氧化低密度脂蛋白下调血管内皮细胞表达Rictor

目的探讨氧化低密度脂蛋白对培养血管内皮细胞表达基因Rictor的影响。方法分离并培养人脐静脉内皮细胞,用不同浓度(10、20、40和80 mg/L)氧化低密度脂蛋白作用24 h后,用RT-PCR及Western blot检测Rictor的表达情况,并检测转染Rictor后,蛋白激酶Akt及eNOS磷酸化的变化,用硝酸还原酶还原法测定NO释放量。结果氧化低密度脂蛋白显著降低Rictor的mRNA及蛋白的表达量(P<0.01),使Rictor-mTOR复合物形成减少。转染Rictor后,不仅Rictor表达增加而且使蛋白激酶Akt及eNOS磷酸化增加;内皮细胞NO释放量增多(P<0.05)。结论影响内皮细胞表达Rictor,是氧化低密度脂蛋白诱发血管内皮细胞功能不良的重要机制之一。

Oxidized low density lipoprotein down-regulates expression of Rictor in vascular endothelial cells

Objective To investigate the effect of oxidized low density lipoprotein on the expression of Rictor in cultured vascular endothelial cells. Methods Human umbilical vein endothelial cells were isolated and cultured and incubated with oxidized low density lipoprotein (10, 20, 40, 80mg/L) for 24h. RT-PCR and Western blot were employed to detect the expression of Rictor mRNA and protein. The phosphorylation of Akt and eNOS were analyzed with Western blot. The contents of NO2-/NO3- in the culture medium were measured by nitrate reductase assay. Results Oxidized low density lipoprotein significantly down-regulated expression of Rictor mRNA and protein in endothelial cells (P<0.01) and decreased the amount of rictor-mTOR complex. In endothelial cells transfected with Rictor, increased expression of Rictor enhanced the phosphorylation of Akt and eNOS, and restored endothelial NO production. Conclusions The inhibition of Rictor expression by oxidized low density lipoprotein may play an important role in promoting endothelial dysfunction.