Abstract
Aim:
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.
Conclusion:
Ezetimibe suppresses cholesterol accumulation in rat VSMCs in vitro by regulating SREBP-1 and caveolin-1 expression, possibly via the MAPK signaling pathway.
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Acknowledgements
This work was supported by grants from the National Natural Science Foundation of China (No 81000946, No 81270359, No 81173047, and No 12JJ5068) and the construct program of the Pharmaceutical Science key discipline in Hunan province.
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Qin, L., Yang, Yb., Yang, Yx. et al. Ezetimibe suppresses cholesterol accumulation in lipid-loaded vascular smooth muscle cells in vitro via MAPK signaling. Acta Pharmacol Sin 35, 1129–1136 (2014). https://doi.org/10.1038/aps.2014.10
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DOI: https://doi.org/10.1038/aps.2014.10
