Vesicular modulation of dopamine neuron toxicity

多巴胺神经元毒性的囊泡调节

• 批准号: 9522240
• 负责人: GARY W MILLER
• 金额: $ 2.44万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-11-17 至 2019-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9522240
• 关键词: Address; Aldehydes; Animals; Bacterial Artificial Chromosomes; Behavior; Brain; Brain Diseases; Corpus striatum structure; Data; Development; Disease; Dopamine; Electrochemistry; Foundations; Functional disorder; Gene Mutation; Genetic; Glycoproteins; Gold; Histology; Human; Individual; Knock-out; Laboratories; Levodopa; Literature; Measures; Mediating; Microdialysis; Modeling; Motor; Mus; Nerve Degeneration; Neurons; Neurotoxins; Neurotransmitters; Parkinson Disease; Pathogenesis; Pathology; Periodicity; Play; Polychlorinated Biphenyls; Process; Resistance; Rotenone; Scanning; Signal Transduction; Slice; Substantia nigra structure; Synaptic Vesicles; System; Techniques; Testing; Toxic effect; Toxicogenetics; Transgenic Mice; Vesicle; aged; alpha synuclein; base; dopamine system; dopaminergic neuron; environmental chemical; genetic manipulation; improved functioning; in vivo; innovation; motor deficit; neurochemistry; neuropathology; neuroprotection; neurotoxicity; novel; novel strategies; novel therapeutic intervention; optogenetics; overexpression; pars compacta; prevent; public health relevance; standard care; theories; uptake; vesicular release

DESCRIPTION (provided by applicant): A major feature of Parkinson's disease (PD) is the loss of dopamine-producing neurons in the substantia nigra pars compacta and the concomitant loss of dopamine in the striatum. While multiple processes likely contribute to the loss of dopamine neurons, we argue that disruption of the proper storage and release of dopamine from vesicles plays a key role. This theory is supported by the literature, which demonstrates that improper storage of dopamine causes the formation of oxidative dopamine byproducts and toxic aldehydes that damages neurons. Evidence from genetic and toxicological studies of PD demonstrates that many insults converge on the dopamine vesicle to exert their deleterious effects. We hypothesize that vesicular function mediates dopamine neuron toxicity, such that increasing vesicle function will enhance dopamine storage and release and confer resistance to neurotoxicants, while decreasing vesicle function will have the opposite effect. Our laboratory has generated and characterized two unique mouse lines that allow us to test this hypothesis: a bacterial artificial chromosome-based transgenic mouse that overexpresses VMAT2 (VMAT2-HI) and a genetic knockout of the synaptic vesicle glycoprotein 2C (SV2C-KO), which was recently implicated in Parkinson's disease pathogenesis. Here, we provide preliminary data that clearly demonstrate that increased vesicular function is beneficial to the dopamine system and that SV2C is a novel regulator of dopamine uptake and release. Together, these findings provide the basis for the following aims. Aim 1: To determine the effects of variable VMAT2 or SV2C expression on vesicular dopamine storage and release dynamics. We will determine how these genetic manipulations alter vesicular dynamics, including the readily releasable pool. Aim 2: To determine if altered vesicular storage and release alters vulnerability of dopamine neurons in a model of PD. We determine the effect of reduced SV2C or increased VMAT2 on MPTP toxicity in aged mice, a classical and well-established model. Aim 3: To determine if altered vesicular storage and release of dopamine influences vulnerability to the PD-related toxicity of polychlorinated biphenyls (PCBs). We expect that our mice will show an inverse correlation between vesicle function and PCB-induced. In addition to the novel mouse lines generated in our laboratory we will use a suite of cutting-edge techniques in our studies, including optogenetic stimulation, fast-scan cyclic voltammetry, in vivo microdialysis, and CLARITY. Completion of these aims will establish a pivotal concept in neuroprotection: increasing vesicle function improves neurotransmitter signaling and opposes dopamine neuron toxicity. This suggests that modulation of synaptic vesicle function represents an innovative and unexplored opportunity for addressing dopamine neuron dysfunction and provides a foundation for new therapeutic approaches.

描述（由申请人提供）：帕金森病（PD）的一个主要特征是黑质致密部中产生多巴胺的神经元的丧失以及纹状体中多巴胺的伴随丧失。虽然多个过程可能导致多巴胺神经元的损失，但我们认为，囊泡中多巴胺的适当储存和释放的破坏起着关键作用。这一理论得到了文献的支持，文献表明多巴胺储存不当会导致氧化多巴胺副产物和有毒醛的形成，从而损害神经元。 PD 遗传和毒理学研究的证据表明，许多损伤聚集在多巴胺囊泡上，发挥其有害作用。我们假设囊泡功能介导多巴胺神经元毒性，因此增加囊泡功能将增强多巴胺的储存和释放并赋予对神经毒物的抵抗力，而降低囊泡功能将产生相反的效果。我们的实验室已经培育并鉴定了两种独特的小鼠品系，使我们能够检验这一假设：一种基于细菌人工染色体的转基因小鼠，其过度表达 VMAT2 (VMAT2-HI) 和基因敲除突触小泡糖蛋白 2C (SV2C-KO)，后者最近与帕金森病的发病机制有关。在这里，我们提供了初步数据，清楚地证明囊泡功能的增加有利于多巴胺系统，并且 SV2C 是多巴胺摄取和释放的新型调节剂。这些发现共同为以下目标提供了基础。目标 1：确定可变 VMAT2 或 SV2C 表达对囊泡多巴胺储存和释放动力学的影响。我们将确定这些基因操作如何改变囊泡动力学，包括易于释放的池。目标 2：确定改变的囊泡储存和释放是否会改变 PD 模型中多巴胺神经元的脆弱性。我们确定了 SV2C 减少或 VMAT2 增加对老年小鼠 MPTP 毒性的影响，这是一个经典且完善的模型。目标 3：确定改变囊泡储存和多巴胺释放是否会影响多氯联苯 (PCB) 与 PD 相关的毒性的脆弱性。我们预计我们的小鼠将表现出囊泡功能与 PCB 诱导之间的负相关性。除了我们实验室产生的新型小鼠品系外，我们还将在研究中使用一套尖端技术，包括光遗传学刺激、快速扫描循环伏安法、体内微透析和 CLARITY。这些目标的完成将建立神经保护的关键概念：增加囊泡功能可改善神经递质信号传导并对抗多巴胺神经元毒性。这表明突触小泡功能的调节代表了解决多巴胺神经元功能障碍的创新和未经探索的机会，并为新的治疗方法提供了基础。