Axon Guidance Molecules in Nigrostriatal Regeneration

描述(由申请人提供)：我们对帕金森病中退化的多巴胺能(DA)黑质纹状体(NS)通路的重建策略感兴趣，这是一个重要的目标，因为目前的长期治疗不足。通过将前体细胞或神经元移植到成人黑质重建这一通路的尝试失败了，可能是由于1)抑制分子的存在和/或2)成人中枢神经系统中缺乏营养和引导分子。在这里，我们认为，对调节黑质纹状体通路发展的分子事件的理解将为设计改善成人环境中NS通路再生的策略提供见解。我们提出--并有令人兴奋的初步数据支持--轴突引导分子(AGM)是指导中枢神经系统其他投射通路发展的重要分子，在发育中的DA NS通路中表达。一系列的实验被用来阐明AGMs及其受体在NS途径的发展中所起的作用。我们的具体目标是：1)明确其受体在黑质DA神经元发育中的轴突表达的AGM；2)确定与发育中的NS通路相关的AGM配体的表达；3)对于那些在适当的解剖关系中表达影响NS发育的AGM，其受体表达于发育中的DA神经元，在体外直接证明其对胎儿黑质DA神经元的趋化作用，并通过体外阻断研究它们在NS通路发育中的重要性。这项提案中概述的实验结果有望改进方法，以对抗成人受损神经系统的抑制环境，并概括指导发育过程中轴突生长的吸引和排斥因素，从而为改善帕金森氏症症状的新的重建和再生策略铺平道路。从这些研究中得出的见解也可能适用于其他神经退行性疾病、脑损伤和中风。概述的研究是为首席调查员定制的培训和职业发展五年计划的一部分。该建议包括由经验丰富的科学家进行积极指导，获得各种资源，以及一个独特的环境，以帮助PI发展为独立的神经外科医生-神经科学家。

DESCRIPTION (provided by applicant): We are interested in developing strategies for the reconstitution of the dopaminergic (DA) nigrostriatal (NS) pathway that degenerates in Parkinson's disease, an important goal because of the inadequacy of current long-term treatments. Attempts to reconstruct this pathway through transplantation of precursor cells or neurons into the nigra of the adult fail, likely as a result of 1) the presence of inhibitory molecules and/or 2) the absence of trophic and guidance molecules in the adult CNS. Here we propose that an understanding of the molecular events that regulate the development of the nigrostriatal pathway will provide insights for strategies designed to improve NS pathway regeneration in the adult milieu. We propose - and have exciting preliminary data to support - that axon guidance molecules (AGMs), important molecules that direct the development of other projection pathways in the CNS, are expressed in the developing DA NS pathway. A series of experiments are proposed to elucidate the role played by AGMs and their receptors in the development of the NS pathway. Our specific aims are to: 1) Define those AGMs whose receptors are expressed in the developing axons of nigral DA neurons; 2) Define the expression of AGM ligands in relation to the developing NS pathway; 3) For those AGMs that are expressed in an appropriate anatomical relationship to influence NS development, and whose receptors are expressed in developing DA neurons, directly demonstrate chemotropic effects on fetal nigral DA neurons in vitro, and their importance in the development of the NS pathway with blocking studies ex vivo. The outcome of the experiments outlined in this proposal will hopefully be the refinement of means to counteract the inhibitory milieu of the adult injured nervous system, and recapitulate the attractive and repulsive factors that direct axonal outgrowth during development, thereby paving the way for novel reconstructive and regenerative strategies to ameliorate the symptoms of Parkinson's disease. The insights derived from these studies may also have applicability in other neurodegenerative diseases, brain injury and stroke. The research outlined is part of a customized five-year plan of training and career development for the Principal Investigator. The proposal includes active mentoring by experienced scientists, access to diverse resources, and an environment uniquely suited to help the PI develop as an independent neurosurgeon-neuroscientist.