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DRIP is expressed in the MTs. A: DRIP mRNA in situ of late stage 17 embryo shows DRIP expression in the MT. The elongated stage 17 embryo (compare with stage 17 in Fig. 2B) will soon hatch as a first instar larva. B: DRIP mRNA in situ of a dissected adult MT. Note that DRIP expression is restricted to the stellate cells. Four experiments were performed with similar results.
Source publication
Aquaporins (AQPs) accelerate the movement of water and other solutes across biological membranes, yet the molecular mechanisms of each AQP's transport function and the diverse physiological roles played by AQP family members are still being defined. We therefore have characterized an AQP in a model organism, Drosophila melanogaster, which is amenab...
Contexts in source publication
Context 1
... mammalian AQPs regulate fluid homeostasis in the kidney (25), we examined DRIP expression in the embryonic and adult MTs. Indeed, DRIP was expressed in the MTs of late stage 17 embryos that are about to eclose as first instar larvae (Fig. 3A). We also found DRIP expression in the adult MTs, although expression is clearly restricted to stellate cells (Fig. 3B), including the bar-shaped stellate cells in the distal MT (data not shown). This expression pattern is different from the pattern exhibited by an Aedes aegypti DRIP homolog; in this organism, the message resides in the ...
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... AQPs regulate fluid homeostasis in the kidney (25), we examined DRIP expression in the embryonic and adult MTs. Indeed, DRIP was expressed in the MTs of late stage 17 embryos that are about to eclose as first instar larvae (Fig. 3A). We also found DRIP expression in the adult MTs, although expression is clearly restricted to stellate cells (Fig. 3B), including the bar-shaped stellate cells in the distal MT (data not shown). This expression pattern is different from the pattern exhibited by an Aedes aegypti DRIP homolog; in this organism, the message resides in the tracheoles that attach to the MTs but is not found in the MTs themselves (17,33). In contrast, our data suggest that ...
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... (5,16,29,31,32,42). To drive fluid secretion, a proton gradient is established by a V-ATPase in principal cells. Protons move back into the cell in exchange for K /Na , and Cl moves through the stellate cells into the tubule lumen, which in turn drives water uptake (13). Because we observed DRIP expression within stellate cells of the adult MT (Figs. 3 and 4), we suggest that water moves transcellularly through DRIP. This model is consistent with the finding in Drosophila that leukokinin, which stimulates Cl transport in stellate cells, also stimulates fluid transport (31) and with the finding that slower fluid transport is observed across MTs in a Drosophila Fig. 6. DRIP-expressing ...
Citations
... These evolutionary changes also appear to relate to the movement of water. It is known for many insects that secondary cells are a major site of water flow, facilitated by expression of aquaporin water channels (2,49). By contrast, leptophragmata are considered impermeable to water; an important feature to prevent water being drawn from the haemolymph into the CNC, which would counter the CNC's ability to establish a high ionic concentration (14, 50).The ability to transport water may have been specifically lost in leptophragmata, possibly by Dachshund acquiring the ability to inhibit aquaporin gene transcription. ...
Tenebrionid beetles have been highly successful in colonising environments where water is scarce, underpinned by their unique osmoregulatory adaptations. These include a cryptonephridial arrangement of their organs, in which part of their renal/Malpighian tubules are bound to the surface of the rectum. This allows them to generate a steep osmotic gradient to draw water from within the rectum and return it to the body. Within the cryptonephridial tubules a seemingly novel cell type, the leptophragmata, is considered to play a key role in transporting potassium chloride to generate this osmotic gradient. Nothing was known about the developmental mechanisms or evolution of these unusual renal cells. Here we investigate the mechanisms underpinning development of the leptophragmata in the red flour beetle, Tribolium castaneum. We find that leptophragmata express and require a teashirt/tiptop transcription factor gene, as do the secondary renal cells of Drosophila melanogaster which lack a cryptonephridial arrangement. We also find an additional transcription factor, Dachshund, is required to establish leptophragmata identity and to distinguish them from the secondary cells in Tribolium's non-cryptonephridial region of renal tubule. Dachshund is also expressed in a sub-population of secondary cells in Drosophila. So leptophragmata, which are unique to the beetle lineage, appear to have originated from a specific renal cell type present ancestrally, and specified by a conserved repertoire of transcription factors.
