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Vitreous treatment of retinal pigment epithelial cells results in decreased expression of FGF-2.

PURPOSE
Changes in gene expression were investigated after treatment of cultured human retinal pigment epithelial (RPE) cells with vitreous. This may have implications for proliferative diseases such as proliferative vitreoretinopathy.


METHODS
Cells were cultured in the presence or absence of human vitreous, and gene expression was examined using the differential display polymerase chain reaction technique. Differentially expressed RNAs were cloned, screened for differential expression, and sequenced. The expression of one of these RNAs (that for fibroblast growth factor [FGF]-2/basic FGF) was examined by in situ hybridization and ribonuclease protection assays. The level of FGF-2 protein was examined by immunoblot analysis. The effects of adding FGF-2 to cells cultured in the presence of vitreous were examined.


RESULTS
Treatment of low passage human RPE cells with 25% vitreous resulted in the epithelial-to-fibroblast-like morphologic changes reported by others and in the decreased expression of FGF-2 mRNA and FGF-2 protein. Addition of FGF-2 to cultures at the same time as addition of vitreous prevented some of the effects of vitreous on these cells.


CONCLUSIONS
Vitreous treatment of RPE cells in culture results in decreased expression of FGF-2 mRNA and protein. Because supplementation of FGF-2 prevents some of the vitreous-mediated effects, this may indicate that modulation of FGF-2 levels by the vitreous may play an important role in the phenotypic changes seen in RPE cells exposed to vitreous.