Dopamine Neuron VGLUT2 Expression in Parkinson's Disease

项目摘要 在帕金森氏病（PD）中，黑质腹侧部（SNc）中的多巴胺（DA）神经元退化。 相比之下，腹侧被盖区（VTA）的DA神经元相对受到PD诱导的保护。 变性，但这种神经保护的原因是未知的。一个可能的答案可能来自于 腹侧被盖区DA神经元的特性：这些细胞的一个子集共同释放谷氨酸并表达囊泡谷氨酸 转运蛋白2（VGLUT 2）。表达VGLUT 2的DA神经元更可能在动物神经毒性损伤中存活 在PD和DA神经元模型中，在对DA神经毒素有弹性的神经元中观察到VGLUT 2上调。 值得注意的是，在果蝇、啮齿类动物、非人类和哺乳动物的DA神经元中VGLUT 2表达上调。 人类灵长类动物对细胞应激的反应，这表明这是一种进化上保守的机制， 赋予对DA神经元变性的保护。此外，在果蝇中，我发现雌性表达的 果蝇VGLUT（dVGLUT）与雄性相比。我还发现雄性果蝇明显更容易受到DA的影响 神经元变性并在PD的DA神经毒素模型中表现出比雌性更多的运动缺陷[例如， 百草枯和6-羟基多巴胺（6 OHDA）]类似于人类PD的性别特异性后遗症。这些 研究结果表明，VGLUT 2表达可能是保护这些细胞的调节机制的一部分 这可能会影响PD的性别差异。这些数据还表明，遗传上易于处理的苍蝇模型可以 作为一个强大的实验系统来研究DA神经元的弹性和脆弱性机制 在警局鉴于VGLUT在DA神经元弹性中的作用，本提案的中心目标是确定：1） DA神经元VGLUT表达如何影响DA神经元的脆弱性，2） DA神经元弹性依赖于DA神经元VGLUT表达的差异，以及3）DA神经元如何 人PD中的VGLUT 2表达变化。我将检验DA神经元VGLUT表达 赋予DA神经元增加的保护，特别是在女性中，因为它们表达更多的VGLUT 与男性相比。本提案的长期目标是：（一）确定VGLUT在调解 在蝇类模型中对6-羟多巴胺和百草枯的敏感性和性别差异（目标1），以及ii）衡量 人PD中DA神经元VGLUT 2的表达（目的2）。为了测试这些目标，我将使用RNA干扰来敲 在果蝇DA神经元中下调dVGLUT表达，并测量雄性与 6 OHDA和百草枯PD模型中的雌蝇。与此同时，我将测量DA神经元VGLUT 2的表达， 使用男性和女性PD患者和匹配对照的死后人中脑的人PD。这些 实验将确定DA神经元VGLUT表达作为PD中神经保护的新机制， 从而产生新的、更有效的疗法来预防或减轻PD的DA神经变性作用。

PROJECT SUMMARY In Parkinson’s Disease (PD), dopamine (DA) neurons degenerate in the substantia nigra pars compacta (SNc). In contrast, the DA neurons of the ventral tegmental area (VTA) are relatively protected from PD-induced degeneration, but the cause of this neuroprotection is unknown. One possible answer may derive from the unique properties of VTA DA neurons: a subset of these cells co-release glutamate and express the vesicular glutamate transporter 2 (VGLUT2). DA neurons that express VGLUT2 are more likely to survive neurotoxic insult in animal models of PD, and DA neuron VGLUT2 upregulation is observed in neurons resilient to DA neurotoxins. Significantly, VGLUT2 expression is upregulated in DA neurons across Drosophila, rodents, non-human and human primates in response to cell stressors, suggesting that this an evolutionarily-conserved mechanism that confers protection against DA neuron degeneration. Moreover, in Drosophila, I discovered females express more Drosophila VGLUT (dVGLUT) compared to males. I also found males flies are markedly more vulnerable to DA neuron degeneration and exhibit more motor deficits compared to females in DA neurotoxin models of PD [e.g., paraquat and 6-hydroxydopamine (6OHDA)] analogous to the sex-specific sequelae of human PD. These findings indicate that VGLUT2 expression is likely part of a regulatory mechanism that may protect these cells and that likely impacts sex differences in PD. These data also show the genetically tractable fly model can be utilized as a powerful experimental system to investigate mechanisms of DA neuron resilience and vulnerability in PD. Given VGLUT’s roles in DA neuron resilience, the central goals of this proposal are to identify: 1) how DA neuron VGLUT expression impacts DA neuron vulnerability, 2) whether the sex differences in DA neuron resilience depend on differences in DA neuron VGLUT expression, and 3) how DA neuron VGLUT2 expression changes in human PD. I will test the hypothesis that DA neuron VGLUT expression confers increased protection in DA neurons, especially in females since they express more VGLUT compared to males. The long-term goals of this proposal are to i) determine the role of VGLUT in mediating vulnerability and sex differences in response to 6OHDA and paraquat in the fly model (Aim 1), and ii), measure DA neuron VGLUT2 expression in human PD (Aim 2). To test these goals, I will use RNA-interference to knock down dVGLUT expression in Drosophila DA neurons, and measure DA neuron vulnerability in male versus female flies in 6OHDA and paraquat PD models. In parallel, I will measure DA neuron VGLUT2 expression in human PD using postmortem human midbrain of both male and female PD patients and matched controls. These experiments will establish DA neuron VGLUT expression as a novel mechanism of neuroprotection in PD, leading to new, more effective therapies to prevent or mitigate the DA neurodegenerative effects of PD.