Novel Molecular Genetic Approaches for the Prevention and Treatment of Parkinsons

描述（由申请人提供）：帕金森病（PD）是一种由中脑多巴胺神经元变性引起的运动障碍。然而，这些细胞的亚群在PD和PD动物模型中相对较少-从内侧腹侧被盖区（VTA）投射到腹内侧纹状体（VMS或内侧壳核）的那些。该投射还包含许多表达囊泡谷氨酸转运体（VGLUT 2）并共同释放兴奋性神经递质谷氨酸的多巴胺神经元。由于VGLUT 2和囊泡单胺转运蛋白（VMAT 2）似乎定位于VMS中突触囊泡的重叠群体，谷氨酸的囊泡共进入可能通过增加囊泡pH梯度（DpH）来赋予神经保护作用。然后预测较大的DpH将增加多巴胺的囊泡储存，用于将多巴胺和其他潜在的细胞毒性VMAT 2底物隔离到囊泡体中，在囊泡体中它们的毒性被减轻。该提案的第一个目的是使用选择性条件性敲除小鼠和病毒表达策略测试VGLUT 2是否在PD的MPTP损伤模型中赋予神经保护益处。在PD或PD损伤模型中多巴胺神经元的损失之后，来自基底神经节中的多巴胺感受介质多刺神经元（MSN）的输出失调。特别是，含有间接途径的MSN的多巴胺D2受体的过度激活和随后的丘脑底核的过度兴奋似乎是与PD相关的最严重的运动症状的原因。因此，我们将测试是否翻转极性的间接通路输出从抑制性到兴奋性可以恢复运动行为在PD病变模型。这些研究将测试新的假设和一个新的分子靶点（VGLUT 2）在神经回路，有助于PD。这项工作将提供有关这些回路对兴奋性递质释放变化的可塑性的重要信息，并可能导致治疗和预防帕金森病的新方法。

DESCRIPTION (provided by applicant): Parkinson's Disease (PD) is a motor disorder brought on by neurodegeneration of midbrain dopamine neurons. However, a subpopulation of these cells is relatively spared both in PD and in PD animal models - those that project from the medial ventral tegmental area (VTA) to the ventromedial striatum (VMS or the medial shell of the nucleus accumbens). This projection also contains many dopamine neurons that express the vesicular glutamate transporter (VGLUT2) and co-release the excitatory neurotransmitter glutamate. Because VGLUT2 and the vesicular monoamine transporter (VMAT2) appear to localize to an overlapping population of synaptic vesicles in the VMS, the vesicular co-entry of glutamate may confer neuroprotection by increasing the vesicular pH gradient (DpH). Larger DpH would then be predicted to increase the vesicular storage of dopamine, serving to sequester dopamine and other potentially cytotoxic VMAT2 substrates into vesicular bodies where their toxicity is mitigated. The first aim of this proposal will test whether VGLUT2 confers neuroprotective benefits in an MPTP lesion model of PD using selective conditional knockout mice and viral expression strategies. Following the loss of dopamine neurons in PD or PD lesion models, output from the dopaminoceptive medium spiny neurons (MSN) in the basal ganglia is dysregulated. In particular, over-activation of the dopamine D2 receptor containing MSNs of the indirect pathway and consequent over-excitation of the subthalamic nucleus appear to account for the most severe motor symptoms associated with PD. We will thus test whether flipping the polarity of indirect pathway output from inhibitory to excitatory can restore motor behaviors in a PD lesion model. These studies will test novel hypotheses and a new molecular target (VGLUT2) in the neural circuitry that contribute to PD. The work will provide important information about the plasticity of these circuits to changes in excitatory transmitter release, an may lead to new approaches for the treatment and prevention of Parkinson's Disease.