist, GSK1440115, in asthma. Front
Pharmacol 4:54.
Preininger AM, Meiler J, and Hamm HE (2013) Conformational flexibility and
structural dynamics in GPCR-mediated G protein activation: a perspective. J Mol
Biol 425:2288–2298.
Prosser HC, Forster ME, Richards AM, and Pemberton CJ (2008) Urotensin II and
urotensin II-related peptide (URP) in cardiac ischemia-reperfusion injury. Peptides
29:770–777.
Prosser HC, Leprince J, Vaudry H, Richards AM, Forster ME, and Pemberton CJ
(2006) Cardiovascular effects of native and non-native urotensin II and urotensin
II-related peptide on rat and salmon hearts. Peptides 27:3261–3268.
Qi J, Du J, Tang X, Li J, Wei B, and Tang C (2004) The upregulation of endothelial
nitric oxidesynthase and urotensin-II is associated with pulmonary hypertension and
vascular diseases in rats produced by aortocaval shunting. Heart Vessels 19:81–88.
Qi JS, Minor LK, Smith C, Hu B, Yang J, Andrade-Gordon P, and Damiano B (2005)
Characterization of functional urotensin II receptors in human skeletal muscle
myoblasts: comparison with angiotensin II receptors. Peptides 26:683–690.
Quan FB, Bougerol M, Rigour F, Kenigfest NB, and Tostivint H (2012) Character-
ization of the true ortholog of the urotensin II-related peptide (URP) gene in tel-
eosts. Gen Comp Endocrinol 177:205–212.
Quattrochi JJ, Mamelak AN, Madison RD, Macklis JD, and Hobson JA (1989)
Mapping neuronal inputs to REM sleep induction sites with carbachol-fluorescent
microspheres. Science 245:984–986.
Rdzanek A, Filipiak KJ, Karpi
nski G, Grabowski M, and Opolski G (2006) Exercise
urotensin II dynamics in myocardial infarction survivors with and without hy-
pertension. Int J Cardiol 110:175–178.
Richards AM, Nicholls MG, Lainchbury JG, Fisher S, and Yandle TG (2002) Plasma
urotensin II in heart failure. Lancet 360:545–546.
Rivas RJ, Nishioka RS, and Bern HA (1986) In vitro effects of somatostatin and
urotensin II on prolactin and growth hormone secretion in tilapia, Oreochromis
mossambicus. Gen Comp Endocrinol 63:245–251.
Rodríguez-Moyano M, Díaz I, Dionisio N, Zhang X, Avila-Medina J, Calderón-Sánchez
E, Trebak M, Rosado JA, Ordóñez A, and Smani T (2013) Urotensin-II promotes
vascular smooth muscle cell proliferation through store-operated calcium entry and
EGFR transactivation. Cardiovasc R es 100:297–306.
Romanova EV, Sasaki K, Alexeeva V, Vilim FS, Jing J, Richmond TA, Weiss KR,
and Sweedler JV (2012) Urotensin II in invertebrates: from structure to function in
Aplysia californica. PLoS ONE 7:e48764.
256 Vaudry et al.
Rossowski WJ, Cheng BL, Taylor JE, Datta R, and Coy DH (2002) Human urotensin
II-induced aorta ring contractions are mediated by protein kinase C, tyrosine
kinases and Rho-kinase: inhibition by somatostatin receptor antagonists. Eur J
Pharmacol 438:159–170.
Russell FD (2004) Emerging roles of urotensin-II in cardiovascular disease. Phar-
macol Ther 103:223–243.
Russell FD (2008) Urotensin II in cardiovascular regulation. Vasc Health Risk Manag
4:775–785.
Russell FD, Kearns P, Toth I, and Molenaar P (2004) Urotensin-II-converting enzyme
activity of furin and trypsin in human cells in vitro. J Pharmacol Exp Ther 310:
209–214.
Russell FD, Meyers D, Galbraith AJ, Bett N, Toth I, Kearns P, and Molenaar P (2003)
Elevated plasma levels of human urotensin-II immunoreactivity in congestive
heart failure. Am J Physiol Heart Circ Physiol 285:H1576–H1581.
Russell FD and Molenaar P (2004) Cardiovascular actions of human urotensin
II—considerations forhypertension.Naunyn Schmiedebergs Arch Pharmacol
369:271–273.
