Vesicular modulation of dopamine neuron toxicity

摘要 米勒实验室两年多以来一直在研究神经元中多巴胺的不同性质 几十年。多巴胺是一种重要的神经递质/神经调节剂，但同时它也代表了一种 内源性毒性的潜在来源。我们实验室和其他实验室的数据清楚地表明 多巴胺储存不当，通过改变囊泡单胺转运蛋白（VMAT2）的功能，可以诱导 进行性黑质纹状体多巴胺神经变性，与特发性帕金森病极为相似。 因此，多巴胺的合成、包装和降解（即稳态）受到严格调节，以尽量减少 潜在的毒性。在之前的资助期间，该实验室提供了第一个证据表明突触 囊泡糖蛋白 2C (SV2C) 是囊泡多巴胺稳态的关键调节剂。我们证明了 SV2C 调节突触多巴胺释放，其表达在人类帕金森病大脑中发生改变 组织。 2020年4月另一实验室在大型帕金森病GWAS中鉴定出SV2C，牢牢定位 该蛋白质在帕金森病发病机制中发挥着关键作用。我们实验室的新初步数据 表明 SV2C 可以赋予 MPTP 抗性，并防止多巴胺从囊泡中渗漏。 这些数据作为我们假设的基础，即 SV2C 通过其在突触内保留多巴胺的能力 囊泡，赋予对多巴胺神经毒性的抵抗力。我们将通过以下具体内容来检验这一假设 目标：目标 1，检查 SV2C 调节囊泡多巴胺稳态的机制和 介导毒物引起的神经毒性。目标2，确定是否引入进化先进的 将 SV2 蛋白注入模型生物线虫中可以提供针对多巴胺能毒性的保护作用。目标3， 确定小鼠中 SV2C 的功能特性。目标 4，确定 SV2C 在 PD 相关中的作用 小鼠的发病机制（基于突触核蛋白和毒物诱导）。完成上述具体目标将提供 关于 SV2C 在多巴胺神经元功能中的作用、对化学物质的脆弱性的关键信息 帕金森病的发展及其作为治疗干预目标的潜力。

Abstract The Miller laboratory has been conducting research on the divergent nature of dopamine in neurons for over two decades. Dopamine is an essential neurotransmitter/neuromodulator, but at the same time it represents a potential source of endogenous toxicity. Data from our laboratory and others have clearly demonstrated that improperly stored dopamine, via altered function of the vesicular monoamine transporter (VMAT2) can induce progressive nigrostriatal dopamine neurodegeneration that is strikingly similar to idiopathic Parkinson’s disease. The synthesis, packaging, and degradation of dopamine (i.e. homeostasis) is thus tightly regulated to minimize the potential for toxicity. In the previous funding period, the laboratory provided the first evidence that the synaptic vesicle glycoprotein 2C (SV2C) was a key modulator of vesicular dopamine homeostasis. We demonstrated that SV2C regulates synaptic dopamine release and its expression is altered in human Parkinson’s disease brain tissue. In April, 2020 another laboratory identified SV2C in a large Parkinson’s disease GWAS firmly positioning the protein as a key player in Parkinson’s disease pathogenesis. New preliminary data from our laboratory indicate that SV2C can confer resistance to MPTP and that it prevents leakage of dopamine from the vesicle. These data serve as the basis of our hypothesis that SV2C, through its ability to retain dopamine within synaptic vesicles, confers resistance to dopamine neurotoxicity. We will test this hypothesis through the following specific aims: Aim 1, to examine the mechanisms by which SV2C regulates vesicular dopamine homeostasis and mediates toxicant-induced neurotoxicity. Aim 2, to determine whether introducing the evolutionarily advanced SV2 proteins into the model organism C. elegans can confer protection against dopaminergic toxicity. Aim 3, to determine the functional properties of SV2C in mice. Aim 4, to determine the role of SV2C in PD-related pathogenesis (synuclein-based and toxicant-induced) in mice. Completion of the above specific aims will provide critical information on the role of SV2C in dopamine neuron function, vulnerability to chemicals suspected in the development of Parkinson’s disease, and its potential as a target of therapeutic intervention.