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，零星疾病的易感性和发病率中的直接作用尚不清楚，除非与癌症易感性和早熟相关的可遗传疾病群体，例如静脉色素色素，遗传性非polypolypolypoismosim，遗传性非polypolypiss Colientalcis Colientalal Carcinoma（HNPCC），以及其他疾病？个体的DNA修复能力（DRC）可能是识别偶发发生疾病风险的个体的有用临床工具。彗星测定法的临床应用各不等，从化学疗法剂的生殖器和细胞毒性的评估到精子中氧化性DNA损伤水平与男性不育症的相关性。在人群研究中，使用碱性彗星测定法评估DNA修复能力（DRC）受到控制的困难，无法控制实验性变异性，制定适当的内部标准和建立适合在该测定法中使用的冷冻保存淋巴细胞的方法。这项工作的目的是开发一种准确，可再现和有效的彗星测定方法，用于评估冷冻保存淋巴细胞中的DNA修复。迄今为止，我们的工作表明，未刺激的人冷冻淋巴细胞可用于使用彗星测定法准确测量DRC。这些改进已用于评估整个生命周期多样性（Handls）研究中健康衰老的个体临床人群中的DRC。 整个生命周期（Handls）研究（Handls）多样性社区的健康衰老是一项基于社区的，流行病学上驱动的多学科研究工作，旨在专注于评估巴尔的摩社会经济多样性的高加索人和非裔美国人的健康差异。 Handls研究的一个领域研究了氧化应激和缺陷在DNA修复中的可能作用在与年龄相关疾病的发展中。非洲裔美国人和低SES个人与年龄相关疾病的早期出现和严重程度增加，这表明导致健康差异出现的因素也可能引起？过早衰老的表型？还是加速衰老？虽然我们不认为健康差异是由于与已知可遗传的后代综合征相关的基因的遗传改变而产生的。我们确实假设，在早期发作年龄相关疾病率高的低SES人群中，生物学，心理社会，社会经济和环境因素的相互作用可能导致一种在生物学上与这些综合症相似的加速衰老表观型，类似于这些综合征与氧化应激者对氧化应激的敏感性增加，氧化DNA损伤的过早降低了DNA，DNA损伤，DNA损伤的过早积累。因此，健康差异可能是这种复杂相互作用在高风险中的最终产物。 我们正在研究由四个年龄匹配的男性和女性高加索人和非洲裔美国人在30-64岁之间的淋巴细胞中造成的DNA损伤的修复。使用文献中描述的参数（包括DNA修复的半个时间和30分​​钟后残留的DNA损伤）评估DRC。但是，我们的初步发现包括我们称之为新的维修参数的定义？DNA修复的初始速率。我们的数据表明？ DNA修复的初始速度？是否可以近似DNA修复的快速组成部分，并且残留的DNA损伤？测量可能对应于基础科学DNA修复文献中讨论的慢DNA修复成分。这些参数的临床意义需要进一步研究。