Project 1: Mucociliary Transport in Cystic Fibrosis Lung Disease

项目1 项目概要 尽管开发了新疗法，囊性纤维化（CF）仍然是一种缩短寿命的疾病。早期 旨在纠正最初宿主防御缺陷并预防/减少感染和粘液的干预措施 积累可以显着改善 CF 肺部疾病的病程。众所周知，突变 编码HCO3-和Cl-传导通道CFTR的基因导致CF；尽管有这些知识，但缺乏 复制人类 CF 的动物模型掩盖了疾病的起源。 CF猪为我们提供了 在很早的时间点研究 CF 肺的前所未有的机会。 CF猪出生时缺乏气道 但在出生后几周内，CF 猪会自发地出现 CF 肺病的标志性特征 包括气道炎症、感染、粘液积聚和重塑。我们之前发现CF 猪在出生当天至少有两个宿主防御缺陷：a）气道表面活性降低 液体抗菌剂； b) 胆碱能刺激后粘液纤毛运输（MCT）缺陷， 引起粘膜下腺分泌大量粘液。最近的机制研究表明，CF 粘膜下腺分泌粘液丝，有时在进入气道后不会破裂 表面。相反，它们仍然附着在腺管上，阻碍 MCT。这些发现直接联系 MCT 受损导致阴离子转运丧失，表明 MCT 缺陷是主要异常。我们的中央 假设 CFTR 缺失会导致 MCT 缺陷，从而导致早期 CF 气道疾病。因此，有 迫切需要更好地了解 MCT 缺陷的根本机制，这些缺陷是否是 受疾病进展的影响，以及如何纠正它们。在这个项目的新方向上，我们 我们的研究重点是未能从 CF 粘膜下腺管分离并浓缩的粘液丝 我们努力确定此缺陷是否可以纠正。我们将研究以下具体目标：(1) 哪些因素影响粘液链的形成、断裂和清除？我们的工作假设是 改变粘液链形成和释放的化学环境会影响粘液链 破损和间隙。 (2) 在 CF 气道中，是否诱导粘膜下腺释放粘液丝 导管恢复MCT？我们假设释放卡住的粘液丝将逆转 MCT 缺陷，从而 增强 CF 中的 MCT。 (3) 早期 CF 疾病进展和病毒感染如何影响 MCT？ CF猪 出生时存在宿主防御缺陷，并在几周内出现气道疾病。在这里我们将 了解早期感染、炎症和粘液积聚如何影响 CF 猪的 MCT。通过专注于 早期 CF 气道疾病的发病机制，我们希望加速发现新的治疗干预措施 并确定早期 CF 的终点。

PROJECT 1 PROJECT SUMMARY Despite the development of new therapies, cystic fibrosis (CF) remains a life-shortening disease. Early interventions aimed at correcting the initial host defense defects and preventing/reducing infection and mucus accumulation could dramatically improve the course of CF lung disease. It is widely known that mutations in the gene encoding the HCO3- and Cl--conducting channel CFTR cause CF; in spite of this knowledge, lack of an animal model that replicates human CF has obscured the origins of disease. CF pigs provided us with the unprecedented opportunity to investigate the CF lung at very early time points. At birth, CF pigs lack airway disease, but within weeks of birth CF pigs spontaneously develop hallmark features of CF lung disease including airway inflammation, infection, mucus accumulation, and remodeling. We previously found that CF pigs have at least two host defense defects on the day that they are born: a) reduced activity of airway surface liquid antimicrobials; and b) defective mucociliary transport (MCT) following cholinergic stimulation, which elicits copious mucus secretion from submucosal glands. Recent mechanistic investigations revealed that CF submucosal glands secrete strands of mucus that sometimes do not break free after emerging onto the airway surface. Instead, they remain attached to the gland ducts, hindering MCT. These findings directly link impaired MCT to loss of anion transport, indicating that defective MCT is a primary abnormality. Our central hypothesis is that loss of CFTR causes MCT defects that contribute to early CF airway disease. Thus, there is a critical need to better understand the underlying mechanism for MCT defects, whether these defects are impacted by disease progression, and how they might be corrected. In a new direction for this project, we focus our studies on the mucus strands that fail to detach from the CF submucosal gland duct and concentrate our efforts towards determining if this defect is correctable. We will investigate the following Specific Aims: (1) Which factors impact mucus strand formation, breakage, and clearance? Our working hypothesis is that altering the chemical environment into which mucus strands are formed and released will impact strand breakage and clearance. (2) In CF airways, does inducing release of mucus strands from submucosal gland ducts restore MCT? We postulate that releasing stuck mucus strands will reverse MCT defects, thereby enhancing MCT in CF. (3) How does early CF disease progression and viral infection impact MCT? CF pigs have host defense defects present at birth and within weeks of age develop airway disease. Here we will discover how early infection, inflammation, and mucus accumulation affect MCT in CF pigs. By focusing on the pathogenesis of early CF airway disease, we hope to accelerate discovery of new therapeutic interventions and identify endpoints for early CF.