Downregulation of differentiation specific gene expression by oxidative stress in ARPE-19 cells

PURPOSE. To investigate how the differentiation of ARPE-19 cells affects th e relative expression of the FGFR genes in response to oxidative stress. METHODS. After differentiation in vitro, APRE-19 cells were treated with t- butyl hydroperoxide (tBH) or hydrogen peroxide (H2O2) to induce oxidative s tress. Viability and reactive oxygen intermediate (ROI) production were mea sured using standard assays. The mRNA expression of FGFR1, FGFR2, cellular retinaldehyde-binding protein (CRALBP), RPE65, and heme oxygenase-1 (HO-1) were measured by Northern blot analysis as a function of treatment with tBH and H2O2. RESULTS. ARPE-19 cells were viable at all tBH concentrations tested but sho wed progressive loss of viability at concentrations greater than 300 muM H2 O2. Differentiated ARPE-19 cells treated with tBH or H2O2 resulted in upreg ulation of the HO-1 and FGFR1 transcripts. The expression of RPE-differenti ated specific genes, including FGFR2, CRALBP, and RPE65 mRNAs, was downregu lated with tBH or H2O2 treatment. CONCLUSIONS. Oxidative stress in differentiated ARPE-19 cells alters the ex pression of FGFR1, FGFR2, CRALBP, and RPE65 toward levels characteristic of the undifferentiated state. If similar changes take place in vivo, these e vents could alter the proliferative potential, viability, and even the func tion of the RPE.