Transcriptional activation of the macrophage colony-stimulating factor gene by IL-2 is associated with secretion of bioactive macrophage colony-stimulating factor protein by monocytes and involves activation of the transcription factor NF-kappa B.
Human peripheral blood monocytes (Mo) constitutively display the beta-chain of the receptor for IL-2, whereas expression of the IL-2R alpha-chain is not constitutive but inducible with IL-2. Here we report that binding of human IL-2 to its binding site leads to transcriptional activation of the macrophage CSF (M-CSF) gene in Mo resulting in accumulation of M-CSF mRNA and subsequent release of bioactive M-CSF protein as demonstrated by ELISA and inhibition of IL-2 induced release of an activity-stimulating growth of monocyte-type colonies by a neutralizing anti-M-CSF antibody. Transcriptional activation of the M-CSF gene by IL-2 is preceded by enhanced binding activity of the transcription factor NF-kappa B to its recognition sequence in the 5' regulatory enhancer region of the M-CSF gene. Moreover, using a heterologous promoter (herpes thymidine kinase) construct containing the NF-kappa B consensus sequence, it is shown that NF-kappa B binding by an IL-2-induced monocyte-derived nuclear protein confers reporter gene (human growth hormone) activity. Taken together, our findings indicate that IL-2 induces gene expression of M-CSF in human blood-derived Mo and provide evidence for involvement of NF-kappa B in transcriptional regulation of this gene.
Department of Hematology, Oncology, and Applied Molecular Biology, Free University of Berlin, University Clinic Rudolf, Virchow, Germany.
M A
MA
Brach
C
C
Arnold
M
M
Kiehntopf
H J
HJ
Gruss
F
F
Herrmann
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001483:Base Sequence; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D016173:Macrophage Colony-Stimulating Factor / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D015375:Receptors, Interleukin-2 / Q000032:analysis / Q000502:physiology; D011994:Recombinant Proteins / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D016328:NF-kappa B; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins; D016173:Macrophage Colony-Stimulating Factor