LEDGF: survival of embryonic chick retinal photoreceptor cells.

PURPOSE Lens epithelium-derived growth factor (LEDGF) is a novel adhesive, survival, and growth factor for lens epithelial cells, keratinocytes, fibroblasts, and cos7 cells. In the presence of LEDGF, these cells acquire resistance to environmental stresses, and in the absence of LEDGF they die. The effects of LEDGF on survival of embryonic chick retinal photoreceptor cells under serum starvation and heat stress were studied. METHODS The expression pattern of LEDGF in embryonic chick retinal photoreceptor cells was investigated with protein blot analysis and immunohistochemistry using antibodies (Abs) to LEDGF. Retinal cells were cultured in serum-free medium for up to 6 days in the presence of varying amounts of LEDGF at 37 degrees or 41 degrees C. The photoreceptor cells were immunostained with Abs to arrestin and counted to evaluate the photoreceptor cell viability. Heat shock proteins in the cultured cells were quantified by protein blot analysis with Ab probes and semiquantitative reverse transcription-polymerase chain reaction analysis. RESULTS LEDGF was found predominantly in the nucleus of neuroretinal cells, including photoreceptor cells. In the presence of LEDGF, photoreceptor cells manifested increased resistance to serum starvation and thermal stress and survived for a longer period. The levels of heat shock protein 90 were elevated in those cells. Most retinal cells died in the absence of LEDGF. CONCLUSIONS LEDGF enhanced survival of retinal photoreceptor cells under serum starvation and heat stress. Thus, LEDGF has a potency to enhance survival of neuronal cell types against environmental stresses, and it may be applicable as a therapeutic agent for those cells.