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验证一种假设，即帕金森病（PD）中l -多巴诱导的运动障碍（LID）至少部分是由纹状体的不均匀多巴胺能失神经支配引起的，在纹状体中受影响最严重的部分，即交后壳核中产生了多巴胺能活动岛（热点）。在含有芳香L-氨基酸脱羧酶（AADC） cDNA的AAV转导下，纹状体神经元获得了从外源L-多巴（DA前体）产生多巴胺（DA）的能力。在非人灵长类动物（NHP） PD模型的测试中，我们观察到当AAV-AADC以一种产生高AADC活性的焦点区域的方式注入纹状体时，严重的LID。最近，我们发现在半帕金森猴的接触后壳核中产生单个AADC热点产生LID，值得注意的是，该模型几乎完全不耐受LID。我们计划使用一种诱导型AADC表达载体，该载体最近在帕金森病啮齿动物模型中被证明是有效的。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。反过来，这应该允许我们询问打开和关闭AADC热点是否与LID的诱导和减弱相关。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，以及热点消除后这些变化是否会逆转。这个研究项目的重要性体现在三个方面。首先，它有望建立一个LID的体内模型，其中LID的神经相关因素可以在受控环境下进行研究。其次，它试图测试关于左旋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。这项工作将为左旋多巴诱导的运动障碍背后的机制提供见解，并将为使用基因治疗方法治疗帕金森病患者提供基础。

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.