title: Mechanism of the inhibitory effect of atorvastatin on leptin expression induced by angiotensin II in cultured human coronary artery smooth muscle cells.
abstract: Leptin contributes to the pathogenesis of atherosclerosis. Ang II (angiotensin II), a proatherogenic cytokine, increases leptin synthesis in cultured adipocytes. Statin suppresses leptin expression in adipocytes and human coronary artery endothelial cells. However, the effect of Ang II and statin on leptin expression in VSMCs (vascular smooth muscle cells), the major cell types in atheroma, is poorly understood. Thus the aim of the present study was to investigate the molecular mechanism of atorvastatin for reducing leptin expression after Ang II stimulation in VSMCs. VSMCs from human coronary artery were cultured. Ang II stimulation increased leptin protein and mRNA and phospho-JNK (c-Jun N-terminal kinase) expression. Exogenous addition of Dp44mT (2,2'-dipyridyl-N,N-dimethylsemicarbazone) and mevalonate increased leptin protein expression similarly to Ang II. Atorvastatin, SP600125, JNK siRNA (small interfering RNA) and NAC (N-acetylcysteine) completely attenuated the leptin and phospho-JNK protein expression induced by Ang II. Ang II significantly increased ROS (reactive oxygen species) formation in human VSMCs. Addition of atorvastatin and NAC significantly attenuated the formation of ROS induced by Ang II. Addition of atorvastatin and SP600125 inhibited the phosphorylation of Rac1 induced by Ang II. The gel shift and promoter activity assay showed that Ang II increased AP-1 (activator protein-1)-binding activity and leptin promoter activity, while SP600125, NAC and atorvastatin inhibited the AP-1-binding activity and leptin promoter activity induced by Ang II. Ang II significantly increased the migration and proliferation of cultured VSMCs, while addition of atorvastatin, SP600125, NAC and leptin siRNA before Ang II stimulation significantly inhibited the migration and proliferation of VSMCs induced by Ang II. Ang II significantly increased secretion of leptin from human VSMCs, and addition of SP600125, atorvastatin and NAC before Ang II stimulation almost completely inhibited the leptin secretion induced by Ang II. In conclusion, Ang II induces leptin expression in human VSMCs, and atorvastatin could inhibit the leptin expression induced by Ang II. The inhibitory effect of atorvastatin on Ang II-induced leptin expression was mediated by Rac, ROS and JNK pathways.
authors.affiliation: Division of Cardiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Kou-Gi
authors.initials: KG
authors.lastname: Shyu
authors.forename: Shih-Chung
authors.initials: SC
authors.lastname: Chen
authors.forename: Bao-Wei
authors.initials: BW
authors.lastname: Wang
authors.forename: Wen-Pin
authors.initials: WP
authors.lastname: Cheng
authors.forename: Huei-Fong
authors.initials: HF
authors.lastname: Hung
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000924:Anticholesteremic Agents / Q000494:pharmacology; D000069059:Atorvastatin; D015153:Blotting, Western; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology; D006538:Heptanoic Acids / Q000494:pharmacology*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D020738:Leptin / Q000235:genetics / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D011758:Pyrroles / Q000494:pharmacology*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D000924:Anticholesteremic Agents; D006538:Heptanoic Acids; D020738:Leptin; D011758:Pyrroles; C107953:RAC1 protein, human; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D000069059:Atorvastatin; D048031:JNK Mitogen-Activated Protein Kinases; D020830:rac1 GTP-Binding Protein