Airway mucoprotein disulfide bonds

Airway mucoprotein disulfide bonds are the critical chemical linkages that stabilize the complex, three-dimensional network of gel-forming mucins, primarily MUC5AC and MUC5B, within the respiratory tract (Bonser et al., 2016, JCI Insight). These covalent bonds form between cysteine-rich domains of mucin monomers, facilitating the polymerization required for mucus to exhibit its characteristic viscoelastic properties (Fahy and Dickey, 2010, NEJM). In pathological conditions such as cystic fibrosis and chronic obstructive pulmonary disease (COPD), the density of these disulfide cross-links increases, often exacerbated by oxidative stress, resulting in thick, tenacious mucus that obstructs the airways and impairs mucociliary clearance (Sadowska, 2012, Paediatric Respiratory Reviews). Therapeutic intervention focuses on the use of thiol-containing mucolytic agents, such as N-acetylcysteine, which act as reducing agents to break these disulfide bonds. By converting the bridges into individual sulfhydryl groups, these drugs fragment the large mucin polymers into smaller, less viscous components, thereby improving airway patency and facilitating the clearance of secretions (Yuan et al., 2015, Respiratory Medicine).

Other names

Mucin disulfide bondsMucus disulfide bridgesMucoprotein disulfide linkagesIntermolecular disulfide bonds in mucins

Reduction of intermolecular disulfide bonds between mucin polymers into free sulfhydryl groups, leading to the depolymerization of the mucus gel and a reduction in its viscosity (Sadowska, 2012, Paediatric Respiratory Reviews).