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Molecular structures of 3',5'-guanosine cyclic monophosphate (cGMP) and 3',5'-adenosine cyclic monophosphate (cAMP). Structures of the two molecules differ only in the pyrimidine rings and the positions of the ring are numbered 1-6.
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Cyclic GMP is a critical second messenger signaling molecule in many mammalian cell types. It is synthesized by a family of guanylyl cyclases that is activated in response to stimuli from hormones such as natriuretic peptides, members of the guanylin family, and chemical stimuli including nitric oxide and carbon monoxide. The resulting elevation of...
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Key points
Natriuretic peptides are powerful regulators of the cardiovascular system, but their direct electrophysiological effects in the heart are poorly understood.
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Nesiritide, a recombinant human B-type natriuretic peptide, is the first in a new drug class for the treatment of decompensated heart failure. The drug binds to receptors in the vasculature, kidney, adrenal gland, and brain, and overcomes resistance to endogenous BNP present in patients with CHF. Nesiritide administration leads to a rapid and balan...
It remains uncertain whether angiotensin converting enzyme (ACE) inhibitors benefit all heart failure patients or just those with renin-angiotensin-aldosterone system (RAAS) activation.
To determine whether the response to an ACE inhibitor, assessed by urine sodium excretion, was different in patients with low renin versus those with high renin.
Pl...
Citations
... The presence of cGMP-interacting proteins can be studied using, for example, proteomics, and previous such investigations have indeed resulted in the discovery of such proteins in multiple tissues (Kim & Park, 2003;Scholten et al., 2006Scholten et al., , 2007. Regular cG-MP-interacting proteins include PKG (Corradini et al., 2015;Francis et al., 2005;Francis & Corbin, 2013;Paquet-Durand et al., 2009), and cAMP-dependent protein kinase (PKA), which shares homology with PKG (Francis & Corbin, 2013) and which can be cross-activated by cGMP, as well as CNG-channels, phosphodiesterases, and cGMP transport proteins (Francis et al., 2005). However, seemingly unrelated proteins have also been reported as potential interactors, like the mitogen-activated protein kinase I (MAPKI) (Kim & Park, 2003). ...
... The presence of cGMP-interacting proteins can be studied using, for example, proteomics, and previous such investigations have indeed resulted in the discovery of such proteins in multiple tissues (Kim & Park, 2003;Scholten et al., 2006Scholten et al., , 2007. Regular cG-MP-interacting proteins include PKG (Corradini et al., 2015;Francis et al., 2005;Francis & Corbin, 2013;Paquet-Durand et al., 2009), and cAMP-dependent protein kinase (PKA), which shares homology with PKG (Francis & Corbin, 2013) and which can be cross-activated by cGMP, as well as CNG-channels, phosphodiesterases, and cGMP transport proteins (Francis et al., 2005). However, seemingly unrelated proteins have also been reported as potential interactors, like the mitogen-activated protein kinase I (MAPKI) (Kim & Park, 2003). ...
The hereditary disease Retinitis pigmentosa results in severe vision loss due to photoreceptor degeneration by unclear mechanisms. In several disease models, the second messenger cGMP accumulates in the degenerating photoreceptors, where it may over‐activate specific cGMP‐interacting proteins, like cGMP‐dependent protein kinase. Moreover, interventions that counteract the activity of these proteins lead to reduced photoreceptor cell death. Yet there is little or no information whether other than such regular cGMP‐interactors are present in the retina, which we, therefore, investigated in wild‐type and retinal degeneration (rd1, rd10, and rd2) mouse models. An affinity chromatography based proteomics approach that utilized immobilized cGMP analogs was applied to enrich and select for regular and potentially new cGMP‐interacting proteins as identified by mass spectrometry. This approach revealed 12 regular and 10 potentially new retinal cGMP‐interacting proteins (e.g., EPAC2 and CaMKIIα). Several of the latter were found to be expressed in the photoreceptors and to have proximity to cGMP and may thus be of interest when defining prospective therapeutic targets or biomarkers for retinal degeneration.
