Alterations In Pulmonary Immune Function And Host Resist

我们正在研究环加氧酶在肺对环境因子的反应中的作用。基线时，考克斯-1基因敲除小鼠的肺前列腺素E2水平低于野生型或考克斯-2基因敲除小鼠，但基因型之间的基础肺功能或肺组织病理学无显著差异。过敏原（卵清蛋白）致敏/暴露后，考克斯-1缺失和考克斯-2缺失小鼠的肺部炎症指数显著高于野生型小鼠。过敏性考克斯-1缺失小鼠的气道具有增加的嗜酸性粒细胞数量和增加的CD 3 +/CD 4+淋巴细胞（Th细胞）数量。过敏性考克斯-1缺失气道的肺泡巨噬细胞显示出活化的生化和形态学证据。来自过敏性考克斯-1缺失小鼠的支气管肺泡灌洗液（BALF）含有显著更高水平的Th 2细胞因子IL-4、IL-5和IL-13，增加水平的LTB 4和半胱氨酰白三烯，以及增加水平的趋化因子TARC和嗜酸性粒细胞趋化因子。考克斯-1缺失小鼠中的这些变化与BALF IgE水平增加和MUC 5AC产生/粘蛋白分泌增加相关。此外，在过敏性考克斯-1和过敏性考克斯-2缺失小鼠的肺中粘附分子VCAM-1和ICAM-1的表达增加。过敏性考克斯-1基因敲除小鼠肺顺应性降低，过敏原诱导的支气管收缩增加，并对吸入乙酰甲胆碱表现出高反应性。我们还研究了考克斯基因的破坏对肺对其他环境相关因子的反应的影响，这些环境相关因子包括吸入性内毒素（细菌脂多糖，LPS）、五氧化二钒和流感病毒。LPS暴露后，所有小鼠均表现出增加的支气管收缩和乙酰甲胆碱高反应性;然而，相对于野生型对照，这些变化在考克斯-1缺失和考克斯-2缺失小鼠中更为明显。有趣的是，在LPS暴露后，基因型之间的BALF细胞或肺组织病理学没有显著差异。因此，考克斯-1和考克斯-2的平衡在调节对吸入LPS的生理反应而不是炎症反应中是重要的。在五氧化二钒（V2 O 5）暴露后，考克斯-2缺失小鼠，而不是考克斯-1缺失小鼠，具有增加的急性肺部炎症和发展更多的肺纤维化（增加的肺羟脯氨酸和增强的三色染色）。我们还利用肺流感传染性模型来评估宿主抗性，并确定考克斯-1无效和考克斯-2无效小鼠中对病毒感染的先天性或适应性免疫应答是否存在缺陷。与野生型小鼠相比，感染在考克斯-1缺失小鼠中诱导更严重的疾病，而在考克斯-2缺失小鼠中诱导较不严重的疾病，如体重和体温变化所证明的。死亡率在考克斯-2缺失小鼠中显著降低。与临床观察结果一致，考克斯-1缺失小鼠的炎症增强，并且在BAL液中促炎细胞因子更早出现，而考克斯-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，相对于野生型和考克斯-1缺失小鼠，考克斯-2缺失小鼠的肺病毒滴度显著升高。前列腺素E2水平在考克斯-1无效气道中降低，而半胱氨酰白三烯在感染后考克斯-2无效气道中升高。因此，考克斯-1和考克斯-2的缺乏导致宿主对流感感染的反应中的对比效应，并且这些差异与感染后异莲心素和白三烯的产生改变有关。COX缺陷小鼠的反应取决于环境刺激。我们最近开发了肺特异性过表达人考克斯-1（鼠CC 10启动子驱动）的转基因小鼠。这些小鼠被用于确定在基线和各种环境刺激后增加的COX衍生类花生酸对肺功能的影响。

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.