Glucocorticoid inhibition of granulocyte macrophage-colony-stimulating factor from T cells is independent of control by nuclear factor-kappaB and conserved lymphokine element 0.
Release of granulocyte macrophage-colony-stimulating factor (GM-CSF) from T cells is important in the differentiation, maturation, and survival of inflammatory cells. Here the induction of GM-CSF expression from T cells was dependent on transcription and translation and was prevented by dexamethasone. In primary human CD3(+) T cells, up to 3.3 kb of human GM-CSF promoter was strongly activated by PMA + PHA. Mutations in either the -85/-76 nuclear factor (NF)-kappaB site or the activator protein-1 region in the -54/-31 conserved lymphokine element 0 (CLE0) site substantially reduced promoter activity. Both GM-CSF promoter and NF-kappaB-dependent constructs were unresponsive to dexamethasone whereas the release of GM-CSF was potently repressed. Analysis of GM-CSF mRNA and protein expression at various time points and the effect of adding dexamethasone after the stimulus revealed the existence of potent mechanisms of inhibition acting at a translational level. The expression of tristetraproline and HuR, proteins that bind the AU-rich element in the GM-CSF 3'-untranslated region was unaffected by dexamethasone and overall AU-rich element binding activity was unaltered. Taken together our data support an important role for the NF-kappaB and CLE0 sites in the transcriptional control of GM-CSF expression in primary human T cells and suggest that post-transcriptional/translational mechanisms are key mediators of glucocorticoid-dependent repression.
Bergmann
Martin W
MW
Department of Thoracic Medicine, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom.
Staples
Karl J
KJ
Smith
Susan J
SJ
Barnes
Peter J
PJ
Newton
Robert
R
D020413:3' Untranslated Regions; D000954:Antigens, Surface / Q000187:drug effects / Q000378:metabolism; D001483:Base Sequence; D002478:Cells, Cultured; D017124:Conserved Sequence; D004268:DNA-Binding Proteins; D003907:Dexamethasone / Q000494:pharmacology; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D005938:Glucocorticoids / Q000494:pharmacology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D006207:Half-Life; D006801:Humans; D017874:Immediate-Early Proteins / Q000187:drug effects / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D008222:Lymphokines / Q000235:genetics*; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D051816:Tristetraprolin
D020413:3' Untranslated Regions; D000954:Antigens, Surface; D004268:DNA-Binding Proteins; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D005938:Glucocorticoids; D017874:Immediate-Early Proteins; D008222:Lymphokines; D016328:NF-kappa B; D010835:Phytohemagglutinins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D051816:Tristetraprolin; C497552:ZFP36 protein, human; D003907:Dexamethasone; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013755:Tetradecanoylphorbol Acetate