Tear film mucin and corneal epithelial cell surface glycocalyx (null)

Tear film mucins are high-molecular-weight glycoproteins that form a crucial part of the glycocalyx coating the corneal epithelial cell surface. These membrane-associated mucins (principally MUC1, MUC4, MUC16) extend from the epithelial membrane via microvilli and microplicae, bind water, and create a hydrophilic, lubricated interface that stabilizes the tear film, supports barrier function, and protects against physical and microbial insult[1][7][8]. The corneal epithelial cell surface glycocalyx rich in these mucins enables tear film adhesion to the ocular surface and minimizes friction with blinking, while also participating in wound healing and, possibly, signal transduction responses to ocular surface damage[3][9]. Deficiency or loss of mucins leads to dry eye, increased epithelial permeability, and vulnerability to infection[1][9]. Drugs that increase mucin production or improve glycocalyx integrity are being developed to tackle dry eye and related conditions[3][5].

Other names

Membrane-associated mucins (MAMs)Ocular surface mucinsMucin glycocalyxCell-bound mucinsGlycocalyx of the corneal epithelium

Upregulation of mucin gene/protein production Enhanced secretion of mucins Promotion of glycocalyx integrity Improvement of epithelial barrier function Modulation of inflammatory response and signaling