Deficiency in DGCR8-dependent canonical microRNAs causes infertility due to multiple abnormalities during uterine development in mice.

Yeon Sun Kim,Seung Chel Yang,Seok-Ho Hong,Youngsok Choi,Hye-Ryun Kim,Dong Ryul Lee,John P Lydon,Haengseok Song,Mira Park,Hyongbum Kim,Francesco J Demayo,Hyunjung J Lim,Jung Ah Yoon

doi:10.1038/srep20242

Abstract

DGCR8 is an RNA-binding protein that interacts with DROSHA to produce pre-microRNA in the nucleus, while DICER generates not only mature microRNA, but also endogenous small interfering RNAs in the cytoplasm. Here, we produced Dgcr8 conditional knock-out mice using progesterone receptor (PR)-Cre (Dgcr8d/d) and demonstrated that canonical microRNAs dependent on the DROSHA-DGCR8 complex are required for uterine development as well as female fertility in mice. Adult Dgcr8d/d females neither underwent regular reproductive cycles nor produced pups, whereas administration of exogenous gonadotropins induced normal ovulation in these mice. Interestingly, immune cells associated with acute inflammation aberrantly infiltrated into reproductive organs of pregnant Dgcr8d/d mice. Regarding uterine development, multiple uterine abnormalities were noticeable at 4 weeks of age when PR is significantly increased, and the severity of these deformities increased over time. Gland formation and myometrial layers were significantly reduced, and the stromal cell compartment did not expand and became atrophic during uterine development in these mice. These results were consistent with aberrantly reduced stromal cell proliferation and completely failed decidualization. Collectively, we suggest that DGCR8-dependent canonical microRNAs are essential for uterine development and physiological processes such as proper immune modulation, reproductive cycle, and steroid hormone responsiveness in mice.

Highlights

Mouse models with conditional deletions of microRNA processing factor(s) have provided evidence for their critical roles in various aspects of mammalian development and stem cell biology[5,6,7,8]
Realtime reverse transcription-PCR (RT-PCR) results showed that expression levels of Dgcr[8] at postnatal day (PND) 3 were already comparable to those at PND 28 while progesterone receptor (PR) expression is very low at PND 0 and 3 (Fig. 1a,b)
To understand whether microRNA processing is influenced in the uterus by ovarian steroid hormones, estrogen (E2) and progesterone (P4), we examined expression profiles of Dgcr[8] and other factors involved in microRNA biogenesis in uteri of ovariectomized mice exposed to E2 and/or P4 at various time points

Summary

Introduction

Mouse models with conditional deletions of microRNA processing factor(s) have provided evidence for their critical roles in various aspects of mammalian development and stem cell biology[5,6,7,8]. Dicer conditional knockout mice by progesterone receptor (PR)-Cre (Dicerflox/flox;PRcre/+) showed more severe reproductive phenotypes than those observed in Dicerflox/flox;Amhr2cre/+ mice[12]. These results strongly suggest that spatiotemporal modes of CRE provide diverse reproductive phenotypes that could be affected by microRNAs. To precisely delineate the functions of microRNAs, especially canonical microRNAs, in female reproductive tracts, mouse models with conditional deletion(s) of Dicer, and other gene(s) involved in microRNA biogenesis are unquestionably warranted. We generated Dgcr[8] conditional knockout mice by PR-Cre and demonstrated that Dgcr8-dependent canonical microRNAs are critical for uterine morphogenesis and physiological actions of steroid hormones in female reproductive tracts suitable for embryo implantation in mice

Methods

Results

Conclusion