Lijun Ding

MicroRNA-181a Suppresses Mouse Granulosa Cell Proliferation by Targeting Activin Receptor IIA

Activin, a member of the transforming growth factor-β superfamily, promotes the growth of preantral follicles and the proliferation of granulosa cells. However, little is known about the role of microRNAs in activin-mediated granulosa cell proliferation. Here, we reported a dose- and time-dependent suppression of microRNA-181a (miR-181a) expression by activin A in mouse granulosa cells (mGC). Overexpression of miR-181a in mGC suppressed activin receptor IIA (acvr2a) expression by binding to its 3′-untranslated region (3′-UTR), resulting in down-regulation of cyclin D2 and proliferating cell nuclear antigen expression, leading to inhibition of the cellular proliferation, while overexpression of acvr2a attenuated the suppressive effect of miR-181a on mGC proliferation. Consistent with the inhibition of acvr2a expression, miR-181a prevented the phosphorylation of the activin intracellular signal transducer, mothers against decapentaplegic homolog 2 (Smad2), leading to the inactivation of activin signaling pathway. Interestingly, we found that miR-181a expression decreased in ovaries of mice at age of 8, 12, and 21 days, as compared with that in ovaries of 3-day old mice, and its level was reduced in preantral and antral follicles of mice compared with that in primary ones. Moreover, the level of miR-181a in the blood of patients with premature ovarian failure was significantly increased compared with that in normal females. This study identifies an interplay between miR-181a and acvr2a, and reveals an important role of miR-181a in regulating granulosa cell proliferation and ovarian follicle development.

MicroRNA-133b stimulates ovarian estradiol synthesis by targeting Foxl2.

Forkhead L2 (Foxl2) is expressed in ovarian granulosa cells and participates in steroidogenesis by transcriptionally regulating target genes such as steroidogenic acute regulatory protein (StAR) and CYP19A1. In this study, a direct link between microRNA‐133b (miR‐133b) and Foxl2‐mediated estradiol release in granulosa cells was established. miR‐133b was involved in follicle‐stimulating hormone (FSH)‐induced estrogen production. Luciferase assays confirmed that miR‐133b was bound to the 3′ untranslated region (3′UTR) of Foxl2 mRNA. Consistent with this finding, miR‐133b overexpression reduced the Foxl2 levels. Furthermore, miR‐133b inhibited Foxl2 binding to the StAR and CYP19A1 promoter sequences. These results demonstrate that miR‐133b down‐regulates Foxl2 expression in granulosa cells by directly targeting the 3′UTR, thus inhibiting the Foxl2‐mediated transcriptional repression of StAR and CYP19A1to promote estradiol production.

Transplantation of bone marrow mesenchymal stem cells on collagen scaffolds for the functional regeneration of injured rat uterus.

Serious injuries of endometrium in women of reproductive age are often followed by uterine scar formation and a lack of functional endometrium predisposing to infertility or miscarriage. Bone marrow-derived mesenchymal stem cells (BM-MSCs) have shown great promise in clinical applications. In the present study, BM-MSCs loaded onto degradable collagen membranes were constructed. Collagen membranes provided 3-dimmensional architecture for the attachment, growth and migration of rat BM-MSCs and did not impair the expression of the stemness genes. We then investigated the effect of collagen/BM-MSCs constructs in the healing of severe uterine injury in rats (partial full thickness uterine excision). At four weeks after the transplantation of collagen/BM-MSCs constructs, BM-MSCs were mainly located to the basal membrane of regenerative endometrium. The wounded tissue adjacent to collagen/BM-MSCs constructs expressed higher level of bFGF, IGF-1, TGFβ1 and VEGF than the corresponding tissue in rats receiving collagen construct alone or in spontaneous regeneration group. Moreover, the collagen/BM-MSCs system increased proliferative abilities of uterine endometrial and muscular cells, facilitated microvasculature regeneration, and restored the ability of endometrium to receive the embryo and support its development to a viable stage. Our findings indicate that BM-MSCs may support uterine tissue regeneration.

FSH acts on the proliferation of type A spermatogonia via Nur77 that increases GDNF expression in the Sertoli cells.