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... 21 The probable mechanism by which PDE5 inhibitors decrease these LUTS is that nitric oxide enters the smooth muscles and stimulates guanosinecyclase that converts cyclic guanosine three phosphate to cGMP, which in turn decreases intracellular calcium concentration and consequently causes muscle relaxation. 21,22 Latest evidence on pathophysiology of LUTS has provided the rationale for use of PDE5 for (1) improvement of lower urinary tract oxygenation, (2) negative regulation of proliferation and trans-differentiation of lower urinary tract stroma,(3) reduction in bladder afferent nerve activity, and (4) downregulation of prostate inflammation Tadalafil and other PDE5 inhibitors have demonstrated beneficial effects on smooth muscle relaxation, endothelial cell proliferation, nerve activity, and tissue perfusion that may impact LUTS in men. 21 A 20-mg once-daily dose of PDE5 inhibitor such as tadalafil is well tolerated and has shown clinically meaningful and statistically significant efficacy in men with benign prostatic hyperplasia (BPH) and LUTS. ...
Objective To analyze role of phosphodiesterase 5 (PDE5) inhibitors on urodynamic parameters in patients with suprasacral spinal cord injury.
Materials and Methods This was a prospective observational hospital-based study conducted on a cohort of patients, aged between 18 and 65 years with suprasacral spinal cord injury, who were registered in Department of Neurosurgery/Urology. Cutoff period since injury was 2 years. After taking consent, baseline urodynamic study was performed, which was repeated 2 hours after taking single oral dose of 20 mg tadalafil. Urodynamic parameters such as maximum detrusor filling/voiding pressures, maximum bladder capacity, and bladder compliance before and after taking drug were compared for final results and conclusion.
Results Following administration of 20 mg of tadalafil, maximum bladder capacity in mL showed statistically significant improvement from 268.39 ± 130.0 to 298.55 ± 112.0.(p < 0.05). Bladder compliance improved from 18.68 ± 6.4 to 20.25 ± 7.5 mL/cm H2O (p > 0.05). Maximum detrusor filling pressure improved from 36.03 ± 20.54 to 32.90 ± 16.47 cm H2O (p > 0.05). Maximum detrusor voiding pressure improved from 64.65 ± 33.19 to 58.13 ± 20.7 cm H2O (0 > 0.05). In patients with injury above D6 spinal cord level, statistically significant improvement was seen in maximum bladder capacity and bladder compliance after 2 hours of single oral dose of tadalafil (p < 0.05).
Conclusion Our study suggests a positive role of PDE inhibitors in improving urodynamic parameters in patients with suprasacral spinal cord injury with improvement in parameters such as bladder capacity, detrusor pressures, and bladder compliance. Because this is a small study group, more studies such as this are required to reach to final conclusion.
... There are two PKGs, PKG 1 and 2, encoded by two different genes. PKG1 has, moreover, two isoenzymes as consequence of alternative splicing (Francis et al. 2005). Both isoenzymes bind two cGMP molecules pro monomer and phosphorylate similar substrates with comparable affinity (Hofmann et al. 2009). ...
