Effect of Anti-Müllerian hormone (AMH) and bone morphogenetic protein 15 (BMP-15) on steroidogenesis in primary-cultured human luteinizing granulosa cells through Smad5 signalling

Investigations of the function of AMH in granulosa cells in hens

Anti-mullerian hormone (AMH) plays a crucial role in follicle regulation in mammals by preventing premature primordial follicle activation and restricting follicle development through reduction of FSH sensitivity and inhibition of FSH-induced increase of steroidogenic enzymes. AMH is produced by granulosa cells from growing follicles and expression declines at the time of selection in both mammalian and avian species. The role of AMH in chicken granulosa cells remains unclear, as research is complicated because mammalian AMH is not bioactive in chickens and there is a lack of commercially available chicken AMH. In the current experiments, we used RNA interference to study the role of AMH on markers of follicle development in the presence and absence of FSH. Cultured chicken granulosa cells from 3-5 mm follicles and 6-8 mm follicles, the growing pool from which follicle selection is thought to occur, were used. Transfection with an AMH-specific siRNA significantly reduced AMH mRNA expression in granulosa cells from 3-5 mm and 6-8 mm follicles. Genes of interest were only measured in granulosa cells of 3-5 mm follicles due to low expression of AMH mRNA at the 6-8 mm follicle stage. Knockdown of AMH mRNA did not affect markers of follicle development (follicle stimulating hormone receptor, FSHR; steroidogenic acute regulatory protein, STAR; cytochrome P450 family 11 subfamily A member 1, CYP11A1; bone morphogenetic protein receptor type 2, BMPR2) or FSH responsiveness in granulosa cells from 3-5 mm follicles, indicating that AMH does not regulate follicle development directly by affecting markers of steroidogenesis, FSHR or BMPR2 at this follicle stage in chickens.

In view of ovarian steroidogenesis and luteal construction to explore the effects of Bushen Huoxue recipe in mice of ovarian hyperstimulation

ETHNOPHARMACOLOGICAL RELEVANCE

Bushen Huoxue recipe (BSHXR) is a widely used prescription medicine for treating gynecological diseases. We have previously found that BSHXR can improve the pregnancy outcome of controlled ovarian hyperstimulation (COH) mice by modulating the abnormal high level of progesterone. While the pharmacological mechanism of such therapeutic effect is not clear.

AIM OF THE STUDY

We aimed to investigate the effects of BSHXR on the ovarian steroidogenesis and luteal function in mice undergoing COH.

MATERIALS AND METHODS

A COH mouse model was established via an intraperitoneal injection of 0.4 IU/g pregnant mare serum gonadotropin (PMSG) and 1 IU/g human chorionic gonadotropin (HCG). The histological features of ovaries were observed using hematoxylin-eosin staining. The expression levels of FSHR, LHCGR, and key molecules in ovarian steroidogenesis, including CYP11A1, CYP17A1, CYP19A1, HSD3B1, and StAR, were examined via immunohistochemical staining, western blotting, and RT-qPCR. CD31, VEGFA, and FGF2 levels were assessed to evaluate ovarian vascularization. The protein and mRNA levels of ovarian ERK1/2, p-ERK1/2, MEK1/2, and p-MEK1/2 were also detected using western blotting, RT-qPCR, or immunofluorescence staining.

RESULTS

COH mice had a significantly increased volume and weight of the ovary and number of corpora lutea. In particular, COH exhibited a long-term influence on ovarian FSHR and LHCGR expression, disrupting the levels of CYP11A1, HSD3B1, and CYP17A1, causing poorer luteal angiogenesis. Compared with normal mice, the expression levels of ovarian VEGFA and FGF2 in COH mice were considerably lower on Day 1 after PMSG. On concomitant HCG treatment, both VEGFA and FGF2 expression surged dramatically on ED1 and then declined on ED4 and ED8. Moreover, the expression pattern of MEK1/2-ERK1/2 was almost consistent with that of VEGFA and FGF2. After treatment, BSHXR increased ovarian LHCGR, FSHR, CYP11A1, HSD3B1, and CYP17A1 levels, boosted luteal vascularization, and restored MEK1/2-ERK1/2 signaling in COH mice.

CONCLUSION

BSHXR restored the abnormally high progesterone level by regulating the CYP11A1 and HSD3B1 expression as well as promoted luteal angiogenesis, which was related with LHCGR-MEK1/2-ERK1/2-VEGFA/FGF2 signaling pathway in the ovary. This effect prevented the fluctuation of sex hormones in COH mice and benefited the outcome of pregnancy.

Effect of IGF1 and FSH on the function of granulosa cells from prehierarchal follicles in chickens†

Insulin-like growth factor 1 (IGF1) is an essential regulator of mammalian follicle development and synergizes with follicle-stimulating hormone (FSH) to amplify its effects. In avian preovulatory follicles, IGF1 increases the expression of genes involved in steroidogenesis and progesterone and inhibin A production. The role of IGF1 in prehierarchal follicles has not been well studied in chickens. The aim of this study was to investigate the role of IGF1 in granulosa cells from prehierarchal follicles and to determine whether IGF1 and FSH synergize to promote follicle development. Granulosa cells of 3-5 and 6-8 mm prehierarchal follicles were cultured with IGF1 (0, 10, 100 ng/mL) in the presence or absence of FSH (0, 10 ng/mL). Cell proliferation, expression of genes important in follicle development (FSHR, IGF1R, AMH, STAR, CYP11A1, INHA, and INHBA), and progesterone production were evaluated following treatment. IGF1 treatment alone significantly increased STAR, CYP11A1, and INHBA mRNA expression and cell proliferation in granulosa cells of 6-8 mm follicles. IGF1 and FSH synergized to increase STAR mRNA expression in 6-8 mm follicles. IGF1 and FSH co-treatment were necessary to increase INHA mRNA expression in 6-8 mm follicles. Although IGF1 significantly increased the expression of genes involved in steroidogenesis, progesterone production in granulosa cells of 6-8 mm follicles was not affected. IGF1 did not affect AMH mRNA expression, although FSH significantly decreased AMH expression in granulosa cells of 3-5 mm follicles. These results suggest that IGF1 may act with FSH to promote follicle selection at the prehierarchal follicle stage.

