氧化型低密度脂蛋白诱导分子伴侣GRP78在3T3-L1脂肪细胞中的表达

Expression of chaperone glucose-regulated protein 78 kD induced by oxidized low density lipoprotein in 3T3-L1 adipocytes

目的观察氧化型低密度脂蛋白(ox-LDL)诱导3T3-L1脂肪细胞内质网应激相关分子伴侣葡萄糖调节蛋白78(GRP78)的表达,探讨ox-LDL对脂肪细胞内质网应激的诱导作用。方法体外培养3T3-L1脂肪细胞,分别给予不同浓度ox-LDL(50,100,200μg/ml)及内质网应激阳性对照诱导剂衣霉素(Tun)处理。用RT-PCR检测GRP78 mRNA的表达,筛选出最佳干预浓度,用最佳浓度的ox-LDL分别干预脂肪细胞6、12、24 h,分别用RT-PCR、Western印迹法检测GRP78 mRNA、蛋白表达情况。结果 ox-LDL呈浓度依赖方式诱导脂肪细胞GRP78表达,其表达强度随时间延长而增强,24 h达高峰(P<0.05)。结论 ox-LDL可诱导3T3-L1脂肪细胞发生内质网应激,促使未折叠蛋白反应信号通路的分子伴侣表达增加。

Objective To observe the expression of endoplasmic reticulum stress（ERS） related chaperone glucose-regulated protein 78 kD（GRP78） in 3T3-L1 adipocytes treated with oxidized low density protein（ox-LDL）,and investigate the effect of ox-LDL on the induction of ERS in 3T3-L1 adipocytes.Methods 3T3-L1 adipocytes were cultured and treated with ox-LDL（50,100,200 μg/ml） and tunicamycin（Tun,5 μg/ml） was treated as ERS positive control.RT-PCR was used to detect the mRNA expression of GRP78,and the most appropriate concentration was selected to treat adipocytes for 6,12 and 24 hours.Western blot was used to detect the protein levels of GRP78.Results The expression of GRP78 was induced in concentration-depended manner,increased with time extending,reached peak at 24 hours（P0.05）.Conclusions ox-LDL may induce ERS and increase the expression of chaperone of unfolded protein response in 3T3-L1 adipocytes.