Carlos Patricio Alvarado-Díaz1, Marco Tulio Núñez2, Luigi Devoto1, Reinaldo González-Ramos3. 1. Maternal and Child Research Institute, Department of Obstetrics and Gynecology, Faculty of Medicine, San Borja Arriarán Hospital, University of Chile, Santiago, Chile. 2. Cellular Dynamics and Biotechnology Institute, Faculty of Sciences, University of Chile, Santiago, Chile. 3. Maternal and Child Research Institute, Department of Obstetrics and Gynecology, Faculty of Medicine, San Borja Arriarán Hospital, University of Chile, Santiago, Chile. Electronic address: rgonzalezr@med.uchile.cl.
Abstract
OBJECTIVE: To evaluate the effect of iron overload on nuclear factor kappa-B (NF-κB) activation in human endometrial stromal cells (ESCs). DESIGN: Experimental study. SETTING: University hospital research laboratory. PATIENT(S): Ten healthy women. INTERVENTION(S): Isolated ESCs from endometrial biopsies were incubated with 50 μM FeSO(4) 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.
OBJECTIVE: To evaluate the effect of iron overload on nuclear factor kappa-B (NF-κB) activation in human endometrial stromal cells (ESCs). DESIGN: Experimental study. SETTING: University hospital research laboratory. PATIENT(S): Ten healthy women. INTERVENTION(S): Isolated ESCs from endometrial biopsies were incubated with 50 μM FeSO(4) 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.