Estrogen receptor (ER)-mediated transcriptional regulation of the human corticotropin-releasing hormone-binding protein promoter: differential effects of ERalpha and ERbeta.
CRH-binding protein (CRH-BP) regulates activation of the hypothalamic-pituitary-adrenal (HPA) axis by binding and inhibiting CRH. We investigated for the first time transcriptional regulation of the human CRH-BP promoter using transient transfections. Estrogen receptors (ERs) contributed to ligand-independent constitutive activation of the promoter, whereas in the presence of estradiol ERalpha induced and ERbeta repressed promoter activity in a dose-dependent manner. TNFalpha inhibited promoter induction by ERalpha in the absence and presence of estradiol. Three ERE half-sites in the CRH-BP promoter bound ERalpha and ERbeta in an EMSA, and disruption of ERE half-sites by site-directed mutagenesis abolished ligand-independent induction by ERalpha and ERbeta and promoter enhancement by estradiol-activated ERalpha. Repression by estradiol/ERbeta was unaffected by disruption of ERE half-sites, activating protein 1, cAMP response element, GATA, or nuclear factor kappaB sites, and reversed to promoter induction by estrogen antagonists, tamoxifen and ICI 182,780, suggesting corepressor involvement. In hypothalamic GT1-7 cells, Western blotting demonstrated rapid induction of endogenous CRH-BP expression by estradiol-bound ER, which was inhibited by TNFalpha. We propose a model in which ERs maintain basal CRH-BP expression in pituitary and neurosecretory cells, whereas in the presence of ERalpha estrogen enhances CRH-BP transcription, causing down-regulation of the HPA axis, and nuclear factor kappaB-activating cytokines activate the HPA axis by inhibiting ERalpha.
van de Stolpe
Anja
A
Hubrecht Laboratory, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands. anja@niob.knaw.nl
Slycke
Annika J
AJ
Reinders
Marjolein O
MO
Zomer
Anna W M
AW
Goodenough
Sharon
S
Behl
Christian
C
Seasholtz
Audrey F
AF
van der Saag
Paul T
PT
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D017124:Conserved Sequence / Q000235:genetics; D004958:Estradiol / Q000494:pharmacology / Q000502:physiology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D047629:Estrogen Receptor beta / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D009154:Mutation / Q000235:genetics; D009489:Neurosecretion / Q000235:genetics / Q000502:physiology; D010902:Pituitary Gland / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics*; D020218:Response Elements / Q000187:drug effects / Q000235:genetics; D013629:Tamoxifen / Q000494:pharmacology; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology / Q000502:physiology
D002352:Carrier Proteins; D004965:Estrogen Antagonists; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D014409:Tumor Necrosis Factor-alpha; D013629:Tamoxifen; C067133:corticotropin releasing factor-binding protein; D004958:Estradiol