Iron overload-modulated nuclear factor kappa-B activation in human endometrial stromal cells as a mechanism postulated in endometriosis pathogenesis

ObjectiveTo evaluate the effect of iron overload on nuclear factor kappa-B (NF-κB) activation in human endometrial stromal cells (ESCs).DesignExperimental study.SettingUniversity hospital research laboratory.Patient(s)Ten healthy women.Intervention(s)Isolated ESCs from endometrial biopsies were incubated with 50 μM FeSO4 or vehicle. The NF-κB inhibitor [5-(p-fluorophenyl)-2-ureido] thiophene-3-carboxamide (TPCA-1), which inhibits IKKβ, the kinase of IκBα (inhibitory protein of NF-κB), was used to prevent iron overload-stimulated NF-κB changes in ESCs.Main Outcome Measure(s)NF-κB activation was assessed by p65:DNA-binding activity immunodetection assay. IκBα, p65, and intercellular adhesion molecule (ICAM)-1 proteins expression was evaluated by Western blots. ESC soluble ICAM (sICAM)-1 secretion was measured by ELISA using conditioned medium.Result(s)Iron overload increased p65:DNA-binding activity and decreased IκBα and p65 cytoplasmic expression in ESCs after 30 minutes of incubation as compared with the basal condition. ESC ICAM-1 expression and sICAM-1 secretion were higher after 24 hours of iron overload treatment than in the absence of treatment. TPCA-1 prevented the iron overload-induced increase of p65:DNA binding and IκBα degradation.Conclusion(s)Iron overload activates IKKβ in ESCs, stimulating the NF-κB pathway and increasing ICAM-1 expression and sICAM-1 secretion. These results suggest that iron overload induces a proendometriotic phenotype on healthy ESCs, which could participate in endometriosis pathogenesis and development.