Project 1: Mechanism of action of mucolytics in improving mucus clearance in lung disease

患有粘液阻塞性肺疾病(慢性阻塞性肺疾病、慢性阻塞性肺疾病和哮喘)的患者粘液清晰度降低。 由于粘性粘液在他们的呼吸道中堆积。为了了解其发病机制， 这些疾病，有必要了解这两个机制，中介有效的粘液清除在 健康以及这个系统的变化如何导致这些疾病的粘液清除失败。我们的 最重要的假设是，疾病中粘液清除减少是由于 呼吸道粘液的组成和物理性质。根据我们的初步数据，这些变化在 粘液特性的结果是：1)与疾病相关的粘液浓度增加，2)粘液浓度的改变 MUC5AC(主要的哮喘粘蛋白)与MUC5B(主要的CF/COPD粘蛋白)的比率，和/或3) 粘蛋白的氧化会产生额外的交联键。我们假设粘液层的这种变化 会产生更“粘性”(更粘性、粘性、抗撕裂性)的粘液，更难被清除 纤毛跳动和咳嗽的动作。目前还不清楚这些变化是如何发生在 粘液改变粘液的生物物理性质，以及这种变化如何导致粘液清除减少。 为了回答这些问题，目标1中的研究旨在测试改变粘液浓度的效果。 和MUC5AC：MUC5B比例对粘液生物物理性质(流变性、粘附性和粘附力)的影响 摩擦)，以及这种变化如何影响咳嗽和纤毛跳动的粘液清除速度。一旦它发生了 我们的目标是确定疾病如何改变粘液清除，以支持tPPG临床项目3和4 是为了确定如何最好地恢复粘液阻塞患者的粘液清除。我们假设 有两种独立但互补的方法来清除呼吸道中的粘液。这个 最简单的方法是通过水合作用降低粘液浓度。第二种是通过打破 通过使用还原剂降低粘蛋白相对分子质量而产生的粘液。重要的是，我们假设 这种方法可能是相加的/协同的。在目标2中，我们将通过关联约简来检验这些假设 试剂介导的粘蛋白分子量/大小的变化与水合作用介导的粘液变化相结合 集中在粘液生物物理性质的变化上，并评估这些变化对 刺激纤毛和咳嗽引起的粘液清除。在目标3中，我们将评估炎症的作用- 在粘液凝胶的形成过程中介导粘液的氧化，这可能严重地 限制从航道上的净空。我们将检验这一假设，即仅用水合方法是不够的，而是一种 需要水化器和还原剂的组合才能恢复粘液清除。总体而言，这些研究 通过促进我们对机制的理解，预计将支持其他TPPG项目(S) 疾病中有缺陷的粘液清除情况，并确定补水的最有效治疗组合 以及减肥剂，以最大限度地恢复CF、COPD和哮喘患者的粘液清除。

Patients with muco-obstructive lung diseases (CF, COPD, and asthma) suffer from reduced mucus clearability due to accumulation of sticky, adherent, mucus in their airways. In order to understand the pathogenesis of these diseases, it is necessary to understand both the mechanisms that mediate efficient mucus clearance in health and how alterations in this system leads to failed mucus clearance in each of these disorders. Our overarching hypothesis is that reduced mucus clearance in disease is a result of multiple alterations in the composition and physical properties of the airway mucus. Based on our preliminary data, such changes in mucus properties come as a result of: 1) disease-related increases in mucus concentration, 2) alteration in the ratio of MUC5AC (the dominant asthma mucin) vs. MUC5B (the dominant CF/COPD mucin), and/or 3) oxidation of mucins resulting in additional cross-links. We hypothesize that such alterations in the mucus layer will produce a more “sticky” (more viscous, adherent, tear-resistant) mucus that will be harder to be cleared by the action of cilia beating and coughing. There is currently a lack of knowledge of how such changes in the mucus alter the biophysics properties of the mucus and how such changes lead to reduced mucus clearance. To answer these questions, studies in Aim 1 are designed to test the effect of altering mucus concentration and MUC5AC:MUC5B ratio on mucus biophysical properties (rheology, adhesion and cohesion strength, and friction) and how such alterations affect the rate of mucus clearance by cough and cilia beating. Once it has been established how disease alters mucus clearance, our goal, in support of the tPPG clinical projects 3 & 4 is to determine how best to restore mucus clearance in patients with mucus obstructions. We hypothesize that there are two separate, but complementary, approaches to clear adherent mucus from the airways. The simplest is to reduce the mucus concentration, via hydration. The second is by breaking down the structure of mucus through reduction in mucin molecular weight using reducing agents. Importantly, we hypothesize that such approaches may be additive/synergistic. In Aim 2 we will test these hypotheses by correlating reducing agent-mediated changes in mucin molecular weight/size combined with hydration-mediated changes in mucus concentration on changes in mucus biophysical properties and assess the impact of these changes on stimulating both cilia- and cough-mediated mucus clearance. In Aim 3, we will assess the role of inflammation- mediated oxidation of mucus in the formation of a permeant, non-swellable, mucus gel, which can severely limit clearance from the airways. We will test the hypothesis that hydration method alone is not sufficient, but a combination of hydrator plus a reducing agent is required to restore the mucus clearance. Overall, the studies in Project 1 are expected to support other tPPG Projects by advancing our understanding of the mechanism(s) of defective mucus clearance in disease and identifying the most effective therapeutic combination of hydrating and reducing agents to maximally restore mucus clearance in patients with CF, COPD, and asthma.