DNA Damage and Repair in Parkinsons Disease

描述（由申请人提供）： 由于神经元的高代谢活性和低水平的抗氧化防御，它们可能特别容易受到活性氧的DNA损伤[1]。因此，氧化DNA损伤的修复对于正常的脑功能至关重要。关于神经元DNA修复知之甚少，因此它是一个重要的研究领域。通过氧化应激与DNA损伤的病因学联系已涉及帕金森病（PD）的发病机制[2，3]。PD是一种进行性神经退行性疾病，其病理特征主要是黑质多巴胺能神经元的损失。触发PD神经变性的最初潜在机制尚不清楚。在PD患者的黑质多巴胺能神经元中检测到DNA损伤水平升高[4-6]。目前还不清楚DNA损伤是否是神经元丢失的原因，或者是存活神经元中疾病的附带现象。还发现PD患者黑质多巴胺能神经元中“GO”酶（OGG 1、MUTY和MTH 1）（参与氧化DNA损伤修复的蛋白质）的表达增加[7- 9]。然而，目前尚不清楚GO系统在神经元的核和线粒体基因组中防止DNA损伤和/或突变的程度。拟议的实验将测试的假设，即DNA损伤是在黑质多巴胺能细胞损失的早期事件和GO途径是重要的，防止这种氧化性DNA损伤。如果DNA损伤可能是神经元变性的潜在机制，并且GO修复在预防这种损伤方面很重要，那么这些代表了开发治疗以减缓PD进展的新靶点。将使用PD和人类死后脑组织的鱼藤酮模型的分子、生物化学和细胞技术的组合。该提议有以下两个具体目标：（1）确定DNA损伤在多巴胺能神经元进行性丧失中的时间和空间作用;（2）确定GO成员（OGG 1，MutY，Mth 1）在PD体外和体内模型中修复鱼藤酮诱导的DNA损伤中的作用。

DESCRIPTION (provided by applicant): Neurons may be particularly prone to DNA damage by reactive oxygen species due to their high metabolic activity and low levels of antioxidant defenses [1]. Repair of oxidative DNA damage is therefore essential for normal brain function. Very little is known about neuronal DNA repair and therefore it is an important field for investigation. An etiological link to DNA damage via oxidative stress has been implicated in the pathogenesis of Parkinson's disease (PD) [2, 3]. PD is a progressive neurodegenerative disorder that is pathologically characterized largely by the loss of dopaminergic neurons of the substantia nigra. The initial underlying mechanism(s) that triggers neurodegeneration in PD is unknown. Elevated levels of DNA damage were detected in the dopaminergic neurons of the substantia nigra in PD patients [4-6]. It is unclear whether DNA damage is responsible for neuronal loss or is an epiphenomenon of the disease in the surviving neurons. Expression of "GO" enzymes (OGG1, MUTY, and MTH1), proteins involved in the repair of oxidative DNA damage, were also found to be increased in the dopaminergic neurons in the substantia nigra of PD patients [7- 9]. However, the extent to which the GO system acts to prevent DNA damage and/or mutations in both the nuclear and mitochondrial genomes in neurons is presently unclear. The proposed experiments will test the hypothesis that DNA damage is an early event in dopaminergic cell loss in the substantia nigra and that the GO pathway is important in protecting against such oxidative DNA damage. If DNA damage is potentially an underlying mechanism of neuronal degeneration, and GO repair is important in preventing this damage, these represent novel targets for the development of treatments to slow the progression of PD. A combination of molecular, biochemical and cellular techniques using rotenone models of PD and human postmortem brain tissues will be utilized. This proposal has the following two specific aims: (1) Determine the temporal and spatial role of DNA damage in the progressive loss of dopaminergic neurons; and (2) Determine the role of the GO members (OGG1, MutY, Mth1) in the repair of rotenone-induced DNA damage in both in vitro and in vivo models of PD.