Molecular impact of endolysosomal dysfunction on neuron-glia communication pathways

项目摘要 阿尔茨海默病是一种神经退行性疾病，也是世界范围内最常见的痴呆症。 尽管有几十年的研究，但很少有治疗方法可以延缓或防止AD的进展。逆行 通过依赖追溯分子的货物识别进行贩运已经成为一种关键的细胞过程，即 阿尔茨海默病和其他形式的痴呆症患者的基因突变或中断。逆转录基因的条件性敲除 在神经元中导致牛磺酸和淀粉样蛋白β(Aβ)分泌增加，这是与AD有关的标志性蛋白质病理。 这种神经分泌因子的环境导致小胶质细胞和星形胶质细胞这两种胶质细胞的炎症。 被认为影响神经退行性变的进程。在这项提议中，我的目标是研究一系列事件 将神经元逆转录酶破坏与神经胶质炎症联系起来，表征涉及的特定细胞状态变化， 并找出影响这一效应的关键因素。我将使用基因工程干细胞来解决这个问题- 人类神经元、小胶质细胞和星形胶质细胞的衍生模型。小胶质细胞也表达逆转录病毒组分和 在阿尔茨海默病中上调这些因子，但很少有关于逆转聚体功能的研究，特别是在小胶质细胞。在AIM 2中I 因此，我将探索逆转录相关突变在早期对小胶质细胞的影响 在小鼠中的老化，一个与带有这些突变的患者出现痴呆症的时间点相当的时间点。这就做 此外，利用干细胞模型剖析小胶质细胞中诱导的功能和信号变化 逆转录病毒的破坏。最后，尽管已经有几项研究关注逆转录病毒对 特定的受体，鲜为人知的逆转录突变对蛋白质转运的系统水平的影响。 内小体。为了确定可能致病的逆转录依赖信号通路，我开发了 新的蛋白质组学工具来量化内体蛋白质组的变化，并将使用这些工具来比较它们的影响 神经细胞和小胶质细胞内小体上不同的逆转录突变。最终目标是了解如何 逆转录病毒干扰会影响脑细胞状态，并导致致病信号改变。

Project Abstract Alzheimer’s disease (AD) is a neurodegenerative disease and the most common form of dementia worldwide. Despite decades of research, there are few therapies that can delay or prevent AD progression. Retrograde trafficking through retromer-dependent cargo recognition has emerged as a critical cellular process that is mutated or disrupted in patients with AD and other forms of dementia. Conditional knockout of retromer genes in neurons leads to increased secretion of Tau and Amyloid β (Aβ), hallmark protein pathologies linked to AD. This milieu of neuronal-secreted factors leads to inflammation in microglia and astrocytes, two glial cell types thought to influence the progression of neurodegeneration. In this proposal, I aim to study the cascade of events linking neuronal retromer disruption to glial inflammation, characterizing the specific cell state changes involved, and identify the key factors that mediate this effect. I will address this aim using genetically engineered stem cell- derived models of human neurons, microglia, and astrocytes. Microglia also express retromer components and upregulate these factors in AD, yet there are few studies of retromer function specifically in microglia. In Aim 2 I will therefore explore the effects of retromer-related mutations specifically on microglia in the context of early aging in mice, a comparable time point to when dementia manifests in patients with these mutations. I will additionally utilize stem cell models to dissect the functional and signaling changes that are induced in microglia with retromer disruption. Finally, although there have been several studies looking at the effects of retromer on specific receptors, little is known about the systems-level effects of retromer mutations on protein trafficking to the endosomes. To identify retromer-dependent signaling pathways that may be pathogenic, I have developed novel proteomics tools to quantify endosomal proteome changes and will use these tools to compare the effects of different retromer mutations on neuronal and microglial endosomes. The ultimate goal is to understand how retromer disruption affects brain cell states and leads to pathogenic signaling changes.