Mechanisms of Lung Inflammation Following Discrete Hepatic Injury

离散性肝损伤后肺部炎症的机制

• 批准号: 6577690
• 负责人: WILLIAM C CHAPMAN
• 金额: $ 27.66万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6577690
• 关键词: cryosurgery; cytokine; cytokine receptors; eicosanoids; enzyme linked immunosorbent assay; gene expression; gene targeting; genetically modified animals; inflammation; interleukin 1; laboratory mouse; liver disorder; lung injury; northern blottings; nuclear factor kappa beta; pathologic process; postoperative complications; prostacyclins; prostaglandin E; prostaglandin endoperoxide synthase; prostaglandin receptor; transcription factor; transfection; tumor necrosis factor alpha; western blottings

There is increasing evidence that injury to the liver can precipitate or exaggerate lung injury. For example, when hepatic dysfunction accompanies acute lung injury in patients with the Systemic Inflammatory Response Syndrom (SIRS), mortality and morbidity are high. Cytokines which are produced in both the liver and the lungs, including tumor necrosis factor alpha (TNF-alpha) and interleukin (IL- 1), are implicated in the pathogenesis of SIRS and animal experiments have demonstrated them capable of precipitating acute lung injury. Increased expression of the genes encoding these cytokines involves activation of the transcription factor nuclear factor kappa B (NF-kappaB) and such activation is well-documented in several inflammatory states. Hepatic cryoablation, a recently introduced non-resectional surgical technique for eliminating primary and metastatic liver tumors, is associated with acute lung injury when more than 30-35% of the liver is ablated but mechanisms of this response remain undefined. We have shown that the direct and selective liver injury produced by cryoablation in experimental animals causes an early activation of NF-kappaB in the liver, followed by TNF-alpha release from the liver and then NF-kappaB activation in the lungs with histologic findings similar to those seen in other conditions of neutrophilic lung injury; none of these events follows hepatic resection. The specific aims of this project are: 1) To determine whether altering NF-kappaB activation in the liver affects the response to cryoablation induced lung injury. NF-kappaB activation will be specifically modulated by expressing transgenes in the liver which induce or inhibit NF-kappaB activity. We will also utilize the cell permeable cSN50 peptide, which contains the nuclear localization signal sequence (NLS) derived from the p50-NF-kappaB1 subunit to inhibit NF-kappaB prior to and following direct liver injury. 2) To determine the role of the proximal cytokines, TNF-alpha and IL-1, in the response to hepatic cryoablation by comparing responses in mice deficient in TNF-alpha and IL-1, in the response to hepatic cryoablation by comparing responses in mice deficient in TNF-alpha, TNF-alpha receptor 1 and/or IL-1 receptor 1. Outcome variables will include neutrophilic lung inflammation, histologically defined lung injury, NF- kappaB activation, and serum and lung lavage cytokine and eicosanoid concentrations. 3) To determine the role of eicosanoids in the response to hepatic cryoablation by altering cyclooxygenase (COX) expression and/or activity in liver or lungs. In these studies we will define COX-2 expression in response to cryoablation in lung and liver and measure prostanoid products, determine the role of COX-2 in the cryoablation response by using COX-2 inhibitors and COX-2 knockout mice, and establish whether liver COX-2 expression is critical for modulating the cryoablation response by transplantation of wild type hepatocytes into COX-2 knockout mice and by delivering transgenes to express COX-2 in these animals. Results of these studies should enhance our understanding of the role of the liver in propagation in response to direct liver injury.

越来越多的证据表明，肝脏损伤会加速或加重肺损伤。例如，在全身炎症反应综合征(SIRS)患者中，当肝功能障碍伴急性肺损伤时，死亡率和发病率都很高。在肝脏和肺中产生的细胞因子，包括肿瘤坏死因子α(TNF-α)和白介素1(IL-1)，与SIRS的发病机制有关，动物实验证明它们能够加速急性肺损伤。编码这些细胞因子的基因的表达增加涉及到转录因子核因子kappaB(NF-kappaB)的激活，这种激活在几种炎症状态下都得到了很好的证明。肝脏冷冻消融术是最近推出的一种消除原发和转移性肝肿瘤的非切除外科技术，当超过30%-35%的肝脏被切除时，这种反应与急性肺损伤有关，但这种反应的机制尚不清楚。我们已经证明，冷冻消融产生的直接和选择性的肝损伤导致肝脏中核因子-kappaB的早期激活，随后肝脏释放肿瘤坏死因子-α，然后肺中核因子-kappaB被激活，组织学结果类似于其他情况下的中性粒细胞肺损伤；这些事件都不是肝脏切除后发生的。本项目的具体目的是：1)确定改变肝脏中核因子-kappaB的激活是否影响冷冻消融所致肺损伤的反应。核因子-kappaB的激活将通过在肝脏中表达诱导或抑制核因子-kappaB活性的转基因来特异性地调节。我们还将利用细胞通透性cSN50肽，它包含来自p50-NF-kappaB1亚单位的核定位信号序列(NLS)，在直接肝损伤之前和之后抑制NF-kappaB。2)通过比较肿瘤坏死因子-α、肿瘤坏死因子-α受体1和/或白介素1受体1缺陷小鼠的反应，以确定近端细胞因子--肿瘤坏死因子-α和白介素1在肝脏冷冻消融反应中的作用。结果变量将包括中性粒细胞肺炎症、组织学明确的肺损伤、核因子-kappaB激活、血清和肺灌洗液细胞因子和二十烷类化合物浓度。3)通过改变肝脏或肺组织环氧合酶(COX)的表达和/或活性，确定二十烷类化合物在肝脏冷冻消融反应中的作用。在这些研究中，我们将定义COX-2在肺和肝脏中的表达，并测量前列腺素产物，通过使用COX-2抑制剂和COX-2基因敲除小鼠来确定COX-2在冷冻消融反应中的作用，并通过将野生型肝细胞移植到COX-2基因敲除小鼠中以及通过在这些动物中传递转基因来表达COX-2来确定肝脏COX-2的表达是否在调节冷冻消融反应中起关键作用。这些研究的结果应该会加强我们对肝脏在直接肝损伤反应中的作用的理解。