KLF4通过mTOR/P70S6K途径激活细胞自噬减轻高糖诱导的足细胞损伤

KLF4 Activates Autophagy Via mTOR/P70S6K Pathway to Attenuate High Glucose-induced Podocyte Injury

目的:分析Krüppel样转录因子4(KLF4)对高糖诱导的足细胞损伤的影响及相关分子机制。方法:体外培养MPC5细胞,将MPC5细胞分为对照组(Control组)、高糖组(HG组)、高糖+空载质粒对照组(HG+NC组)、高糖+KLF4过表达组(HG+KLF4组)。采用qRT-PCR法检测细胞中KLF4 mRNA表达水平,CCK-8法测定细胞增殖活性,流式细胞术检测细胞凋亡,Western blot法检测细胞中相关蛋白表达水平。结果:与Control组比较,HG组MPC5细胞中KLF4 mRNA和蛋白表达量降低,细胞增殖活性降低,细胞凋亡率升高,细胞中突触足蛋白(synaptopodin)、足蛋白(podocin)、肾蛋白(nephrin)、微管相关蛋白轻链3-Ⅱ(LC3-Ⅱ)、Beclin1蛋白表达量降低,P62蛋白表达量、磷酸化哺乳动物雷帕霉素靶蛋白(p-mTOR)/mTOR和磷酸化核糖体40S小亚基S6蛋白激酶(p-P70S6K)/P70S6K比值升高;差异均有统计学意义(P<0.05)。与HG组比较,HG+KLF4组MPC5细胞中KLF4 mRNA和蛋白表达量升高,细胞增殖活性升高,细胞凋亡率降低,细胞中synaptopodin、podocin、nephrin、LC3-Ⅱ、Beclin1蛋白表达量升高,P62蛋白表达量、p-mTOR/mTOR和p-P70S6K/P70S6K比值降低,差异均有统计学意义(P<0.05)。结论:KLF4通过激活足细胞自噬减轻高糖诱导的足细胞损伤,其作用机制可能与调控mTOR/P70S6K信号通路有关。

Objective:To analyze the effect of Krüppel like factor 4(KLF4)on high glucose-induced podocyte injury and its related molecular mechanism.Methods:MPC5 cells were cultured in vitro and divided into control group(Control group),high glucose group(HG group),high glucose+empty plasmid control group(HG+NC group)and high glucose+KLF4 overexpression group(HG+KLF4 group).The expression of KLF4 mRNA was detected by qRT-PCR,the proliferation activity was detected by CCK-8,the apoptosis was detected by Flow cytometry,and the expression level of related protein was detected by Western blot.Results:Compared with Control group,the expression of KLF4 mRNA and protein of MPC5 cells in HG group decreased,the proliferation activity of MPC5 cells decreased,the apoptosis rate increased,the expression of synaptopdin,podocin,nephrin,microtubule associated protein light chain 3-Ⅱ(LC3-Ⅱ),Beclin1 protein in MPC5 cells decreased,and the expression of P62 protein,the ratio of phosphorylated mammalian target of rapamycin(p-mTOR)/mTOR and phosphorylated 70-kDa ribosomal protein S6 kinase(p-P70S6K)/P70S6K increased;The difference was statistically significant(P<0.05).Compared with HG Group,the expression of KLF4 mRNA and protein of MPC5 cells in HG+KLF4 group increased,the proliferation activity in MPC5 cell increased,the apoptosis rate decreased,the expression of synaptopdin,podocin,nephrin,LC3-Ⅱand Beclin1 protein increased,and the expression of P62 protein,the ratio of p-mTOR/mTOR and p-P70S6K/P70S6K decreased;The difference was statistically significant(P<0.05).Conclusion:KLF4 attenuates high glucose-induced podocyte injury by activating podocyte autophagy,and its mechanism may be related to the regulation of mTOR/P70S6K signaling pathway.