Aβ通过Ash1l上调H3K4二甲基化水平抑制BDNF表达并介导海马神经元损伤

Upregulation of Ash1l-dependent H3K4Me2 Level to Inhibit BDNF Expression and Mediate Hippocampal Neuron Damage

目的在Aβ处理海马神经元后,观测H3K4甲基化水平的变化,以及BDNF表达和神经元死亡的改变。方法在Aβ处理后,用蛋白免疫印迹以及染色质免疫共沉淀方法检测神经元中总H3K4甲基化水平和BDNF启动子H3K4甲基化水平。在si RNA敲减Ash1l后,通过荧光定量PCR和酶联免疫吸附的方法检测BDNF表达。同时,使用MTT实验检测敲减Ash1l后Aβ诱导海马神经元损伤的改变。结果在Aβ处理海马神经元后,BDNF启动子和总H3K4甲基化水平均显著上升,而敲减Ash1l可以阻止这一现象。另外,在敲减Ash1l后,Aβ诱导的BDNF表达下调被抑制,同时海马神经元损伤也得到缓解。结论 Ash1l蛋白被发现可以在Aβ多肽下游调节BDNF启动子区的H3K4Me2水平,通过抑制BDNF的表达促进神经元的死亡。

Objective To explore the level of H3K4Me2,BDNF expression and the damage of hippocampal neurons after administration of Aβ. Methods The levels of H3K4Me2 in neurons and BDNF promoter were analyzed by Western blot and chromatin immunoprecipitation after treatment with Aβ. And the level of BDNF expression was measured by real-time quantitative PCR and ELISA after knocking down Ash1l by siRNAs. Moreover, the survival of hippocampal neurons was analyzed by MTT assays. Results Aβincreased the levels of H3K4Me2 in neurons and BDNF promoter, which were inhibited by Ash1l knock-down. Additionally, the reduction of mRNA and protein levels of BDNF by Aβ was also prevented after knocking down Ash1l. Moreover, Ash1l knock-down significantly improved the survival of hippocampal neurons after administration of Aβ. Conclusion Aβ up-regulates the H3K4Me2 level via Ash1l to inhibit BDNF expression and further mediate hippocampal neuron damage.