The Role of Gelatinase B in Terminal Airway Remodeling

描述（由申请人提供）：终末气道是许多慢性肺部疾病（最明显的是COPD）中结构和功能异常的部位，但对终末气道内衬上皮细胞的细胞和分子生物学知之甚少。 最近的观察表明基质金属蛋白酶明胶酶B（MMP-9; gel B）在末端气道上皮的功能中起重要作用。 凝胶B缺陷（“敲除”）小鼠在暴露于博来霉素后未显示出野生型小鼠中所见的肺泡细支气管化，它们也未显示出暴露于萘后末端气道上皮的正常快速修复，萘是一种引起末端气道内衬的Clara细胞坏死的试剂。终末气道上皮中凝胶B表达的调控尚不清楚。 最近的研究表明，细胞外基质金属蛋白酶诱导剂，EMMPRIN，是突出的肺泡和终端气道上皮细胞在人类肺纤维化和小鼠博莱霉素后。 拟进行的研究将检验：（1）Clara细胞表达gel B是否可以挽救gel B“敲除”小鼠中博莱霉素后肺泡细支气管化和萘后上皮修复的缺陷;（2）Clara细胞的迁移特性以及gel B与Clara细胞迁移的关系;（3）EMMPRIN对肺细胞和完整肺表达基质金属蛋白酶（尤其是gel B）的影响。 为了评估Clara细胞凝胶B对博来霉素后肺泡细支气管化和萘后终末气道修复的作用，将在凝胶B敲除背景下产生转基因小鼠，其将以四环素诱导的方式在Clara细胞中表达凝胶B。 为了研究Clara细胞的迁移和凝胶B的作用，将从凝胶B缺陷型和野生型小鼠中分离Clara细胞，并根据对各种趋化因子的反应以及与各种细胞外基质组分的接触来定量其迁移。 为了确定EMMPRIN是否影响凝胶B和其他基质金属蛋白酶的表达，将各种类型的肺细胞，包括Clara细胞暴露于重组EMMPRIN并评价基质金属蛋白酶的表达。 总之，这些研究将有助于更好地了解终末气道上皮细胞的生物学，这是许多慢性肺部疾病，特别是COPD的中心部位。

DESCRIPTION (provided by applicant): The terminal airways are sites of abnormal structure and function in a number of chronic lung disorders, most notably COPD, yet relatively little is known about the cell and molecular biology of the epithelial cells lining terminal airways. Recent observations indicate an important role of the matrix metalloproteinase gelatinase B (MMP-9; gel B) in the function of terminal airway epithelium. Gel B-deficient ("knockout") mice do not show the alveolar bronchiolization seen in wild type mice after exposure to bleomycin, nor do they show the normal rapid repair of terminal airway epithelium after exposure to napthalene, an agent that causes necrosis of the Clara cells lining the terminal airways. The regulation of gel B expression in terminal airway epithelium is not well understood. Recent studies have shown that extracellular matrix metalloproteinase inducer, EMMPRIN, is prominent in alveolar and terminal airway epithelium in human pulmonary fibrosis and after intratracheal bleomycin in mice. The studies proposed will examine: (1) whether gel B expression by Clara cells can rescue the defects in alveolar bronchiolization after bleomycin and epithelial repair after napthalene in gel B "knockout" mice; (2) the migratory properties of Clara cells and the relationship of gel B to Clara cell migration; and (3) the effects of EMMPRIN on the expression of matrix metalloproteinases, especially gel B, by lung cells and the intact lung. To assess the role of Clara cell gel B on alveolar bronchiolization after bleomycin and terminal airway repair after napthalene, transgenic mice will be generated on the gel B knockout background which will express gel B in Clara cells in a tetracycline-inducible manner. To study the migration of Clara cells and the role of gel B, Clara cells will be isolated from gel B-deficient and wild type mice and their migration quantified in response to various chemotactic factors and in relation to contact with various extracellular matrix components. To determine whether EMMPRIN affects expression of gel B and other matrix metalloproteinases, various types of lung cells, including Clara cells, will be exposed to recombinant EMMPRIN and evaluated for matrix metalloproteinase expression. Taken together, the studies proposed will contribute to better understanding of the biology of terminal airway epithelium, a site that is central in many chronic lung disorders, especially COPD.