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Na+/HCO3 cotransporter 1 (nbce1) isoform gene expression during smoltification and seawater acclimation of Atlantic salmon

Abstract

The life history of Atlantic salmon (Salmo salar) includes an initial freshwater phase (parr) that precedes a springtime migration to marine environments as smolts. The development of osmoregulatory systems that will ultimately support the survival of juveniles upon entry into marine habitats is a key aspect of smoltification. While the acquisition of seawater tolerance in all euryhaline species demands the concerted activity of specific ion pumps, transporters, and channels, the contributions of Na+/HCO3 cotransporter 1 (Nbce1) to salinity acclimation remain unresolved. Here, we investigated the branchial and intestinal expression of three Na+/HCO3 cotransporter 1 isoforms, denoted nbce1.1, -1.2a, and -1.2b. Given the proposed role of Nbce1 in supporting the absorption of environmental Na+ by ionocytes, we first hypothesized that expression of a branchial nbce1 transcript (nbce1.2a) would be attenuated in salmon undergoing smoltification and following seawater exposure. In two separate years, we observed spring increases in branchial Na+/K+-ATPase activity, Na+/K+/2Cl cotransporter 1, and cystic fibrosis transmembrane regulator 1 expression characteristic of smoltification, whereas there were no attendant changes in nbce1.2a expression. Nonetheless, branchial nbce1.2a levels were reduced in parr and smolts within 2 days of seawater exposure. In the intestine, gene transcript abundance for nbce1.1 increased from spring to summer in the anterior intestine, but not in the posterior intestine or pyloric caeca, and nbce1.1 and -1.2b expression in the intestine showed season-dependent transcriptional regulation by seawater exposure. Collectively, our data indicate that tissue-specific modulation of all three nbce1 isoforms underlies adaptive responses to seawater.

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References

  • Boeuf G (1993) Salmonid smolting: a pre-adaptation to the oceanic environment. In: Rankin JC, Jensen FB (eds) Fish ecophysiology. Chapman and Hall, London, pp 105–135

    Chapter  Google Scholar 

  • Bower NI, Li X, Taylor R, Johnston IA (2008) Switching to fast growth: the insulin-like growth factor (IGF) system in skeletal muscle of Atlantic salmon. J Exp Biol 211:3859–3870

    CAS  PubMed  Article  Google Scholar 

  • Breves JP, McCormick SD, Karlstrom RO (2014) Prolactin and teleost ionocytes: new insights into cellular and molecular targets of prolactin in vertebrate epithelia. Gen Comp Endocrinol 203:21–28

    CAS  PubMed  Article  Google Scholar 

  • Breves JP, Fujimoto CK, Phipps-Costin SK, Einarsdottir IE, Björnsson BT, McCormick SD (2017) Variation in branchial expression among insulin-like growth-factor binding proteins (igfbps) during Atlantic salmon smoltification and seawater exposure. BMC Physiol 17(1):2

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  • Chang MH, Plata C, Kurita Y, Kato A, Hirose S, Romero MF (2012) Euryhaline pufferfish NBCe1 differs from nonmarine species NBCe1 physiology. Am J Physiol Cell 302(8):C1083-1095

    CAS  Article  Google Scholar 

  • Cornell SC, Portesi DM, Veillette PA, Sundell K, Specker JL (1994) Cortisol stimulates intestinal fluid uptake in Atlantic salmon (Salmo salar) in the post-smolt stage. Fish Physiol Biochem 13:183–190

    CAS  PubMed  Article  Google Scholar 

  • Dymowska AK, Hwang PP, Goss GG (2012) Structure and function of ionocytes in the freshwater fish gill. Respir Physiol Neurobiol 18:282–292

    Article  CAS  Google Scholar 

  • Dymowska AK, Schultz AG, Blair SD, Chamot D, Goss GG (2014) Acid-sensing ion channels are involved in epithelial Na+ uptake in the rainbow trout Oncorhynchus mykiss. Am J Physiol Cell 307(3):C255–C265

    CAS  Article  Google Scholar 

  • Esbaugh AJ, Cutler B (2016) Intestinal Na+, K+, 2Cl- cotransporter 2 plays a crucial role in hyperosmotic transitions of a euryhaline teleost. Physiol Rep 4(22):e13028–e13028

