Glycosylation pathways of human corneal and conjunctival epithelial cell mucins. (December 2018) - Brockhausen, Inka
Abstract: 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, Galβ1-3GalNAcα, and core 2, GlcNAcβ1-6(Galβ1-3)GalNAcα 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 TNFα suggest that epithelial O-glycosylation changes in a dynamic fashion during inflammatory stimuli of the eye surface. Graphical abstract: Highlights: Human corneal and conjunctival epithelial cells were grown to study mucin glycosylation pathways. Eye cells have the enzymes that synthesize O-glycans with core 1 and 2 but not core 3 and 4. Eye cells have GlcNAc-transferases involved in N-glycan branching. TNFα treatment of cells leads to dynamic changes of glycosyltransferase activities. The results supplement those from structural and RNA expression studies.