Measuring DNA Damage and Repair Capacity in Human Popula

测量人类 DNA 损伤和修复能力

• 批准号: 7327074
• 负责人: michele k evans
• 金额: --
• 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/7327074
• 关键词: Measuring; DNA; Damage; Repair; Capacity

The direct role of DNA repair in cellular senescence, aging, sporadic disease susceptibility and incidence remains unclear except in the well know groups of heritable disorders associated with cancer susceptibility and premature aging such as Xeroderma Pigmentosum, Hereditary Non-polyposis Colorectal Carcinoma (HNPCC), and Werner?s syndrome among others. DNA repair capacity (DRC) of individuals may be a useful clinical tool in identifying individuals at risk for sporadically occurring disease. The clinical applications of the COMET Assay are varied ranging from assessment of chemotherapy agent geno- and cytotoxicity to correlation of oxidative DNA damage levels in spermatozoa with male infertility. Use of the Alkaline Comet Assay to assess DNA repair capacity (DRC) in human population studies has been limited by difficulties in controlling for inter-experimental variability, developing appropriate internal standards and establishing a methodology for cryopreserved lymphocytes appropriate for use in this assay. The aim of this work is to develop an accurate, reproducible and efficient comet assay methodology for evaluating DNA repair in cryopreserved lymphocytes. Our work thus far shows that unstimulated human cryopreserved lymphocytes can be used to accurately measure DRC using the comet assay. These refinements have been used to assess DRC in a clinical cohort of individuals in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study. Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study (HANDLS) is a community-based, epidemiologically driven multidisciplinary research effort designed to focus on evaluating health disparities in socioeconomically diverse Caucasians and African Americans in Baltimore. One of the domains of the HANDLS study examines the possible role of oxidative stress and defects in DNA repair in the development of age associated disease. The early appearance and increased severity of age-associated disease among African Americans and low SES individuals suggests that the factors contributing to the emergence of health disparities may also induce a phenotype of ?premature aging? or ?accelerated aging?. While we do not posit that health disparities result from genetic alterations in genes associated with the known heritable progeroid syndromes. We do hypothesize that in low SES populations with high rates of early onset age-associated disease the interaction of biologic, psychosocial, socioeconomic and environmental factors may result in a phenotype of accelerated aging biologically similar to these syndromes with increased susceptibility to oxidative stress, premature accumulation of oxidative DNA damage, defects in DNA repair and higher levels of biomarkers of oxidative stress. Health disparities therefore, may be the end product of this complex interaction in populations at high risk. We are examining the repair of DNA damage induced by ?-irradiation in lymphocytes from four age-matched groups of male and female Caucasians and African Americans between ages 30-64. DRC is being assessed using parameters described in the literature including half time of DNA repair and residual DNA damage after 30 min. Our preliminary findings however include the definition of a new repair parameter that we call ?initial rate of DNA repair. Our data suggest that the? initial rate of DNA repair? may approximate the fast component of DNA repair and that the ?residual DNA damage? measure may correspond to the slow DNA repair component discussed in the basic science DNA repair literature. The clinical implications of these parameters require further investigation.

DNA修复在细胞衰老、衰老、散发性疾病易感性和发病率中的直接作用尚不清楚，除了众所周知的与癌症易感性和过早衰老相关的遗传性疾病组，如着色性干皮病、遗传性非息肉病性结直肠癌（HNPCC）和Werner？S综合征等。DNA修复能力（DRC）的个人可能是一个有用的临床工具，在确定个人的风险，零星发生的疾病。COMET测定的临床应用范围从化疗剂基因和细胞毒性的评估到精子中氧化DNA损伤水平与男性不育的相关性。在人群研究中使用碱性彗星试验评估DNA修复能力（DRC）受到以下困难的限制：控制实验间变异性、开发适当的内标物以及建立适用于该试验的冻存淋巴细胞方法。本工作的目的是开发一种准确，可重复性和有效的彗星试验方法，用于评估冷冻保存的淋巴细胞中的DNA修复。我们的工作迄今为止表明，未刺激的人冷冻保存的淋巴细胞可用于准确地测量DRC使用彗星试验。这些改进已被用于评估DRC在一个临床队列的个人在健康老龄化社区的多样性跨越寿命（HANDLS）研究。 健康老龄化在社区的多样性在整个生命周期（HANDLS）的研究（HANDLS）是一个以社区为基础的，流行病学驱动的多学科研究工作，旨在重点评估健康的差异在社会经济上不同的高加索人和非洲裔美国人在巴尔的摩。HANDLS研究的一个领域是研究氧化应激和DNA修复缺陷在年龄相关疾病发展中的可能作用。早期的外观和增加的严重程度与年龄相关的疾病在非洲裔美国人和低社会经济地位的个人表明，因素有助于出现的健康差距也可能会诱导表型？过早衰老还是？加速老化？虽然我们并不认为健康差异是由已知的遗传性早衰综合征相关基因的遗传改变引起的。我们假设，在低SES人群中，早发性年龄相关疾病的发病率较高，生物学、社会心理学、社会经济学和环境因素的相互作用可能导致加速衰老的表型，生物学上类似于这些综合征，对氧化应激的易感性增加，氧化DNA损伤的过早积累，DNA修复缺陷和氧化应激生物标志物水平较高。因此，健康差距可能是高风险人群中这种复杂相互作用的最终产物。 我们正在研究DNA损伤的修复？-来自年龄在30-64岁之间的男性和女性高加索人和非洲裔美国人的四个年龄匹配组的淋巴细胞中的辐射。刚果民主共和国正在评估使用文献中描述的参数，包括半时间的DNA修复和残留的DNA损伤后30分钟。我们的初步研究结果，但包括一个新的修复参数，我们称之为定义？DNA修复的初始速率。我们的数据表明，？DNA修复的初始速率可能近似于DNA修复的快速成分，而？残留的DNA损伤这一措施可能对应于基础科学DNA修复文献中讨论的缓慢DNA修复组分。这些参数的临床意义需要进一步研究。