Fetal DNA oxidation and repair in neurodegeneration

神经退行性疾病中胎儿 DNA 氧化和修复

• 批准号: 7038483
• 负责人: PETER G WELLS
• 金额: $ 16.2万
• 依托单位: UNIVERSITY OF TORONTO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7038483
• 关键词: DNA damage; DNA repair; N glycosidase; behavior test; catalase; developmental neurobiology; diet therapy; dietary proteins; embryo /fetus toxicology; food contamination; free radical oxygen; genetic regulatory element; genetic susceptibility; genetic transcription; genetically modified animals; guanine analog; high performance liquid chromatography; laboratory mouse; methylmercury; microarray technology; mother /embryo /fetus nutrition; neural degeneration; neurotoxicology; neurotoxins; nutrition related tag; oxidative stress

DESCRIPTION (provided by applicant): Methylmercury (MeHg) is an environmental agent introduced to humans primarily via the ingestion of contaminated seafood. Prenatal MeHg exposure induces neurodevelopmental deficits, at doses below those causing systemic toxicity. One potential toxicological mechanism for this and other environmental chemicals likely involves reactive oxygen species (ROS) formation, as the fetus has low antioxidative protection. This toxicity may involve oxidative DNA lesions, the most prominent of which is 8-oxoguanine (8-oxoG), which can result in mutations or altered gene transcription. The latter is potentially relevant to developmental pathologies. Repair of 8-oxoG is carried out by the base excision (BER) and transcription-coupled (TCR) repair pathways. We hypothesize that ROS-mediated oxidative DNA damage in fetal brain modifies specific gene expression levels, contributing to postnatal neurodevelopmental deficits. The progeny of mouse models with genetic alterations in 8-oxoG repair activity will be assessed for neurodevelopmental deficits after in utero exposure to MeHg. Oxoguanine glycosylase 1 (ogg1) knockout (BER-deficient) and Cockayne syndrome B (CSB) knockout (TCR-deficient) mice will be tested as repair-deficient models, while transgenic mice expressing highly active bacterial formamidopyrimidine glycosylase (Fpg) will be genetically engineered and employed as a BER-enhanced model. Fetal ROS and 8-oxoG, specific gene regulatory targets for oxidation and associated gene expression changes in utero will be analyzed in the same fetal brains, and assessed with respect to postnatal CMS pathologies in the progeny. 8-OxoG will be quantified by HPLC with electrochemical detection, oxidation of target gene regulatory elements will be characterized by ligand- mediated PCR, gene expression by microarray analysis, and neurodevelopmental deficits by behavioral tests. These studies will provide mechanistic insight into the fetal origin of environmentally-induced neurodevelopmental defects, and the role of DNA repair activity as a risk factor.

描述（由申请人提供）：甲基汞（MEHG）是一种环境药物，主要是通过摄入受污染的海鲜引入的人类。产前MEHG暴露会诱发神经发育缺陷，低于引起全身毒性的剂量。对于这种和其他环境化学物质的一种潜在毒理学机制可能涉及活性氧（ROS）形成，因为胎儿具有低抗氧化保护。这种毒性可能涉及氧化性DNA病变，其中最突出的是8-氧气（8-oxog），这可能导致突变或改变基因转录。后者可能与发育病理学有关。 8-oxog的修复是通过基础切除（BER）和转录耦合（TCR）修复途径进行的。我们假设ROS介导的胎儿脑中的氧化DNA损伤会改变特定的基因表达水平，从而导致产后神经发育缺陷。在子宫内暴露于MEHG后，将评估具有8-oxog修复活性遗传改变的小鼠模型的后代。氧氨基糖基化酶1（OGG1）基因敲除（缺乏BER）和Cockayne综合征B（CSB）敲除（缺乏TCR）小鼠将作为维修缺陷模型进行测试，而表达高度活跃的细菌甲酰胺酰胺酰胺类糖基酶（FPG）的转基因小鼠（FPG）将属于Genetery-Geneterynered and Genetricalionered inthereed。将在同一胎儿大脑中分析胎儿ROS和8-oxog，用于氧化和相关基因表达变化的特定基因调节靶标，并根据后代的产后CMS病理进行评估。 8-OXOG将通过HPLC通过电化学检测来量化，靶基因调节元件的氧化将以配体介导的PCR，通过微阵列分析的基因表达以及通过行为测试来表征神经发育缺陷。这些研究将提供有关环境引起的神经发育缺陷的胎儿起源以及DNA修复活性作为危险因素的作用的机械洞察力。