Early activation of the p42/p44(MAPK) pathway mediates adenosine-induced nitric oxide production in human endothelial cells: a novel calcium-insensitive mechanism

Article

关键词: L-ARGININE TRANSPORT;    PROTEIN-KINASE;    CYCLIC-AMP;    A(2B) RECEPTORS;    CULTURED HUMAN;    SYSTEM Y(+);    SYNTHASE;    RELAXATION;    CHANNELS;    RELEASE;   

DOI  :  10.1096/fasebj.16.12.1584

来源: SCIE

【 摘 要 】

Adenosine is released from the myocardium, endothelial cells, and skeletal muscle in ischemia and is an important regulator of coronary blood flow. We have already shown that acute (2 min) activation of A(2a) purinoceptors stimulates NO production in human fetal umbilical vein endothelial cells (1) and now report a key role for p42/p44 mitogen-activated protein kinases (p42/p44(MAPK)) in the regulation of the L-arginine-nitric oxide (NO) signaling pathway. Expression of mRNA for the A(2a)-, A(2b)-, and A(3) -adenosine receptor subtypes was abundant whereas A(1)-adenosine receptor mRNA levels were negligible. Activation of A(2a) purinoceptors by adenosine (10 muM) or the A(2a) receptor agonist CGS21680 (100 nM) resulted in an increase in L-arginine transport and NO release that was not mediated by changes in intracellular Ca2+, pH, or cAMP. Stimulation of endothelial cells with adenosine was associated with a membrane hyperpolarization and phosphorylation of p42/p44(MAPK). L-NAME abolished the adenosine-induced hyperpolarization and stimulation of L-arginine transport whereas sodium nitroprusside activated an outward potassium current. Genistein (10 muM) and PD98059 (10 muM), an inhibitor of MAPK kinase 1/2 (MEK1/2), inhibited adenosine-stimulated L-arginine transport, NO production, and phosphorylation of p42/p44(MAPK). We found no evidence for activation of eNOS via the serine/threonine kinase Akt/ PKB (protein kinase B) in adenosine-stimulated cells. Our results provide the first evidence that adenosine stimulates the endothelial cell L-arginine-NO pathway in a Ca2+-insensitive manner involving p42/p44(MAPK), with release of NO leading to a membrane hyperpolarization and activation of L-arginine transport.

【 授权许可】

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