Integral role of GDF-9 and BMP-15 in ovarian function

Anti-Mullerian hormone (AMH) protects ovarian follicle loss by downregulating granulosa cell function in in vitro and in vivo models

PURPOSE

AMH inhibits hormone production in luteinized granulosa cells (GCs) and stalls ovarian follicle development in vitro and in vivo. We sought to confirm AMH's mechanism of action through SMAD activation and investigate AMH inhibition of follicle development and function, in vitro and in vivo.

METHODS

A primary culture of GCs isolated from follicular fluid was used, and cells were treated with recombinant AMH (rAMH) or placebo for 24 h. For the mouse model, 18-weeks old C57BL female mice were either euthanized at the beginning or treated with rAMH or normal saline for 3 weeks. Primordial (PDF), primary follicle (PRF), secondary (SEF), and tertiary follicles (TEF) were calculated. Real-time RT-PCR and ELISA were performed to quantify GC gene expression and protein translation of human SMAD 1, 5, and 8, FSH-R and mouse FSH-R, inhibin B, caspase 3, Ki67, BMP15, GDF9, and the epigenetic regulators miRNAa and b.

RESULTS

In vitro, rAMH-treated GC showed activation of the SMAD 1, 5 and downregulation of SMAD 8, with greater magnitude at increasing rAMH doses (p < 0.04) and consequential control of downstream regulators. In vivo, the rAMH-treated mice showed increased SEFs and decreased PRFs while PDFs, TEFs, were unchanged compared with baseline. Compared with Placebo, the rAMH group showed increased PDFs, while PRFs, and TEFs were significantly decreased, and SEFs were unchanged.

CONCLUSIONS

AMH caused SMAD activation in a dose-dependent manner, with downstream downregulation of cell function and replication, also through activation of miRNAs. These mechanisms were confirmed by the in vivo findings with ultimate downregulation of follicular development and preservation of the ovarian follicle number. Counteracting follicular depletion, AMH could be used to protect the ovarian follicle reservoir.

Pluripotent stem cell-derived gametes: A gap for infertility treatment and reproductive medicine in the future

Infertility affects 10-15 % of reproductive-age couples worldwide, with male infertility linked to sperm dysfunction and female infertility caused by ovulation disorders and reproductive abnormalities. Stem cell research presents a promising avenue for infertility treatment through germ cell differentiation. However, standardizing differentiation protocols and ensuring the functionality of in vitro-derived gametes remain significant challenges before clinical application becomes feasible.

Exposure to 6PPD-Q induces dysfunctions of ovarian granulosa cells: Its potential role in PCOS

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q), an environmental pollutant derived from the ozonolysis of the widely used tire rubber antioxidant 6PPD, has been found to accumulate in air, dust, and water, posing significant health risks. While its reproductive toxicity in male organisms has been established, its effects on female reproductive health remain unclear. Polycystic ovary syndrome (PCOS), a common endocrine disorder in premenopausal women, is known to be influenced by environmental pollutants. In this study, we exposed BALB/c mice intraperitoneally to 6PPD-Q, and they exhibited PCOS-like changes after 40 days, including alterations in hormone levels, estrous cycle arrest, and polycystic ovarian morphology. Then we identified significantly elevated levels of 6PPD-Q in the follicular fluid of PCOS patients compared to those with tubal infertility, and these levels were associated with clinical parameters. In the human ovarian granulosa cell line (KGN) studies, we demonstrated that 6PPD-Q induced granulosa cell apoptosis by inhibiting the PI3K/AKT/FOXO1 pathway, leading to ovarian damage and fertility decline. To our knowledge, this is the first study to report 6PPD-Q levels in human follicular fluid and its detrimental effects on female reproductive health, underscoring the need for further research on environmental impacts on PCOS.

Evolutionary insights and expression patterns of sex-related gene families in the zig-zag eel Mastacembelus armatus

The zig-zag eel exhibits both sexual dimorphism and sex reversal, making it crucial to understand the mechanisms of sex determination and differentiation. Additionally, the wild populations of the zig-zag eel are significantly declining, emphasizing the need for urgent conservation efforts. In this study, we identified 7 Dmrt, 62 HMG-box, and 73 TGF-β family members in the zig-zag eel genome. Evolutionary analysis revealed that the HMG-box and TGF-β families in the zig-zag eel are primarily characterized by purifying selection. Furthermore, we identified 52 differentially expressed genes between males and females, with more male-biased genes than female-biased genes within these three gene families. ZzDmrt2a was highly expressed in the ovary, while ZzDmrt2b was highly expressed in the testis. Interestingly, Zzgdf9, located on the Y chromosome, was significantly expressed in the ovary. Our results highlight the complexity of sex differentiation mechanisms and underscores the importance of further research to elucidate the specific functions and regulatory networks of these sex-biased genes. Such insights could inform breeding strategies in aquaculture, contributing to the conservation and management of the zig-zag eel.

