Autophagy-dependent exosome loading and biogenesis in AD and FTD

AD 和 FTD 中自噬依赖性外泌体负载和生物发生

基本信息

批准号：
10176326
负责人：
Jayanta Debnath
金额：
$ 65.02万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-15 至 2022-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10176326
关键词：
Address Affect Alzheimer&apos s Disease Amyloid Amyloid beta-Protein Precursor Astrocytes Autophagocytosis Autophagosome Binding Proteins Biochemical Biogenesis Bioinformatics Biotinylation Cell Death Cell Survival Cells Cellular biology Cleaved cell Cytoplasm Defect Disease Equilibrium Frontotemporal Dementia Functional disorder Goals Lead Lipids Lysosomes Mediating Membrane Microglia Microtubules Modeling Molecular Multivesicular Body Mus N-terminal Nerve Degeneration Neurodegenerative Disorders Neurofibrillary Tangles Neuroglia Neurons Oligodendroglia PGRN gene Pathogenesis Pathologic Pathway interactions Peptide Signal Sequences Peptides Population Process Protein Isoforms Protein Secretion Proteins Proteomics RNA RNA-Binding Proteins Role Senile Plaques Specific qualifier value Sphingomyelinase Stress Synapses Tauopathies Testing To specify Vesicle amyloid peptide base exosome glial activation hyperphosphorylated tau misfolded protein novel protein TDP-43 protein aggregation protein degradation protein misfolding proteostasis recruit stress granule tau Proteins trafficking

项目摘要

PROJECT SUMMARY Alzheimer's Disease (AD) is characterized by the progressive accumulation of abnormally cleaved A amyloid peptides and hyperphosphorylated tau proteins, which lead to amyloid plaques and neurofibrillary tangles, respectively. While it remains unclear what triggers these proteinopathies, several lines of evidence indicate that defects in intracellular trafficking may regulate AD pathogenesis. Importantly, emerging evidence suggests that AD-related proteins, including tau, amyloid precursor protein (APP) and A amyloid peptides are secreted via exosomes. Despite these findings, it remains unclear what regulates the formation and packaging of exosomes, whether exosome biogenesis is functionally connected to intracellular trafficking of disease-related proteins, whether neurons and glia develop different mechanism to process these proteins, and if so, how abnormal proteostasis in neurons and glia cooperatively promotes neurodegeneration. We have discovered a new pathway in which the autophagy machinery specifies packaging and secretion of proteins within exosomes. Traditionally studied as an autodigestive pathway that promotes cell survival during stress, autophagy also promotes the unconventional secretion of proteins lacking N-terminal signal sequences. Using a proximity-based biotinylation (BioID) proteomics strategy, we have uncovered ~90 novel putative targets of autophagy-dependent secretion, including numerous proteins released within exosomes. These proteins biochemically interact with MAP1LC3B, a mammalian ATG8 isoform and autophagy regulator crucial for cargo sequestration. Based on these results, we hypothesize that the autophagy machinery mediates the LC3-dependent recruitment and packaging of specific intracellular cargo for their secretion via exosomes. Furthermore, we hypothesize that autophagy controls a delicate balance of secretion and intracellular trafficking of disease-relevant proteins in neurons and glia to promote neurodegeneration in AD and FTD. To test these predictions, we will: 1) Dissect whether and how autophagy specifies exosome packaging and secretion in normal and Alzheimer neural cell populations; and 2) Delineate how lysosomal dysfunction in AD and FTD impacts LC3-dependent exosome packaging and proteostasis. These studies are uniquely poised to define new functions for the autophagy machinery in the biogenesis and secretion of exosomes and to delineate its contributions to AD pathogenesis. This multi-PI R01 application synergistically merges the unique expertise of Dr. Jayanta Debnath in the cell biology of autophagy and Dr. Eric Huang in the molecular mechanisms of neurodegenerative diseases to address the goals of RFA-AG-17-051 by uncovering new machineries directing exosome biogenesis and the secretion of exosomal cargo molecules in AD.

项目摘要阿尔茨海默氏病（AD）的特征是绝对裂解的淀粉样蛋白的进行性积累肽和高磷酸化的tau蛋白，导致淀粉样蛋白斑块和神经原纤维缠结，尽管尚不清楚什么触发了这些蛋白质病，但几条证据表明细胞内运输的缺陷可能调节AD发病机理。重要的是，新兴的证据表明该广告相关的蛋白质，包括tau，淀粉样蛋白前体蛋白（APP）和A淀粉样蛋白酶是分泌的通过外泌体。尽管有这些发现，但仍不清楚是什么调节外泌体，外泌体生物发生在功能上是否与疾病相关的细胞内运输有关蛋白质，神经元和神经胶质是否发展出不同的处理这些蛋白质的机制，如果是，则如何神经元和神经胶质的异常蛋白抑制作用可促进神经退行性。我们发现了一种新途径，其中自噬机械指定了包装和分泌外泌体内的蛋白质。传统上研究了一种自动化途径，可在压力，自噬还促进了缺乏N末端信号序列的蛋白质的非常规分泌。使用基于接近性的生物素化（生物学）蛋白质组学策略，我们发现了〜90个新型假定自噬依赖性分泌的靶标，包括在外泌体内释放的许多蛋白质。这些蛋白质与MAP1LC3B，哺乳动物ATG8同工型和自噬调节剂的生物化学相互作用至关重要用于货物隔离。基于这些结果，我们假设自噬机械介导 LC3依赖性募集和特定细胞内货物的包装，以通过外泌体分泌。此外，我们假设自噬控制了分泌和细胞内的微妙平衡在神经元和神经胶质中，与疾病相关蛋白的运输以促进AD和FTD中的神经退行性。到测试这些预测，我们将：1）剖析自噬是否以及如何指定外泌体包装和正常和阿尔茨海默神经细胞群体的分泌； 2）描述AD中的溶酶体功能障碍如何 FTD影响LC3依赖性外泌体包装和蛋白质抗体。这些研究被中毒了在外泌体的生物发生和分泌中定义自噬机械的新功能描述其对AD发病机理的贡献。该多PI R01应用程序协同合并了唯一 Jayanta Debnath博士在自噬细胞生物学和Eric Huang博士的细胞生物学中的专业知识神经退行性疾病的机制通过发现新的新的RFA-AG-17-051的目标指导外泌体生物发生和AD中外泌体货物分子的分泌的机器。