DNA Repair Deficiency Associated with Obesity and the Metabolic Syndrome

与肥胖和代谢综合征相关的 DNA 修复缺陷

• 批准号: 7728334
• 负责人: R. Stephen Lloyd
• 金额: $ 36.57万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-20 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7728334
• 关键词: A Mouse; Adult; Affect; American; Animals; Backcrossings; Base Excision Repairs; Biological; Biological Assay; Body Composition; Cardiovascular Diseases; Cell Extracts; Cell Line; Cell Nucleus; Cell Survival; Cells; Circadian Rhythms; Complement; DNA; DNA Damage; DNA Repair; DNA Repair Disorder; DNA biosynthesis; DNA glycosylase; DNA lesion; Data; Diet; Disease; Disease Progression; Dyslipidemias; Eating; Embryo; Enzymes; Epidemic; Etiology; Evaluation; Exhibits; Experimental Designs; Exposure to; Fat-Restricted Diet; Fatty Liver; Fatty acid glycerol esters; Female; Fibroblasts; Gene Expression; Gene Mutation; Generations; Genes; Genetic Transcription; Genome; Hepatic; Home environment; Homeostasis; Human; Hyperinsulinism; Hypertension; Insulin Resistance; Investigation; Knock-out; Knockout Mice; Lead; Lesion; Lipids; Liver diseases; Lung; Magnetic Resonance Imaging; Malignant Neoplasms; Malignant neoplasm of liver; Measures; Metabolic; Metabolic syndrome; Mitochondria; Mitochondrial DNA; Molecular; Monitor; Morbid Obesity; Movement; Mus; Mutagenesis; Nitric Oxide; Non-Insulin-Dependent Diabetes Mellitus; Nonesterified Fatty Acids; Nuclear; Nucleic Acids; OGG1 gene; Obesity; Organism; Outcome; Oxidative Stress; Phenotype; Physiological; Production; Protein Isoforms; Proteins; Purines; Reactive Oxygen Species; Relative (related person); Role; Running; Shuttle Vectors; Site; Stress; Symptoms; System; Techniques; Testing; Transcript; Transgenic Mice; Variant; Vitamin K 3; Weight; base; carcinogenesis; cellular targeting; comparative; human disease; killings; lipid metabolism; liquid chromatography mass spectrometry; male; middle age; mitochondrial dysfunction; mouse model; oxidant stress; prevent; public health relevance; purine; repaired; response

DESCRIPTION (provided by applicant): Exposure to oxidative stress conditions and the generation of excessive reactive oxygen species (ROS) are generally hypothesized to be a common causative factor in the etiology of several human diseases including, but not limited to, fatty liver disease, dyslipidemia, insulin-resistant type 2 diabetes, cardiovascular disease/hypertension, and obesity (collectively known as Metabolic Syndrome). Although it is well established that lipids, proteins and nucleic acids are critical cellular targets for endogenously and exogenously produced ROS, until recently, deficiencies in repair of ROS-induced DNA base damage had not been considered to be key in the aforementioned diseases, while being considered central to carcinogenesis. However, two knockout mouse models (neil1 and ogg1) have been created in which the initiation of base excision repair of oxidatively-damaged DNA is defective, and in both models, mice develop subsets of symptoms consistent with Metabolic Syndrome. Disease manifestations in the neil1 knockout mice may include obesity, fatty liver disease, dyslipidemia and hyperinsulinemia, with male knockouts much more severely affected than females. In addition, analyses of nuclear DNAs isolated from these mice reveal the accumulation of high levels of ROS-damaged bases and mitochondrial DNAs (mtDNA) show both increased steady-state base damage and large deletions relative to control littermates. Since it known that excessive oxidative stress can induce symptoms of Metabolic Syndrome in repair-proficient organisms, it is hypothesized that the loss of NEIL1 or OGG1 lowers the threshold at which oxidatively stress-induced disease is manifested. In the absence of repair, the progressive accumulation of compromised mtDNA genomes leads to deficiencies in energy production, as well as alterations in free fatty acid and lipid metabolism. In order to test this hypothesis, multiple physiological parameters will be evaluated for changes in neil1-/-, ogg1-/- and neil1-/-ogg1-/- mice and their wild-type littermates during pro-oxidant challenges versus control conditions. These data will be correlated with rates of pathological changes and mitochondrial and nuclear DNA damage accumulation as measured by GC/MS and quantitative PCR. These analyses will be complemented by examining the role of NEIL1 in the modulation of survival, mutagenesis, and mitochondrial function in response to oxidative or nitric oxide stress conditions. Further, since repair of mtDNA is hypothesized to be critical in maintaining metabolic homeostasis, experimental designs are proposed to establish intracellular distribution of various NEIL1 isoforms and determine the biological consequences of expressing nuclear or mitochondrially-targeted forms of these enzymes in neil1-/- cells. PUBLIC HEALTH RELEVANCE: The growing epidemic of human obesity is currently estimated to affect over 60 million adult Americans, with secondary consequences including, but not limited to, fatty liver disease, cardiovascular disease, and insulin resistance/type 2 diabetes, collectively known as the Metabolic Syndrome. A potential underlying molecular mechanism for these diseases is suggested by the study of DNA repair-deficient mouse models that lack oxidative DNA base damage repair and exhibit many of the defining hallmarks of the Metabolic Syndrome: severe obesity, fatty liver disease, dyslipidemia, and insulin resistance. These investigations will examine the role of reduced DNA repair in the onset and progression of these diseases.

