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

描述（由申请人提供）： 拟议研究的总体目标是使用新的表观基因组方法研究产前暴露于EDCs（邻苯二甲酸酯和BPA）与DNA甲基化模式和儿童肥胖的关联。该计划为环境流行病学家Allan Just博士提供指导培训（K99）和研究阶段（R 00），成为表观遗传流行病学的独立学术调查员。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，这些科学家专门从事环境和表观遗传流行病学，儿科学和生物统计学，包括Andrea Baccarelli博士，Robert Wright博士和Xihong Lin博士。 先前的研究已经证明，人类产前暴露可以改变胎儿表观基因组，动物模型表明邻苯二甲酸酯和BPA影响后代的甲基化和肥胖风险。这项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 Human Methylation 450 K BeadChip）已经在120名儿童的脐带血DNA上进行，将测量几乎所有已知基因的480 K个位点的甲基化。统计模型将把这些甲基化测量与产前EDC暴露和4岁时肥胖的测量相关联。这些模型使用了新的统计方法，可以解释多重比较，并反映基因组内甲基化位点之间的依赖性。在一个独立的队列（n=150），使用相同的设计，复制，确保调查结果是一致的和可推广的。所有样本和肥胖测量都已经收集或正在两个队列（称为PROGRESS和PRISM）中进行，由指导团队成员领导的现有赠款。在R 00阶段，一种新的技术，靶向富集，尚未应用于大规模的表观遗传流行病学研究，将与亚硫酸氢盐处理和下一代测序结合使用;这种方法将产生新的高分辨率措施的所有甲基化位点在确定的区域感兴趣。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关联。这种方法还可以通过比较稀疏的全基因组平台的贡献与通过新的基于高密度测序的措施发现的模式来促进未来的表观遗传流行病学研究。 这项研究很重要，因为它量化了产前暴露于EDCs与人类胎儿组织中甲基化模式相关的程度，然后将这些发现与儿童肥胖联系起来。另一个创新是它使用两种不同的甲基化技术进行流行病学研究的技术。拟议的工作培训博士只是在国家的最先进的表观基因组方法，并以这种方式有助于了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.