Role of reactive oxygen species and NAD(P)H oxidase in alpha(1)-adrenoceptor signaling in adult rat cardiac myocytes.
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.
Xiao
Lei
L
Myocardial Biology Unit, Cardiovascular Division, Department of Medicine, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA.
Pimentel
David R
DR
Wang
Jing
J
Singh
Krishna
K
Colucci
Wilson S
WS
Sawyer
Douglas B
DB
D000367:Age Factors; D000818:Animals; D006332:Cardiomegaly / Q000378:metabolism; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism / Q000473:pathology; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism
D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D018340:Receptors, Adrenergic, alpha-1; D019255:NADPH Oxidases; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases; D018631:ras Proteins