Role of Ataxin-1 in BACE1 Expression and Alzheimer's Disease

Ataxin-1 在 BACE1 表达和阿尔茨海默病中的作用

• 批准号: 9763397
• 负责人: Jaehong Suh
• 金额: $ 41.3万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9763397
• 关键词: Acute; Address; Adult; Affect; Age; Aging; Alzheimer' s Disease; Alzheimer' s disease risk; Amyloid beta-Protein Precursor; Axon; Binding; Binding Proteins; Biochemical; Brain; Brain Diseases; Brain region; CAG repeat; CRISPR/Cas technology; Cell Nucleus; Cells; Cerebrum; Chromatin; Culture Media; DNA; Data; Deposition; Disease; Etiology; Family; Follow-Up Studies; GFI1 gene; Gene Expression; Gene Mutation; Genes; Genetic; Genetic Determinism; Genetic Transcription; Genome; Gliosis; Hippocampus (Brain); Human; Impairment; Individual; Knockout Mice; Mammalian Cell; Measures; Mediating; Messenger RNA; Meta-Analysis; Molecular; Movement; Mus; Mutation; Mutation Analysis; National Institute of Mental Health; Neurodegenerative Disorders; Neurons; Pathogenesis; Pathology; Pathway interactions; Patients; Play; Protein Secretion; Proteins; Proteomics; Protocols documentation; RNA; Recording of previous events; Regulation; Reporting; Research; Risk; Role; Sampling; Senile Plaques; Site; Slice; Testing; Type 1 Spinocerebellar Ataxia; Variant; amyloid precursor protein processing; ataxin-1; base; beta-site APP cleaving enzyme 1; genetic variant; genome sequencing; genome wide association study; inhibitor/antagonist; knock-down; loss of function; neurogenesis; novel; novel therapeutics; nucleotide analog; olfactory bulb; prevent; promoter; secretase; transcription factor; whole genome

Project Summary Recent efforts to uncover genetic factors responsible for Alzheimer's disease (AD) have identified dozens of associated loci. Among these, our research group previously reported ATXN1 in a family-based AD genome-wide association study. ATXN1 has been otherwise known for to harbor mutations causing spinocerebellar ataxia type 1, a neurodegenerative disease that primarily impairs coordinated movement. In a cell-based study, knockdown of Ataxin-1 gene (ATXN1) expression increased amyloidogenic processing of the amyloid precursor protein (APP) and the secretion of A, the main component of senile plaques in AD brains. In the preliminary examination of Ataxin-1 KO mice, we found Ataxin-1 regulates BACE1 expression, selectively in AD-vulnerable brain regions. In AD mice, depletion of Ataxin-1 increased -secretase-cleavage of APP, A deposition and gliosis in the cerebrum. Furthermore, Ataxin-1 KO impaired hippocampal neurogenesis and axonal targeting, which are regulated by BACE1. To validate and expand upon these findings, here, we propose to 1. Elucidate the molecular mechanism by which Ataxin-1 regulates BACE1 expression in the brain; 2. Assess the impact of Ataxin-1 loss of function on AD pathogenesis; and 3. Identify and characterize novel AD-associated Ataxin-1 gene variants and/or mutations from AD DNA sample sets. Specifically, for Aim 1, we will first determine whether Ataxin-1 regulates BACE1 mRNA level by affecting its stability or by its transcription. To test this, we will employ acute brain slice cultures of Ataxin-1 KO and WT mice, and examine the differential effects of transcriptional inhibitors on the steady-state level of BACE1 mRNA and also measure newly synthesized BACE1 mRNA incorporating nucleotide analogs in the cultured slices. We will then examine if Ataxin-1-interacting transcriptional factors bind to and regulate BACE1 promoter by ChIP analysis. With regard to Aim 2, we will examine if the increased A plaque load and gliosis are maintained in APP-PS1/ATXN1-KO mice at older age (9 month). To determine if impaired hippocampal neurogenesis and axonal targeting are caused by increased BACE1, we will generate ATXN1 −/−:BACE1 +/− mice and examine if the two deficits are rescued, as compared to ATXN1 −/− mice. Finally, in Aim 3, we will identify ATXN1 mutations/variants that either increase risk or confer protection for AD by analysis of WGS/WES data of NIMH, NIA and ADNI AD DNA sample sets. For the most associated mutations/variants, we will examine their effects on BACE1 expression and APP processing by incorporating them into the genome of human neuronal cells via CRISPR/Cas9 technology. At the completion of the proposed study, we believe we will provide critically needed data addressing the role of Ataxin-1 in regulating BACE1 expression while also facilitating novel therapies aimed at targeting BACE1 to prevent and treat AD.

项目摘要 最近的努力，以揭示遗传因素负责阿尔茨海默氏病（AD）已确定 几十个相关的基因座其中，我们的研究小组先前报道了ATXN 1在一个以家庭为基础的AD中的表达， 全基因组关联研究ATXN 1已经被认为具有突变， 脊髓小脑共济失调1型，一种主要损害协调运动的神经退行性疾病。中 一项基于细胞的研究表明，Ataxin-1基因（ATXN 1）表达的敲低增加了 淀粉样前体蛋白（APP）和AD脑中老年斑的主要成分A β的分泌。 在对Ataxin-1基因敲除小鼠的初步研究中，我们发现Ataxin-1调节BACE 1的表达， 选择性地在易患AD的大脑区域。在AD小鼠中，Ataxin-1的消耗增加了AD小鼠的β-分泌酶切割。 APP、A β沉积和脑胶质增生。此外，Ataxin-1 KO损害海马 神经发生和轴突靶向，这是由BACE 1调节。为了验证和扩展这些 调查结果，在这里，我们建议1。阐明Ataxin-1调节BACE 1的分子机制 在大脑中的表达; 2。评估共济失调蛋白-1功能丧失对AD发病机制的影响;以及3.识别 并表征来自AD DNA样品集的新的AD相关共济失调蛋白-1基因变体和/或突变。 具体而言，对于目标1，我们将首先确定Ataxin-1是否通过影响其表达来调节BACE 1 mRNA水平。 稳定性或通过其转录。为了测试这一点，我们将使用共济失调蛋白-1 KO和WT的急性脑切片培养物， 小鼠，并检查转录抑制剂对BACE 1 mRNA稳态水平的差异作用 并且还测量在培养的切片中掺入核苷酸类似物的新合成的BACE 1 mRNA。 然后，我们将研究是否Ataxin-1相互作用的转录因子结合并调节BACE 1启动子， ChIP分析。关于目标2，我们将检查增加的A β斑块负荷和神经胶质增生是否是 在老年（9个月）APP-PS1/ATXN 1-KO小鼠中维持。为了确定受损的海马 神经发生和轴突靶向是由增加的BACE 1引起的，我们将产生ATXN 1 −/−：BACE 1 +/− 小鼠，并检查与ATXN 1 −/−小鼠相比，这两种缺陷是否得到挽救。在目标3中，我们将 通过分析以下因素来鉴定增加AD风险或赋予AD保护作用的ATXN 1突变/变体： NIMH、NIA和ADNI AD DNA样品集的WGS/WES数据。对于最相关的突变/变体，我们 将通过将它们整合到BACE 1基因组中来研究它们对BACE 1表达和APP加工的影响。 通过CRISPR/Cas9技术获得人类神经元细胞。在完成拟议的研究后，我们认为， 将为阐明Ataxin-1在调节BACE 1表达中的作用提供急需的数据， 促进旨在靶向BACE 1的新疗法以预防和治疗AD。