Durable contraception in the female domestic cat using viral-vectored delivery of a feline anti-Müllerian hormone transgene

Eighty percent of the estimated 600 million domestic cats in the world are free-roaming. These cats typically experience suboptimal welfare and inflict high levels of predation on wildlife. Additionally, euthanasia of healthy animals in overpopulated shelters raises ethical considerations. While surgical sterilization is the mainstay of pet population control, there is a need for efficient, safe, and cost-effective permanent contraception alternatives. Herein, we report evidence that a single intramuscular treatment with an adeno-associated viral vector delivering an anti-Müllerian hormone transgene produces long-term contraception in the domestic cat. Treated females are followed for over two years, during which transgene expression, anti-transgene antibodies, and reproductive hormones are monitored. Mating behavior and reproductive success are measured during two mating studies. Here we show that ectopic expression of anti-Müllerian hormone does not impair sex steroids nor estrous cycling, but prevents breeding-induced ovulation, resulting in safe and durable contraception in the female domestic cat.

Key signalling pathways underlying the aetiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine condition characterised by a range of reproductive, endocrine, metabolic and psychological abnormalities. Reports estimate that around 10% of women of reproductive age are affected by PCOS, representing a significant prevalence worldwide, which poses a high economic health burden. As the origin of PCOS remains largely unknown, there is neither a cure nor mechanism-based treatments leaving patient management suboptimal and focused solely on symptomatic treatment. However, if the underlying mechanisms underpinning the development of PCOS were uncovered then this would pave the way for the development of new interventions for PCOS. Recently, there have been significant advances in our understanding of the underlying pathways likely involved in PCOS pathogenesis. Key insights include the potential involvement of androgens, insulin, anti-Müllerian hormone and transforming growth factor beta in the development of PCOS. This review will summarise the significant scientific discoveries on these factors that have enhanced our knowledge of the mechanisms involved in the development of PCOS and discuss the impact these insights may have in shaping the future development of effective strategies for women with PCOS.

Synergistic Regulatory Effect of Inhibin and Anti-Müllerian Hormone on Fertility of Mice

Inhibin (INH) and anti-Müllerian hormone (AMH) are essential in ovarian folliculogenesis and play an inhibitory role in mammalian fertility. However, the interactive effect of INH and AMH on the animal reproduction remains unknown. This study aimed to determine the possible interaction and synergy between INH and AMH in steroidogenesis by primary granulosa cells, and investigate their synergistic effect on fertility in mice. In in vitro granulosa cell culture system, we found that the treatment of either INHA or AMH had no significant effect on basal estradiol and progesterone production, whereas both significantly attenuated FSH-induced steroid hormone secretion. Importantly, combined treatment with INHA and AMH showed additive inhibitory effect on FSH-induced estradiol and progesterone production, accompanying a significant downregulation in the expression of FSH-stimulated CYP19A1, HSD3B, CYP11A1, StAR transcripts. The interrelationship of INH and AMH combinations was further investigated through active immune neutralization strategy. Female mice were immunized against INH and AMH eukaryotic expression plasmids, and the litter size was recorded after successfully mating. We observed that both INH and AMH plasmids were able to induce either anti-AMH or anti-INH antibodies in the immunized mice. In comparison with the control group, co-immunization with INH and AMH plasmids induced higher levels of estradiol, resulting in more litter size. Moreover, there was no significant difference on the offspring's weight between each group. Collectively, the results of the present study suggest that INH and AMH have synergistic effect in regulating steroidogenesis and the litter size in mice.

Anti-Müllerian Hormone Negatively Regulates Osteoclast Differentiation by Suppressing the Receptor Activator of Nuclear Factor-κB Ligand Pathway

Background

Multiple members of the transforming growth factor-β (TGF-β) superfamily have well-established roles in bone homeostasis. Anti-Müllerian hormone (AMH) is a member of TGF-β superfamily of glycoproteins that is responsible for the regression of fetal Müllerian ducts and the transcription inhibition of gonadal steroidogenic enzymes. However, the involvement of AMH in bone remodeling is unknown. Therefore, we investigated whether AMH has an effect on bone cells as other TGF-β superfamily members do.

Methods

To identify the roles of AMH in bone cells, we administered AMH during osteoblast and osteoclast differentiation, cultured the cells, and then stained the cultured cells with Alizarin red and tartrate-resistant acid phosphatase, respectively. We analyzed the expression of osteoblast- or osteoclast-related genes using real-time polymerase chain reaction and western blot.

Results

AMH does not affect bone morphogenetic protein 2-mediated osteoblast differentiation but inhibits receptor activator of nuclear factor-κB (NF-κB) ligand-induced osteoclast differentiation. The inhibitory effect of AMH on osteoclast differentiation is mediated by IκB-NF-κB signaling.

Conclusions

AMH negatively regulates osteoclast differentiation without affecting osteoblast differentiation.

