Functional dissection of fibronectin type 3 domains of SORL1 in Alzheimers disease associated microglia

阿尔茨海默病患者SORL1纤维连接蛋白3型结构域的功能解剖 疾病相关小胶质细胞 阿尔茨海默病(AD)是一种多因素、复杂的疾病，是导致痴呆的主要原因之一 在老年人中。没有有效的药物治疗选择来预防和 由于对阿尔茨海默病的发病机制缺乏完整的了解而导致AD的治疗。有趣的是， 全基因组关联研究已经证实，大多数AD相关基因座是 在小胶质细胞(常驻巨噬细胞)中高/唯一表达的基因中或其附近发现的 大脑)暗示了这些细胞在疾病进展中的关键作用。SORL1是遗传上的 与迟发性和早发性阿尔茨海默病有关。对死后脑组织的研究表明 阿尔茨海默病患者脑内SORL1水平降低。虽然，在脑细胞中，小胶质细胞显示 SORL1的最高表达，但对该蛋白如何调节小胶质细胞表型知之甚少 在健康和疾病期间。我们的初步数据表明，SORL1的一个特定亚型是 富含小胶质细胞，并通过其FN3结构域与波形调节剂相互作用 复合体(WRC)。WRC正在成为细胞迁移和吞噬反应的关键调节器 因此，可以作为AD相关小胶质细胞表型调整的治疗靶点。在这 应用，我们建议：(1)确定SORL1调控的分子机制 小胶质细胞的功能，如吞噬、趋化和细胞因子的表达；(2)测量SORL- 阿尔茨海默病和非AD脑小胶质细胞中FN3的丰度 个体(ROSMAP)建立FN3丰度与AD相关性状之间的关系； (3)使用我们新开发的CRISPR介导法在SORL1-WRC中识别治疗靶点 饱和诱变方法。 总体而言，通过利用创新的CRISPR-Cas9基因组编辑技术(1和3)和新颖的 基于SRM(选择性反应监测)的定量蛋白质组学和遗传学(2)这个建议 将加速基因发现向分子机制的转变，可以打开新的 阿尔茨海默病新疗法的途径。

Functional dissection of fibronectin type 3 domains of SORL1 in Alzheimer's disease associated microglia Alzheimer's disease (AD) is a multifactorial, complex disease and a leading cause of dementia among aged people. There are no effective pharmacotherapeutic options for prevention and treatment of AD due to lack of complete understanding of disease mechanisms. Interestingly, Genome wide association studies have established that the majority of AD associated loci are found in or near genes that are highly/uniquely expressed in microglia (resident macrophage cells of brain) suggesting the critical role of these cells in disease progression. SORL1 is genetically implicated in late and early onset forms of AD. Studies on postmortem brain tissues have shown reduced levels of SORL1 in AD patient brains. Although, among brain cells microglia show highest expression of SORL1, yet little is known how this protein regulates microglia phenotypes during health and disease. Our preliminary data suggest, that a specific isoform of SORL1 is enriched in microglia and it physically interact through its FN3 domain with WAVE regulator complex (WRC). WRC is emerging as critical regulator of cell migration and phagocytic response hence can serve as therapeutic target for tuning up phenotypes of AD related microglia. In this application, we propose to: (1) determine the molecular mechanism by which SORL1 regulate microglia functions e.g. phagocytosis, chemotaxis, and cytokine expression; (2) Measure SORL- FN3 abundance in AD and non-AD brain microglia from cohorts of deeply characterized individuals (ROSMAP) to establish the relationship among FN3 abundance vs. AD related traits; (3) Identify therapeutic targets within SORL1-WRC using our newly developed CRISPR-mediated saturating mutagenesis approach. Overall, by leveraging innovative CRISPR-Cas9 genome editing technologies (1 & 3) and novel SRM (selected reaction monitoring) based quantitative proteomics and genetics (2) this proposal will accelerate the transition of genetic discoveries to molecular mechanism that can open new avenues for novel therapeutics for AD.