N-G-monomethyl-L-arginine inhibits erythropoietin gene expression by stimulating GATA-2

N-G-monomethyl-L-arginine (L-NMMA) has been reported to be elevated in urem ic patients. Based on the hypothesis that the pathogenesis of the anemia of renal disease might be due to the perturbation of transcription factors of the erythropoietin (Epo) gene by L-NMMA, the present study was designed to investigate the effect of L-NMMA on Epo gene expression through the GATA t ranscription factor. L-NMMA caused decreased levels of Nc, cyclic guanosine monophosphate (cGMP), and Epo protein in Hep3B cells. L-NAME (analogue of L-NMMA) also inhibited Epo production in anemic mice. Transfection of the E po promoter-luciferase gene into Hep3B cells revealed that L-NMMA inhibited the Epo promoter activity. However, L-NMMA did not inhibit the Epo promote r activity when mutated Epo promoter (GATA to TATA) was transfected, and L- NMMA did not affect the enhancer activity. Electrophoretic mobility shift a ssays demonstrated the stimulation of GATA binding activity by L-NMMA. Howe ver, L-NMMA had no effect on the binding activity of hepatic nuclear factor -4, COUP-TF1, hypoxia-inducing factor-1,or NF-kappa B, Furthermore, cGMP in hibited the L-NMMA-induced GATA binding activity. L-NMMA also increased GAT A-2 messenger RNA expression. These results demonstrate that L-NMMA suppres ses Epo gene expression by upregulation of the GATA transcription factor an d support the hypothesis that L-NMMA is one of the candidate substances tha t underlie the pathogenesis of renal anemia. (C) 2000 by The American Socie ty of Hematology.