Direct activation of AMP-activated protein kinase stimulates nitric-oxide synthesis in human aortic endothelial cells

Valerie A. Morrow, Fabienne Foufelle, John M. C, Connell, John Petrie, Gwyn W. Gould, Ian P. Salt

    Research output: Contribution to journalArticle

    278 Citations (Scopus)

    Abstract

    Recent studies have indicated that endothelial nitric-oxide synthase (eNOS) is regulated by reversible phosphorylation in intact endothelial cells. AMP-activated protein kinase (AMPK) has previously been demonstrated to phosphorylate and activate eNOS at Ser-1177 in vitro, yet the function of AMPK in endothelium is poorly characterized. We therefore determined whether activation of AMPK with 5'-aminoimidazole-4-carboxamide ribonucleoside (AICAR) stimulated NO production in human aortic endothelial cells. AICAR caused the time- and dose-dependent stimulation of AMPK activity, with a concomitant increase in eNOS Ser-1177 phosphorylation and NO production. AMPK was associated with immunoprecipitates of eNOS, yet this was unaffected by increasing concentrations of AICAR. AICAR also caused the time- and dose-dependent stimulation of protein kinase B phosphorylation. To confirm that the effects of AICAR were indeed mediated by AMPK, we utilized adenovirus-mediated expression of a dominant negative AMPK mutant. Expression of dominant negative AMPK attenuated AICAR-stimulated AMPK activity, eNOS Ser-1177 phosphorylation and NO production and was without effect on AICAR-stimulated protein kinase B Ser-473 phosphorylation or NO production stimulated by insulin or A23187. These data suggest that AICAR-stimulated NO production is mediated by AMPK as a consequence of increased Ser-1177 phosphorylation of eNOS. We propose that stimuli that result in the acute activation of AMPK activity in endothelial cells stimulate NO production, at least in part due to phosphorylation and activation of eNOS. Regulation of endothelial AMPK therefore provides an additional mechanism by which local vascular tone may be controlled.
    Original languageEnglish
    Pages (from-to)31629-31639
    Number of pages11
    JournalJournal of Biological Chemistry
    Volume278
    Issue number34
    DOIs
    Publication statusPublished - Aug 2003

    Fingerprint Dive into the research topics of 'Direct activation of AMP-activated protein kinase stimulates nitric-oxide synthesis in human aortic endothelial cells'. Together they form a unique fingerprint.

    Cite this