Hintergrund und Ziele. Die Systemische Sklerose (SSc) ist eine prototypische fibrosierende Erkrankung, gekennzeichnet durch hohe Morbidität und Mortalität. Effektive antifibrotische Therapien sind bis jetzt für die klinische Anwendung nicht vorhanden. Stimulatoren der löslichen Guanylylcyclase (lGC, englisch sGC) werden derzeit in klinischen Studien für die Behandlung von Fibrose in SSc untersucht. Ziel dieser Arbeit war die Untersuchung der Rolle von Proteinkinasen G (PKG) als nachgeschaltete Mediatoren der sGC und des cyclischen Guanosinmonophosphat (cGMP) sowie die Charakterisierung der Fehlregulierung dieses Signalweges in SSc. Methoden. Zur Bestimmung der Expression von Proteinkinasen G 1 und 2, von sGC und von p-VASP und VASP wurden Immunfluoreszenz und/oder Western Blot eingesetzt, zur Bestimmung des Spiegels von intrazellulärem cGMP wurde ein ELISA Kit verwendet. Die Spiegel der oben genannten Proteine und Mediatoren in der Haut oder in kultivierten dermalen Fibroblasten bei gesunden Spendern wurden mit denen bei SSc Patienten verglichen. Kultivierte Fibroblasten von gesunden Spender, SSc Patienten oder PKG1 und 2 – Doppel-Knockout Mäusen wurden mit TGF-β1 und/oder dem sGC-Stimulator BAY 41-2272, oder dem PKG-Inhibitor KT5823 behandelt. Bei den behandelten Fibroblasten wurde die Bildung von Stressfasern und die Menge von α-Smooth- 7 Muscle-Actin (α-SMA) Protein, von Col1a1 mRNA und Kollagen Typ 1 Protein untersucht. Bei knockout Mäusen für PKG1 und 2 oder für sGC wurde Bleomycin appliziert, und diese anschließend mit BAY 41-2272 behandelt. Um die Fibrosebildung bei diesen Mäusen zu bestimmen, wurde die Hautdicke vermessen, der Hydroxyprolingehalt bestimmt und die Myofibroblastenanzahl quantifiziert. Ergebnisse und Beobachtungen. Wir stellten eine Fehlregulierung des Signalwegs sGC-cGMP-PKG1 und 2 bei den Patienten mit SSc fest, die auf die erhöhten TGF-β1-Spiegel zurückzuführen zu sein scheint. sGC und cGMP sind bei SSc Patienten herunterreguliert. PKG1 und PKG2 sind hochreguliert, am ehesten als frustraner Kompensationsversuch. Die Fibroblastenaktivierung wird durch sGC Stimulierung und darauffolgende Hemmung der TGF-β1-induzierten ERK-Phosphorylierung gehemmt, wobei die Hemmung oder der Knockout der PKG1 und 2 den Effekt von sGC Stimulierung aufhebt. Behandlung mit sGC Stimulatoren schützt Wildtyp-Mäuse, aber nicht die PKG 1 und 2 Doppel-Knockout Mäuse vor der durch Bleomycin-induzierten Fibrose. Schlussfolgerungen. Aus unseren Daten können wir schließen, dass PKG 1 und 2 wesentliche nachgeschaltete Mediatoren der durch Hemmung der TGF-β1-induzierten ERK-Phosphorylierung hervorgerufenen antifibrotischen Effekte von sGC Stimulatoren sind. Wir zeigen außerdem eine geringere Aktivität des antifibrotischen sGC – cGMP – PKG 1 und 2 Signalwegs in SSc, die wahrscheinlich von TGF-β1 induziert wird.
... This implies that full-length PKG Ia only requires that half of the A-sites are occupied to stimulate full activation. These data, which also suggest the B-site is non-essential for kinase activity, are further supported by the fact that the K D for the B-site (⇠90 µM) is higher than estimated intracellular concentrations of cGMP (⇠10 nM -10 µM) (57)(58)(59). Moreover, we observe that mutation of the nucleotide binding cassette in the B-site does not appreciably a ect activation of the full-length kinase ( Figure S4). ...
The type I cGMP-dependent protein kinases serve essential physiological functions, including smooth muscle relaxation, cardiac remodeling, and platelet aggregation. These enzymes form homodimers through their N-terminal dimerization domains, a feature implicated in regulating their cooperative activation. Previous investigations into the activation mechanisms of PKG I isoforms have been largely influenced by structures of the cAMP-dependent protein kinase (PKA). Here, we examined PKG Iα activation by cGMP and cAMP by engineering a monomeric form that lacks N-terminal residues 1-53 (Δ53). We found that the construct exists as a monomer as assessed by whole-protein mass spectrometry, size-exclusion chromatography, and small-angle X-ray scattering (SAXS). Reconstruction of the SAXS 3D envelope indicates that Δ53 has a similar shape to the heterodimeric RIα:C complex of PKA. Moreover, we found that the Δ53 construct is autoinhibited in its cGMP-free state and can bind to and be activated by cGMP in a manner similar to full-length as assessed by surface plasmon resonance spectroscopy (SPR). However we found that the Δ53 variant does not exhibit cooperative activation, and its cyclic nucleotide selectivity is diminished. These findings support a model in which, despite structural similarities, PKG Iα activation is distinct from PKA, and its cooperativity is driven by in trans interactions between protomers.
