Characterizing Life-Span Sociobehavioral Determinants of DNA (Hydroxy)Methylation

描述（申请人提供）：5-甲基化胞嘧啶（5 mC）关闭基因表达，5-羟甲基化胞嘧啶（5 hmC）打开基因表达。这两种表观遗传修饰被认为是社会行为因素调节基因表达的一种机制。然而，在以前的研究中使用的DNA甲基化与社会行为因素相关的实验室技术不能区分5 mC和5 hmC，并有其他限制。目前还没有任何关于5 hmC与社会行为因素相关的研究。迄今为止，DNA（羟基）甲基化的社会行为决定因素在很大程度上是未知的。遗传因素可以影响表观遗传修饰。双胞胎是遗传信息。双胞胎的共同双胞胎共享生殖系基因组序列[单卵双胞胎（MZ）共享100%，而双卵双胞胎（DZ）平均共享50%]，从父母继承的生殖系表观遗传修饰，以及共同的环境（即共同双胞胎之间共享的环境因素，包括年龄队列期效应，疾病家族史，母亲和其他家族影响，样本处理和储存条件）。这些共同的因素可以在双胞胎研究中通过相互比较双胞胎来唯一地控制，而不是在传统的流行病学研究中。在NHLBI双胞胎研究中，通过体格检查和面对面访谈，收集了不同衰老阶段的环境因素的详细数据，包括检查1至10时的社会行为、心理、饮食、生活方式、生化和临床因素。 5（1969-2000）;收集截至2010年12月31日的生命状态、死因和死亡年龄数据;在60-74岁时收集血沉棕黄层DNA样本[检查3（1986-87）]。我们已经开发了新的实验室技术，克服了上述技术限制，可以专门测量5 mC和5 hmC。因此，通过使用现有的资源在NHLBI双胞胎研究和新的实验室技术，我们已经开发，我们提出了一个共同的双胞胎研究的寿命的社会行为决定因素的系统性DNA（羟基）甲基化分离的遗传混杂。我们的长期研究目标是了解社会行为因素与基因组的相互作用，通过表观遗传修饰和由此产生的疾病后果和寿命，独立于种系。在这个R21项目中，我们将纳入NHLBI对白色男性双胞胎进行的双胞胎研究中的20对MZ和20对DZ男性双胞胎的代表性样本，这些样本在心血管死亡和死亡年龄方面不一致。这些双胞胎出生于1917年至1927年之间，在此期间，每1,000名活产婴儿中有2对男性MZ双胞胎和4对男性DZ双胞胎。这个R21项目的具体目标是：1）用我们的新实验室技术测量全基因组5 mC和5 hmC，2）鉴定差异5-甲基化基因组区域（DMR）和5-羟甲基化基因组区域（DhMR），3）在考试1中使用寿命社会行为数据探索DMR和DhMR的社会行为决定因素。我们的目标是为RFA-TW-13-002中所述的未来大规模研究生成初步数据。本研究的意义在于发展社会行为养生法以延长预期寿命。

DESCRIPTION (provided by applicant): The 5-methylated cytosine (5mC) turns off gene expression and the 5-hydroxymethylated cytosine (5hmC) turns it on. Both epigenetic modifications are thought to be one mechanism through which sociobehavioral factors regulate gene expression. However, the lab technique used in previous studies of DNA methylation related to sociobehavioral factors cannot distinguish 5mC from 5hmC and has other limitations. There is not any published study of 5hmC related to sociobehavioral factors. To date, the sociobehavioral determinants of DNA (hydroxy) methylation are largely unknown. Genetic factors can affect epigenetic modifications. Twins are genetically informative. Co-twins of a twin pair share germline genomic sequence [monozygotic twins (MZ) share 100% while dizygotic twins (DZ) on average share 50%)], germline epigenetic modifications inherited from parents, and common environment (i.e. environmental factors shared between co-twins, including age-cohort-period effects, family history of disease, maternal and other familial influences, sample processing and storage conditions). These shared factors can be uniquely controlled for in the co-twin study through comparing co-twins with each other, but not in a traditional epidemiologic study. In the NHLBI Twin Study, through physical examinations and in- person interviews, detailed data were collected on environmental factors from different aging stages, including sociobehavioral, psychological, dietary, lifestyle, biochemical, and clinical factors at exams 1 to 5 (1969-2000); data on vital status, cause of death, and age at death were collected through Dec 31, 2010; and buffy coat DNA samples were collected at age 60-74 years [exam 3 (1986-87)]. We have developed novel lab techniques that overcome the technical limitations mentioned above and can specifically measure both 5mC and 5hmC. Thus, by use of existing resources in the NHLBI Twin Study and the novel lab technique we have developed, we propose a co-twin study of the life-span sociobehavioral determinants of systemic DNA (hydroxy) methylation separated from genetic confounding. Our long-term research objective is to understand the interaction of sociobehavioral factors with the genome through epigenetic modifications and resultant disease consequences and the longevity, independent of the germline. In this R21 project, we will include a representative sample of 20 MZ and 20 DZ male twin pairs discordant for cardiovascular death and age at death from the NHLBI Twin Study of white male twins. These twins were born between 1917 and 1927, a period when 2 male MZ pairs and 4 male DZ pairs of twins were born per 1,000 live births. The specific aims of this R21 project are: 1) to measure genome-wide 5mC and 5hmC with our novel lab techniques, 2) to identify differentially 5-methylated genomic regions (DMRs) and 5- hydroxymethylated genomic regions (DhMRs), and 3) to explore sociobehavioral determinants of DMRs and DhMRs across the lifespan with life-span sociobehavioral data at exam 1. We aim to generate preliminary data for the future, large-scale study as stated in RFA-TW-13-002. The significance of our study lies in the development of sociobehavioral regimen to prolong the life expectancy.