Integrin-alpha5 mediates epidermal growth factor-induced retinal pigment epithelial cell proliferation and migration.

Proliferation and migration of retinal pigment epithelial (RPE) cells play a crucial role in proliferative vitreoretinopathy (PVR)-related pathology. Cytokines, including EGF, can result in RPE cell activation and cause PVR. In this study, integrin-alpha(5) expression was first studied in PVR membranes by immunofluorescence. Then the effect of EGF on integrin-alpha(5) expression was determined by flow cytometry, Western blot analysis and the reverse-transcription polymerase chain reaction (RT-PCR) in the ARPE-19 cell line. Proliferation and migration of ARPE-19 cells were measured by the methylthiazolyldiphenyl-tetrazolium bromide and Boyden chamber assays. We found that a higher level integrin-alpha(5) was present at the RPE cell surface in PVR compared with normal retina. EGF could dose dependently increase integrin-alpha(5) mRNA and protein levels in vitro. EGF promoted ARPE-19 cell proliferation and migration. Neutralizing integrin-alpha(5) by specific anti-integrin-alpha(5) antibody abolished most of the effects of EGF. The study provided evidence that EGF might influence PVR by promoting integrin-alpha(5) expression and subsequent proliferation and migration of RPE.