Inverse regulation of the interferon-γ receptor and its signaling in human endometrial stromal cells during decidualization

Objective To investigate whether human endometrial stromal cells (ESCs) express the interferon- γ -receptor (IFN- γ R) and whether the process of decidualization or human chorionic gonadotropin (hCG) regulate the IFN- γ R and its signaling pathway. Design In vitro experiment. Setting Research laboratory at a medical university center. Patient(s) Premenopausal women undergoing hysterectomy for benign reasons. Intervention(s) Isolation and incubation of ESCs from hysterectomy specimens with 17β-estradiol, progesterone, recombinant hCG, and IFN- γ as well as an IFN- γ R-blocking antibody. Main Outcome Measure(s) We analyzed IFN- γ R and the phosphorylation of signal transducer and activator of transcription 1 (STAT-1) by flow cytometry. We measured IFN- γ R and interferon response factor 1 (IRF-1) mRNA using semiquantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR). Result(s) The IFN-γR is up-regulated in human ESCs during decidualization without affecting the phosphorylation of STAT-1. Stimulation of IRF-1 by IFN-γ is reduced in decidualized ESCs. We found that hCG neither regulates the IFN-γR nor its signaling pathway. Conclusion(s) These results show an inverse regulation of the IFN-γR and its signaling response via STAT-1 and IRF-1 in human ESCs during decidualization. The early embryonic signal hCG has no effect on this process. This mechanism may finely modulate the reactivity of ESCs to IFN-γ-mediated signals from immune cells at the implantation site.