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Peter MCS, Gayathry R, Peter VS. Inducible Nitric Oxide Synthase/Nitric Oxide System as a Biomarker for Stress and Ease Response in Fish: Implication on Na+ Homeostasis During Hypoxia. Front Physiol 2022; 13:821300. [PMID: 35655956 PMCID: PMC9152262 DOI: 10.3389/fphys.2022.821300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/06/2022] [Indexed: 11/22/2022] Open
Abstract
The cellular and organismal response to stressor-driven stimuli evokes stress response in vertebrates including fishes. Fishes have evolved varied patterns of stress response, including ionosmotic stress response, due to their sensitivity to both intrinsic and extrinsic stimuli. Fishes that experience hypoxia, a detrimental stressor that imposes systemic and cellular stress response, can evoke disturbed ion homeostasis. In addition, like other vertebrates, fishes have also developed mechanisms to recover from the impact of stress by way of shifting stress response into ease response that could reduce the magnitude of stress response with the aid of certain neuroendocrine signals. Nitric oxide (NO) has been identified as a potent molecule that attenuates the impact of ionosmotic stress response in fish, particularly during hypoxia stress. Limited information is, however, available on this important aspect of ion transport physiology that contributes to the mechanistic understanding of survival during environmental challenges. The present review, thus, discusses the role of NO in Na+ homeostasis in fish particularly in stressed conditions. Isoforms of nitric oxide synthase (NOS) are essential for the synthesis and availability of NO at the cellular level. The NOS/NO system, thus, appears as a unique molecular drive that performs both regulatory and integrative mechanisms of control within and across varied fish ionocytes. The activation of the inducible NOS (iNOS)/NO system during hypoxia stress and its action on the dynamics of Na+/K+-ATPase, an active Na+ transporter in fish ionocytes, reveal that the iNOS/NO system controls cellular and systemic Na+ transport in stressed fish. In addition, the higher sensitivity of iNOS to varied physical stressors in fishes and the ability of NO to lower the magnitude of ionosmotic stress in hypoxemic fish clearly put forth NO as an ease-promoting signal molecule in fishes. This further points to the signature role of the iNOS/NO system as a biomarker for stress and ease response in the cycle of adaptive response in fish.
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Affiliation(s)
- M. C. Subhash Peter
- Inter-University Centre for Evolutionary and Integrative Biology iCEIB, School of Life Science, University of Kerala, Kariavattom, Thiruvananthapuram, India
- Department of Zoology, University of Kerala, Kariavattom, Thiruvananthapuram, India
- *Correspondence: M. C. Subhash Peter,
| | - R. Gayathry
- Inter-University Centre for Evolutionary and Integrative Biology iCEIB, School of Life Science, University of Kerala, Kariavattom, Thiruvananthapuram, India
| | - Valsa S. Peter
- Inter-University Centre for Evolutionary and Integrative Biology iCEIB, School of Life Science, University of Kerala, Kariavattom, Thiruvananthapuram, India
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Carnevale C, Syme DA, Gamperl AK. Effects of hypoxic acclimation, muscle strain, and contraction frequency on nitric oxide-mediated myocardial performance in steelhead trout ( Oncorhynchus mykiss). Am J Physiol Regul Integr Comp Physiol 2021; 320:R588-R610. [PMID: 33501888 DOI: 10.1152/ajpregu.00014.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Whether hypoxic acclimation influences nitric oxide (NO)-mediated control of fish cardiac function is not known. Thus, we measured the function/performance of myocardial strips from normoxic- and hypoxic-acclimated (40% air saturation; ∼8 kPa O2) trout at several frequencies (20-80 contractions·min-1) and two muscle strain amplitudes (8% and 14%) when exposed to increasing concentrations of the NO donor sodium nitroprusside (SNP) (10-9 to 10-4 M). Further, we examined the influence of 1) nitric oxide synthase (NOS) produced NO [by blocking NOS with 10-4 M NG-monomethyl-l-arginine (l-NMMA)] and 2) soluble guanylyl cyclase mediated, NOS-independent, NO effects (i.e., after blockade with 10-4 M ODQ), on myocardial contractility. Hypoxic acclimation increased twitch duration by 8%-10% and decreased mass-specific net power by ∼35%. However, hypoxic acclimation only had minor impacts on the effects of SNP and the two blockers on myocardial function. The most surprising finding of the current study was the degree to which contraction frequency and strain amplitude influenced NO-mediated effects on myocardial power. For example, at 8% strain, 10-4 SNP resulted in a decrease in net power of ∼30% at 20 min-1 but an increase of ∼20% at 80 min-1, and this effect was magnified at 14% strain. This research suggests that hypoxic acclimation has only minor effects on NO-mediated myocardial contractility in salmonids, is the first to report the high frequency- and strain-dependent nature of NO effects on myocardial contractility in fishes, and supports previous work showing that NO effects on the heart (myocardium) are finely tuned spatiotemporally.