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  • Evans DH, Piermarini PM, Choe KP (2005) The multifunctional fish gill: dominant site of gas exchange, osmoregulation, acid-base regulation, and excretion of nitrogenous waste. Physiol Rev 85:97–177

    CAS  PubMed  Article  Google Scholar 

  • Ferlazzo A, Carvalho ESM, Gregorio SF, Power DM, Canario AVM, Trischittla F, Fuentes J (2012) Prolactin regulates luminal bicarbonate secretion in the intestine of the sea bream (Sparus aurata L.). J Exp Biol 215:3836–3844

    CAS  PubMed  Google Scholar 

  • Fuentes J, Eddy FB (1997) Effect of manipulation of the renin-angiotensin system in control of drinking in juvenile Atlantic salmon (Salmo salar L) in fresh water and after transfer to sea water. J Comp Phys B 167(6):438–443

    CAS  Article  Google Scholar 

  • Furukawa F, Watanabe S, Inokuchi M, Kaneko T (2011) Responses of gill mitochondria-rich cells in Mozambique tilapia exposed to acidic environments (pH 4.0) in combination with different salinities. Comp Biochem Physiol A 158(4):468–476

    Article  CAS  Google Scholar 

  • Gregório SF, Carvalho ESM, Encarnação S, Wilson JM, Power DM, Canário AVM, Fuentes J (2013) Adaptation to different salinities exposes functional specialization in the intestine of the sea bream (Sparus aurata L.). J Exp Biol 216:470–479

    PubMed  Google Scholar 

  • Grosell M (2006) Intestinal anion exchange in marine fish osmoregulation. J Exp Biol 209:2813–2827

    CAS  PubMed  Article  Google Scholar 

  • Grosell M (2011) Intestinal anion exchange in marine teleosts is involved in osmoregulation and contributes to the oceanic inorganic carbon cycle. Acta Physiol 202:421–434

    CAS  Article  Google Scholar 

  • Grosell M (2014) Intestinal transport. In: Evans DH, Claiborne JB, Currie S (eds) The physiology of fishes. CRC Press, Boca Raton, pp 175–203

    Google Scholar 

  • Grosell M, Gilmour KM, Perry SF (2007) Intestinal carbonic anhydrase, bicarbonate, and proton carriers play a role in the acclimation of rainbow trout to seawater. Am J Physiol Regul Integr Comp Physiol 293(5):R2099-2111

    CAS  PubMed  Article  Google Scholar 

  • Grosell M, Genz J, Taylor JR, Perry SF, Gilmour KM (2009) The involvement of H+-ATPase and carbonic anhydrase in intestinal HCO3 secretion in seawater-acclimated rainbow trout. J Exp Biol 212:1940–1948

    CAS  PubMed  Article  Google Scholar 

  • Guh Y, Lin C, Hwang PP (2015) Osmoregulation in zebrafish: ion transport mechanisms and functional regulation. EXCLI J 14:627–659

    PubMed  PubMed Central  Google Scholar 

  • Hirano T, Mayer-Gostan N (1976) Eel esophagus as an osmoregulatory organ. Proc Nat Acad Sci USA 73:1348–1350

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  • Hirano T, Utida S (1968) Effects of ACTH and cortisol on water movement in isolated intestine of the eel, Anguilla Japonica. Gen Comp Endocrinol 11(2):373–380

    CAS  PubMed  Article  Google Scholar 

  • Hirano T, Prunet P, Kawauchi H, Takahashi A, Ogasawara T, Kubota J, Nishioka RS, Bern HA, Takada K, Ishii S (1985) Development and validation of a salmon prolactin radioimmunoassay. Gen Comp Endocrinol 59(2):266–276

    CAS  PubMed  Article  Google Scholar 

  • Hiroi J, McCormick SD (2012) New insights into gill ionocyte and ion transporter function in euryhaline and diadromous fish. Resp Physiol Neurobiol 184:257–268

    CAS  Article  Google Scholar 

  • Hoar WS (1988) The physiology of smolting salmonids. In: Hoar WS, Randall DJ (eds) Fish physiology, vol XIB. Academic Press, New York, pp 275–343

