Extracellular vesicle transport of brain-derived proteins to the blood in Alzheimer disease

摘要 越来越多的证据表明，细胞外小泡(EVS)，即可以 由大多数类型的细胞分泌，介导细胞间的通讯，在 阿尔茨海默病(AD)的发病和/或进展。具体地说，已经证明 淀粉样β蛋白(A-β)、tau和其他与AD密切相关的蛋白质的细胞间转移 阿尔茨海默病的发病机制以及在中枢神经系统内的病毒样传播 中枢神经系统(CNS)至少部分通过EVS进行调节。此外，电动汽车携带独特的，疾病- 体内血液、脑脊液(CSF)中可检测到特定的、具有重要功能的货物 和其他体液。最近，我们和其他人不仅证明了电动汽车可能 通过血脑屏障(BBB)，虽然转运机制尚不清楚，但 此外，以血液为基础但具有中枢神经系统特异性的EV分子可能是生物标志物的宝贵来源 神经退行性疾病，包括阿尔茨海默病。在这项研究中，我们将首先使用我们先进的蛋白质组学 筛选AD相关神经元亚群或脑的EV表面标志物的技术 区域以识别更多CNS和AD特异性EV标记，并同时适应我们的纳米颗粒 分选和单分子定量技术使CNS来源的高纯度分离成为可能 血浆中EVS和高精度定量这类EVS中的蛋白质以解决几个主要问题 当前领域的挑战。使用当前已知的(例如，L1CAM)和更多的CNS-和AD- 来自中枢神经系统的特定EV表面标记，以及现有和进一步发展的EV分离 和量化技术，然后我们将比较包含L1CAM的AD相关生物标记物 EVS或来自人类患者血浆中AD相关神经元亚群的EVS， 重点关注经典AD蛋白和已知EV候选蛋白的性能，特别是Aβ，tau， α-突触核蛋白及其各种异构体；必要时可研究其他新的靶点。为 已证实的AD相关EV蛋白，我们将进一步检测其在动物体内的纵向变化 建立模型并探索它们从大脑传输到血液的机制(例如， 细胞和动物模型中的交叉BBB)以及改变它们成为未来新型AD的可能方法 治疗目标。拟议的实验可能会奠定基础，导致 廉价和广泛可用的测试，以帮助AD诊断和/或疾病跟踪。此外， 拟议的一系列研究是阐明新的潜在清除的重要的第一步 潜在毒性CNS蛋白物种的途径，最终可能提供关键机会 从治疗上解决与阿尔茨海默病神经变性相关的病理问题。

Summary Growing evidence suggests that extracellular vesicles (EVs), membrane vesicles that can be secreted by most cell types to mediate intercellular communication, play important roles in the initiation and or progression of Alzheimer disease (AD). Specifically, it has been demonstrated that cell-to-cell transfer of amyloid beta (Aβ), tau, and other proteins critically involved in AD pathogenesis, as well as the prion-like propagation of AD pathology within the central nervous system (CNS) is mediated at least in part via EVs. Additionally, EVs carrying unique, disease- specific, and functionally important cargo are detectable in vivo in blood, cerebrospinal fluid (CSF) and other body fluids. More recently, we and others have demonstrated not only that EVs may cross the blood-brain barrier (BBB), though the transportation mechanism remains unclear, but also that blood-based but CNS-specific EV molecules can be a valuable source of biomarkers for neurodegenerative diseases, including AD. In this study, we will first use our advanced proteomics techniques to screen for EV surface markers specific to AD-related neuronal subpopulations or brain regions to identify more CNS- and AD- specific EV markers, and in parallel adapt our nanoparticle sorting and single-molecule quantification technologies to enable high-purity isolation of CNS-derived EVs in plasma and high-precision quantification of proteins in such EVs to address several major challenges in the current field. Using the currently known (e.g., L1CAM) and more CNS- and AD- specific, CNS-derived EV surface markers, as well as the existing and further developed EV isolation and quantification technologies, we will then compare AD-related biomarkers in L1CAM-containing EVs or those from AD-related neuronal subpopulations in blood plasma from human patients, focusing on the performance of classic AD proteins and known EV candidates, specifically, Aβ, tau, α-synuclein, and their various isoforms; additional novel targets may be studied when necessary. For the verified AD-related EV proteins, we will further examine their longitudinal changes in animal models and explore the mechanisms by which they are transported from the brain to blood (e.g., crossing BBB) in cellular and animal models and potential ways to alter them as novel future AD treatment targets. The proposed experiments will likely establish the foundation leading to an inexpensive and widely available test to aid in AD diagnosis and/or disease tracking. Additionally, the proposed set of studies is an important initial step toward elucidating a novel potential clearance pathway for potential toxic CNS protein species and ultimately it may provide critical opportunities for therapeutically addressing the pathology associated with neurodegeneration in AD.