甲基化转移酶G9a介导的组蛋白修饰事件调控ATF3表达及神经元凋亡

目的探讨协同c-Jun/ATF2调控ATF3表达的染色质重塑事件及对神经元凋亡的作用。方法小脑颗粒神经元凋亡刺激后检测组蛋白H3乙酰化水平的变化与ATF3表达的变化。G9a抑制剂BIX-01294处理神经元,Western Blot检测ATF3的表达、H3的甲基化变化,核染色检测神经元的凋亡率。结果神经元凋亡时诱导ATF3表达,H3第4位赖氨酸乙酰化修饰(methyl-H3-K4)增加。BIX-01294浓度依赖地抑制H3第4位赖氨酸甲基化修饰,抑制ATF3表达,抑制神经元凋亡(P<0.05)。结论神经元凋亡时,G9a介导的H3第4位赖氨酸甲基化修饰调控ATF3表达及凋亡发生。

G9a-Mediated H3 Methylation Contributes to ATF3 Induction and Neuronal Apoptosis

Objective To investigate the specific chromatin remodeling event that assists c-Jun/ATF2 to regulate the target gene ATF3 and neuronal apoptosis. Methods Cerebellar granule neurons （CGNs） were cultured in vitro 7 days and subjected to basic media containing 5 mM KCl （5K） for inducing apoptosis. CGNs were administrated with 5K media containing 0.5μM, 1μM, 2μM G9a inhibitor BIX-01338 for 24 h, respectively. Cells were cultured in media containing DMSO as control. Neuronal nucleic was stained by Hoechst 33258 for apoptotic analysis. Western blot was performed to detect the level of ATF3 expression and H3 methylation. Results 5K treatment resulted in an upregulation of ATF3, paralleling with an increase of H3-K4 methylation. BIX-01338 treatment dose-dependently inhibited ATF3 expression and H3-K4 methylation, as well as apoptosis under 5K media （P 〈0.05）. Conclusions G9a mediated H3-K4 methylation promotes ATF3 expression and apoptosis induced by 5K.