RussellFD,MolenaarP,andO’Brien DM (2001) Cardiostimulant effects of
urotensin-II in human heart in vitro. Br J Pharmacol 132:5–9.
Saetrum Opgaard O, Nothacker H, Ehlert FJ, and Krause DN (2000) Human uro-
tensin II mediates vasoconstriction via an increase in inositol phosphates. Eur J
Pharmacol 406:265–271.
Sáez ME, Smani T, Ramírez-Lorca R, Díaz I, Serrano-Ríos M, Ruiz A, and Ordoñez A
(2011) Association analysis of urotensin II gene (UTS2) and flanking regions with
biochemical parameters related to insulin resistance. PLoS ONE 6:e19327.
Sainsily X, Cabana J, Boulais PE, Holleran BJ, Escher E, Lavigne P, and Leduc R
(2013) Identification of transmembrane domain 3, 4 & 5 residues that contribute to
the formation of the ligand-binding pocket of the urotensin-II receptor. Biochem
Pharmacol 86:1584–1593.
Sauzeau V, Le Mellionnec E, Bertoglio J, Scalbert E, Pacaud P, and Loirand G (2001)
Human urotensin II-induced contraction and arterial smooth muscle cell pro-
liferation are mediated by RhoA and Rho-kinase. Circ Res 88:1102–1104.
Sawada M and Ichinose M (1999) Potentiation of GABA(A) receptor-mediated
Cl-current by urotensin peptides in identified Aplysia neurons. J Neurosci Res 56:
547–552.
Schlüter H, Jankowski J, Rykl J, Thiemann J, Belgardt S, Zidek W, Wittmann B,
and Pohl T (2003) Detection of protease activities with the mass-spectrometry-
assisted enzyme-screening (MES) system. Anal Bioanal Chem 377:1102–1107.
Segain JP, Rolli-Derkinderen M, Gervois N, Raingeard de la Blétière D, Loirand G,
and Pacaud P (2007) Urotensin II is a new chemotactic factor for UT receptor-
expressing monocytes. J Immunol 179:901–909.
Seidah NG, Sadr MS, Chrétien M, and Mbikay M (2013) The multifaceted proprotein
convertases: their unique, redundant, complementary, and opposite functions.
J Biol Chem 288:21473–21481.
Shapiro MD, Kronenberg Z, Li C, Domyan ET, Pan H, Campbell M, Tan H, Huff CD,
Hu H, Vickrey AI, et al. (2013) Genomic diversity and evolution of the head crest in
the rock pigeon. Science 339:1063–1067.
Sharp GW (1996) Mechanisms of inhibition of insulin release. Am J Physiol 271:
C1781–C1799.
Shenouda A, Douglas SA, Ohlstein EH, and Giaid A (2002) Localization of urotensin-
II immunoreactivity in normal human kidneys and renal carcinoma. J Histochem
Cytochem 50:885–889.
Sheridan MA, Plisetskaya EM, Bern HA, and Gorbman A (1987) Effects of
somatostatin-25 and urotensin II on lipid and carbohydrate metabolism of coho
salmon, Oncorhynchus kisutch. Gen Comp Endocrinol 66:405–414.
Sidharta PN, Rave K, Heinemann L, Chiossi E, Krähenbühl S, and Dingemanse J
(2009) Effect of the urotensin-II receptor antagonist palosuran on secretion of and
sensitivity to insulin in patients with Type 2 diabetes mellitus. Br J Clin Phar-
macol 68:502–510.
Sidharta PN, Wagner FD, Bohnemeier H, Jungnik A, Halabi A, Krähenbühl S,
Chadha-Boreham H, and Dingemanse J (2006) Pharmacodynamics and pharma-
cokinetics of the urotensin II receptor antagonist palosuran in macroalbuminuric,
diabetic patients. Clin Pharmacol Ther 80:246–256.
Silvestre RA, Egido EM, Hernández R, Leprince J, Chatenet D, Tollemer H, Chartrel
N, Vaudry H, and Marco J (2004) Urotensin-II is present in pancreatic extracts and
inhibits insulin release in the perfused rat pancreas. Eur J Endocrinol 151:
803–809.
Silvestre RA, Egido EM, Hernández R, and Marco J (2009) Characterization of the
insulinostatic effect of urotensin II: a study in the perfused rat pancreas. Regul
Pept 153:37–42.
