title: Ox-LDL-induced LOX-1 expression in vascular smooth muscle cells: role of reactive oxygen species.
abstract: Oxidized low density lipoprotein (ox-LDL) and lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) have been implicated in the development of atherosclerosis. This study was designed to investigate the expression regulation of LOX-1 by ox-LDL and the potential underlying mechanisms in cultured rat vascular smooth muscle cells (VSMCs). VSMCs were treated with ox-LDL, and the expressions of LOX-1 mRNA and proteins were determined by RT-PCR and western blotting, respectively. The intracellular reactive oxygen species (ROS) production was monitored by flow cytometry with fluorescence probe, DCFH(2) -DA. The effect of several inhibitors including aspirin, NDGA, allopurinol, apocynin, and rotenone on ox-LDL-induced ROS formation and LOX-1 expression was also investigated. The roles of NF-κB p65 and JNK were explored. Ox-LDL significantly induced LOX-1 expression at both mRNA and protein levels in a dose-dependent and time-dependent manner. Aspirin, NDGA, and preconditioned apocynin suppressed ox-LDL-induced intracellular ROS production and LOX-1 expression, while allopurinol and rotenone failed to do so. Vitamin C and N-acetyl-l-cysteine demonstrated similar effect. Furthermore, both NF-κB p65 expression and phosphorylated JNK (p-JNK) to JNK expression ratio were elevated after ox-LDL treatment. In addition, the NF-κB inhibitor PDTC and JNK inhibitor SP600125 pretreatment partly abolished ox-LDL-induced LOX-1 expression. These findings suggested that ROS mediated ox-LDL-induced LOX-1 expression in VSMCs through NF-κB and JNK signaling pathways.
authors.affiliation: Chengdu Medical College, Chengdu, China.
authors.forename: Yiyi
authors.initials: Y
authors.lastname: Sun
authors.forename: Xiuping
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D002478:Cells, Cultured; D008078:Cholesterol, LDL / Q000097:blood; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D008077:Lipoproteins, LDL / Q000187:drug effects / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D051131:Receptors, Oxidized LDL / Q000502:physiology*; D051127:Scavenger Receptors, Class E / Q000502:physiology*; D015398:Signal Transduction; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D013997:Time Factors
chemical_list: D008078:Cholesterol, LDL; D008077:Lipoproteins, LDL; D016328:NF-kappa B; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D051131:Receptors, Oxidized LDL; D051127:Scavenger Receptors, Class E; D017392:Thiobarbituric Acid Reactive Substances; C099252:oxidized low density lipoprotein; D048031:JNK Mitogen-Activated Protein Kinases