Translational Physiology of Anti-Müllerian Hormone: Clinical Applications in Female Fertility Preservation and Cancer Treatment

Background

Whilst the ability of AMH to induce the regression of the Müllerian ducts in the male fetus is well appreciated, AMH has additional biological actions in relation to steroid biosynthesis and ovarian follicle dynamics. An understanding of the physiology of AMH illuminates the potential therapeutic utility of AMH to protect the ovarian reserve during chemotherapy and in the treatment of female malignancies. The translation of the biological actions of AMH into clinical applications is an emerging focus of research, with promising preliminary results.

Objective and Rationale

Studies indicate AMH restrains primordial follicle development, thus administration of AMH during chemotherapy may protect the ovarian reserve by preventing the mass activation of primordial follicles. As AMH induces regression of tissues expressing the AMH receptor (AMHRII), administration of AMH may inhibit growth of malignancies expressing AMHR II. This review evaluates the biological actions of AMH in females and appraises human clinical applications.

Search Methods

A comprehensive search of the Medline and EMBASE databases seeking articles related to the physiological functions and therapeutic applications of AMH was conducted in July 2021. The search was limited to studies published in English.

Outcomes

AMH regulates primordial follicle recruitment and moderates sex steroid production through the inhibition of transcription of enzymes in the steroid biosynthetic pathway, primarily aromatase and 17α-hydroxylase/17,20-lyase. Preliminary data indicates that administration of AMH to mice during chemotherapy conveys a degree of protection to the ovarian reserve. Administration of AMH at the time of ovarian tissue grafting has the potential to restrain uncontrolled primordial follicle growth during revascularization. Numerous studies demonstrate AMH induced regression of AMHR II expressing malignancies. As this action occurs via a different mechanism to traditional chemotherapeutic agents, AMH has the capacity to inhibit proliferation of chemo-resistant ovarian cancer cells and cancer stem cells.

Wider Implications

To date, AMH has not been administered to humans. Data identified in this review suggests administration of AMH would be safe and well tolerated. Administration of AMH during chemotherapy may provide a synchronistic benefit to women with an AMHR II expressing malignancy, protecting the ovarian reserve whilst the cancer is treated by dual mechanisms.

Anti-Müllerian Hormone Accelerates Pathological Process of Insulin Resistance in Polycystic Ovary Syndrome Patients

Insulin resistance (IR) is one of the most common features of polycystic ovary syndrome (PCOS), which is related to obesity. Whether increased anti-Müllerian hormone (AMH) levels in PCOS are involved in the pathogenesis of insulin resistance remains unclear. We investigated serum levels of leptin and AMH along with basic clinical and metabolic parameters in 114 PCOS patients and 181 non-PCOS women. PCOS patients presented higher fasting blood glucose, insulin concentrations and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) in addition to body mass index (BMI), lipids profiles and hormone levels. HOMA-IR showed a positive correlation with BMI, AMH, leptin, and low-density lipoprotein-cholesterol (LDL-c) levels. Interestingly, AMH is strongly positively correlated with HOMA-IR and insulin concentrations for 1st and 2nd hours of glucose treatment after fasting. Among PCOS women with BMI≥25 kg/m², high AMH level group showed an increased HOMA-IR when compared to normal AMH level. However, among PCOS women with normal BMI, women with high AMH presented an elevated fasting insulin levels but not HOMA-IR when compared to normal AMH group. In vitro treatment of isolated islet cells with high concentration of leptin (200 ng/ml) or high leptin plus high concentration of AMH (1 ng/ml) significantly enhanced insulin secretion. Importantly, co-treatment of AMH plus leptin upregulates the expression of pro-apoptotic proteins, such as Bax, caspase-3, and caspase-8 after incubating with a high level of glucose. These results suggest that AMH may involve in the pathological process of pancreatic β-cells in obese PCOS women.

Pentachloronitrobenzene alters progesterone production and primordial follicle recruitment in cultured granulosa cells and rat ovary†

Pentachloronitrobenzene (PCNB) is an organochlorine fungicide widely used for crop production and has become an environmental concern. Little is known about the effect of PCNB on ovarian steroidogenesis and follicular development. We found that PCNB stimulated Star expression and progesterone production in cultured rat granulosa cells in a dose-dependent manner. PCNB activated mitogen-activated protein kinase (MAPK3/1) extracellulat regulated kinase (ERK1/2), thus inhibition of either protein kinase A (PKA) or MAPK3/1 signaling pathway significantly attenuated progesterone biosynthesis caused by PCNB, suggesting that PCNB induced progesterone production by activating the cyclic adenosine monophosphate (cAMP/PKA) and MAPK3/1 signaling pathways. Further investigation demonstrated that PCNB induced Star expression and altered MAPK3/1 signaling in ovary tissues of immature SD rats treated with PCNB at the dose of 100, 200, or 300 mg/kg by daily gavage for 7 days, while serum progesterone level was dose-dependently decreased. We demonstrated that PCNB exposure accelerated the recruitment of primordial follicles into the growing follicle pool in ovary tissues, accompanied by increased levels of anti-Mullerian hormone (AMH) in both ovary tissues and serum. Taken together, our data demonstrate for the first time that PCNB stimulated Star expression, altered MAPK3/1 signaling and progesterone production in vivo and in vitro, and accelerated follicular development with a concomitant increase in AMH in ovary tissues and serum. Our findings provide novel insight into the toxicity of PCNB to animal ovary function.

Anti-Müllerian hormone as a qualitative marker - or just quantity?

PURPOSE OF REVIEW

In this review, we will summarize research looking into anti-Müllerian hormone (AMH) as a measure of oocyte quality.

