Glucose metabolism in the fetal liver during hypoxia

项目摘要 这项建议的目的是测试妊娠晚期缺氧对胎儿的代谢和分子影响， 胎肝葡萄糖生成率（GPR）的早期激活。这很重要，因为怀孕 并发胎盘缺血性疾病，特别是胎盘功能不全引起的宫内生长 宫内发育迟缓（IUGR）使胎儿暴露于缺氧。我们已经表明，胎儿肝脏在IUGR增加， GPR对胰岛素的抑制具有抗性，是糖尿病发病机制的标志。IUGR胎儿也有 有限的葡萄糖氧化（GOX）能力，这可能会重新引导碳GPR。我们在IUGR中发布的数据 胎儿支持FOXO 1增加PCK 1以增加葡萄糖产生和PDK 4以限制葡萄糖产生的机制。 葡萄糖氧化重要的是，PCK 1和PDK 4的表达与胎儿pO 2呈负相关 表明缺氧是GPR和GOX的共同调节剂。我们的目标是了解缺氧诱导的 胎儿GPR的早期激活机制。我们假设胎儿缺氧将FOXO 1锁定在一个 活跃的核国家该事件导致PCK 1增加，从而增加GPR，以及PDK 4增加， 减少GOX，为GPR重定向碳底物，维持胎儿的葡萄糖和能量供应。我 将通过精确降低胎儿动脉pO 2来选择性地测试妊娠晚期缺氧对胎儿肝脏的影响 从0.8到0.9妊娠，升高到11-14 mmHg，这模拟了年龄匹配的IUGR胎儿的胎儿pO 2。目标1将 确定胎儿缺氧在GPR增加和GOX减少的发展中的作用， 调节胎儿这种代谢适应的分子机制。我要测量葡萄糖摄取量， 利用，生产和氧化率在活胎中使用代谢示踪剂研究。在胎儿肝脏里，我会 测量FOXO 1信号通路，并期望确定缺氧诱导FOXO 1活化增加 PCK 1和PDK 4。将确定胎仔肝脏代谢组的协调变化，以支持增加 用于GPR的碳基底。目的2将确定胎肝细胞对GPR和GOX的底物偏好 是由缺氧引起的我将测量原代胎肝细胞的耗氧率，以确定 缺氧期间氨基酸优先氧化，以补偿GOX的减少。我会审问你 低氧诱导的FOXO 1信号通过选择性诱导低氧和抑制Gox， FOXO 1.预期结果：胎儿缺氧将激活GPR并通过FOXO 1特异性限制GOX 机制等影响：我将定义胎儿代谢和分子适应缺氧，这是关键， 了解缺氧如何促进胎儿肝脏中GPR的早期激活，建立直接风险， 患上2型糖尿病的风险。伴随这些研究目标的代谢训练计划将 提供全身（胎儿）、组织（肝脏）代谢和分子技术的综合培训， 细胞（肝细胞）水平，以促进我的独立性，作为一个研究人员在胎儿代谢。

PROJECT SUMMARY The goal of this proposal is to test the metabolic and molecular effects of hypoxia during late gestation on the early activation of fetal hepatic glucose production rate (GPR). This is important because pregnancies complicated by placental ischemic disease and specifically placental insufficiency induced intrauterine growth restriction (IUGR) expose the fetus to hypoxia. We have shown that the fetal liver during IUGR has increased GPR, which is resistant to suppression by insulin, a hallmark of diabetes pathogenesis. The IUGR fetus also has limited glucose oxidation (GOX) capacity, which may re-direct carbon for GPR. Our published data in the IUGR fetus supports a mechanism whereby FOXO1 increases PCK1 to increase glucose production, and PDK4 to limit glucose oxidation. Importantly, the expression of both PCK1 and PDK4 are inversely related to fetal pO2 indicating that hypoxia is a common regulator of GPR and GOX. Our goal is to understand the hypoxia induced mechanisms for the early activation of fetal GPR. We hypothesize that fetal hypoxia locks FOXO1 into an active nuclear state. This event produces increased PCK1, which increases GPR, and increased PDK4, which decreases GOX to re-direct carbon substrates for GPR and maintain glucose and energy supply for the fetus. I will selectively test the effects of late gestation hypoxia on the fetal liver by precisely reducing fetal arterial pO2 to 11-14 mmHg from 0.8 to 0.9 gestation, which mimics fetal pO2 in age-matched IUGR fetuses. Aim 1 will determine the role of fetal hypoxia in the development of increased GPR and decreased GOX and define novel molecular mechanisms regulating this metabolic adaptation in the fetus. I will measure glucose uptake, utilization, production, and oxidation rates in the alive fetus using metabolic tracer studies. In the fetal liver, I will measure the FOXO1 signaling pathway and expect to identify that hypoxia induces FOXO1 activation to increase PCK1 and PDK4. Coordinated changes in the fetal hepatic metabolome will be determined to support increased carbon substrates for GPR. Aim 2 will determine the fetal hepatocyte substrate preference for GPR and GOX produced by hypoxia. I will measure the oxygen consumption rate of primary fetal hepatocytes to determine if amino acids are preferentially oxidized during hypoxia to compensate for decreased GOX. I will interrogate how hypoxia-induced FOXO1 signaling coordinates GPR and GOX by selectively inducing hypoxia and inhibiting FOXO1. Expected outcomes: Fetal hypoxia will activate GPR and limit GOX through FOXO1 specific mechanisms. Impact: I will define the fetal metabolic and molecular adaptations to hypoxia, which is key to understanding how hypoxia promotes early activation of GPR in the fetal liver, establishing a direct risk for developing type 2 diabetes later in life. The metabolism training plan accompanying these research aims will provide integrative training in metabolic and molecular techniques at the whole-body (fetal), tissue (liver), and cellular (hepatocyte) level to promote my independence as a researcher in fetal metabolism.