Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, Michigan, USA.
BMC Genomics. 2014 Jan 17;15:30. doi: 10.1186/1471-2164-15-30.
Environmental factors during perinatal development may influence developmental plasticity and disease susceptibility via alterations to the epigenome. Developmental exposure to the endocrine active compound, bisphenol A (BPA), has previously been associated with altered methylation at candidate gene loci. Here, we undertake the first genome-wide characterization of DNA methylation profiles in the liver of murine offspring exposed perinatally to multiple doses of BPA through the maternal diet.
Using a tiered focusing approach, our strategy proceeds from unbiased broad DNA methylation analysis using methylation-based next generation sequencing technology to in-depth quantitative site-specific CpG methylation determination using the Sequenom EpiTYPER MassARRAY platform to profile liver DNA methylation patterns in offspring maternally exposed to BPA during gestation and lactation to doses ranging from 0 BPA/kg (Ctr), 50 μg BPA/kg (UG), or 50 mg BPA/kg (MG) diet (N = 4 per group). Genome-wide analyses indicate non-monotonic effects of DNA methylation patterns following perinatal exposure to BPA, corroborating previous studies using multiple doses of BPA with non-monotonic outcomes. We observed enrichment of regions of altered methylation (RAMs) within CpG island (CGI) shores, but little evidence of RAM enrichment in CGIs. An analysis of promoter regions identified several hundred novel BPA-associated methylation events, and methylation alterations in the Myh7b and Slc22a12 gene promoters were validated. Using the Comparative Toxicogenomics Database, a number of candidate genes that have previously been associated with BPA-related gene expression changes were identified, and gene set enrichment testing identified epigenetically dysregulated pathways involved in metabolism and stimulus response.
In this study, non-monotonic dose dependent alterations in DNA methylation among BPA-exposed mouse liver samples and their relevant pathways were identified and validated. The comprehensive methylome map presented here provides candidate loci underlying the role of early BPA exposure and later in life health and disease status.
围产期环境因素可能通过改变表观基因组来影响发育可塑性和疾病易感性。先前的研究表明，发育过程中接触内分泌活性化合物双酚 A（BPA）会导致候选基因座的甲基化改变。在这里，我们通过母体饮食，首次对围产期暴露于多种剂量 BPA 的小鼠后代肝脏中的 DNA 甲基化谱进行了全基因组特征描述。
使用分层聚焦方法，我们的策略从使用基于甲基化的下一代测序技术的无偏广泛 DNA 甲基化分析开始，然后使用 Sequenom EpiTYPER MassARRAY 平台进行深入的定量特定 CpG 甲基化测定，以描述在妊娠和哺乳期暴露于 BPA 的后代肝脏 DNA 甲基化模式，剂量范围从 0 BPA/kg（Ctr）、50μg BPA/kg（UG）或 50mg BPA/kg（MG）饮食（每组 4 只）。全基因组分析表明，围产期暴露于 BPA 后 DNA 甲基化模式呈非单调变化，与先前使用多种剂量 BPA 且结果呈非单调变化的研究结果一致。我们观察到在 CpG 岛（CGI）海岸的改变甲基化区域（RAM）富集，但在 CGIs 中几乎没有 RAM 富集的证据。启动子区域的分析确定了数百个新的 BPA 相关甲基化事件，并且验证了 Myh7b 和 Slc22a12 基因启动子中的甲基化改变。使用比较毒理学基因组数据库，确定了先前与 BPA 相关基因表达变化相关的一些候选基因，并且基因集富集测试确定了涉及代谢和刺激反应的表观遗传失调途径。
在这项研究中，鉴定并验证了 BPA 暴露的小鼠肝样本中 DNA 甲基化的非单调剂量依赖性改变及其相关途径。本文提供的综合甲基组图谱为早期 BPA 暴露及其对生命后期健康和疾病状态的作用提供了候选基因座。
