Airway mucin (MUC)

Airway mucins are high-molecular-weight glycoproteins that serve as the primary structural components of the respiratory mucus layer (Fahy JV, Dickey BF. N Engl J Med. 2010). In the human airways, the gel-forming mucins MUC5AC and MUC5B are the most prevalent, forming a complex viscoelastic network that traps inhaled particles, pathogens, and toxins (Ma J, et al. J Clin Invest. 2018). This mucus layer is essential for mucociliary clearance, a key innate defense mechanism that moves trapped materials out of the lungs (Whitsett JA. N Engl J Med. 2018). However, in pathological conditions such as asthma, COPD, and cystic fibrosis, mucin hypersecretion or biochemical alterations lead to thick, tenacious mucus that causes airway obstruction and promotes chronic infection (Bonser LR, Erle DJ. J Clin Med. 2017). Pharmacological interventions target airway mucins through mucolytic agents, which break the disulfide bonds holding the mucin polymers together, or through agents that modulate mucin production and secretion to improve lung function and reduce exacerbations (Balsamo R, et al. Eur Respir Rev. 2010).

Other names

Respiratory mucinGel-forming mucinMUC5ACMUC5BTracheobronchial mucin

Mucolytic agents reduce mucus viscosity by cleaving disulfide bonds between mucin polymers; mucokinetics enhance clearance by increasing ciliary activity or airflow; mucoregulators inhibit the hypersecretion of mucins at the cellular level.