Zhang Zhentao, Wang Tao, Cao Xuebing, Sun Shenggang, Wang Lan
Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
J Huazhong Univ Sci Technolog Med Sci. 2009 Feb;29(1):97-100. doi: 10.1007/s11596-009-0121-5. Epub 2009 Feb 18.
This study investigated the effect and mechanism of cell cycle reentry induced by 6-hydrodopamine (6-OHDA) in PC12 cells. By using neural differentiated PC12 cells treated with 6-OHDA, the apoptosis model of dopaminergic neurons was established. Cell viability was measured by MTT. Cell apoptosis and the distribution of cell cycle were assessed by flow cytometry. Western blot was used to detect the activation of extracellular regulator kinase1/2 (ERK1/2) pathway and the phosphorylation of retinoblastoma protein (RB). Our results showed that after PC12 cells were treated wtih 6-OHDA, the viability of PC12 cells was declined in a concentration-dependent manner. Flow cytometry revealed that 6-OHDA could increase the apoptosis ratio of PC12 cells in a time-dependent manner. The percentage of cells in G0/G1 phase of cell cycle was decreased and that in S phase and G2/M phase increased. Simultaneously, ERK1/2 pathway was activated and phosphorylated RB increased. It was concluded that 6-OHDA could induce cell cycle reentry of dopaminergic neurons through the activation of ERK1/2 pathway and RB phosphorylation. The aberrant cell cycle reentry contributes to the apoptosis of dopaminergic neurons.
本研究探讨了6-羟基多巴胺（6-OHDA）诱导PC12细胞重新进入细胞周期的作用及机制。通过用6-OHDA处理神经分化的PC12细胞，建立了多巴胺能神经元的凋亡模型。采用MTT法检测细胞活力。通过流式细胞术评估细胞凋亡及细胞周期分布。利用蛋白质免疫印迹法检测细胞外调节激酶1/2（ERK1/2）通路的激活情况及视网膜母细胞瘤蛋白（RB）的磷酸化水平。结果显示，PC12细胞经6-OHDA处理后，其活力呈浓度依赖性下降。流式细胞术显示，6-OHDA可使PC12细胞的凋亡率呈时间依赖性增加。细胞周期G0/G1期的细胞百分比降低，S期和G2/M期的细胞百分比增加。同时，ERK1/2通路被激活，RB磷酸化水平升高。研究得出结论，6-OHDA可通过激活ERK1/2通路和RB磷酸化诱导多巴胺能神经元重新进入细胞周期。异常的细胞周期重新进入导致多巴胺能神经元凋亡。