The molecular mechanism responsible for the regulation of GDNF in Sertoli cells remains largely unknown. In the present study, FSH induced the expression of Nur77 and GDNF in mouse testis tissue and human fetal Sertoli cells. Moreover, FSH increased the number of A spermatogonia co‐cultured with Sertoli cells. In the additional assays, Nur77 was observed to directly regulate GDNF transcription. Furthermore, overexpression of Nur77 and siRNA‐mediated knockdown of Nur77 affected levels of GDNF mRNA and protein in primary human fetal Sertoli cells. These results indicate that FSH‐induced Nur77 regulates the expression of GDNF in Sertoli cells to stimulate the proliferation of A spermatogonia in vitro.

Orphan nuclear receptor Nur77 regulates androgen receptor gene expression in mouse ovary.

The androgen receptor (AR) is a nuclear receptor that is expressed in growing follicles and involved in folliculogenesis and follicle growth. The orphan nuclear receptor, Nur77, also has an important role in steroid signaling and follicle maturation. We hypothesized that AR levels and androgen signaling through AR are regulated by Nur77 in the ovary. In the ovaries of Nur77 knockout mice (n = 5), real-time PCR results showed that the mRNA levels of AR and an androgen signaling target gene, Kitl, were decreased by 35% and 24%, respectively, relative to wild-type mice (n = 5), which suggested transcriptional regulation of AR by Nur77 in vivo. In cultured mouse granulosa cells and a steroidogenic human ovarian granulosa-like tumor cell line, KGN, mRNA and protein expression levels of AR were increased by overexpressing Nur77 but decreased by knocking down endogenous Nur77. Consistent with increased AR expression, chromatin immunoprecipitation showed that Nur77 bound to the NGFI-B response element (NBRE) in the AR promoter sequence. AR promoter activity was stimulated by Nur77 in HEK293T cells and attenuated in Nur77 knockout mouse granulosa cells (luciferase assay). Overexpression of Nur77 enhanced the androgenic induction of Kitl (200 nM; 48h), while knockout of Nur77 attenuated this induction. These results demonstrate that AR is regulated by Nur77 in the ovaries, and they suggest that the participation of Nur77 in androgen signaling may be essential for normal follicular development.

MicroRNA-181a is involved in the regulation of human endometrial stromal cell decidualization by inhibiting Krüppel-like factor 12

BackgroundThe transformation of endometrium into decidua is essential for normal implantation of the blastocyst. However, the post-transcriptional regulation and the miRNAs involved in decidualization remain poorly understood. Here, we examined microRNA-181a (miR-181a) expression in decidualized human endometrial stromal cell (hESC). In addition, we investigated the functional effect of miR-181a on hESC decidualization in vitro.MethodsQuantitative real-time PCR (qRT-PCR) was used to detect the profile of miR-181a in decidualized hESC. qRT-PCR, enzyme-linked fluorescent assay, and immunofluorescence assay were performed to investigate decidualization marker genes’ expression after enhancing or inhibition of miR-181a expression in hESC. Luciferase reporter assay, western blotting, qRT-PCR, and immunofluorescence assay were carried out to identify the relationship between miR-181a and Krüppel-like factor 12 (KLF12).ResultsmiR-181a expression levels increased dramatically in hESC treated with 8-Br-cAMP and MPA. Increased miR-181a expression promoted hESC decidualization-related gene expression and morphological transformation; conversely, inhibition of miR-181a expression compromised hESC decidualization in vitro. Further analysis confirmed that miR-181a interacted with the 3′ untranslated region of the transcription factor KLF12 and down-regulated KLF12 at the transcriptional and translational levels. KLF12 overexpression abolished miR-181a-induced decidualization.ConclusionsOur findings suggest that miR-181a plays a functionally important role in human endometrial stromal cell decidualization in vitro by inhibiting KLF12.