描述（由申请人提供）：通常认为暴露于氧化应激状况和过度活性氧（ROS）的产生是几种人类疾病的病因中的常见病因因素，包括但不限于脂肪肝疾病，脂肪疾病，低胰岛素抑制蛋白，胰岛素2型糖尿病型糖尿病，心脏疾病，估计性及其含量均为相结合。尽管众所周知，脂质，蛋白质和核酸是内源性和外源产生的ROS的关键细胞靶标，但直到最近，还没有认为ROS ROS诱导的DNA碱损伤的缺陷尚未被认为是上述疾病的关键，而被认为是癌变的中心。但是，已经创建了两个基因敲除小鼠模型（Neil1和Ogg1），其中氧化受损的DNA的碱基切除修复的启动是有缺陷的，并且在这两个模型中，小鼠都会形成与代谢综合征一致的症状子集。 Neil1基因敲除小鼠中的疾病表现可能包括肥胖，脂肪肝病，血脂异常和高胰岛素血症，男性敲除比女性更严重。此外，对这些小鼠分离的核DNA的分析揭示了高水平的ROS损坏碱基和线粒体DNA（mtDNA）的积累，均显示稳态碱基损伤增加，而且相对于对照同窝仔，且相对于对照同窝的损坏增加了。由于它知道过度氧化应激会诱导促进良好的生物体中代谢综合征的症状，因此假设NEIL1或OGG1的丧失降低了氧化应激诱导的疾病的阈值。在没有修复的情况下，受损的mtDNA基因组的进行性积累会导致能量产生的缺乏，并改变游离脂肪酸和脂质代谢。为了检验这一假设，将评估多个生理参数，以了解Neil1 - / - ，Ogg1 - / - 和Neil1-/ - Ogg1-/ - 小鼠及其野生型同窝仔的变化在促氧化挑战与控制条件下。这些数据将与通过GC/MS和定量PCR测量的病理变化率以及线粒体和核DNA损伤的积累相关。这些分析将通过研究Neil1在响应氧化或一氧化氮应激条件下的生存，诱变和线粒体功能调节中的作用来补充。此外，由于假设MTDNA的修复对于维持代谢稳态至关重要，因此提出了实验设计来建立各种Neil1同工型的细胞内分布，并确定表达Neil1-/ - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - / - 的生物学后果。公共卫生相关性：目前估计人类肥胖的流行病会影响超过6000万的成年美国人，次要后果，包括但不限于脂肪肝病，心血管疾病和胰岛素抵抗/2型糖尿病，统一称为代谢综合征。通过研究缺乏氧化DNA碱基损伤修复的DNA修复缺陷的小鼠模型，建议了这些疾病的潜在潜在分子机制，并表现出代谢综合征的许多定义标志：严重的肥胖，脂肪肝病，血脂异常和胰岛素抵抗。这些研究将检查DNA修复减少在这些疾病的发作和进展中的作用。