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M.S. Chang, S.–H. Presley, J.R. Backstrom, D.M. Bader; Regulation of Tight Junction Formation by Bves in Human Corneal Epithelial Cells . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4773.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Bves (blood vessel epicardial substance), is a novel adhesion molecule expressed in epithelial structures of the developing and adult eye. Previous studies indicate Bves to have a role in human corneal epithelial growth and regeneration. We hypothesize that Bves is important in the regulation of epithelial cellular migration and differentiation through initiation and maintenance cell–cell contact, specifically in the formation and maintenance of tight junctions (TJ). Methods: Human corneas were analyzed for Bves expression by immunfluorescence staining. Stably transfected clones over–expressing full–length chicken Bves (WTX) and a dominant negative truncated chicken Bves (DN) were generated from a human corneal epithelial cell line (HCE). Isolates were analyzed for alterations in TJ formation. Functional studies were also carried out, including cellular growth rate, transwell electrical resistance (TER), and cellular migration in a cell culture wounding model. Results: Bves and ZO1, a component of TJ, have the same expression pattern at the cell surface in all layers of the human corneal epithelium. HCE cells also exhibited colocalization of Bves and ZO1 at sites of cell–cell contact. In the DN cells, the normal trafficking of Bves is altered, with Bves mainly found in the cytoplasm. With disruption of Bves, ZO1 protein expression level is reduced and disrupted at sites of cell–cell contact. The DN cells also exhibited altered morphology, accelerated growth rate, and inability to form a complete monolayer. In the wounding model, disruption of Bves resulted in rapid but disorganized coverage of the wound area. In contrast, WTX cells over–expressing Bves demonstrated phenotypes essentially opposite of the DN cells. WTX cells formed a monolayer in a very organized cobblestone pattern. Bves and ZO1 expression at cell–cell contact was well defined and continuous at cell borders. On Western analysis, we did not detect any changes in ZO1 expression level compared to HCE cells, but TER, a functional measurement of TJ formation, was doubled. WTX cells also exhibited the slowest rate of growth and delayed coverage in the wounding model. Conclusions: These results support our hypothesis that Bves is critical in the initiation and maintenance of cell–cell contact through the formation of maintenance of TJ in the human cornea. The broader implication is that Bves may play an important role in regulating corneal epithelial cell growth and maintaining the highly organized structure of the human corneal epithelium.
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