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，神经元可能特别容易受到活性氧物种的DNA损伤[1]。因此，氧化DNA损伤的修复对于正常的大脑功能是必不可少的。由于对神经元DNA修复知之甚少，因此它是一个重要的研究领域。通过氧化应激导致DNA损伤的病因学联系被认为与帕金森氏病(PD)的发病机制有关[2，3]。帕金森病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丢失。引发帕金森病神经变性的最初潜在机制(S)尚不清楚。帕金森病患者黑质多巴胺能神经元DNA损伤水平升高[4-6]。目前尚不清楚DNA损伤是否导致神经元丢失，或者是存活神经元中的一种附带现象。参与DNA氧化损伤修复的GO酶(OGG1、MUTY和MTH1)的表达也被发现在PD患者黑质中的多巴胺能神经元中增加[7-9]。然而，GO系统在多大程度上防止神经元核和线粒体基因组中的DNA损伤和/或突变目前尚不清楚。拟议的实验将检验这样一种假设，即DNA损伤是黑质多巴胺能细胞丢失的早期事件，GO途径在保护这种氧化DNA损伤方面起着重要作用。如果DNA损伤可能是神经元变性的潜在机制，而GO修复在防止这种损伤中是重要的，那么这些就是开发减缓PD进展的治疗方法的新靶点。使用鱼藤酮模型的PD和人类死后脑组织的分子、生化和细胞技术的组合将被利用。这项研究有两个具体目的：(1)确定DNA损伤在多巴胺能神经元进行性丢失中的时空作用；(2)在体外和体内PD模型中，确定GO成员(OGG1、MutY、MTH1)在修复鱼藤酮诱导的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.