LPS INDUCED ENDOTHELIAL CELL ACTIVATION AND APOPTOSIS

LPS 诱导内皮细胞活化和凋亡

• 批准号: 6519351
• 负责人: ROBERT K WINN
• 金额: $ 23.41万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6519351
• 关键词: apoptosis; bacterial proteins; binding proteins; blood toxicology; cellular immunity; cysteine endopeptidases; cytokine receptors; human tissue; immunocytochemistry; inflammation; interleukin 1; ischemia; laboratory mouse; leukocyte activation /transformation; leukocyte adhesion molecules; lipopolysaccharides; macrophage; monocyte; nuclear factor kappa beta; protein structure function; reperfusion; tissue /cell culture; tumor necrosis factor alpha; vascular endothelium; western blottings

Septic shock is a potentially lethal consequence of gram negative and positive bacterial infection and is a significant complication in victims of traumatic injury. There are multiple bacterial products implicated as pathogenic molecules including bacterial lipoproteins, lipopolysaccharide, (LPS), lipoteichoic acid, peptidoglycans, cell wall products, etc. Sepsis in experimental animals was shown to activate the intrinsic cell "suicide" program leading to apoptosis in multiple cell types. Insights into the molecular basis of cellular activation/apoptosis in response to sepsis are under intense investigation in the hope of finding new approaches to therapy. Signaling by bacterial products occurs through the recently described Toll-like receptors (TLR) on the surface of cells. Intracellular pathways leading to NFkappaB activation proceed along similar pathways for TLR-2 and TLR-4 (the two receptors shown to respond to bacterial products). However, apoptosis pathways have received less attention. The investigators will examine sepsis-induced apoptosis and a novel activation pathway in vitro as well as the effect of gene alterations that lead to decreased apoptosis in monocytes, lymphocytes and endothelial cells in vivo. They have recently shown that the apoptotic pathway following stimulation with LPS proceeds through FADD dependent signaling and that blockade of NFkappaB does not sensitize endothelial cells to death. These observation lead to questions regarding the death pathway and intrinsic cyto-protective pathways. Since considerable apoptosis occurs in LPS resistant (TLR-4 deficient) mice during sepsis, we also speculate that TLR-2 provides both activation signals and death signals in TLR-4 deficient mice. Also, they have observed two pathways leading to endothelial cell activation. First, mice lacking functional Fas (lpr) or FasL (gld) have reduced responses to LPS, and they postulate that the Fas-FasL system is pro-imflammatory. Second, a specific caspase-8 inhibitor reduces LPS-induced VCAM-1 expression. They postulate that this protease also signals for endothelial cell activation. The specific aims of this project are: 1) To determine the role of MyD88, Il-1 receptor- associated kinase and TNF receptor- associated factor-6 in sepsis-induced apoptosis of monocytes/macrophages and endothelial cells; 2) To determine the contribution of Fas-FasL and other molecules in that apoptosis pathway in LPS-induced inflammatory response of endothelial cells; and 3) To examine the effects of apoptotic gene alterations in monocytes, lymphocytes or endothelial in survival following induction of sepsis in mice.

败血性休克是革兰氏阴性的潜在致命后果 和阳性细菌感染，是受害者的重要并发症 创伤性损伤。有多种细菌产品涉及 病原分子，包括细菌脂蛋白，脂多糖， （LPS），脂肪酸，肽聚糖，细胞壁产品等。 显示实验动物可以激活固有细胞“自杀”程序 导致多种细胞类型的凋亡。洞察分子基础 败血症响应的细胞激活/凋亡的强度 调查希望找到新的治疗方法。信号传递 细菌产物通过最近描述的Toll样受体发生 （TLR）在细胞表面。导致NFKappab的细胞内途径 激活沿着TLR-2和TLR-4的相似途径进行（两个 被证明对细菌产物反应的受体）。但是，凋亡途径 受到更少的关注。调查人员将检查败血症引起的 凋亡和一种新型的体外激活途径以及基因的作用 导致单核细胞，淋巴细胞和 体内内皮细胞。他们最近表明凋亡途径 在用LPS进行刺激后，通过FADD依赖信号传导和 NFKappab的封锁不会使内皮细胞致死。这些 观察导致有关死亡途径和内在的问题 细胞保护途径。由于LPS抗性发生相当大的凋亡 （TLR-4缺陷）小鼠败血症期间，我们还推测TLR-2提供 TLR-4缺陷小鼠中的激活信号和死亡信号。另外，他们 已经观察到导致内皮细胞激活的两种途径。首先，老鼠 缺乏功能性FA（LPR）或FASL（GLD）的响应减少，并且 他们假设FAS-FASL系统是促炎症的。第二，特定于 caspase-8抑制剂降低了LPS诱导的VCAM-1表达。他们假设 该蛋白酶还信号用于内皮细胞激活。具体目标 该项目的内容是：1）确定MyD88，IL-1受体的作用 相关的激酶和TNF受体与败血症诱导的因子-6 单核细胞/巨噬细胞和内皮细胞的凋亡； 2）确定 FAS-FASL和其他分子在该凋亡途径中的贡献 LPS诱导的内皮细胞的炎症反应； 3）检查 单核细胞，淋巴细胞或内皮细胞中凋亡基因改变的作用 在小鼠诱导败血症后的生存中。