Germline transmission of epigenetic alterations to offspring induced by bisphenol A exposure

我们研究计划的总体目标是确定环境雌激素化学品的影响 原始生殖细胞（PGCs）中DNA甲基化特征的模式和性别特异性， 后代以及变化是否与特定的表型异常相关。所有PGCs 在性别决定时经历表观遗传重编程。在全球DNA擦除之后， 甲基化模式，从头甲基化开始允许生殖细胞中受控的基因表达模式 以特定性别的方式。已经发现生殖细胞重编程的这个窗口容易受到 环境化学污染。我们的假设是：1）环境化学物质建立DNA甲基化 PGC基因组中对整体DNA去甲基化过程具有抗性的标记; 2）这些化学标记 诱导标记在有丝分裂和减数分裂中是稳定的，因此在卵子和精子中得以维持;以及3） DNA甲基化模式的特定改变通过细菌传递给后代， 线，并在从受精卵发育的每个细胞中检测到。拟议的研究将侧重于 人类和野生动物接触的雌激素化学物质双酚A（BPA）。BPA诱导 已经在各种动物模型中报道了不利的健康影响，包括跨代不利的健康影响。 结果，如小鼠的社会互动减少和斑马鱼的心脏病。我们已经展示了在 青鳉鱼F0胚胎暴露于BPA导致跨代异常： F2和F3代，并降低胚胎存活在F3和F4代。拟议的研究旨在 在识别BPA诱导的生殖细胞表观遗传特征，导致跨代遗传 表型与环境相关的剂量与青鳉鱼模型（青鳉）。我们有两 具体目标。具体目标1将检验BPA建立独特DNA甲基化的假设 在雄性和/或雌性的原始生殖细胞中存在对重编程具有抗性的标记。具体目标 2将检验BPA诱导的DNA甲基化特征在卵子和精子中都保留的假设 以及F1（直接暴露于F0胚胎中）、F2和F3（不直接暴露于F0胚胎中）中PGCs的旁路重编程 暴露）世代。这一目标将集中在生殖系跨代传播过程中的事件， 表观遗传标记从成虫到下一代（F2和F3）。结合起来，这两个具体目标 应该在F0和F1 - F3的原始生殖细胞中揭示独特的BPA诱导的表观遗传标记 后代这项拟议的R21研究的结果将用于开发R 01项目， 鉴定额外的表观遗传控制机制，如组蛋白修饰和microRNA， 潜在的环境雌激素诱导的跨代疾病表型及其相应的 在青鳉和小鼠中，超过F3的几代的表观遗传生物标志物。此程序将 最终为人类跨代疾病的表观遗传机制带来新的见解。

The overall goal of our research program is to determine the effects of environmental estrogenic chemicals on patterns and gender specificity of DNA methylation signatures in primordial germ cells (PGCs) that pass to subsequent generations and whether changes are associated with specific phenotypic abnormalities. All PGCs undergo epigenetic reprogramming at the time of sex determination. Following global erasure of DNA methylation patterns, a de novo methylation starts allowing a controlled gene expression pattern in germ cells in a gender specific manner. This window of germ cell reprogramming has been found to be susceptible to environmental chemical insult. Our hypothesis is that: 1) environmental chemicals establish DNA methylation marks in the PGC genome that are resistant to global DNA demethylation processes; 2) these chemically induced marks are mitotically and meiotically stable, and as such are maintained in eggs and sperm; and 3) specific alterations in DNA methylation patterns are transmitted to subsequent generations through the germ line and are detectable in every cell that develops from the zygote. The proposed study will focus on an estrogenic chemical bisphenol A (BPA) to which humans and wildlife are exposed. The ability of BPA to induce adverse health effects has been reported in various animal models, including transgenerational adverse outcomes, such as reduced social interaction in mice and heart disorders in zebrafish. We have shown in medaka fish that F0 embryo exposure to BPA causes transgenerational abnormalities: reduced fertilization at F2 and F3 generation and reduced embryo survival at F3 and F4 generation. The proposed studies are aimed at identifying BPA-induced epigenetic signatures in germline cells leading to transgenerational inheritance of phenotypes at environmentally relevant doses with the medaka fish model (Oryzias latipes). We have two specific aims. Specific Aim 1 will test the hypothesis that BPA establishes unique DNA methylation signatures in primordial germ cells of males and/or females that are resistant to reprogramming. Specific Aim 2 will test the hypothesis that BPA-induced DNA methylation signatures are retained in both egg and sperm and bypass reprogramming of PGCs in the F1 (directly exposed in the F0 embryos), F2, and F3 (not directly exposed) generations. This aim will focus on events during germline transgenerational transmission of epigenetic marks from adults to the subsequent generation (F2 and F3). Combined, these two specific aims should reveal unique BPA-induced epigenetic marks in the primordial germ cells in F0 and then F1 – F3 offspring. Results from this proposed R21 study will be used to develop a R01 project directed toward identification of additional epigenetic control mechanisms, such as histone modifications and microRNAs, underlying environmental estrogen-induced transgenerational disease phenotype and their corresponding epigenetic biomarkers across several generations beyond F3 in both medaka and mice. This program will ultimately bring new insights into epigenetic mechanisms underlying transgenerational diseases in humans.