Reactive oxygen species mediate Endothelin-1-induced activation of ERK1/2, PKB, and Pyk2 signaling, as well as protein synthesis, in vascular smooth muscle cells.
Reactive oxygen species (ROS) have been shown to mediate the effects of several growth factors and vasoactive peptides, such as epidermal growth factor, platelet-derived growth factor, and angiotensin II (AII). Endothelin-1 (ET-1) is a vasoactive peptide which also exhibits mitogenic activity in vascular smooth muscle cells (VSMCs), and is believed to contribute to the pathogenesis of vascular abnormalities such as atherosclerosis, hypertension, and restenosis after angioplasty. However, a possible role for ROS generation in mediating the ET-1 response on extracellular signal-regulated kinases 1 and 2 (ERK1/2), protein kinase B (PKB), and protein tyrosine kinase 2 (Pyk2), key components of the growth-promoting and proliferative signaling pathways, has not been examined in detail. Our aim was to investigate the involvement of ROS in ET-1-mediated activation of ERK1/2, PKB, and Pyk2 in A-10 VSMCs. ET-1 stimulated ERK1/2, PKB, and Pyk2 phosphorylation in a dose- and time-dependent manner. Pretreatment of A-10 VSMCs with diphenyleneiodonium (DPI), an inhibitor of reduced nicotinamide adenine dinucleotide phosphate oxidase, attenuated ET-1-enhanced ERK1/2, PKB, and Pyk2 phosphorylation. In addition, in parallel with an inhibitory effect on the above signaling components, DPI also blocked ET-1-induced protein synthesis. ET-1 was also found to increase ROS production, which was suppressed by DPI treatment. N-Acetylcysteine, a ROS scavenger, exhibited a response similar to that of DPI and inhibited ET-1-stimulated ERK1/2, PKB, and Pyk2 phosphorylation. These results demonstrate that ROS are critical mediators of ET-1-induced signaling events linked to growth-promoting proliferative and hypertrophic pathways in VSMCs.
Daou
Grace Bou
GB
Research Center, Centre hospitalier de l'Université de Montréal - Hôtel-Dieu, Department of Medicine and Physiology, Université de Montréal, Quebec, Canada.
Srivastava
Ashok K
AK
D000818:Animals; D001011:Aorta / Q000473:pathology; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000378:metabolism*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051418:Focal Adhesion Kinase 2; D007930:Leucine / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000473:pathology*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017382:Reactive Oxygen Species; D015398:Signal Transduction; D013997:Time Factors
D019332:Endothelin-1; D004791:Enzyme Inhibitors; D009861:Onium Compounds; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; C007517:diphenyleneiodonium; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; C496054:Ptk2b protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D007930:Leucine