Alpha-synuclein is crucial for neuronal function and survival-Characterization of a novel conditional alpha-synuclein knockout mouse model

联系PD/PI：Manfredsson，Fredric P 项目总结 我们目前对帕金森病(PD)的分子病因学的了解是不完整的， 这很可能是多种相互作用因素的产物。帕金森病分子病理学研究的最佳参与者 是α-突触核蛋白(α-syn)。编码α-SYN的基因的突变和倍增导致遗传性形式 警局的。此外，α-syn在路易小体和轴突中的存在为其与 特发性帕金森病。一种常见的假设是，过多的α-SYN和随之而来的聚集导致 直接毒性功能获得事件中的神经毒性。相反，也有人建议α-SYN 聚集可能通过将蛋白质从其正常的细胞位置移走并减少而危及神经元 它在中毒性功能丧失事件中的作用。这个问题仍然是一个有争议的话题。尽管存在这种模棱两可的情况， 作为一种策略，减少中枢神经系统中α-SYN的方法是一个活跃的研究领域 治疗帕金森病。我们在大鼠和非人灵长类动物上发表的数据，以及在小鼠身上的初步数据，支持 不同的观点，表明从成熟的多巴胺(DA)神经元中消除α-SYN并不是保护作用，而是 相反，它是有毒的。利用我们新开发的条件性α-SYN基因敲除小鼠，我们拟议的研究将 明确黑质纹状体系统中α-SYN表达减弱/减少所导致的后果。 用重组腺相关病毒载体将Cre重组酶(ICre)传递给携带α-Flow的成年小鼠的多巴胺能神经元 α等位基因将使我们能够有效地消除成熟神经元中SYN的表达。这种方法解决了 通过阻止假想的代偿性适应来限制当前生殖系小鼠模型的局限性 当α-SYN表达在发育过程中被取消时发生。以下提案将利用这一新的 小鼠模型：1)表征神经退变效应的模式、时间和α-SYN的剂量依赖关系 关于黑质纹状体系统和由此导致的运动行为障碍。2)定义 其模式的退化及其与先前被认为参与的细胞事件的标志物的关联 帕金森病的退行性变(DA处理不当，氧化/硝化应激，蛋白酶体/溶酶体功能障碍，以及 小胶质细胞激活)在去除α-SYN后变性的早期和晚期。 这一提议将回答一个挥之不去的问题，即α-SYN是否对血管的功能和生存至关重要 成熟的DA神经元，同时也提供了一种新的基于小鼠的工具来研究α-SYN诱导的DA的重要性 神经退行性变用于联核病的研究。这些目标的成功实现将推进 我们开发旨在阻止α-SYN引起的神经退行性变的治疗策略的知识和能力 功能障碍。 项目摘要/摘要第6页

Contact PD/PI: Manfredsson, Fredric P PROJECT SUMMARY Our current understanding of the molecular etiology of Parkinson's disease (PD) is incomplete and likely the product of multiple interacting factors. The best-validated participant in the molecular pathology of PD is alpha-synuclein (α-syn). Mutations in, and multiplication of, the gene encoding α-syn result in inherited forms of PD. In addition, the presence of α-syn in Lewy bodies and neurites provides evidence for its association with idiopathic PD. A common hypothesis states that excess α-syn and consequent aggregation causes neurotoxicity in a direct toxic gain-of-function event. Conversely, it has also been proposed that α-syn aggregation may endanger neurons by removing the protein from its normal cellular location and diminishing its function in a toxic loss-of-function event. This issue remains a topic of debate. Despite this ambiguity, approaches that reduce α-syn in the central nervous system represent an active area of research as a strategy for treating PD. Our published data in rats and nonhuman primates, and preliminary data in mice, supports the dissenting viewpoint, showing that eliminating α-syn from mature dopamine (DA) neurons is not protective, but instead is toxic. Utilizing our newly developed conditional α-syn knock-out mouse, our proposed studies will define the consequences that result from ablated/decreased expression of α-syn in the nigrostriatal system. The use of rAAV to deliver CRE recombinase (iCRE) to dopamine neurons of adult mice carrying the floxed α- syn allele will allow us to efficiently abolish α-syn expression in mature neurons. This approach addresses the limitations of current germ-line mouse models by preventing the hypothesized compensatory adaptations that occur when α-syn expression is abolished during development. The following proposal will utilize this new mouse model to: 1) Characterize the pattern, timing, and α-syn dose-dependence of neurodegenerative effects on the nigrostriatal system and resultant impairment in motor behavior. 2) Define the characteristics of degeneration in its pattern and association with markers of cellular events previously implicated as participating in degeneration in PD (DA mishandling, oxidative/nitrative stress, proteasome/lysosome dysfunction, and microglial activation) at early and late stages of degeneration following removal of α-syn. This proposal will answer the lingering question of whether α-syn is crucial for the function and survival of mature DA neurons while also providing a new murine-based tool to study the importance of α-syn induced DA neurodegeneration for the study of synucleinopathies. The successful completion of these aims will advance our knowledge and ability to develop therapeutic strategies aimed at halting neurodegeneration due to α-syn dysfunction. Project Summary/Abstract Page 6