Estrogen receptor-α and -β regulate the human corticotropin-releasing hormone gene through similar pathways

Corticotropin-releasing hormone (CRH) plays a central role in controlling stress response. In this study, we aimed to identify the regulatory effect of estrogen receptor (ER) on CRH and the underlying mechanism. We investigated the regulation of CRH mRNA in the BE(2)-C cell line, a human neuroblastoma cell line which express endogenous CRH. Quantitative reverse transcriptase-polymerase chain reactions showed that in the presence of estradiol overexpressing ER a or ER 1 in BE(2)-C cells increased the transcription of CRH. Chromatin immunoprecipitation assays in this cell line also showed that both ER alpha and ER beta can be recruited to the CRH promoter with the treatment of estradiol. However, electrophoretic mobility shift assays did not show direct binding between estrogen receptors and two estrogen response elements (ERE) half sites in the CRH promoter. To clarify the regulatory mechanism, site-directed mutagenesis and reporter gene assay in the CHO cell line were used. When the ERE half sites and the cAMP regulatory element (CRE) in the CRH promoter were disrupted, ER-mediated up-regulation of CRH promoter activity reduced. Between the two ERE half sites studied, the -316 ERE half site contributed more to the constitutive CRH expression induced by ER. In summary, our results confirm the stimulation of ER alpha and ER beta on CRH expression and demonstrate the important roles of the ERE half sites and CRE for the action of ER alpha and ER beta. (c) 2008 Elsevier B.V. All rights reserved.