Towards Understanding the Initiating Role of Truncated Alpha-Synuclein in Neurodegeneration

项目摘要/摘要：痴呆症在全球范围内困扰着4700万人， 超过8000亿美元;没有疾病修饰疗法存在的神经退行性疾病是 最常见的病因。α-突触核蛋白（αS）在多种神经退行性疾病中聚集成毒性纤维 其中原纤维形成与疾病进展有关的特征性内含物。的机制 最初αS纤维形成尚不清楚，但阻止它们的出现是预防疾病的关键。羧基末端 αS的截短（C-截短）可能在疾病发病机制中至关重要，因为它已在- 在体外，C截短的αS比全长αS更容易自发地组装成原纤维。蛋白水解 这些截短的种类的形成，可能是由衰老相关的溶酶体损伤促进的， 疾病中初始病理形成的关键。此外，C-截短的αS在疾病中增加，表明 病理作用，其中包涵体中15-20%的αS被截短。因此，本项目的目的是 表征天然形成的C截短αS种类聚集成病理性原纤维的能力， 刺激体内αS和tau病理协同形成。 具体目的1：研究生理性C-末端截短αS在病理学上 在体外和突触核蛋白病和tau蛋白病的细胞模型中聚集。在此，我将描述 使用充分表征的方法，在体外和体内天然形成的C-截短αS的聚集倾向 模型我的工作假设是截短形式的αS将容易聚集并协同诱导 全长αS和tau纤维形成。这些结果将阐明聚集的分子机制， 为进一步的体内研究奠定了基础。 具体目标二：确定生理性C-末端截短的αS在细胞中引发病理学的能力。 使用脑原纤维注射和重组的突触核蛋白病和tau蛋白病的小鼠模型 腺相关病毒（rAAV）。小鼠中家族性聚集倾向αS突变体的病毒过表达结果 用于疾病模型的神经退行性特征。此外，注射预先形成的αS原纤维已被证明是有效的。 在转基因动物中发现加速疾病的进展。我的工作假设是， 截短的αS原纤维，相反，小鼠中截短的αS的rAAV过表达将启动αS和tau蛋白的表达。 病理这些实验将揭示αS截短在神经退行性疾病中的致病作用。

Project Summary/Abstract: Dementia afflicts 47 million individuals worldwide and has an economic impact of more than $800 billion; neurodegenerative diseases for which no disease modifying therapies exist are the most common etiology. α-synuclein (αS) aggregates into toxic fibrils in multiple neurodegenerative diseases where the fibrils form characteristic inclusions implicated in disease progression. Mechanisms through which initial αS fibrils form is unclear, and yet halting their appearance is key to preventing disease. Carboxy-terminal truncation (C-truncation) of αS may be crucial in disease pathogenesis, as it has been repeatedly shown in- vitro that C-truncated αS spontaneously assembles into fibrils more readily than full-length αS. Proteolytic formation of these truncated species, possibly promoted by aging associated lysosomal impairment, may be key to initial pathology formation in disease. Additionally, C-truncated αS is increased in disease suggesting a pathologic role, where 15-20% of αS in inclusions is truncated. Therefore, The Aims of this project are to characterize naturally formed C-truncated species of αS for their ability to aggregate into pathologic fibrils and stimulate synergistic formation of αS and tau pathology in-vivo. Specific Aim one: Investigate the propensity of physiologic C-terminally truncated αS to pathologically aggregate in-vitro and in cellular models of synucleinopathy and tauopathy. Herein, I will characterize the aggregation propensity of naturally formed C-truncated αS both in-vitro and in-vivo using well characterized models. My working hypothesis is that truncated forms of αS will aggregate readily and synergistically induce full-length αS and tau fibril formation. These results will elucidate molecular mechanisms of aggregation and set the stage for further in-vivo work. Specific Aim two: Determine the ability of physiologic C-terminally truncated αS to initiate pathology in mouse models of synucleinopathy and tauopathy utilizing cerebral fibril injection and recombinant adeno associated virus (rAAV). Viral overexpression of familial aggregation prone αS mutants in mice results in neurodegenerative features used to model disease. Additionally, injection of preformed αS fibrils has been found to hasten progression of the disease in transgenic animals. My working hypothesis is that injection of truncated αS fibrils, and conversely rAAV overexpression of truncated αS in mice will initiate αS and tau pathology. These experiments will uncover pathogenic roles for αS truncation in neurodegenerative diseases.