Expression of HOXA11 in the mid-luteal endometrium from women with endometriosis-associated infertility

BACKGROUND: A decrease in HOXA11 expression in eutopic mid-secretory endometrium has been found in women with endometriosis-associated infertility. METHODS: Using Real-time quantitative PCR (RQ-PCR) and western blotting analysis we studied the HOXA11 transcript and protein levels in mid-luteal eutopic endometrium from eighteen infertile women with minimal endometriosis, sixteen healthy fertile women and sixteen infertile women with fallopian tubal occlusion from the Polish population. We also evaluated transcript levels of DNA methyltransferases DNMT1, DNMT3A and DNMT3B in these groups of women. RESULTS: There were significantly lower levels of HOXA11 transcripts (p = 0.003, p = 0.041) and protein (p = 0.004, p = 0.001) in women with endometriosis as compared to fertile women and infertile women with tubal occlusion. Moreover, we found significantly higher methylation levels of the CpG region in the first exon of HOXA11 in infertile women with endometriosis compared with fertile women (p < 0.001) and infertile women with tubal occlusion (p < 0.001). We also observed significantly increased levels of DNMT3A transcript in women with endometriosis than fertile women (p = 0.044) and infertile women with tubal occlusion (p = 0.047). However, we did not observe significant differences in DNMT1 and DNMT3B transcript levels between these investigated groups of women. CONCLUSIONS: We confirmed that reduced HOXA11 expression may contribute to endometriosis-associated infertility. Moreover, we found that DNA hypermethylation can be one of the possible molecular mechanisms causing a decrease in HOXA11 expression in the eutopic mid-secretory endometrium in infertile women with endometriosis

Expression of HOXA-10 and HOXA-11 in the endometria of women with idiopathic infertility

In fertile women, HOXA-10 and HOXA-11 expression rises during the luteal phase, with the peak occurring during the implantation window, and stays at a high level until the end of the cycle. We evaluated the transcript and protein levels of HOXA-10 and HOXA-11 in the endometria of patients with idiopathic infertility (n = 15) and control patients (n = 10). The amounts of mRNA were determined by reverse transcription and real-time quantitative PCR. The protein levels were evaluated by Western blotting analysis. Using immunohistochemical techniques, we compared the localization of HOXA-10 and HOXA-11 proteins in the implantation window between the study and control groups. We observed statistically significantly decreased HOXA-10 and HOXA-11 transcript levels (p = 0.003, p = 0.012 respectively) in infertile patients compared to controls. There was no significant decrease in HOXA-10 protein levels between these groups (p = 0.074). However, we observed a significantly higher level of HOXA-11 protein in the endometria of infertile patients compared to controls (p = 0.015). HOXA-10 and HOXA-11 proteins were localized in the nuclei of the endometrial stromal cells. Immunohistochemical analyses did not reveal differences between amounts of HOXA-10 and HOXA-11 protein levels in infertility and control groups. Our results suggest that HOXA-10 and HOXA-11 gene expression in the endometrium during the implantation window may not be altered in patients with idiopathic infertility. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 1, pp. 111&#8211;118