MUC5AC

MUC5AC is a major gel-forming mucin produced predominantly by airway goblet cells and contributes to the protective mucus barrier that captures inhaled particles and pathogens for mucociliary clearance^[1][2]. Mechanistically, MUC5AC functions within the mucociliary defense system, where secreted polymeric mucins form hydrated mucus networks that support airway barrier integrity and pathogen entrapment^[1][3]. In respiratory disease, altered MUC5AC expression is strongly associated with asthma, chronic bronchitis, chronic obstructive pulmonary disease (COPD), and other muco-obstructive airway disorders characterized by mucus hypersecretion and impaired clearance^[1][4][5]. Experimental and clinical studies further indicate that increased airway MUC5AC concentration correlates with COPD severity, reduced lung function, and elevated risk of disease progression, supporting its value as a disease-associated biomarker and mechanistic readout^[5]. Compared with the related gel-forming mucin MUC5B, MUC5AC exhibits distinct structural organization and biophysical properties, forming highly branched and adhesive mucus networks, whereas MUC5B predominantly forms more linear mucus assemblies involved in airway defense and particle transport^[3][6]. Structural analyses demonstrate that MUC5AC undergoes N-terminal oligomerization and generates viscoelastic gels with increased surface adhesion, properties that may contribute to mucus tethering and airway obstruction in chronic lung disease models^[3]. Therefore, MUC5AC serves as an important experimental target for investigating mucus biology, epithelial remodeling, mucociliary dysfunction, and mechanisms underlying chronic inflammatory airway diseases^[1][3][5].

References: