高密度脂蛋白对THP-1巨噬细胞B类Ⅰ型清道夫受体的表达及胆固醇流出的影响

Influences of HDL on SR-BI expression and cholesterol efflux in THP-1 cells

目的:观察高密度脂蛋白(HDL)对THP-1巨噬细胞B类Ⅰ型清道夫受体(SR-BI)的表达及胆固醇流出的影响。方法:用HDL及氧化低密度脂蛋白(ox-LDL)处理THP-1细胞,采用RT-PCR、Western印迹及液体闪烁计数法观察细胞SR-BI的表达及细胞内胆固醇流出的变化。结果:ox-LDL下调THP-1巨噬细胞中SR-BI的表达,而HDL则上调THP-1巨噬细胞中SR-BI的表达;液体闪烁计数法检测发现ox-LDL减少细胞中胆固醇的流出,HDL可以增加细胞胆固醇的流出,且HDL的效应呈浓度依赖性。结论:HDL可能通过上调THP-1巨噬细胞SR-BI的表达,促进巨噬细胞内胆固醇流出。

Objective To investigate the influences of HDL on SR-BI expression and cholesterol efflux in THP-1 cell line. Methods THP-1 cells were treated with ox-LDL or HDL at different concentrations. [^3H]-labeled cholesterol flux was determined by liquid scintillation; expression levels of SR-BI mRNA and protein were determined by reverse transeription-polymerase chain reaction and Western blot, respectively. Results ox-LDL downregulated but HDL upregulated the expression of SR-BI in THP-1 cells in a dose-dependent manner. Ox-LDL decreased while HDL increased the efflux of intracellular cholesterol in a dose-dependent manner. Conclusions HDL may enhance the efflux of intracellular cholesterol by upregulating SR-BI expression in THP-1 cells.