Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
Cortisol regulates nitric oxide synthase in freshwater and seawater acclimated rainbow trout, Oncorhynchus mykiss
Introduction
Cortisol is the major corticosteroid in fish and has a wide range of actions including ionoregulatory and metabolic functions (Mommsen et al., 1999). Interestingly, the gasotransmitter nitric oxide (NO) is also known to affect such processes (Cooper and Giulivi, 2007, Fago and Jensen, 2015, Perry et al., 2016) and it seems appropriate to expect that the two regulatory pathways may interact locally in various tissues. Whereas cortisol is a relatively slow-acting hormone, typically involved in transcriptional changes on a relatively long time scale (hours-days), NO is a gasotransmitter synthetized in various tissues that operates in seconds-minutes, characteristic of a paracrine/autocrine regulator. Even though they work on different time scales, the potential interaction between the two mediators remains to be elucidated. In salmonids, both in vivo and ex vivo studies have documented that cortisol mediates long-term osmoregulatory adjustments by stimulating branchial, renal and intestinal Na+/K+-ATPase (NKA) activity (Kiilerich et al., 2007, Kiilerich et al., 2011b, Madsen, 1990, McCormick, 2001, McCormick et al., 1991, McCormick et al., 2008, McCormick and Bern, 1989, Shrimpton and McCormick, 1999, Veillette and Young, 2005). Yet the recent discovery of NO as a rapid inhibitory modulator of ion transport and of NKA activity in fish challenges our understanding of how these regulatory processes are integrated. Evidence of NO involvement in ion transport in fish was first given by Tipsmark and Madsen (2003), who observed an inhibition of NKA activity by NO donors in gill and kidney of freshwater (FW)-acclimated brown trout. A similar inhibitory effect was subsequently reported in the gill of seawater (SW)-acclimated Atlantic salmon (Ebbesson et al., 2005). Furthermore, Evans et al. (2004) and Trischitta et al. (2007) observed a significant down-regulation of ion transport by NO in the opercular epithelium of SW-acclimated killifish and the middle intestine of SW eel, respectively. In addition, we recently showed a strong inhibition of Cl− secretion by both endogenous NO production and NO donors in the opercular membrane of SW killifish, which was primarily mediated by activation of guanylyl cyclase and cGMP signalling (Gerber et al., 2016), but suggesting S-nitrosation of ion transporting proteins as an additional mechanism. Based on these former studies in fish, it seems that cortisol and NO may have antagonistic effects on epithelial ion transport. In mammals there is evidence of such interaction. Glucocorticoids inhibit NO production in various cell and tissue types, including lung, liver, kidney, cardiac and vascular endothelial cells and macrophages (Balligand et al., 1994, Di Rosa et al., 1990, Knowles et al., 1990, Lou et al., 2001, Radomski et al., 1990, Simmons et al., 1996) by mechanisms that include inhibition of the expression and activity of nitric oxide synthases and regulation of its cofactors and substrate (Whitworth et al., 2002). Thus, some of the physiological and pharmacological effects of cortisol may be due to interactions with NO synthesis. Nitric oxide synthase (NOS) is the enzyme that catalyses the production of NO. In fish, two distinct isoforms of the enzyme have been identified: NOS1 (also called neuronal NOS, nNOS) and NOS2 (also called inducible NOS, iNOS) (Andreakis et al., 2011). The two isoforms share common domains but also present distinctive features (in structures, expression/localisation, enzymatic functions and activities) that are well-described in mammals (Alderton et al., 2001, Andrew and Mayer, 1999, Michel and Feron, 1997). In fish, the characteristics of NOS1 and NOS2 are not clearly defined. Yet, the cofactor binding domains of mammalian and teleost NOSs are well conserved (Øyan et al., 2000, Hyndman et al., 2006, Andreakis et al., 2011) suggesting some common features. For instance, the NOS1 isoform requires Ca2+ for its enzymatic activity, whereas NOS2 is Ca2+-independent and can be induced in various physiological conditions to produce NO (Nathan, 1997). Hence, the two isoforms can be activated and regulated differentially and may have distinct biological roles when expressed in different tissues.
In the present study, we hypothesized an interaction between cortisol and Nos expression in fish. First, we examined a comprehensive organ distribution of Nos1 and NOS2 in FW rainbow trout. Then, we examined the influence of cortisol, the major teleost corticosteroid (Takahashi and Sakamoto, 2013), on mRNA expression of Nos1 and Nos2 in gill, kidney and middle intestine of cortisol-treated rainbow trout acclimated to FW and SW. This study is the first to report an interaction of cortisol with NOS expression in osmoregulatory tissues of a euryhaline teleost.
