Effects of fetal bisphenol A exposure on mouse epigenome

描述(由申请人提供)：越来越多的证据表明，环境暴露会导致各种发育异常。相关分子途径的阐明为风险管理和预防方法提供了关键的见解。一种引起公众健康关注的化合物是双酚A(BPA)，通常用于各种塑料产品。人类受到广泛的暴露，暴露与肥胖、不孕不育、癌症、免疫系统降低和模式生物的行为异常有关。尽管广泛报道了双酚A暴露诱导的表型，但相关的分子机制尚不清楚。最近，几个实验室已经证明了BPA改变DNA甲基化的能力，提出表观遗传机制参与了BPA的发育作用。这位候选人的工作发现，暴露于双酚A对小鼠印记基因的表达和甲基化有影响。由于印记基因对胎儿、胎盘和出生后大脑的发育至关重要，而功能紊乱与人类发育障碍有关，研究表明，胎儿暴露于BPA有可能通过发育基因的表观遗传扰动影响发育。在目前的应用中，将分别使用甲基化DNA免疫沉淀、测序和使用微阵列，在产前暴露于BPA的小鼠的胚胎和胎盘组织中进行全基因组甲基化和表达研究。目标是确定相关的表观遗传途径。候选小鼠将包括缺乏雌激素受体α和β功能基因的小鼠，因为双酚A是一种雌激素，该项目旨在调查这些受体是否在表观基因组中介导双酚A效应。此外，候选人建议研究双酚A暴露对胎盘发育的影响，因为她之前的研究发现印记的CDKN1c基因存在显著的表观遗传失调。细胞周期抑制基因CDKN1c在小鼠胎盘发育中起关键作用，将对暴露于双酚A的小鼠胎盘进行组织学和免疫组织化学研究。目前的应用还建议研究组蛋白甲基转移酶EZH2及其相关的H3K27me3组蛋白标记在介导BPA诱导的发育异常中的全基因组和基因特异性作用，因为几个实验室已经发现从宫内暴露到BPA的小鼠各种组织中这些蛋白的异常表达。这些研究将利用染色质免疫沉淀，然后测序或随后进行qPCR。 公共卫生相关性：拟议的研究旨在通过调查双酚A暴露对胎儿表观基因组的影响并分析表观遗传扰动对哺乳动物发育的影响来阐明与环境暴露相关的表观遗传学机制。在拟议的研究中，老鼠将被用作模型系统，以确定人类疾病的潜在病因学和潜在的环境原因。

DESCRIPTION (provided by applicant): Increasing evidence has shown that environmental exposures cause various developmental abnormalities. Elucidation of the relevant molecular pathways provides critical insights into risks management and preventative approaches. A compound that has created a great public health concern is bisphenol A (BPA), commonly used in various plastic products. Humans are widely exposed and exposure is linked to obesity, infertility, cancer, reduced immune system and behavior anomalies in model organisms. Despite the widely reported phenotypes induced by BPA exposure, the relevant molecular mechanisms are unclear. Recently, several laboratories have demonstrated the ability of BPA to alter DNA methylation, proposing that epigenetic mechanisms are involved in BPA developmental action. The candidate's work has found effects of BPA exposure on the expression and methylation of mouse imprinted loci. As imprinted loci are critical for fetal, placental and postnatal brain development, and disrupted functions are linked to human developmental disorders, work demonstrates that fetal BPA exposure has the potential to impact development through epigenetic perturbations of developmental genes. In the current application, genome wide methylation and expression studies in the embryonic and placental tissues of mice exposed prenatally to BPA will be undertaken using methylated DNA immunoprecipitation followed by sequencing and using microarrays, respectively. The goal is to identify the relevant epigenetic pathways. The candidate will include mice lacking the functional genes for estrogen receptor alpha and beta as BPA is an estrogen and the project aims to investigate if these receptors mediate BPA effects in the epigenome. Additionally, the candidate proposes to study the effects of BPA exposure in placental development as her previous studies revealed significant epigenetic dysregulation of the imprinted Cdkn1c gene. The cell cycle inhibitor Cdkn1c gene plays a critical role in mouse placental development and histological and immunohistochemical studies will be conducted to analyze placentas from BPA-exposed mice. The current application also proposes to investigate the genome wide and gene specific roles of the histone methyltransferase EZH2 and its relevant H3K27me3 histone mark in mediating BPA-induced developmental abnormalities as several laboratories have found aberrant expression of the proteins in various tissues from mice exposed in utero to BPA. These studies will utilize chromatin immunoprecipitation followed by sequencing or followed by qPCR. Public Health Relevance: The proposed studies aim to elucidate epigenetic mechanisms related to environmental exposures by investigating effects of bisphenol A exposure on the fetal epigenome and analyzing the consequences of epigenetic perturbations on mammalian development. The mouse will be used as a model system in the proposed studies to determine the potential etiology of human diseases with underlying environmental causes.