Abstract
Most vertebrate nephrons possess an inherited ability to secrete fluid in normal or pathophysiological states. We hypothesized that renal aquaporin expression and localization are functionally regulated in response to seawater and during smoltification in Atlantic salmon and thus reflect a shift in renal function from filtration towards secretion. We localized aquaporins (Aqp) in Atlantic salmon renal tubular segments by immunohistochemistry and monitored their expressional dynamics using RT-PCR and immunoblotting. Three aquaporins: Aqpa1aa, Aqp1ab and Aqp8b and two aquaglyceroporins Aqp3a and Aqp10b were localized in the kidney of salmon. The staining for all aquaporins was most abundant in the proximal kidney tubules and there was no clear effect of salinity or developmental stage on localization pattern. Aqp1aa and Aqp3a were abundant apically but extended throughout the epithelial cells. Aqp10b was expressed apically and along the lateral membrane. Aqp8b was mainly basolateral and Aqp1ab was located in sub-apical intracellular compartments. mRNAs of aqp8b and aqp10b were higher in FW smolts compared to FW parr, whereas the opposite was true for aqp1aa. Aqp mRNA levels changed in response to both SW and sham transfer. Protein levels, however, were stable for most paralogs. In conclusion, aquaporins are abundant in salmon proximal renal tubules and may participate in water secretion and thus urine modification as suggested for other vertebrates. Further studies should seek to couple functional measurements of single nephrons to expression and localization of Aqps in the salmonid kidney.
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Akabane G, Ogushi Y, Hasegawa T, Suzuki M, Tanaka S (2007) Gene cloning and expression of an aquaporin (AQP-h3BL) in the basolateral membrane of water permeable epithelial cells in osmoregulatory organs of the tree frog. Am J Physiol Regul Integr Comp Physiol 292:R2340–R2351
Althoff T, Hentschel H, Luig J, Schütz H, Kasch M, Kinne RKH (2007) Na+-d-glucose cotransporter in the kidney of Leucoraja erinacea: molecular identification and intrarenal distribution. Am J Physiol Regul Integr Comp Physiol 292:R2391–R2399
Amer S, Brown JA (1995) Glomerular actions of arginine vasotocin in the in situ perfused trout kidney. Am J Physiol Regul Integr Comp Physiol 269:R775–R780
Anderson BG, Loewen RD (1975) Renal morphology of freshwater trout. Am J Anat 143:93–114
Babonis LS, Miller SN, Evans DH (2011) Renal responses to salinity change in snakes with and without salt glands. J Exp Biol 214:2140–2156
Beyenbach K (2004) Kidneys sans glomeruli. Am J Physiol Renal Physiol 286:F811–F827
Brown JA, Jackson BA, Oliver JA, Henderson IW (1978) Single nephron filtration rates (SNGFR) in the trout, Salmo gairdneri. Pflügers Arch 377:101–108
Cerdà J, Finn RN (2010) Piscine aquaporins: an overview of recent advances. J Exp Zool 313A:1–28
Cerdà J, Zapater C, Chauvigné F, Finn RN (2013) Water homeostasis in the fish oocyte: new insights into the role and molecular regulation of a teleost-specific aquaporin. Fish Physiol Biochem 39:19–27
Cliff WH, Beyenbach KW (1992) Secretory renal proximal tubules in seawater- and freshwater-adapted killifish. Am J Physiol Renal Physiol 262:F108–F116
Cutler CP, Martinez AS, Cramb G (2007) The role of aquaporin 3 in teleost fish. Comp Biochem Physiol 148A:82–91
Dantzler WH (2005) Challenges and intriguing problems in comparative renal physiology. J Exp Biol 208:587–594
Elkjær ML, Nejsum LN, Grecz V, Kwon TH, Jensen UB, Frøkiær J, Nielsen S (2001) Immunolocalization of aquaporin-8 in rat kidney, gastrointestinal tract, testis and airways. Am J Physiol Renal Physiol 281:F1047–F1057
Engelund MB, Madsen SS (2011) The role of aquaporins in the kidney of euryhaline teleosts. Front Physiol 2:51. doi:10.3389/fphys.2011.00051
Engelund MB, Chauvigné F, Christensen BM, Finn RN, Cerdà J, Madsen SS (2013) Differential expression and novel permeability properties of three aquaporin 8 paralogs from seawater-challenged Atlantic salmon smolts. J Exp Biol 216:3873–3885
García F, Kierbel A, Larocca MC, Gradilone SA, Splinter P, LaRusso NF, Marinelli RA (2001) The water channel aquaporin-8 is mainly intracellular in rat hepatocytes, and its plasma membrane insertion is stimulated by cyclic AMP. J Biol Chem 276(15):12147–12152
Giffard-Mena I, Boulo V, Aujoulat F, Fowden H, Castille R, Charmantier G, Cramb G (2007) Aquaporin molecular characterization in the sea-bass (Dicentrarchus labrax): the effect of salinity on AQP1 and AQP3 expression. Comp Biochem Physiol A148:430–444
Grantham JJ, Wallace DP (2002) Return of the secretory kidney. Am J Physiol Renal Physiol 282:F2–F9
Hickman CP Jr, Trump BF (1969) The kidney. In: Hoar WS, Randall DJ (eds) Fish physiology, vol 1. Academic Press, New York, pp 91–239
Kato A, Muro T, Kimura Y, Li S, Islam Z, Ogoshi M, Doi H, Hirose S (2011) Differential expression of Na+-Cl− cotransporter and Na+-K+-Cl− cotransporter 2 in the distal nephrons of euryhaline and seawater pufferfishes. Am J Physiol Regul Integr Comp Physiol 300:R284–R297