... Such a mechanism of action remains to be tested in resistance artery VSMCs; however, although ATA reduced increases in global [Ca 2+ ] i to stimulation in isolated mesenteric arteries, this effect was prevented by LNNA or VLN, suggesting that its effects were due to nitric oxide per se rather than being PMCA-mediated. Indeed, it is wellestablished that nitric oxide, via its second messengers cGMP and PKG, can reduce [Ca 2+ ] i in vascular smooth muscle by mechanisms which include decreased Ca 2+ entry and reduced release from the sarcoplasmic reticulum [51][52][53]. This observation is consistent with the notion that inhibiting PMCA4 has no effects on global [Ca 2+ ] i and is consistent with the regulative mechanism in the heart, whereby PMCA4 regulates nNOS activity by physical tethering and regulation of subcellular Ca 2+ . ...
... That PMCA4 maintains the spatial and functional integrity of a signalling complex including nNOS in a defined plasma membrane microdomain [14,37,58] is well supported, but that its complete absence may cause disruption of the complex with nNOS being relocated to the cytosol remains to be fully elucidated. This would further promote an important role for PMCA4 as a scaffolding molecule in arterial tissue as has recently been discussed [51]. ...
Cardiovascular disease is the world's leading cause of morbidity and mortality, with high blood pressure (BP) contributing to increased severity and number of adverse outcomes. Plasma membrane calcium ATPase 4 (PMCA4) has been previously shown to modulate systemic BP. However, published data are conflicting, with both overexpression and inhibition of PMCA4 in vivo shown to increase arterial contractility. Hence, our objective was to determine the role of PMCA4 in the regulation of BP and to further understand how PMCA4 functionally regulates BP using a novel specific inhibitor to PMCA4, aurintricarboxylic acid (ATA). Our approach assessed conscious BP and contractility of resistance arteries from PMCA4 global knockout (PMCA4KO) mice compared to wild-type animals. Global ablation of PMCA4 had no significant effect on BP, arterial structure or isolated arterial contractility. ATA treatment significantly reduced BP and arterial contractility in wild-type mice but had no significant effect in PMCA4KO mice. The effect of ATAin vivo and ex vivo was abolished by the neuronal nitric oxide synthase (nNOS) inhibitor Vinyl-l-NIO. Thus, this highlights differences in the effects of PMCA4 ablation and acute inhibition on the vasculature. Importantly, for doses here used, we show the vascular effects of ATA to be specific for PMCA4 and that ATA may be a further experimental tool for elucidating the role of PMCA4.
... PDEmediated hydrolysis of intracellular cGMP is balanced by guanylate cyclase enzymes (GCs). Increased cGMP levels activate the PKGs and their downstream effectors [22]. Interestingly, the nitric oxide (NO)/cGMP/PKG system has been proposed to be involved in GBM stem cell expansion [23] and high levels of cGMP, as well as treatment with sildenafil, strongly enhance mouse GBM cancer stem cell phenotype in vitro and their tumorigenic potential in vivo [23]. ...
