Mucinele

Mucinele, commonly known as mucins in English, are high molecular weight glycoproteins that form the protective, gel-like layer of mucus covering many mucosal surfaces. They are produced mainly by goblet cells and other secretory cells of epithelia and are essential for lubrication, barrier function, and defense against pathogens.

Mucinele can be categorized into two main families: secreted gel-forming mucins and membrane-bound mucins. Secreted mucins, such as MUC2, MUC5AC, MUC5B, and MUC6, assemble into hydrated networks that give mucus its viscoelastic properties. Membrane-bound mucins, including MUC1, MUC4, MUC16, and MUC17, are anchored to the cell surface and participate in cell signaling and protection of the epithelial surface. A hallmark of mucinele is their high content of O-linked glycans attached to serine and threonine residues, which impart extensive hydration and charge, contributing to mucus viscosity and pathogen trapping.

Mucinele are distributed throughout the body, with prominent roles in the respiratory, gastrointestinal, and reproductive tracts, as well as on the ocular surface. They moderate microbial communities, stabilize epithelia, and aid in mechanical cleansing. Regulation of mucin expression is dynamic and influenced by cytokines, infections, environmental exposures, and health status.

Alterations in mucinele expression or secretion are linked to several diseases, including cystic fibrosis, chronic bronchitis and asthma, inflammatory bowel disease, and some cancers. They are studied as biomarkers and therapeutic targets, and are measured by techniques such as immunohistochemistry, ELISA, and gene expression analyses.