Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3' Untranslated Regions
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Antigens, Surface / drug effects
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Antigens, Surface / metabolism
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Base Sequence
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Cells, Cultured
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Conserved Sequence
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DNA-Binding Proteins*
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Dexamethasone / pharmacology
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ELAV Proteins
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ELAV-Like Protein 1
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Glucocorticoids / pharmacology*
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Granulocyte-Macrophage Colony-Stimulating Factor / antagonists & inhibitors*
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Granulocyte-Macrophage Colony-Stimulating Factor / genetics
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Granulocyte-Macrophage Colony-Stimulating Factor / metabolism
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Half-Life
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Humans
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Immediate-Early Proteins / drug effects
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Immediate-Early Proteins / metabolism
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Leukocytes, Mononuclear / drug effects
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Leukocytes, Mononuclear / metabolism
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Lymphokines / genetics*
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Molecular Sequence Data
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NF-kappa B / drug effects
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NF-kappa B / metabolism*
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Phytohemagglutinins / pharmacology
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Promoter Regions, Genetic / drug effects
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RNA, Messenger / drug effects
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RNA, Messenger / metabolism
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RNA-Binding Proteins / drug effects
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RNA-Binding Proteins / metabolism
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T-Lymphocytes / drug effects
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T-Lymphocytes / metabolism*
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Tetradecanoylphorbol Acetate / pharmacology
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Time Factors
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Tristetraprolin
Substances
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3' Untranslated Regions
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Antigens, Surface
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DNA-Binding Proteins
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ELAV Proteins
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ELAV-Like Protein 1
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ELAVL1 protein, human
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Glucocorticoids
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Immediate-Early Proteins
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Lymphokines
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NF-kappa B
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Phytohemagglutinins
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RNA, Messenger
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RNA-Binding Proteins
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Tristetraprolin
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ZFP36 protein, human
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Dexamethasone
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Granulocyte-Macrophage Colony-Stimulating Factor
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Tetradecanoylphorbol Acetate