Abstract
Purpose :
Vision loss due to corneal neovascularization (NV) can result from infection, prolonged use of contact lens, direct or chemical trauma, or immunologic disease. Epithelial membrane protein 2 (EMP2), a four-transmembrane protein and a member of GAS3/PMP22 protein family, is expressed in the corneal epithelium. Previous studies using a corneal burn model demonstrated decreased neovascularization after treatment with an anti-EMP2 antibody. The goal of this study is to expand the initial in vivo studies and examine the effects of anti-EMP2 antibody treatment in human corneal limbal epithelial (HCLE) cells on pro-angiogenic factors in vitro.
Methods :
Human corneal limbal epithelial (HCLE) cells were incubated with anti-EMP2 antibody for 0, 6, 12, 24, 48, and 72 hours. Expression of EMP2 and pro-angiogenic factors were evaluated using immunofluorescence staining and Western blot analysis. Corneal NV was induced in 6-8 week old female Balb/c mice using a NaOH burn method. Mice were treated with an anti-EMP2 or control antibody via subconjunctival injection immediately after the corneal burn. Animals were clinically evaluated to determine the extent of NV. Seven days post treatment, the eyes were enucleated and immunohistochemical studies were performed to identify the vasculature using antibodies against CD34.
Results :
In vitro analysis on HCLE cells treated with anti-EMP2 antibody showed a decrease in EMP2 expression via Western blot and immunofluorescence staining. VEGF expression in the HCLE cells showed a decreased that was concordant with the decrease in EMP2 expression. In the corneal burn in vivo studies, subconjunctival injections of anti- EMP2 resulted in decreased expression of CD34 (p< 0.03) which confirmed the previous clinical observations of decreased vascularization.
Conclusions :
HCLE cells treated with anti-EMP2 antibody alters the expression of EMP2, as expected, and concomitantly decreases VEGF expression by these cells. Compared to control animals, anti-EMP2 antibody treatment reduces CD34 expression in the cornea following an in vivo ocular burn using NaOH and is concordant with the decreased neovascularization observed in a prior study. Modulation of EMP2 expression may provide a new method of preventing corneal neovascularization following injury.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.