Inhibitory effect of microRNA-34a on retinal pigment epithelial cell proliferation and migration

Abstract

Purpose. Retinal pigment epithelial (RPE) cells play important roles in ophthalmologic diseases such as proliferative vitreoretinopathy, AMD, and diabetic retinopathy. MicroRNA-34a (miR-34a) has been reported to be important in the regulation of cell proliferation, migration, differentiation, and apoptosis. In this study, we explored the effects of miR-34a on RPE cells. Methods. The expression level of miR-34a in subconfluent and postconfluent ARPE-19 cells was investigated with quantitative real-time PCR. MicroRNA mimic and small interfering RNA (siRNA) were transiently transfected into RPE cells. Transfected RPE cells were analyzed with WST-1 proliferation assay, and their migration was analyzed with transwell assay and in vitro scratch study. The expression or activation of target proteins was detected by Western blotting. Results. MicroRNA-34a was significantly downregulated in subconfluent ARPE-19 cells compared with postconfluent cells. Introduction of miR-34a inhibited the proliferation and migratory ability of RPE cells without obvious cell apoptosis. In miR-34a transfected cells, many important proliferation and/or migration related molecules such as c-Met, CDK2, CDK4, CDK6, E2F1, and phosphorylated-Cdc2 (p-Cdc2) were downregulated. Small interfering RNA designed to target c-Met also inhibited the proliferation and migration of RPE cells and downregulated CDK2, CDK6, E2F1, and p-Cdc2. Conclusions. MicroRNA-34a is downregulated in subconfluent RPE cells. MicroRNA-34a can inhibit the proliferation and migration of RPE cells through downregulation of its targets c-Met and other cell cycle-related molecules. Our results indicated that miR-34a is involved in the regulation of RPE cells. © 2013 The Association for Research in Vision and Ophthalmology, Inc.