Functions of MUC16 in Corneal Epithelial Cells

Abstract

These results suggest that MUC16 is a multifunctional molecule linked to the actin cytoskeleton. The expression of MUC16 in the ocular surface glycocalyx helps provide a disadhesive protective barrier for the epithelial surface.

Focus on Molecules: Human mucin MUC16

“…Although the function of the association of MUC16 with the actin cytoskeleton is unclear, it may facilitate surface cell membrane folding. Density of microplicae on cells of the ocular surface epithelium decreases as cells age at the surface, and they decrease in cells in dry eye (Blalock, T. et al, 2007).…”

“…This heavily O-glycosylated glycoprotein is found on the apical membranes of the wet-surfaced epithelial cells of both the human cornea ( Figure 1A) and conjunctiva; it is especially prominent specifically on the tips of surface microplicae ( Figure 1B). It is also found on the surfaces of respiratory tract epithelia and female reproductive tract epithelia (for review see (Blalock, T. et al, 2007)). MUC16, also known as the CA125 antigen, was cloned from an ovarian cancer cell line, OVCAR-3, and was mapped to chromosome 19p13.2 (for review see (Gipson, I.K.…”

“…In studies using a human telomerase immortalized human corneal epithelial cell line in which MUC16 expression was stably knocked down using siRNA methods, adherence of Staphylococcus aureus to epithelial cells increases, indicating that the mucin prevents adhesion of pathogens. In addition, the mucin serves as a barrier to penetrance of agents into epithelial cells, since knockdown of the mucin increases penetrance of rose bengal dye (Blalock, T. et al, 2007). Rose bengal is used clinically to diagnose dry eye, as it penetrates areas of epithelium where protection has been compromised.…”

The Role of MUC16 Mucin (CA125) in the Pathogenesis of Ovarian Cancer

“…MUC16 is expressed at low levels in the normal airway epithelium but levels can increase in some chronic conditions such as cystic fibrosis (Hattrup et al, 2008;Davies et al, 2007;Gronowitz et al, 2003). MUC16 is expressed at the apical surface of the ocular and conjonctival epithelium where it is part of the glycocalyx protecting corneal cells from bacterial infections and dryness (Argueso et al, 2003;Blalock et al, 2007). MUC16 is also found in lacrimal glands (Jäger et al, 2007).…”

Conflicting Views on the Molecular Structure of the Cancer Antigen CA125/MUC16

“…MUC16 was expressed in normal tissues such as the surfaces of respiratory tract epithelia and female reproductive tract epithelia [30]. Of particular interest is the expression of MUC16 by the human ocular surface epithelia [31].…”