Silvestre RA, Miralles P, Moreno P, Villanueva ML, and Marco J (1986) Somatostatin,
insulin and glucagon secretion by the perfused pancreas from the cysteamine-treated
rat. Biochem Biophys Res Commun 134:1291–1297.
Silvestre RA, Rodríguez-Gallardo J, Egido EM, and Marco J (2001) Inhibition of
insulin release by urotensin II—a study on the perfused rat pancreas. Horm Metab
Res 33:379–381.
Singh S, Robinson M, Ismail I, Saha M, Auer H, Kornacker K, Robinson ML, Bates
CM, and McHugh KM (2008) Transcriptional profiling of the megabladder mouse:
a unique model of bladder dysmorphogenesis. Dev Dyn 237:170–186.
Song W, Abdel-Razik AE, Lu W, Ao Z, Johns DG, Douglas SA, Balment RJ,
and Ashton N (2006a) Urotensin II and renal function in the rat. Kidney Int 69:
1360–1368.
Song W, McDonald J, Camarda V, Calo G, Guerrini R, Marzola E, Thompson JP,
Rowbotham DJ, and Lambert DG (2006b) Cell and tissue responses of a range of
Urotensin II analogs at cloned and native urotensin II receptors. Evidence for
coupling promiscuity. Naunyn Schmiedebergs Arch Pharmacol 373:148–157.
Spinazzi R, Albertin G, Nico B, Guidolin D, Di Liddo R, Rossi GP, Ribatti D,
and Nussdorfer GG (2006) Urotensin-II and its receptor (UT-R) are expressed in
rat brain endothelial cells, and urotensin-II via UT-R stimulates angiogenesis in
vivo and in vitro. Int J Mol Med 18:1107–1112.
Steriade M and McCarley R (1990) Brainstem control of wakefulness and sleep,
Plenum Press, New York.
Stirrat A, Gallagher M, Douglas SA, Ohlstein EH, Berry C, Kirk A, Richardson M,
and MacLean MR (2001) Potent vasodilator responses to human urotensin-II in
human pulmonary and abdominal resistance arteries. Am J Physiol Heart Circ
Physiol 280:H925–H928.
Sugden PH, Fuller SJ, Weiss SC, and Clerk A (2008) Glycogen synthase kinase 3
(GSK3) in the heart: a point of integration in hypertrophic signalling and a thera-
peutic target? A critical analysis. Br J Pharmacol 153 (Suppl 1):S137–S153.
Sugo T, Murakami Y, Shimomura Y, Harada M, Abe M, Ishibashi Y, Kitada C,
Miyajima N, Suzuki N, Mori M, et al. (2003) Identification of urotensin II-related
peptide as the urotensin II-immunoreactive molecule in the rat brain. Biochem
Biophys Res Commun 310:860–868.
Suguro T, Watanabe T, Kodate S, Xu G, Hirano T, Adachi M, and Miyazaki A (2008)
Increased plasma urotensin-II levels are associated with diabetic retinopathy and
carotid atherosclerosis in Type 2 diabetes. Clin Sci (Lond) 115:327–334.
Sun C, Duan D, Li B, Qin C, Jia J, Wang B, Dong H, and Li W (2014) UII and UT in
grouper: cloning and effects on the transcription of hormones related to growth
control. J Endocrinol 220:35–48.
Sun HX, Du WN, Zuo J, Wu GD, Shi GB, Shen Y, Qiang BQ, Yao ZJ, Hang JM, Wang
H, et al. (2002) The association of two single nucleotide polymorphisms in PRKCZ
and UTS2 respectively with type 2 diabetes in Han people of northern China.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao 24:223–227.
Suzuki S, Wenyi Z, Hirai M, Hinokio Y, Suzuki C, Yamada T, Yoshizumi S, Suzuki M,
Tanizawa Y, Matsutani A, et al. (2004) Genetic variations at urotensin II and
urotensin II receptor genes and risk of type 2 diabetes mellitus in Japanese.
Peptides 25:1803–1808.
Takahashi K, Totsune K, Murakami O, Arihara Z, Noshiro T, Hayashi Y,
and Shibahara S (2003) Expression of urotensin II and its receptor in adrenal
tumors and stimulation of proliferation of cultured tumor cells by urotensin II.
Peptides 24:301–306.