RECENT FINDINGS

AMH is a key factor involved in embryogenesis but also in the development of early follicles. Owing to its relatively small inter and intracycle variability, it has become a widely used method of ovarian reserve testing. In the realm of assisted reproductive technology, it has demonstrated a reliable ability to gauge the number of oocytes obtained during an in-vitro fertilization cycle. For these purposes, AMH is a readily measured quantitative tool. However, its qualitative role is as yet undefined.

SUMMARY

Although levels of this hormone have been associated with fertilization, blastulation, implantation, and clinical pregnancy rates, there is no clear link with live-birth rates. Furthermore, AMH levels do not appear to correspond with risk of fetal trisomy. AMH does show significant predictive value for the risk of premature ovarian insufficiency and time to onset of menopause.

Effects of bone morphogenetic protein 15 (BMP15) knockdown on porcine testis morphology and spermatogenesis

Bone morphogenetic protein 15 (BMP15) is a member of the transforming growth factor-β (TGFB) superfamily that plays an essential role in mammalian ovary development, oocyte maturation and litter size. However, little is known regarding the expression pattern and biological function of BMP15 in male gonads. In this study we established, for the first time, a transgenic pig model with BMP15 constitutively knocked down by short hairpin (sh) RNA. The transgenic boars were fertile, but sperm viability was decreased. Further analysis of the TGFB/SMAD pathway and markers of reproductive capacity, namely androgen receptor and protamine 2, failed to identify any differentially expressed genes. These results indicate that, in the pig, the biological function of BMP15 in the development of male gonads is not as crucial as in ovary development. However, the role of BMP15 in sperm viability requires further investigation. This study provides new insights into the role of BMP15 in male pig reproduction.

Influence of pretreatment of insulin on the phosphorylation of extracellular receptor kinase by gonadotropin-releasing hormone and gonadotropins in cultured human granulosa cells

OBJECTIVE

To investigate the influence of pretreatment of insulin on the phosphorylation of ERK1/2 by gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in cultured human granulosa cells.

STUDY DESIGN

Human granulosa cells were collected from 20 women (age: 20-35 years) who underwent controlled ovarian hyperstimulation for in vitro fertilization and embryo transfer at Asan Medical Center (Seoul, South Korea). The presence of the receptors for insulin, GnRH, FSH, and LH in human granulosa cells was identified by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The granulosa cells were treated with 10 nM insulin or 10 nM GnRH for 5 min or 30 min and with 10 nM FSH or 10 nM LH for 24 h or 48 h. The cells were also pretreated with insulin for 30 min prior to treatment with GnRH, FSH, or LH. Western blot analysis was used to analyze ERK1/2 phosphorylation.

RESULTS

RT-PCR showed that the receptors for insulin, GnRH, FSH, and LH were expressed in human granulosa cells. Insulin, GnRH, FSH, and LH could activate ERK1/2 phosphorylation. Pretreatment with insulin inhibited ERK1/2 phosphorylation induced by GnRH and FSH while augmenting ERK1/2 phosphorylation induced by LH.

CONCLUSIONS

Insulin might have a negative effect on GnRH and FSH regulation by attenuating the action of GnRH and FSH in the phosphorylation of ERK1/2 in human granulosa cells. In contrast, insulin might have a positive effect on LH regulation by potentiating the action of LH in the phosphorylation of ERK1/2. Our results showed that insulin is clearly an important regulator of human reproductive function at the ovarian level.

New Anti-Müllerian Hormone Target Genes Involved in Granulosa Cell Survival in Women With Polycystic Ovary Syndrome

PURPOSE

A protective effect of anti-Müllerian hormone (AMH) on follicle atresia was recently demonstrated using long-term treatments, but this effect has never been supported by mechanistic studies. This work aimed to gain an insight into the mechanism of action of AMH on follicle atresia and on how this could account for the increased follicle pool observed in women with polycystic ovary syndrome (PCOS).

METHODS

In vivo and in vitro experiments were performed to study the effects of AMH on follicle atresia and on the proliferation and apoptosis of granulosa cells (GCs). RNA-sequencing was carried out to identify new AMH target genes in GCs. The expression of some of these genes in GCs from control and PCOS women was compared using microfluidic real time quantitative RT-PCR.

RESULTS

A short-term AMH treatment prevented follicle atresia in prepubertal mice. Consistent with this result, AMH inhibited apoptosis and promoted proliferation of different models of GCs. Moreover, integrative biology analyses of 965 AMH target genes identified in 1 of these GC models, confirmed that AMH had initiated a gene expression program favoring cell survival and proliferation. Finally, on 43 genes selected among the most up- and down-regulated AMH targets, 8 were up-regulated in GCs isolated from PCOS women, of which 5 are involved in cell survival.

MAIN CONCLUSIONS

Our results provide for the first time cellular and molecular evidence that AMH protects follicles from atresia by controlling GC survival and suggest that AMH could participate in the increased follicle pool of PCOS patients.

