ATF6通路活化对心搏骤停后脑功能的保护作用及机制研究

Cardiac arrest is the common disease and the leading cause of death. Although the cadio-pulmonary resuscitation techniques are becoming widespread and much progress have achieved in primary CPR, the in-hospital mortality and neurological disabilities remain high level in CA patients. However, effective medication is still absent in clinic. So the research on the mechanisms and exploring novel medication of brain injury after CA is very important. Unfolded protein response(UPR) is an cellular self adaptative response to endoplasmic reticulum stress. We found that activation of ATF6 can reduce infarction volume and recover the neurological function in MACO mice. Then what’s the function of activation of ATF6 branch of UPR in the brain post CA? It remains to be clarified till now. So, we try to study the possible protective effects on brains using tamoxifen-inducing over expression of ATF6 in ATF6-KI mouse CA/CPR models. Firstly, we will study the pathological changes in cortex and hippocampus, the cerebral function, the cellular autophagy and the changes in each signaling pathways of UPR. Furthermore, we will test and verify the neuron protection and its mechanisms of activation of ATF6 by using genetic overexpression technique at cellular level. The aim of this study is to clarify the neuroprotective roles of activating ATF6 pathway of the UPR and its mechanisms post cardiac arrest, and to provide experimental and theoretical evidences for exploring novel therapeutic drugs.

心搏骤停（CA）是临床常见急症和主要死因。随着心肺复苏技术的普及，初级复苏成功率明显提高，但CA患者住院死亡率和脑功能障碍居高不下。目前临床缺乏有效促进脑复苏的药物。因此，研究CA后脑功能损伤机制及保护措施具有重要意义。未折叠蛋白反应（UPR）是细胞对内质网应激的适应性反应。我们前期研究发现，UPR的ATF6信号通路活化能缩小脑缺血小鼠的脑梗死面积，保护脑功能。那么，ATF6通路活化对CA后的脑功能是否具有保护作用呢？迄今，尚未见相关的系统研究报道。为此，我们将利用ATF6-KI转基因小鼠，研究ATF6活化对CA后神经功能、大脑皮层和海马组织结构、细胞自噬及对UPR各信号通路的影响；进一步结合基因过表达技术，在细胞水平验证ATF6通路活化对缺血再灌注神经细胞的保护作用及机制。本研究旨在阐明ATF6通路活化对CA后脑功能的保护作用及其机制，为开发新的CA后脑损伤治疗药物提供实验和理论依据。

心搏骤停（CA）是临床常见急症和主要死因，然而，目前临床缺乏有效促进脑复苏的药物。因此，研究CA后脑功能损伤机制及保护措施具有重要意义。结合我们的前期研究，即未折叠蛋白反应（UPR）是细胞对内质网应激的适应性反应，而UPR的ATF6信号通路活化能缩小脑缺血小鼠的脑梗死面积，保护脑功能，我们设计并实施了本课题。我们在动物和细胞水平层面上发现ATF6通路激活具有脑保护作用，表现为基因过表达或激动剂干预组动物死亡率的减低和神经功能的改善，以及激动剂干预后细胞活性的增强。进一步研究发现，激活ATF6通路能够通过促进与内质网内蛋白折叠相关的分子伴侣如GRP78等的表达来缓解内质网应激促进细胞存活，抑制细胞凋亡，减轻氧化应激。ATF6通路与其他UPR通路的交互作用及其在CA后脑损伤中的作用也尚未可知，我们也做了相关实验。总之，本研究初步阐明了ATF6通路活化对CA后脑功能的保护作用及其机制，为阐明CA后脑损伤的内源性保护机制、开发新的CA后脑损伤治疗靶点提供了实验和理论依据。在项目实施过程中，囿于小鼠CA模型的稳定性及具体的实验条件的限制，课题组进行了大鼠CA电刺激模型和窒息模型的对比研究，以及通过ATF6激动剂AA147和IRE1抑制剂4μ8c对HT22细胞的作用，来探讨ATF6通路和IRE1-xbp1通路的交互作用。