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Affiliation(s)
- Christian Carnevale
- Department of Ocean Sciences and Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Douglas A Syme
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - A Kurt Gamperl
- Department of Ocean Sciences and Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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Peter MCS, Gayathry R. Nitric oxide synthase (NOS) inhibitor L-NAME activates inducible NOS/NO system and drives multidimensional regulation of Na + /K + -ATPase in ionocyte epithelia of immersion-stressed air-breathing fish (Anabas testudineus Bloch). JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:396-416. [PMID: 33734617 DOI: 10.1002/jez.2454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 01/20/2023]
Abstract
Nitric oxide (NO) has been implicated in Na+ homeostatic control in water-breathing fishes. It is, however, uncertain whether air-breathing fish relies on NO to coordinate Na+ /K+ -ATPase (NKA)-driven Na+ transport during acute hypoxemia. We, thus, examined the action of nitric oxide synthase (NOS) inhibitor, L-NAME on NO availability, inducible NOS (iNOS) protein abundance and the regulatory dynamics of NKA in osmoregulatory epithelia of Anabas testudineus kept at induced hypoxemia. As expected in nonstressed fish, in vivo L-NAME (100 ng g-1 ) challenge for 30 min declined NO production in serum (40%) and osmoregulatory tissues (average 51.6%). Surprisingly, the magnitude of such reduction was less in hypoxemic fish after L-NAME challenge due to the net gain of NO (average 23.7%) in these tissues. Concurrently, higher iNOS protein abundance was found in branchial and intestinal epithelia of these hypoxemic fish. In nonstressed fish, L-NAME treatment inhibited the NKA activity in branchial and intestinal epithelia while stimulating its activity in renal epithelia. Interestingly in hypoxemic fish, L-NAME challenge restored the hypoxemia-inhibited NKA activity in branchial and renal epithelia. Similar recovery response was evident in the NKAα protein abundance in immunoblots and immunofluorescence images of branchial epithelia of these fish. Analysis of Nkaα1 isoform transcript abundance (Nkaα1a, α1b, α1c) also showed spatial and preferential regulation of Nkaα1 isoform switching. Collectively, the data indicate that L-NAME challenge activates iNOS/NO system in the branchial ionocyte epithelia of hypoxemia-stressed Anabas and demands multidimensional regulation of NKA to restore the Na+ transport rate probably to defend against acute hypoxemia.
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Affiliation(s)
- M C Subhash Peter
- Inter-University Centre for Evolutionary and Integrative Biology iCEIB, Thiruvananthapuram, Kerala, India.,Department of Zoology, University of Kerala, Thiruvananthapuram, Kerala, India
| | - R Gayathry
- Department of Zoology, University of Kerala, Thiruvananthapuram, Kerala, India
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Subramaniam M, Enns CB, Luu K, Weber LP, Loewen ME. Comparison of intestinal glucose flux and electrogenic current demonstrates two absorptive pathways in pig and one in Nile tilapia and rainbow trout. Am J Physiol Regul Integr Comp Physiol 2019; 318:R245-R255. [PMID: 31746628 DOI: 10.1152/ajpregu.00160.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mucosal-to-serosal flux of 14C 3-O-methyl-d-glucose was compared against the electrogenic transport of d-glucose across ex vivo intestinal segments of Nile tilapia, rainbow trout, and pig in Ussing chambers. The difference in affinities (Km "fingerprints") between pig flux and electrogenic transport of glucose, and the absence of this difference in tilapia and trout, suggest two absorptive pathways in the pig and one in the fish species examined. More specifically, the total mucosal-to-serosal flux revealed a super high-affinity, high-capacity (sHa/Hc) total glucose transport system in tilapia; a super high-affinity, low-capacity (sHa/Lc) total glucose transport system in trout and a low-affinity, low-capacity (La/Lc) total glucose transport system in pig. Comparatively, electrogenic glucose absorption revealed similar Km in both fish species, with a super high-affinity, high capacity (sHa/Hc) system in tilapia; a super high-affinity/super low-capacity (sHa/sLc) system in trout; but a different Km fingerprint in the pig, with a high-affinity, low-capacity (Ha/Lc) system. This was supported by different responses to inhibitors of sodium-dependent glucose transporters (SGLTs) and glucose transporter type 2 (GLUT2) administered on the apical side between species. More specifically, tilapia flux was inhibited by SGLT inhibitors, but not the GLUT2 inhibitor, whereas trout lacked response to inhibitors. In contrast, the pig responded to inhibition by both SGLT and GLUT2 inhibitors with a higher expression of GLUT2. Altogether, it would appear that two pathways are working together in the pig, allowing it to have continued absorption at high glucose concentrations, whereas this is not present in both tilapia and trout.
