Environmental Modulation of Epigenetic Reprogramming in Pluripotent Cells

描述（由申请人提供）：表观遗传重编程，特别是DNA甲基化的重置，是胚胎着床前发育和胚胎种系中的关键事件。母亲饮食的改变或接触环境污染物可破坏胎儿的表观遗传重编程，导致妊娠失败、发育障碍或成人发病疾病，但其潜在的分子机制尚不清楚。重要的是要填补这一空白，以便制定知情的产妇饮食和接触环境毒素的安全标准，并了解成人发病疾病的表观遗传基础。研究人员研究的长期目标是了解胚胎发育的表观遗传调控。本应用程序的目的是确定维生素C在胚胎表观遗传重编程中的作用。人类完全依靠饮食来获取维生素C，这是几个生理过程所必需的。我们实验室最近的研究结果表明，维生素C在直接调控表观遗传重编程中具有新的作用，特别是在多能干细胞中DNA去甲基化和种系基因的激活中。这一提议将验证维生素C是多能干细胞和胎儿种系表观遗传重编程的关键环境调节剂这一创新假设。具体目的是：1)确定维生素C在表观遗传重编程中的作用机制。研究人员将测试维生素C作为Tet酶在种系基因启动子上生成5-羟甲基胞嘧啶的潜在辅助因子的作用；2)确定暴露于维生素C对多能干细胞功能的影响。将评估维生素C在体外调节多能干细胞特异性功能中的作用；3)确定维生素c介导的表观遗传重编程的易感窗口（WOS）。研究人员将使用一个经过验证的维生素C缺乏症小鼠模型来确定表观遗传重编程在体内发生时对维生素C的WOS。该研究有望为妊娠期表观遗传重编程的饮食和环境调节提供基础的新见解，在毒理学、母胎医学、生殖生物学和癌症方面具有重要影响。

DESCRIPTION (provided by applicant): Epigenetic reprogramming, and specifically the resetting of DNA methylation, is a key event during preimplantation development and in the fetal germline. Changes in the maternal diet or exposure to environmental contaminants can disrupt fetal epigenetic reprogramming and lead to pregnancy failure, developmental disorders or adult-onset disease, but the underlying molecular mechanisms remain unknown. It is important to fill this gap in order to develop informed safety standards for maternal diet and exposure to environmental toxins, and understand the epigenetic basis of adult-onset disease. The long-term goal of the investigators' research is to understand the epigenetic regulation of embryonic development. The objective of this application is to define the role of Vitamin C in epigenetic reprogramming in the embryo. Humans rely entirely on their diet for Vitamin C, which is essential for several physiological processes. Recent findings from our lab indicate that Vitamin C has a novel role in the direct regulation of epigenetic reprogramming, and specifically in DNA de-methylation and activation of germline genes in pluripotent stem cells. This proposal will test the innovative hypothesis that Vitamin C is a critical environmental regulator of epigenetic reprogramming in pluripotent stem cells and the fetal germline. The specific aims are: 1) to determine the mechanism of action of Vitamin C in epigenetic reprogramming. The investigators will test the role of Vitamin C as a potential co-factor of Tet enzymes in the generation of 5-hydroxymethyl-Cytosine at the promoters of germline genes; 2) to determine the functional consequences of exposure to Vitamin C in pluripotent stem cells. The role of Vitamin C will be assessed in the regulation of functions specific to pluripotent stem cells in vitro; and 3) to defie the Windows of Susceptibility (WOS) of Vitamin C-mediated epigenetic reprogramming. The investigators will use a validated mouse model of Vitamin C deficiency to determine the WOS to Vitamin C during the stages when epigenetic reprogramming occurs in vivo. This research is expected to provide fundamental new insights into the dietary and environmental modulation of epigenetic reprogramming during gestation, with significant impact in toxicology, maternal-fetal medicine, reproductive biology and cancer.