Takahashi K, Totsune K, Murakami O, and Shibahara S (2001) Expression of uro-
tensin II and urotensin II receptor mRNAs in various human tumor cell lines and
secretion of urotensin II-like immunoreactivity by SW-13 adrenocortical carcinoma
cells. Peptides 22:1175–1179.
Takei Y, Hyodo S, Katafuchi T, and Minamino N (2004a) Novel fish-derived adre-
nomedullin in mammals: structure and possible function. Peptides 25:1643–1656.
Takei Y, Inoue K, Ogoshi M, Kawahara T, Bannai H, and Miyano S (2004b) Identi-
fication of novel adrenomedullin in mammals: a potent cardiovascular and renal
regulator. FEBS Lett 556:53–58.
Tal M, Ammar DA, Karpuj M, Krizhanovsky V, Naim M, and Thompson DA (1995) A
novel putative neuropeptide receptor expressed in neural tissue, including sensory
epithelia. Biochem Biophys Res Commun 209:752–759.
Tamura K, Okazaki M, Tamura M, Isozumi K, Tasaki H, and Nakashima Y (2003)
Urotensin II-induced activation of extracellular signal-regulated kinase in cultured
vascular smooth muscle cells: involvement of cell adhesion-mediated integrin sig-
naling. Life Sci 72:1049–1060.
Tan YJ, Fan ZT, and Yang HX (2006) Role of urotensin II gene in the genetic sus-
ceptibility to gestational diabetes mellitus in northern Chinese women. Zhonghua
Fu Chan Ke Za Zhi 41:732–735.
Tarui N, Santo T, Mori M, and Watanabe H (2001) inventors, Takeda Chemical In-
dustries, Ltd., assignee. Quinoline derivatives as vasoactive agents exhibiting orphan
receptor GPR14 protein antagonism. Patent WO 2001-066143. 2001 Sep 13.
Tarui N, Santo T, Watanabe H, Aso K, and Ishihara Y (2002) inventors, Takeda
Chemical Industries, Ltd., assignee. Preparation of 2,3,4,5-tetrahydro-1H-3-
benzazepine derivatives as GPR14 antagonists. Patent WO 2002002530. 2002 Jan 10.
Tasaki K, Hori M, Ozaki H, Karaki H, and Wakabayashi I (2004) Mechanism of
human urotensin II-induced contraction in rat aorta. J Pharmacol Sci 94:376–383.
Thompson JP, Watt P, Sanghavi S, Strupish JW, and Lambert DG (2003) A com-
parison of cerebrospinal fluid and plasma urotensin II concentrations in normo-
tensive and hypertensive patients undergoing urological surgery during spinal
anesthesia: a pilot study. Anesth Analg 97:1501–1503.
Tian L, Li C, Qi J, Fu P, Yu X, Li X, and Cai L (2008) Diabetes-induced upregulation
of urotensin II and its receptor plays an important role in TGF-beta1-mediated
renal fibrosis and dysfunction. Am J Physiol Endocrinol Metab 295:E1234–E1242.
Tostivint H, Joly L, Lihrmann I, Ekker M, and Vaudry H (2004) Chromosomal lo-
calization of three somatostatin genes in zebrafish. Evidence that the [Pro2]-
somatostatin-14 isoform and cortistatin are encoded by orthologous genes. J Mol
Endocrinol 33:R1–R8.
Tostivint H, Joly L, Lihrmann I, Parmentier C, Lebon A, Morisson M, Calas A, Ekker
M, and Vaudry H (2006) Comparative genomics provides evidence for close evo-
lutionary relationships between the urotensin II and somatostatin gene families.
Proc Natl Acad Sci USA 103:2237–2242.
Tostivint H, Lihrmann I, and Vaudry H (2008) New insight into the molecular evo-
lution of the somatostatin family. Mol Cell Endocrinol 286:5–17.
Tostivint H, Ocampo Daza D, Bergqvist CA, Quan FB, Bougerol M, Lihrmann I,
and Larhammar D (2014) Molecular evolution of GPCRs: Somatostatin/urotensin
II receptors. J Mol Endocrinol 52:T61–T86.
Tostivint H, Quan FB, Bougerol M, Kenigfest NB, and Lihrmann I (2013) Impact of
gene/genome duplications on the evolution of the urotensin II and somatostatin
families. Gen Comp Endocrinol 188:110–117.
