Analysis of Fibronectin EDA Expression in RPE Cells Exposed to Growth Factors

Abstract

Abstract: : Purpose:Retinal pigment epithelial (RPE) cells are among cellular constituents thought to be involved in both proliferative vitreoretinopathy and age-related macular degeneration. Their activation in response to injury is mediated by extracellular matrix (ECM) growth factors and cytokines. Fibronectin (FN) EDA is an alternatively spliced embryonic isoform that has been implicated in cellular migration during development and wound healing. The effect of various growth factors on FN EDA expression in fetal RPE cells is investigated here. Methods:FN EDA expression in human fetal RPE cell cultures exposed to different growth factors was studied by Western blot and by immunohistochemical analysis using a FN EDA-specific monoclonal antibody. Both cell supernatants and homogenates were examined. Results:Expression of FN EDA was detected in cultures of fetal RPE cells stimulated with either transforming growth factor-ß (TGFß) or vascular endothelial growth factor (VEGF). Other growth factors tested (hepatocyte-, fibroblast-, and platelet-derived growth factors) had no effect on FN EDA expression. Conclusion:The results of this study suggest that FN EDA expression might be up-regulated in disorders in which TGFß and VEGF are expressed and may therefore contribute to the pathogenesis of these disorders.

Keywords: 567 retinal pigment epithelium • 423 growth factors/growth factor receptors • 507 pathology: human