Investigation of the Tau Gene Network and Quantitative Alzheimer's Disease Biomarker Phenotypes

Tau 基因网络和定量阿尔茨海默病生物标志物表型的研究

• 批准号: 9335777
• 负责人: Kacie Deters
• 金额: $ 6.83万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9335777
• 关键词: Alzheimer' s Disease; Alzheimer' s disease risk; Amyloid Proteins; Amyloid beta-Protein; Analysis of Variance; Atrophic; Binding Proteins; Biological; Biological Markers; Brain; CRISPR/Cas technology; Candidate Disease Gene; Cell Culture Techniques; Cerebrospinal Fluid; Cognition; Complex; Data; Databases; Dementia; Development; Diagnosis; Disease; Drug Design; Drug Targeting; Early Diagnosis; Early treatment; Enzyme-Linked Immunosorbent Assay; Enzymes; Evaluation; Frequencies; Functional disorder; Gene Expression; Gene Frequency; Genes; Genetic; Genetic Polymorphism; Genetic Variation; Genotype; Goals; Impaired cognition; Investigation; Knowledge; Late Onset Alzheimer Disease; Lead; Linear Regressions; Liquid substance; Literature; MAPT gene; Manuals; Measurement; Memory Loss; Methods; Microtubules; Minor; Modeling; Modification; Molecular; Molecular Target; Mutagenesis; Mutation; Nerve Degeneration; Neurobehavioral Manifestations; Neurodegenerative Disorders; Neurons; Outcome; Participant; Pathologic; Pathology; Patients; Phenotype; Phosphorylation; Proteins; RNA Splicing; Regulation; Reporting; Research; Reverse Transcriptase Polymerase Chain Reaction; Role; Single Nucleotide Polymorphism; TYRP1 gene; Techniques; Testing; Therapeutic; Variant; Work; brain morphology; cerebral atrophy; cognitive performance; cohort; disease phenotype; effective intervention; gene interaction; genetic variant; genome sequencing; gray matter; hyperphosphorylated tau; improved; in vivo; innovation; mild cognitive impairment; neuroimaging; new therapeutic target; novel; novel diagnostics; phenotypic biomarker; protective effect; protein B; risk variant; specific biomarkers; tau Proteins; tau aggregation; tau dysfunction; tau expression; tau mutation; tau phosphorylation; therapeutic target; whole genome

Abstract One of the key hallmarks of Alzheimer’s disease (AD) is intracellular aggregates of hyperphosphorylated tau protein. Mutations in the tau gene, microtubule-associated protein tau (MAPT), result in significant abnormal tau pathology post mortem and are known to be causative for neurodegenerative disorders similar to AD. This suggests tau dysfunction is sufficient to cause neurodegeneration and dementia. Pathological tau protein can undergo abnormal modification that leads to increased phosphorylation, aggregation, and ultimately neurodegeneration. Despite some appreciation of the role of MAPT and tau in AD-like dementias, there is an important knowledge gap regarding the mechanisms by which tau-related genetic factors influence AD pathophysiology and progression. Thus, an in-depth investigation of the gene network responsible for regulating proteins involved in the abnormal processing of tau is warranted to help explain the molecular mechanisms governing tau aggregation and potentially identify novel drug targets. Preliminary data of common MAPT variants has already identified a single nucleotide polymorphism (SNP) associated with cerebrospinal fluid (CSF) total-tau levels, rs117199550 (see Research Plan), in participants diagnosed with AD or mild cognitive impairment (MCI) in the Alzheimer Disease Neuroimaging Initiative (ADNI) cohort. This work will be extended using whole-genome sequencing (WGS) data in ADNI, allowing investigation of low frequency (minor allele frequency < 5%) variants which cannot be identified in SNP studies. I hypothesize that variation in MAPT and other genes in the tau gene network are associated, directly or indirectly, with established biomarkers of AD pathophysiology (grey matter atrophy, cognitive decline, and changes in CSF levels of tau and amyloid- beta) in participants diagnosed with AD or MCI. To achieve these goals, I will investigate the following Aims: [1] Investigate the impact of low frequency MAPT genetic variants on AD biomarkers. MAPT variants will be extracted from WGS data and the impact of these variants on key quantitative AD biomarkers will be examined; [2] Develop a tau gene network using a curated gene list from literature searches and databases. Then, I will determine if common and/or low frequency genetic variation within the tau gene network involved in the pathological processing of tau will have a deleterious or protective effect on AD biomarkers using independent, additive, and interactive associations at the gene and SNP level; [3] Functionally characterize rs117199550 and novel SNPs identified in Aims 1 and 2 using CRISPR/Cas9. RT-PCR analysis will be used to quantify changes in MAPT gene expression and ELISA to quantify changes in tau phosphorylation. Together, the proposed Aims provide a unique investigation of MAPT by combining advanced genetic, statistic, and functional techniques. The results of this study will increase our understanding of how genetic variation in MAPT and the tau gene network contribute to AD pathophysiology and potentially identify novel diagnostic and therapeutic targets, which would have direct implications for early detection and treatment of AD.

