Role of NADPH oxidase 1-derived ROS in the pathogenesis of Parkinson's disease

摘要 线粒体功能障碍、氧化应激、蛋白酶体功能受损和蛋白质聚集 是黑质多巴胺能神经元丢失的共同分子基础 属（SNpC）。多巴胺能神经元的线粒体功能障碍和易损性增加 氧化应激与PD的发病机制有密切关系。反应性的分子来源 然而，PD中的氧物质（ROS）尚未清楚阐明。ROS是一种生理副产物 包括线粒体、过氧化物酶体、细胞色素P-450， 黄嘌呤氧化酶、环氧合酶和NO合酶。 NADPH氧化酶（NOX）家族是第一个被发现的酶复合物， 产生超氧化物。在中枢神经系统中已明确确定了Nox同系物 (CNS)并显示在发育、记忆、神经信号传导和心血管疾病中发挥重要作用。 体内平衡与此同时，一个同样重要的证据表明， 异常Nox激活的ROS也可能导致神经退行性变。此外，最近的研究 表明线粒体在NADPH氧化酶介导（尤其是NOX 1）超氧化物中起作用 一代线粒体和NOX 1之间的相互作用放大了ROS的产生， 死亡这表明，两个主要因素，线粒体功能障碍和氧化应激，涉及 在PD发病机制中可能通过NOX系统相互联系。 我们的初步结果表明，DA细胞配备了一氧化氮介导的超氧化物 发电系统NOX 1受氧化应激如6-OHDA和线粒体毒素诱导， 鱼藤酮Rac 1是Nox激活或Nox 1敲低的关键组分，Rac 1的抑制导致了对Nox的保护。 来自6-OHDA给药的黑质DA神经元。LRRK 2突变（G2019 S）增加ROS 在N27 DA细胞中产生的ROS和apocynin，一种特异性的NADPH氧化酶抑制剂减少ROS的产生 由LRRK 2突变体引起。这些拟议的研究将调查1）抑制NOX 1是否会导致 DA神经保护，2）DA细胞特异性转录调控的分子机制， NOX 1和线粒体参与和3）LRRK 2突变是否影响NOX 1和线粒体参与的激活。 介导的ROS产生和随后的DA神经变性。

ABSTRACT Mitochondrial dysfunction, oxidative stress, impairment of proteasomal function and protein aggregation are the common molecular basis of the loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpC). Mitochondrial dysfunction and increased vulnerability of dopaminergic (DA) neurons to oxidative stress has specifically implicated in the pathogenesis of PD. Molecular sources for reactive oxygen species (ROS) in PD however have not been clearly elucidated. ROS are physiologic byproduct of several organelles and biological reactions including mitochondria, peroxisomes, cytochrome P-450, xanthine oxidase, cyclooxygenase and NO synthase. A family of NADPH oxidase (NOX) is the first enzyme complex discovered which is specialized to generate superoxide. Nox homologues have been specifically identified in the central nervous system (CNS) and shown to play major roles in development, memory, neuronal signaling, and cardiovascular homeostasis. At the same time, an equally significant body of evidence has shown that overproduction of ROS by abnormal Nox activation may also contribute to neurodegeneration. Moreover, recent studies indicate that mitochondria play a role in NADPH oxidase-mediated (especially NOX1) superoxide generation. The interplay between mitochondria and NOX1 amplifies ROS generation and results in cell death. This suggests that two cardinal factors, mitochondrial dysfunction and oxidative stress, implicated in the PD pathogenesis may link each other through the NOX system. Our preliminary results demonstrate that DA cells are equipped with the NOX-mediated superoxide generation system. NOX1 was induced by oxidative stress such as 6-OHDA and mitochondrial toxin, rotenone. Inhibition of Rac1, a key component for Nox activation or Nox1 knockdown led to protection of substantia nigra DA neurons from 6-OHDA administration. LRRK2 mutation (G2019S) increased ROS generation in N27 DA cells and apocynin, a specific NADPH oxidase inhibitor reduced ROS production elicited by LRRK2 mutant. These proposed studies will investigate 1) whether inhibition of NOX1 leads to DA neuroprotection, 2) the molecular mechanism underlying DA cell-specific transcriptional regulation of NOX1 and mitochondrial involvement and 3) whether LRRK2 mutations affect the activation of NOX- mediated ROS production and consequential DA neurodegeneration.