Nasal and sinus mucins and mucosal glycoproteins bearing sialic acid and sulfate groups

Nasal and sinus mucins, primarily MUC5AC and MUC5B, are large, heavily glycosylated proteins that form the primary physical and chemical barrier of the upper respiratory tract (Thornton et al., 2008, Annu Rev Physiol). These glycoproteins are characterized by extensive O-linked glycans terminating in sialic acid and sulfate groups, which provide a negative charge and specific binding sites for both commensal and pathogenic microbes (Scharfman et al., 1995, Glycobiology). In the context of viral infections, such as influenza, these sialic acid residues serve as essential attachment points for viral hemagglutinin (Matrosovich et al., 2004, PNAS). Beyond acting as a scaffold for viral entry, these mucins play a critical role in mucociliary clearance, trapping inhaled particles and pathogens for removal (Lillehoj et al., 2013, Front Biosci). In chronic inflammatory conditions like rhinosinusitis, the overproduction or altered glycosylation of these mucins leads to airway obstruction and persistent infection (Lamblin et al., 2001, Glycoconj J). Therapeutic strategies targeting these molecules include mucolytics like N-acetylcysteine that reduce mucus viscosity and decoy receptors like iota-carrageenan that block viral adherence to the sialylated surfaces (Grassauer et al., 2008, Virol J).

Other names

Sinonasal mucinsRespiratory mucosal glycoproteinsSialylated nasal mucinsSulfated airway glycoproteinsUpper respiratory tract mucins

Competitive inhibition of viral attachment, Disulfide bond reduction to decrease viscosity, Osmotic hydration of the mucus layer, and inhibition of viral neuraminidase-mediated cleavage from sialic acid residues.