Successful reversal of ovarian hyperstimulation syndrome in a mouse model by rapamycin, an mTOR pathway inhibitor

Effects of IL-11/IL-11 Receptor Alpha on Proliferation and Steroidogenesis in Ovarian Granulosa Cells of Dairy Cows

Granulosa cells (GCs) are essential for follicular growth, oocyte maturation, and steroidogenesis in the ovaries. Interleukin (IL)-11 is known to play a crucial role in the decidualization of the uterus, however, the expression of the IL-11 system (IL-11, IL-11Rα, and gp130) in the bovine ovary and its exact role in GCs have not been extensively studied. In this study, we identified the IL-11 signaling receptor complex in the bovine ovary and investigated the regulatory effects and underlying mechanism of IL-11Rα on the proliferation and steroidogenesis of GCs. We observed that the IL-11 complex was highly expressed in the GCs of large follicles. IL-11Rα knockdown significantly inhibited GC proliferation by inducing cell cycle arrest at the G1 phase, along with a significant downregulation of proliferating cell nuclear antigen (PCNA) and Cyclin D1 (CCND1) protein, and induced GC apoptosis by significantly upregulating the ratio of BCL-2-associated X protein (BAX) and B-cell lymphoma-2 (BCL-2). In addition, IL-11Rα knockdown attenuated the Janus kinase (JAK) 1-signal transducer and activator of transcription 3 (STAT3) signaling, which is related to cell proliferation and apoptosis. Furthermore, the enzyme-linked immunosorbent assay (ELISA) indicated that IL-11Rα silencing decreased the basal and forskolin (FSK)-stimulated secretions of estradiol and progesterone in GC culture medium concomitantly with a remarkable decrease in cytochrome P450 family 19 subfamily A member 1 (CYP19A1) and steroidogenic acute regulatory protein (StAR). We subsequently determined that this reduction in steroidogenesis was in parallel with the decrease in phosphorylations of protein kinase A (PKA) substrates, cAMP-response element binding protein (CREB), extracellular regulated protein kinase (ERK) 1/2, and p38 mitogen-activated protein kinase (MAPK). Taken together, these data indicate that the effects of IL-11/IL-11Rα on the proliferation and steroidogenesis in bovine GCs is mediated by the JAK1-STAT3, PKA-CREB, p38MAPK, and ERK1/2 signaling pathways. Our findings provide important insights into the local action of the IL-11 system in regulating ovarian function.

EGR1 Promotes Ovarian Hyperstimulation Syndrome Through Upregulation of SOX9 Expression

Angiogenesis is strongly associated with ovarian hyperstimulation syndrome (OHSS) progression. Early growth response protein 1 (EGR1) plays an important role in angiogenesis. This study aimed to investigate the function and mechanism of EGR1 involved in OHSS progression. RNA-sequencing was used to identify differentially expressed genes. In vitro OHSS cell model was induced by treating KGN cells with human chorionic gonadotropin (hCG). In vivo OHSS model was established in mice. The expression levels of EGR1, SOX1, and VEGF were determined by Quantitative Real-Time polymerase chain reaction (qRT-PCR), Western blot, immunofluorescence staining, and immunochemistry assay. The content of VEGF in the culture medium of human granulosa-like tumor cell line (KGN) cells was accessed by the ELISA assay. The regulatory effect of EGR1 on SRY-box transcription factor 9 (SOX9) was addressed by luciferase reporter assay and chromatin immunoprecipitation. The ERG1 and SOX9 levels were significantly upregulated in granulosa cells from OHSS patients and there was a positive association between EGR1 and SOX9 expression. In the ovarian tissues of OHSS mice, the levels of EGR1 and SOX9 were also remarkedly increased. Treatment with hCG elevated the levels of vascular endothelial growth factor (VEGF), EGR1, and SOX9 in KGN cells. Silencing of EGR1 reversed the promoting effect of hCG on VEGF and SOX9 expression in KGN cells. EGR1 transcriptionally regulated SOX9 expression through binding to its promoter. In addition, administration of dopamine decreased hCG-induced VEGF in KGN cells and ameliorated the progression of OHSS in mice, which were companied with decreased EGR1 and SOX9 expression. EGR1 has a promoting effect on OHSS progression and dopamine protects against OHSS through suppression of EGR1/SOX9 cascade. Our findings may provide new targets for the treatment of OHSS.