    Google Scholar 

  • Kiilerich P, Kristiansen K, Madsen SS (2007) Cortisol regulation of ion transporter mRNA in Atlantic salmon gill and the effect of salinity on the signaling pathway. J Endocrinol 194:417–427

    CAS  PubMed  Article  Google Scholar 

  • Kurita Y, Nakada T, Kato A, Doi H, Mistry AC, Chang MH, Romero MF, Hirose S (2008) Identification of intestinal bicarbonate transporters involved in formation of carbonate precipitates to stimulate water absorption in marine teleost fish. Am J Physiol Regul Integr Comp Physiol 294(4):R1402–R1412

    CAS  PubMed  Article  Google Scholar 

  • Lee YC, Yan JJ, Cruz SA, Horng JL, Hwang PP (2011) Anion exchanger 1b, but not sodium-bicarbonate cotransporter 1b, plays a role in transport functions of zebrafish H+-ATPase-rich cells. Am J Physiol Cell 300(2):C295-307

    CAS  Article  Google Scholar 

  • Leguen I, Le Cam A, Montfort J, Peron S, Fautrel A (2015) Transcriptomic analysis of trout gill ionocytes in fresh water and sea water using laser capture microdissection combined with microarray analysis. PLoS ONE 10(10):e0139938

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  • Lema SC, Carvalho PG, Egelston JN, Kelly JT, McCormick SD (2018) Dynamics of gene expression responses for ion transport proteins and aquaporins in the gill of a euryhaline pupfish during freshwater and high-salinity acclimation. Physiol Biochem Zool 91(6):1148–1171

    PubMed  Article  Google Scholar 

  • Li Z, Lui EY, Wilson JM, Ip YK, Lin Q, Lam TJ, Lam SH (2014) Expression of key ion transporters in the gill and esophageal-gastrointestinal tract of euryhaline Mozambique tilapia Oreochromis mossambicus acclimated to fresh water, seawater and hypersaline water. PLoS ONE 9(1):e87591

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  • Mackie PM, Gharbi K, Ballantyne JS, McCormick SD, Wright PA (2007) Na+/K+/2Cl cotransporter and CFTR gill expression after seawater transfer in smolts (0+) of different Atlantic salmon (Salmo salar) families. Aquaculture 272:625–635

    CAS  Article  Google Scholar 

  • Madsen SS, Engelund MB, Cutler CP (2015) Water transport and functional dynamics of aquaporins in osmoregulatory organs of fishes. Biol Bull 229(1):70–92

    CAS  PubMed  Article  Google Scholar 

  • Marshall WS, Grosell M (2006) Ion transport, osmoregulation and acid-base balance. In: Evans DH, Claiborne JB (eds) The physiology of fishes. CRC Press, Boca Raton, pp 177–230

    Google Scholar 

  • Marshall WS, Howard JA, Cozzi RR, Lynch EM (2002) NaCl and fluid secretion by the intestine of the teleost Fundulus heteroclitus: involvement of CFTR. J Exp Biol 205:745–758

    CAS  PubMed  Article  Google Scholar 

  • McCormick SD (1993) Methods for nonlethal gill biopsy and measurement of Na+, K+,-ATPase activity. Can J Fish Aquat Sci 50:656–658

    CAS  Article  Google Scholar 

  • McCormick SD, Shrimpton JM, Carey JB, O’Dea MF, Sloan KE, Moriyama S, Björnsson BT (1998) Repeated acute stress reduces growth rate of Atlantic salmon parr and alters plasma growth hormone, insulin-like growth factor I and cortisol. Aquaculture 168:221–235

    CAS  Article  Google Scholar 

  • McCormick SD, Shrimpton JM, Moriyama S, Björnsson BT (2007) Differential hormonal responses of Atlantic salmon parr and smolt to increased daylength: a possible developmental basis for smolting. Aquaculture 273:337–344

    CAS  Article  Google Scholar 

  • McCormick SD, Regish AM, Christensen AK (2009) Distinct freshwater and seawater isoforms of Na+/K+-ATPase in gill chloride cells of Atlantic salmon. J Exp Biol 212:3994–4001

    CAS  PubMed  Article  Google Scholar 

  • McCormick SD, Regish AM, Christensen AK, Björnsson BT (2013) Differential regulation of sodium-potassium pump isoforms during smolt development and seawater exposure of Atlantic salmon. J Exp Biol 216:1142–1151

