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Tumor necrosis factor alpha and phorbol 12‐myristate‐13‐acetate down‐regulate human 11β‐hydroxysteroid dehydrogenase type 2 through p50/p50 NF‐κB homodimers and Egr‐1
Author(s) -
Kostadinova Radina M.,
Nawrocki Andrea R.,
Frey Felix J.,
Frey Brigitte M.
Publication year - 2005
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.04-2820fje
Subject(s) - transactivation , p50 , microbiology and biotechnology , chromatin immunoprecipitation , tumor necrosis factor alpha , transcription factor , chemistry , electrophoretic mobility shift assay , sp1 transcription factor , mineralocorticoid receptor , biology , receptor , promoter , gene expression , biochemistry , endocrinology , gene
The 11β‐hydroxysteroid dehydrogenase type 2 (11β‐HSD2) regulates access of 11β‐hydroxyglucocorticoids to the mineralocorticoid receptor by reducing the hydroxyl group of these steroids at position 11. Previous cell culture studies revealed that tumor necrosis factor‐α (TNF‐α) down‐regulates 11β‐HSD2 activity. Here, we demonstrate that transgenic mice overexpressing TNF‐α have decreased mRNA abundance and activity of 11β‐HSD2 in kidney tissue, indicating that this effect may occur also in vivo. The analysis of the transcriptional regulation of 11β‐HSD2 by TNF‐α and phorbol 12‐myristate‐13‐acetate (PMA) with in vivo genomic footprinting in human colon SW620 cells revealed stimulus‐dependent protein‐DNA interactions in three promoter regions, κB1, Sp1/Egr‐1I, and Sp1/Egr‐1II. Chromatin immunoprecipitation and electrophoretic mobility shift assays demonstrated the relevance of NF‐κB binding to κB1 and of Egr‐1 binding to Sp1/Egr‐1 sites for the PMA and TNF‐α effect. We observed a temporal switch of binding to κB1 site from active p65/p50 heterodimers to inactive p50/p50 homodimers. TNF‐α or PMA treatment for 24 h resulted in accumulation of p50 and decrease of p65 nuclear proteins. Overexpression of p50 inhibited HSD11B2 promoter activity and overexpression of Egr‐1 inhibited transactivation of the HSD11B2 promoter by p65/p50. In conclusion, TNF‐α and PMA down‐regulate expression and activity of 11β‐HSD2 most likely by a coordinate binding of p50/p50 and Egr‐1 to the HSD11B2 promoter.