糖基化终产物AGEs对U937巨噬细胞高密度脂蛋白受体(SR-BI)蛋白表达的影响

目的研究诱导分化及糖基化终产物对人单核/巨噬细胞(U937细胞)高密度脂蛋白受体(SR-BI)蛋白表达的影响.方法U937细胞经PMA诱导分化,并将不同浓度或同一浓度AGEs与诱导分化48h后的U937细胞共同孵育,用免疫细胞化学法和Western印迹法检测SR-BI蛋白的表达.结果诱导分化后U937细胞SR-BI表达在24、48h逐渐升高,72 h下降;100、200和400mg/L AGEs刺激后细胞表面SR-BI蛋白表达量分别是BSA组的1.44、2.38和2.77倍(P＜0.05);400mg/L的AGEs作用6、12、24、48h后,U937巨噬细胞SR-BI蛋白表达量分别为0 h的1.38、2.49、3.76和4.25倍(P＜0.05).结论诱导分化24及48h SR-BI蛋白表达逐渐增加,而分化72h蛋白表达下降;AGEs可增加U937巨噬细胞SR-BI蛋白表达且呈浓度和时间依赖性.

Effects of advanced glycation end products on expression of scavenger receptor class B type I (SR-BI) in U937 macrophages

[Objective] To learn the effects of differentiation and AGEs on expression of SR-BI in U937macrophages. [Methods] U937 cells were cultured with 100 nM PMA in order to differentiate to macrophages.U937 macrophages were cultured with AGEs at different concentration for 24 hours and at a concentration of 400mg/L for different time. A immunocytochemical method was used to detect SR-BI protein during the PMA-induced differentiation. Western blotting analysis was used to measure SR-BI protein expression stimulated by AGEs. [Results] Immunocytochemistry showed that after exposure of U937 cells to PMA for 24, 48, 72 hours, the average integrated optical density values of SR-BI protein expression in U937 cells were (15.94±3.56), (27.86±4.39) and (9.08±2.37), with the first two groups higher than that in 0 h group (7.76±1.74, P ＜0.05). Western Blot showed that exposure of U937 macrophages to AGEs at different concentrations (100, 200, 400 mg/L) for 24 hours resulted in a 1.44-fold, 2.38-fold and 2.77-fold increase in the expression of SR-BI protein in U937 macrophages comparing with BSA control group (P ＜0.05). Meanwhile, exposure of U937 macrophages to AGEs at the concentration of 400 mg/L for 6,12, 24, 48 hours resulted in 1.38-fold, 2.49-fold, 3.76-fold and 4.25-fold increase in the expression of SR-BI protein in U937 macrophages comparing with 0 h group(P＜0.05). [Conclusions] The data suggest that PMA-induced differentiation can increase the expression of SR-BI protein in U937 macrophages at 24, 48 hours, and decrease at 72 hours. U937 macrophages that were incubated in medium containing AGEs showed an increase in the expression of SR-BI protein in a time and dose dependent manner.