IL-6 AND HEPATIC DYSFUNCTION IN SEPSIS

IL-6 与脓毒症中的肝功能障碍

• 批准号: 6636346
• 负责人: CLIFFORD Scott DEUTSCHMAN
• 金额: $ 25.36万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2005-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6636346
• 关键词: blood toxicology; cholanate compound; cholestasis; gel mobility shift assay; gene expression; genetic transcription; interleukin 6; laboratory mouse; liver cells; liver disorder; liver function; membrane transport proteins; multiple organ failure; nuclear runoff assay; nucleoproteins; protein structure function; transcription factor; transfection /expression vector; western blottings

DESCRIPTION ( Applicant's abstract.) Sepsis and the related Systemic Inflammatory Response Syndrome (SIRS) and Multiple Organ Dysfunction Syndrome (MODS) are important causes of death and disability in surgical or injured patients, although the exact cause of death is often obscure. These disorders are complex, involve a number of molecular mediators and effect most organs. Little is understood, however, about the manner in which organ dysfunction develops in these diseases. One important organ that is damaged in sepsis/SIRS/MODS is the lever. Intra-abdominal fecal contamination causes SIRS/MODS-like abnormalities in the liver of rodents. In this study we will examine one proposed mechanism that we believe contributes to the development of liver dysfunction in sepsis /SIRS/MODS. We have shown that intra-abdominal fecal contamination causes an early down regulation of transcription in this organ. This change affects many genes, including some encoding molecules that 1) transfer bile acids out of liver cells and into the biliary system and 2) allow liver cells to burn fat. We propose that the inflammatory cytokine IL-6 mediates some aspects of decreased gene expression, leading to liver cells that cannot excrete bile salts or burn fat. A build-up of bile salts and fat in liver cells "poisons" them so that they die. When enough liver cells die, liver dysfunction develops. The role played by IL-6 in this proposed mechanism of hepatic dysfunction will be studied in the setting of normal IL-6 levels, IL-6 absence, IL-6 excess and IL-6 repletion after depletion. Several specific measures will be studied. These include 1) transcription of the bile acid transporters Ntcp and Mrp2 and the rate-limiting enzyme in fat oxidation, CPTII, to be determined using transcription elongation analysis, 2) activation of two hepatic nuclear proteins, C/EBPalpha and HNF-1alpha, that modulate transcription of Ntcp, Mrp2 and CPTII and 3) the development of cholestasis (bile trapping in cells) and steatosis (fat trapping in cells) as indicated by microscopic examination of fixed liver sections. In addition, we will mimic IL-6 levels in sepsis in normal mice by 1) administering intravenous IL-6 and 2) injecting a virus that is taken up by the liver and produces high intrahepatic levels of IL-6. We will then study transcription, transcription factor activation, cholestasis and steatosis. These studies should provide key information on the role played by an important inflammatory mediator, IL-6, in the complex series of events that results in the hepatic dysfunction of SIRS/MODS.

描述(申请人的摘要。)脓毒症及其相关的全身性 炎症反应综合征(SIRS)与多器官功能障碍 综合征(MODS)是外科或外科手术中死亡和致残的重要原因。 受伤的患者，尽管确切的死因通常不清楚。这些 疾病是复杂的，涉及许多分子介质，影响最大 器官。然而，人们对器官以何种方式 在这些疾病中会出现功能障碍。一个重要的器官在 败血症/全身炎症反应综合征/多器官功能障碍综合征是杠杆。腹内粪便污染致病原因 啮齿动物肝脏SIRS/MODS样异常。在这项研究中，我们将 研究一个我们认为有助于发展的拟议机制 脓毒症/全身炎症反应综合征/多器官功能障碍综合征的肝功能障碍。我们已经证明了腹内 粪便污染导致早期转录下调 管风琴。这种变化影响了许多基因，包括一些编码分子 1)将胆汁酸从肝细胞转移到胆道系统；2) 让肝细胞燃烧脂肪。我们认为炎性细胞因子IL-6 介导基因表达下降的某些方面，导致肝细胞 不能排泄胆盐或燃烧脂肪。体内胆盐和脂肪的堆积 肝细胞“毒害”它们，使它们死亡。当足够多的肝细胞死亡时，肝脏 就会出现功能障碍。IL-6在这一机制中所起的作用 将在IL-6水平正常的情况下研究肝功能障碍，IL-6 缺勤、IL-6过剩和耗竭后IL-6再耗竭。几个具体的 我们会研究有关措施。其中包括1)胆汁酸的转录 转运蛋白Ntcp和MRp2以及脂肪氧化中的限速酶， CPTII，通过转录延伸分析来确定，2)激活 两种肝脏核蛋白，C/EBPalpha和HNF-1α，调节 Ntcp、MRP2和CPTII的转录及3)胆汁淤积的发生 (胆汁滞留在细胞内)和脂肪变性(脂肪滞留在细胞内)，如 固定肝脏切片的显微镜检查。此外，我们还将模仿 正常小鼠脓毒症中IL-6水平的变化：1)静脉注射IL-6和 2)注射一种被肝脏摄取的病毒，并产生高水平的 肝内IL-6水平。然后我们将学习转录，转录 因子活化、胆汁淤积和脂肪变性。这些研究应该提供关键 关于重要的炎症介质IL-6在 导致肝功能障碍的一系列复杂事件 先生/国防部。