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

α-突触核蛋白对于神经元功能和生存至关重要 - 新型条件性 α-突触核蛋白敲除小鼠模型的表征

• 批准号: 9224008
• 负责人: Fredric Manfredsson
• 金额: $ 23.25万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-30 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9224008
• 关键词: Ablation; Address; Adult; Alleles; Animal Model; Area; Behavior; Brain; Cell physiology; Characteristics; Corpus striatum structure; Data; Denervation; Dependence; Dependovirus; Development; Dissent; Dopamine; Dose; Enterobacteria phage P1 Cre recombinase; Etiology; Event; Excision; Face; Financial compensation; Foundations; Functional disorder; Future; Generations; Genes; Genetic; Germ Lines; Homeostasis; Idiopathic Parkinson Disease; Impairment; Inherited; Knock-out; Knockout Mice; Knowledge; Lewy Bodies; Location; LoxP-flanked allele; Lysosomes; Mediating; Mediator of activation protein; Midbrain structure; Mitotic; Modeling; Molecular; Motor; Mus; Mutation; Nerve Degeneration; Neuraxis; Neurites; Neurons; Oxidative Stress; Parkinson Disease; Participant; Pattern; Phenotype; Population; Process; Proteins; Published Comment; Publishing; Rattus; Reactive Oxygen Species; Recombinant adeno-associated virus (rAAV); Research; Role; SNCA gene; Silent Mutation; Staging; Stress; Substantia nigra structure; Supplementation; Synapses; Therapeutic; Therapeutic Human Experimentation; Time; Tissues; Toxic effect; alpha synuclein; base; dopaminergic neuron; functional loss; gain of function; improved; knock-down; knockout animal; loss of function; molecular pathology; mouse model; multicatalytic endopeptidase complex; neurotoxicity; nigrostriatal system; nonhuman primate; novel; overexpression; oxidation; presynaptic; prevent; recombinase; research study; small hairpin RNA; synucleinopathy; tool

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.

项目摘要 我们目前对帕金森病（PD）的分子病因学的理解是不完整的， 可能是多种因素相互作用的结果。PD分子病理学中最有效的参与者 是α-突触核蛋白（α-syn）。编码α-syn的基因的突变和增殖导致遗传形式 的PD。此外，α-syn在路易体和神经突中的存在提供了证据，表明它与神经元凋亡有关。 特发性帕金森病一种常见的假设认为，过量的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，也有人提出α-syn 聚集可能通过将蛋白质从其正常的细胞位置移除并减少细胞中的蛋白质而危及神经元。 其在毒性功能丧失事件中的功能。这个问题仍然是一个辩论的主题。尽管存在这种模糊性， 减少中枢神经系统中α-syn的方法是一个活跃的研究领域， 治疗帕金森病我们发表的大鼠和非人灵长类动物的数据，以及小鼠的初步数据，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不是保护性的， 反而是有毒的。利用我们新开发的条件性α-syn基因敲除小鼠，我们的研究将 定义黑质纹状体系统中α-syn表达的消除/减少所导致的后果。 使用rAAV将CRE重组酶（iCRE）递送至携带floxed α- syn等位基因将允许我们有效地消除成熟神经元中的α-syn表达。这种方法解决了 通过阻止假设的代偿性适应， 当α-syn表达在发育过程中消失时发生。以下建议将利用这一新的 小鼠模型：1）表征神经退行性作用的模式、时间和α-syn剂量依赖性 对黑质纹状体系统的影响以及由此导致的运动行为障碍。2)定义的特征 其模式的退化以及与先前涉及参与的细胞事件的标记物的关联 在PD的变性（DA处理不当，氧化/硝化应激，蛋白酶体/溶酶体功能障碍， 小胶质细胞活化）。 这一提议将回答一个挥之不去的问题，即α-syn是否对细胞的功能和生存至关重要。 同时也为研究α-syn诱导DA的重要性提供了一种新的基于小鼠的工具 用于研究突触核蛋白病的神经变性。这些目标的成功实现将推动 我们的知识和能力，以制定治疗策略，旨在停止神经退行性变，由于α-syn 功能障碍