Microglial function of GWAS risk factor BIN1 in Alzheimer's disease pathogenesis and inflammatory signaling

项目总结 BIN1是一种接头蛋白，由晚发性AD的第二个最常见的易感GWAS风险因子编码， 在内吞作用、膜重塑和突触小泡的背景下调节膜动力学 放手。大规模的表达数据集已经报道了BIN1在小胶质细胞中的高水平表达，以及AD-1。 相关的BIN1 SNP被认为通过小胶质细胞特异性增强子改变BIN1的表达。然而， 小胶质细胞BIN1在AD病理生理调控中的确切功能作用(S)尚未被研究 系统地。我们的中心假设是小胶质细胞BIN1在神经炎性疾病中起重要作用 BIN1影响AD病理生理学的信号转导机制。我们的初步研究表明，BIN1的损失 在体外(培养的小胶质细胞)和体内(小胶质细胞特异性的CKO小鼠)的表达严重受损 促炎基因的表达和几种疾病相关小胶质细胞(DAM)基因的上调。 我们的转录图谱表明BIN1是一种动态平衡的小胶质细胞调节因子，在 激活APOE、TREM2和Tyrobp上游以及PU.1和IRF1上游的促炎反应。 BIN1被预测在体外和体内调节小胶质细胞的1型和2型干扰素反应。总而言之， 这些发现为了解小胶质细胞BIN1的功能提供了重要的见解，证明了它在大脑中的意义 炎症反应。本研究的总体目标是进一步探讨BIN1的S在小胶质细胞中的作用。 特别是在AD发病机制的背景下，并获得分子方面的见解。目标1的目标是生成 5XFAD：BIN1 CKO小鼠阐明小胶质细胞BIN1在调节脑淀粉样蛋白负荷中的作用 淀粉样蛋白相关的病理生理学。我们将进行详细的生化、分子和神经病理学研究。 表征和执行神经炎症和DAM转变的转录图谱以了解 BIN1的S在小胶质细胞对淀粉样蛋白病理反应中的作用目的2研究试图产生PS19：BIN1 CKO小鼠 小胶质细胞BIN1功能参与tau病理生理和病理传播的研究 详细的神经病理学和全面的生化、蛋白质组学和分子分析。AIM 3研究 将研究BIN1作为早期炎症信号事件的关键调节因子的机制作用 小胶质细胞。我们将使用不偏不倚和假设驱动的方法来定义小胶质细胞BIN1相互作用组和 阐明BIN1及其结合伙伴如何以上下文相关的方式重组以促进免疫 通过关键的小胶质细胞受体传递信号。这一及时而独特的建议具有很强的创新性。我们的策略是使用 小胶质细胞特异性诱导型BIN1 CKO小鼠代表了体内最直接的严格研究方法 小胶质细胞BIN1如何调节阿尔茨海默病的病理生理，并利用全面的转录组学获得洞察力 蛋白质组学和相互作用组学特征。我们相信，成功完成拟议的 研究将填补我们对BIN1作为负荷风险因素的理解的重大空白，并指导未来的功能 这一主要负荷风险基因调控的分子途径和致病机制的特征。

PROJECT SUMMARY BIN1, an adaptor protein encoded by the second most common susceptibility GWAS risk factor of late-onset AD, regulates membrane dynamics in the context of endocytosis, membrane remodeling, and synaptic vesicle release. Large-scale expression datasets have reported high-level BIN1 expression in microglia, and AD- associated BIN1 SNPs are thought to alter BIN1 expression through a microglia-specific enhancer. However, the precise functional role(s) of microglial BIN1 in regulating AD pathophysiology has not been investigated systematically. Our central hypothesis is that microglial BIN1 plays an essential role in neuroinflammatory signaling through which BIN1 influences AD pathophysiology. Our preliminary studies show that the loss of Bin1 expression in vitro (cultured microglia) and in vivo (microglia-specific cKO mice) profoundly impairs proinflammatory gene expression and the upregulation of several disease-associated microglia (DAM) genes. Our transcriptomic profiling identified BIN1 as a homeostatic microglial regulator with a non-redundant role in activating proinflammatory response upstream of Apoe, Trem2, and Tyrobp, and upstream of PU.1 and IRF1. BIN1 was predicted to regulate type 1 and 2 interferon responses in microglia in vitro and in vivo. Collectively, these findings offer important insights into microglial BIN1 function, demonstrating its significance in brain inflammatory response. The overall objective of this proposal is to explore BIN1’s role in microglia further, especially in the context of AD pathogenesis, and gain molecular insights. The goal of Aim 1 is to generate 5XFAD:Bin1 cKO mice to elucidate microglial BIN1 function in the modulation of cerebral amyloid burden and amyloid-associated pathophysiology. We will conduct detailed biochemical, molecular, and neuropathological characterization and perform transcriptomics profiling of neuroinflammation and DAM transition to understand BIN1’s role in microglial response to amyloid pathology. Aim 2 studies seek to generate PS19:Bin1 cKO mice to elucidate the involvement of microglial BIN1 function in tau pathophysiology and pathology propagation using detailed neuropathology and comprehensive biochemical, proteomics, and molecular analyses. Aim 3 studies will investigate the mechanistic role of BIN1 as a crucial regulator of early inflammatory signaling events in microglia. We will use unbiased and hypothesis-driven approaches to define the microglial BIN1 interactome and elucidate how BIN1 and its binding partners are reorganized in a context-dependent manner to facilitate immune signaling via key microglial receptors. This timely and unique proposal is highly innovative. Our strategy to use microglia-specific inducible Bin1 cKO mice represents the most direct in vivo approach to rigorously investigate how microglial BIN1 regulates AD pathophysiology and gain insights using comprehensive transcriptomics, proteomics, and interactome characterization. We believe that the successful completion of the proposed research will fill significant gaps in our understanding of BIN1 as a risk factor for LOAD and guide future functional characterizations of molecular pathways and pathogenic mechanisms regulated by this major LOAD risk gene.