Oxidative DNA Damage And Its Processing

DNA氧化损伤及其处理

• 批准号: 8736600
• 负责人: Vilhelm A Bohr
• 金额: $ 19.72万
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8736600
• 关键词: Acute; Age; Aging; Aging-Related Process; Alzheimer' s Disease; Animals; Base Excision Repairs; Cells; Cellular Stress; DNA; DNA Damage; DNA Double Strand Break; DNA Modification Process; DNA Repair; DNA Single Strand Break; DNA lesion; DNA strand break; DNA-Directed DNA Polymerase; Development; Double Strand Break Repair; Environmental Risk Factor; Functional disorder; Genetic; Genomic Instability; Goals; Human; Individual; Infarction; Ischemic Stroke; Lead; Lesion; Life; Lipids; Maintenance; Malignant Neoplasms; Measures; Metabolic; Metabolism; Mitochondrial DNA; Mitotic; Modification; Molecular; Mutagenesis; Mutate; Nerve Degeneration; Neurodegenerative Disorders; Neurologic Dysfunctions; Nuclear; Organism; Oxidative Stress; Pathway interactions; Peripheral Blood Mononuclear Cell; Play; Polymerase; Population Study; Premature aging syndrome; Process; Proliferating; Proteins; Relative (related person); Role; Sampling; Sex Characteristics; Signal Transduction; Single Strand Break Repair; Site; Twin Multiple Birth; Twin Studies; aged; aging brain; base; brain cell; environmental agent; insight; interest; nervous system disorder; neurogenesis; normal aging; oxidative DNA damage; oxidative damage; population based; protein protein interaction; relating to nervous system; repair enzyme; repaired; research study; response

Oxidative lesions are removed from DNA primarily via the base excision repair (BER) pathway. BER is carried out through four enzymatic steps, but it is now clear that several other proteins modulate BER efficiency through protein-protein interactions. We and others identified several protein interactions for the core BER enzymes. Oxidative DNA damage is implicated in brain aging, neurodegeneration and neurological diseases. Damage can be created by normal cellular metabolism, which accumulates with age, or by acute cellular stress conditions which create bursts of oxidative damage. Brain cells have a particularly high basal level of metabolic activity and use distinct oxidative damage repair mechanisms to remove oxidative damage from DNA and dNTP pools. Accumulation of this damage in the background of a functional DNA repair response is associated with normal aging, but defective repair in brain cells can contribute to neurological dysfunction. The requirement for BER in proliferating cells also correlates with high levels of many of the BER enzymes in neurogenesis after DNA damage. However, the pathway is also necessary for normal neural maintenance as larger infarct volumes after ischemic stroke are seen in some glycosylase deficient animals. Further, the requirement for DNA polymerase in post-mitotic BER is potentially more important than in proliferating cells due to reduced levels of replicative polymerases. The BER response may have particular relevance for the onset and progression of many neurodegenerative diseases associated with an increase in oxidative stress including Alzheimer's, which we are pursuing. Genetic and environmental factors likely influence DNA repair capacity. In order to gain more insight into the genetic and environmental contribution to the molecular basis of DNA repair, we have performed a human twin study, where we focused on the consequences of some of the most abundant types of DNA damage (single-strand breaks), and some of the most hazardous lesions (DNA double-strand breaks). DNA damage signaling response (Gamma-H2AX signaling), relative amount of endogenous damage, and DNA-strand break repair capacities were studied in peripheral blood mononuclear cells from 198 twins (94 monozygotic and 104 dizygotic). We did not detect genetic effects on the DNA-strand break variables in our study. In another study, we focused on potential age-associated changes in DNA damage response and the capacities of repairing DNA single-strand breaks (SSBs) and double-strand breaks (DSBs) in human peripheral blood mononuclear cells (PBMCs). Of these lesions, DSBs are the least frequent but the most dangerous for cells. We have measured the level of endogenous SSBs, SSB repair capacity, -H2AX response, and DSB repair capacity in a study population consisting of 216 individuals from a population-based sample of twins aged 40-77 years. Age in this range did not seem to have any effect on the SSB parameters. However, -H2AX response and DSB repair capacity decreased with increasing age, although the associations did not reach statistical significance after adjustment for batch effect across multiple experiments. No gender differences were observed for any of the parameters analyzed. Our findings suggest that in PBMCs, the repair of SSBs is maintained until old age, whereas the response to and the repair of DSBs decreases.

氧化损伤主要通过碱基切除修复(BER)途径从DNA中移除。BER是通过四个酶步骤进行的，但现在很清楚，其他几种蛋白质通过蛋白质-蛋白质相互作用来调节BER效率。我们和其他人确定了核心BER酶的几种蛋白质相互作用。氧化DNA损伤与大脑老化、神经退行性疾病和神经系统疾病有关。损伤可能是由正常的细胞代谢造成的，这种代谢随着年龄的增长而积累，或者是由急性细胞应激条件造成的突发性氧化损伤。脑细胞具有特别高的基础代谢活动水平，并使用不同的氧化损伤修复机制来消除DNA和dNTP池中的氧化损伤。在功能性DNA修复反应的背景下，这种损伤的积累与正常衰老有关，但脑细胞修复缺陷可能导致神经功能障碍。增殖细胞对BER的需求也与DNA损伤后神经发生中许多BER酶的高水平相关。然而，该途径对于正常的神经维持也是必要的，因为在一些糖基酶缺陷的动物中可以看到缺血性中风后更大的梗塞体积。此外，由于复制聚合酶水平降低，有丝分裂后BER对DNA聚合酶的需求可能比增殖细胞更重要。BER反应可能与许多与氧化应激增加相关的神经退行性疾病的发生和发展特别相关，包括我们正在研究的阿尔茨海默氏症。 遗传和环境因素可能会影响DNA修复能力。为了更深入地了解遗传和环境对DNA修复分子基础的贡献，我们进行了一项人类双胞胎研究，重点研究了一些最丰富的DNA损伤类型(单链断裂)和一些最危险的损伤(DNA双链断裂)的后果。对198例双生子(94例同卵，104例异卵)外周血单个核细胞DNA损伤信号反应(Gamma-H2AX信号)、内源性损伤相对量和DNA链断裂修复能力进行了研究。在我们的研究中，我们没有检测到基因对DNA链断裂变量的影响。在另一项研究中，我们专注于DNA损伤反应的潜在年龄相关变化以及修复人外周血单个核细胞(PBMCs)DNA单链断裂(SSB)和双链断裂(DSB)的能力。在这些损害中，DSB是最不常见的，但对细胞来说最危险。我们在一个由216个个体组成的研究群体中测量了内源性SSB水平、SSB修复能力、-H_2AX反应和DSB修复能力，这些个体来自40-77岁的双胞胎样本。在此范围内的年龄似乎对SSB参数没有任何影响。然而，-H_2AX反应和DSB修复能力随着年龄的增长而下降，尽管在对多个实验的批处理效应进行调整后，这些关联没有达到统计学意义。在所分析的任何参数中都没有观察到性别差异。我们的发现表明，在PBMCs中，SSB的修复一直维持到老年，而对DSB的反应和修复减少。