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Adenosine stimulates eNOS phosphorylation by a p42/44 MAPK‐dependent mechanism in microvascular endothelial cells
Author(s) -
Kalogeris Theodore J.,
Yusof Mozow,
Gaskin F. Spencer,
Korthuis Ronald J.
Publication year - 2008
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.22.1_supplement.1145.2
Subject(s) - enos , wortmannin , agonist , phosphorylation , adenosine , mapk/erk pathway , medicine , endocrinology , biology , antagonist , nitric oxide , receptor , chemistry , microbiology and biotechnology , nitric oxide synthase , protein kinase b
Adenosine (Ado) is a key mediator in the protective effects of ethanol preconditioning on microvascular function. In vivo studies indicate that Ado's protective effect mediated by increased activity of endothelial nitric oxide synthase (eNOS). However, the mechanism for Ado‐induced eNOS activation is not clear. In order to address this issue, we studied the effects of Ado, Ado agonists, and several antagonists on phosphorylation of eNOS Ser 1177 in human microvascular endothelial cells (HMEC‐1). Ado, CPCA (an Ado A2 receptor agonist), and NECA (an Ado A1/A2 receptor agonist) significantly increased eNOS phosphorylation within one minute of exposure, but CPA (A1 agonist) had no effect. The effects of Ado and NECA were partially blocked by the A2 receptor antagonist, DMPX, whereas DMPX completely reversed the effect of CPCA. A1 receptor antagonist, DPCPX, had no effect on Ado‐induced phosphorylation. Sp‐cAMPS, a cAMP agonist, increased phosphorylation; this was blocked by PI3K inhibitors, wortmannin and LY‐294002. Ado‐induced phosphorylation was unaffected by the cAMP antagonist, Rp‐cAMPS, wortmannin, and LY‐294002, but was reversed by p42/44 MAPK inhibitor, PD98,059. These results suggest that in HMEC‐1, Ado A2 receptor‐mediated activation of eNOS is independent of activity of either PKA or PKB, but is dependent upon activation of p42/44 MAPK. Supported by AA14945 and DK43785.