Ligand activated relaxin receptor increases the transcription of IGFBP-1 and prolactin in human decidual and endometrial stromal cells.
The aim of this study was to investigate relaxin (RLX) receptor-mediated gene activation in human endometrium. We determined the promoter activities of insulin-like growth factor binding protein-1 (IGFBP-1) and prolactin (PRL) and identified sequence(s) that mediate RLX activated transcription in human decidual cells and endometrial stromal cells. In human decidual cells, the promoter activity of IGFBP-1 was increased significantly in cells incubated with RLX. In endometrial stromal cells, the RLX mediated activation was enhanced only when stromal cells were co-transfected with RLX-receptor (LGR7) expression vector and RLX alone had little effect (Mazella et al., 2004). Deletion and mutation analysis showed that the cAMP regulatory element (CRE, -263 to -259 bp) in the IGFBP-1 promoter was essential for the activation. In addition, RLX increased the phosphorylation of CRE binding protein (CREB to p-CREB) and p-CREB resided in the nucleus, indicating that RLX activates the protein kinase (PKA) system in decidual cells. Gel shift assay showed that nuclear extracts prepared from RLX treated decidual cells increased the binding to the CRE site of the IGFBP-1 promoter. RLX increased the PRL promoter activity mediated through the region containing multiple CCAAT/enhancer-binding proteins (C/EBP) binding sites that have been shown to mediate the PRL gene activation by cAMP analogue (Pohnke et al., 1999). RLX enhanced IGFBP-1 promoter activity was inhibited by cAMP dependent PKA inhibitor, H-89. PRL promoter activity was inhibited by both H-89 and U0126 indicating multiple signalling pathways are activated by RLX in endometrial cells for different target gene activation.
Tang
Meiyi
M
Department of Obstetrics and Gynecology, School of Medicine, State University of New York at Stony Brook, Stony Brook, NY 11794-8091, USA.
Mazella
James
J
Zhu
Hui Hui
HH
Tseng
Linda
L
D000328:Adult; D002070:Butadienes / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D003656:Decidua / Q000166:cytology / Q000378:metabolism*; D004717:Endometrium / Q000166:cytology / Q000378:metabolism*; D005260:Female; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics*; D007546:Isoquinolines / Q000494:pharmacology; D008024:Ligands; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D009154:Mutation; D009570:Nitriles / Q000494:pharmacology; D011257:Pregnancy Proteins / Q000235:genetics*; D011388:Prolactin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D018000:Receptors, Peptide; D017154:Stromal Cells / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D002070:Butadienes; C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; C032231:IGFBP1 protein, human; D018970:Insulin-Like Growth Factor Binding Protein 1; D018969:Insulin-Like Growth Factor Binding Proteins; D007546:Isoquinolines; D008024:Ligands; D008565:Membrane Proteins; D009570:Nitriles; D011257:Pregnancy Proteins; D047428:Protein Kinase Inhibitors; C417543:RXFP1 protein, human; D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; D013449:Sulfonamides; D014157:Transcription Factors; C113580:U 0126; D011388:Prolactin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D048369:MAP Kinase Kinase 1; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide