NEUROTROPHIC FACTORS, CYTOKINES AND STRESS INCREASE EXPRESSION OF BASIC FIBROBLAST GROWTH-FACTOR IN RETINAL PIGMENTED EPITHELIAL-CELLS

Basic fibroblast growth factor (bFGF) and FGF receptors have been loca lized to photoreceptors and retinal pigmented epithelium (RPE), but th e function of bFGF in adult retina and RPE is unknown. Exogenous bFGF has a neuroprotective effect in retina and brain and its expression is increased in some neurons in response to cytokines or stress. In this study, we investigated the effect of light, other types of stress, ne urotrophic factors, and cytokines on bFGF levels in cultured human RPE . Some agents that protect photoreceptors from the damaging effects of constant light, including brain-derived neurotrophic factor (BDNF), c iliary neurotrophic factor, and interleukin-1 beta, increase bFGF mRNA levels in RPE cells. Intense light and exposure to oxidizing agents a lso increase bFGF mRNA levels in RPE cells and cycloheximide blocks th e increase, An increase in bFGF protein levels was demonstrated by ELI SA in RPE cell supernatants after incubation with BDNF or exposure tt, intense light or oxidizing agents. These data indicate that bFGF is m odulated in RPE cells by stress and by agents that provide protection from stress and support the hypothesis that bFGF functions as a surviv al factor in the outer retina. (C) 1997 Academic Press Limited.