HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Estrogen and Estrogen Receptor-α-Mediated Transrepression of Bile Salt Export Pump.

Abstract
Among diseases unique to pregnancy, intrahepatic cholestasis of pregnancy is the most prevalent disorder with elevated serum bile acid levels. We have previously shown that estrogen 17β-estradiol (E2) transrepresses bile salt export pump (BSEP) through an interaction between estrogen receptor (ER)-α and farnesoid X receptor (FXR) and transrepression of BSEP by E2/ERα is an etiological contributing factor to intrahepatic cholestasis of pregnancy. Currently the mechanistic insights into such transrepression are not fully understood. In this study, the dynamics of coregulator recruitment to BSEP promoter after FXR activation and E2 treatment were established with quantitative chromatin immunoprecipitation assays. Coactivator peroxisome proliferator-activated receptor-γ coactivator-1 was predominantly recruited to the BSEP promoter upon FXR activation, and its recruitment was decreased by E2 treatment. Meanwhile, recruitment of nuclear receptor corepressor was markedly increased upon E2 treatment. Functional evaluation of ERα and ERβ chimeras revealed that domains AC of ERα are the determinants for ERα-specific transrepression on BSEP. Further studies with various truncated ERα proteins identified the domains in ERα responsible for ligand-dependent and ligand-independent transrepression. Truncated ERα-AD exhibited potent ligand-independent transrepressive activity, whereas ERα-CF was fully capable of transrepressing BSEP ligand dependently in vitro in Huh 7 cells and in vivo in mice. Both ERα-AD and ERα-CF proteins were associated with FXR in the coimmunoprecipitation assays. In conclusion, E2 repressed BSEP expression through diminishing peroxisome proliferator-activated receptor-γ coactivator-1 recruitment with a concurrent increase in nuclear receptor corepressor recruitment to the BSEP promoter. Domains AD and CF in ERα mediated ligand-independent and ligand-dependent transrepression on BSEP, respectively, through interacting with FXR.
AuthorsYuan Chen, Alex Vasilenko, Xiulong Song, Leila Valanejad, Ruchi Verma, Sangmin You, Bingfang Yan, Stephanie Shiffka, Leeza Hargreaves, Christina Nadolny, Ruitang Deng
JournalMolecular endocrinology (Baltimore, Md.) (Mol Endocrinol) Vol. 29 Issue 4 Pg. 613-26 (Apr 2015) ISSN: 1944-9917 [Electronic] United States
PMID25675114 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
Chemical References
  • ATP Binding Cassette Transporter, Subfamily B, Member 11
  • ATP-Binding Cassette Transporters
  • Abcb11 protein, mouse
  • Estrogen Receptor alpha
  • Receptors, Cytoplasmic and Nuclear
  • Transcription Factors
  • peroxisome-proliferator-activated receptor-gamma coactivator-1
  • farnesoid X-activated receptor
  • Estradiol
Topics
  • ATP Binding Cassette Transporter, Subfamily B, Member 11
  • ATP-Binding Cassette Transporters (genetics, metabolism)
  • Animals
  • Cell Line, Tumor
  • Estradiol (pharmacology)
  • Estrogen Receptor alpha (genetics, metabolism)
  • Humans
  • Mice
  • Promoter Regions, Genetic
  • Receptors, Cytoplasmic and Nuclear (genetics, metabolism)
  • Transcription Factors (genetics, metabolism)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: