朊病毒感染激活自噬的分子机制研究

项目名称： 朊病毒感染激活自噬的分子机制研究

项目编号： No.81472004

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 医药、卫生

项目作者： 田婵

作者单位： 北京大学

项目金额： 80万元

中文摘要： 朊病毒病是一类感染人及多种动物的致死性神经退行性疾病，由朊蛋白的错误折叠或突变引起。细胞自噬是真核细胞用于清除胞内聚集物、受损细胞器、适应营养缺乏、环境胁迫等维持细胞稳态平衡的一种蛋白质降解过程。本课题组前期研究的结果显示朊病毒感染后自噬活化，且是通过mTOR下调引起。本研究旨在从体内、体外两个层面研究朊病毒感染后其他自噬调节通路：AMPK直接调节ULK1引发自噬的通路、DAPK调节的信号通路以及NF1调节的自噬通路上各分子及其活性的磷酸化形式蛋白表达水平的变化，然后通过在感染动物潜伏期内的不同时间点动态观察这些分子的变化过程，并与PrPSc沉积、神经元丢失等病理变化相结合，最后通过在细胞模型上敲降或过表达关键分子，检测细胞自噬情况，来反向证实这些信号通路在朊病毒感染中的作用，进一步揭示感染后自噬激活的分子机制，为在更广阔范围内寻找治疗朊病毒病的潜在治疗方法奠定基础。

中文关键词： 朊病毒；自噬；机制；信号通路

英文摘要： Prion diseases are known as a group of fatal neurodegenerative disorders, which affect both human and mammalian animals. It is widely accepted that prion diseases are caused by mifolding of a host-encoded glycoprotein PrPC into PrPSc as well as the mutation happened on PRNP gene. Autophagy is a critical cellular process involves degradation and digestion of cytoplasmic content, organelles and misfolded proteins by lysosomes. We have reported that autophagic flux was activated in 263K-infected hamsters and human genetic prion diseases, and the down-regulation of mTOR was mainly responsible for it. In this study, we aim to research if prion infection could activate other autophagy regulation pathways, like AMPK-ULK1, DAPK signaling pathway and NF1-regualted pathways. We will detect the protein expression levels of the molecules in these pathways and their phosphorylated forms in brain tissues from hamsters, mice and human infected with prion diseases. We also will test their expression level in chronic prion-infected cell lines. The dynamic changes of these molecules and their active forms, as well as the neuropathologic damages will be observed in the incubation period. Then we will reverse the expression of the key factor of each pathway by knock-down or over-expression to see if autophagy could be prohibited. All together, we could understand the role of these pathways in prion infection and neuropahtologic damages. It will be very helpful to explore the potential therapeutic method to treat prion diseases.

英文关键词： prion;autophagy;mechanism;signaling pathway