Elucidating AD genotype-phenotype relationships using genetics of human IPS cells

利用人类 IPS 细胞遗传学阐明 AD 基因型-表型关系

• 批准号: 8758050
• 负责人: Lawrence S. Goldstein
• 金额: $ 193.6万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8758050
• 关键词: Address; Alzheimer' s Disease; Astrocytes; Biochemical; Candidate Disease Gene; Cell Line; Cell model; Cells; Clinical Data; Data; Diagnostic; Disease; Disease Pathway; Down Syndrome; Elements; Endocytosis; Event; Exhibits; Frequencies; Gene Expression; Genes; Genetic; Genome; Genomics; Genotype; Heritability; Human; Human Genetics; In Vitro; Individual; Lesion; Light; Link; Modeling; Mutation; Neuroglia; Neurons; Pathology; Pathway interactions; Patients; Phenotype; Play; Population; Research; Risk Factors; Role; Site; Testing; Therapeutic; Variant; Work; cell type; disease phenotype; familial Alzheimer disease; gene function; genetic risk factor; genetic variant; genome wide association study; induced pluripotent stem cell; presenilin; public health relevance; research study; secretase; social; stem cell technology; tau Proteins; tau phosphorylation; therapy development; trafficking

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is common, devastating, and creates enormous social and financial burdens. At present, no effective disease-modifying AD treatment is available or imminent, in part because we lack a complete understanding of the cellular mechanisms and pathways that fail in human neurons and glial cells during disease, and in part because we don't adequately understand how common genetic variants alter human neuronal and glial phenotypes. Here we propose to test whether APP and PS mutations generated in common genetic backgrounds in human induced pluripotent stem cells (hIPSC) generate the same early neuronal phenotypes and then to investigate the extent to which a candidate set of genes identified by GWAS studies generate comparable phenotypes when reduced, increased, or altered by naturally occurring variants. To tackle both problems, we propose unique applications of hIPSC technology to 1) dissect how FAD mutations alter key pathways and then 2) to test how individual genetic background and identified risk factors predispose to SAD biochemical phenotypes in human neurons and astrocytes. Where possible, we will link the in vitro information to clinical data on individual patients and to post-mortem pathology from the UCSD ADRC. The analysis of hIPSC lines from SAD patients will be crucial to probe how common genetic risk factors act in neurons and astrocytes and will also give an initial estimate of the frequency of genomes in SAD patients and controls that cause relevant SAD phenotypes in neural cells differentiated in vitro. This frequency estimate will help address the important long-term question of whether hIPSC lines can be used to predict the likelihood that a given individual will develop SAD, i.e., to generate a predictive genomic/hIPSC diagnostic for SAD. This proposal capitalizes upon previous work from us and others that analyzed hIPSC lines from patients carrying an APP duplication (APPDp) or trisomy 21. Both situations appear to cause FAD by increasing APP expression by 50% in an otherwise euploid genome. Neurons made from these hIPSC lines exhibit typical AD biochemical alterations including elevated A¿, elevated activation of GSK3, and elevated phosphorylation of tau at a proposed pathological site. We also found that APPV717F but not PS1dE9 mutations cause elevated p-tau levels. Thus, early neuronal phenotypes of APP and presenilin mutations might be different raising the possibility that there may be multiple early pathogenic pathways that can be studied using hIPSC technology. We also found that hIPSC studies can elucidate how one common genetic risk factor, SORL1, acts in human neurons. We thus propose three specific aims: 1) Test the hypothesis that APP, PS1, and ¿-secretase mutations trigger the same early events in human neurons and astrocytes leading to downstream biochemical pathology typical of AD. 2) Test the hypothesis that genes identified as risk factors in GWAS studies generate AD phenotypes and altered endocytosis, trafficking, or transport when over or underexpressed. 3) Test the hypothesis that common genetic variants identified in GWAS studies act by altering gene expression in neurons or astrocytes.

描述（由申请人提供）：阿尔茨海默病 (AD) 很常见，具有破坏性，会造成巨大的社会和经济负担。目前，还没有有效的缓解 AD 疾病的治疗方法，部分原因是我们对人类神经元和神经胶质细胞在疾病期间失效的细胞机制和途径缺乏完整的了解，部分原因是我们没有充分了解常见的遗传变异如何改变人类神经元和神经胶质细胞的表型。在这里，我们建议测试人类诱导多能干细胞（hIPSC）共同遗传背景中产生的APP和PS突变是否产生相同的早期神经元表型，然后研究GWAS研究确定的一组候选基因在自然发生的变异减少、增加或改变时产生可比表型的程度。为了解决这两个问题，我们提出了 hIPSC 技术的独特应用：1) 剖析 FAD 突变如何改变关键通路，然后 2) 测试个体遗传背景和已识别的风险因素如何容易导致人类神经元和星形胶质细胞中的 SAD 生化表型。如果可能，我们会将体外信息与个体患者的临床数据以及加州大学圣地亚哥分校 ADRC 的尸检病理学联系起来。对 SAD 患者 hIPSC 系的分析对于探究常见遗传风险因素如何在神经元和星形胶质细胞中发挥作用至关重要，还将对 SAD 患者和对照中导致体外分化的神经细胞中相关 SAD 表型的基因组频率进行初步估计。这种频率估计将有助于解决一个重要的长期问题：hIPSC 系是否可用于预测给定个体发生 SAD 的可能性，即生成 SAD 的预测基因组/hIPSC 诊断。该提案利用了我们和其他人之前的工作，这些工作分析了来自携带 APP 重复 (APPDp) 或 21 三体性的患者的 hIPSC 系。这两种情况似乎都是通过将整倍体基因组中的 APP 表达增加 50% 来导致 FAD。由这些 hIPSC 系制成的神经元表现出典型的 AD 生化改变，包括 A¿ 升高、GSK3 激活升高以及在拟议的病理部位 tau 磷酸化升高。我们还发现 APPV717F 而不是 PS1dE9 突变导致 p-tau 水平升高。因此，APP 和早老素突变的早期神经元表型可能不同，这提高了使用 hIPSC 技术可以研究多种早期致病途径的可能性。我们还发现 hIPSC 研究可以阐明一种常见的遗传风险因子 SORL1 在人类神经元中的作用。因此，我们提出了三个具体目标：1）测试以下假设：APP、PS1 和 ¿-分泌酶突变在人类神经元和星形胶质细胞中触发相同的早期事件，导致 AD 典型的下游生化病理学。 2) 检验以下假设：在 GWAS 研究中被确定为危险因素的基因在过度表达或表达不足时会产生 AD 表型并改变内吞作用、运输或运输。 3) 检验以下假设：GWAS 研究中发现的常见遗传变异通过改变神经元或星形胶质细胞中的基因表达来发挥作用。