Effect of anti-müllerian hormone on the development and selection of ovarian follicle in hens

To elucidate the role of anti-müllerian hormone (AMH) in regulating the development of ovarian follicles in laying hens, the expressions of follicle-stimulating hormone receptor (FSHR), AMH receptor type 2 (AMHR2), steroidogenic-related genes steroidogenic acute regulatory protein (STAR), cytochrome P450 side-chain cleavage (CYP11A1), and 3β-hydroxysteroid dehydrogenase (HSD3B1) genes were measured from different sized follicles and granulosa cells. The results showed that the expressions of FSHR and AMHR2 genes were higher in small follicles and decreased after follicular selection. Oppositely, the expressions of STAR, CYP11A1, and HSD3B1 were significantly increased after follicular selection. It indicated that AMHR2 might mediate AMH suppression in the stimulating effects of follicle-stimulating hormone (FSH) on steroidogenic-related genes expression. To make sure the effects of AMH in this process, a total of 40 hens were treated (negative control, sham operation, 150 ng AMH/d or 300 ng AMH/d) for 25 d. We analyzed ovarian morphology, progesterone concentration in blood plasma, and the expressions of steroidogenic genes in ovaries and follicles. The AMH300 group had significantly lower weight of ovary and hierarchical follicles. Egg weight and ovary weight in AMH150 group were higher than those of sham operation and AMH300 groups, so did hierarchical follicles weight. The steroidogenic genes expressions showed an increase in ovarian tissue and the largest follicle of AMH150 and AMH300 groups. However, progesterone level in the blood was reduced by AMH injection with different concentrations. To further verify the above results, granulosa cells from 6 to 8 mm follicles were cultured with AMH (0, 5, 10, 20, 40, or 80 ng/mL). The results revealed that excessive AMH (80 ng/mL) exerted an inhibitory effect on progesterone synthesis and the expressions of STAR, CYP11A1, and HSD3B1. However, these genes expressions showed a significant increase in 20 ng/mL AMH-treated group. In summary, AMH inhibited the development of prehierarchical follicles in laying hens. The effects of AMH treatment with different concentrations on follicle development showed the follicle was selected by changing FSH responsiveness of prehierarchical follicles.

Utilizing Calcium Alginate for the Assessment of Bone Morphogenetic Protein 15 Induction Effect on the Differentiation of Mesenchymal Stem Cell Derived from Human Follicular Fluid to Oocyte-Like Structure

Background:

Follicular fluid (FF)-derived mesenchymal stem cells (MSCs) are possible new source of cells in the study of oogenesis and regenerative medicine. Several biomaterials have been used as scaffolds to mimic ovarian tissue stroma. Using good matrix is essential for increasing the cell survival rate, proliferation, and differentiation. However, no study has been performed to investigate the effects of BMP15 and calcium alginate hydrogel on the differentiation potential of FF-derived MSCs to oocyte-like structures (OLSs).

Materials and Methods:

In this work, FF MSCs, which were collected from women in routine in vitro fertilization procedure, were capsulated with 0.5% calcium alginate, and then the encapsulated cells were cultured in medium containing BMP15 for 2 weeks. Trypan blue staining was carried out to determine cell viability. Real-time polymerase chain reaction (PCR) and immunofluorescence (ICC) staining method were performed to characterize the expression of OCT4, Nanog, ZP2, and ZP3 genes and protein. The encapsulation process did not change the morphology and viability of the encapsulated cells.

Results:

Reverse-transcription-PCR and ICC showed that MSCs expressed germ line stem cell markers such as OCT4 and Nanog. After 4 days of culture, OLSs formed and expressed zona pellucida markers. OLSs at least reached 180–230 μm in diameter in the control and BMP15-treated groups. Finally, a reduction in the expression pattern of pluripotency and ZP markers was detected in the encapsulated cells cultured in the BMP15-supplemented medium.

Conclusion:

The three-dimensional alginate culture system seems to be a promising method of getting in vitro differentiation and development of ovarian cells, which could mimic the native ovarian condition.

Bone morphogenetic protein 15 induces differentiation of mesenchymal stem cells derived from human follicular fluid to oocyte-like cell

Follicular fluid (FF) is essential for developing ovarian follicles. Besides the oocytes, FF has abundant undifferentiated somatic cells containing stem cell properties, which are discarded in daily medical procedures. Earlier studies have shown that FF cells could differentiate into primordial germ cells via forming embryoid bodies, which produced oocyte-like cells (OLC). This study aimed at isolating mesenchymal stem cells (MSC) from FF and evaluating the impacts of bone morphogenetic protein 15 (BMP15) on the differentiation of these cells into OLCs. Human FF-derived cells were collected from 78 women in the assisted fertilization program and cultured in human recombinant BMP15 medium for 21 days. Real-time polymerase chain reaction and immunocytochemistry staining characterized MSCs and OLCs. MSCs expressed germline stem cell (GSC) markers, such as OCT4 and Nanog. In the control group, after 15 days, OLCs were formed and expressed zona pellucida markers (ZP2 and ZP3), and reached 20-30 µm in diameter. Ten days after induction with BMP15, round cells developed, and the size of OLCs reached 115 µm. A decrease ranged from 0.04 to 4.5 in the expression of pluripotency and oocyte-specific markers observed in the cells cultured in a BMP15-supplemented medium. FF-derived MSCs have an innate potency to differentiate into OLCs, and BMP15 is effective in promoting the differentiation of these cells, which may give an in vitro model to examine germ cell development.

Growth differentiation factor 9 (gdf9) and bone morphogenetic protein 15 (bmp15) are potential intraovarian regulators of steroidogenesis in Japanese flounder (Paralichthys olivaceus)

Members of transforming growth factor-β (TGF-β) superfamily are vital regulators during the development of fish ovary. However, its intraovarian functions in teleost are still unclear. As members of the TGF-β superfamily, gdf9 and bmp15 are necessary for follicle formation and granulosa cell proliferation. Here in Japanese flounder, quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH) analysis showed that gdf9 and bmp15 were mainly expressed in oogonia and oocytes, whereas weakly expressed in non-ovarian tissues. Overexpression of single gdf9 and the co-overexpression with bmp15 could up-regulate the expression of most steroidogenic genes, while the overexpression of single bmp15 could down-regulate the expression of most steroidogenic genes. These findings demonstrate that single gdf9 and the combination with bmp15 may act as "activator", while single bmp15 may act as "inhibitor" in the process of steroidogenesis in flounder. This was also verified in negative feedback regulation of gdf9 and bmp15 during hormone treatment. High concentration of human chorionic gonadotropin (hCG) could down-regulate gdf9 and up-regulate bmp15, which were beneficial for the homeostasis of hCG hormone. Besides, knockdown of either gdf9 or bmp15 could significantly down-regulate most steroidogenic genes. This indicated that heterodimer of GDF9:BMP15 might be the most bioactive ligand in gonad development of flounder. Taken together, our study provided a novel recognition that gdf9 and bmp15 could regulate steroidogenesis in teleost through mechanism different from that in mammals.

