Aging of the Nigrostriatal System: Role of DNA Repair

描述(由申请人提供)：本提案的目的是确定年龄相关的DNA累积氧化损伤在决定与衰老相关的神经元丢失中所起的作用。具体地说，这一建议旨在了解内在因素，如DNA修复能力，如何在调节DNA损伤方面发挥重要作用，以及这种相互作用如何在正常衰老过程中对特定神经元群体的稳定性至关重要。这些信息可能有助于收集与衰老相关的神经病理所涉及的机制，例如帕金森氏症。 具体目的1.检测野生型和mOggl基因敲除小鼠衰老过程中黑质纹状体通路的DNA氧化/DNA修复状态和稳定性。 具体目的2.评估黑质纹状体系统抗氧化防御中的年龄依赖效应，并确定mOgg1的缺乏是否改变了抗氧化系统中年龄相关的变化。 具体目的3.研究mOgg1活性缺失是否加剧了MPTP诱导的帕金森病小鼠黑质纹状体DA神经元的丢失。 将使用129/SVJ雄性小鼠，将分析3、12、18和24个月龄小鼠的黑质和尾壳核的DNA氧化损伤、DNA修复能力和黑质-尾壳核电路的完整性，通过尾壳核和黑质酪氨酸羟基酶神经元中的多巴胺水平进行评估。为了确定在衰老过程中，完整的DNA修复是否对维持正常神经元种群至关重要，将在缺乏mOgg1(负责清除oxo8dG的糖基酶)的小鼠身上进行类似的研究。为了确定某些神经元群体在克服升高的氧化应激中的反应，将在每个选定的研究年龄评估内源性抗氧化系统的活性和水平。野生型和基因敲除小鼠将被神经毒素MPTP攻击，以检测由于衰老和缺乏DNA修复而导致的多巴胺能神经元敏感性的变化

DESCRIPTION (provided by applicant): The objective of this proposal is to define the role that age-dependent accumulation oxidative damage to DNA has in dictating the neuronal loss associated with aging. Specifically, this proposal aims to understand how an intrinsic factor, such as DNA repair capacity, has a major role in regulating DNA damage and how this interplay is crucial for the stability of specific neuronal populations during the normal process of aging. This information could be useful in gleaning on the mechanisms involved in neuropathologies associated with aging, such as Parkinson's disease. Specific Aim 1. To determine the status of DNA oxidation/DNA repair and stability of the nigrostriatal pathway of wild-type and mOggl knockout mice during aging. Specific Aim 2. To evaluate age-dependent effects in the antioxidant defenses of the nigrostriatal system and determine whether the lack of mOggl alters age-dependent changes in antioxidant systems. Specific Aim 3. To investigate whether lack of mOggl activity potentiates the loss of nigrostriatal DA neurons in murine MPTP-induced Parkinsonism. 129/SVJ male mice will used, the substantia nigra and caudate putamen of mice at ages 3, 12, 18, and 24 months will be analyzed for oxidative damage to DNA, DNA repair capacity, and integrity of the nigral-caudate putamen circuitry, as assessed by dopamine levels in caudate putamen and tyrosine hydroxylase neurons in substantia nigra. To determine, whether intact DNA repair is essential in maintaining normal neuronal populations during aging, similar studies will be carried out in mice lacking mOggl (glycosylase responsible for removal of oxo8dG). To identify the response that certain neuronal populations have in overcoming elevated oxidative stress, activities and levels of endogenous antioxidant system will be assessed at each age selected for the study. Wild type and knockout mice will be challenged with the neurotoxin MPTP in order to detect changes in the dopaminergic neurons susceptibility as a consequence of aging and lack of DNA repair