MG132对高糖刺激的肾系膜细胞中Smurf2表达的作用

Effect of MG132 on expression of Smurf 2 in glomerular mesangial cells induced by high glucose

目的观察不同浓度高糖刺激后大鼠肾小球系膜细胞胞内Smad泛素化调节因子-Smurf2的表达,并以蛋白酶体抑制剂MG132作为阻断剂,探讨泛素化降解在糖尿病肾病中的作用。方法将体外培养的大鼠肾系膜细胞分别设正常对照组(葡萄糖浓度5.6mmol/L)、20mmol/L高糖组、30mmol/L高糖组、30mmol/L高糖加MG132组等。分别用Real time Quantitative PCR法和细胞免疫荧光染色法及激光共聚焦显微镜检测各组细胞泛素连接酶Smurf2的mRNA和蛋白表达。结果①正常组细胞Smurf2的mRNA和蛋白表达较弱,高糖组Smurf2表达较正常组增强(P<0.05),呈浓度依赖性;②30mmol/L高糖组加入MG132后,Smurf2的mRNA和蛋白表达减弱。结论高糖可诱导肾系膜细胞Smurf2表达增强,MG132可阻止高糖所导致的上述变化。提示泛素-蛋白酶体途径参与了糖尿病肾病的发病。

[ Objective ] To observe the expression of smad ubiquition regulatory factor Smurf 2 in rat glomerular mesangial cells （GMC） stimulated by the high concentration of glucose, and to investigate the effect of the ubiquition in diabetic, nephropathy by adding MG132 as a proteasome differential inhibitor.[Methods] Cultured rat GMC were divided into normal group（the concentration of glucose：5.6 mmol/L）, high glucose group（20, 30 mmol/L respectively）, therapy group （30 mmo]/L glucose with MG132） . The expression of Smurf 2 mRNA in each group was measured by quantitative RT-PCR and protein was measured by indirect immunfluoreseence and laser scanning confocal microscope respectively.[Results] （1）The expression of Smurf 2 of GMC in normal group was weak, whereas the expression of Smuff 2 in high glucose group was stronger than that in normal group （P 〈0.05）, in a concentrationdependent manner.（2）In therapy group（30 mmol/L glucose with MG132 group）, the expression of Smurf 2 was found weakened. [Conclusions] High glucose increase the expression of Smurf 2 in glomerular mesanglal cells. MG132 can prevent the increased expression of Smuff 2 induced by high glucose. Ubiquition-proteasome pathway （lAPP） is related with the regulation of smad signal transduction pathways in diabetic nephropathy.