miR-22对脂多糖诱导的心肌损伤的研究

Effects of miR-22 on Lipopolysaccharide Induced Myocardial Cell Damage

目的探讨miR-22对脂多糖(LPS)诱导的心肌细胞损伤的保护作用及可能机制。方法采用LPS刺激H9c2大鼠心肌细胞诱导心肌细胞损伤模型。采用miR-22模拟物转染心肌细胞,将细胞随机分为4组,即对照组、LPS组、miR-22+LPS组和miR-NC+LPS组。RT-PCR法检测细胞中miR-22表达;MTT法检测细胞活性;TUNEL染色检测细胞凋亡;免疫印迹法检测相关蛋白的表达;通过双荧光素酶报告基因实验证实miR-22对靶基因的调控作用。结果miR-22的表达在LPS组显著低于对照组;MTT试验结果显示LPS组细胞活性明显低于对照组,miR-22+LPS组细胞活性高于LPS组;TUNEL染色显示LPS组细胞凋亡数量明显高于对照组,miR-22+LPS组细胞凋亡数量低于LPS组。与对照组比较,LPS组Bcl-2/Bax比值显著下降;与LPS组比较,miR-22+LPS组Bcl-2/Bax比值明显升高。RT-PCR和Western blot法检测结果表明,上调miR-22表达后,HMGB1蛋白表达和mRNA水平明显降低。双荧光素酶报告实验显示miR-22靶向调控HMGB1的mRNA的3′非编码区(3′UTR)。结论miR-22可能通过负向调控HMGB1的表达减轻LPS诱导的心肌细胞损伤。

Objective To investigate the effect and the mechanism of miR-22 on cardiomyocytes damage induced by lipopolysaccharide(LPS).Methods The damage model of cardiomyocytes was established by stimulating H9c2 cells with LPS.Cardiac myocytes were randomly divided into four groups:control group,LPS group,miR-22+LPS group and miR-NC+LPS group.The expression of miR-22 was detected by RT-PCR,cell viability and apoptosis were detected by MTT and TUNEL staining,HMGB1 and apoptosis-related protein(Bax,Bcl-2)were detected by Western blot.Target Scan prediction and dual luciferase reporter assay were performed to confirm the interaction between miR-22 and HMGB1.Results The expression of miR-22 was significantly decreased in LPS-induced H9c2 cells.Overexpression of miR-22 can significantly promote cell viability and inhibit cell apoptosis.The expression of apoptosis-related proteins in the miR-22+LPS group decreased significantly compared to LPS group.Dual luciferase reporter assay and western blot experiment showed that HMGB1 was a direct target of miR-22.Conclusion miR-22 may inhibit LPS-induced cardiomyocyte damage through negatively regulating HMGB1 expression.