Endometrial miR-543 Is Downregulated During the Implantation Window in Women With Endometriosis-Related Infertility.

BACKGROUND: Differentially expressed microRNAs (miRNAs) and their target mRNAs may lead to alterations in normal physiological status of the tissues and initiate pathological processes. The aim of this study was to investigate the expression of the most relevant miRNAs in the eutopic endometrial tissue during the window of implantation in women with endometriosis-related infertility.

METHODS: In the study, 76 infertile women with a regular menstrual cycle were recruited from the Center for Reproductive Medicine, Peking University Third Hospital between January 2014 and June 2016. We performed a combined messenger RNA and miRNA microarray and bioinformatics analysis of eutopic endometrium in 6 women with and without endometriosis-related infertility at the time of implantation window. Quantitative real-time polymerase chain reaction arrays were utilized to examine the expression levels of selected miRNAs (from 35 patients with endometriosis and 35 disease-free individuals at different menstrual stages).

RESULTS: Five differentially expressed miRNAs (miR-142-5p, miR-146a-5p, miR-1281, miR-940, and miR-4634) were significantly upregulated, whereas miR-543 was significantly downregulated in the eutopic endometrium during the window of implantation in patients with endometriosis. Further analysis showed that miR-543 was significantly upregulated at the peri-implantation phase compared with that at proliferative phase in the endometrium of disease-free patients ( P < .05). However, the expression level of miR-543 was significantly decreased in patients with endometriosis ( P < .05), especially downregulated at the window of implantation phase ( P < .05).

CONCLUSIONS: miR-543 plays an important role during embryo implantation process and is associated with endometrial receptivity. Downregulation of miR-543 may affect embryo implantation, resulting in the pathogenesis of endometriosis-related infertility.