Katoh F, Cozzi RRF, Marshall WS, Goss GG (2008) Distinct Na+/K+/2Cl− cotransporter localization in kidneys and gills of two euryhaline species, rainbow trout and killifish. Cell Tissue Research 334:265–281
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:265–275
Madsen SS, Olesen, JH, Bedal K, Engelund MB, Velasco-Santamaría YM, Tipsmark CK (2011) Functional characterization of water transport and cellular localization of three aquaporin paralogs in the salmonid intestine. Front Physiol 2:56. doi:10.3389/fphys.2011.00056
Martinez AS, Cutler CP, Wilson GD, Phillips C, Hazon N, Cramb G (2005) Cloning and expression of three aquaporin homologues from the European eel (Anguilla anguilla): effects of seawater acclimation and cortisol treatment on renal expression. Biol Cell 97:615–627
Nakada T, Zandi-Nejad K, Kurita Y, Kudo H, Broumand V, Kwon CY, Mercado A, Mount DB, Hirose S (2005) Roles of Slc13a1 and Slc26a1 sulfate transporters of eel kidney in sulphate homeostasis and osmoregulation in freshwater. Am J Physiol Regul Integr Comp Physiol 289:R575–R585
Nielsen S, Frøkiær J, Marples D, Kwon T, Agre P, Knepper MA (2002) Aquaporins in the kidney: from molecules to medicine. Physiol Rev 82:205–244
Nishimura H, Yang Y (2013) Aquaporins in avian kidneys: function and perspectives. Am J Physiol Regul Integr Comp Physiol 305:R1201–R1214
Olsvik PÅ, Lie KK, Jordal AO, Nilsen TO, Hordvik I (2005) Evaluation of potential reference genes in real-time RT-PCR studies of Atlantic salmon. BMC Mol Bio 6:21
Pandey RN, Yaganti S, Coffey S, Frisbie J, Alnajjar K, Goldstein D (2010) Expression and immunolocalization of aquaporins HC-1, -2, and -3 in Cope’s gray treefrog, Hyla chrysoscelis. Comp Biochem Physiol A157:86–94
Pfaffl MW (2001) A new mathematical model for relative quantification in real-time RT-PCR. Nucleic Acids Res 29:e45
Pisitkun T, Hoffert JD, Saeed F, Knepper MA (2012) NHLBI-AbDesigner: an online tool for design of peptide-directed antibodies. Am J Physiol Cell Physiol 302:C154–C164
Preston GM, Carroll TP, Guggino WB, Agre P (1992) Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein. Science 256:385–387
Santos CR, Estêvão MD, Fuentes J, Cardoso JC, Fabra M, Passos AL, Detmers FJ, Deen PM, Cerdà J, Power DM (2004) Isolation of a novel aquaglyceroporin from a marine teleost (Sparus auratus): function and tissue distribution. J Exp Biol 207:1217–1227
Schmidt-Nielsen B, Renfro JL (1975) Kidney function of the American eel Anguilla rostrata. Am J Physiol 228(2):420–431
Schnermann J, Huang Y, Mizel D (2013) Fluid reabsorption in proximal convoluted tubules of mice with gene deletions of claudin-2 and/or aquaporin1. Am J Physiol Renal Physiol 305:F1352–F1364
Teranishi K, Kaneko T (2010) Spatial, cellular, and intracellular localization of Na+/K+-ATPase in the sterically disposed renal tubules of Japanese Eel. J Histochem Cytochem 58(8):707–719
Tingaud-Sequeira A, Calusinska M, Finn RN, Chauvigne F, Lozano J, Cerdà J (2010) The zebrafish genome encodes the largest vertebrate repertoire of functional aquaporins with dual paralogy and substrate specificities similar to mammals. BMC Evol Biol 10:38
Tipsmark CK, Madsen SS, Seidelin M, Christensen AS, Cutler CP, Cramb G (2002) Dynamics of a Na+, K+, 2Cl− cotransporter and Na+, K+-ATPase expression in the branchial epithelium of brown trout (Salmo trutta) and Atlantic Salmon (Salmo salar). J Exp Zool 293:106–118
Tipsmark CK, Sørensen KJ, Madsen SS (2010) Aquaporin expression dynamics in osmoregulatory tissues of Atlantic salmon during smoltification and seawater acclimation. J Exp Biol 213:368–379
Watanabe T, Takei Y (2011) Molecular physiology and functional morphology of SO4 2− excretion by the kidney of seawater-adapted eels. J Exp Biol 214:1783–1790
Watanabe S, Kaneko T, Aida K (2005) Aquaporin-3 expressed in the basolateral membrane of gill chloride cells in Mozambique tilapia Oreochromis mossambicus adapted to freshwater and seawater. J Exp Biol 208:2673–2682
Xue Y, Ren J, Gao X, Jin C, Wen L, Yao X (2008) GPS 2.0, a tool to predict kinase-specific phosphorylation sites in hierarchy. Mol Cell Proteomics 7(9):1598–1608
Acknowledgments
The staff at the Danish Centre for Wild Salmon is thanked for their help with animal husbandry and seawater challenge experiments. Annette Duus is thanked for valuable technical assistance. The study was supported by a grant from the Danish Natural Research council to Steffen S. Madsen (09-070689).
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The authors declare that there are no competing interests.
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Communicated by G. Heldmaier.
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Engelund, M.B., Madsen, S.S. Tubular localization and expressional dynamics of aquaporins in the kidney of seawater-challenged Atlantic salmon. J Comp Physiol B 185, 207–223 (2015). https://doi.org/10.1007/s00360-014-0878-0
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DOI: https://doi.org/10.1007/s00360-014-0878-0