Expression of type 5 phosphodiesterase (PDE5), a cGMP-specific hydrolytic enzyme, is frequently altered in human cancer, but its specific role in tumorigenesis remains controversial. Herein, by analyzing a cohort of 69 patients affected by glioblastoma multiforme (GBM) who underwent chemo- and radiotherapy after surgical resection of the tumor, we found that PDE5 was strongly expressed in cancer cells in about 50% of the patients. Retrospective analysis indicated that high PDE5 expression in GBM cells significantly correlated with longer overall survival of patients. Furthermore, silencing of endogenous PDE5 by short hairpin lentiviral transduction (sh-PDE5) in the T98G GBM cell line induced activation of an invasive phenotype. Similarly, pharmacological inhibition of PDE5 activity strongly enhanced cell motility and invasiveness in T98G cells. This invasive phenotype was accompanied by increased secretion of metallo-proteinase 2 (MMP-2) and activation of protein kinase G (PKG). Moreover, PDE5 silencing markedly enhanced DNA damage repair and cell survival following irradiation. The enhanced radio-resistance of sh-PDE5 GBM cells was mediated by an increase of poly(ADP-ribosyl)ation (PARylation) of cellular proteins and could be counteracted by poly(ADP-ribose) polymerase (PARP) inhibitors. Conversely, PDE5 overexpression in PDE5-negative U87G cells significantly reduced MMP-2 secretion, inhibited their invasive potential and interfered with DNA damage repair and cell survival following irradiation. These studies identify PDE5 as a favorable prognostic marker for GBM, which negatively affects cell invasiveness and survival to ionizing radiation. Moreover, our work highlights the therapeutic potential of targeting PKG and/or PARP activity in this currently incurable subset of brain cancers.
... Cyclic nucleotide signaling is represented by a network that involves significant crosstalk in which these messengers modulate each other's synthesis, degradation, and effectors. 33,110,362 The primary effectors are PKA and PKG, and despite their names, these kinases are not wholly selective for the cyclic nucleotides for which they are named. Notably, cAMP can activate PKG, and the ability of the AC activator forskolin to cause reductions in VSM Ca 2+ entry is due to activation by cAMP of PKG, not PKA. ...
... 210,272,273 In addition to kinase activation, cyclic nucleotides regulate cyclic nucleotide phosphodiesterase activities, and can activate cyclic nucleotide-gated (CNG) Ca 2+ -permeable nonselective cation channels that, when expressed in endothelial cells cause relaxation and, when expressed in VSM, may enhance contraction. 110,271 Moreover, cAMP binds the exchange protein activated by cAMP (Epac) to elevate activity of ras family members, rap GTPases. 418 In VSM, the cAMP-Epac-rap signaling system causes relaxation by activation of rho-GAP. ...
... In 1998, phosphodiesterase type 5 inhibitors (PDE5Is) were first approved for the treatment of erectile dysfunction (ED). The mechanism of action of PDE5Is involves increasing the levels of the second messenger, cyclic guanosine monophosphate (cGMP), which induces penile erection through smooth muscle relaxation [5]. Theoretically, PDE5Is can increase the level of nitric oxide (NO) in smooth muscle, which mediates smooth muscle relaxation in the corpus cavernosum, thereby facilitating penile erection. ...
... Theoretically, PDE5Is can increase the level of nitric oxide (NO) in smooth muscle, which mediates smooth muscle relaxation in the corpus cavernosum, thereby facilitating penile erection. Additionally, NO can relax smooth muscles of voiding-related urological organs such as the bladder neck and prostate, eventually relieving BPH-related LUTS [3,5]. ...
Purpose:
Combination therapy with an α-1-adrenergic blocker and phosphodiesterase type 5 inhibitors (PDE5Is) has shown improvements in lower urinary tract symptoms (LUTS) with negligible side effects. Nonetheless, decisive advantages in symptom improvement were insufficient, and there were no clinical differences between long- or short-acting PDE5Is in combination with combination medication.
Methods:
To review the studies on α-1-adrenergic blocker monotherapy and combination therapy with long vs. short-acting PDE5Is in their use in LUTS and erectile dysfunction (ED). A search of the MEDLINE, Embase, Cochrane Library, and KoreaMed databases was conducted from 2000 to 2014 using combinations of the relevant terms. Among the 323 relevant references discovered, 10 were selected for meta-analysis. The data showed that 616 men received combination therapy (PDE5Is with α-1-adrenergic blockers) or α-1-adrenergic blocker monotherapy.
