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

PURPOSE. To investigate how the differentiation of ARPE-19 cells affects the 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 stress. Viability and reactive oxygen intermediate (ROI) production were measured 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 showed progressive loss of viability at concentrations greater than 300 μM H₂O₂. Differentiated ARPE-19 cells treated with tBH or H₂O₂ resulted in upregulation of the HO-1 and FGFR1 transcripts. The expression of RPE-differentiated specific genes, including FGFR2, CRALBP, and RPE65 mRNAs, was downregulated with tBH or H₂O₂ treatment. CONCLUSIONS. Oxidative stress in differentiated ARPE-19 cells alters the expression of FGFR1, FGFR2, CRALBP, and RPE65 toward levels characteristic of the undifferentiated state. If similar changes take place in vivo, these events could alter the proliferative potential, viability, and even the function of the RPE.