花生四烯酸代谢产物EET调控线粒体动力学促进脑缺血损伤后的神经元恢复研究

The neuronal injury after ischemia/reperfusion is an important pathological process of ischemic stroke. The main strategy to promote the recovery of ischemic stroke is reducing neuronal damage and enhancing neuronal repair. Epoxyeicosatrienoic acids is an intermediate product in which arachidonic acid is metabolized through the cytochrome P450 epoxygenases. Our previous studies have shown that EET can reduce ischemia/reperfusion induced neuronal apoptosis and cerebral infarct volume through mitochondrial biogenesis, facilitate dendritic spine formation. Mitochondrial biogenesis is closely related to mitochondrial dynamic balance, which provide energy for neuronal dendritic growth, dendritic spine and synaptic formation and neural function. However, the mechanism of EET regulating mitochondrial dynamics on neuronal recovery after cerebral ischemia/reperfusion is not clear.This study is intended to investigate EET regulates mitochondrial dynamics for neuronal recovery after cerebral ischemia/reperfusion, such as Mitofusin 2 (Mfn2), dynamin-related protein 1 (Drp1),and further elucidate the signal pathway , expression changes and posttranslational modification.The finding will provide new ideas for development drug for patients with ischemic stroke based nerve repair.

缺血再灌注神经元损伤是缺血性脑卒中重要病理过程，降低神经损伤和促进修复是重要策略。环氧化二十碳三烯酸（EET）是体内花生四烯酸代谢的中间产物。前期研究已证明：EET通过促进线粒体生成降低脑缺血再灌注诱导的神经元凋亡和脑梗死体积，促进树突棘形成。已知线粒体生成与动力学平衡密切相关，线粒体动力学平衡维护线粒体功能，为神经元树突生长、树突棘和突触形成以及神经功能提供能量保障。但EET对脑缺血再灌注后神经元恢复效应中线粒体动力学的调控及机制尚不清楚。本项目拟研究EET调控线粒体融合蛋白（Mfn2），动力相关蛋白（DRP1）等线粒体动力学蛋白的信号通路、表达变化、翻译后修饰，弄清EET对脑缺血再灌注后神经元修复效应中线粒体动力学的调控机制，为研发基于神经修复为策略的治疗药物提供新的思路。

缺血性脑卒中是脑血管疾病患者死亡的最大病因，溶栓治疗和促进神经功能修复是防治该病的两大策略。线粒体是神经元内占比重最多的细胞器。神经元内线粒体分裂和融合的动力学平衡维护线粒体功能，并为神经元的正常功能提供能量保障。本课题以体内体外脑缺血再灌注模型为研究对象，采用透射电子显微镜、免疫荧光、实时定量PCR等实验技术，一方面，证明14,15-EET通过上调抗氧化基因GSH-Px、 HO-1和SOD的转录降解脑缺血再灌注诱导的活性氧，阻止AIF从线粒体移位到细胞核，抑制脑缺血再灌注诱导神经元PARP-1依赖性的细胞凋亡。另一方面，证明14,15-EET通过AMPK/SIRT1/ FoxO1信号通路调控线粒体融合蛋白MFN1/2、 OPA1、线粒体分裂蛋白Fis 1参与的线粒体动力学过程，促进线粒体自噬和稳态，维护神经元结构完整、促进树突棘形成，增强脑缺血再灌注后神经功能恢复。该研究结果为研发基于线粒体为靶标的脑缺血再灌注后神经功能修复药物提供新的思路。