Tetrabromobisphenol A (TBBPA) as a modulator of tryptophan catabolism and maternal-fetal health

摘要 越来越多的证据表明，暴露于人造化学品会破坏人类的生殖能力。 健康阐明相关机制对于制定干预战略至关重要。的目标 拟开展的工作是研究内分泌干扰物（EDCs）在调节色氨酸中的作用 catastrophic作为一种新的机制，环境污染引起的不良妊娠结局。 色氨酸是妊娠期间母体免疫耐受的调节剂。无法降解 怀孕母亲中的色氨酸与很大比例的人类流产，先兆子痫， 早产这个过程的一个关键事件是胎盘Ido 1基因的激活，该基因编码一个 主要的葡聚糖降解酶。我们的实验室已经表明，在子宫内暴露于一种代表性的 EDC，四溴双酚A（TBBPA），减少胎盘Ido 1基因和蛋白质表达，并与 胎儿吸收率增加。在本提案中，我们希望调查接触TBBPA是否会改变 通过干扰色氨酸催化剂和降低母胎免疫耐受来影响妊娠结局。我们 将雌性小鼠暴露于环境相关剂量的TBBPA（即，5、50和500 µg/kg bw/天） 交配、交配期间和整个妊娠期，并分析妊娠小鼠和孕体。我们 我希望通过分析一个子集来确定暴露是否与母体免疫力降低有关， 免疫抑制性T细胞称为“调节性T细胞”或“T细胞”。使用流式细胞术，我们将确定Treg 对照组和暴露妊娠小鼠的蜕膜和子宫中的数量。色氨酸催化剂增加 在怀孕期间与母体甲状腺激素的增加有关。作为母亲的高睾酮支持 妊娠维持，我们预期暴露于TBBPA的小鼠具有降低的TdR。以确定是否 TBBPA暴露的妊娠小鼠中胎儿丢失率增加与母体Treg减少有因果关系 编号，我们将使用来自供体Foxp 3-GFP小鼠的TcR进行过继转移研究。另外我们 将进行液相色谱和质谱分析，以测量色氨酸的水平， 在妊娠的连续阶段中，其在妊娠母体、胎儿和胎盘中的卡替林。我们希望 阐明TBBPA诱导的对母体免疫力和妊娠结局的影响是否与 色氨酸催化剂水平异常最后，我们的初步研究表明，Ido 1基因受 基因组印记我们将研究TBBPA暴露对Ido 1位点印迹调节的影响， 分析等位基因特异性基因表达、DNA甲基化和/或翻译后组蛋白修饰 通过定量真实的时间PCR、亚硫酸氢盐测序和染色质免疫沉淀。

ABSTRACT Accumulating evidence has demonstrated that exposure to man-made chemicals disrupts human reproductive health. Elucidation of the relevant mechanisms is critical for designing intervention strategies. The goal of the proposed work is to investigate the role of endocrine disrupting chemicals (EDCs) in modulating tryptophan catabolism as a novel mechanism of environmental exposure-induced adverse pregnancy outcomes. Tryptophan catabolism is a regulator of maternal immune tolerance during pregnancy. Failure to degrade tryptophan in the pregnant mother is linked to a significant proportion of human miscarriages, preeclampsia, and premature labor. A key event of this process is activation of the placental Ido1 gene that encodes for a major tryptophan-degrading enzyme. Our laboratory has shown that in utero exposure to a representative EDC, tetrabromobisphenol A (TBBPA), reduces placental Ido1 gene and protein expression, and is linked to increased rates of fetal resorption. In this proposal, we wish to investigate whether exposure to TBBPA alters pregnancy outcomes by perturbing tryptophan catabolism and reducing maternal-fetal immune tolerance. We will expose female mice to environmentally relevant doses of TBBPA (i.e., 5, 50, and 500 µg/kg bw/day) prior to mating, during mating, and throughout pregnancy, and analyze the pregnant mice and conceptuses. We wish to determine if exposures are linked to reduced maternal immunity by analyzing a subset of immunosuppressive T cells called “regulatory T cells” or “Tregs”. Using flow cytometry, we will determine Treg number in the decidua and uterus of controls and exposed pregnant mice. Increased tryptophan catabolism during pregnancy has been linked to expansion of maternal Tregs. As elevated maternal Tregs favor pregnancy maintenance, we anticipate that TBBPA-exposed mice have reduced Tregs. To determine if increased rate of fetal loss in TBBPA-exposed pregnant mice is causatively linked to reduced maternal Treg number, we will perform an adoptive transfer study using Tregs from donor Foxp3-GFP mice. Additionally, we will perform liquid chromatography and mass spectrometry-based assays to measure levels of tryptophan and its catabolites in the pregnant dam, fetus, and placenta during sequential stages of pregnancy. We wish to elucidate whether TBBPA-induced effects on maternal immunity and pregnancy outcomes are linked to abnormal levels of tryptophan catabolites. Finally, our preliminary studies show that the Ido1 gene is subject to genomic imprinting. We will investigate effects of TBBPA exposure on imprinting regulation of the Ido1 locus by analyzing allele-specific gene expression, DNA methylation and/or posttranslational histone modifications through quantitative real time PCR, bisulfite sequencing, and chromatin immunoprecipitation.