Role of central and peripheral immune crosstalk in FTD-Grn neurodegeneration

项目摘要 这项提议的目的是了解中枢和外周神经系统改变的机制。 神经免疫信号串扰参与颗粒蛋白前体的额颞叶痴呆的神经退行性变 突变（FTD-GRN），阿尔茨海默病（AD）相关痴呆（ADRD），以及最常见的痴呆 在60岁以下的人群中。GRN突变是显性遗传FTD的主要原因之一。这些 GRN突变通常导致PGRN单倍不足，血浆颗粒蛋白原水平降低>50% 相对于对照。PGRN涉及多种功能，包括炎症和溶酶体功能。 体内平衡目前尚不清楚神经退行性过程是否仅由功能失调的神经元驱动， 脑驻留小胶质细胞或是否过度激活的外周免疫系统有助于 神经炎症和神经变性过程。由于血脑屏障渗漏已在 在AD和FTD患者中，浸润的单核细胞可能在突触修剪中起关键作用， FTD中的神经退行性变迄今为止一直被忽视。因此，我们的研究将集中在调查 外周免疫细胞和小胶质细胞之间的功能障碍性串扰程度及其对神经元的影响 在FTD-GRN的各种小鼠和人iPSC衍生模型中的完整性和功能。在目标1中，我们建议 使用基于iPSC衍生神经元（i-N）、小胶质细胞（i-MG）和单核细胞/巨噬细胞的FTD人体模型 (i-MO/i-MAC），结合创新的纵向成像技术， 显微镜（RM），研究人类中央和外周髓系细胞功能障碍的机制及其 在FTD的背景下，与神经退行性变相关。此外，我们将测试几种药物 目前正在临床开发用于增加PGRN表达和逆转PGRN表达的其他医学病症。 小鼠FTD-GRN神经元的神经变性，因为它们能够拯救人I- MG、i-MO/i-MAC和i-N培养物，这将支持其作为FTD患者治疗的潜在开发。 在目标2中，我们将在FTD-GRN小鼠模型中使用GrnR 493 X/+进行补充体内研究。 突变和PGRN单倍不足，我们以前报告的神经变性和溶酶体 体外功能障碍。我们将检验外周免疫细胞浸润溶酶体的假设， 功能障碍在该FTD-GRN动物模型中导致神经炎症和神经变性。在Aim中 3，我们将定义并验证FTD的稳健、保守和功能定义的疾病相关特征- 相关的小胶质细胞/单核细胞用于系统水平的比较分析，生物信息学驱动分析，以及未来 化学基因组学筛选

PROJECT SUMMARY The goal of this proposal is to understand the mechanisms by which alterations in central and peripheral neuroimmune signaling crosstalk contribute to neurodegeneration in frontotemporal dementia with progranulin mutations (FTD-GRN), an Alzheimer’s Disease (AD)-related dementia (ADRD), and the most common dementia in people younger than 60. GRN mutations are among the leading causes of dominantly inherited FTD. These GRN mutations typically cause PGRN haploinsufficiency, with plasma progranulin levels reduced by >50% relative to controls. PGRN has been implicated in a variety of functions, including inflammation and lysosomal homeostasis. It is unclear whether neurodegenerative processes are driven solely by dysfunctional neurons and brain-resident microglia or whether hyperactivation of the peripheral immune system contributes to neuroinflammatory and neurodegenerative processes. As blood-brain barrier leakage has been reported in patients with AD and FTD, it is possible that infiltrating monocytes play a key role in synaptic pruning and neurodegeneration in FTD that has so far been over-looked. Thus, our studies will focus on investigating the extent of dysfunctional crosstalk between peripheral immune cells and microglia and its effects on neuronal integrity and function in various mouse and human iPSC-derived models of FTD-GRN. In Aim 1, we propose to use human models of FTD based on iPSC-derived neurons (i-N), microglia (i-MG) and monocytes/macrophages (i-MO/i-MAC) in 2D or 3D culture, together with an innovative longitudinal imaging technology, robotic microscopy (RM), to investigate mechanisms of human central and peripheral myeloid cell dysfunction and its associated contribution to neurodegeneration in the context of FTD. In addition, we will test several drugs currently in clinical development for other medical conditions that increase PGRN expression and reverse neurodegeneration of mouse FTD-GRN neurons for their ability to rescue the disease phenotype of human i- MG, i-MO/i-MAC, and i-N cultures, which will support their potential development as treatments for FTD patients. In Aim 2, we will conduct complementary in vivo studies in mouse models of FTD-GRN with the GrnR493X/+ mutation and PGRN haploinsufficiency in which we previously reported neurodegeneration and lysosomal dysfunction in vitro. We will test the hypothesis that infiltration of peripheral immune cells with lysosomal dysfunction contributes to neuroinflammation and neurodegeneration in this animal model of FTD-GRN. In Aim 3, we will define and validate a robust, conserved, and functionally defined disease-associated signature of FTD- associated microglia/monocytes for systems-level comparative analysis, bioinformatic driver analysis, and future chemical genomics screens.