Totsune K, Takahashi K, Arihara Z, Sone M, Ito S, and Murakami O (2003) Increased
plasma urotensin II levels i n patients with diabetes mellitus. Clin Sci (Lond) 104:1–5.
Totsune K, Takahashi K, Arihara Z, Sone M, Murakami O, Ito S, Kikuya M, Ohkubo T,
Hashimoto J, and Imai Y (2004) Elevated plasma levels of immunoreactive urotensin
II and its increased urinary excretion in patients with Type 2 diabetes mellitus:
association with progress of diabetic nephropathy. Peptides 25:1809–1814.
Totsune K, Takahashi K, Arihara Z, Sone M, Satoh F, Ito S, Kimura Y, Sasano H,
and Murakami O (2001) Role of urotensin II in patients on dialysis. Lancet 358:
810–811.
Urotensin II and Its Receptor 257
Trebicka J, Leifeld L, Hennenberg M, Biecker E, Eckhardt A, Fischer N, Pröbsting
AS, Clemens C, Lammert F, Sauerbruch T, et al. (2008) Hemodynamic effects of
urotensin II and its specific receptor antagonist palosuran in cirrhotic rats. Hep-
atology 47:1264–1276.
Tsai CS, Loh SH, Liu JC, Lin JW, Chen YL, Chen CH, and Cheng TH (2009) Uro-
tensin II-induced endothelin-1 expression and cell proliferation via epidermal
growth factor receptor transactivation in rat aortic smooth muscle cells. Athero-
sclerosis 206:86–94.
Tsoukas P, Kane E, and Giaid A (2011) Potential clinical implications of the uro-
tensin II receptor antagonists. Front Pharmacol 2:38 10.3389/fphar.2011.00038.
Tsutsui K, Saigoh E, Ukena K, Teranishi H, Fujisawa Y, Kikuchi M, Ishii S,
and Sharp PJ (2000) A novel avian hypothalamic peptide inhibiting gonadotropin
release. Biochem Biophys Res Commun 275:661–667.
Tzanidis A, Hannan RD, Thomas WG, Onan D, Autelitano DJ, See F, Kelly DJ,
Gilbert RE, and Krum H (2003) Direct actions of urotensin II on the heart:
implications for cardiac fibrosis and hypertrophy. Circ Res 93:246–253.
Vale W, Spiess J, Rivier C, and Rivier J (1981) Characterization of a 41-residue ovine
hypothalamic peptide that stimulates secretion of corticotropin and beta-endor-
phin. Science 213:1394–1397.
Van de Peer Y, Maere S, and Meyer A (2010) 2R or not 2R is not the question
anymore. Nat Rev Genet 11:166.
Vaudry H, Chartrel N, and Conlon JM (1992) Isolation of [Pro2,Met13]somatostatin-
14 and somatostatin-14 from the frog brain reveals the existence of a somatostatin
gene family in a tetrapod. Biochem Biophys Res Commun 188:477–482.
Vaudry H and Conlon JM (1991) Identification of a peptide arising from the specific
post-translation processing of secretogranin II. FEBS Lett 284:31–33.
Vaudry H, Do Rego JC, Le Mével JC, Chatenet D, Tostivint H, Fournier A, Tonon
MC, Pelletier G, Conlon JM, and Leprince J (2010) Urotensin II, from fish to
human. Ann N Y Acad Sci 1200:53–66.
Vaughan J, Donaldson C, Bittencourt J, Perrin MH, Lewis K, Sutton S, Chan R,
Turnbull AV, Lovejoy D, Rivier C, et al. (1995) Urocortin, a mammalian neuropeptide
related to fish urotensin I and to corticotropin-releasing factor. Nature 378:287–292.
Vaughan JM, Fischer WH, Hoeger C, Rivier J, and Vale W (1989) Characterization of
melanin-concentrating hormone from rat hypothalamus. Endocrinology 125:1660–1665.
Vergura R, Camarda V, Rizzi A, Spagnol M, Guerrini R, Calo’G, Salvadori S,
and Regoli D (2004) Urotensin II stimulates plasma extravasation in mice via UT
receptor activation. Naunyn Schmiedebergs Arch Pharmacol 370:347–352.
Vigh B and Vigh-Teichmann I (1998) Actual problems of the cerebrospinal fluid-
contacting neurons. Microsc Res Tech 41:57–83.
