Mechanisms Of Placental Nutrient Sensing In The Baboon

母体营养限制与胎儿生长发育和成体发育的关系 疾病仍有待完全确定。我们已经提出胎盘的功能是营养传感器， 调节胎盘营养转运蛋白，从而调节胎儿生长，以响应 将营养物质输送到胎盘的物质供应线。我们将检验抑制的中心假设， 胎盘胰岛素/IGF-I、瘦素和mTOR信号传导构成母体与胎盘胰岛素/IGF-I、瘦素和mTOR信号传导之间的关键分子联系。 胎盘营养下调导致的营养限制、胎儿生长和胎儿编程降低 转运蛋白，这限制了胎儿的氨基酸和甲基供体的供应。我们将研究物质营养 妊娠狒狒中的限制（IVINR，-^30%营养摄入）。对照组和MNR狒狒的胎盘将 在两个胎龄（GD 140和180）进行研究。在目标1中，我们将确定MNR对 物质代谢、胎盘信号传导和蛋白质合成。我们会测量母体激素， 脂肪因子和营养水平以及胎盘胰岛素/IGpTl、瘦素、mTOR、AMPK、GCN 2和GSK 3信号传导。 特定蛋白质的合成将通过使用稳定同位素标记的定量蛋白质组学来确定 用培养物中的氨基酸（SILAC）、二甲基标记和LC-MS/MS进行测定。 将确定营养物和甲基供体的胎盘转运和胎血清浓度。的 葡萄糖、氨基酸和甲基供体（叶酸、维生素E）的转运体的活性和蛋白质表达 B12）将在合体滋养层质膜中测定。氨基在体内经胎盘转运 将使用稳定同位素测量酸。在目标1和目标2中，我们将使用高吞吐量发现 方法（下一代测序）来发现额外的和新型的胎盘信号通路， 由MNR调节的转运蛋白。在目标3中，我们将确定亮氨酸和胎盘mTOR信号传导的作用。 MNR与胎盘营养转运减少和胎儿生长减慢有关。MNR动物将 从GD 30开始补充亮氨酸。胎盘mTOR信号的活性和表达， 葡萄糖、氨基酸和甲基供体的转运蛋白，以及胎儿营养水平和生长将被 测定重要性：在美国，营养不良是一个严重的公共卫生问题， 国际吧这项工作将探索MNR与胎盘功能改变的分子机制， 在非人类灵长类动物中胎儿生长减少。创新：胎盘营养感应假说是 概念新颖，挑战了胎盘功能如何调节的传统观点。 相关性（参见说明）： 怀孕期间的产妇营养不良仍然是一个令人生畏的问题，全世界有5000多万 美国人生活在经历粮食不安全或饥饿的家庭中。我们将探索 在非人类灵长类动物中，母体营养限制改变了胎盘功能并降低了胎儿生长。 预计这一知识将提高我们对共同的根本原因的理解。 妊娠并发症，并可能允许开发新的治疗策略。

The mechanisms linking matemal nutrient restriction to reduced fetal growth and programming of adult disease remain to be fully established. We have proposed that the placenta functions as a nutrient sensor, regulating placental nutrient transporters, and therefore fetal growth, in response to changes in the ability of the matemal supply line to deliver nutrients to the placenta. We will test the central hypothesis that inhibition of placental insulin/IGF-l, leptin and mTOR signaling constitute a key molecular link between maternal nutrient restriction, reduced fetal growth and fetal programming by downrregulatlon of placental nutrient transporters, which limits fetal supply of amino acids and methyl donors. We will study matemal nutrient restriction (IVINR, -^30% nutrient intake) in pregnant baboons. Placentas from control and MNR baboons will be studied at two gestational ages (GD 140 and 180). In Aim 1, we will determine the effect of MNR on matemal metabolism, placental signaling and protein synthesis. We will measure maternal hormone, adipokine and nutrient levels and placental insulin/IGpTl, leptin, mTOR, AMPK, GCN2, and GSK3 signaling. Synthesiis of specific proteins will be determined by quantitative proteomics using Stable Isotope Labeling with Amino acids in Culture (SILAC), dimethyl labeling and LC-MS/MS. In Aim 2 the impact of MNR on placental transport and fetal serum concentrations of nuti-ients and methyl donors will be established. The activity and protein expression of transporters for glucose, amino acids and methyl donors (folate, vitamin B12) will be determined in syncytiotrophoblast plasma membranes. In vivo transplacental transport of amino acids will be measured using stable isotopes. In both Aim 1 and 2, we will use high throughput discovery approaches (Next Gen sequencing) to discover additional and novel placental signaling pathways and transporters regulated by MNR. In Aim 3 we will determine the role of leucine and placental mTOR signaling in linking MNR to decreased placental nutrient transport and reduced fetal growth. MNR animals will be Supplemented with leucine from GD 30. The activity and expression of placental mTOR signaling and transporters for glucose, amino acids and metiiyl donors, and fetal nutrient levels and growth will be determined. Significance: Matemal under nutrition is a serious public health problem in the US and worldwide. This work will explore the molecular mechanisms linking MNR to altered placental function and reduced fetal growth in the non-human primate. Innovation: The placental nutrient sensing hypothesis is conceptually novel and challenges the traditional view of how placental function is regulated. RELEVANCE (See instructions): Maternal under nutiition during pregnancy remains a daunting problem worldwide and more than 50 million Americans live in households experiencing food insecurity or hunger. We will explore the mechanisms linking matemal nutrient restriction to altered placental function and reduced fetal growth in the non^human primate. It is expected that this knowledge will improve our understanding of the causes underlying common pregnancy complications and may allow the development of novel treatment strategies.