CYR61 Modulates the Vascular Endothelial Growth Factor C Expression of Decidual NK Cells Via PI3K/AKT Pathway

Citation Zhang X, Ding L, Diao Z, Yan G, Sun H, Hu Y. CYR61 modulates the vascular endothelial growth factor C expression of decidual NK cells via PI3K/AKT pathway. Am J Reprod Immunol 2012; 67: 216–223

Tripterygium Glycosides Impairs the Proliferation of Granulosa Cells and Decreases the Reproductive Outcomes in Female Rats

This study was carried out to investigate the impact of tripterygium glycosides (TGs) on ovarian function of female rats in vitro and in vivo. In vitro studies showed that TG induced cells decrease at G1 phase and inhibited cell proliferation in rat granulosa cells. In vivo, female rats were intragastrically administered with TG at the dose of 60 mg/kg/day for consecutive 50 days. TG caused a prolonged estrous cycle, and a significant reduction in ovarian index, serum E2 level, and numbers of secondary and antral follicles (p < 0.05) in these rats. A significant reduction of viable embryos was demonstrated in TG-treated female rats after mating (p < 0.01). Further, we observed observed the reduced expression level of TGF-β1 after TG treatment in vitro and in vivo. Moreover, the expression of Smad2 and AKT was also decreased after TG treatment. These results suggest that TG can impair ovarian function through Smads-mediated TGF-β1 signal pathway.

miR-181a increases FoxO1 acetylation and promotes granulosa cell apoptosis via SIRT1 downregulation

Oxidative stress impairs follicular development by inducing granulosa cell (GC) apoptosis, which involves enhancement of the transcriptional activity of the pro-apoptotic factor Forkhead box O1 (FoxO1). However, the mechanism by which oxidative stress promotes FoxO1 activity is still unclear. Here, we found that miR-181a was upregulated in hydrogen peroxide (H2O2)-treated GCs and a 3-nitropropionic acid (NP)-induced in vivo model of ovarian oxidative stress. miR-181a overexpression promoted GC apoptosis, whereas knockdown of endogenous miR-181a blocked H2O2-induced cell apoptosis. Moreover, we identified that Sirtuin 1 (SIRT1), a deacetylase that suppresses FoxO1 acetylation in GCs, was downregulated by miR-181a and reversed the promoting effects of H2O2 and miR-181a on FoxO1 acetylation and GC apoptosis. Importantly, decreased miR-181a expression in the in vivo ovarian oxidative stress model inhibited apoptosis by upregulating SIRT1 expression and FoxO1 deacetylation. Together, our results suggest that miR-181a mediates oxidative stress-induced FoxO1 acetylation and GC apoptosis by targeting SIRT1 both in vitro and in vivo.

miR-133b Reverses the Hydrosalpinx-induced Impairment of Embryo Attachment Through Down-regulation of SGK1

CONTEXT Hydrosalpinx impairs endometrial receptivity and embryo implantation. However, the exact underlying mechanism remains elusive. OBJECTIVE This study aimed to explore how an miR-133b-mediated mechanism controls endometrial receptivity and embryo attachment in the endometrium of women with hydrosalpinx. DESIGN, SETTING, PATIENTS, AND INTERVENTIONS Ishikawa cells were treated with hydrosalpinx fluid (HF) from infertile patients and cultured for in vitro analysis. The attachment rates of BeWo spheroids and mouse embryos to Ishikawa cells were assayed. PRIMARY OUTCOME MEASURE miR-133b, serum and glucocorticoid-regulated kinase 1 (SGK1), and homeobox A10 (HOXA10) expression levels were evaluated by quantitative real-time PCR and Western blot assays. RESULTS The expression of miR-133b and HOXA10 was significantly down-regulated, whereas the miR-133b target gene SGK1 was up-regulated in mid-secretory endometrial tissues of women with hydrosalpinx and in HF-treated Ishikawa cells. Moreover, hydrosalpinx inhibited miR-133b expression through the activation of nuclear factor κB/p65, and SGK1 decreased miR-133b-induced HOXA10 expression by phosphorylating cAMP responsive element binding protein in Ishikawa cells. Our results also showed that miR-133b and HOXA10 contributed to BeWo spheroid adhesiveness, whereas SGK1 inhibited BeWo spheroid attachment to Ishikawa cells. Importantly, miR-133b overexpression reversed the HF-mediated impairment of embryo attachment in vitro. CONCLUSIONS miR-133b directly targets SGK1 to reverse the hydrosalpinx-induced down-regulation of HOXA10 and to attenuate the impairment of embryo attachment in vitro.