MicroRNA调控BACE1在AD发病中的作用与机制研究

项目名称： MicroRNA调控BACE1在AD发病中的作用与机制研究

项目编号： No.81471284

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： 彭国平

作者单位： 浙江大学

项目金额： 70万元

中文摘要： 表观遗传调控在阿尔茨海默病（AD）发病中的作用与机制受到重视。我们的前期工作发现：miR-338-5p在转基因AD小鼠及AD患者脑组织中显著低表达，其能与β位淀粉样前体蛋白裂解酶1（BACE1）的3'非编码区特异性结合；细胞水平初步证实miR-338-5p抑制BACE1的蛋白表达。BACE1是产生Aβ多肽并启动AD病理级联的关键限速酶，由此提示miR-338-5p的下调在AD发病中起重要作用。基因分析发现miR-338-5p基因的启动子区含有炎症转录因子NF-κB的结合位点。因此，本课题拟采用5XFAD转基因小鼠和原代培养神经元模型，通过表观遗传学、分子生物学、组织病理学、电生理及行为学等技术，探索NF-κB调控miR-338-5p转录表达的分子机制，并进一步阐明miR-338-5p对BACE1表达的调控效应及其在AD发病中的作用。本课题将为AD发病机制及防治靶标的研究提供新的理论基础。

中文关键词： 阿尔茨海默病；β-淀粉样蛋白；微小RNA；β位淀粉样前体蛋白裂解酶1；核转录因子κB

英文摘要： The role and mechanism of epigenetic regulation in AD pathogenesis have received increasing attention recently. Our previous work showed that, the expression of miR-338-5p in the hippocampal brain tissue was significantly decreased, while the protein expression level of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) was markedly increased, in both transgenic 5XFAD mice and AD patients. By target gene analysis and fluorescence report vector expression, we confirmed the specific binding of miR-338-5p and 3' untranslated region of BACE1 mRNA. Cellular experiments preliminary confirmed that miR-338-5p upregulation could inhibit the protein expression levels of BACE1. BACE1 is a key rate-limiting enzyme in the procedure of amyloid precursor protein (APP) cleaving to produce Aβ polypeptide and starting the cascade of AD pathological injury. Thus, we assume the decreased expression of miR-338-5p palyed an important role in the pathogenesis of AD. Meanwhile, gene sequence analysis suggests there are two bindig motifs of nuclear transcription factor-B (NF-κB) in the promoter of miR-338-5p gene. Therefore, we suppose the neuroinflammation in the AD process could induce the NF-κB activation and then cause the inhibition of miR-338-5p transcription, and thus lead to the increased BACE1 protein and Aβ production, also the aggravation of AD pathology. To confirm this hypothesis, we intend to use 5XFAD transgenic mice and primary cultured neurons as the study model, aslo by using technical means such as molecular biology, tissue pathology, electrophysiological and behavioral tests, to explore the molecular mechanism of NF-κB regulation on miR-338-5p transcriptional expression, and to further clarify the post-transcriptional regulation of miR-338-5p on BACE1 and its role in the pathogenesis of AD. This study will provide a new theoretical basis on the AD pathogenesis, and also molecular targets for AD prevention and treatment.

英文关键词： Alzheimer's diseases;Amyloid peptide;microRNA;BACE1;NF-κB