Purchase this article with an account.
A. S. Tisdale, U. Jurkunas, S. Spurr-Michaud, I. K. Gipson; As Corneal Epithelial Cells Age and Flatten at the Ocular Surface, the Amount of Membrane Mucin Decreases. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1948.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The normal process of epithelial cell turnover in the cornea involves apical cell flattening and desquamation. The purpose of this study was to determine if membrane-associated mucins MUC1 and MUC16 change with the increase in apical cell surface size during this differentiation process.
MUC1, MUC16 and a carbohydrate epitope on MUC16 (H185) were immunohistochemically localized on apical corneal epithelial cell surfaces of human epithelial flaps removed by epikeratome during laser surgery (N=4). In addition, MUC16 was localized on apical cells of a human corneal epithelial cell line cultured to differentiate and express mucins (HCLE, N=2). Five images per biopsy (20-40 cells per image) for each antibody localization and three images of HCLE cultures (25-40 cells per image) were photographed. Cell size and amount of antibody binding were determined using Adobe Photoshop. Statistical significance was determined using Spearman Rank Correlation (Instat3).
A significant inverse correlation between the amount of binding of antibodies to MUC1, MUC16 and H185 and cell size was observed on the apical cells of the native epithelia: MUC1 (r= -0.32, p<0.0001), MUC16 (r= -0.44, p<0.0001), and H185 (r= -0.36, p<0.0001). A similar correlation of decreased MUC16 with increased cell size was found in differentiated HCLE cells (r= -0.41, p<0.0001).
As corneal epithelial cells enlarge with cell age at the ocular surface, the amount of membrane mucins MUC1 and MUC16 on their surface decreases. The HCLE cells, induced to differentiate in vitro, mimic the native corneal epithelium with less MUC16 on apical cells with increased size. Loss of both MUC16 and H185, a carbohydrate epitope on MUC16, from the cells at the ocular surface indicates that the decrease is a result of constituitive release of the ectodomain of MUC16, rather than a change in glycosylation of the mucin. Diminution of the mucins on apical cells may presage and facilitate desquamation of the oldest cells from the ocular surface.
This PDF is available to Subscribers Only