Focal Dopamine Indicated in Dyskinesias in MPTP Monkeys

描述(申请人提供)：这项建议的广泛目标是检验一种假设，即L-多巴诱导的帕金森病(PD)运动障碍(LID)至少部分是由于纹状体受影响最严重的部分，即连合后壳核，产生多巴胺能神经失神经，从而产生多巴胺能活动岛(热点)。在转导含有芳香L氨基酸脱羧酶基因的腺病毒载体后，纹状体神经元能够从外源性的L-多巴(DA)前体产生多巴胺(DA)。在非人类灵长类(NHP)PD模型的测试中，我们观察到当AAV-AADC以产生高AADC活动的焦点区域的方式注入纹状体时，严重的LID。最近，我们发现，在偏侧帕金森病猴的连合后壳核中，单个AADC热点的产生产生了LID，值得注意的是，这个模型几乎完全不适用于LID。我们计划使用可诱导的AADC表达载体，最近被证明在帕金森病啮齿动物模型中有效。有了这个工具，我们应该能够可逆地在猴子的大脑中产生热点。这反过来又让我们可以问，打开和关闭AADC热点是否与LID的诱导和减少有关。我们还将能够询问LID发生时会发生什么样的代谢和分子变化，以及这种变化在热点消除后是否会逆转。从三个角度来看，这一研究计划具有重要意义。首先，它承诺建立LID的体内模型，在该模型中，LID的神经关联可以在受控环境中进行研究。其次，它试图检验关于L-多巴依赖型运动障碍的机制和解剖学起源的重要假说。最后，它调查了植入后运动障碍的两个可能的原因，这可能是目前阻碍基于移植的帕金森病治疗进展的最重要的原因。这项工作将为深入了解L-多巴诱发运动障碍的机制提供依据，并将为使用基因治疗方法治疗帕金森氏症患者提供基础。

DESCRIPTION (provided by applicant): The broad aim of this proposal is to test the hypothesis that L-dopa-induced dyskinesias (LID) in Parkinson's disease (PD) arise at least in part from non-uniform dopaminergic denervation of the striatum, whereby islands of dopaminergic activity (hotspots) are created within the most severely affected part of the striatum, the post-commissural putamen. Transduced with an AAV containing the cDNA for aromatic L- amino acid decarboxylase (AADC), striatal neurons gain the ability to produce dopamine (DA) from exogenous L-Dopa, a DA precursor. During testing in a non-human primate (NHP) model of PD, we observed severe LID when AAV-AADC was infused into the striatum in a way that generated focal regions of high AADC activity. More recently, we have found that the generation of a single AADC hotspot in the post-commissural putamen of a hemi-parkinsonian monkey generated LID, remarkable because this model is almost completely refractory to LID. We plan to use an inducible AADC expression vector, recently shown to be effective in a parkinsonian rodent model. With this tool, we should be able to produce hotspots in monkey brain reversibly. This in turn should allow us to ask whether turning AADC hotspots on and off correlates with induction and abatement of LID. We will also be able to ask what kinds of metabolic and molecular changes occur with onset of LID, and whether such changes are reversed upon elimination of the hotspot. This research program is important from three perspectives. First, it promises to establish an in vivo model of LID in which neural correlates of LID can be investigated in a controlled setting. Second, it seeks to test important hypotheses regarding the mechanistic and anatomical origins of L-Dopa-dependent dyskinesias. Finally, it investigates two likely causes of post-engraftment dyskinesias, which are perhaps the most important current impediment to progress in transplantation-based therapies for PD. This work will provide insight on the mechanisms behind L-dopa induced dyskinesias and will provide a basis for using gene therapy approaches to treat patients with Parkinson's disease.