Miro1介导的线粒体动力学对心肺复苏后神经元保护作用及机制研究

Cardiopulmonary resuscitation (CPR) leads to severe impairment of neurological functions, and there is still no effective prevention and therapy strategy. Our previous studies suggested that apoptosis and necrosis of neurons induced by mitochondrial damage was the core mechanism of neurological dysfunction after CPR. Therefore, regulation of mitochondrial dynamic to improve mitochondrial function is of vital importance to restore neuronal physiological function after CPR. Most mitochondria of neurons were severely damaged after CPR. Based on an overall consideration of mitochondrial dynamic, both exogenous mitochondrial transfer and endogenous damaged mitochondrial autophagy clearance are essential, and these two factors are reciprocal and indispensable. Our preliminary experiments have confirmed that mitochondrial Rho GTPase 1(Miro1) served as a core cross-regulatory protein for mitochondrial transfer and mitophagy. Miro1 regulates mitochondrial transfer efficiency. Ubiquitination of Miro1 as a substrate is also the key step in promoting mitophagy. Thus, we hypothesized that Miro1-mediated mitochondrial transfer and mitophagy can regulate mitochondrial dynamic and play a protective role in neurons after CPR. Our topic gets rid of traditional limitation of mitochondrial single-function protection and studies on mitochondrial dynamics as a whole innovatively. Our project will focus on Miro1 as a new target and observe the effects of Miro1-mediated mitochondrial dynamic after CPR on mitochondrial function and hippocampal neuronal outcome in vivo and in vitro. Our investigation could offer a novel perspective and therapeutic strategy for the neurological protection after CPR.

心肺复苏后神经功能严重受损，仍缺乏有效防治策略。我们前期研究显示，线粒体损伤所致神经元凋亡、坏死是心肺复苏后神经功能损伤的核心机制。调控线粒体动力学以恢复线粒体功能，是改善心肺复苏后神经元转归的关键措施，尚缺乏深入研究。心肺复苏后线粒体严重受损，从线粒体动力学整体考虑，外源性健康线粒体转入及原有受损线粒体内源性自噬清除至关重要。我们预实验证实，Miro1是线粒体转移及线粒体自噬的交叉核心调控蛋白。Miro1可调节线粒体转移效率，其泛素化又促发线粒体自噬。我们推测，Miro1介导的线粒体转移及线粒体自噬可协同促进心肺复苏后线粒体功能恢复，发挥神经元保护作用。本课题从线粒体动力学整体出发，聚焦Miro1为新靶点研究其对线粒体转移、自噬的介导机制；继而在细胞及大鼠层面探索Miro1介导的线粒体动力学对心肺复苏后线粒体功能及神经元的保护作用，为心肺复苏后神经功能保护提供新的理论基础和实验依据。

背景：线粒体治疗已成为缺血性疾病的一个热门研究方向。既往有研究报道了线粒体移植在局灶性脑缺血再灌注损伤中的应用，但外源性线粒体移植是否可应用于心脏骤停引起的全脑缺血再灌注损伤尚不清楚。方法：我们假设外源性线粒体移植可以减少心脏骤停后神经元凋亡，减轻神经功能损伤程度。建立大鼠心肺复苏模型，通过尾静脉注射外源性线粒体，观察大鼠心肺复苏后行为学评分、凋亡蛋白表达水平、脑组织氧化应激水平、神经元凋亡水平以及线粒体膜通透性转化孔通道开放水平等。结果：我们的研究结果表明，线粒体移植可减少心肺复苏后神经系统损伤严重程度，改善神经系统预后。移植的线粒体分布在整个神经元细胞中，并降低了氧化应激。线粒体灌注可下调凋亡蛋白表达水平，减少缺血/再灌注损伤诱导的神经元细胞凋亡，并抑制存活神经元细胞线粒体通透性转化孔通道（MPTP）的开放。结论：外源性线粒体移植可减少神经元细胞的缺血/再灌注损伤，降低神经元凋亡率，从而改善心脏骤停引起的神经功能损伤。