BAG-1/HSP70相互作用在脑缺血神经元凋亡中的保护作用及分子机制研究

BAG1 (Bcl-2-associated athanogene-1) was originally discovered as a Bcl-2-binding protein with antiapoptotic activity. Accumulating evidence has demonstrated the antiapoptotic activity of BAG1 on tumor cells. However, little is known about the mechanisms underlying the protective effect of BAG1 against cerebral ischemia. Our previous results demonstrated that the exogenous expression of HSP70 alleviated the injury of neurons in cerebral ischemia. In this study, we will further investigate the protective effect of exogenous BAG1 expression on cerebral ischemia-induced apoptosis in primary cultured neurons, stroke animal models and Bag-1−/− rats and elucidate the possible mechanisms. We hypothesize that BAG1 could exert its antiapoptotic activity to protect against cerebral ischemia through combining with HSP70. The antiapoptotic mechanisms of BAG1/HSP70 might be related to the inhibition of endoplasmic reticulum calcium release and calcium-induced apoptosis by regulating memebers of BCL-2 family and increasing the phosphorylation of BAD via regulating subcellular distribution of Akt and Raf. To clarify the molecular mechanisms underlying the antiapoptotic activity of BAG1/HSP70 in cerebral ischemia provide new research results and strategies to the development of drugs for the prevention and treatment of cerebral ischemia.

BCL-2结合抗凋亡基因BAG1的抗凋亡作用已有文献报道，但目前对BAG-1的研究多集中于其在肿瘤细胞凋亡中的作用，BAG1在脑缺血损伤神经元凋亡中的作用及分子机制尚不清楚。本课题组前期实验结果表明外源性热休克蛋白HSP70表达可保护神经元缺氧损伤，故本研究拟在前期研究基础上应用多种技术方法进一步探讨BAG1/HSP70在脑缺血损伤神经元凋亡中的保护作用，并深入研究其保护作用的分子机制。证实BAG1可通过与HSP70协同作用保护脑缺血损伤诱发的神经元凋亡，其抗凋亡机制可能与调控BCL-2家族，抑制内质网钙释放以及调控Akt和Raf在线粒体的定位，进而增强BAD的磷酸化有关。阐明其在脑缺血损伤中的抗凋亡分子机制有助于针对BAG1与HSP70/Hsc70结合的位点开发保护脑缺血损伤神经元的药物，为临床上治疗缺血性脑血管疾病提供新的思路。

Bcl-2结合抗凋亡基因BAG1的抗凋亡作用已有文献报道，但目前对BAG-1的研究多集中于其在肿瘤细胞凋亡中的作用，BAG1在脑缺血损伤神经元凋亡中的作用及分子机制尚不清楚。本课题组前期实验结果表明外源性热休克蛋白HSP70表达可保护神经元缺氧损伤，本研究在原代培养的大鼠皮层神经元，人神经母细胞瘤细胞系SH-SY5Y细胞，局灶脑缺血再灌注大鼠模型，应用Western blot、实时荧光定量PCR、慢病毒构建、基因干扰、流式细胞仪、激光共聚焦显微镜等多种技术方法，证实了BAG-1与HSP70的相互作用能够保护脑缺血损伤神经元的凋亡，其抗凋亡的机制可能与调控BCL-2家族，抑制内质网钙释放以及PI3K/Akt和Ras/Raf/MAPK通路有关，为临床上治疗脑血管疾病提供新的思路，也为阐明应激后脑组织抗损伤作用机制提供实验依据。

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