Vogt L, Chiurchiu C, Chadha-Boreham H, Danaietash P, Dingemanse J, Hadjadj S,
Krum H, Navis G, Neuhart E, Parvanova AI, et al.; PROLONG (PROteinuria
Lowering with urOteNsin receptor antaGonists) Study Group (2010) Effect of the
urotensin receptor antagonist palosuran in hypertensive patients with type 2 di-
abetic nephropathy. Hypertension 55:1206–1209.
Wang HX, Zeng XJ, Liu Y, Wang J, Lu LQ, Hao G, Zhang LK, and Tang CS (2009)
Elevated expression of urotensin II and its receptor in skeletal muscle of diabetic
mouse. Regul Pept 154:85–90.
Wang YX, Ding YJ, Zhu YZ, Shi Y, Yao T, and Zhu YC (2007) Role of PKC in the novel
synergistic action of urotensin II and angiotensin II and in urotensin II-induced
vasoconstriction. Am J Physiol Heart Circ Physiol 292:H348–H359.
Watanabe T, Pakala R, Katagiri T, and Benedict CR (2001a) Synergistic effect of
urotensin II with mildly oxidized LDL on DNA synthesis in vascular smooth
muscle cells. Circulation 104:16–18.
Watanabe T, Pakala R, Katagiri T, and Benedict CR (2001b) Synergistic effect of uro-
tensin II with serotonin on vascular smooth muscle cell proliferation. JHypertens19:
2191–2196.
Watanabe T, Suguro T, Kanome T, Sakamoto Y, Kodate S, Hagiwara T, Hongo S,
Hirano T, Adachi M, and Miyazaki A (2005) Human urotensin II accelerates foam
cell formation in human monocyte-derived macrophages. Hypertension 46:738–744.
Watson AM, Lambert GW, Smith KJ, and May CN (2003) Urotensin II acts centrally
to increase epinephrine and ACTH release and cause potent inotropic and chro-
notropic actions. Hypertension 42:373–379.
Watson AM and May CN (2004) Urotensin II, a novel peptide in central and pe-
ripheral cardiovascular control. Peptides 25:1759–1766.
Watson AM, McKinley MJ, and May CN (2008) Effect of central urotensin II on heart
rate, blood pressure and brain Fos immunoreactivity in conscious rats. Neurosci-
ence 155:241–249.
Watson AM, Olukman M, Koulis C, Tu Y, Samijono D, Yuen D, Lee C, Behm DJ,
Cooper ME, Jandeleit-Dahm KA, et al. (2013) Urotensin II receptor antagonism
confers vasoprotective effects in diabetes associated atherosclerosis: studies in
humans and in a mouse model of diabetes. Diabetologia 56:1155–1165.
Waugh D and Conlon JM (1993) Purification and characterization of urotensin II
from the brain of a teleost (trout, Oncorhynchus mykiss) and an elasmobranch
(skate, Raja rhina). Gen Comp Endocrinol 92:419–427.
Waugh D, Youson J, Mims SD, Sower S, and Conlon JM (1995) Urotensin II from the
river lamprey (Lampetra fluviatilis), the sea lamprey (Petromyzon marinus), and
the paddlefish (Polyodon spathula). Gen Comp Endocrinol 99:323–332.
Webster HH and Jones BE (1988) Neurotoxic lesions of the dorsolateral pontome-
sencephalic tegmentum-cholinergic cell area in the cat. II. Effects upon sleep-
waking states. Brain Res 458:285–302.
Wenyi Z, Suzuki S, Hirai M, Hinokio Y, Tanizawa Y, Matsutani A, Satoh J, and Oka
Y (2003) Role of urotensin II gene in genetic susceptibility to Type 2 diabetes
mellitus in Japanese subjects. Diabetologia 46:972–976.
Wilkinson IB, Affolter JT, de Haas SL, Pellegrini MP, Boyd J, Winter MJ, Balment
RJ, and Webb DJ (2002) High plasma concentrations of human urotensin II do not
alter local or systemic hemodynamics in man. Cardiovasc Res 53:341–347.
Wu YQ, Song Z, Zhou CH, Xing SH, Pei DS, and Zheng JN (2010) Expression of
urotensin II and its receptor in human lung adenocarcinoma A549 cells and the
effect of urotensin II on lung adenocarcinoma growth in vitro and in vivo. Oncol
Rep 24:1179–1184.
