Glycosylation pathways of human corneal and conjunctival epithelial cell mucins

Mucin glycoproteins on the ocular surface are rich in O-glycans and have important roles in the protection from physical, chemical and microbial impact. In this work, we have cultured human corneal and conjunctival epithelial cells to examine the glycosyltransferase activities that synthesize the O-glycans of mucins. The results indicate that ocular surface epithelial cells have active enzymes that synthesize O-glycans with sialylated core 1, Gal beta 1-3GalNAc alpha, and core 2, GlcNAc beta 1-6(Gal beta 1-3)GalNAc alpha structures which corresponds to previous structural studies. Eye cells also have enzymes that synthesize complex N-glycans that are found on mucins. Results from treatment of eye cells with TNF alpha suggest that epithelial O-glycosylation changes in a dynamic fashion during inflammatory stimuli of the eye surface.