Rab proteins and alpha-Synuclein toxicity in Neurodegenerative Disease

描述(由申请人提供)：拟议研究的目的是阐明RAB蛋白在1-突触核蛋白毒性中的作用。α-突触核蛋白(1Syn)是路易体的主要成分，在帕金森病(PD)和相关疾病(如路易体痴呆(DLB)和多系统萎缩(MSA))中病理发现。1Syn的异常折叠、聚集和沉积被认为是神经元功能障碍和变性发展的中心。最近在酵母中的数据表明，1SY的过表达干扰了细胞内的转运，导致异常的囊泡聚集、聚集和毒性。RAB蛋白是RAS超家族小分子GTP结合蛋白的成员，在细胞内转运、膜转运甚至神经递质释放中起重要作用。Rab蛋白在几种PD模型中的过度表达，包括酵母、蠕虫和苍蝇，以及啮齿动物的初级神经元，挽救了1Syn的毒性。此外，在几种神经退行性疾病中，Rab蛋白与1Syn的结合增加，包括DLB，MSA，可能还有PD。低聚形式的突变体1Syn似乎同样增加了Rab的结合。我们自己的初步数据证实了Rab蛋白的保护作用，并表明它们也减少了1Syn毒性细胞模型中存在的1Syn寡聚体的数量。综上所述，这些发现支持这样的假设，即1Syn的积累干扰了正常的Rab功能，通过破坏细胞内转运而导致毒性。或者，特定的Rab蛋白通常可以防止有毒的1Syn物种的形成和积累，但在模型系统和病理条件下(如PD)的过度表达会使其不堪重负。因此，增强RAB功能可能为帕金森病和相关的神经退行性疾病提供新的治疗机会。因此，拟议的实验将弄清RAB过度表达对1Syn具有保护作用的机制。我的长期目标是发展一项职业，旨在通过基础研究和翻译研究，了解并最终找到治疗帕金森病和相关神经退行性疾病的新疗法。在布拉德利·海曼博士的指导下，拟议的研究和职业发展计划将帮助我实现眼前的目标，获得最新的分子和遗传技能，并学习最先进的成像技术，以补充我强大的神经解剖学背景。Xandra Breakefield博士和Miguel Esteves博士在病毒操纵和CNS基因传递方法方面的其他专业知识也将推动我最终成为基因治疗专家的目标，并将我的工作转化为潜在的患者治疗方法。发展这些研究技能，加上我持续的临床培训和经验，对于成为一名致力于翻译神经科学的成功、独立的临床医生和科学家至关重要。 公共卫生相关性：拟议的研究结果对于理解1-突触核蛋白在帕金森病和相关神经退行性疾病中的作用尤其相关和关键。拟议的研究将检验1-突触核蛋白干扰Rab蛋白功能和细胞内转运，导致神经元功能障碍和毒性的假设。此外，RABS的过表达可能会减轻这种毒性。

DESCRIPTION (provided by applicant): The objective of the proposed research is to elucidate the role of Rab proteins in 1-synuclein toxicity. Alpha-synuclein (1Syn) is a principal component of Lewy bodies found pathologically in Parkinson disease (PD) and related disorders, such as dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Abnormal folding, aggregation, and deposition of 1Syn are believed to be central to development of neuronal dysfunction and degeneration. Recent data in yeast indicate that over-expression of 1Sy interferes with intracellular trafficking and results in abnormal vesicle accumulation, clustering, and toxicity. Rab proteins are members of the Ras super-family of small GTP-binding proteins and have critical functions in intracellular trafficking, membrane transport, and even neurotransmitter release. Over-expression of Rab proteins in several PD models, including yeast, worms, and flies, as well as rodent primary neurons, rescues 1Syn toxicity. Moreover, Rab proteins show increased binding to 1Syn in several neurodegenerative disorders, including DLB, MSA, and possibly also PD. Oligomeric forms of mutant 1Syn likewise appear to have increased Rab binding. Our own preliminary data confirm Rab proteins' protective role, and show that they also reduce the amount of oligomeric forms of 1Syn present in cell models of 1Syn toxicity. Together, these findings support the hypothesis that accumulation of 1Syn interferes with normal Rab function, leading to toxicity via disruption of intracellular trafficking. Alternatively, specific Rab proteins may normally protect against formation and accumulation of toxic 1Syn species, but are overwhelmed by overexpression in model systems and pathological conditions, such as PD. Enhancing Rab function may thus provide a new therapeutic opportunity for PD and related neurodegenerative disorders. The proposed experiments will therefore discern the mechanisms whereby Rab overexpression confers protection against 1Syn. My long-term goal is to develop a career aimed at understanding and ultimately finding novel therapies for PD and related neurodegenerative disorders through basic and translational research. The proposed research and career development plan, under the supervision of Dr. Bradley Hyman, will help achieve my immediate goals to obtain up-to-date molecular and genetic skills and to learn state-of-the-art imaging techniques to complement my strong neuroanatomical background. Additional expertise in viral manipulation and CNS gene delivery methods from Drs. Xandra Breakefield and Miguel Esteves will also forward my goal of eventually becoming a gene therapy expert and translating my work into potential patient therapies. Developing these research skills, along with my continued clinical training and experience are critical to becoming a successful, independent clinician-scientist committed to translational neuroscience. PUBLIC HEALTH RELEVANCE: The results of the proposed research are particularly relevant and critical to understanding the role of 1- synuclein in Parkinson disease and related neurodegenerative disorders. The proposed studies will test the hypothesis that 1-synuclein interferes with Rab protein function and intracellular trafficking, leading to neuronal dysfunction and toxicity. Furthermore, over-expression of Rabs may ameliorate this toxicity.