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

项目摘要/摘要：痴呆症困扰着全球4700万人，其经济影响 超过8000亿美元；没有疾病修饰疗法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 纤维形成特征性包涵体，与疾病进展有关。通过哪些机制 最初的αS纤维形态尚不清楚，但阻止它们的出现是预防疾病的关键。羧基末端 αS的截断(C-截断)在疾病发病机制中可能是至关重要的，因为它在- 在体外，C-截短型αS比全长αS.蛋白水解物更容易自发组装成纤维 这些截短物种的形成，可能是由衰老相关的溶酶体损伤促进的，可能是 疾病中最初病理形成的关键。此外，C-截短αS在疾病中的增加表明 病理作用，包裹体中15-20%的αS被截断。因此，这个项目的目标是 表征自然形成的C-截短种αS的聚集成病理性纤维和 在体内刺激α、S和tau病理协同形成。 具体目的一：调查生理性C端截短αS的病理倾向 共核病和直肠病的体外和细胞模型的聚合。在这里，我将描述 自然形成的C-截短型αS在体内外的聚集倾向 模特们。我的工作假设是截短形式的αS会很容易聚集并协同诱导 全长αS和陶原纤层。这些结果将阐明聚集的分子机制和 为进一步的体内工作做好准备。 具体目标二：测定生理性C末端截短αS在脑缺血再灌注损伤中的启动病理能力 应用脑纤维注射和重组技术建立小鼠突触核病和结缔组织病模型 腺相关病毒(RAAV)。家族聚集型αS突变体在小鼠体内的病毒过表达结果 用来模拟疾病的神经退行性特征。此外，注射预制的αS纤维已被 在转基因动物中被发现会加速疾病的发展。我的工作假设是注射 截短的αS纤维和反之，截短的αS在小鼠体内过表达重组腺病毒将引发αS和tau 病理学。这些实验将揭示αS截断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.