Erythropoietin gene expression by hydrogen peroxide

We examined the effect of H2O2 on the regulation of the human erythropoietin (Epo) gene through the GATA sequence in the Epo promoter in Hep3B cells. The addition of exogenous H2O2 in Hep3B cells inhibited hypoxia-induced Epo production of mRNA as assessed by competitive polymerase chain reaction (PCR) and protein by EIA. Likewise, menadione, which increased production of endogenous H2O2, inhibited hypoxia-induced Epo production in Hep3B cells. Furthermore, the expression of the human GATA (hGATA) transcription factor was increased dose-dependently by the addition of H2O2 or menadione in Hep3B cells as assessed by gel mobility shift assay. We concluded that H2O2 inhibits Epo gene expression, because it enhanced the expression of the hGATA transcription factor. Our findings support the hypothesis that GATA is a transcription factor for the Epo gene acting through the oxygen sensor.