Contrary effects of cytokines on mRNAs of cell cycle- and ECM-related proteins in hRPE cells in vitro

Abstract

Purpose. Retinal pigment epithelial (RPE) cells play a pivotal role in the pathogenesis of proliferative vitreoretinopathy (PVR). As a result of a breakdown of the blood-retina barrier, growth factors obtain access to the subretinal space and stimulate several retinal cell types. The aim of the present study was to analyze the effect of several growth factors on the proliferation of human (h)RPE cells, and on the mRNA expression of transcription factors, cell cycle proteins, and extracellular matrix (ECM) proteins. Methods. hRPE cells were incubated in the presence of TGF-ß1, TGF-ß2, PDGF, VEGF, or bFGF for 24–72 h. Cell proliferation was assessed by determinating BrdU incorporation. Changes in mRNA expression of c- fos, c- myc, PCNA, FEN1, Ki67, collagen III, and collagen IV were investigated by ribonuclease protection assay (RPA). Results. RPE cell proliferation was significantly increased by exposure to PDGF and bFGF for 48 h, and was decreased by application of TGF-ß1 and TGF-ß2 for 48 and 72 h. All the tested growth factors significantly elevated the amounts of c- fos mRNA (after 1 h) and of c- myc mRNA (after 24 h). PDGF and bFGF up-regulated the expression of Ki67 mRNA, and down-regulated that of collagen III and collagen IV mRNA after 24 h. TGF-ß1 and TGF-ß2 decreased the expression of Ki67 mRNA, and increased that of collagen III and collagen IV mRNA. Conclusion. Our results show that distinct cytokines may induce contrary effects with respect to proliferation of, and ECM formation by, hRPE cells in vitro. This knowledge may be useful for the development of improved therapeutic approaches.