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Affiliation(s)
- Marina Subramaniam
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Cole B Enns
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Khanh Luu
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lynn P Weber
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Matthew E Loewen
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Gam LTH, Jensen FB, Huong DTT, Phuong NT, Bayley M. The effects of elevated environmental CO 2 on nitrite uptake in the air-breathing clown knifefish, Chitala ornata. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 196:124-131. [PMID: 29367072 DOI: 10.1016/j.aquatox.2018.01.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 01/09/2018] [Accepted: 01/13/2018] [Indexed: 06/07/2023]
Abstract
Nitrite and carbon dioxide are common environmental contaminants in the intensive aquaculture ponds used to farm clown knifefish (Chitala ornata) in the Mekong delta, Vietnam. Here we tested the hypothesis that hypercapnia reduces nitrite uptake across the gills, because pH regulation will reduce chloride uptake and hence nitrite uptake as the two ions compete for the same transport route via the branchial HCO3-/Cl- exchanger. Fish fitted with arterial catheters were exposed to normocapnic/normoxic water (control), nitrite (1 mM), hypercapnia (21 mmHg CO2), or combined hypercapnia (acclimated hypercapnia) and nitrite for 96 h. Blood was sampled to measure acid-base status, haemoglobin derivatives and plasma ions. Plasma nitrite increased for 48 h, but levels stayed below the exposure concentration, and subsequently decreased as a result of nitrite detoxification to nitrate. The total uptake of nitrite (evaluated as [NO2-] + [NO3-]) was significantly decreased in hypercapnia, in accordance with the hypothesis. Methemoglobin and nitrosylhemoglobin levels were similarly lower during hypercapnic compared to normocapnic nitrite exposure. The respiratory acidosis induced by hypercapnia was half-compensated by bicarbonate accumulation in 96 h, which was mainly chloride-mediated (i.e. reduced Cl- influx via the branchial HCO3-/Cl- exchanger). Plasma osmolality and main ions (Na+, Cl-) were significantly decreased by hypercapnia and by nitrite exposure, consistent with inhibition of active transport. We conclude that hypercapnia induces a long-lasting, and mainly chloride-mediated acid-base regulation that reduces the uptake of nitrite across the gills.
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Affiliation(s)
- Le Thi Hong Gam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Frank Bo Jensen
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Viet Nam
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, Building 1131 C.F. Møllers Allé 3, DK-8000 Aarhus C., Denmark.
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Marshall WS, Breves JP, Doohan EM, Tipsmark CK, Kelly SP, Robertson GN, Schulte PM. claudin-10 isoform expression and cation selectivity change with salinity in salt-secreting epithelia of Fundulusheteroclitus. ACTA ACUST UNITED AC 2018; 221:jeb.168906. [PMID: 29150449 DOI: 10.1242/jeb.168906] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/13/2017] [Indexed: 12/11/2022]
Abstract
To provide insight into claudin (Cldn) tight junction (TJ) protein contributions to branchial salt secretion in marine teleost fishes, this study examined cldn-10 TJ protein isoforms of a euryhaline teleost (mummichog; Fundulus heteroclitus) in association with salinity change and measurements of transepithelial cation selectivity. Mummichogs were transferred from freshwater (FW) to seawater (SW, 35‰) and from SW to hypersaline SW (2SW, 60‰) in a time course with transfer control groups (FW to FW, and SW to SW). FW to SW transfer increased mRNA abundance of cldn-10d and cldn-10e twofold, whilst cldn-10c and cldn-10f transcripts were unchanged. Transfer from SW to 2SW did not alter cldn-10d, and transiently altered cldn-10e abundance, but increased cldn-10c and cldn-10f fourfold. This was coincident with an increased number of single-stranded junctions (observed by transmission electron microscopy). For both salinity transfers, (1) cldn-10e mRNA was acutely responsive (i.e. after 24 h), (2) other responsive cldn-10 isoforms increased later (3-7 days), and (3) cystic fibrosis transmembrane conductance regulator (cftr) mRNA was elevated in accordance with established changes in transcellular Cl- movement. Changes in mRNA encoding cldn-10c and -10f appeared linked, consistent with the tandem repeat locus in the Fundulus genome, whereas mRNA for tandem cldn-10d and cldn-10e seemed independent of each other. Cation selectivity sequence measured by voltage and conductance responses to artificial SW revealed Eisenman sequence VII: Na+>K+>Rb+∼Cs+>Li+ Collectively, these data support the idea that Cldn-10 TJ proteins create and maintain cation-selective pore junctions in salt-secreting tissues of teleost fishes.
