Regulation of Protein Synthesis in Neonatal Sepsis

新生儿败血症中蛋白质合成的调节

• 批准号: 6923396
• 负责人: RENAN A ORELLANA
• 金额: $ 12.29万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6923396
• 关键词: aminoacid metabolism; blood toxicology; developmental nutrition; dietary aminoacid; endotoxins; hormone regulation /control mechanism; insulin; muscle metabolism; muscle proteins; newborn animals; nuclear factor kappa beta; nutrition related tag; phosphorylation; protein biosynthesis; proteolysis; septicemia; serine threonine protein kinase; swine; translation factor

DESCRIPTION (provided by applicant): The susceptibility of the neonate for nutritional depletion during illness, and its opposed metabolic ability to utilize nutrients efficiently for growth offers a novel paradigm to evaluate nutrient-hormonal interactions during sepsis. Our long-term objectives are to identify the fundamental mechanisms that regulate amino acid use, including the interaction of hormones, nutrients, and development, in inflammatory conditions such as sepsis. In this proposal, we intend to analyze the pathways that regulate amino acid metabolism in septic neonates. In Aim 1, we hypothesize that raising amino acids in endotoxemic neonates enhances muscle protein synthesis rates. Thus, amino acid dose response studies will be performed in endotoxin (LPS) infused 7- and 26-day-old pigs by using hormone-substrate clamp techniques and in vivo measurement of protein synthesis with isotopic tracer methods. In Aim 2, we wish to determine whether amino acids influence muscle protein synthesis in LPS-infused neonates by affecting activation of translation initiation factors involved in the binding of mRNA, but not met-tRNAi, to the 40S ribosomal complex. Consequently, we will measure in muscle eukaryotic initiation factor (elF) 2B activity, the phosphorylation of eIF4E, 4E-BP1, p70S6 kinase and protein kinase B (PKB), the association of eIF4E with eIF4G and 4E-BP1, and the activation of NFkappaB signaling. In Aim 3, we wish to determine whether muscle proteolysis is enhanced by sepsis in neonates and whether the rate of proteolysis can be suppressed by administration of insulin. Therefore, LPS-infused 7- and 26-day-old pigs subjected to hormone-substrate clamps will be examined using a stable isotopic tracer/mass transorgan balance technique to quantify protein degradation in the hindlimb in the presence of different concentrations of insulin. Knowledge of the nutrient-hormone interface during a critical illness and their developmental distinctiveness can help characterize and optimize the medical management towards recovery and reestablishment of adequate growth after infants and children have been acutely ill.

描述（由申请人提供）： 新生儿在疾病期间对营养耗尽的敏感性，以及其有效利用营养物质促进生长的相对代谢能力，为评估脓毒症期间营养-激素相互作用提供了一个新的范例。我们的长期目标是确定调节氨基酸使用的基本机制，包括脓毒症等炎症条件下激素、营养素和发育的相互作用。在本提案中，我们打算分析调节脓毒症新生儿氨基酸代谢的途径。在目标 1 中，我们假设增加内毒素血症新生儿的氨基酸水平可提高肌肉蛋白合成率。 因此，将通过使用激素底物钳技术和同位素示踪方法体内测量蛋白质合成，在注射内毒素（LPS）的 7 日龄和 26 日龄猪中进行氨基酸剂量反应研究。在目标 2 中，我们希望确定氨基酸是否影响注入 LPS 的肌肉蛋白质合成 通过影响参与 mRNA（但不包括 met-tRNAi）与 40S 核糖体复合物结合的翻译起始因子的激活来对新生儿产生影响。因此，我们将测量肌肉真核起始因子 (elF) 2B 活性、eIF4E、4E-BP1、p70S6 激酶和蛋白激酶 B (PKB) 的磷酸化、eIF4E 与 eIF4G 和 4E-BP1 的关联以及 NFkappaB 信号传导的激活。在目标 3 中，我们希望确定新生儿脓毒症是否会增强肌肉蛋白水解作用，以及胰岛素的施用是否可以抑制蛋白水解速率。因此，将使用稳定同位素示踪剂/质量跨器官平衡技术对注射 LPS 的 7 日龄和 26 日龄猪进行激素底物钳检查，以量化不同浓度胰岛素存在下后肢的蛋白质降解。了解危重疾病期间的营养-激素界面及其发育独特性可以帮助描述和优化医疗管理，以实现婴儿和儿童患重病后的恢复和重新建立适当的生长。