Nuclear integration of environmental toxic signals relevant to PD

描述（由申请人提供）：帕金森病（PD）涉及神经元的病理性丧失。本研究的长期目标是了解环境和遗传神经毒性药物如何相互作用，以信号和调节PD发病机制中的生存/凋亡机制。我们最近的一系列研究结果强调了细胞周期蛋白依赖性激酶5（CdkS）介导的生存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，我们在本申请中提出探索核Cdk5-MEF2通路在介导和整合PD相关环境毒物和遗传风险因子的毒性信号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，评估细胞核Cdk 5介导的MEF 2调节在环境毒物诱导的多巴胺能神经元变性中的作用; 2.确定细胞核Cdk5-MEF2通路在帕金森病动物模型中的神经毒性诱导的神经元损失中的作用;和3.建立PD遗传模型中CDk5-MEF2通路在整合环境毒物和α-突触核蛋白的神经毒性信号中的作用。为了实现目标MII，我们将在多巴胺能神经元细胞系SN 4741细胞、原代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，以研究核Cdk 5活性的失调和MEF 2存活促进功能的丧失是否是多巴胺能神经元响应于环境毒物而死亡的基础。我们将试图建立是否核Cdk5-MEF2介导的α-synculein毒性遗传模型的PD发病机制和研究如何有毒的α-突触核蛋白相互作用影响这一关键的信号通路。我们将在拟议的研究中使用形态学，生物化学，分子生物学，功能/行为和遗传学方法的组合。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质，并作为毒物-α-突触核蛋白相互作用的毒性作用的关键汇聚点。从这项研究中获得的这一新的见解将证明环境毒物和遗传风险因素如何会聚并破坏生存途径，提供可能导致与散发性和家族性PD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.