Mucin glycoprotein disulfide bonds and reactive oxygen species

Mucin glycoproteins, such as MUC5AC and MUC5B, are the primary structural elements of the mucus gel that protects respiratory and gastrointestinal tracts (Thornton et al., 2008). These glycoproteins form large, complex polymers through intermolecular disulfide bonds, which provide the mucus with its characteristic viscoelastic properties. In chronic inflammatory airway diseases, such as cystic fibrosis and COPD, mucus becomes pathologically thick due to hypersecretion and increased cross-linking, often exacerbated by reactive oxygen species (ROS) that promote oxidative stress and further mucin production (Kirkham & Rahman, 2006). Therapeutic strategies target this system by using mucolytic agents that contain free thiol groups to reduce disulfide bonds, thereby breaking down the polymers and lowering mucus viscosity (Sadowska, 2012). Furthermore, these agents often act as antioxidants to neutralize ROS, helping to restore effective mucociliary clearance and reduce the inflammatory burden on the epithelium (StatPearls, 2023).

Other names

Mucin polymersMucus disulfide cross-linksAirway mucus gelMucin disulfide bridgesOxidative mucus matrix

Reduction of intermolecular disulfide bonds via thiol-disulfide exchange to fragment mucin polymers and direct scavenging of reactive oxygen species to mitigate oxidative stress (Sadowska, 2012; StatPearls, 2023).