    CAS  PubMed  Article  Google Scholar 

  • Nichols DJ, Weisbart M (1985) Cortisol dynamics during seawater adaptation of Atlantic salmon Salmo salar. Am J Physiol 248(6 Pt 2):R651-659

    CAS  PubMed  Google Scholar 

  • Nielsen C, Madsen SS, Björnsson BT (1999) Changes in branchial and intestinal osmoregulatory mechanisms and growth hormone levels during smolting in hatchery-reared and wild brown trout. J Fish Biol 54:799–818

    CAS  Article  Google Scholar 

  • Nilsen TO, Ebbesson LOE, Madsen SS, McCormick SD, Andersson E, Björnsson BT, Prunet P, Stefansson SO (2007) Differential expression of gill Na+/K+-ATPase α- and β-subunits, Na+/K+/2Cl cotransporter and CFTR anion channel in juvenile anadromous and landlocked Atlantic salmon Salmo salar. J Exp Biol 210:2885–2896

    CAS  PubMed  Article  Google Scholar 

  • Parks SK, Tresguerres M, Goss GG (2007) Interactions between Na+ channels and Na+-HCO3 cotransporters in the freshwater fish gill MR cell: a model for transepithelial Na+ uptake. Am J Physiol Cell 292(2):C935-944

    CAS  Article  Google Scholar 

  • Pelis RM, McCormick SD (2001) Effects of growth hormone and cortisol on Na+-K+-2Cl cotransporter localization and abundance in the gills of Atlantic salmon. Gen Comp Endocrinol 124:134–143

    CAS  PubMed  Article  Google Scholar 

  • Perry SF, Gilmour KM (2006) Acid-base and CO2 excretion in fish: unanswered questions and emerging models. Resp Physiol Neurobiol 154:199–215

    CAS  Article  Google Scholar 

  • Pfaffl MW (2001) A new mathematical model for relative quantification in real-time RT-PCR. Nucl Acids Res 29(9):e45

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  • Ruhr IM, Takei Y, Grosell M (2016) The role of the rectum in osmoregulation and the potential effect of renoguanylin on SLC26a6 transport activity in the Gulf toadfish (Opsanus beta). Am J Physiol Regul Integr Comp Physiol 311:R179-191

    PubMed  PubMed Central  Article  Google Scholar 

  • Sattin G, Mager EM, Beltramini M, Grosell M (2010) Cytosolic carbonic anhydrase in the Gulf toadfish is important for tolerance to hypersalinity. Comp Biochem Physiol A 156(2):169–175

    CAS  Article  Google Scholar 

  • Schultz ET, McCormick SD (2013) Euryhalinity in an evolutionary context. In: McCormick SD, Farrell AP, Brauner CJ (eds) Euryhaline fishes. Elsevier, New York, pp 477–529

    Google Scholar 

  • Shaughnessy CA, Breves JP (2021) Molecular mechanisms of Cl transport in fishes: new insights and their evolutionary context. J Exp Zool A 335(2):207–216

    CAS  Article  Google Scholar 

  • Sundell K, Sundh H (2012) Intestinal fluid absorption in anadromous salmonids: importance of tight junctions and aquaporins. Front Physiol 3:338

    Article  CAS  Google Scholar 

  • Sundell K, Jutfelt E, Agustsson T, Olsen RE, Sandblom E, Hansen T (2003) Intestinal transport mechanisms and plasma cortisol levels during normal and out-of-season parr-smolt transformation of Atlantic salmon, Salmo salar. Aquaculture 222:265–285

    CAS  Article  Google Scholar 

  • Sundh H, Nilsen TO, Lindström J, Hasselberg-Frank L, Stefansson SO, McCormick SD, Sundell K (2014) Development of intestinal ion-transporting mechanisms during smoltification and seawater acclimation in Atlantic salmon Salmo salar. J Fish Biol 85:1227–1252

    CAS  PubMed  Article  Google Scholar 

  • Takei Y (2021) The digestive tract as an essential organ for water acquisition in marine teleosts: lessons from euryhaline eels. Zool Lett 7(1):10

