Impact of the Placenta Barrier on Fetal Nutrition and Growth Restriction

项目摘要/摘要 胎儿生长受限(FGR)是一种严重影响婴儿死亡率和发病率的疾病。 尽管人们对FGR的病因知之甚少，但环境和职业暴露一直是 与其发病机制有关。已发现环境毒物镉(Cd)的可测量水平 在99%的孕妇中。这种广泛的暴露是重要的，因为Cd已被证明在 并在人类流行病学研究中与FGR有关。CD以胎盘的关键功能为靶点 致FGR。在健康的条件下，胎盘对母体和母体之间的营养交换起着关键的调节作用 胎儿循环同时也限制了毒物的转移。外排泵，包括乳腺癌 抗性蛋白(人BCRP/啮齿动物BCRP)高表达在母体面对膜上。 因此，通过降低胎盘(和胎儿)中的异种生物浓度来帮助胎儿保护。我们的 实验室已证明，体外过表达人BCRP基因可降低细胞内CD 浓度，并提供对镉细胞应激和毒性的抵抗力。然而，目前还不清楚 胎盘中的BCRP对体内镉毒性有调节作用。为了开始解决这个问题，我开发了一个模型 对Cd诱导的野生型小鼠FGR的影响。初步数据显示，伴随着胎儿体重的下降 通过给怀孕小鼠注射氯化镉后胎儿血糖水平的下降。这些数据与之前的一致 研究表明，营养转运蛋白是Cd诱导FGR的分子靶标。我的中心假设是 BCRP转运蛋白功能完全丧失或降低的胎盘是CD的高风险因素 积聚，导致葡萄糖转移和利用受损，严重的胎儿生长受限。这就做 利用两个转基因小鼠品系来验证这一假设：1)没有BCRP表达的BCRP-/-小鼠和2) BCRP-Q140K小鼠，一种与人类功能丧失Q141K变体同源的CRISPR模型 总结了临床观察到的BCRP功能减退。我期待着来自BCRP的胎盘-/-和 与野生型(BCRP+/+)小鼠相比，BCRP-Q140K小鼠对Cd的积累和毒性更敏感 这将在两个具体目标上进行测试。为了这个奖学金，我将完成一系列关于啮齿动物和 胎盘的临床解剖病理学，生殖生物学和毒理学的课程和工作坊， 以及动手实验技术，包括电感耦合等离子体质谱和免疫组织化学。大部分的培训 活动将在罗格斯大学通过毒理学跨学科联合研究生项目进行。 总体而言，这项拟议的研究计划将促进我成为一名独立的研究科学家 通过作为博士论文一部分完成的研究。

PROJECT SUMMARY/ABSTRACT Fetal growth restriction (FGR) is a critical disease that contributes significantly to infant mortality and morbidity. Although the etiology of FGR is poorly understood, environmental and occupational exposures have been implicated in its pathogenesis. Measurable levels of the environmental toxicant cadmium (Cd) have been found in >99% of pregnant women. This widespread exposure is important as Cd has been shown to induce FGR in rodents and linked to FGR in human epidemiological studies. Cd targets key functions of the placenta that lead to FGR. Under healthy conditions, the placenta critically regulates nutrient exchange between the maternal and fetal circulation while at the same time restricts the transfer of toxicants. Efflux pumps, including the breast cancer resistance protein (human BCRP/rodent Bcrp), are highly expressed on the maternal-facing membrane of placentas and thus aid in fetal protection by lowering placental (and fetal) xenobiotic concentrations. Our laboratory has demonstrated that in vitro overexpression of the human BCRP gene lowers intracellular Cd concentrations and confers resistance against Cd cellular stress and toxicity. However, it is unknown whether Bcrp in the placenta can regulate Cd toxicity in vivo. To begin to address this question, I have developed a model of Cd-induced FGR in wild-type mice. Preliminary data reveal a decrease in fetal weights that is accompanied by a decline in fetal glucose levels following administration of CdCl2 to pregnant mice. These data align with prior studies suggesting that nutrient transporters are molecular targets of Cd-induced FGR. My central hypothesis is that placentas with a complete loss or reduction in Bcrp transporter function are at a heightened risk of Cd accumulation which leads to impaired glucose transfer and utilization and severe fetal growth restriction. I will utilize two transgenic mouse lines to test this hypothesis: 1) Bcrp-/- mice that have no Bcrp expression and 2) Bcrp-Q140K mice, a CRISPR model that is orthologous to the human loss-of-function Q141K variant and recapitulates the reduced functioning of BCRP observed clinically. I anticipate that placentas from Bcrp-/- and Bcrp-Q140K mice will be more sensitive to Cd accumulation and toxicity compared to wild-type (Bcrp+/+) mice which will be tested in two specific aims. For this fellowship, I will complete a series of training in rodent and clinical anatomic pathology of the placenta, coursework and workshops in reproductive biology and toxicology, and hands-on experimental techniques including ICP/MS and immunohistochemistry. The majority of the training activities will occur at Rutgers University through the interdisciplinary Joint Graduate Program in Toxicology. Overall, this proposed research plan will enhance my development into an independent research scientist through studies completed as part of a Ph.D. dissertation.