NDRG2调控大鼠肝细胞周期的机制

The mechanism of NDRG2 regulating the hepatocyte cell cycle in the rats

目的:阐明NDRG2(N-Myc downstream-regulated gene 2)在大鼠肝再生过程中对肝细胞周期的调控机制。方法:大鼠70%肝切除后收集0 h、8 h、24 h、48 h、72 h、7 d、10 d的再生肝组织,采用Real-time PCR和Western blot方法检测大鼠肝再生过程中NDRG2基因和蛋白的动态变化。流式细胞仪检测腺病毒介导的高表达NDRG2对大鼠正常肝细胞系(BRL)细胞周期的影响。Real-time PCR和Western blot方法检测高表达NDRG2对肝细胞周期调控的分子机制。结果:NDRG2基因和蛋白的表达水平在肝再生达到高峰时明显下降,在肝细胞进入分化期时显著上调;流式细胞仪检测显示BRL细胞中高表达NDRG2 48 h后,G0/G1期细胞百分比从对照组39.30±1.97上升至57.44±2.56,S期从37.66±1.73下降至13.27±2.01,差异有统计学意义(P<0.05)。对周期调控相关分子的检测显示高表达NDRG2对肝细胞周期的影响是通过上调p21,抑制Cyclin E实现的。结论:NDRG2通过影响细胞周期参与调控大鼠肝再生过程。

Objective：To explore the mechanism of N-Myc downstream-regulated gene 2（NDRG2） regulating hepatocyte cell cycle in rat liver regeneration process.Methods：The rats were subjected to 70% partial hepatectomy.Liver samples were collected at the indi-cated time points following surgery（0 h,8 h,24 h,48 h,72 h,7d,10 d）.Real-time PCR and Western blot were performed to analyze the expressions of NDRG2.BRL cell lines were treated with AdNDRG2,AdLacZ or PBS for 48 h.Cell cycle were analyzed with a FACS Calibur flow cytometer.Related cell cycle regulators were analyzed after AdNDRG2 treatment by Real-time PCR and Western blot.Results：The levels of NDRG2 mRNA and proteins were strongly reduced when liver regeneration reached a peak of activity.In addition,after been transfected with adenovirus,the proportions of cells in G0/G1 phase increased from 39.30±1.97 in the AdLacZ group to 57.44±2.56 in the AdNDRG2 group.Meanwhile,cells in S phase droped from 37.66±1.73 to 13.27±2.01.Moreover,the ectopic expression of NDRG2 increased p21 level and decreased Cyclin E protein,which caused the G1/S arrest.Conclusion：NDRG2 regulated rat liver regeneration by its strong cell cycle inhibitory effect via affecting p21 and Cyclin E level.