Alterations In Pulmonary Immune Function And Host Resist

肺免疫功能和宿主抵抗力的改变

• 批准号: 7168264
• 负责人: Darryl C Zeldin
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7168264
• 关键词: allergens; disease /disorder model; endotoxins; environmental exposure; enzyme deficiency; enzyme linked immunosorbent assay; enzyme mechanism; flow cytometry; genetically modified animals; human subject; immune response; inflammation; influenza; laboratory mouse; leukotrienes; molecular pathology; prostaglandin endoperoxide synthase; prostaglandins; respiratory function

We are investigating the role of cyclooxygenases in the pulmonary response to environmental agents. At baseline, lung prostaglandin E2 levels are lower in COX-1 null mice compared to either wild type or COX-2 null mice, but there are no significant differences in basal lung function or in lung histopathology between the genotypes. Following allergen (ovalbumin) sensitization/exposure, lung inflammatory indices are significantly greater in COX-1 null and COX-2 null mice compared to wild type mice. Airways of allergic COX-1 null mice have increased numbers of eosinophils and increased numbers of CD3+/CD4+ lymphocytes (Th cells). Alveolar macrophages from allergic COX-1 null airways show biochemical and morphologic evidence of activation. Bronchoalveolar lavage fluid (BALF) from allergic COX-1 null mice contains significantly higher levels of the Th2 cytokines IL-4, IL-5 and IL-13, increased levels of LTB4 and the cysteinyl leukotrienes, and increased levels of the chemokines TARC and eotaxin. These changes in the COX-1 null mice are associated with increased BALF IgE levels and increased MUC5AC production/mucin secretion. Moreover, expression of the adhesion molecules VCAM-1 and ICAM-1 are increased in the lungs of both allergic COX-1 and allergic COX-2 null mice. Allergic COX-1 null mice have reduced lung compliance, increased allergen-induced bronchoconstriction and display hyperresponsiveness to inhaled methacholine. We have also examined the effects of disruption of COX genes on the pulmonary responses to other environmentally relevant agents including inhaled endotoxin (bacterial lipopolysaccharide, LPS), vanadium pentoxide, and influenza virus. Following LPS exposure, all mice exhibit increased bronchoconstriction and methacholine hyperresponsiveness; however, these changes are much more pronounced in both the COX-1 null and COX-2 null mice relative to wild type controls. Interestingly, there are no significant differences in BALF cells or lung histopathology between the genotypes following LPS exposure. Thus, the balance of COX-1 and COX-2 is important in regulating the physiologic but not the inflammatory responses to inhaled LPS. Following vanadium pentoxide (V2O5) exposure, COX-2 null mice, but not COX-1 null mice, have increased acute lung inflammation and develop more lung fibrosis (increased lung hydroxyproline and enhanced trichrome staining). We have also utilized a pulmonary influenza infectivity model to evaluate host resistance and to determine if there are defects in innate or adaptive immune responses to viral infection in COX-1 null and COX-2 null mice. Infection induced more severe illness in COX-1 null mice and less severe illness in COX-2 null mice in comparison to wild type mice as evidenced by body weight and body temperature changes. Mortality was significantly reduced in COX-2 null mice. Consistent with the clinical observations, COX-1 null mice had enhanced inflammation and earlier appearance of pro-inflammatory cytokines in the BAL fluid, whereas the inflammatory and cytokine responses were blunted in COX-2 null mice. However, lung viral titres were markedly elevated in COX-2 null mice relative to wild type and COX-1 null mice on day 4 of infection. Levels of prostaglandin E2 were reduced in COX-1 null airways whereas cysteinyl leukotrienes were elevated in COX-2 null airways following infection. Thus, deficiency of COX-1 and COX-2 leads to contrasting effects in the host response to influenza infection, and these differences are associated with altered production of prostaglandins and leukotrienes following infection. The response of COX-deficient mice varies depending on the environmental stimulus. We have recently developed transgenic mice with lung-specific overexpression of human COX-1 (murine CC10 promoter driven). These mice are being used to determine the effect of increased COX-derived eicosanoids on lung function at baseline and after various environmental stimuli.

我们正在研究环加氧酶在肺部对环境因子反应中的作用。在基线时，与野生型或COX-2缺失小鼠相比，COX-1缺失小鼠的肺前列腺素E2水平较低，但在基础肺功能或肺组织病理学方面，基因型之间没有显著差异。在过敏原（卵清蛋白）致敏/暴露后，COX-1缺失和COX-2缺失小鼠的肺部炎症指数明显高于野生型小鼠。过敏性COX-1缺失小鼠气道嗜酸性粒细胞数量增加，CD3+/CD4+淋巴细胞（Th细胞）数量增加。来自过敏性COX-1空气道的肺泡巨噬细胞表现出激活的生化和形态学证据。过敏性COX-1缺失小鼠的支气管肺泡灌洗液（BALF）中Th2细胞因子IL-4、IL-5和IL-13水平显著升高，LTB4和半胱氨酸白三烯水平升高，趋化因子TARC和eotaxin水平升高。COX-1缺失小鼠的这些变化与BALF - IgE水平升高和MUC5AC生成/粘蛋白分泌增加有关。此外，在COX-1过敏小鼠和COX-2过敏小鼠的肺中，粘附分子VCAM-1和ICAM-1的表达均增加。过敏性COX-1缺失小鼠肺顺应性降低，过敏原诱导的支气管收缩增加，对吸入甲胆碱表现出高反应性。我们还研究了COX基因破坏对肺部对其他环境相关因子的反应的影响，包括吸入内毒素（细菌脂多糖，LPS）、五氧化二钒和流感病毒。LPS暴露后，所有小鼠均表现出支气管收缩增加和甲胆碱高反应性；然而，与野生型对照相比，这些变化在COX-1缺失和COX-2缺失小鼠中更为明显。有趣的是，在LPS暴露后，不同基因型之间的BALF细胞或肺组织病理学没有显著差异。因此，COX-1和COX-2的平衡在调节吸入LPS的生理反应中是重要的，而不是炎症反应。暴露于五氧化二钒（V2O5）后，COX-2缺失小鼠（而非COX-1缺失小鼠）急性肺部炎症增加，肺纤维化加重（肺羟脯氨酸增加，三色染色增强）。我们还利用肺流感感染性模型来评估宿主耐药性，并确定COX-1缺失和COX-2缺失小鼠对病毒感染的先天或适应性免疫反应是否存在缺陷。与野生型小鼠相比，感染导致COX-1缺失小鼠更严重的疾病，而COX-2缺失小鼠的疾病较轻，这一点可以从体重和体温变化中得到证明。COX-2缺失小鼠的死亡率显著降低。与临床观察一致，COX-1缺失小鼠的炎症增强，BAL液中促炎细胞因子的出现更早，而COX-2缺失小鼠的炎症和细胞因子反应减弱。然而，在感染的第4天，与野生型和COX-1缺失小鼠相比，COX-2缺失小鼠的肺病毒滴度明显升高。感染后，COX-1空气道中前列腺素E2水平降低，而COX-2空气道中半胱氨酸白三烯水平升高。因此，缺乏COX-1和COX-2导致宿主对流感感染的不同反应，这些差异与感染后前列腺素和白三烯产生的改变有关。cox缺陷小鼠的反应随环境刺激而变化。我们最近开发了具有人类COX-1（小鼠CC10启动子驱动）肺特异性过表达的转基因小鼠。这些小鼠被用来确定在基线和各种环境刺激后增加cox衍生的二十烷类化合物对肺功能的影响。