Utilising FGF2, IGF2 and FSH in serum-free protocol for long-term in vitro cultivation of primary human granulosa cells

Human granulosa cells acquired as leftover from IVF treatment can be used to study infertility problems and are a valuable tool in the research of follicle maturation and ovulation. There is a need for more defined and long-term culture protocols for studying the response of granulosa cells upon treatment with selected hormones/chemicals. In the current study, we tested the effect of adding FGF2, IGF2 and FSH into defined basal medium in order to find culture conditions that would support proliferation of cumulus and mural granulosa cells along with the expression of common granulosa cell type markers such as FSHR, AMHR2, LHR and CYP19A1. We found that FGF2, IGF2 together with FSH helped to retain granulosa cell marker expression while supporting cell survival at least for two weeks of culture. The defined serum-free culture conditions for long-term culturing will be valuable in providing new standards in the research of human granulosa cells.

Reparative effects of lycium barbarum polysaccharide on mouse ovarian injuries induced by repeated superovulation

To explore the repair effect of lycium barbarum polysaccharide (LBP) on ovarian injuries induced by repeated superovulation in mice, a model of ovarian injury was established, and ovarian repair was assessed after intragastric administration of LBP. The oocyte quality and blastocyst rates of pronuclear embryos in vitro were observed. The levels of 8-hydroxydeoxyguanosine (8-OHdG) and lipid peroxide (LPO) in ovarian tissue were measured, and ovarian damage was assessed in paraffin sections. The groups with significant injury were selected according to the above observation, mice in the significant injury group were intragastrically administered with LBP (low dose, 25 mg/kg; medium dose, 35 mg/kg; and high dose, 45 mg/kg) for 30 days. The above measurements and anti-Müllerian hormone (AMH) expression were detected in the mouse ovaries and the breeding verification was carried out. Our results showed that repeated superovulation could cause mouse oocyte quality to drop, significant differences started from 4 superovulation events (P < 0.05). The levels of 8-OHdG and LPO in the ovary increased gradually as the number of superovulation events increased, and significant differences were observed after 4-6 superovulations (P < 0.05). The ratios of primordial follicles, primary, tertiary and mature follicles decreased and the ratio of atresia follicles increased as the number of superovulation events increased, especially in 4-6 superovulation groups. Thus, the groups of superovulation 4-6 events were considered as significant injury groups. LBP-medium dose groups significantly improved the number and quantity of oocytes and embryo blastocyst rate (P < 0.05), significantly decreased 8-OHdG and LPO levels in mice ovary (P < 0.05), also improved the ratios of all stages follicles and reduced the rate of atresia follicles, increased the numbers of litter size, live birth, weaning survival, and repaired the expression of AMH in ovary significantly (P < 0.05). In conclusion, the degree of ovarian injury was affected by the number of superovulation. LBP repaired ovarian injuries most likely through scavenging oxidative products 8-OHdG and LPO and increasing AMH protein expression.

Role of Anti-Müllerian Hormone in the Pathogenesis of Polycystic Ovary Syndrome

Besides its interest for diagnosis, the finding of an elevated serum AMH level in PCOS has open major pathophysiological issues. This review addresses the three most important issues: 1- the role of AMH in the disturbed folliculogenesis of PCOS; 2- the role of AMH in the gonadotropin dysregulation of PCOS and 3- the role of AMH in the trans-generational transmission of PCOS. For each of those issues, the clinical and experimental evidences currently available are discussed and pathophysiological hypothesis are proposed.

The transcriptional regulator CBX2 and ovarian function: A whole genome and whole transcriptome approach

The chromobox homolog 2 (CBX2) was found to be important for human testis development, but its role in the human ovary remains elusive. We conducted a genome-wide analysis based on DNA adenine methyltransferase identification (DamID) and RNA sequencing strategies to investigate CBX2 in the human granulosa cells. Functional analysis revealed that CBX2 was upstream of genes contributing to ovarian function like folliculogenesis and steroidogenesis (i.e. ESR1, NRG1, AKR1C1, PTGER2, BMP15, BMP2, FSHR and NTRK1/2). We identified CBX2 regulated genes associated with polycystic ovary syndrome (PCOS) such as TGFβ, MAP3K15 and DKK1, as well as genes implicated in premature ovarian failure (POF) (i.e. POF1B, BMP15 and HOXA13) and the pituitary deficiency (i.e. LHX4 and KISS1). Our study provided an excellent opportunity to identify genes surrounding CBX2 in the ovary and might contribute to the understanding of ovarian physiopathology causing infertility in women.

