A novel human 3D neural cell culture system for the characterization of AD genes

描述（由申请人提供）：最近的全基因组关联研究（GWAS）和全基因组测序（WGS）分别成功鉴定了新的阿尔茨海默病（AD）相关风险基因及其功能变体。我们最近的大规模WGS努力（阿尔茨海默氏症基因组计划，AGP-WGS; N = 1510个样本）已经确定了几十个功能性遗传变异，与家族性AD紧密共分离。AD风险基因及其功能变异对揭示AD的致病机制具有重要意义，并为AD的预防和治疗提供了新的药物靶点。主要的挑战是现在充分表征AD连锁功能变体的致病作用。迄今为止，该领域缺乏一个单一的疾病模型系统，完全概括了人类神经系统中AD的致病级联。在初步研究中，我们描述了一种新的人类干细胞衍生的3D神经细胞培养模型的创建，其中淀粉样蛋白-β前体蛋白（APP）和早老素1（PSEN 1）中的家族性AD突变诱导细胞外β-淀粉样蛋白积聚，也导致神经元缠结。因此，使用这种独特的模型系统，我们首次表明β-淀粉样蛋白沉积足以诱导强烈的tau蛋白病，包括人类神经细胞系统中的过度磷酸化tau蛋白和洗涤剂抗性、银阳性神经元缠结。以前没有小鼠模型在不共表达Aβ和tau相关基因突变的情况下实现这一点。我们现在提出以下目标，采用我们的新的3D人类神经细胞培养模型来全面评估新的AD基因及其功能变体对AD发病机制的影响。在目标1中，我们将使用我们独特的人类3D神经细胞模型系统，研究AD风险基因及其功能性遗传变体（鉴定为B AGP-WGS）对β-淀粉样蛋白和tau病理的影响。在目标2中，我们将探索在人类3D神经细胞模型系统中过量β-淀粉样蛋白沉积诱导的基因表达和蛋白质组学谱的变化。还将探索AD风险基因/功能变体与过量β-淀粉样蛋白触发的分子途径之间的潜在相互作用。拟议研究的总体目标是构建一个框架，使用我们的新型人类3D神经细胞培养技术系统地识别和表征GWAS/WGS AD风险基因及其功能变体。我们的研究不仅可以加深我们对AD病因和病理的理解，而且有助于发现新的AD药物靶点，用于治疗和预防AD。

DESCRIPTION (provided by applicant): Recent genome-wide association studies (GWAS) and whole genome sequencing (WGS) have been successful in identifying novel Alzheimer's disease (AD)-associated risk genes and their functional variants, respectively. Our recent large-scale WGS efforts (Alzheimer's Genome Project, AGP-WGS; N = 1510 samples) have identified dozens of functional genetic variants that tightly co-segregate with familial AD. AD risk genes and their functional variants carry significant potential for unraveling the pathogenic mechanisms underlying AD, as well as provide new drug targets for the prevention and treatment of AD. The major challenge is to now fully characterize the pathogenic effects of AD-linked functional variants. To date, the field has lacked a single disease model system that fully recapitulates the pathogenic cascade of AD in a human neural system. In preliminary studies, we describe the creation of a novel human stem cell-derived 3D neural cell culture model in which familial AD mutations in the amyloid-β precursor protein (APP) and presenilin 1 (PSEN1) that induce extracellular β-amyloid accumulation, also leads to neurofibrillary tangles. Thus, using this unique model system, we show for the first time that β-amyloid deposition is sufficient to induce robust tauopathy, including hyperphosphorylated tau and detergent-resistant, silver-positive neurofibrillary tangles in a human neural cell system. No mouse model has previously achieved this without co-expressing both Aβ- and tau-related gene mutations. We now propose the following aims to employ our novel 3D human neural cell culture model to comprehensively assess novel AD genes and their functional variants for effects on AD pathogenesis. In Aim 1, we will investigate the impact of AD-risk genes and their functional genetic variants, identified b AGP-WGS, on β-amyloid and tau pathologies, using our unique human 3D neural cell model system. In Aim 2, we will explore changes in gene expression and proteomic profile induced by excess β-amyloid deposition in the human 3D neural cell model system. Potential interactions between AD risk genes/functional variants and molecular pathways triggered by excess β-amyloid will also be explored. The overarching goal of the proposed studies is to construct a framework for systematically identifying and characterizing GWAS/WGS AD risk genes and their functional variants using our novel human 3D neural cell culture technology. Our studies should not only enhance our understanding of the etiology and pathology of AD, but also facilitate the discovery of novel AD drug targets for the treatment and prevention of AD.