Pesticide-Mediated Generation of a Toxic Neurotransmitter Metabolite

项目摘要 暴露于有机氯狄氏剂使个体易患帕金森病（PD）;然而， 将暴露于疾病和多巴胺能细胞的选择性损失联系起来的机制是未知的。此外，本发明还提供了一种方法， 单独的狄氏剂可能不足以减少多巴胺（DA）神经元的损失，并且神经变性可能需要 额外的“命中”，例如来自遗传学。一些动物模型已经证明，改变DA代谢 和/或运输产生DA神经元的进行性损失;因此，修饰DA的遗传变异 代谢可能是与农药接触具有毒性协同作用的额外“打击”。除DA以外的细胞类型 神经元被认为与PD有关，如神经胶质，通过神经胶质激活释放的毒性因子被认为是PD的一部分。 被认为是疾病进展的关键因素。DA神经元和神经胶质细胞（例如，星形胶质细胞） 代谢DA和其他神经递质并产生有毒中间体，如ROS和醛类 （3，4-二羟基苯乙醛，DOPAL），通过单胺氧化酶。根据文献先例， 初步数据，我们提出DA代谢和贩运作为农药狄氏剂的机制目标 这会产生反应性和毒性中间体的积累，如DOPAL和神经炎症。而 DA及其醌作用已被探索为神经毒性的机制， DOPAL和醛代谢的作用。DOPAL生成被提出作为一种机制， 杀虫剂暴露、神经炎症和儿茶酚胺能细胞损失。这项工作的目标是阐明 神经退行性疾病环境风险因素的潜在机制，特别关注 农药狄氏剂与DArgic和神经胶质细胞的相互作用以及通过DArgic和神经胶质细胞对多巴胺能神经元的损伤 反应性中间体如DOPAL。此外，还将探讨基因-环境相互作用， 单独的狄氏剂可能不足以引起DA神经元的损失。核心假设是， 由于狄氏剂靶向神经元和神经胶质中的DA代谢和/或运输，产生反应性醛代谢物 损伤DA神经元并促进神经胶质细胞的神经炎性激活。三个目标将是 完成：1）确定农药暴露对转基因小鼠黑质-纹状体DA系统的影响 多巴胺代谢改变2)确定神经胶质衍生的反应性DA中间体对 农药介导的神经元损伤。3)识别活性中间体的细胞和分子靶点。一个 创新和全面的方法在体内和体外将使用一个强大的遗传策略的小鼠 缺乏或过度表达DA代谢关键酶的患者。这些具体目标将建立 在以前的工作，以解决关键的机制问题，关键细胞之间的相互作用， 星形胶质细胞和神经元，增强暴露于农药引起的功能障碍。

PROJECT SUMMARY Exposure to the organochlorine dieldrin predisposes individuals to Parkinson's Disease (PD); however, the mechanisms linking exposure to disease and selective loss of dopaminergic cells are unknown. In addition, dieldrin alone may be insufficient for loss of dopamine (DA) neurons, and neurodegeneration may require an additional “hit”, such as from genetics. Several animal models have demonstrated that altering DA metabolism and/or trafficking yields progressive loss of DA neurons; therefore, a genetic variation modifying DA metabolism may be an additional “hit” that has toxic synergy with pesticide exposure. Cell types other than DA neurons are thought to be involved in PD, such as glia, and toxic factors released via glial activation are realized as a critical contributors to disease progression. Both DA neurons and glial cells (e.g., astrocytes) metabolize DA and other neurotransmitters and generate toxic intermediates such as ROS and aldehydes (3,4-dihydroxyphenylacetaldehyde, DOPAL), via monoamine oxidase. Based on literature precedent and preliminary data, we propose DA metabolism and trafficking as a mechanistic target for the pesticide dieldrin that can produce a build-up of reactive and toxic intermediates such as DOPAL and neuroinflammation. While the role of DA and its quinone have been explored as a mechanism for neurotoxicity, very little is known about DOPAL and the role of aldehyde metabolism. DOPAL generation is proposed as a mechanism unifying pesticide exposure, neuroinflammation and loss of catecholaminergic cells. The goal of this work is to elucidate mechanisms underlying environmental risk factors for neurodegenerative disease, specifically focusing on the interaction of the pesticide dieldrin with DArgic and glia and resulting injury to dopaminergic neurons via reactive intermediates such as DOPAL. In addition, the gene-environment interaction will be explored as dieldrin alone may be insufficient to cause loss of DA neurons. The central hypothesis is that pesticides such as dieldrin target DA metabolism and/or trafficking in neurons and glia, yielding reactive aldehyde metabolites that damage DA neurons and promote neuroinflammatory activation of glial cells. Three Aims will be completed: 1) Determine the effects of pesticide exposure on the nigro-striatal DA system in transgenic mice with altered DA metabolism. 2) Determine the contribution of glial-derived reactive DA intermediates to pesticide-mediated neuronal injury. 3) Identify cellular and molecular targets of reactive intermediates. An innovative and encompassing approach in vivo and in vitro will be used with a robust genetic strategy of mice that are deficient or have overexpression of enzymes key to DA metabolism. These Specific Aims will build upon previous work to address key mechanistic questions regarding critical cellular interactions between astrocytes and neurons that potentiate dysfunction caused by exposure to pesticides.