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, fib roblasts, and cos7 cells. In the presence of LEDGF, these cells acquire res istance to environmental stresses, and in the absence of LEDGF they die. Th e effects of LEDGF on survival of embryonic chick retinal photoreceptor cel ls under serum starvation and heat stress were studied. METHODS. The expression pattern of LEDGF in embryonic chick retinal photore ceptor cells was investigated with protein blot analysis and immunohistoche mistry using antibodies (Abs) to LEDGF. Retinal cells were cultured in seru m-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 w ith Abs to arrestin and counted to evaluate the photoreceptor cell viabilit y. Heat shock proteins in the cultured cells were quantified by protein blo t analysis with Ab probes and semiquantitative reverse transcription-polyme rase chain reaction analysis. RESULTS. LEDGF was found predominantly in the nucleus of neuroretinal cells , including photoreceptor cells. In the presence of LEDGF, photoreceptor ce lls 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 s erum starvation and heat stress. Thus, LEDGF has a potency to enhance survi val of neuronal cell types against environmental stresses, and it may be ap plicable as a therapeutic agent for those cells.