Nuclear integration of environmental toxic signals relevant to PD

描述(申请人提供)：帕金森氏病(PD)涉及神经元的病理性丢失。我们实验室这项研究的长期目标是了解环境和遗传神经毒剂如何相互作用，在帕金森病发病机制中发出信号并调节生存/凋亡机制。我们最近的一系列发现强调了核周期蛋白依赖激酶5(CDKs)介导的对存活因子肌细胞增强因子2(MEF2)的抑制在神经元存活和凋亡中的关键作用。基于此，我们建议在本应用中探讨核CDK5-MEF2通路在介导和整合PD相关环境毒物的毒性信号和遗传危险因素在多巴胺神经元变性中的作用。我们的具体目标是：1.在帕金森病细胞模型中，评估核CDK5介导的MEF2调节在环境毒物诱导的多巴胺能神经元变性中的作用；2.确定核CDK5-MEF2通路在环境毒物诱导的帕金森病动物模型神经元丢失中的作用；3.确定CDK5-MEF2通路在整合环境毒物的神经毒性信号和α-突触核蛋白在帕金森病遗传模型中的作用。为了达到MIL的目的，我们将在多巴胺能神经元细胞系SN4741细胞、原代培养的多巴胺神经元和啮齿动物/转基因小鼠中测试一组模型毒物，包括MPP+(MPTP的代谢物)、鱼藤酮和百草枯，以探讨核CDK5活性的下调和MEF2存活促进功能的丧失是否是环境毒物导致多巴胺能神经元死亡的基础。我们将试图在帕金森病发病的遗传模型中建立核CDK5-MEF2是否介导α-突触蛋白毒性，并研究毒物-α-突触核蛋白相互作用如何影响这一关键信号通路。在拟议的研究中，我们将综合使用形态、生化、分子生物学、功能/行为和遗传学方法。我们的研究将使我们能够确定核CDK5-MEF2通路是否是环境毒物诱导的多巴胺神经元凋亡的主要介导者，以及是否作为毒物-α-突触核蛋白相互作用毒性效应的关键汇聚点。从这项研究中获得的这一新见解将展示环境毒物和遗传风险因素如何聚合并扰乱生存途径，提供可能导致与散发性和家族性帕金森病相关的多巴胺神经元丢失的分子机制。

DESCRIPTION (provided by applicant): Parkinson's disease (PD) involves pathological loss of neurons. The long-term objective of this research in our laboratory is to understand how environmental and genetic neurotoxic agents interact to signal and regulate the survival/apoptosis machinery in PD pathogenesis. A series of our recent findings highlight the key role of nuclear cyclin dependent kinase 5 (CdkS)-mediated inhibition of survival factor myocyte enhancer factor 2 (MEF2) in neuronal survival and apoptosis. Based on this, we propose in the present application to explore the role of nuclear Cdk5-MEF2 pathway in mediating and integrating the toxic signals of PD relevant environmental toxicants and genetic risk factors in the degeneration of dopamine neurons. Our specific aims are: 1. to assess the role of nuclear Cdk5-mediatd regulation of MEF2 in environmental toxicant-induced degeneration of dopaminergic neruosn in cellular models of PD; 2. to determine the role of nuclear Cdk5- MEF2 pathway in environmemntal toxicant-induced neuronal loss in animal models of PD; and 3. to establish the role of CDk5-MEF2 pathway in integrating neurotoxic signals of environmental toxicants and alpha- synuclein in genetic models of PD. To accomplish aim Mil, we will test a group of model toxicants including MPP+(metabolite of MPTP), rotenone, and paraquat in dopaminergic neuronal cell line SN4741 cells, primary dopamine neurons, and rodents/transgenic mice to investigate whether de-regulation of nuclear Cdk5 activiy and loss of MEF2 survival promoting function underlie the demise of dopaminergic neurons in response to environmental toxicants. We will attempt to establish whether nuclear Cdk5-MEF2 mediates alpha-synculein toxicity in genetic models of PD pathogenesis and study how toxicant-alpha-synuclein interaction affects this critical signaling pathway. We will use a combination of morphological, biochemical, molecular biological, functional/behavioral and genetic methods in the proposed study. Our studies will allow us to determine whether nuclear Cdk5-MEF2 pathway is a major mediator of environmental toxicant-induced apoptosis of dopamine neurons and functions as a key converging point for the toxic effect of toxicant-alpha- synuclein interaction. This novel insight gained from this study will demonstrate how environmental toxicants and genetic risk factors may converge and disrupt a survival pathway, providing a molecular mecahnism that may underlie loss of dopamine neurons relevant to both sporadic and familial PD.