Kupffer cell activation and hepatic injury after ethanol and burn

乙醇和烧伤后库普弗细胞活化和肝损伤

• 批准号: 8738266
• 负责人: Michael M Chen
• 金额: $ 3.27万
• 依托单位: LOYOLA UNIVERSITY CHICAGO
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2017-09-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8738266
• 关键词: Abbreviations; Ablation; Acute-Phase Proteins; Alanine Transaminase; Alcoholic Intoxication; Alcohols; Alkaline Phosphatase; Animal Model; Aspartate Transaminase; Attenuated; Bacterial Translocation; Biological Markers; Blood; Body Surface Area; Burn injury; CCL2 gene; Caring; Cytokine Signaling; Dichloromethylene Diphosphonate; Endotoxins; Ethanol; Ethanol Metabolism; Ethanol toxicity; Gamma-glutamyl transferase; Hematoxylin and Eosin Staining Method; Hepatic; Hepatocellular Damage; Hormonal; Hospitalization; Individual; Infection; Inflammatory; Injury; Interleukin-1; Interleukin-10; Interleukin-6; Intestines; Knowledge; Kupffer Cells; Laboratories; Length of Stay; Lipopolysaccharides; Liposomes; Liver; Liver diseases; MYLK gene; Measurement; Measures; Membrane; Messenger RNA; Metabolic; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Modeling; Monocyte Chemoattractant Protein-1; Morbidity - disease rate; Mus; Myosin Light Chain Kinase; Operative Surgical Procedures; Organ; Orosomucoid; Outcome; Patients; Permeability; Phosphorylation; Pneumonia; Polymerase Chain Reaction; Population; Positioning Attribute; Production; Protein Isoforms; Proteins; Relative (related person); Reporting; Research; Risk; Risk Factors; Role; Serum; Serum Markers; Signal Transduction; Signal Transduction Pathway; Signaling Protein; Site; Source; TNF gene; Testing; Therapeutic; Therapeutic Intervention; Time; Tissues; Toll-like receptors; Transforming Growth Factors; Trauma; Tumor Necrosis Factor-alpha; United States; alcohol exposure; clinically relevant; cytokine; feeding; improved; in vivo; indexing; injured; kinase inhibitor; liver function; liver injury; mortality; mouse model; new therapeutic target; non-alcoholic fatty liver; oil red O; outcome forecast; patient population; public health relevance; research study; response; toll-like receptor 4

DESCRIPTION (provided by applicant): Over half of the U.S. population consumes alcohol and intoxication has been implicated in nearly all forms of traumatic injury, including burns. Alcohol exposure prior to burn escalates morbidity and mortality, though the mechanism of this interaction is unknown. As a central organ sensitive to cytokine signaling and alcohol metabolism, the liver is positioned to be enmeshed in this injurious response. The studies proposed herein intend to elucidate the role of the liver in the common setting of burn injury preceded by ethanol exposure and determine the cellular mechanisms involved so that targeted approaches to therapeutic intervention can be identified. Of the cytokines elevated when alcohol exposure precedes a burn, IL-6 has been correlated with increased mortality risk in trauma patients. Within the liver, Kupffer cells are a source of IL-6 production and function to orchestrate hepatic responses to products in the blood, including ethanol and endotoxin. Ethanol sensitizes Kupffer cells to gut-derived endotoxin through a variety of mechanisms including activation of the Toll-like receptor 4 (TLR4) signaling proteins such as mitogen activated protein kinase (MAPK). Additionally, both ethanol and burn injury have independently been shown to increase intestinal permeability and gut- derived endotoxin which signals through TLR4 on Kupffer cells and causes their activation and subsequent IL- 6 production. From these pieces of evidence, we hypothesize that alcohol intoxication exacerbates the hepatic response to burn injury through a feed forward loop involving Kupffer cell sensitization to gut- derived LPS, increased intestinal permeability and hepatic IL-6 production. To test this hypothesis, we will use our well-established mouse model of alcohol exposure and burn injury to (Aim1) determine the effects of episodic binge ethanol on the post burn hepatic response. This will be investigated through multiple measures of hepatocellular damage, indices of liver function, and pro-inflammatory cytokine production. We will then (Aim2) determine if depletion of Kupffer cells or restoring gut barrier function attenuates hepatic damage and IL-6 production after ethanol intoxication and burn injury. This will be accomplished by administering clodronate liposomes in vivo to deplete Kupffer cells and administering membrane-permeant inhibitor of kinase (PIK) in vivo to reduce intestinal permeability. Finally, in our third aim we will (Aim3) identify the speciic MAPK isoforms in Kupffer cells responsible for TLR4-induced production of IL-6 after episodic binge ethanol and burn injury. Taken together, these studies will expand on our knowledge of how ethanol deranges the hepatic response to burn, and by identifying the mechanisms of this response, may reveal therapeutic strategies to alleviate the excessive morbidity and mortality in this patient population.

描述（由申请人提供）：超过一半的美国人口饮酒，几乎所有形式的外伤都与中毒有关，包括烧伤。烧伤前接触酒精会增加发病率和死亡率，但这种相互作用的机制尚不清楚。作为对细胞因子信号传导和酒精代谢敏感的中央器官，肝脏很容易卷入这种有害反应。本文提出的研究旨在阐明肝脏在乙醇暴露之前烧伤的常见情况中的作用，并确定所涉及的细胞机制，以便可以确定有针对性的治疗干预方法。在烧伤前接触酒精时升高的细胞因子中，IL-6 与创伤患者死亡风险增加相关。在肝脏内，库普弗细胞是 IL-6 产生的来源，其功能是协调肝脏对血液中的产物（包括乙醇和内毒素）的反应。乙醇通过多种机制使 Kupffer 细胞对肠源性内毒素敏感，包括激活 Toll 样受体 4 (TLR4) 信号蛋白，例如丝裂原激活蛋白激酶 (MAPK)。此外，乙醇和烧伤均已被独立证明会增加肠道通透性和肠源性内毒素，内毒素通过 Kupffer 细胞上的 TLR4 发出信号，并导致其激活和随后的 IL-6 产生。根据这些证据，我们假设酒精中毒通过前馈循环加剧了肝脏对烧伤的反应，该循环涉及库普弗细胞对肠源性 LPS 的敏感性、肠道通透性增加和肝脏 IL-6 的产生。为了检验这一假设，我们将使用我们完善的酒精暴露和烧伤小鼠模型来（目标1）确定间歇性暴饮乙醇对烧伤后肝脏反应的影响。这将通过肝细胞损伤、肝功能指数和促炎细胞因子产生的多种测量来进行研究。然后（目标 2）确定枯否细胞的消耗或恢复肠道屏障功能是否会减轻乙醇中毒和烧伤后的肝损伤和 IL-6 的产生。这将通过在体内施用氯膦酸盐脂质体以消耗库普弗细胞并在体内施用膜渗透性激酶抑制剂（PIK）以降低肠道通透性来实现。最后，在我们的第三个目标中，我们将 (Aim3) 鉴定 Kupffer 细胞中负责 TLR4 诱导偶发性酗酒和烧伤后产生 IL-6 的特定 MAPK 亚型。总而言之，这些研究将扩展我们对乙醇如何扰乱肝脏对烧伤反应的认识，并通过确定这种反应的机制，可能揭示减轻该患者群体过度发病率和死亡率的治疗策略。