title: Ezetimibe suppresses cholesterol accumulation in lipid-loaded vascular smooth muscle cells in vitro via MAPK signaling.
abstract: OBJECTIVE
  To investigate the mechanisms of anti-atherosclerotic action of ezetimibe in rat vascular smooth muscle cells (VSMCs) in vitro.
  
  
  METHODS
  VSMCs of SD rats were cultured in the presence of Chol:MβCD (10 μg/mL) for 72 h, and intracellular lipid droplets and cholesterol levels were evaluated using Oil Red O staining, HPLC and Enzymatic Fluorescence Assay, respectively. The expression of caveolin-1, sterol response element-binding protein-1 (SREBP-1) and ERK1/2 were analyzed using Western blot assays. Translocation of SREBP-1 and ERK1/2 was detected with immunofluorescence.
  
  
  RESULTS
  Treatment with Chol:MβCD dramatically increased the cellular levels of total cholesterol (TC), cholesterol ester (CE) and free cholesterol (FC) in VSMCs, which led to the formation of foam cells. Furthermore, Chol:MβCD treatment significantly decreased the expression of caveolin-1, and stimulated the expression and nuclear translocation of SREBP-1 in VSMCs. Co-treatment with ezetimibe (3 μmol/L) significantly decreased the cellular levels of TC, CE and FC, which was accompanied by elevation of caveolin-1 expression, and by a reduction of SREBP-1 expression and nuclear translocation. Co-treatment with ezetimibe dose-dependently decreased the expression of phosphor-ERK1/2 (p-ERK1/2) in VSMCs. The ERK1/2 inhibitor PD98059 (50 μmol/L) altered the cholesterol level and the expression of p-ERK1/2, SREBP-1 and caveolin-1 in the same manner as ezetimibe did.
  
  
  CONCLUSIONS
  Ezetimibe suppresses cholesterol accumulation in rat VSMCs in vitro by regulating SREBP-1 and caveolin-1 expression, possibly via the MAPK signaling pathway.
authors.affiliation: 1] Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China [2] Institute of Pharmacy and Pharmacology, South China University, Hengyang 421001, China.
authors.forename: Li
authors.initials: L
authors.lastname: Qin
authors.affiliation: 1] Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China [2] Matthew Mailing Centre for Translational Transplantation Studies, London Health Sciences Centre, Western University, London N6A5A5, Canada [3] The Second Xiang-Ya Hospital, Central South University, Changsha 410011, China.
authors.forename: Yun-bo
authors.initials: YB
authors.lastname: Yang
authors.affiliation: Matthew Mailing Centre for Translational Transplantation Studies, London Health Sciences Centre, Western University, London N6A5A5, Canada.
authors.forename: Yi-xin
authors.initials: YX
authors.lastname: Yang
authors.affiliation: 1] The Second Xiang-Ya Hospital, Central South University, Changsha 410011, China [2] The Second Affiliated Hospital, South China University, Hengyang 421001, China.
authors.forename: Neng
authors.initials: N
authors.lastname: Zhu
authors.affiliation: 1] Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China [2] Department of Pharmacology, Central South University, Changsha 410011, China.
authors.forename: Yong-zhen
authors.initials: YZ
authors.lastname: Gong
authors.affiliation: Institute of Pharmacy and Pharmacology, South China University, Hengyang 421001, China.
authors.forename: Cai-ping
authors.initials: CP
authors.lastname: Zhang
authors.affiliation: Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
authors.forename: Shun-xiang
authors.initials: SX
authors.lastname: Li
authors.affiliation: Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 410208, China.
authors.forename: Duan-fang
authors.initials: DF
authors.lastname: Liao
mesh_terms: D000818:Animals; D001384:Azetidines / Q000494:pharmacology*; D002784:Cholesterol / Q000378:metabolism*; D000069438:Ezetimibe; D008055:Lipids / Q000502:physiology*; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D001384:Azetidines; D008055:Lipids; D002784:Cholesterol; D020928:Mitogen-Activated Protein Kinases; D000069438:Ezetimibe
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