A Drosophila model to investigate prion-like transmission of Huntington's disease

研究亨廷顿病的朊病毒样传播的果蝇模型

• 批准号: 8305582
• 负责人: Margaret Panning Pearce
• 金额: $ 5.39万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-06 至 2013-07-26
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8305582
• 关键词: Adopted; Alzheimer' s Disease; Amyloid; Basal Ganglia; Behavior; Biochemistry; Biophysics; Brain; Brain region; Cell Surface Proteins; Cell surface; Cells; Cellular biology; Cherry - dietary; Coculture Techniques; Complex; Corpus striatum structure; Cultured Cells; Cytoplasm; Data; Deposition; Deterioration; Disease; Disease Progression; Drosophila genus; Extracellular Space; Genes; Genetic; Glutamine; Green Fluorescent Proteins; Hippocampus (Brain); Huntington Disease; Individual; Inherited; Investigation; Knowledge; Lateral; Life; Measures; Mediating; Mentors; Mitotic; Modeling; Motor; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Neurologic; Neurons; Parkinson Disease; Pathology; Peptide Hydrolases; Phenotype; Process; Property; Proteins; RNA Interference; Reporting; Role; Staging; Symptoms; Synapses; Testing; Tissues; Transgenic Organisms; Trypsin; brain tissue; cell type; cognitive function; cytotoxic; cytotoxicity; extracellular; fly; gain of function; human Huntingtin protein; in vivo; insight; loss of function; monomer; motor impairment; mutant; neuron loss; neuronal cell body; neuronal circuitry; polyglutamine; prion-like; protein aggregation; tool; transmission process; uptake

Huntington's disease (HD) is an inherited neurodegenerative disorder characterized by a progressive deterioration in motor and cognitive function, and its primary genetic cause is the expansion of a polyglutamine (polyQ) tract near the N-terminus of the ubiquitously-expressed, cytosolic protein huntingtin (Htt). Mutant Htt adopts a cytotoxic gain-of-function that causes it to polymerize into insoluble, amyloid-like fibrillar aggregates that are initially deposited in medium spiny neurons in the striatum of the basal ganglia but in later stages of disease, spread to neurons in neighboring brain regions (e.g. the hippocampus and cortex). While it is clear that deposition of Htt aggregates correlates with neuronal cell death, the exact mechanism by which they contribute to cytotoxicity or spread through brain tissue is currently unknown. Recent studies suggest that extracellular Htt aggregates have prion-like properties; i.e. they can trigger the templated conformational change of soluble monomers and transmit the misfolded state to naove cells. Further, emerging evidence suggests that aggregates formed by proteins associated with other neurodegenerative disorders (e.g. Alzheimer's and Parkinson's diseases) also adopt prion-like behavior, suggesting that progression of these diseases may occur by a common mechanism. The overall aim of this proposal is to establish a Drosophila model to demonstrate whether prion-like transmission of HD pathology can be recapitulated in vivo and to explore the mechanism(s) involved in this process. Specific Aim 1 investigates whether the aggregation phenotype can be transmitted from neurons expressing aggregation-prone Htt containing a pathogenic polyQ tract to synaptically-connected neurons expressing soluble Htt with a non-pathogenic polyQ tract. Specific Aim 2 explores an alternative but not necessarily mutually exclusive possibility, that Htt-induced aggregation is transmitted between adjacent, non-synaptically-connected cells. These studies will exploit detailed knowledge of Drosophila olfactory neuronal circuitry and various genetic tools to express pathogenic and non-pathogenic Htt proteins in distinct cell types within an individual fly. The focus of Specific Aim 3 is to identify determinants for the lateral transmission of Htt-induced aggregation in a Drosophila model to gain insight into the mechanism(s) involved in this process. These studies will employ a loss-of-function screen in which genes encoding cell surface and secreted proteins are depleted by RNA interference, and effects will be measured by examining how the spread of Htt-induced aggregation to synaptically-connected and/or neighboring cells is altered. Together, these approaches will expand our current understanding of how Htt aggregates propagate between cells with prion-like properties in an in vivo setting, and will lend insight into the mechanism by which the pathology of HD and other neurodegenerative disorders progress along stereotypical paths through the brains of afflicted individuals.

亨廷顿病 (HD) 是一种遗传性神经退行性疾病，其特征是运动和认知功能进行性恶化，其主要遗传原因是普遍表达的胞质蛋白亨廷顿蛋白 (Htt) N 末端附近的聚谷氨酰胺 (polyQ) 束扩张。突变体 Htt 采用细胞毒性功能获得性，使其聚合成不溶性淀粉样蛋白样原纤维聚集体，这些聚集体最初沉积在基底神经节纹状体的中等多棘神经元中，但在疾病后期，扩散到邻近大脑区域（例如海马和皮质）的神经元。虽然很明显 Htt 聚集体的沉积与神经元细胞死亡相关，但它们导致细胞毒性或通过脑组织扩散的确切机制目前尚不清楚。最近的研究表明，细胞外 Htt 聚集体具有类似朊病毒的特性；即它们可以触发可溶性单体的模板化构象变化并将错误折叠状态传递给幼稚细胞。此外，新出现的证据表明，与其他神经退行性疾病（例如阿尔茨海默病和帕金森病）相关的蛋白质形成的聚集体也采取类似朊病毒的行为，这表明这些疾病的进展可能通过共同机制发生。本提案的总体目标是建立果蝇模型，以证明 HD 病理学的朊病毒样传播是否可以在体内重现，并探索该过程中涉及的机制。具体目标 1 研究聚集表型是否可以从表达含有致病性 PolyQ 束的易聚集 Htt 的神经元传递到表达具有非致病性 PolyQ 束的可溶性 Htt 的突触连接神经元。具体目标 2 探索了另一种但不一定相互排斥的可能性，即 Htt 诱导的聚集在相邻的、非突触连接的细胞之间传递。这些研究将利用果蝇嗅觉神经元回路的详细知识和各种遗传工具，在果蝇个体的不同细胞类型中表达致病性和非致病性 Htt 蛋白。具体目标 3 的重点是确定果蝇模型中 Htt 诱导聚集横向传播的决定因素，以深入了解该过程中涉及的机制。这些研究将采用功能丧失筛选，其中编码细胞表面和分泌蛋白的基因被 RNA 干扰耗尽，并且通过检查 Htt 诱导的聚集向突触连接和/或邻近细胞的扩散如何改变来测量效果。总之，这些方法将扩展我们目前对 Htt 聚集体如何在体内环境中具有朊病毒样特性的细胞之间传播的理解，并将有助于深入了解 HD 和其他神经退行性疾病的病理学沿着受苦个体大脑的刻板路径发展的机制。