Xie N and Liu L (2009) Elevated expression of urotensin II and its receptor in great
artery of type 2 diabetes and its significance. Biomed Pharmacother 63:734–741.
Xu S, Wen H, and Jiang H (2012) Urotensin II promotes the proliferation of endo-
thelial progenitor cells through p38 and p44/42 MAPK activation. Mol Med Rep 6:
197–200.
Yano K, Hicks JW, Vaudry H, and Conlon JM (1995) Cardiovascular actions of frog
urotensin II in the frog, Rana catesbeiana. Gen Comp Endocrinol 97:103–110.
Yano K, Vaudry H, and Conlon JM (1994) Spasmogenic actions of frog urotensin II on
the bladder and ileum of the frog, Rana catesbeiana. Gen Comp Endocrinol 96:
412–419.
Yasuda T, Masaki T, Gotoh K, Chiba S, Kakuma T, and Yoshimatsu H (2012)
Intracerebroventricular administration of urotensin II regulates food intake and
sympathetic nerve activity in brown adipose tissue. Peptides 35:131–135.
You Z, Genest J Jr, Barrette PO, Hafiane A, Behm DJ, D’Orleans-Juste P,
and Schwertani AG (2012) Genetic and pharmacological manipulation of urotensin
II ameliorate the metabolic and atherosclerosis sequalae in mice. Arterioscler
Thromb Vasc Biol 32:1809–1816.
Yulis CR and Lederis K (1986) Extraurophyseal distribution of urotensin II immu-
noreactive neuronal perikarya and their processes. Proc Natl Acad Sci USA 83:
7079–7083.
Yulis CR and Lederis K (1988) Occurrence of an anterior spinal, cerebrospinal fluid-
contacting, urotensin II neuronal system in various fish species. Gen Comp
Endocrinol 70:301–311.
Zelnik PR and Lederis K (1973) Chromatographic separation of urotensins. Gen
Comp Endocrinol 20:392–400.
Zemancíková A and Török J (2013) Urotensin II—a newly discovered modulator of
cardiovascular functions in vertebrates. Cesk Fysiol 62:19–25.
Zeng ZP, Liu GQ, Li HZ, Fan XR, Liu DM, Tong AL, Zheng X, and Liu C (2006) The
effects of urotensin-II on proliferation of pheochromocytoma cells and mRNA ex-
pression of urotensin-II and its receptor in pheochromocytoma tissues. Ann N Y
Acad Sci 1073:284–289.
Zhang Y, Li J, Cao J, Chen J, Yang J, Zhang Z, Du J, and Tang C (2002) Effect of
chronic hypoxia on contents of urotensin II and its functional receptors in rat
myocardium. Heart Vessels 16:64–68.
Zhang YG, Li J, Li YG, and Wei RH (2008) Urotensin II induces phenotypic differ-
entiation, migration, and collagen synthesis of adventitial fibroblasts from rat
aorta. J Hypertens 26:1119–1126.
Zhang YG, Li YG, Liu BG, Wei RH, Wang DM, Tan XR, Bu DF, Pang YZ, and Tang
CS (2007) Urotensin II accelerates cardiac fibrosis and hypertrophy of rats induced
by isoproterenol. Acta Pharmacol Sin 28:36–43.
Zhou CH, Wan YY, Chu XH, Song Z, Xing SH, Wu YQ, and Yin XX (2012) Urotensin
II contributes to the formation of lung adenocarcinoma inflammatory microenvi-
ronment through the NF-kB pathway in tumor-bearing nude mice. Oncol Lett 4:
1259–1263.
Zhu F, Ji L, and Luo B (2002) The role of urotensin II gene in the genetic suscepti-
bility to type 2 diabetes in Chinese population. Zhonghua Yi Xue Za Zhi (Taipei)
82:1473–1475.
Ziltener P, Mueller C, Haenig B, Scherz MW, and Nayler O (2002) Urotensin II
mediates ERK1/2 phosphorylation and proliferation in GPR14-transfected cell
lines. J Recept Signal Transduct Res 22:155–168.
Zou Y, Nagai R, and Yamazaki T (2001) Urotensin II induces hypertrophic responses
in cultured cardiomyocytes from neonatal rats. FEBS Lett 508:57–60.
258 Vaudry et al.
