Prenatal Exposure to Endocrine Disrupters, DNA Methylation, and Childhood Obesity

描述(由申请人提供)： 这项拟议研究的首要目标是利用新的表观基因组学方法调查产前暴露于EDCs：邻苯二甲酸盐和双酚A)与DNA甲基化模式和儿童肥胖的关系。该计划为环境流行病学家Allan Just博士提供导师培训(K99)和研究阶段(R00)，以成为表观流行病学的独立学术研究员。Just博士将接受由国际公认的科学家组成的指导团队的培训和指导，这些科学家在环境和表观流行病学、儿科和生物统计学方面具有专业知识，其中包括Andrea Baccarelli博士、Robert Wright博士和林希鸿博士。先前的研究已经证明，人类产前暴露可以改变胎儿的表观基因组，动物模型已经表明，邻苯二甲酸盐和双酚A影响后代的甲基化和肥胖风险。这项拟议的研究使用甲基化微阵列和新的基于测序的技术来研究两组人类儿童脐带血中的甲基化模式。一个表观基因组范围的甲基化微阵列(Illumina人类甲基化450K珠芯片)已经在120名儿童的脐带血DNA上进行，将测量跨越几乎所有已知基因的480K个单独位点的甲基化。统计模型将把这些甲基化测量与产前EDC暴露和4岁时的肥胖测量联系起来。这些模型使用了新的统计方法，考虑了多重比较，并反映了基因组中甲基化位置之间的相关性。在使用相同设计的独立队列(n=150)中进行重复，确保了研究结果的一致性和可推广性。在指导团队成员领导的现有赠款下，两个队列(称为PRISM和PRISM)已经收集或正在进行所有样本和肥胖测量。在R00阶段，一种尚未在大规模表观遗传流行病学研究中应用的新技术--靶向浓缩，将与亚硫酸氢盐治疗和下一代测序结合使用；这种方法将对已确定的感兴趣区域的所有甲基化位点产生新的高分辨率测量。这项研究应该提供更大的力量来检测EDC暴露、甲基化模式和儿童肥胖之间的联系。这种方法还可以通过比较更稀疏的全基因组平台的贡献与新的基于高密度测序的措施所发现的模式，来为未来的表观遗传学流行病学研究做出贡献。这项研究很重要，因为它量化了产前接触内皮细胞与人类胎儿组织甲基化模式相关的程度，然后将这些发现与儿童肥胖症联系起来。另一项创新是其使用两种不同的甲基化技术进行流行病学研究的技术。这项拟议中的工作用最先进的表观基因组学方法培训了Just博士，并以这种方式有助于理解内分泌干扰物对儿童健康的影响。

DESCRIPTION (provided by applicant): The overarching goal of the proposed research is to investigate the association of prenatal exposure to EDCs: phthalates and BPA) with DNA methylation patterns and childhood obesity using novel epigenomic approaches. The program provides mentored training (K99) and a research phase (R00) for Allan Just PhD, an environmental epidemiologist, to become an independent academic investigator in epigenetic epidemiology. Dr. Just will receive training and guidance from a mentoring team of internationally recognized scientists with specializations in environmental and epigenetic epidemiology, pediatrics, and biostatistics, including Dr. Andrea Baccarelli, Dr. Robert Wright and Dr. Xihong Lin. Prior research has demonstrated that human prenatal exposures can alter the fetal epigenome, and animal models have shown that phthalates and BPA impact methylation and obesity risk in the offspring. The proposed research uses methylation microarrays and new sequencing-based technologies to investigate methylation patterns in the umbilical cord blood of two cohorts of human children. An epigenome-wide methylation microarray (Illumina Human Methylation 450K BeadChip), already being conducted on umbilical cord blood DNA from 120 children, will measure methylation in 480K individual sites spanning almost all known genes. Statistical models will relate these methylation measures to prenatal EDC exposures and to measures of obesity at age 4. These models use new statistical approaches that account for multiple comparisons and reflect the dependence between methylation sites within the genome. Replication in an independent cohort (n=150), using the same design, assures that findings are consistent and generalizable. All samples and obesity measures are already collected or ongoing in the two cohorts (called PROGRESS and PRISM) under existing grants led by members of the mentoring team. In the R00 phase, a novel technique, targeted enrichment, which has not yet been applied in large-scale epigenetic epidemiologic studies, will be used in conjunction with bisulfite treatment and next generation sequencing; this approach will generate new high resolution measures of all methylation sites in identified regions of interest. This research should provide greater power to detect associations between EDC exposures, methylation patterns, and obesity in children. This approach may also contribute to future epigenetic epidemiological studies by comparing the contributions of the sparser, genome- wide platform with patterns found by the novel high density sequencing-based measures. This research is important because it quantifies the extent to which prenatal exposures to EDCs are associated with methylation patterns in human fetal tissue, and then links these findings to childhood obesity. Another innovation is its techniques to conduct epidemiologic studies with two different methylation technologies. The proposed work trains Dr. Just in state-of-the-art epigenomic approaches and in this way contributes to understanding of the impact of endocrine disruptors on children's health.