title: Inhibin alpha gene expression in human trophoblasts is regulated by interactions between TFAP2 and cAMP signaling pathways.
abstract: Inhibin α (Inha) gene expression is regulated, in rat granulosa cells, via a cyclic 3',5'-adenosine monophosphate (AMP)-response element (CRE) found in a region of the promoter that is homologous to the human INHA promoter. We previously found that during in vitro cytotrophoblast differentiation, human INHA gene expression was regulated by TFAP2A via association with an AP-2 site located upstream of this CRE. The aim of this study was to evaluate if the human INHA gene was also regulated by cAMP in trophoblasts, and to investigate the possible crosstalk between TFAP2 and cAMP signaling pathways in the regulation of INHA gene expression. Treatment with cAMP or forskolin increased INHA mRNA expression by 7- and 2-fold in primary cytotrophoblasts and choriocarcinoma-derived BeWo cells, respectively. Treatment with the protein kinase A inhibitor H-89 reduced forskolin-induced luciferase activity by ∼40% in BeWo cells transfected with an INHA promoter-driven luciferase reporter vector. TFAP2 overexpression increased basal luciferase activity, whereas the dominant repressor KCREB abolished it. Surprisingly, mutation of the CRE also eliminated the TFAP2-induced transcription, although TFAP2 overexpression was still able to increase forskolin-induced luciferase activity when the AP-2 binding site, but not the CRE site, was mutated. Thus, INHA gene expression is upregulated by cAMP via CRE in human trophoblasts, and TFAP2 regulates this expression by interacting with CRE.
authors.affiliation: Département d'obstétrique, Institut de recherche expérimentale et clinique (IREC), Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Christophe L
authors.initials: CL
authors.lastname: Depoix
authors.forename: Frédéric
authors.initials: F
authors.lastname: Debiève
authors.forename: Corinne
authors.initials: C
authors.lastname: Hubinont
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007265:Inhibins / Q000378:metabolism*; D008156:Luciferases; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D013045:Species Specificity; D050656:Transcription Factor AP-2 / Q000378:metabolism*; D014327:Trophoblasts / Q000378:metabolism*
chemical_list: D017931:DNA Primers; C493673:TFAP2A protein, human; D050656:Transcription Factor AP-2; C094377:inhibin-alpha subunit; D007265:Inhibins; D000242:Cyclic AMP; D008156:Luciferases