... The insect aquaporin superfamily contains five main subfamilies: (1) Drosophila integral protein (Drip), (2) Pyrocoelia rufa integral protein (Prip), (3) Glyceroporin (Glp), (4) big brain (Bib), and (5) others [2]. Among them, Drip and Prip are water-selective, and they mainly transport water molecules [3][4][5]. ...
Rhyzopertha dominica Prip (RdPrip) cDNA was cloned (GenBank accession no. OK318454), and the encoded 276-amino-acid protein indicated the typical aquaporin structure, including six transmembrane regions and two NPA motifs. The developmental and tissue profiles of RdPrip transcription were determined. RdPrip was highly transcribed in female adults, followed by larvae, pupae, and male adults. The transcriptional expression levels of RdPrip were significantly high in the ovary and hindgut (including cryptonephridial systems) compared with the foregut, testis, midgut, and Malpighian tubules. Knockdown of RdPrip in female adults did not decrease fecundity, but significantly decreased the hatching rate of eggs laid by the females. The results suggest that RdPrip functions in embryonic development, not in egg formation. In addition, the transcriptional expression level of RdPrip was lower in the spinosad-resistant strain than in the susceptible one, and the resistant strain produced fewer progeny than the susceptible strain did. These studies support the functional role of RdPrip in female reproduction. The absence of significant mortality reduction in the R. dominica exposed to spinosad after RdPrip RNAi suggests that other aquaporins that were not knocked down may exist for the excretion of metabolized pesticides.
... In arthropods, for example, an alternative nomenclature system is typically used that characterizes aquaporins by their phylogeny and function (Campbell et al., 2008;Chung et al., 2012;Foguesatto et al., 2017;Lind et al., 2017;Stavang et al., 2015;Wang et al., 2022b). This nomenclature system groups aquaporins into water-selective channels similar to the Drosophila intrinsic protein, Drip (Beuron et al., 1995;Kaufmann et al., 2005;Le Cahérec et al., 1996), water and urea-transporting channels similar to the Pyrocoelia rufa integral protein, Prip (Herraiz et al., 2011), and the cell-adhesive, cation-permeating neurogenic proteins termed big brain proteins, BIB (Rao et al., 1990;Yanochko and Yool, 2002). ...
Intertidal crustaceans like Carcinus maenas shift between an osmoconforming and osmoregulating state when inhabiting full-strength seawater and dilute environments, respectively. While the bodily fluids and environment of marine osmoconformers are approximately isosmotic, osmoregulating crabs inhabiting dilute environments maintain their bodily fluid osmolality above that of their environment by actively absorbing and retaining osmolytes (e.g., Na⁺, Cl⁻, urea) while eliminating excess water. Few studies have investigated the role of aquaporins (AQPs) in the osmoregulatory organs of crustaceans, especially within brachyuran species. In the current study, three different aquaporins were identified within a transcriptome of C. maenas, including a classical AQP (CmAQP1), an aquaglyceroporin (CmGLP1), and a big-brain protein (CmBIB1), all of which are expressed in the gills and the antennal glands. Functional expression of these aquaporins confirmed water transport capabilities for CmAQP1, CmGLP1, but not for CmBIB1, while CmGLP1 also transported urea. Higher relative CmAQP1 mRNA expression within tissues of osmoconforming crabs suggests the apical/sub-apically localized channel attenuates osmotic gradients created by non-osmoregulatory processes while its downregulation in dilute media reduces the water permeability of tissues to facilitate osmoregulation. Although hemolymph urea concentrations rose upon exposure to brackish water, urea was not detected in the final urine. Due to its urea-transport capabilities, CmGLP1 is hypothesized to be involved in a urea retention mechanism believed to be involved in the production of diluted urine. Overall, these results suggest that AQPs are involved in osmoregulation and provide a basis for future mechanistic studies investigating the role of AQPs in volume regulation in crustaceans.
... No aquaammoniaporins were recovered [15,16]. Drip and Prip proteins are mainly involved in water transit [18,19], Bib is permeable to uncharged gases [20], and Eglp-only occurring in insects, such as Drip, which is permeable mostly to glycerol [21]. In crustaceans, the involvement of AQPs in osmoregulation was pointed out by their transcriptional regulation in response to salinity stress (e.g., [15,22,23]). ...
