Role of glucocorticoid receptor in acclimation of killifish (<i>Fundulus heteroclitus</i>) to seawater and effects of arsenic

Shaw, Joseph R.; Gabor, Kristen; Lankowski, Alexander; Durant, Lydia; Thibodeau, Renee; Stanton, Caitlin R.; Barnaby, Roxanna; Coutermarsh, Bonita; Karlson, Katherine H.; Sato, Junji; Hamilton, Joshua W.

doi:10.1152/ajpregu.00328.2006

Cited by 59 publications

(87 citation statements)

References 47 publications

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“…Despite these observations, the administration of either aldosterone or deoxycorticosterone in Atlantic salmon parr did not significantly alter the response of fish to a 24h seawater challenge (McCormick et al, 2008), and this lack of response is in agreement with a small number of additional studies that have similarly reported an absence of effect when considering a role for either aldosterone or deoxycorticosterone in salt and water balance in fish (Chan et al, 1967;Takahashi et al, 2006;Umminger and Gist, 1973). Nevertheless, studies have reported that the MR antagonist spironolactone can alter endpoints of osmoregulation in fish and that the effects of spironolactone can differ from the effects of the GR antagonist RU486 (Kiilerich et al, 2007;Scott et al, 2005;Shaw et al, 2007;Sloman et al, 2001).…”

Section: Introductionsupporting

confidence: 79%

Glucocorticoid and mineralocorticoid receptors regulate paracellular permeability in a primary cultured gill epithelium

Kelly

Chasiotis

2011

Journal of Experimental Biology

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SUMMARYThe role of corticosteroid receptors (CRs) in the regulation of gill permeability was examined using a primary cultured trout gill epithelium. The epithelium expressed both glucocorticoid receptors (GR1 and GR2) and a mineralocorticoid receptor (MR), and cortisol treatment significantly increased transepithelial resistance (TER) and decreased paracellular [ 3 H]PEG-4000 flux. Epithelial permeability was unaffected by deoxycorticosterone or aldosterone. The GR antagonist RU486 as well as MR antagonists spironolactone and RU26752 significantly reduced, but did not completely block, the effects of cortisol. The MR antagonist eplerenone was without effect. Only RU486 + spironolactone or RU486 + RU26752 treatment completely suppressed the effects of cortisol. On its own, RU486 had cortisol-like effects which could be blocked by spironolactone, suggesting that although RU486 is a GR antagonist, in this system it may also have agonistic properties that are mediated through the MR. The GR agonist dexamethasone increased TER and reduced [ 3 H]PEG-4000 flux across cultured epithelia and was unaffected by MR antagonists. Therefore, alterations in transcript abundance of select tight junction (TJ) proteins were examined in response to cortisol, dexamethasone (a GR agonist) and RU486 (as a MR agonist). Occludin and claudin-7, -8d, -12 and -31 mRNA were significantly elevated in response to cortisol, dexamethasone or RU486 treatment. Claudin-3a mRNA was significantly elevated in response to cortisol or dexamethasone only, and claudin-28b and -30 mRNA were significantly altered following cortisol or RU486 treatment only. The data support a role for the GRs and MR in regulating gill permeability and suggest that TJ proteins are responsive to cortisol through both or individual CR types.

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Section: Introductionsupporting

confidence: 79%

Glucocorticoid and mineralocorticoid receptors regulate paracellular permeability in a primary cultured gill epithelium

Kelly

Chasiotis

2011

Journal of Experimental Biology

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“…We found the CFTR signal almost exclusively in seawater-acclimated alewives. Similarly, higher acclimation salinity stimulated increased branchial CFTR transcript abundance in killifish (Singer et al, 1998) and Atlantic salmon [CFTRI (Singer et al, 2002;Nilsen et al, 2007)] and CFTR protein expression in killifish (Shaw et al, 2007) and sea bass (Bodinier et al, 2009). We conclude that CFTR functions in Cl -secretion in hypo-osmoregulating alewives.…”

Section: Discussionsupporting

confidence: 55%

Branchial ionocyte organization and ion-transport protein expression in juvenile alewives acclimated to freshwater or seawater

Christensen

Hiroi

Schultz

et al. 2012

Journal of Experimental Biology

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SUMMARYThe alewife (Alosa pseudoharengus) is a clupeid that undergoes larval and juvenile development in freshwater preceding marine habitation. The purpose of this study was to investigate osmoregulatory mechanisms in alewives that permit homeostasis in different salinities. -cotransporter (NKCC1) were greater in seawater-acclimated individuals by 40% and 200%, respectively. NKA and NKCC1 were localized on the basolateral surface and tubular network of ionocytes in both acclimation groups. Immunohistochemical labeling for the cystic fibrosis transmembrane conductance regulator (CFTR) was restricted to the apical crypt of ionocytes in seawater-acclimated individuals, whereas sodium/hydrogen exchanger 3 (NHE3) labeling was present on the apical surface of ionocytes in both acclimation groups. Ionocytes were concentrated on the trailing edge of the gill filament, evenly distributed along the proximal 75% of the filamental axis and reduced distally. Ionocyte size and number on the gill filament were not affected by salinity; however, the number of lamellar ionocytes was significantly lower in seawater-acclimated fish. Confocal z-series reconstructions revealed that mature ionocytes in seawater-acclimated alewives occurred in multicellular complexes. These complexes might reduce paracellular Na + resistance, hence facilitating Na + extrusion in hypo-osmoregulating juvenile alewives after seaward migration.

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“…The effect of cortisol on CFTR-I and CFTR-II levels in FWand SW gills was consistently abolished by RU486, indicating that cortisol signals through the GR in both hyper-and hypo-osmoregulating gill tissue. An inhibitory effect of RU486 was also shown for CFTR in the gill of SW-acclimating (Shaw et al 2007), but not FW-acclimating (Scott et al 2005) killifish. The present reduction of CFTR levels by RU486 alone when compared with control levels may be due to blocking of endogenous cortisol left in the tissue or due to a nonspecific effect of the antagonist.…”

Section: Regulation Of Cftr-i and Cftr-iimentioning

confidence: 84%

“…These antagonists have previously been employed in several fish studies (Sloman et al 2001, Bury et al 2003, Scott et al 2005, Shaw et al 2007) without appreciably unspecific effects. However, the limited use and the insufficient validation of specificity of the antagonists in fish systems might impute some uncertainty to the conclusions.…”

Section: Fig 5b) No Significant Effect Of Cortisol or Antagonists On Hmentioning

confidence: 99%

Cortisol regulation of ion transporter mRNA in Atlantic salmon gill and the effect of salinity on the signaling pathway

Kiilerich¹,

Kristiansen²,

Madsen³

2007

Journal of Endocrinology

113

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Role of glucocorticoid receptor in acclimation of killifish (Fundulus heteroclitus) to seawater and effects of arsenic

Abstract: Role of glucocorticoid receptor in acclimation of killifish (Fundulus heteroclitus) to seawater and effects of arsenic.

Cited by 59 publications

References 47 publications

Glucocorticoid and mineralocorticoid receptors regulate paracellular permeability in a primary cultured gill epithelium

Glucocorticoid and mineralocorticoid receptors regulate paracellular permeability in a primary cultured gill epithelium

Branchial ionocyte organization and ion-transport protein expression in juvenile alewives acclimated to freshwater or seawater

Cortisol regulation of ion transporter mRNA in Atlantic salmon gill and the effect of salinity on the signaling pathway

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