Combination of FSH and testosterone could enhance activation of primordial follicles and growth of activated follicles in 1-day-old mice ovaries in vitro cultured for 12 days

Treatment with follicle-stimulating hormone (FSH) and testosterone (T2) and their combination have been observed to be influential on ovarian follicles of 1-day-old mice ovaries cultured for 8 days. Given that extension of the culture period could positively impact the development of follicles in cultured ovaries, the present study was conducted to evaluate the main and interaction effects of FSH by T2 on the development of ovarian follicles in 1-day-old mice ovaries cultured for 12 days. One-day-old mice ovaries were initially cultured with base medium for 4 days; thereafter, different hormonal treatments were added to the culture media, and the culture was continued for 8 additional days until day 12. Ovaries were collected for histological and molecular assessments on day 12. The greatest activation of primordial follicles and progression of activated follicles to the preantral stage was detected in ovaries treated with the combination of FSH and T2 (P < 0.05). This positive effect on the morphology of ovarian follicles was accompanied by upregulation of Pi3k, Gdf9, Bmp15, Cx37 and Fshr in the ovaries cultured with the combination of FSH and T2 (P < 0.05). Nonetheless, treatment with FSH and T2 led to a diminished proportion of intact follicles (P < 0.05), even though Bax/Bcl2 gene expression ratio, as an apoptotic index, was less in hormone-treated ovaries (P < 0.05). In conclusion, the combination of FSH and T2 could improve the activation of primordial follicles and the growth of activated follicles towards the preantral stage. This positive effect of FSH plus T2 appeared to be at least partly mediated through the upregulation of Pi3k and oocyte-derived growth factors including Gdf9 and Bmp15.

Exocyst complex component 1 (Exoc1) loss in dormant oocyte disrupts c-KIT and growth differentiation factor (GDF9) subcellular localization and causes female infertility in mice

A limited number of female germ cells support reproduction in many mammals. The follicle, composed of oocytes and supporting granulosa cells, forms the basis of oogenesis. Crosstalk between oocytes and granulosa cells is essential for the formation, dormancy, re-awakening, and maturation of oocytes. The oocyte expresses c-KIT and growth differentiation factor-9 (GDF-9), which are major factors in this crosstalk. The downstream signalling pathways of c-KIT and GDF-9 have been well-documented; however, their intra-oocyte trafficking pathway remains unclear. Our study reveals that the exocyst complex, a heterotetrameric protein complex important for tethering in vesicular transport, is important for proper intra-oocyte trafficking of c-KIT and GDF9 in mice. We found that depletion of oocyte-specific EXOC1, a component of the exocyst complex, impaired oocyte re-awakening and cyst breakdown, and inhibited granulosa cell proliferation during follicle growth. The c-KIT receptor is localised on the oocyte plasma membrane. The oocyte-specific Kit conditional knockout mice were reported to exhibit impaired oocyte re-awakening and reduced oocyte cyst breakdown. GDF9 is a protein secreted extracellularly in the oocyte. Previous studies have shown that Gdf9 knockout mice impaired proliferation and granulosa cell multilayering in growing follicles. We found that both c-KIT and GDF9 abnormally stuck in the EXOC1-depleted oocyte cytoplasm. These abnormal phenotypes were also observed in oocytes depleted of exocyst complex members EXOC3 and EXOC7. These results clearly show that the exocyst complex is essential for proper intra-oocyte trafficking of c-KIT and GDF9. Inhibition of this complex causes complete loss of female fertility in mice. Our findings build a platform for research related to trafficking mechanisms of vital crosstalk factors for oogenesis.

High Carbohydrate, Fat, and Protein Diets Have a Critical Role in Folliculogenesis and Oocyte Development in Rats

