Lens epithelium-derived growth factor: Increased survival and decreased DNA breakage of human RPE cells induced by oxidative stress

Purpose. Lens epithelium-derived growth factor (LEDGF) has been shown to be a growth and survival factor and to be present in a wide variety of cell t ypes. The purpose of this study was to determine whether LEDGF enhances sur vival of human retinal pigment epithelial (RPE) cells when challenged by ox idative stress or by ultraviolet (UVB) irradiation in a culture system. Methods. Primary RPE cells were cultured in standard Dulbecco's modified Ea gle's medium (DMEM) containing 15% fetal bovine serum. Protein blot analysi s,vith antibodies to LEDGF was used to detect LEDGF in RPE cells. Initially , RPE cells were cultured in the standard medium for 1 day to allow attachm ent to the culture plates and then Cultured in serum-free DMEM, with and wi thout LEDGF, The trypan blue exclusion method was used to test RPE cell via bility. Single-cell electrophoresis was used to evaluate single strand brea ks of genomic DNA after exposure to H2O2 or irradiation by UVB. Results. LEDGF was present in RPE cells, predominantly in the nucleus. RPE cells grew for 1 week and survived for 3 weeks in the presence of LEDGE In the absence of LEDGF, they increased in number for the first week and gradu ally died in the following 2 weeks., LEDGF protected RPE cells against H2O2 exposure and UVB irradiation. DNA damage induced by H2O2 exposure or UVB i rradiation was lower in the presence than in the absence of LEDGF. The expr ession of heat shock protein (Hsp)27 was elevated by LEDGF. Conclusions. LEDGF enhanced survival of RPE cells in culture when challenge d by oxidative stress and UVB irradiation. LEDGF protected DNA from single- strand breakage and upregulated the expression of Hsp27. These results Sugg est that LEDGF may be a potential agent for protecting RPE cells under vari ous stress conditions.