SIRT3抑制PARP-1活性缓解多巴胺能神经元炎症损伤

SIRT3 expression alleviates inflammatory damage of dopaminergic neurons by inhibiting PARP-1 activity

目的研究多巴胺能神经元SIRT3表达对小胶质细胞活化所致其炎症损伤的抵抗作用及相关机制。方法建立多巴胺能神经元MN9D细胞与小胶质细胞BV-2共培养体外炎症损伤模型。将MN9D细胞分为对照组、模型组、SIRT3组、SIRT3+PJ34(PARP-1抑制剂)组。实时定量聚合酶链式反应分析mRNA水平,流式细胞术检测细胞凋亡率,JC-1法检测线粒体膜电位变化,酯化钙黄绿素与氯化钴共孵育法分析线粒体通透性转运孔(mPTP)开放情况,Western blot检测蛋白表达情况。结果与模型组比较,SIRT3过表达则使SIRT3组MN9D细胞的凋亡率明显降低,SIRT3和SOD_(2)基因表达明显增多,PARP-1、TNF-α及IL-1β蛋白表达明显减少,p-NF-κB p65/NF-κB p65比值明显变小,线粒体膜电位上升,mPTP开放和ROS生成减少,组间比较差异均具有统计学意义(P<0.05);SIRT3+PJ34组MN9D细胞PARP-1活性抑制后,除SIRT3和IL-1β蛋白表达变化不明显外,其它考察指标的变化趋势在SIRT3组基础上进一步增大,两组间比较差异均具有统计学意义(P<0.05)。结论SIRT3表达能够缓解小胶质细胞激活所致多巴胺能神经元的炎症损伤,机制可能与其改善线粒体功能,减少ROS生成抑制PARP-1活性及NF-κB信号通路有关。

Aim To study the resistance of SIRT3 expression in dopaminergic neurons against the inflammatory damage caused by microglia activation and its related mechanism.Methods Dopaminergic neurons(MN9D cells)and microglia(BV-2 cells)were co-cultured to establish an inflammatory injury model in vitro.MN9D cells were divided into the control group,model group,SIRT3 group and SIRT3+PJ34 group.mRNA levels were analyzed by real-time quantitative polymerase chain reaction,cell apoptosis rate was detected by flow cytometry,changes in mitochondrial membrane potential were tested by JC-1 method,and the opening of mitochondrial permeability transport pore(mPTP)was analyzed by co-incubation of calcein-AM and CoCl_(2).The protein expression was detected by Western blot.Results Compared to the model group,overexpression of SIRT3 in the SIRT3 group significantly reduced the apoptosis rate of MN9D cells.It also led to a significant increase in the expression of SIRT3 and SOD_(2)genes,as well as a notable decrease in PARP-1,tumor necrosis factor-α,and interleukin 1β(IL-1β)protein expressions.Moreover,it resulted in a substantial reduction in the p-NF-κB p65/NF-κB p65 ratio.There was an improvement observed in mitochondrial membrane potential along with decreased mPTP opening and ROS production in the SIRT3 group.These differences among these groups were statistically significant(all P<0.05).After inhibiting PARP-1 activity of MN9D cells in the SIRT3+PJ34 group,except for the insignificant changes in SIRT3 and IL-1βprotein expression,the changing trend of other indicators was further enhanced on the basis of SIRT3 group.The differences between two groups remained statistically significant(all P<0.05).Conclusions SIRT3 expression can attenuate the inflammatory damage of dopaminergic neurons induced by microglia activation,and the mechanism may be related to improving mitochondrial function,inhibiting PARP-1 activity and NF-κB signaling pathway caused by the reduction of ROS production.