Aβ损伤致PC12细胞AD模型PS1介导的自噬功能研究

发布时间：2018-03-03 23:37

本文选题：β淀粉样蛋白　切入点：自噬　出处：《吉林大学》2017年博士论文　论文类型：学位论文

【摘要】：阿尔茨海默病(Alzheimer disease,AD)是老年痴呆的主要类型,是一种进行性发展的慢性致死性神经系统退行性疾病,随着社会老龄化的日益严重,已经成为威胁人类健康的第四大杀手,其早诊断、早预防、早治疗是目前全社会关注的焦点问题。β淀粉样蛋白(β-Amyloid,Aβ)可能是各种原因诱发AD形成和发展的关键因素,Aβ42与Aβ40是体内长链β淀粉样蛋白的主要成分,Aβ42较Aβ40疏水性强,有极高的神经毒性及自我聚集活性,形成不可溶的Aβ纤维体导致老年斑的形成,引起神经元突触的肿胀,功能丧失,最终导致神经元功能障碍致细胞死亡。目前认为,可溶性Aβ寡聚体是产生神经毒性作用的重要来源,比纤维状Aβ毒性更强。但体内可溶性Aβ很难获得,创造其在体内的聚集环境很难实现,但体外分析其变化的动态特征可以实现。自噬是清除异常沉积的β淀粉样蛋白的主要途径,其在阿尔茨海默病疾病的不同时期担任了不同的角色。早老素1(Preselin1,PS1)为调节β淀粉样蛋白生成的关键酶γ分泌酶的主要成分,是溶酶体酸化的关键蛋白。目前的研究结果表明β淀粉样蛋白、PS1及自噬在阿尔茨海默病发生发展过程中所起的作用不尽相同,可能相互影响,机制尚不完全清楚。本研究应用可溶性的Aβ寡聚体诱导PC12细胞制备AD的细胞模型,体外分析Aβ42动态变化时PC12细胞凋亡的发生,PS1、自噬相关蛋白Beclin1、p62的变化及相互关系,可能干预的靶点进行了研究,得出以下结论:(1)Aβ诱导的细胞自噬与Aβ混合物Aβ42/Aβ40的比值显著相关,呈剂量依赖性,可以作为AD早期阶段的研究指标;(2)在一定的浓度范围内,Aβ42诱导细胞自噬的同时不增加细胞毒性,不增加细胞凋亡,为干预AD发生发展的最佳阶段;(3)Aβ42诱导Aβ蛋白的异常沉积与PS1的表达量无关,与其结构及功能异常相关;(4)Aβ42诱导自噬的激活PS1介导的自噬溶酶体清除障碍有关,可以成为AD早期治疗的靶点。
[Abstract]:Alzheimer's disease (AD) is a major type of Alzheimer's disease. It is a progressive, chronic and fatal neurodegenerative disease. With the aging of society, it has become a major killer of human health. Its early diagnosis, early prevention, Early treatment is the focus of the whole society. 尾 -amyloid protein (尾 -Amyloido A 尾) may be the key factor to induce the formation and development of AD. A 尾 42 and A 尾 40 are the main components of amyloid amyloid protein, A 尾 42 is stronger than A 尾 40 in hydrophobicity. It has extremely high neurotoxicity and self-aggregation activity, and the formation of insoluble A 尾 -fiber body leads to the formation of senile plaques, the swelling of synapses, the loss of function of neurons, and the eventual death of cells due to neuronal dysfunction. Soluble A 尾 oligomers are an important source of neurotoxic effects, and are more toxic than fibrous A 尾, but soluble A 尾 in vivo is difficult to obtain and to create an accumulation environment in the body. But in vitro analysis of its dynamic characteristics can be realized. Autophagy is the main way to clear the abnormal deposition of 尾 -amyloid protein. It plays different roles in different stages of Alzheimer's disease. Preselin 1PS1 is the main component of the key enzyme 纬 -secretory enzyme regulating the production of 尾 -amyloid protein (尾 -amyloid). It is the key protein of lysosomal acidification. The current research results show that 尾 -amyloid PS1 and autophagy play different roles in the development of Alzheimer's disease, and may interact with each other. The mechanism is not completely clear. In this study, PC12 cells were induced by soluble A 尾 oligodeoxynucleotides (A 尾 -oligodeoxynucleotides). In vitro, the changes of apoptosis of PC12 cells and the changes of autophagy associated protein Beclin1p62 were analyzed in vitro. The possible targets of intervention were studied. It was concluded that the ratio of A 尾 42 / A 尾 40 to A 尾 4 2 / A 尾 40 was significantly correlated with the ratio of A 尾 42 / A 尾 40 in a dose-dependent manner. It can be used as an early stage study index of AD. It can be used to induce autophagy without increasing cytotoxicity and apoptosis in certain concentration range of A 尾 42. In order to interfere with the optimal stage of AD occurrence and development, the abnormal deposition of A 尾 protein induced by A 尾 42 was not related to the expression of PS1, but related to the dysfunction of lysosomal clearance mediated by PS1 induced autophagy activated by PS1. It can be a target for early treatment of AD.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R749.16

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