    Article  Google Scholar 

  • Takei Y, Hiroi J, Takahashi H, Sakamoto T (2014) Diverse mechanisms for body fluid regulation in teleost fishes. Am J Physiol Regul Integr Comp Physiol 307:R778-792

    CAS  PubMed  Article  Google Scholar 

  • Takei Y, Wong MK, Pipil S, Ozaki H, Suzuki Y, Iwasaki W, Kusakabe M (2017) Molecular mechanisms underlying active desalination and low water permeability in the esophagus of eels acclimated to seawater. Am J Physiol Regul Integr Comp Physiol 312(2):R231-244

    PubMed  Article  Google Scholar 

  • Taylor JR, Mager EM, Grosell M (2010) Basolateral NBCe1 plays a rate-limiting role in transepithelial intestinal HCO3 secretion, contributing to marine fish osmoregulation. J Exp Biol 213(3):459–468

    CAS  PubMed  Article  Google Scholar 

  • Tipsmark CK, Madsen SS, Seidelin M, Christensen AS, Cutler CP, Cramb G (2002) Dynamics of 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

    CAS  PubMed  Article  Google Scholar 

  • Tse WK, Chow SC, Lai KP, Au DW, Wong CK (2011) Modulation of ion transporter expression in gill mitochondrion-rich cells of eels acclimated to low-Na+ or -Cl freshwater. J Exp Zool A 315(7):385–393

    CAS  Article  Google Scholar 

  • Utida S, Hirano T, Oide H, Ando M, Johnson DW, Bern HA (1972) Hormonal control of the intestine and urinary bladder in teleost osmoregulation. Gen Comp Endocrinol 3(Suppl):317–327

    Article  Google Scholar 

  • Veillette PA, White RJ, Specker JL (1993) Changes in intestinal fluid transport in Atlantic salmon (Salmo salar L.) during parr-smolt transformation. Fish Physiol Biochem 12(3):193–202

    CAS  PubMed  Article  Google Scholar 

  • Veillette PA, Sundell K, Specker JL (1995) Cortisol mediates the increase in intestinal fluid absorption in Atlantic salmon during parr-smolt transformation. Gen Comp Endocrinol 97:250–258

    CAS  PubMed  Article  Google Scholar 

  • Veillette PA, White RJ, Specker JL, Young G (2005) Osmoregulatory physiology of pyloric ceca: regulated and adaptive changes in chinook salmon. J Exp Zool A 303(7):608–613

    Article  Google Scholar 

  • Watanabe S, Mekuchi M, Ideuchi H, Kim YK, Kaneko T (2011) Electroneutral cation-Cl cotransporters NKCC2β and NCCβ expressed in the intestinal tract of Japanese eel Anguilla japonica. Comp Biochem Physiol A 159:427–435

    Article  CAS  Google Scholar 

  • Wong MK, Pipil S, Kato A, Takei Y (2016) Duplicated CFTR isoforms in eels diverged in regulatory structures and osmoregulatory functions. Comp Biochem Physiol A 199:130–141

    CAS  Article  Google Scholar 

  • Zhang K, Zhang X, Wen H, Qi X, Fan H, Tian Y, Liu Y, Li Y (2019) Spotted sea bass (Lateolabrax maculatus) cftr, nkcc1a, nkcc1b, and nkcc2: genome-wide identification, characterization and expression analysis under salinity stress. J Ocean Univ China 18:1470–1480

    CAS  Article  Google Scholar 

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Acknowledgements

We appreciate the excellent laboratory assistance and fish care provided by Amy Regish and Dan Hall during the course of this study.

Funding

This work was supported by the National Science Foundation (IOS-1755131 to JPB). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government.

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Correspondence to Jason P. Breves.

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All experiments were conducted in accordance with U.S. Geological Survey institutional guidelines and an approved IACUC review (LSC-9070).

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Breves, J.P., McKay, I.S., Koltenyuk, V. et al. Na+/HCO3 cotransporter 1 (nbce1) isoform gene expression during smoltification and seawater acclimation of Atlantic salmon. J Comp Physiol B 192, 577–592 (2022). https://doi.org/10.1007/s00360-022-01443-8

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Keywords

  • Gill
  • Intestine
  • Ionocyte
  • Parr
  • Pyloric caeca
  • Smolts