Anti-Müllerian hormone inhibits luteinizing hormone-induced androstenedione synthesis in porcine theca cells

AMH (Anti-Müllerian Hormone) is involved in the regulation of follicle growth initiation and inhibits FSH-induced aromatase expression and estrogen production in granulosa cells. However, the function of AMH in steroidogenesis by theca cells remains unclear. The aim of this study is to investigate the role of AMH as a regulator of the basal and stimulated steroid production by pig granulosa cells (pGCs) and theca cells (pTCs). PGCs and pTCs were incubated with hormones AMH, LH (luteinizing hormone), FSH (follicle stimulating hormone), individually or in combination. The expression of CYP19A1, HSD3B1, CYP11A1, LHCGR, and CYP17A1 mRNA were evaluated by quantitative reverse transcriptase PCR. In pGCs, 10 ng/mL AMH significantly decreased the FSH-stimulated effect on FSHR and CYP19A1 expression and estradiol production. In pTCs, LH treatment significantly increased the expression of HSD3B1, CYP11A1, LHCGR, and androstenedione or progesterone production (P < 0.05). Additionally, 10 ng/mL AMH also significantly decreased the LH-stimulated effects on the expression of HSD3B1, CYP11A1, CYP17A1, LHCGR and androstenedione production. Transfection with siAMHR2-I abolished the suppressive effects of AMH on LH-induced HSD3B1 expression and androstenedione production. Taken together, these results demonstrate that AMH is involved in FSH induced estradiol production in pGCs and LH induced androstenedione production in pTCs by regulating the steroidogenesis pathway.

FSH inhibits AMH to support ovarian estradiol synthesis in infantile mice

Anti-Müllerian hormone (AMH) regulates ovarian function in cyclic females, notably by preventing premature follicle-stimulating hormone (FSH)-mediated follicular growth and steroidogenesis. Its expression in growing follicles is controlled by FSH and by estradiol (E2). In infantile females, there is a transient increase in the activity of the gonadotrope axis, as reflected by elevated levels of both gonadotropins and E2. We previously demonstrated in mice that elevated FSH concentrations are necessary to induce E2 production by preantral/early antral follicles through the stimulation of aromatase expression without supporting their growth. However, whether this action of FSH could involve AMH is unknown. Here, we show that Amh mRNA and protein abundance and serum AMH levels are elevated in infantile mouse females, compared with those in adults. By experimentally manipulating FSH and E2 levels in infantile mice, we demonstrate that high FSH concentrations lower Amh expression specifically in preantral/early antral follicles, whereas E2 has no effect. Importantly, treatment of infantile ovaries in organotypic cultures with AMH decreases FSH-mediated expression of Cyp19a1 aromatase, but it does not alter the expression of cyclin D2-mediating granulosa cell proliferation. Overall, our data indicate that the infantile elevation in FSH levels suppresses Amh expression in preantral/early antral follicles, thereby favoring Cyp19a1 aromatase expression and E2 production. Together with recent discoveries that AMH can act on both the hypothalamus and the pituitary to increase gonadotropin levels, this work suggests that AMH is a critical regulator of the gonadotrope axis during the infantile period, thereby contributing to adult reproductive function programming.

Presence of anti-Müllerian hormone (AMH) during follicular development in the porcine ovary

BACKGROUND

Anti-Müllerian hormone (AMH) is expressed by granulosa cells of developing follicles and plays an inhibiting role in the cyclic process of follicular recruitment by determining follicle-stimulating hormone threshold levels. Knowledge of AMH expression in the porcine ovary is important to understand the reproductive efficiency in female pigs.

RESEARCH AIM

In the present study we investigated the expression of AMH during follicular development in prepubertal and adult female pigs by immunohistochemistry, laser capture micro-dissection and RT-qPCR.

RESULTS AND CONCLUSION

Although in many aspects the immunohistochemical localization of AMH in the porcine ovary does not differ from other species, there are also some striking differences. As in most species, AMH appears for the first time during porcine follicular development in the fusiform granulosa cells of recruited primordial follicles and continues to be present in granulosa cells up to the antral stage. By the time follicles reach the pre-ovulatory stage, AMH staining intensity increases significantly, and both protein and gene expression is not restricted to granulosa cells; theca cells now also express AMH. AMH continues to be expressed after ovulation in the luteal cells of the corpus luteum, a phenomenon unique to the porcine ovary. The physiological function of AMH in the corpus luteum is at present not clear. One can speculate that it may contribute to the regulation of the cyclic recruitment of small antral follicles. By avoiding premature exhaustion of the ovarian follicular reserve, AMH may contribute to optimization of reproductive performance in female pigs.

BMP15 in catfish testis: Cellular distribution, seasonal variation, and its role in steroidogenesis

Considering the absence of information on testicular growth factors in fishes, present study was aimed to elucidate the existence of BMP15, an important member of TGF-β superfamily, in the testis of a seasonally breeding freshwater catfish, Clarias batrachus and its role in regulation of testicular activities. The study demonstrated the expression of BMP15 in the somatic cells (Sertoli and interstitial cells) in fish testis. The expression varied with changing testicular activity; the expression was very high in the quiescent and early recrudescing testis coinciding with the renewal of spermatogonial cells. Expression then declined gradually with progression of spermatogenesis and steroidogenesis. Expression of BMP15 showed positive correlation with seasonally changing testicular 17β-estradiol but negatively with testicular testosterone and 11-ketotestosterone. In vitro treatment of testis with recombinant human BMP15 enhanced the production of estradiol-17β but concurrently suppressed the production of testosterone and 11-ketotestosterone in testis. Though BMP15 did not alter the expression of StAR protein in the testis, it promoted the expression of 3β-hydroxysteroid dehydrogenase and aromatase in fish testis. Thus the present study for the first time demonstrates that fish testis is capable of producing BMP15 and is expressed by the somatic cells unlike mammals wherein it is produced exclusively by germ cells. Study also suggests that BMP15 may modulate the testicular steroidogenesis by altering the expression of steroidogenic enzymes. BMP15 also appears to play crucial role in renewal of spermatogial cells by augmenting the testicular production of 17β-estradiol.

