Biosynthesis of nitric oxide activates iron regulatory factor in macrophages.
Biosynthesis of nitric oxide (NO) from L-arginine modulates activity of iron-dependent enzymes, including mitochondrial acontiase, an [Fe-S] protein. We examined the effect of NO on the activity of iron regulatory factor (IRF), a cytoplasmic protein which modulates both ferritin mRNA translation and transferrin receptor mRNA stability by binding to specific mRNA sequences called iron responsive elements (IREs). Murine macrophages were activated with interferon-gamma and lipopolysaccharide to induce NO synthase activity and cultured in the presence or absence of NG-substituted analogues of L-arginine which served as selective inhibitors of NO synthesis. Measurement of the nitrite concentration in the culture medium was taken as an index of NO production. Mitochondria-free cytosols were then prepared and aconitase activity as well as IRE binding activity and induction of IRE binding activity were correlated and depended on NO synthesis after IFN-gamma and/or LPS stimulation. Authentic NO gas as well as the NO-generating compound 3-morpholinosydnonimine (SIN-1) also conversely modulated aconitase and IRE binding activities of purified recombinant IRF. These results provide evidence that endogenously produced NO may modulate the post-transcriptional regulation of genes involved in iron homeostasis and support the hypothesis that the [Fe-S] cluster of IRF mediates iron-dependent regulation.
Drapier
J C
JC
U365 INSERM, Institut Curie, Section de Biologie, Paris, France.
Hirling
H
H
Wietzerbin
J
J
Kaldy
P
P
Kühn
L C
LC
D000154:Aconitate Hydratase / Q000378:metabolism*; D000230:Adenocarcinoma; D000594:Amino Acid Oxidoreductases / Q000096:biosynthesis*; D000818:Animals; D001120:Arginine / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D004790:Enzyme Induction; D007371:Interferon-gamma / Q000494:pharmacology; D035925:Iron-Regulatory Proteins; D007700:Kinetics; D007939:Leukemia L1210; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008325:Mammary Neoplasms, Experimental; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008928:Mitochondria / Q000378:metabolism; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis* / Q000494:pharmacology; D019001:Nitric Oxide Synthase; D009573:Nitrites / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured
D035925:Iron-Regulatory Proteins; D008070:Lipopolysaccharides; D009573:Nitrites; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D009569:Nitric Oxide; C002385:linsidomine; D007371:Interferon-gamma; D001120:Arginine; D008981:Molsidomine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D000154:Aconitate Hydratase