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.