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Affiliation(s)
- William S Marshall
- Department of Biology, St Francis Xavier University, Antigonish, NS, Canada B2G 2W5
| | - Jason P Breves
- Department of Biology, Skidmore College, Saratoga Springs, NY 12866, USA
| | - Ellen M Doohan
- Department of Biology, St Francis Xavier University, Antigonish, NS, Canada B2G 2W5
| | - Christian K Tipsmark
- Department of Biological Sciences, University of Arkansas, Fayetteville, AK 72701, USA
| | - Scott P Kelly
- Department of Biology, York University, Toronto, ON, Canada M3J 1P3
| | - George N Robertson
- Department of Biology, St Francis Xavier University, Antigonish, NS, Canada B2G 2W5
| | - Patricia M Schulte
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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Gerber L, Jensen FB, Madsen SS. Dynamic changes in nitric oxide synthase expression are involved in seawater acclimation of rainbow trout Oncorhynchus mykiss. Am J Physiol Regul Integr Comp Physiol 2017; 314:R552-R562. [PMID: 29351430 DOI: 10.1152/ajpregu.00519.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent research has shown that nitric oxide (NO) produced by nitric oxide synthases (NOS) is an inhibitor of ion transporter activity and a modulator of epithelial ion transport in fish, but little is known on changes in the NOS/NO system during osmotic stress. We hypothesized that the NOS/NO system responds to salinity changes as an integrated part of the acclimation process. Expression and localization of nos1/Nos1 and nos2/Nos2 were investigated in gill, kidney, and intestine of freshwater (FW)- and seawater (SW)-transferred trout using quantitative PCR, Western blotting, and immunohistochemistry, along with expressional changes of major ion transporters in the gill. The classical branchial ion transporters showed expected expressional changes upon SW transfer, there among a rapid decrease in Slc26a6 mRNA, coding a branchial Cl-/[Formula: see text] exchanger. There was a major downregulation of nos1/ nos2/Nos2 expression in the gill during SW acclimation. A significant decrease in plasma nitrite supported an overall decreased Nos activity and NO production. In the middle intestine, Nos1 was upregulated during SW acclimation, whereas no changes in nos/Nos expression were observed in the posterior intestine and the kidney. Nos1 was localized along the longitudinal axis of the gill filament, beneath smooth muscle fibers of the intestine wall and in blood vessel walls of the kidney. Nos2 was localized within the epithelium adjacent to the gill filament axis and in hematopoietic tissues of the kidney. We conclude that downregulation of branchial NOS is integrated to the SW acclimation process likely to avoid the inhibitory effects of NO on active ion extrusion.
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Affiliation(s)
- Lucie Gerber
- Department of Biology, University of Southern Denmark, Odense M, Denmark
| | - Frank B Jensen
- Department of Biology, University of Southern Denmark, Odense M, Denmark
| | - Steffen S Madsen
- Department of Biology, University of Southern Denmark, Odense M, Denmark
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Gerber L, Madsen SS, Jensen FB. Cortisol regulates nitric oxide synthase in freshwater and seawater acclimated rainbow trout, Oncorhynchus mykiss. Comp Biochem Physiol A Mol Integr Physiol 2016; 204:1-8. [PMID: 27838356 DOI: 10.1016/j.cbpa.2016.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 11/02/2016] [Accepted: 11/07/2016] [Indexed: 12/16/2022]
Abstract
Cortisol and nitric oxide (NO) are regulators of ion transport and metabolic functions in fish. In the gill, they show opposite effects on Na+/K+-ATPase (NKA) activity: cortisol stimulates NKA activity while NO inhibits NKA activity. We hypothesized that cortisol may impact NO production in osmoregulatory tissues by regulating NO synthase (NOS) expression. We evaluated the influence of cortisol treatment on mRNA expression of Nos1 and Nos2 in gill, kidney and middle intestine of both freshwater (FW) and seawater (SW) acclimated rainbow trout and found both tissue- and salinity-dependent effects. Nos2 expression was down-regulated in the gill by cortisol injection in both FW and SW trout. This was substantiated by incubating gill tissue with cortisol ex vivo. Similarly, cortisol injection significantly down-regulated Nos2 expression in kidney of SW fish but not in FW fish. In the middle intestine, Nos2 expression was up-regulated by cortisol injection in FW but unchanged in SW fish. Nos1 expression was up-regulated by cortisol injection in FW kidney and down-regulated in SW kidney, whereas it was unaffected in gill and middle intestine of FW and SW fish. Our data provide the first evidence that cortisol may influence NO production in fish by regulating Nos expression. Indeed, the down-regulation of Nos2 expression by cortisol in the gill may prevent the inhibitory effect of NO on NKA activity thereby furthering the stimulatory effect of cortisol on ion-transport.
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Affiliation(s)
- Lucie Gerber
- Department of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
| | - Steffen S Madsen
- Department of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Frank B Jensen
- Department of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
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