Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester M13 9PT, U.K.
Biochem Soc Trans. 2018 Oct 19;46(5):1099-1106. doi: 10.1042/BST20170402. Epub 2018 Aug 28.
Mucus plays a vital role in protecting the lungs from environmental factors, but conversely, in muco-obstructive airway disease, mucus becomes pathologic. In its protective role, mucus entraps microbes and particles removing them from the lungs via the co-ordinated beating of motile cilia. This mechanism of lung defence is reliant upon a flowing mucus gel, and the major macromolecular components that determine the rheological properties of mucus are the polymeric mucins, MUC5AC and MUC5B. These large O-linked glycoproteins have direct roles in maintaining lung homeostasis. MUC5B is essential for interaction with the ciliary clearance system and MUC5AC is up-regulated in response to allergic inflammatory challenge. Mucus with abnormal biophysical properties is a feature of muco-obstructive respiratory disease and can result from many different mechanisms including alterations in mucin polymer assembly, mucin concentration and the macromolecular form in mucus, as well as changes in airway surface hydration, pH and ion composition. The abnormal mucus results in defective lung protection via compromised ciliary clearance, leading to infection and inflammation.
黏液在保护肺部免受环境因素的侵害方面起着至关重要的作用，但相反，在黏液阻塞性气道疾病中，黏液变得病态。在其保护作用中，黏液会捕获微生物和颗粒，通过运动纤毛的协调摆动将其从肺部清除。这种肺部防御机制依赖于流动的黏液凝胶，而决定黏液流变特性的主要大分子成分是聚合黏蛋白 MUC5AC 和 MUC5B。这些大型 O-连接糖蛋白在维持肺内稳态方面具有直接作用。MUC5B 对于与纤毛清除系统的相互作用至关重要，而 MUC5AC 在过敏炎症挑战时上调。具有异常生物物理特性的黏液是黏液阻塞性呼吸疾病的特征，可能由许多不同的机制引起，包括黏蛋白聚合物组装、黏蛋白浓度和黏液中大分子形式的改变，以及气道表面水合作用、pH 值和离子组成的改变。异常的黏液会通过削弱纤毛清除来导致肺保护受损，从而导致感染和炎症。