The importance of aquaporins (AQPs) in the transport of water and solutes through cell membranes is well recognized despite being relatively new. To date, despite their abundance, diversity, and presence in disparate environments, amphipods have only been mentioned in studies about the AQPs of other animals and have never been further investigated. In this work, we aimed to recover from public data available AQPs of these crustaceans and reconstruct phylogenetic affinities. We first performed BLAST searches with several queries of diverse taxa against different NCBI databases. Then, we selected the clades of AQPs retrieving the amphipod superfamily Gammaroidea as monophyletic and ran phylogenetic analyses to assess their performances. Our results show how most of the AQPs of amphipods are similar to those of other crustaceans, despite the Prip-like displayed different paralogs, and report for the first time a putative Aqp8-like for arthropods. We also found that the candidate genes of Prip-like, Bib-like, Aqp12-like, and Glp-like help solve deeper relationships in phylogenies of amphipods while leaving uncertainties in shallower parts. With our findings, we hope to increase attention to the study of amphipods as models for AQP functioning and evolution.
... The ensuing imbalance of potassium is counterbalanced by the movement of chloride through chloride channels in the SCs, which results in net movement of water from the hemolymph through aquaporin DRIP in SCs, as well as through paracellular routes. 23,24 Homeostasis is accomplished by modification of primary urine as it passes down the more proximal regions of the tubule before emptying into the hindgut via the ureters. 25 A thought-provoking aspect of MTs is their ability to evade apoptosis, unlike most of the larval tissues, during metamorphosis despite the presence of apoptotic proteins in these organs, making it all the more intriguing. ...
Background
Cells trigger caspase‐mediated apoptosis to eliminate themselves from the system when tissue needs to be sculptured, or they detect any abnormality within them, thus preventing irreparable damage to the host. However, nonapoptotic activities of caspases are also involved in many cellular functions. Interestingly, Drosophila Malpighian tubules (MTs) express apoptotic proteins, without succumbing to cell death.
Results
We show apoptosis‐independent role of executioner caspase‐3, Drice, in MT morphogenesis. Drice is required for precise cytoskeleton organization and convergent extension, failing which morphology, size, cell number, and arrangement get affected. Furthermore, characteristic stellate cell shape transformation in MTs is also governed by Drice. Genetic interaction study shows that Drice mediates its action by regulating Rho1GTPase functionally, and localization of polarity protein Disc large. Subsequently, downregulation of Rho1GTPase in Drice mutants significantly rescues the cystic MTs phenotype. The study shows a mechanism by which Drice governs tubulogenesis via Rho1GTPase‐mediated coordinated organization of actin cytoskeleton and membrane stabilization.
Conclusion
Collectively our findings suggest a nonapoptotic function of caspase‐3 in fine‐tuning of cellular rearrangement during tubule development, and these results will add to the growing understanding of diverse roles of caspases during its evolution in metazoans.
... Aquaporins (AQPs) are integral membrane proteins that transport water and, in some cases, small solutes such as urea. The Drosophila genome contains eight genes encoding aquaporins, including the Drosophila integral protein (DRIP), a highly selective water-specific channel with high sequence similarity to vertebrate AQP4 (Kaufmann et al., 2005). The integral protein PRIP is the other aquaporin we found in the analyses. ...
In healthy Drosophila melanogaster larvae, plasmatocytes and crystal cells account for 95% and 5% of the hemocytes, respectively. A third type of hemocytes, lamellocytes, are rare, but their number increases after oviposition by parasitoid wasps. The lamellocytes form successive layers around the parasitoid egg, leading to its encapsulation and melanization, and finally the death of this intruder. However, the total number of lamellocytes per larva remains quite low even after parasitoid infestation, making direct biochemical studies difficult. Here, we used the HopTum-l mutant strain that constitutively produces large numbers of lamellocytes to set up a purification method and analyzed their major proteins by 2D gel electrophoresis and their plasma membrane surface proteins by 1D SDS-PAGE after affinity purification. Mass spectrometry identified 430 proteins from 2D spots and 344 affinity-purified proteins from 1D bands, for a total of 639 unique proteins. Known lamellocyte markers such as PPO3 and the myospheroid integrin were among the components identified with specific chaperone proteins. Affinity purification detected other integrins, as well as a wide range of integrin-associated proteins involved in the formation and function of cell-cell junctions. Overall, the newly identified proteins indicate that these cells are highly adapted to the encapsulation process (recognition, motility, adhesion, signaling), but may also have several other physiological functions (such as secretion and internalization of vesicles) under different signaling pathways. These results provide the basis for further in vivo and in vitro studies of lamellocytes, including the development of new markers to identify coexisting populations and their respective origins and functions in Drosophila immunity.