Frozen embryo transfer in the menstrual cycle after moderate-severe ovarian hyperstimulation syndrome: a retrospective analysis

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a rare but serious complication of controlled ovarian stimulation. Frozen-embryo transfer (ET) is prompted to be performed in the next menstrual cycles after cancellation of fresh-ET after occurrence of OHSS. However, effects of frozen-ET in the second menstrual cycle have never been investigated. Therefore, this study aimed to assess this in the menstrual cycle after OHSS.

METHODS

The OHSS group included 342 women with moderate-severe OHSS who underwent the first frozen-ET in the second menstrual cycle in the First Affiliated Hospital of Anhui Medical University from June 2018 to September 2019. A total of 342 women without OHSS who received frozen-ET in the second menstrual cycle were selected as control group matched by age, body mass index, fertility history, ovulation induction scheme. Uni- and multi-variable conditional logistic regression was used to estimate the association between moderate-severe OHSS and pregnancy outcomes.

RESULTS

There were no significant differences in maternal outcomes (miscarriage, preterm birth and pregnancy complications including gestational diabetes mellitus, pregnancy-induced hypertension, placenta previa, premature rupture of membranes and postpartum hemorrhage) and in neonatal outcome (birth-weight and body length, neonatal congenital diseases and other complications) between the two groups in either uni- or multi-variable models.

CONCLUSIONS

Frozen-ET in the menstrual cycle after OHSS has similar maternal and neonatal outcomes as in women without OHSS. This study indicates that frozen-ET could be performed in the second menstrual cycle in women who recovered from moderate-severe OHSS.

The Effect of Stimulation Protocols (GnRH Agonist vs. Antagonist) on the Activity of mTOR and Hippo Pathways of Ovarian Granulosa Cells and Its Potential Correlation with the Outcomes of In Vitro Fertilization: A Hypothesis

Controlled ovarian hyperstimulation (COH) is essential for the success of in vitro fertilization (IVF). Evidence showing the comparison of different COH protocols remains predominantly of low certainty and derives from unspecified infertile and highly heterogeneous populations. Thus, personalized approaches to examine the response of patients to the various COH protocols need to be investigated. Data from in vitro and animal studies have identified the mechanistic target of rapamycin (mTOR) and Hippo signaling pathways play a key role in follicular homeostasis and oocyte quality. To be specific, current data indicate the controlled activation of mTOR and the controlled inhibition of the Hippo pathway within the ovarian granulosa cells (GC). Both are reported to lead to a nurturing follicular microenvironment, increase oocyte quality, and potentially improve reproductive outcomes. As intracellular markers, phosphorylated/unphosphorylated levels of the pathways’ main downstream mediators could be included among the candidate “personalized” predictors of patients’ response to COH protocols and final IVF outcomes. Based on these hypotheses, we make a preliminary attempt to investigate their validity: We propose a prospective cohort study to compare the levels of certain phosphorylated/unphosphorylated components of the investigated pathways (mTOR, ribosomal protein S6 kinase beta-1 (p70S6K-1), yes-associated protein-1 (YAP-1), and transcriptional coactivator with PDZ-binding motif (TAZ)) within the follicular fluid-isolated GC between women undergoing gonadotropin-releasing hormone (GnRH) antagonist/“short” protocols and those receiving GnRH agonist/“long 21” protocols. A case-control design comparing these levels between women achieving pregnancy and those who did not is further planned. Additional analyses addressing the population’s expected heterogeneity are planned after the completion of the pilot phase, during which 100 participants undergoing IVF are intended to be recruited. At this stage, these hypotheses are solely based on in vitro/animal data, and thus, similar studies on humans in this respect are necessary for the investigation of their potential validity.

Multiple Protocols Combined with Hyperbaric Oxygen Therapy on the Maintenance of Ovarian Function in Patients After Ovarian Cystectomy

Objective

This study aims to explore the effect of adjuvant hyperbaric oxygen therapy on ovarian function after laparoscopic ovarian cystectomy.

Methods

A total of 60 patients with ovarian cysts treated at our hospital from January 2018 to August 2020 were enrolled. According to the different treatment modalities, the patients were divided into the control and observation groups. Patients in both groups underwent laparoscopic ovarian cystectomy with oral administration of Chinese patent medicine Kuntai capsules after surgery. Hyperbaric oxygen therapy was added to patients in the observation group in addition to the treatment in the control group. The anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and antral follicle count (AFC) serum levels were detected in both groups before the operation and at the first and third menstrual cycles postoperatively to evaluate ovarian function.

