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Nitric Oxide Enhances NFATc‐mediated Aquaporin‐2 Expression
Author(s) -
Gonzalez Bosc Laura V,
Frutos Sergio,
Kanagy Nancy L,
Majowicz Mónica P,
Vidal Norberto A,
Albertoni Borghese María F
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.495.20
Subject(s) - activator (genetics) , calcineurin , ionomycin , nfat , transfection , chemistry , nitric oxide , aquaporin 2 , reporter gene , microbiology and biotechnology , luciferase , transcription factor , phorbol , forskolin , protein kinase c , medicine , intracellular , gene expression , biology , signal transduction , biochemistry , in vitro , transplantation , gene , water channel , inlet , organic chemistry , engineering , mechanical engineering
The Ca 2+ /calcineurin regulated transcription factor, NFATc, has been shown to regulate aquaporin‐2 (AQP2) expression in renal collecting duct cells. Nitric oxide (NO) it is also implicated in AQP2 regulation. Therefore, the goal of this study was to investigate whether NO affects NFATc regulation of AQP2 promoter. MDCK cells were cotransfected with an AQP2 promoter luciferase reporter and a renilla luciferase plasmid. Cells were treated for 24 h with 1 μM ionomycin, (Io, calcium ionophore, NFATc activator), 100 nM phorbol 12‐myristate 13‐acetate (PMA, PKC\AP‐1 activator) in the presence or absence of 0.1 mM NONOate (NO donor) or 1μM cyclosporin A (CsA, calcineurin inhibitor) or 10μM ODQ (soluble guanylyl cyclase inhibitor). AQP2 promoter activity increased in cells treated with Io+PMA (2.1±0.1* fold from control). Incubation with NONOate in addition to Io+PMA produced a further increase in promoter activity (2.8±0.2* & ) that was attenuated by CsA (1.9±0.1* # ) and ODQ (2.0±0.1* # ). *p<0.05 vs. control, # p<0.05 vs. NO+Io+PMA, & p<0.05 vs. Io+PMA. NONOate did not have any effect by itself. Similar results were observed in cells transfected with a 9xNFAT‐luciferase reporter demonstrating that NFAT activity is enhanced by NO. Our data suggest that NO via cGMP has a synergic effect with Io+PMA in activating the AQP2 promoter in MDCK cells. NO could be enhancing NFATc nuclear import or reducing its export to enhance NFATc‐mediated AQP2 promoter activation. Supported by AHA SDG and HL088151.