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和沃纳？S综合征等。个体的DNA修复能力(DRC)可能是一种有用的临床工具，可用于识别有偶发性疾病风险的个体。彗星试验的临床应用多种多样，从评估化疗药物的基因和细胞毒性到精子中氧化DNA损伤水平与男性不育的关系。在人类群体研究中使用碱性彗星试验来评估DNA修复能力(DRC)一直受到以下困难的限制：难以控制试验间的变异性，难以制定适当的内部标准，以及建立适用于该分析的冷冻保存淋巴细胞的方法学。这项工作的目的是建立一种准确、可重复性和高效的彗星试验方法来评估冷冻保存的淋巴细胞的DNA修复。到目前为止，我们的工作表明，未经刺激的人冷冻保存的淋巴细胞可以使用彗星实验准确地测量DRC。这些改进已被用于评估在社区多样性健康老龄化(HANDLS)研究中的临床队列个人的DRC。 跨寿命多样性社区健康老龄化(HANDLS)研究(HANDLS)是一项以社区为基础、流行病学驱动的多学科研究成果，旨在评估巴尔的摩社会经济多元化的高加索人和非裔美国人的健康差距。HANDLS研究的一个领域是考察氧化应激和DNA修复缺陷在年龄相关疾病发展中的可能作用。在非裔美国人和低SES人群中，年龄相关疾病的早期出现和严重程度的增加表明，导致健康差距出现的因素也可能导致一种表型？过早衰老？或者？加速衰老？虽然我们并不认为健康差距是由已知的可遗传的孕激素综合征相关基因的基因变化造成的。我们确实假设，在早发性年龄相关疾病发生率较高的低SES人群中，生物、心理社会、社会经济和环境因素的相互作用可能导致生物上类似于这些综合征的加速衰老的表型，这些综合征对氧化应激增加易感性，氧化DNA损伤过早积累，DNA修复缺陷和氧化应激生物标记物水平较高。因此，健康差距可能是高危人群这种复杂互动的最终结果。 我们正在检测四组年龄匹配的男性和女性高加索人以及30-之间的非裔美国人的淋巴细胞对γ-射线造成的DNA损伤的修复。DRC正在使用文献中描述的参数进行评估，包括DNA修复的一半时间和30分钟后残留的DNA损伤。然而，我们的初步发现包括定义了一个新的修复参数，我们称之为DNA修复的初始速率。我们的数据表明？DNA修复的初始速度是多少？可以近似DNA修复的快速成分，以及残留的DNA损伤？测量可能对应于基础科学DNA修复文献中讨论的缓慢DNA修复成分。这些参数的临床意义需要进一步研究。