microRNAs and Endometrial Pathophysiology

MiR-148a-3p may contribute to flawed decidualization in recurrent implantation failure by modulating HOXC8

PURPOSE

To evaluate whether miR-148a-3p overexpression is associated with disrupted decidualization of recurrent implantation failure (RIF).

METHODS

Endometrial miRNA and mRNA expression profiles during the implantation window derived from women with and without RIF were identified using microarray and RT-qPCR. Immortalized human endometrial stromal cells (HESCs) were cultured for proliferation and in vitro decidualization assays after enhancing miR-148a-3p expression or inhibiting putative target gene homeobox C8 (HOXC8) expression. RT-qPCR, western blot, and luciferase reporter assays were used to confirm the relationship between miR-148a-3p and HOXC8 gene.

RESULTS

MiR-148a-3p was significantly upregulated in RIF endometrial tissues. Forced expression of miR-148a-3p notably attenuated HESC in vitro decidualization. Mechanistic studies revealed that miR-148a-3p directly bounds to the HOXC8 3' untranslated region (3'UTR) and suppressed HOXC8 expressions in both mRNA and protein levels. Further investigations demonstrated that inhibition of HOXC8 in HESCs induced similar effects on decidual process as those induced by miR-148a-3p overexpression.

CONCLUSION

Taken together, our findings suggested that elevated miR-148a-3p might account for flawed decidualization in RIF by negatively regulating HOXC8, raising the possibility that miR-148a-3p might be a novel therapeutic target in RIF.

Progesterone Resistance in Endometriosis Is Modulated by the Altered Expression of MicroRNA-29c and FKBP4

CONTEXT

Endometriosis results in aberrant gene expression in the eutopic endometrium (EuE) and subsequent progesterone resistance. MicroRNA (miR) microarray data in a baboon model of endometriosis showed an increased expression of miR-29c.

OBJECTIVES

To explore the role of miR-29c in progesterone resistance in a subset of women with endometriosis.

DESIGN

MiR-29c expression was analyzed in the endometrium of baboons and women with or without endometriosis. The role in progesterone resistance and decidualization was analyzed by transfecting human uterine fibroblast cells with miR-29c.

PATIENTS

Subjects diagnosed with deep infiltrative endometriosis (DIE) by transvaginal ultrasound with bowel preparation underwent surgical excision of endometriosis. Eutopic secretory endometrium was collected pre- and postoperatively. Women with normal EuE and without DIE served as controls.

RESULTS

Quantitative reverse transcription polymerase chain reaction demonstrated that miR-29c expression increased, while the transcript levels of its target, FK506-binding protein 4 (FKBP4), decreased in the EuE of baboons following the induction of endometriosis. FKBP4 messenger RNA and decidual markers were statistically significantly decreased in decidualized human uterine fibroblast cells transfected with a miR-29c mimic compared with controls. Human data corroborated our baboon data and demonstrated higher expression of miR-29c in endometriosis EuE compared with normal EuE. MiR-29c was significantly decreased in endometriosis EuE postoperatively compared with preoperative tissues, and FKBP4 showed an inverse trend following radical laparoscopic resection surgery.

CONCLUSIONS

We demonstrate that miR-29c expression is increased in EuE of baboons and women with endometriosis, which might contribute to a compromised progesterone response by diminishing the levels of FKBP4. Resection of DIE is likely to reverse the progesterone resistance associated with endometriosis in women.