Section snippets
Animals
Juvenile female rainbow trout of body mass ~ 40 g were obtained from a local fish farm (Lihme, Randbøl, Denmark). The fish were acclimated for two months to 15 °C and a 12 h:12 h light:dark cycle in aerated bio-filtered, recirculated freshwater or artificial seawater at 25 ppt (Red Sea Salts, Verneuil s/Avre, France). Fish were fed with commercial trout pellets every second day. Feeding was withheld three days prior the experiments. The experimental work followed the guidelines of the Danish Law on
Tissue distribution of Nos isoforms mRNA in FW rainbow trout
Both Nos2 and Nos1 isoforms were constitutively expressed in all organs tested. However, the mRNA level of Nos2 (Fig. 1A) and Nos1 (Fig. 1B) varied greatly among organs. Ovary and gill had relatively high levels of Nos2 mRNA, approximately 10 to 100-fold higher than in the other organs tested (Fig. 1A). The highest relative expression of Nos1 was, by far, detected in ovary followed by middle intestine and brain which was 25 to 1000-fold higher than in other organs tested (Fig. 1B).
In vivo influence of cortisol on branchial, renal and intestinal Nos mRNA expression
In FW fish,
Discussion
Cortisol, the major corticosteroid in teleosts, has a multitude of gluco- and mineralocorticoid actions (Mommsen et al., 1999, Takahashi and Sakamoto, 2013). Some of these effects relate to salinity stress, where cortisol is known to stimulate cellular proliferation and expression of specific ion-transporter genes in the gill and intestine. Less is known about such mechanisms in the kidney. NO is also a modulator of many physiological processes; its roles in vasodilation and immune function are
Acknowledgements
We thank Lene Jakobsen for technical assistance. This work was supported with grants to S.S.M. (DFF-4181-00020) and F.B.J. (10-084565) from the Danish Council for Independent Research.
References (64)
- et al.
Cytokine-inducible nitric oxide synthase (iNOS) expression in cardiac myocytes
J. Biol. Chem.
(1994) - et al.
Glucocorticoids inhibit the induction of nitric oxide synthase in macrophages
Biochem. Biophys. Res. Commun.
(1990) - et al.
Neuronal nitric oxide synthase in the gill of the killifish, Fundulus heteroclitus
Comp. Biochem. Physiol. B
(2006) - et al.
Corticosteroid regulation of Na+,K+-ATPase α1-isoforms expression in Atlantic salmon gill during smolt development
Gen. Comp. Endocrinol.
(2011) - et al.
Anti-inflammatory glucocorticoids inhibit the induction by endotoxin of nitric oxide synthase in the lung, liver and aorta of the rat
Biochem. Biophys. Res. Commun.
(1990) Effect of repetitive cortisol and thyroxine injections on chloride cell number and Na+/K+-ATPase activity in gills of freshwater acclimated rainbow trout, Salmo gairdneri
Comp. Biochem. Physiol.
(1990)- et al.
Hormonal control of salt and water balance in vertebrates
Gen. Comp. Endocrinol.
(2006) - et al.
Developmental differences in the responsiveness of gill Na+, K+-ATPase to cortisol in salmonids
Gen. Comp. Endocrinol.
(1991) - et al.
Are we missing a mineralocorticoid in teleost fish? Effects of cortisol, deoxycorticosterone and aldosterone on osmoregulation, gill Na+,K+-ATPase activity and isoform mRNA levels in Atlantic salmon
Gen. Comp. Endocrinol.
(2008) - et al.
Glucocorticoids inhibit the induction of nitric oxide synthase and the related cell damage in adenocarcinoma cells
Biochim. Biophys. Acta
(1991)
Nervous control of circulation - the role of gasotransmitters, NO, CO, and H2S
Acta Histochem.
Nitric oxide in the fish gut
Comp. Biochem. Physiol. A
Autonomic control of gut motility: a comparative view
Auton. Neurosci. Basic Clin.
Partial cloning of constitutive and inducible nitric oxide synthases and detailed neuronal expression of NOS mRNA in the cerebellum and optic tectum of adult Atlantic salmon (Salmo salar)
Mol. Brain Res.
Nitric oxide rectifies acid-base disturbance and modifies thyroid hormone activity during net confinement of air-breathing fish (Anabas testudineus Bloch)
Gen. Comp. Endocrinol.
