Lysophosphatidylcholine activates extracellular signal-regulated kinases 1/2 through reactive oxygen species in rat vascular smooth muscle cells.
Lysophosphatidylcholine (lysoPC) acts on vascular smooth muscle cells (VSMCs) to produce a mitogenic response through the activation of extracellular signal-regulated kinases 1/2 (ERK1/2). In the present study, we examined the importance of reactive oxygen species (ROS) in lysoPC-stimulated ERK1/2 activation in cultured rat VSMCs. Treatment with lysoPC for 3 minutes caused a 2-fold increase in intracellular ROS that was blocked by the NADH/NADPH oxidase inhibitor, diphenylene iodonium (DPI). Antioxidants, N-acetyl-L-cysteine, glutathione monoester, or alpha -tocopherol, inhibited ERK1/2 activation by lysoPC. Almost identical results were obtained in the VSMC line A10. Pretreatment of VSMCs with DPI but not allopurinol or potassium cyanide (KCN) abrogated the activation of ERK1/2. The Flag-tagged p47phox expressed in A10 cells was translocated from the cytosol to the membrane after 2 minutes of stimulation with lysoPC. The overexpression of dominant-negative p47phox in A10 cells suppressed lysoPC-induced ERK activation. The ROS-dependent ERK activation by lysoPC seems to involve protein kinase C- and Ras-dependent raf-1 activation. Induction of c-fos expression and enhanced AP-1 binding activity by lysoPC were also inhibited by DPI and NAC. Taken together, these data suggest that ROS generated by NADH/NADPH oxidase contribute to lysoPC-induced activation of ERK1/2 and subsequent growth promotion in VSMCs.
Yamakawa
Tadashi
T
Department of Endocrinology and Diabetes, Yokohama City University Medical Center, Minami-ku, Yokohama, Japan. yamakat@ urahp.yokohama-cu.ac.jp
Tanaka
Shun-ichi
S
Yamakawa
Yuko
Y
Kamei
Junzo
J
Numaguchi
Kotaro
K
Motley
Evangeline D
ED
Inagami
Tadashi
T
Eguchi
Satoru
S
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008244:Lysophosphatidylcholines / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology*; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000502:physiology; D009861:Onium Compounds / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism
D000975:Antioxidants; D008244:Lysophosphatidylcholines; D009861:Onium Compounds; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; C007517:diphenyleneiodonium; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases; D019908:Proto-Oncogene Proteins c-raf; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D016283:Proto-Oncogene Proteins p21(ras); D000111:Acetylcysteine