Transcriptional Control of Submucosal Gland Formation and Function

描述(申请人提供)：呼吸道经常暴露在微生物病原体和颗粒中，但受到多层宿主防御系统的保护，以维持肺功能和无菌。粘液清除、粘液产生和宿主防御的严重缺陷伴随着常见的慢性肺部疾病，包括囊性纤维化(CF)、慢性阻塞性肺疾病和哮喘。这些疾病的并发症包括粘液化生、粘液过度生成或浓缩、炎症和肺部感染的易感性。本研究旨在探讨慢性阻塞性肺疾病相关黏液纤毛清除缺陷的分子机制。这项工作基于初步数据，证明了1)一个新的转录因子网络，它决定了衬里发育中的气管和支气管的呼吸道上皮细胞(AECs)的图案化和分化，以及粘膜下腺(SMGs)的形成，黏膜下腺(SMGs)将大部分液体、电解质和宿主防御蛋白分泌到呼吸道表面；2)AECs和SMGs的图案化、生长、分化和基因表达受到囊性纤维化跨膜电导调节因子(CFTR)缺乏的影响。这一应用将检验一种假设，即PAX9及其相关的转录网络在发育和成熟的呼吸道中AEC和SMG的形态发生和功能的调节中发挥关键作用。这一建议将利用转基因小鼠，在体内和体外，PAX9和与PAX9相关的基因被有条件地删除或添加到发育和成熟的呼吸道上皮中。PAX9和相关蛋白调节AEC和SMG形成和功能的关键基因和过程的分子和细胞机制将被评估。所提出的依赖PAX9的调节程序在CFTR缺陷猪和小鼠的肺并发症的发病机制中的作用将被确定。这项建议试图确定AEC和SMG的形态发生和功能的细胞和分子基础，与粘液纤毛清除缺陷引起的反复感染的发病机制相关。

DESCRIPTION (provided by applicant): The respiratory tract is constantly exposed to microbial pathogens and particles, but is protected by a multitiered host defense system that serves to maintain lung function and sterility. Severe defects in mucociliary clearance, mucus production, and host defense accompany common chronic lung diseases, including cystic fibrosis (CF), chronic obstructive pulmonary disease, and asthma. These disorders are complicated by mucus metaplasia, mucus hyperproduction or inspissation, inflammation, and susceptibility to pulmonary infection. This application seeks to determine the molecular mechanisms underlying deficits in mucociliary clearance associated with pulmonary disease in CF. The work is based on preliminary data demonstrating 1) a novel network of transcription factors that determines both the patterning and differentiation of airway epithelial cells (AECs) lining the developing trachea and bronchi, and the formation of submucosal glands (SMGs) that secrete the majority of fluids, electrolytes, and host defense proteins onto the airway surface and 2) that patterning, growth, diferentiation, and gene expression of AECs and SMGs are influenced by the lack of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). This application will test the hypothesis that PAX9 and an associated transcriptional network play a critical role in the regulation of AEC and SMG morphogenesis and function in the developing and mature airway. This proposal will utilize transgenic mice in which PAX9 and genes associated with PAX9 are conditionally deleted or added to the developing and mature airway epithelium in vivo and in vitro. The molecular and cellular mechanisms by which PAX9 and associated proteins regulate genes and processes critical for AEC and SMG formation and function wil be assessed. The role of the proposed PAX9-dependent regulatory program in the pathogenesis of the pulmonary complications of CF will be determined in CFTR-deficient pigs and mice. This proposal seeks to determine the cellular and molecular basis underlying AEC and SMG morphogenesis and function relevant to the pathogenesis of recurrent infections caused by defects in mucociliary clearance.