Focal Dopamine Indicated in Dyskinesias in MPTP Monkeys

描述（由申请人提供）：本提案的主要目的是检验以下假设：帕金森病（PD）中L-多巴诱导的运动障碍（LID）至少部分源于纹状体的非均匀多巴胺能去神经支配，由此在纹状体最严重受影响的部分（连合后壳核）内产生多巴胺能活性岛（热点）。用含有芳香族L-氨基酸脱羧酶（AADC）的cDNA的AAV转导，纹状体神经元获得从外源性L-多巴（DA前体）产生多巴胺（DA）的能力。在PD的非人灵长类动物（NHP）模型中的测试期间，当以产生高AADC活性的局灶性区域的方式将AAV-AADC输注到纹状体中时，我们观察到严重的LID。最近，我们发现，在一只帕金森病猴的连合后壳核中产生一个单一的AADC热点产生了LID，这是值得注意的，因为这个模型几乎完全对LID不敏感。我们计划使用一种诱导型AADC表达载体，该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，我们应该能够在猴子大脑中可逆地产生热点。这反过来又使我们能够问，打开和关闭AADC热点是否与LID的诱导和减轻相关。我们还将能够询问LID发作时发生了什么样的代谢和分子变化，以及这些变化是否在热点消除后逆转。这项研究计划从三个角度来看是重要的。首先，它承诺建立一个在体内模型的LID中，神经相关的LID可以在一个受控的设置进行调查。第二，它试图测试有关L-多巴依赖性运动障碍的机制和解剖学起源的重要假设。最后，它调查了移植后运动障碍的两个可能原因，这可能是目前PD移植治疗进展的最重要障碍。这项工作将提供深入了解背后的机制左旋多巴诱导运动障碍，并将提供一个基础，使用基因治疗方法来治疗帕金森氏病患者。

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.