摘要 阿尔茨海默病（AD）的关键特征之一是过度磷酸化的tau蛋白的细胞内聚集 蛋白tau基因突变，微管相关蛋白tau（MAPT），导致显著的异常 tau病理学，并且已知是类似于AD的神经退行性疾病的病因。这 表明tau蛋白功能障碍足以导致神经变性和痴呆。病理性tau蛋白可以 经历异常修饰，导致磷酸化增加，聚集，最终 神经变性尽管对MAPT和tau蛋白在AD样痴呆中的作用有一定的认识， 关于tau相关遗传因素影响AD的机制的重要知识缺口 病理生理学和进展。因此，对基因网络的深入研究， 调节tau蛋白异常加工的蛋白质有助于解释 控制tau聚集的机制，并可能识别新的药物靶点。共同的初步数据 MAPT变体已经确定了与脑脊髓炎相关的单核苷酸多态性（SNP）。 诊断为AD或轻度AD的受试者的脑脊液（CSF）总tau水平，rs 117199550（见研究计划） 阿尔茨海默病神经影像学倡议（ADNI）队列中的认知障碍（MCI）。这项工作将 在ADNI中使用全基因组测序（WGS）数据进行扩展，允许调查低频（轻微） 等位基因频率< 5%）在SNP研究中不能鉴定的变体。我假设MAPT的变化 和tau基因网络中的其他基因直接或间接地与以下已建立的生物标志物相关： AD病理生理学（灰质萎缩、认知能力下降以及CSF中tau和淀粉样蛋白水平的变化） β）在诊断为AD或MCI的参与者中。为了实现这些目标，我将研究以下目标：[1] 研究低频MAPT遗传变异对AD生物标志物的影响。MAPT变体将是 从WGS数据中提取，这些变体对关键定量AD生物标志物的影响将 [2]使用文献检索和数据库中的精选基因列表开发tau基因网络。 然后，我将确定是否涉及tau基因网络中的常见和/或低频遗传变异， tau的病理学加工将对AD生物标志物具有有害或保护作用， 在基因和SNP水平上的独立、加性和交互关联; [3] rs 117199550和使用CRISPR/Cas9在目的1和2中鉴定的新型SNP。RT-PCR分析将用于 定量MAPT基因表达的变化和ELISA定量tau磷酸化的变化。我们一起努力， 所提出的目标提供了一个独特的研究MAPT结合先进的遗传，统计， 功能技术。这项研究的结果将增加我们对遗传变异如何在 MAPT和tau基因网络有助于AD病理生理学，并可能鉴定新的诊断和治疗方法。 治疗靶点，这将对AD的早期检测和治疗具有直接意义。