The anti-Müllerian hormone (AMH) induces forkhead box L2 (FOXL2) expression in primary culture of human granulosa cells in vitro

PURPOSE

Anti-Müllerian hormone (AMH) and forkhead box L2 (FOXL2) are two pivotal genes expressed in human granulosa cells (hGCs) where both genes share similar inhibitory functions on activation and follicular growth in order to preserve the ovarian follicle reserve. Furthermore, AMH and FOXL2 contribute to inhibit steroidogenesis, decreasing or preventing the activation of gonadotrophin-dependent aromatase CYP19A1 cytochrome P450 family 19 subfamily A member 1 (CYP19A1). The purpose of this study is to evaluate the role of AMH in regulating the expression of FOXL2.

METHODS

Primary cultures of hGCs were treated with increasing concentrations of recombinant human AMH (rhAMH; range 10-100 ng/ml) for 3 h. Negative controls were performed using corresponding amounts of AMH vehicle. Total RNA or proteins were purified and quantified by spectrophotometry. FOXL2 and CYP19A1 gene expression, normalized by reference gene ribosomal protein S7 (RpS7), was evaluated by RT-qPCR. Each reaction was repeated in triplicate. Statistical analysis was performed. Extracted proteins were analyzed by immunoblot using anti-FOXL2 and anti-β-actin as primary antibodies.

RESULTS

rhAMH treatments tested did not modulate the basal expression of aromatase CYP19A1 gene. rhAMH (50 ng/ml) was able to increase FOXL2 gene expression and its intracellular content.

CONCLUSIONS

This study demonstrated the existence of an AMH-FOXL2 relationship in hGCs. AMH is capable of increasing both gene and protein expression of FOXL2. Because FOXL2 induces AMH transcription, these ovarian factors could be finely regulated by a positive feedback loop mechanism to preserve the ovarian follicle reserve.

Intra-cellular mechanism of Anti-Müllerian hormone (AMH) in regulation of follicular development

Anti-Müllerian hormone (AMH) is a member of the transforming growth factor-β superfamily and plays a crucial role in testicular and ovarian functions. In clinical practice, AMH is used as a diagnostic and/or prognostic marker in women in association with ovulation induction and in various pathophysiological conditions. Despite widespread clinical use of AMH, our mechanistic understanding of AMH actions in regulating follicular development is limited. Using a mouse model, we in this study report that in vivo AMH treatment while stalls follicular development and inhibits ovulation, also prevents follicular atresia. We further show that these AMH actions are mediated through induction of two miRNAs, miR-181a and miR-181b, which regulate various aspects of FSH signaling and follicular growth, ultimately affecting downstream gene expression and folliculogenesis. We also report that in this mouse model AMH pre-treatment prior to superovulation improves oocyte yield. These studies, therefore, offer new mechanistic insight into AMH actions in folliculogenesis and point toward potential utilization of AMH as a therapeutic agent.

Interactions between androgens, FSH, anti-Müllerian hormone and estradiol during folliculogenesis in the human normal and polycystic ovary

BACKGROUND

Androgens, FSH, anti-Müllerian hormone (AMH) and estradiol (E2) are essential in human ovarian folliculogenesis. However, the interactions between these four players is not fully understood.

OBJECTIVES AND RATIONALE

The purpose of this review is to highlight the chronological sequence of the appearance and function of androgens, FSH, AMH and E2 and to discuss controversies in the relationship between FSH and AMH. A better understanding of this interaction could supplement our current knowledge about the pathophysiology of the polycystic ovary syndrome (PCOS).

SEARCH METHODS

A literature review was performed using the following search terms: androgens, FSH, FSH receptor, anti-Mullerian hormone, AMHRII, estradiol, follicle, ovary, PCOS, aromatase, granulosa cell, oocyte. The time period searched was 1980-2015 and the databases interrogated were PubMed and Web of Science.

OUTCOMES

During the pre-antral ('gonadotropin-independent') follicle growth, FSH is already active and promotes follicle growth in synergy with theca cell-derived androgens. Conversely, AMH is inhibitory by counteracting FSH. We challenge the hypothesis that AMH is regulated by androgens and propose rather an indirect effect through an androgen-dependent amplification of FSH action on granulosa cells (GCs) from small growing follicles. This hypothesis implies that FSH stimulates AMH expression. During the antral ('gonadotropin-dependent') follicle growth, E2 production results from FSH-dependent activation of aromatase. Conversely, AMH is inhibitory but the decline of its expression, amplified by E2, allows full expression of aromatase, characteristic of the large antral follicles. We propose a theoretical scheme made up of two triangles that follow each other chronologically. In PCOS, pre-antral follicle growth is excessive (triangle 1) because of intrinsic androgen excess that renders GCs hypersensitive to FSH, with consequently excessive AMH expression. Antral follicle growth and differentiation are disturbed (triangle 2) because of the abnormally persisting inhibition of FSH effects by AMH that blocks aromatase. Beside anovulation, this scenario may also serve to explain the higher receptiveness to gonadotropin therapy and the increased risk of ovarian hyperstimulation syndrome (OHSS) in patients with PCOS.

WIDER IMPLICATIONS

Within GCs, the balance between FSH and AMH effects is pivotal in the shift from androgen- to oestrogen-driven follicles. Our two triangles hypothesis, based on updated data from the literature, offers a pedagogic template for the understanding of folliculogenesis in the normal and polycystic ovary. It opens new avenues for the treatment of anovulation due to PCOS.