Glucose metabolism in the fetal liver during hypoxia

项目总结 这项提议的目的是测试妊娠晚期低氧对小鼠的代谢和分子水平的影响。 早期激活胎儿肝脏葡萄糖产生率(GPR)。这一点很重要，因为怀孕 合并胎盘缺血性疾病，特别是胎盘功能不全导致宫内生长 宫内发育迟缓(IUGR)使胎儿暴露在低氧环境中。我们已经证明在IUGR期间胎儿的肝脏已经增加 GPR抵抗胰岛素抑制，这是糖尿病发病机制的一个标志。IUGR胎儿也有 有限的葡萄糖氧化(GOx)能力，这可能会将碳重新定向到GPR。我们在IUGR上发表的数据 胎儿支持FOXO1增加PCK1以增加葡萄糖产生，而PDK4增加以限制葡萄糖产生的机制 葡萄糖氧化。重要的是，PCK1和PDK4的表达与胎儿pO2呈负相关 说明低氧是GPR和GOX共同的调节因子。我们的目标是了解由低氧引起的 胎儿探地雷达早期激活的机制。我们假设胎儿缺氧会将FOXO1锁定为 活跃的核国家。此事件产生增加的PCK1，这增加了GPR，并增加了PDK4，这 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血氧分压来选择性地测试妊娠晚期低氧对胎儿肝脏的影响 从0.8-0.9孕期降至11-14毫米汞柱，这与年龄匹配的IUGR胎儿的胎儿氧分压相似。目标1将 确定胎儿缺氧在GPR升高和GOX降低的发展中的作用，并定义新的 调节胎儿代谢适应的分子机制。我会测量葡萄糖摄取量， 利用代谢示踪剂研究活体胎儿的利用、生产和氧化速率。在胎儿的肝脏里，我会 测量FOXO1信号通路，并期望确定低氧诱导FOXO1激活增加 PCK1和PDK4。胎儿肝脏代谢组的协调变化将被确定为支持增加 探地雷达用碳基板。目标2将确定胎儿肝细胞对GPR和GOX的底物偏好 由缺氧产生的。我将测量原代胎儿肝细胞的耗氧率，以确定 氨基酸在低氧时优先被氧化，以补偿GOx的下降。我会问你是怎么 低氧诱导的FOXO1信号通过选择性诱导和抑制GPR和GOX来协调GPR和GOX 狐狸1号。预期结果：胎儿缺氧将激活GPR并通过FOXO1特异性限制GOX 机械装置。影响：我将定义胎儿对低氧的代谢和分子适应，这是 了解低氧如何促进胎肝中GPR的早期激活，从而建立起与 在以后的生活中患上2型糖尿病。伴随这些研究目标的新陈代谢训练计划将 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，以促进我作为胎儿新陈代谢研究人员的独立性。

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.