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Background: Human embryo implantation is regulated by estradiol (E2), progesterone and locally produced mediators including interleukin-1beta (IL-1beta). Interactions between the estrogen receptor (ER) and NF kappa B (NFkappaB) signalling pathways have been reported in other systems but have not been detailed in human endometrium.Methods and Results: Real-time PCR showed that mRNA for the p65 and p105 NFkappaB subunits is maximally expressed in endometrium from the putative implantation window. Both subunits are localized in the endometrial epithelium throughout the menstrual cycle. Reporter assays for estrogen response element (ERE) activity were used to examine functional interactions between ER and NFkappaB in telomerase immortalized endometrial epithelial cells (TERT-EEC). E2 and IL-1beta treatment of TERT-EECs enhances ERE activity by a NFkappaB and ER dependent mechanism; this effect could be mediated by ERalpha or ERbeta. E2 and IL-1beta also positively interact to increase endogenous gene expression of prostaglandin E synthase and c-myc. This is a gene-dependent action as there is no additive effect on cyclin D1 or progesterone receptor expression.Conclusion: In summary, we have established that NFkappaB signalling proteins are expressed in normal endometrium and report that IL-1beta can enhance the actions of E2 in a cell line derived from healthy endometrium. This mechanism may allow IL-1beta, possibly from the developing embryo, to modulate the function of the endometrial epithelium to promote successful implantation, for example by regulating prostaglandin production. Aberrations in the interaction between the ER and NFkappaB signalling pathways may have a negative impact on implantation contributing to pathologies such as early pregnancy loss and infertility. [ABSTRACT FROM AUTHOR]

Background: The role of the innate immune system in tubal implantation remains undefined. This study compared expression of two key mediators of innate immunity, secretory leukocyte protease inhibitor (SLPI) and elafin, in the uterine decidua of women with intrauterine and tubal pregnancies.Methods: Uterine decidua was collected from women (18-45 years) undergoing surgical termination of pregnancy (n = 7), surgical management of spontaneous abortion (n = 6) and tubal pregnancy (n = 10). Using quantitative RT-PCR and immunohistochemistry, mRNA and protein expression patterns of SLPI and elafin were compared.Results: Relative SLPI mRNA expression was significantly higher in decidua of women with tubal pregnancy (12.37 +/- 2.66) compared with spontaneous abortion (5.09 +/- 2.22, P < 0.0185). There was no difference demonstrated in elafin mRNA expression. SLPI and elafin protein expression were demonstrated in the decidual leukocyte populations and epithelium. There was no obvious qualitative difference in levels of SLPI and elafin protein expression or their distribution in the uterine decidua of women with termination of pregnancy, spontaneous abortion or tubal pregnancy.Conclusions: Herein we demonstrate novel differences in gene expression of uterine decidua of tubal pregnancy compared with spontaneous abortion thereby contributing further to current knowledge of mechanisms involved in extrauterine implantation. The altered expression of SLPI may be a consequence of, or predispose to, tubal pregnancy. [ABSTRACT FROM AUTHOR]