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)是一种常见的、破坏性的疾病，并造成巨大的社会和经济负担。目前，还没有有效的治疗阿尔茨海默病的方法可用或迫在眉睫，部分原因是我们缺乏对疾病期间人类神经元和神经胶质细胞失效的细胞机制和途径的完全了解，部分原因是我们没有充分了解常见的遗传变异是如何改变人类神经元和胶质细胞表型的。在这里，我们建议测试在人类诱导多能干细胞(HiPSC)的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，然后调查GWAS研究确定的候选基因集在被自然发生的变异减少、增加或改变时产生类似表型的程度。为了解决这两个问题，我们提出了独特的应用HiPSC技术来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危险因素如何易患SAD在人类神经元和星形胶质细胞中的生化表型。在可能的情况下，我们会将体外信息与个别患者的临床数据和加州大学圣迭戈分校ADRC的尸检病理联系起来。对SAD患者的HiPSC系的分析对于探索常见的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，也将初步估计导致SAD患者和对照的基因组频率导致相关SAD表型在体外分化的神经细胞。这一频率估计将有助于解决重要的长期问题，即是否可以使用HiPSC系来预测特定个体患SAD的可能性，即产生SAD的预测性基因组/HiPSC诊断。这项建议利用了我们和其他人之前的工作，分析了携带APPDP重复(APPDP)或21三体的患者的HiPSC线。这两种情况似乎都是通过在原本为整倍体的基因组中增加50%的APP表达而导致FAD。从这些HiPSC系获得的神经元表现出典型的AD生化变化，包括A？升高，GSK3活性升高，以及在所建议的病理部位tau蛋白磷酸化水平升高。我们还发现，APPV717F而不是PS1dE9突变会导致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，这增加了利用HiPSC技术研究早期致病途径的可能性。我们还发现，HiPSC的研究可以阐明一种常见的遗传风险因子SORL1如何在人类神经元中发挥作用。因此，我们提出了三个具体目标：1)测试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，从而导致AD典型的下游生化病理的假设。2)测试假设，即在GWAS研究中被确定为危险因素的基因产生AD表型，并在表达过高或过低时改变内吞、运输或运输。3)验证这样一种假设，即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。