Mechanisms of mutanthuntingtin aggregate engulfment and spreading by phagocytic glia

吞噬细胞胶质细胞吞噬和扩散突变亨廷顿蛋白聚集体的机制

• 批准号: 10514794
• 负责人: Margaret Panning Pearce
• 金额: $ 9.3万
• 依托单位: UNIVERSITY OF THE SCIENCES PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-19 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10514794
• 关键词: Address; Adult; Age; Alzheimer' s Disease; Anatomy; Appearance; Astrocytes; Axon; Biological; Biology; Brain; Brain region; Cell Culture Techniques; Cells; Cessation of life; Complex; Cultured Cells; Cytoplasm; Data; Defect; Disease; Drosophila genus; Environment; Equilibrium; Functional disorder; Generations; Genes; Genetic Screening; Goals; Growth; Homologous Gene; Huntington Disease; Huntington gene; Huntington protein; In Vitro; Incidence; Interneurons; Lesion; Mammalian Cell; Measures; Mediating; Membrane; Modeling; Molecular; Mus; Nerve Degeneration; Neuraxis; Neurodegenerative Disorders; Neuroglia; Neurons; Neuropathogenesis; Olfactory Pathways; Orthologous Gene; Outcomes Research; Parkinson Disease; Pathogenesis; Pathogenicity; Pathologic; Pathway interactions; Patients; Pattern; Phagocytes; Phagocytosis; Phagosomes; Prions; Property; Proteins; Public Health; Publishing; RNA Interference; Reporting; Research; Research Support; Role; SNAP receptor; Supervision; Synapses; System; Testing; Time; Toxic effect; Work; age related neurodegeneration; alpha synuclein; base; cell type; defined contribution; fly; frontotemporal lobar dementia-amyotrophic lateral sclerosis; graduate student; in vivo; insight; misfolded protein; monolayer; mutant; nerve injury; nervous system disorder; neuron loss; neuropathology; neuroprotection; neurotoxic; new therapeutic target; novel; postsynaptic neurons; presynaptic; prion-like; protein aggregation; protein misfolding; response; response to injury; scavenger receptor; spatiotemporal; tau Proteins; therapeutic target; therapeutically effective; transmission process; undergraduate student

PROJECT SUMMARY Neurodegenerative diseases are characterized by the progressive appearance of insoluble inclusions that arise due to protein misfolding in the brain. Much research has focused on determining mechanisms by which these protein lesions cause dysfunction and loss of neurons and glia. Accumulating evidence supports the hypothesis that protein assemblies associated with most neurodegenerative diseases propagate in the brain by templating the aggregation of properly-folded versions of the same protein, similarly to infectious prions. However, it is still not well understood how “prion-like” aggregates spread between different cell types in the brain or the relevance of this to neuropathogenesis. The long-term goal of our research is to identify mechanisms underlying protein aggregate-induced toxicity and spreading between neurons and glia in the degenerating brain. The overall objective of this project is to determine normal and pathological functions of phagocytic glia in response to formation of mutant huntingtin (mHTT) aggregates in neurons. Prior research showing that glial responses to neural injury shift from beneficial to harmful over time, and emerging evidence that phagocytic glia participate in aggregate clearance and spreading provide rationale for the current project. The central hypothesis is that incomplete clearance of engulfed neuronal mHTT aggregates by phagocytic glia promotes formation and growth of a reservoir of seeding-competent, prion-like species in the brain. This hypothesis was formulated based on findings that glia mediate prion-like transfer of mHTT, tau, and a-synuclein aggregates, and that phagocytic clearance of engulfed debris becomes less effective with age and in the disease state. Our recent work indicates that prion-like transfer of mHTT aggregates between synaptically-connected neurons requires Draper-dependent phagocytosis, an evolutionarily-conserved glial pathway for clearing debris in the brain. The central hypothesis will be tested in three Specific Aims, carried out in complementary in vivo Drosophila and in vitro mammalian cell culture models. In Aim 1, effects of neuronal mHTT aggregates on glial responses to neural injury will be measured in adult fly brains to gain insight into whether mHTT aggregate engulfment leads to glial dysfunction. In Aim 2, RNAi-based forward genetic screens will identify modifiers of prion-like spreading of engulfed neuronal mHTT aggregates to the glial cytoplasm. In Aim 3, roles of the mammalian Draper homolog MEGF10 in mHTT aggregate transfer between co-cultured neuronal and astrocytic cells will be determined. These studies will identify novel mechanisms about the basic biology underlying phagocytosis, and disease-related mechanisms that drive protein aggregate-induced neurodegeneration in multiple cell types. The proposed research is significant because it addresses critical questions of how phagocytic glia interact with neurons to drive pathogenesis in potentially many neurological disorders. Our findings will reveal new information about aggregate-related pathogenesis underlying neurodegeneration and have great potential to identify targets for novel therapies that treat the underlying cause of these fatal disorders.

项目摘要 神经退行性疾病的特征在于在神经系统中出现的不溶性包涵体的进行性出现， 因为大脑中的蛋白质错误折叠许多研究都集中在确定这些机制， 蛋白质损伤引起神经元和神经胶质的功能障碍和损失。越来越多的证据支持这一假设 与大多数神经退行性疾病相关的蛋白质组装通过模板在大脑中传播， 相同蛋白质的正确折叠版本的聚集，类似于传染性朊病毒。但是依然 还不清楚“朊病毒样”聚集体如何在大脑中不同细胞类型之间传播， 神经发病机制的关系。我们研究的长期目标是确定蛋白质 聚集诱导的毒性以及在退化的大脑中神经元和神经胶质之间的扩散。整体 本项目的目的是确定吞噬胶质细胞的正常和病理功能， 在神经元中形成突变亨廷顿蛋白（mHTT）聚集体。先前的研究表明， 随着时间的推移，神经损伤从有益变为有害，吞噬胶质细胞参与 骨料清除和摊铺为当前项目提供了依据。核心假设是， 吞噬胶质细胞对吞噬的神经元mHTT聚集体的不完全清除促进形成和生长 大脑中有一个能播种的朊病毒样物质的储存库。这一假设是基于 发现胶质细胞介导mHTT、tau和α-突触核蛋白聚集体的朊病毒样转移， 随着年龄的增长和疾病状态，清除吞噬的碎片变得不那么有效。我们最近的研究表明 mHTT聚集体在突触连接的神经元之间的朊病毒样转移需要依赖Draper的 吞噬作用，一种进化上保守的用于清除大脑中碎片的神经胶质途径。核心假设 将在三个特定目标中进行测试，在互补的体内果蝇和体外哺乳动物细胞中进行 文化模式在目的1中，将研究神经元mHTT聚集体对神经损伤的胶质反应的影响。 在成年果蝇脑中测量，以了解mHTT聚集体吞噬是否导致神经胶质功能障碍。 在目标2中，基于RNAi的正向遗传筛选将识别吞噬神经元的朊病毒样扩散的修饰剂， mHTT聚集到神经胶质细胞质。在目标3中，哺乳动物德雷珀同源物MEGF 10在mHTT中的作用 测定共培养的神经元和星形胶质细胞之间的聚集转移。这些研究将 确定吞噬作用的基础生物学新机制和疾病相关机制 在多种细胞类型中驱动蛋白质聚集体诱导的神经变性。拟议的研究是 重要的是，它解决了吞噬胶质细胞如何与神经元相互作用的关键问题， 潜在的许多神经系统疾病的发病机制。我们的发现将揭示关于 聚集相关的发病机制的神经变性，并有很大的潜力，以确定目标， 治疗这些致命疾病的根本原因的新疗法。