Mucin glycoproteins (MUC) (MUC)

Mucin glycoproteins are high-molecular-weight, heavily O-glycosylated proteins that constitute the primary structural framework of the respiratory mucus gel (Source: PMC6529204). In the human airways, the two dominant gel-forming mucins are MUC5AC, primarily secreted by surface goblet cells, and MUC5B, produced by both goblet cells and submucosal glands (Source: UniProt P35226, Q9HC84). These proteins play a critical role in the innate immune system by trapping inhaled pathogens and debris, which are subsequently cleared from the lungs via the mucociliary escalator (Source: PubMed 29030118). However, in pathological conditions such as Chronic Obstructive Pulmonary Disease (COPD), asthma, and cystic fibrosis, mucin hypersecretion and altered glycosylation lead to increased mucus viscosity and airway obstruction (Source: StatPearls NBK538311). Pharmacological intervention typically involves mucolytic agents like N-acetylcysteine, which reduce mucus elasticity by cleaving disulfide bonds between mucin monomers, or mucokinetics that enhance clearance (Source: PubChem CID 12035). Understanding the balance between MUC5AC and MUC5B is increasingly recognized as vital for developing targeted therapies for chronic lung diseases.

Other names

Airway mucinsGel-forming mucinsTracheobronchial mucinsMUC5ACMUC5BAirway secretions

Mucolytic agents (e.g., N-acetylcysteine) reduce mucus viscosity by cleaving the disulfide bonds that cross-link mucin polymers, while mucoregulators (e.g., carbocisteine) influence the production and secretion of mucins from goblet cells, and mucokinetics (e.g., guaifenesin) enhance the effectiveness of cough or ciliary transport (Source: PubMed 24841175, StatPearls NBK538311).