Results:
Meta-analysis of the combination therapy showed it was more effective than α-blockers in improving symptoms, with a mean International Prostrate Symptom Score change difference of -1.93 while those of the long- vs. short-acting PDE5I were -2.12 vs. -1.70. Compared to maximum flow rate (Qmax) value with monotherapy, the Qmax increased more with the combination therapy (mean difference of 0.71) while change values were 0.14 and 1.13 for the long- and short-acting PDE5Is, respectively. Residual urine decreased more with the combination therapy than it did with α-1-adrenergic blocker monotherapy with a mean difference of -7.09 while the mean residual urine change values for long- vs. short-acting PDE5Is were -18.83 vs. -5.93. The International Index of Erectile Function value increased by 3.99, 2.85, and 4.85 following combination therapy, and therapy with long- and short-acting PDE5Is.
Conclusions:
Our meta-analysis suggests that PDE5Is can significantly improve LUTS in men with benign prostatic hyperplasia/ED. Furthermore, combination PDE5I and α-1-adrenergic blocker could be a more effective treatment than α-1-adrenergic blocker monotherapy, and the differences between long and short-acting agents were minimal.
... A recent study has shown that PKG activity is both necessary and sufficient to cause cGMP-mediated photoreceptor degeneration and that PKG inhibitors are protective in rd1 retina [8]. Finally, high levels of cGMP may induce nonspecific crosstalk with cAMP signaling pathways [24,25]. Dopamine signaling acts directly through cAMP, modulating intracellular Ca 2+ and mediating anti-apoptotic activity in developing rat retina [10,26,27]. ...
The rd1 mouse is a model of retinitis pigmentosa, an inherited photoreceptor neurodegenerative disease. In rd1 retina, early onset rod degeneration is caused by a Pde6b mutation that leads to high levels of intracellular cyclic guanosine monophosphate (cGMP). Cyclic nucleotide-gated ion channels (CNGCs), necessary for phototransduction, are regulated by cGMP. We have previously demonstrated that inhibition of dopamine signaling blocks rd1 photoreceptor degeneration in retinal organ cultures. The mechanism underlying this protection remains unknown. The aim of this study was to determine whether inhibition of dopamine signaling alters cGMP accumulation or CNGC expression. Dopamine depletion from rd1 retinal organ cultures resulted in a significant decrease in cGMP compared with untreated rd1 organ cultures. However, cGMP levels in both treated and untreated rd1 organ cultures significantly exceeded cGMP levels in wild-type (wt) retinal organ cultures. The CNGC expression profile was first determined in vivo. Both channel subunits, Cnga1 and Cngb1, are expressed at low levels by postnatal day 2 (P2), increasing sharply by P6 with a modest increase after P12 in wt retina. A similar pattern is seen in rd1 retina until P12 when expression levels decrease, leading to cell death. No significant difference was observed in the expression of either Cnga1 or Cngb1 in organ cultures from wt, rd1, and dopamine-depleted rd1 retinas. Our results show that dopamine depletion significantly decreases cGMP levels in rd1 retinal organ cultures, but that cGMP accumulation remains high, requiring additional mechanisms for photoreceptor protection. These mechanisms may include activation of protein kinase G-signaling pathways and/or crosstalk with dopamine signaling through cyclic adenosine monophosphate pathways.
... (1H [1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one), an inhibitor of sGC, should be dissolved fresh on the day of use in DMSO, and kept on ice as a 10 mM stock. ODQ can be used in a working solution at 10 μM. ...
Real-time and noninvasive imaging of intracellular second messengers in mammalian cells, while -preserving their in vivo phenotype, requires biosensors of exquisite constitution. Here we provide the methodology for utilizing the single wavelength cGMP-biosensor δ-FlincG in aortic vascular smooth muscle cells.