Results

At the first and third menstrual cycles after surgery, the AMH, E2, and AFC serum levels in the two groups were significantly lower than before surgery, and the FSH and LH serum levels were higher than before surgery. The differences were statistically significant (P < 0.05). After the operation, AMH, E2, and AFC serum levels in the observation group were significantly higher than in the control group. FSH and LH serum levels were significantly lower than in the control group, and the differences were statistically significant (P < 0.05).

Conclusion

For patients undergoing laparoscopic ovarian cystectomy, the adjuvant hyperbaric oxygen therapy could significantly improve the postoperative ovarian reserve function with remarkable effects.

Baicalin improves the functions of granulosa cells and the ovary in aged mice through the mTOR signaling pathway

Background

The mammalian follicle is the basic functional unit of the ovary, and its normal development is required to obtaining oocytes capable of fertilization. As women get older or decline in ovarian function due to certain pathological factors, the growth and development of follicles becomes abnormal, which ultimately leads to infertility and other related female diseases. Kuntai capsules are currently used in clinical practice to improve ovarian function, and they contain the natural compound Baicalin, which is a natural compound with important biological activities. At present, the role and mechanism of Baicalin in the development of ovarian follicles is unclear.

Methods

Human primary granulosa cells collected from follicular fluid, and then cultured and treated with Baicalin or its normal control, assessed for viability, subjected to RT-PCR, western blotting, flow cytometry, and hormone analyses. The estrus cycle and oocytes of CD-1 mice were studied after Baicalin administration and compared with controls. Ovaries were collected from the mice and subjected to hematoxylin-eosin staining and immunohistochemistry analysis.

Results

We showed that Baicalin had a dose-dependent effect on granulosa cells cultured in vitro. A low concentration of Baicalin (for example, 10 μM) helped to maintain the viability of granulosa cells; however, at a concentration exceeding 50 μM, it exerted a toxic effect. A low concentration significantly improved the viability of granulosa cells and inhibited cell apoptosis, which may be related to the resultant upregulation of Bcl-2 expression and downregulation of Bax and Caspase 3. By constructing a hydrogen peroxide-induced cell oxidative stress damage model, we found that Baicalin reversed the cell damage caused by hydrogen peroxide. In addition, Baicalin increased the secretion of estradiol and progesterone by upregulating P450arom and stAR. The results of the in vivo experiment showed that the intragastric administration of Baicalin to aged mice improved the estrous cycle and oocyte quality. Furthermore, we observed that Baicalin enhanced the viability of granulosa cells through the mTOR pathway, which in turn improve ovarian function.

Conclusion

These results indicate that Baicalin could improve the viability of ovarian granulosa cells and the secretion of steroid hormones and thus could help to improve degenerating ovarian function and delay ovarian aging.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-00965-7.

Altered expression of activator proteins that control follicle reserve after ovarian tissue cryopreservation/transplantation and primordial follicle loss prevention by rapamycin

PURPOSE

We investigated whether expression of activator proteins that control follicle reserve and growth change after ovarian tissue vitrification and re-transplantation. Moreover, we assessed whether inhibition of mTOR signaling pathway by rapamycin would protect primordial follicle reserve after ovarian tissue freezing/thawing and re-transplantation.

METHODS

Fresh control, frozen/thawed, fresh-transplanted, frozen/thawed and transplanted, rapamycin/control, rapamycin fresh-transplanted, and rapamycin frozen-thawed and transplanted groups were established in rats. After freezing and thawing process, two ovaries were transplanted into the back muscle of the same rat. After 2 weeks, grafts were harvested, fixed, and embedded into paraffin block. Normal and atretic primordial/growing follicle count was performed in all groups. Ovarian tissues were evaluated for the dynamic expressions of Gdf-9, Bmp-15, KitL, Lif, Fgf-2, and p-s6K using immunohistochemistry, and H-score analyses were done.

RESULTS

Primordial follicle reserve reduced almost 50% after ovarian tissue re-transplantation. Expression of Gdf-9 and Lif increased significantly in primordial and growing follicles in frozen-thawed, fresh-transplanted, and frozen/thawed and transplanted groups, whereas expression of Bmp-15, KitL, and Fgf-2 decreased in primordial follicles. Freezing and thawing of ovarian tissue solely significantly increased p-s6K expression in primordial follicles, and on the other hand, suppression of mTORC1 pathway using rapamycin preserved the primordial follicle pool.

CONCLUSION

Altered expressions of activator proteins that regulate primordial follicle reserve and growth may lead to primordial follicle loss and rapamycin treatment can protect ovarian reserve after ovarian tissue cryopreservation/transplantation.