IGFBP-1 hyperphosphorylation in IUGR: Role of mTOR and CK2

IUGR 中 IGFBP-1 过度磷酸化：mTOR 和 CK2 的作用

基本信息

批准号：
8611584
负责人：
Madhulika Gupta
金额：
$ 4.24万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-01 至 2014-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8611584
关键词：
Adult Affect Affinity Amino Acids Amniotic Fluid Binding Binding Proteins Biological Availability Blood Cardiovascular Diseases Cells Childhood Complex Critical Pathways Data Development Diabetes Mellitus Disease Enzyme-Linked Immunosorbent Assay Essential Amino Acids Fetal Development Fetal Growth Fetal Growth Retardation Fetal Liver Fetus Figs - dietary Functional disorder Gene Silencing Growth Growth Factor Hepatocyte Human Hypoxemia Immunoblotting In Vitro Injury Insulin-Like Growth Factor I Insulin-Like Growth-Factor Binding Protein 1 Leucine Life Link Liver Mediating Metabolism Modeling Molecular Morbidity - disease rate Mus Nutrient Obesity Papio Perinatal Phosphorylation Protein Kinase Regulation Research Risk Role Sampling Serum Signal Transduction Sirolimus Site Small Interfering RNA TSC2 gene Testing Tissues Umbilical Blood Umbilical Cord Blood Western Blotting Work base casein kinase II cell growth cell growth regulation deprivation design fetal fetus cell human FRAP1 protein in vivo inhibitor/antagonist innovation mTOR protein maternal nutrient restriction mortality nonhuman primate novel public health relevance response

项目摘要

Intrauterine growth restriction (IUGR) increases the risk for perinatal complications and predisposes for adult disease. Insulin-like growth factor I (IGF-I) is a key regulator of fetal growth, and IGF-I bioavailability is modulated by binding to IGF binding protein-1 (IGFBP-1). We and others have provided evidence that phosphorylation of IGFBP-1 markedly increases its affinity to bind IGF-I and that IGFBP-1 hyperphosphorylation may constitute an important mechanism by which growth is reduced in IUGR. However, the molecular mechanisms causing IGFBP-1 phosphorylation in IUGR are largely unknown. The central hypothesis in this mechanistic proposal is that inhibition of mTOR signaling and activation of protein kinase CK2 in the fetal liver constitutes a key molecular link between nutrient deprivation and increased IGFBP-1 secretion and phosphorylation in vitro and in IUGR in vivo. Our hypothesis has been formulated based on our compelling preliminary data including the demonstration that (1) mTOR inhibition induces marked IGFBP-1 phosphorylation and silencing of protein kinase CK2 abolishes IGFBP-1 hyperphosphorylation induced by mTOR inhibition in HepG2 cells and (2) mTOR activity is decreased whereas CK2 expression and IGFBP-1 phosphorylation are increased in the liver of IUGR baboons. To test our hypothesis, we will study HepG2 cells, primary fetal hepatocytes from baboons, and blood and liver tissue of control and IUGR baboon fetuses in two specific aims: In Aim 1 we will use gene silencing approaches and pharmacological inhibitors in HepG2 cells and fetal baboon primary hepatocytes to mechanistically link mTOR signalling to regulation of protein kinase CK2 and IGFBP-1 phosphorylation. In addition, we will test the hypothesis that the increased IGFBP-1 phosphorylation due to amino acid deprivation is mediated by inhibition of mTOR and activation of CK2. In Aim 2 we will use a well-established baboon model of IUGR involving maternal nutrient restriction. We will determine the activity of mTOR and CK2, IGFBP-1 expression and phosphorylation in fetal liver samples and IGFBP-1 serum concentrations and phosphorylation in control and IUGR baboon fetuses. Significance: This work has the potential to identify a novel molecular mechanism underlying the development of IUGR. Furthermore, we will utilize a highly relevant non-human primate model that provides unique access to fetal samples not available through human studies. Innovation: This work will provide an innovative mechanistic link between mTOR and IGF-I signaling, two critical pathways in the regulation of cell growth. The combination of mechanistic approaches in cultured HepG2 and primary fetal baboon hepatocytes with studies of liver tissue from a baboon IUGR model is translational and innovative.

宫内生长受限（IUGR）会增加围产期并发症的风险，并容易导致成人疾病。胰岛素样生长因子 I (IGF-I) 是胎儿生长的关键调节因子，IGF-I 的生物利用度通过与 IGF 结合蛋白-1 (IGFBP-1) 结合进行调节。我们和其他人提供的证据表明 IGFBP-1 的磷酸化显着增加其与 IGF-I 结合的亲和力，并且 IGFBP-1 过度磷酸化可能是 IUGR 生长减缓的重要机制。然而，引起 IUGR 中 IGFBP-1 磷酸化的分子机制在很大程度上尚不清楚。中央该机制提议中的假设是 mTOR 信号传导的抑制和蛋白激酶的激活胎儿肝脏中的 CK2 构成营养缺乏和 IGFBP-1 增加之间的关键分子联系体外和体内 IUGR 的分泌和磷酸化。我们的假设是根据我们的令人信服的初步数据，包括证明 (1) mTOR 抑制诱导显着的 IGFBP-1 蛋白激酶 CK2 的磷酸化和沉默消除了 IGFBP-1 诱导的过度磷酸化 HepG2 细胞中的 mTOR 抑制和 (2) mTOR 活性降低，而 CK2 表达和 IGFBP-1 IUGR 狒狒肝脏中的磷酸化增加。为了检验我们的假设，我们将研究 HepG2 细胞，来自狒狒的原代胎儿肝细胞，以及两个对照和IUGR狒狒胎儿的血液和肝组织具体目标：在目标 1 中，我们将在 HepG2 细胞中使用基因沉默方法和药物抑制剂和胎儿狒狒原代肝细胞在机制上将 mTOR 信号传导与蛋白激酶的调节联系起来 CK2 和 IGFBP-1 磷酸化。此外，我们将检验 IGFBP-1 增加的假设氨基酸剥夺导致的磷酸化是通过抑制 mTOR 和激活 CK2 介导的。瞄准 2 我们将使用一个完善的 IUGR 狒狒模型，涉及母体营养限制。我们将测定胎儿肝脏样本中 mTOR 和 CK2 的活性、IGFBP-1 表达和磷酸化，以及对照和 IUGR 狒狒胎儿中 IGFBP-1 血清浓度和磷酸化。意义：这个这项工作有可能确定 IUGR 发展的新分子机制。此外，我们将利用高度相关的非人类灵长类动物模型，为胎儿提供独特的途径无法通过人体研究获得样本。创新：这项工作将提供创新的机制链接 mTOR 和 IGF-I 信号传导之间的关系，这是细胞生长调节的两条关键途径。的组合通过肝组织研究培养的 HepG2 和原代胎儿狒狒肝细胞的机制方法来自狒狒的 IUGR 模型具有转化性和创新性。