... The main segment has both secretory and absorptive roles for salts and water and generates the primary urine. The PC cells of the main segment express a basolateral sodium/potassium transporter (Torrie et al., 2004), an inwardrectifier potassium transporter (Kir) (Evans et al., 2005), sodium/proton exchangers of the NHA and NHE (SLC9) families (Pullikuth et al., 2006;Rheault et al., 2007), and an aquaporin (Kaufmann et al., 2005). In contrast, the SC cells, which mostly have an absorptive role, express mainly a chloride transporter and an aquaporin (Kaufmann et al., 2005;Kolosov and O'Donnell, 2020;O'Connor and Beyenbach, 2001;O'Donnell et al., 1998). ...
... The PC cells of the main segment express a basolateral sodium/potassium transporter (Torrie et al., 2004), an inwardrectifier potassium transporter (Kir) (Evans et al., 2005), sodium/proton exchangers of the NHA and NHE (SLC9) families (Pullikuth et al., 2006;Rheault et al., 2007), and an aquaporin (Kaufmann et al., 2005). In contrast, the SC cells, which mostly have an absorptive role, express mainly a chloride transporter and an aquaporin (Kaufmann et al., 2005;Kolosov and O'Donnell, 2020;O'Connor and Beyenbach, 2001;O'Donnell et al., 1998). The expression of an SLC4 exchanger has also been reported in the SC cells of some species (Linser et al., 2012;Piermarini et al., 2010). ...
Excretion and osmoregulation are fundamental processes of the organism, as they prevent the accumulation of toxic waste products in the body and control the osmotic differences between the cells and the environment. In most animals, these phenomena take place through specialized organs, namely excretory organs, composed of diverse cell types that perform tasks such as secretion and ultrafiltration. Although the morphology and embryology of excretory organs can differ dramatically, the common spatial arrangement of structural proteins and transporters as well as the similar transcriptional developmental programs underlying their formation suggests the homology of their cell types. In this chapter, we discuss the current understanding of the evolution of excretory organs from a comparative morphological, developmental, and functional perspective, flanked by an additional, cell-type perspective. We argue that a putative homology of certain excretory cell types does not necessarily reflect the homology of the resulting organs and that integrating all different levels of comparison is crucial for addressing evolutionary questions.
... Aquaporins are present in all kingdoms of life and form a superfamily with up to six subfamilies in insects . Drosophila intrinsic protein (Drip) is a water-specific channel (Azuma et al., 2012;Kaufmann et al., 2005;Le Cahérec et al., 1996;Shakesby et al., 2009). Pyrocoelia rufa integral protein (Prip) is also a water channel (Azuma et al., 2012;Goto et al., 2011), which can also transport urea in cockroaches (Herraiz et al., 2011). ...
... Prip may also transport water in the various organs. Similar expression patterns have been reported in other insect species (Azuma et al., 2012;Kataoka et al., 2009;Kaufmann et al., 2005;Staniscuaski et al., 2013). Yi et al. (2011) detected Drip expression in the salivary gland of B. antarctica by immunohistochemistry using an anti-Drosophila melanogaster Drip antibody. ...
Larvae of the Antarctic midge Belgica antarctica Jacobs (Diptera: Chironomidae) are highly tolerant of diverse environmental stresses, including freezing, severe desiccation, and osmotic extremes. Furthermore, dehydration confers subsequent desiccation and freeze tolerance. While a role for aquaporins-channels for water and other solutes-has been proposed in these dehydration processes, the types of aquaporins involved in dehydration-driven stress tolerance remain unknown. In the present study, we investigated expression of six aquaporins (Drip, Prip, Eglp1, Eglp2, Aqp12L, and Bib) in larvae of B. antarctica subjected to under three different dehydration conditions: desiccation, cryoprotective dehydration, and osmotic dehydration. The expression of Drip and Prip was up-regulated under desiccation and cryoprotective dehydration, suggesting a role for these aquaporins in efficient water loss under these dehydration conditions. Conversely, expression of Drip and Prip was down-regulated under osmotic dehydration, suggesting that their expression is suppressed in larvae to combat dehydration. Larval water content was similarly decreased under all three dehydration conditions. Differences in responses of the aquaporins to the three forms of dehydration suggests distinct water management strategies associated with different forms of dehydration stress.
