Perinatal Exposures, Tissue- and Cell-specific Epigenomics, & Lifecourse Outcomes

 描述（由申请人提供）：生命早期接触有毒物质会对动物和人类的健康结果产生不利影响，部分原因是表观遗传机制（例如DNA甲基化）。研究还表明，暴露对表观基因组的影响可能是组织甚至细胞特异性的。然而，毒物的表观遗传流行病学分析通常限于生物学上可用的或“替代”（例如血液、唾液）样本，这些样本可作为暴露靶组织表观遗传状态的替代样本。虽然外周DNA的甲基化可能无法反映所有组织的甲基化，但它已被用作与疾病和暴露相关的生物标志物。使用双酚A和邻苯二甲酸酯（如DEHP）作为代表性毒物，我们的总体目标是利用小鼠模型来评估与围产期暴露和疾病结局相关的组织和细胞特异性表观遗传改变，包括在人类中无法评估的组织。我们通过利用作为密歇根州NIEHS/EPA资助的儿童环境健康P01中心的一部分资助的组织来利用资源，其中靶组织的表观遗传分析侧重于候选亚稳态表观等位基因和印迹基因，这两组基因座最容易受到环境变化的影响。在TaRGET II U 01中，我们将全基因组分析扩展到11种组织和细胞类型，以绘制DNA甲基化（5 mC），羟甲基化（5 hmC）和基因表达，努力为环境重点的表观遗传流行病学研究提供信息。我们使用样本量来检测性别差异，并在出生后第22天的围产期暴露后立即在三个胚层的靶组织中进行甲基化组和转录组分析（脑和乳腺来自外胚层，肾来自中胚层，肝来自内胚层）和与人类相关的替代组织中（毛发、外周血白细胞和粪便），以及在8个月龄时纵向地观察，以鉴定持续到成年期的暴露依赖性表观遗传变化。利用我们团队在细胞特异性表观遗传学方面的专业知识，我们还包括4个纯化的细胞群，以进一步比较靶细胞和替代细胞。最终，我们试图确定一个子集的组织独立的不稳定基因，这代表了地区的表观基因组脆弱的生命早期，并可能会询问，与使用替代组织。

 DESCRIPTION (provided by applicant): Toxicant exposures early in life adversely affect health outcomes in both animals and humans, in part due to epigenetic mechanisms (e.g. DNA methylation). Studies also indicate that exposures' impact on the epigenome can be tissue and even cell specific. Yet, epigenetic epidemiology analysis of toxicants is often limited to biologically available or "surrogate" (e.g. blood, saliva) samples, which serve as proxies for epigenetic status in tissues targeted by exposures. While methylation of peripheral DNA may not mirror that of all tissues, it has been used as a biomarker associated with both disease and exposures. Using bisphenol A and phthalates (e.g. DEHP) as representative toxicants, our overall objective is to utilize mouse models to evaluate tissue- and cell-specific epigenetic alterations associated with perinatal exposures and disease outcomes, including tissues not feasibly assessed in humans. We leverage resources by utilizing tissues funded as part of the Michigan NIEHS/EPA-funded Children's Environmental Health P01 Center in which epigenetic analysis in target tissues focuses on candidate metastable epialleles and imprinted genes, two sets of loci most vulnerable to environmental changes. Within TaRGET II U01, we will extend analysis genome- wide to 11 tissue and cell types to map DNA methylation (5mC), hydroxymethylation (5hmC), and gene expression in an effort to inform epigenetic epidemiology studies with an environmental focus. We use sample sizes powered to detect sex differences and conduct methylome and transcriptome analyses immediately following perinatal exposure at post-natal day 22 in target tissues from the three germ layers (brain & breast from ectoderm, kidney from mesoderm, & liver from endoderm) and in surrogate tissues of human relevance (hair, peripheral blood leukocytes, & stool), as well as longitudinally at 8 months of age to identify exposure- dependent epigenetic changes that persist into adulthood. Capitalizing on our team's expertise in cell-specific epigenetics, we also include 4 purified cell populations to furthr compare target cells to surrogates. Ultimately, we seek to identify a subset of tissue-independent labile genes, which represent regions of the epigenome vulnerable early in life, and may be interrogated, with the use of surrogate tissues.