ATM蛋白介导药物性预适应在缺血性脑损伤中的作用及机制研究

Cerebral ischemic preconditioning is the strongest endogenous protective phenomenon discovered to date in ischemic brain damage, but its mechanism is still in nubibus. Recent studies showed that ATM (ataxia telangiectasia mutated) protein is the linchpin of cellular defenses to stress. ATM deletion can induce strong oxidative stress and degenerative diseases in the nervous system. In preliminary experiments, we observed that cerebral ischemia preconditioning could activate the ATM protein immediately and up-regulate ATM protein expression. However, treatment with ATM protein specific inhibitor to the mouse neuronal tumor cells could inhibit the protective effect of pretreatment with H2O2. Therefore, we hypothesize that the ATM protein may be involved in cerebral ischemic preconditioning effect. This project intends to establish the model of rat cerebral ischemic preconditioning and oxygen and glucose deprivation preconditioning of primary cultured neurons, and confirm the role of ATM protein as the endogenous protein in brain ischemic preconditioning with ATM inhibitors and ATM RNA interference techniques in whole-body and cell level. On these basis, we will further explore whether pretreatment of chloroquine, an ATM protein activator, can protect from ischmic brain injury and the underlying mechanisms. This study will provide the possibility of the ATM protein as a key target of pharmacological preconditioning, and a novel insight for the drug of prevention and treatment of ischemic brain damage.

脑缺血预适应是迄今为止发现的对缺血性脑损伤最强的神经内源性保护现象，但发生机制仍然不明。目前研究认为ATM(ataxia telangiectasia mutated)蛋白是细胞防御各种应激的枢纽。ATM缺失可引起神经系统氧化应激及退行性病变。前期研究中我们观察到：大鼠脑缺血预处理可即时激活ATM蛋白并使ATM蛋白表达水平增加，并利用ATM蛋白特异抑制剂作用于小鼠神经元瘤细胞，能够抑制H2O2预处理的保护效应，因此推测ATM蛋白可能参与了脑缺血预适应过程。本课题拟建立大鼠脑缺血预适应和原代神经细胞缺糖缺氧预适应模型，在整体和细胞水平运用ATM蛋白抑制剂、RNA干扰等方法确证ATM 蛋白作为内源性蛋白在脑缺血预适应中的作用地位；并利用ATM蛋白激活剂氯喹预处理，探讨其对大鼠缺血性脑损伤的保护效应与相关机制，旨在解析ATM蛋白作为药物性预适应关键靶点的可能性，为缺血性脑损伤预防用药开辟新思路。

脑缺血预适应是迄今为止发现的对缺血性脑损伤最强的神经内源性保护现象，但发生机制仍然不明。本课题利用小鼠脑缺血预适应和原代神经细胞缺糖缺氧预适应模型，在整体和细胞水平运用ATM蛋白抑制剂、RNA干扰以及多种分子生物学方法明确了胞浆中的ATM蛋白参与了脑缺血预适应效应；在细胞水平明确了ATM蛋白激活剂氯喹预处理对神经元OGD损伤具有保护作用；同时在细胞水平发现了在致命性的OGD损伤过程中，持续性抑制ATM蛋白活性，或在致命性的OGD损伤前抑制ATM蛋白的表达，能抑制神经元的凋亡，表明ATM蛋白可能参与了致命性的OGD损伤所引进的神经元凋亡。本项研究解析了ATM蛋白作为药物性预适应关键靶点的可能性，为缺血性脑损伤防治用药开辟新思路。