Involvement of nuclear factor-κB in macrophage migration inhibitory factor gene transcription up-regulation induced by interleukin-1β in ectopic endometrial cells

ObjectiveTo investigate the involvement of the nuclear factor (NF)-κB in the interleukin (IL)-1β-mediated macrophage migration inhibitory factor (MIF) gene activation.DesignProspective study.SettingHuman reproduction research laboratory.Patient(s)Nine women with endometriotic lesions.Intervention(s)Endometriotic lesions were obtained during laparoscopic surgery.Main Outcome Measure(s)The MIF protein secretion was analyzed by ELISA, MIF mRNA expression by quantitative real-time polymerase chain reaction (PCR), NF-κB translocation into the nucleus by electrophoresis mobility shift assay, IκB phosphorylation and degradation by Western blot, and human MIF promoter activity by transient cell transfection.Result(s)This study showed a significant dose-dependent increase of MIF protein secretion and mRNA expression, the NF-κB translocation into the nucleus, IκB phosphorylation, IκB degradation, and human MIF promoter activity in endometriotic stromal cells in response to IL-1β. Curcumin (NF-κB inhibitor) significantly inhibited all these IL-1β-mediated effects. Analysis of the activity of deletion constructs of the human MIF promoter and a computer search localized two putative regulatory elements corresponding to NF-κB binding sites at positions -2538/-2528 bp and -1389/-1380 bp.Conclusion(s)This study suggests the involvement of the nuclear transcription factor NF-κB in MIF gene activation in ectopic endometrial cells in response to IL-1β and identifies a possible pathway of endometriosis-associated inflammation and ectopic cell growth.