Role of Airway Epithelium in Mycoplasma Pathogenesis

气道上皮在支原体发病机制中的作用

• 批准号: 6955248
• 负责人: CAROL B BASBAUM
• 金额: $ 42.36万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6955248
• 关键词: Mycoplasma; RNA interference; biological signal transduction; cadherins; cell motility; cellular pathology; chromatin immunoprecipitation; gel mobility shift assay; gene deletion mutation; gene expression; inflammation; laboratory rat; mucus; phenotype; protein protein interaction; respiratory epithelium; respiratory function; respiratory infections; secretion; yeast two hybrid system

Mucus hypersecretion is a major clinical symptom of cystic fibrosis, asthma, and COPD. A consequence is the formation of mucus plugs in small airways, which are sites of recurrent infection. These plugs also bring about oxygen insufficiency. The lethality of each of the above conditions is directly linked to the presence of excessive mucus. The substrate for hypersecretion is the pathological growth of airway mucus glands, which is reflected in increased gland:wall ratios consistently found at autopsy in these patients. The molecular mechanisms responsible for initiating gland growth in adult airways are unknown, but once understood, could open the way for drug development to help these patients. Based on our preliminary data and its similarity to findings in other systems, we propose that Mycoplasma elicits a convergence of stimuli at epithelial mesenchymal junctions leading to Lef-1/beta catenin overexpression and subsequent changes in gene expression in select epithelial cells. Among the genes so affected are E-cadherin and EMMPRIN. While downregulation of E-cadherin promotes bud formation by weakening adherens junctions, upregulation of EMMPRIN can be expected, based on our in vitro observations, to increase motility of the non-adherent cells. In Aim 1, we will examine the dependence of gland bud formation on Lef-1, beta catenin, wnt and EMMPRIN, using selective siRNAs directed against each protein both in vitro and in vivo. In Aim 2, we will test the hypothesis that Lef-1/beta catenin upregulation in gland buds is directly responsible for upregulation of EMMPRIN, whose promoter indeed contains putative Lef1-beta catenin response elements. In Aim 3, we will identify the molecular changes in EMMPRIN-overexpressing epithelial cells contributing to the hypermotile phenotype. The results of the proposed studies should provide a molecular model of mucus gland formation in lung disease and suggest novel targets for the development of drugs to block hypersecretion and prolong life.

粘液分泌是囊性纤维化，哮喘和COPD的主要临床症状。结果是在小气道中形成粘液塞，这些气道是复发性感染部位。这些插头还带来了氧气不足。上述每种条件的杀伤力与过度粘液的存在直接相关。过度分泌的底物是气道粘液腺体的病理生长，在这些患者的尸检时始终发现腺体的壁比反映。分子 导致成人气道启动腺体生长的机制尚不清楚，但一旦理解，可以为药物开发提供帮助以帮助这些患者的道路。基于我们的初步数据及其与其他系统中发现的相似性，我们建议支原体在上皮间质连接处引起刺激的收敛性，从而导致LEF-1/βcatenin过表达，并在选定上皮细胞中基因表达的后续变化。在如此受影响的基因中，是电子钙黏着蛋白和艾姆普林。虽然e-钙粘着蛋白的下调通过削弱粘附连接来促进芽的形成，但根据我们的体外观察结果，可以预期emmprin的上调，以增加非粘附细胞的运动性。 在AIM 1中，我们将使用针对每种蛋白质在体外和体内针对每种蛋白质的选择性siRNA，研究腺体芽形成对LEF-1，β蛋白酶，Wnt和Emmprin的依赖性。在AIM 2中，我们将检验以下假设：腺体芽中的LEF-1/β链球菌上调直接负责Emmprin的上调，Emmprin的启动子确实包含假定的LEF1-beta catenin响应元件。在AIM 3中，我们将确定促成高电动表型的过表达Emmprin表达的上皮细胞的分子变化。拟议的研究的结果应提供肺部疾病中粘液腺形成的分子模型，并提出用于开发药物以阻止过度分泌和延长寿命的新目标。