Role of reactive oxygen species and NAD(P)H oxidase in alpha(1)-adrenoceptor signaling in adult rat cardiac myocytes.

Xiao L, Pimentel DR, Wang J, Singh K, Colucci WS, Sawyer DB
Am J Physiol Cell Physiol. 2002 282 (4): C926-34

PMID: 11880281 · DOI:10.1152/ajpcell.00254.2001

We recently reported that alpha(1)-adrenoceptor (alpha(1)-AR) stimulation induces hypertrophy via activation of the mitogen/extracellular signal-regulated kinase (MEK) 1/2-extracellular signal-regulated kinase (ERK) 1/2 pathway and generates reactive oxygen species (ROS) in adult rat ventricular myocytes (ARVM). Here we investigate the intracellular source of ROS in ARVM and the mechanism by which ROS activate hypertrophic signaling after alpha(1)-AR stimulation. Pretreatment of ARVM with the ROS scavenger Mn(III)terakis(1-methyl-4-pyridyl) porphyrin pentachloride (MnTMPyP) completely inhibited the alpha(1)-AR-stimulated activation of Ras-MEK1/2-ERK1/2. Direct addition of H(2)O(2) or the superoxide generator menadione activated ERK1/2, which is also prevented by MnTMPyP pretreatment. We found that ARVM express gp91(phox), p22(phox), p67(phox), and p47(phox), four major components of NAD(P)H oxidase, and that alpha(1)-AR-stimulated ERK1/2 activation was blocked by four structurally unrelated inhibitors of NAD(P)H oxidase [diphenyleneiodonium, phenylarsine oxide, 4-(2-aminoethyl)benzenesulfonyl fluoride, and cadmium]. Conversely, inhibitors for other potential ROS-producing systems, including mitochondrial electron transport chain, nitric oxide synthase, xanthine oxidase, and cyclooxygenase, had no effect on alpha(1)-AR-stimulated ERK1/2 activation. Taken together, our results show that ventricular myocytes express components of an NAD(P)H oxidase that appear to be involved in alpha(1)-AR-stimulated hypertrophic signaling via ROS-mediated activation of Ras-MEK1/2-ERK1/2.

MeSH Terms (26)

Age Factors Animals Cardiomegaly Cells, Cultured Enzyme Inhibitors Gene Expression Regulation, Enzymologic Male MAP Kinase Kinase 1 MAP Kinase Kinase 2 MAP Kinase Signaling System Mitochondria Mitogen-Activated Protein Kinase 1 Mitogen-Activated Protein Kinase 3 Mitogen-Activated Protein Kinase Kinases Mitogen-Activated Protein Kinases Muscle Fibers, Skeletal Myocardium NADPH Oxidases Protein-Serine-Threonine Kinases Protein-Tyrosine Kinases ras Proteins Rats Rats, Sprague-Dawley Reactive Oxygen Species Receptors, Adrenergic, alpha-1 RNA, Messenger

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