... In insects, several aquaporins have been characterized in tissues such as digestive tract (Guillam et al., 1992;Le Caherec et al., 1997;Kataoka et al., 2009aKataoka et al., , 2009bShakesby et al., 2009;Drake et al., 2010;Yin et al., 2011;Mathew et al., 2011;Souza et al., 2020), Malpighian tubules (Duchesne et al., 2003;Pietrantonio et al., 2000;Kaufmann et al., 2005;Souza et al., 2019), fat body (Spring et al., 2009;Kikawada et al., 2008;Wallace et al., 2012), and brain (Philip et al., 2011) some of which act as specific transport water channels (Campbell et al., 2008;Liu et al., 2011). Recently, five aquaporins were reported in the digestive tract and Malpighian tubules of A. mellifera (Souza et al., 2020). ...
Aquaporins are membrane proteins responsible for the rapid transport of water and solutes through the plasma membrane in almost all organisms including microorganisms, animals and plants. The knowledge about aquaporins in insects has advanced in the last years, especially in organs such as the gut and Malpighian tubules, but their roles in ovaries are poorly understood. This study reports the occurrence and the expression of gene profiles of predicted aquaporins in the ovaries of virgin and mated queens of the honeybee Apis mellifera. The expression of six aquaporin genes (Am-DRIP, Am-PRIP, Am-Eglp1, Am-Eglp2, Am-Eglp3 and Am-BIB) was investigated in the ovaries of queens of different ages and physiological status. The Am-Eglp3 has the higher level of transcript in newly emerged virgin queens. The Am-PRIP and Am-Eglp2 have a higher level of transcripts in 4 days-old virgin queens, aged expected to mate. In mated queens, only the Am-Eglp2 show high level of transcripts. Aquaporin was immunolocalized in the follicular cells of both nurse and oocytic chambers of the previtellogenic and vitellogenic follicles. This is the first report for the presence of aquaporins in the ovaries of bees.
... Our immunohistochemistry data showed a significantly reduced (P < 0.001; 2.2 fold) level of (Na + /K + )-ATPase in the MTs of HSD fed flies as compared with control ( Fig. 4H-N). Drosophila aquaporin (DRIP) is an orthologue of human aquaporin and plays role in fluid secretion (Kaufmann et al., 2005). DRIP specifically expresses in the SCs of MTs. ...
... (Na + /K + )-ATPase located on the basolateral side of the MTs balances the ratio of Na + and K + in the secreted fluid (Ianowski and O'Donnell, 2004). DRIP found in the SCs of MTs are known to regulate water balance (Kaufmann et al., 2005). Reduced level of (Na + /K + )-ATPase and DRIP suggest altered physiology of the MTs leading to impairment in the function of transporter proteins in exposed flies. ...
Continuous feeding of high dietary sugar is strongly associated with type 2 diabetes (T2D) and its secondary complications. Diabetic nephropathy (DN) is a major secondary complication that leads to glomerular and renal tubular dysfunction. The present study is aimed to investigate the effects of chronic exposure of high sugar diet (HSD) on renal tubules. Malpighian tubules (MTs), a renal organ of Drosophila, were used as a model in the study. Feeding of HSD develops T2D condition in Drosophila. The MTs showed structural abnormalities in 20 days of HSD fed flies. Impaired insulin signaling, oxidative stress, enhanced levels of AGE-RAGE and induction of apoptosis were observed in the MTs of these flies. Further, altered expression of transporters, enhanced uric acid level and reduced fluid secretion rate confirmed the impaired function of MTs in these flies. RNA-seq and RT-PCR analyses in the MTs of HSD fed-and control-flies revealed the altered expression of candidate genes that regulate several important pathways including ECM, AGE-RAGE, TGF-β, galactose, starch and sucrose metabolism that are well known mediators of renal tubular dysfunction in diabetic nephropathy (DN) patients. Disruption of insulin signaling in the MTs also causes renal tubular dysfunction similar to HSD fed flies. Overall, the study suggests that phenotypes observed in the MTs of HSD fed flies recapitulate several hallmarks of renal tubular dysfunction in DN patients. Therefore, we conclude that MTs of HSD fed flies may be used for deciphering the underlying mechanisms of T2D mediated renal tubular dysfunction.
