脯氨酰异构酶1沉默抑制缺氧/复氧H9c2心肌细胞凋亡

Inhibitory effects of Pin1 silencing by siRNA on apoptosis of H9c2 cardiomyocytes induced by hypoxia/reoxygenation

目的:肽基脯氨酰顺反异构酶1(Pin1)在心血管疾病发病过程中发挥重要作用,本研究检测RNA干扰沉默Pin1对缺氧/复氧诱导的大鼠胚胎心肌细胞H9c2凋亡的影响及机制。方法:体外培养大鼠H9c2细胞,建立缺氧/复氧损伤模型,模拟体内缺血再灌注损伤;RT-q PCR和Western blot法检测Pin1的表达;将细胞分为空白对照组、缺氧/复氧组、缺氧/复氧组+转染Pin1 siRNA组、缺氧/复氧组+转染scramble siRNA组;MTT法测H9c2细胞存活率;用流式细胞术Annexin V/PI双染法检测细胞凋亡率;用Western blot法检测H9c2细胞Bax和Bcl-2蛋白表达;生化法检测Caspase-3的活性水平。结果:Pin1在缺氧/复氧H9c2细胞中呈现高表达;转染Pin1 siRNA后,Pin1的mRNA和蛋白表达水平均显著降低(P<0.05);与缺氧/复氧组比较,Pin1 siRNA组的细胞存活率增加,凋亡率降低,Bcl-2蛋白表达升高,Bax蛋白表达降低,Bcl-2/Bax升高,Caspase-3活性降低,差异均有统计学意义(P<0.05)。结论:Pin1下调可减少缺氧/复氧诱导的心肌细胞凋亡,可能是通过上调Bcl-2,下调Bax蛋白表达,降低Caspase-3活性而发挥作用。

Objective:Pin1 plays an important role in the pathogenesis of cardiovascular disease,our study aims to investigate the effects of Pin1 silencing by siRNA on H9c2 apoptosis induced by hypoxia/reoxygenation.Methods:H9c2 cells were cultured and subjected to a hypoxia/reoxygenation(H/R)condition in vitro,mimicking ischemic/reperfusion injury in vivo.The mRNA and protein expression of Pin1 were detected by RT-qPCR and Western blot.H9c2 cells were divided into control group,H/R group,H/R+Pin1 siRNA group,H/R+scramble siRNA group.MTT and flow cytometry with Annexin V-FITC/PI staining were respectively performed to detect cell viability and apoptosis.The expression of Bax and Bcl-2 were measured by Western blot.The activity of Caspase-3 was detected by automatic biochemistry analytic instrument.Results:The mRNA and protein levels of Pin1 were highly expressed in the cells of H/R group.Transfection with Pin1 siRNA strikingly inhibited the expression of Pin1.Compared with H/R group,Pin1 siRNA markedly increased cell viability,decreased the cell apoptosis and the Caspase-3 activity.Furthermore,the increased Bcl-2,decreased Bax and the ratio of Bcl-2 to Bax were observed in Pin1 siRNA group(P<0.05)compared with H/R group.Conclusion:Downregulation of Pin1 protects hypoxia/reoxygenation-injured H9c2 cells from apoptosis,which is possibly through the upregulation of Bcl-2 and downregulation of Bax and Caspase-3 activity.