Glucocorticoids regulate inducible nitric oxide synthase by inhibiting tetrahydrobiopterin synthesis and l-arginine transport
J. Biol. Chem.
The role of “mineralocorticoids” in teleost fish: relative importance of glucocorticoid signaling in the osmoregulation and “central” actions of mineralocorticoid receptor
Gen. Comp. Endocrinol.
Nitric oxide modulates ionic transport in the isolated intestine of the eel, Anguilla anguilla
Comp. Biochem. Physiol. A
Cortisol mediates the increase in intestinal fluid absorption in Atlantic salmon during parr-smolt transformation
Gen. Comp. Endocrinol.
Nitric oxide synthases: structure, function and inhibition
Biochem. J.
Gasotransmitters: Novel regulators of epithelial Na+ transport?
Front. Physiol.
Evolution of the nitric oxide synthase family in metazoans
Mol. Biol. Evol.
Enzymatic function of nitric oxide synthases
Cardiovasc. Res.
Nitric oxide and the immune response
Nat. Immunol.
Angiotensin and single nephron glomerular function in the trout Salmo gairdneri
Am. J. Phys.
Nitric oxide regulation of mitochondrial oxygen consumption II: molecular mechanism and tissue physiology
Am. J. Physiol. Cell Physiol.
Nitric oxide synthase in the gill of Atlantic salmon: colocalization with and inhibition of Na+,K+-ATPase
J. Exp. Biol.
Cell signaling and ion transport across the fish gill epithelium
J. Exp. Zool.
NaCl transport across the opercular epithelium of Fundulus heteroclitus is inhibited by an endothelin to NO, superoxide, and prostanoid signaling axis
Am. J. Physiol. Regul. Integr. Comp. Physiol.
Hypoxia tolerance, nitric oxide, and nitrite: lessons from extreme animals
Physiology
Regulation of renal NaCl transport by nitric oxide, endothelin, and ATP: clinical implications
Annu. Rev. Physiol.
Nitric oxide inhibition of NaCl secretion in the opercular epithelium of seawater-acclimated killifish, Fundulus heteroclitus
J. Exp. Biol.
Cited by (9)
Time-course studies of osmoregulatory responses in different salinities for the marbled eel (Anguilla marmorata)
2021, AquacultureCitation Excerpt :The values of blood osmolality are normally used as a stress indicator in fish species (Nolan et al., 1999). Cortisol, the major seawater-adapting hormone, is known to stimulate cellular proliferation and expression of specific gill transporters after binding to the glucocorticoid receptor in front of salinity changes (Breves et al., 2010b; Gerber et al., 2017). Cortisol is an important endocrine regulator of osmoregulation (Breves et al., 2014).
Myo-inositol enhances the low-salinity tolerance of turbot (Scophthalmus maximus) by modulating cortisol synthesis
2020, Biochemical and Biophysical Research CommunicationsCitation Excerpt :It also is thought to be a seawater-adapting hormone, as it promotes salt excretion in hypo-osmoregulating fish [25]. The effects of cortisol on osmoregulation have been investigated in numerous fish species [7,26,27], but the role of cortisol in the osmotic regulation of turbot is still unknown. In present study, increased plasma cortisol induced by dietary cortisol resulted in changes in osmoregulation under low salinity stress in turbot.
Molecular characterization, expression analysis of 14-3-3 beta/alpha and the effect of RNA interference on ion transporter protein Na<sup>+</sup>-K<sup>+</sup>-ATPase, Na<sup>+</sup>–H<sup>+</sup>-exchanger and CFTR in turbot (Scophthalmus maximus)
2020, Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular BiologyCitation Excerpt :Salt stress is an important factor of environmental stress in aquaculture, and osmoregulation is the main response modes of salinity stress for fish. Osmotic regulation of euryhaline fishes has been one of the research hotspots in the world, and a lot of work has been done in osmotic organ morphology, ion transport, hormone regulation, and many important results have been achieved, such as finding a number of hormone and ion transport related to salinity (Kang et al., 2010; Moorman et al., 2016; Gerber et al., 2017; Yang et al., 2017). As a relatively euryhaline species, turbot can normally survive the salinity range of 12–40 ppt, and the better growth performance can be obtained in the salinity range of 18-36 ppt (Person-Le Ruyet et al., 1991; Gaumet et al., 1995; Imsland et al., 2001; Zeng et al., 2013).
Nitric Oxide Function and Nitric Oxide Synthase Evolution in Aquatic Chordates
2023, International Journal of Molecular SciencesRedox state and metabolic responses to severe heat stress in lenok Brachymystax lenok (Salmonidae)
2023, Frontiers in Molecular Biosciences