title: Antioxidants inhibit JNK and p38 MAPK activation but not ERK 1/2 activation by angiotensin II in rat aortic smooth muscle cells.
abstract: Angiotensin II (Ang II) induces vascular smooth muscle cell (VSMC) hypertrophy, which results in several cardiovascular diseases. Ang II-induced cellular events have been mediated, in part, by reactive oxygen species (ROS) which also involve activation of mitogen-activated protein (MAP) kinases. Although it has been proposed that the therapeutic administration of antioxidants is useful for vascular diseases, the precise mechanisms which regulate ROS-sensitive signaling events have not been well characterized. Thus, we hypothesized that antioxidants may affect ROS-mediated MAP kinases activation induced by Ang II. The present findings showed that Ang II stimulated rapid and significant activation of ERK 1/2, JNK and p38 MAPK in cultured rat aortic smooth muscle cells (RASMC). Ang II-induced ERK 1/2 activation was not affected by all antioxidants examined, whereas JNK was sensitive to all antioxidants. In contrast, p38 MAPK activation was inhibited by DPI and ascorbic acid concentration-dependently, but by NAC only at high concentration. DETC and Trolox C had no effects on p38 MAPK activation by Ang II. We further examined the effects of antioxidants on Ang II-induced increases in oxygen consumption as an index of ROS generation in RASMC. DPI strongly inhibited Ang II-induced increases in oxygen consumption. DETC also inhibited Ang II-induced oxygen consumption, whereas ascorbic acid markedly augmented it. These findings suggest that the inhibitory effects of antioxidants on MAP kinases activation in VSMC are attributable, in part, to their modulating effects on ROS generation by Ang II in VSMC. Thus, inhibition of MAP kinases by antioxidants may imply their usefulness for relief of cardiovascular diseases.
authors.affiliation: Department of Pharmacology, The University of Tokushima School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kyaw
authors.forename: M
authors.initials: M
authors.lastname: Yoshizumi
authors.forename: K
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: K
authors.initials: K
authors.lastname: Kirima
authors.forename: T
authors.initials: T
authors.lastname: Tamaki
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001013:Aorta, Thoracic / Q000166:cytology; D001205:Ascorbic Acid / Q000494:pharmacology; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D002839:Chromans / Q000494:pharmacology; D004050:Ditiocarb / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D009861:Onium Compounds / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D000975:Antioxidants; D002614:Chelating Agents; D002839:Chromans; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D009861:Onium Compounds; D017382:Reactive Oxygen Species; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; C007517:diphenyleneiodonium; D004050:Ditiocarb; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D001205:Ascorbic Acid; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; D000111:Acetylcysteine