DNA MODIFICATIONS--I COMPOUNDS AS BIOMARKERS OF AGING

我们将应用~(32)P标记技术来研究年龄- 依赖的DNA修饰，称为I-化合物，是潜在的 衰老的生物标志物。I-化合物是最近发现的DNA 在我们实验室中发现的类似加成物的DNA衍生物 在啮齿动物组织中随年龄增长而增加。I-化合物配置文件是 强烈依赖于组织、物种和(在较小程度上)性别 关于动物的。它们似乎显示出很小的动物间差异， 在相同年龄的动物中，无论是定性的还是定量的。 因此，I-化合物可能为衰老提供一个定量的生物标志物 如果进行测量，这将有助于对人类的生物监测 在容易接近的细胞或组织中。我们将检验这一假设 利用NIA/NCTR生物标记物研究群体的大鼠，重点 白血球和皮肤的DNA，即可从 人类具有最低程度的侵袭性。 将从个体身上分离出白细胞和皮肤DNA 男女费舍尔344(F344)、布朗-挪威(BN)和F344 不同日龄的X-BN杂交大鼠，分别从自由采食和 饮食限制组。将有8个年龄点：4，6，8，10， 12、16、20、24个月，每点6只大鼠。此外，肝脏 肾脏DNA将从混合的组织样本中分离出来 Biomarker研究在每个年龄点聚集大鼠。级别 而I-化合物的模式将通过32P- 共价DNA修饰的后标记试验。总计 1536个DNA样本将在5年的时间里进行检查 这个项目。Will大鼠肝、肾DNA分析 显示I-化合物在内脏的变化是否平行 那些在白血球和皮肤中的。在每个年龄段，都有足够的 将在#年进行一些分析来评估这一方法。 关于它的重复性、敏感性、重要性的术语 变化、非致命性(例如，使用白细胞)、潜力 与人类老龄化的相关性，以及技术要求。这 研究将为这个问题提供一个明确的答案 I-化合物的测量是否会提供一个有用的 非侵入性的衰老生物监测方法。

We will apply a 32P-labeling technique to investigate age- dependent DNA modifications, termed I-compounds, as potential biomarkers of aging. I-compounds are recently discovered DNA adduct-like DNA derivatives that were found in our laboratory to increase with age in rodent tissues. I-compound profiles are strongly dependent on tissue, species, and (to a lesser extent) sex of animals. They appear to show little inter-animal variation, both qualitatively and quantitatively, in animals of the same age. I-compounds may thus provide a quantitative biomarker of aging that would be useful in the biomonitoring of humans if measured in easily accessible cells or tissues. We will test this hypothesis using rats of the NIA/NCTR biomarker research colony, focusing on DNA of white blood cells and skin, i.e. tissues available from humans with a minimum degree of invasiveness. White blood cell and skin DNA will be isolated from individual female and male Fischer 344 (F344), Brown-Norway (BN), and F344 x BN hybrid rats of different ages, from both ad libitum fed and dietary restricted groups. There will be 8 age points: 4, 6, 8, 10, 12, 16, 20, and 24 months and 6 rats per point. In addition, liver and kidney DNA will be isolated from pooled tissue samples of the biomarker research colony rats at each of the age points. Levels and patterns of I-compounds will be analyzed by a 32P- postlabeling assay for covalent DNA modifications. A total of 1536 DNA specimens will be examined over the 5-year course of the project. Analysis of liver and kidney DNA of the rats will show whether I-compound changes in internal organs parallel those in white blood cells and skin. At each age, a sufficient number of analyses will be conducted to assess this approach in terms of its reproducibility, sensitivity, significance of rate of change, non-lethality (e.g., use of white blood cells), potential relevance to human aging, and technical requirements. This research will provide a definitive answer to the question as to whether the measurement of I-compounds will provide a useful non-invasive method for biomonitoring of aging.