To date, there is no comparative data on the effects of carbohydrates, fat, and proteins, which are macronutrients, on female reproductive functions. Therefore, in this study, we investigated the effects of diets enriched with carbohydrates, fats, and proteins on folliculogenesis and oocyte development in female rats. 21-day-old rats that were just weaned were divided into 4 groups: control, carbohydrate, fat, and protein. The control group was fed with standard chow and the carbohydrate, fat, and protein groups were fed diets enriched with 75% carbohydrate, 60% fat, and 50% protein for 11 weeks, respectively. It was found that high-fat and high-protein diets caused an increase in the estrous cycle length compared to carbohydrate group (p < 0.05). Graafian follicle number decreased in the protein group compared to the control (p < 0.05). However, the atretic follicle number was higher in the fat group compared to the control group (p < 0.05). In the carbohydrate group, Zp1 was found to be lower than the control and protein groups, Zp2 was found to be lower than the control, and Zp3 was found to be lower than the fat group (p < 0.05). While BMP15 was similar between groups (p > 0.05), GDF9 was lower in all diet groups compared to the control (p < 0.05). Foxo3a was lower in the protein group compared to carbohydrate and control (p < 0.05). GAS2 was found to be higher in the control group than the fat group, and higher in the carbohydrate group than the fat and protein groups (p < 0.05). FSH, LH, Progesterone, and E2 levels were higher in all three diet groups than in the control (p < 0.05). Also, significant differences were observed between the groups regarding adiponectin, resistin, and leptin levels. Taken together, high carbohydrate, fat, and protein intake are associated with impairment of the menstrual cycle, depletion of the developing follicle types, and altered expression of folliculogenesis-specific genes and hormones. Therefore, long-term macronutrient diets may result in shortened reproductive periods and reduced fertilization potential in females in the long run.

Association between TGF-β/BMP signaling pathway polymorphisms and the risk of primary ovarian insufficiency in Korean women

BACKGROUND

Primary ovarian insufficiency (POI) is one of the leading female infertility diseases in which ovarian function stops before the age of 40. Reports that POI is associated with transforming growth factor (TGF)-β/bone morphogenetic protein (BMP) signaling pathway-associated genes (e.g., TGF-β, and BMP15) have been continuous since publication that the TGF-β superfamily acts as important regulators for ovary and placenta function in humans. Mechanistically, the secretion of follicle-stimulating hormone, progesterone, and estrogen is affected by the TGF-β superfamily in granulosa cells, which are involved in the development of theca cells, oocytes, and granulosa cells.

OBJECTIVE

This study aimed to identify the association between genes related to the TGF-β/BMP signaling pathway and the risk of POI pathogenesis.

METHODS

Possible associations between six gene polymorphisms and POI susceptibility were examined in 139 patients with POI and 345 control subjects.

RESULTS

Allele combination of TGFBR1 rs334348 G > A and TGFBR3 rs1805110G > A exhibited association with decreased POI risk (adjusted odds ratio [AOR] = 0.165; 95% confidence interval [CI] 0.032-0.847; P = 0.031). Also, TGFBR1 rs1590 G > T and rs334348 G > A and TGFBR3 rs1805110 G > A allele combination exhibited association with decreased POI risk (OR = 0.553; 95% CI 0.374-0.816; P = 0.003).

CONCLUSION

This study suggests that polymorphisms in the TGF-β signaling pathway genes can be useful biomarkers for POI diagnosis and treatment.

Altered ovarian reserve in Ewe lambs exposed to a glyphosate-based herbicide

Glyphosate-based herbicides (GBHs) are considered endocrine disruptors that affect the female reproductive tract of rats and ewe lambs. The present study aimed to investigate the impact of neonatal exposure to a low dose of a GBH on the ovarian follicular reserve of ewe lambs and the response to a gonadotropic stimulus with porcine FSH (pFSH). To this end, ewe lambs were orally exposed to an environmentally relevant GBH dose (1 mg/kg/day) or vehicle (Control) from postnatal day (PND) 1 to PND14, and then some received pFSH (50 mg/day) between PND41 and 43. The ovaries were dissected, and follicular types and gene expression were assessed via RT-PCR. The treatments did not affect the body weight of animals, but pFSH increased ovarian weight, not observed in GBH-exposed lambs. GBH-exposed lambs showed decreased Estrogen receptor-alpha (56%), Progesterone receptor (75%), Activin receptor II (ACVRII) (85%), and Bone morphogenetic protein 15 (BMP15) (88%) mRNA levels. Control lambs treated with pFSH exhibited downregulation of Follistatin (81%), ACVRII (77%), BMP15 (93%), and FSH receptor (FSHr) (72%). GBH-exposed lambs treated with pFSH displayed reduced ACVRII (68%), BMP15 (81%), and FSHr (50%). GBH-exposed lambs also exhibited decreased Anti-Müllerian hormone expression in primordial and antral follicles (27%) and (54%) respectively) and reduced Bone morphogenetic protein 4 (31%) expression in primordial follicles. Results suggest that GBH disrupts key follicular development molecules and interferes with pFSH action in ovarian receptors, decreasing the ovarian reserve. Future studies should explore whether this decreased ovarian reserve impairs adult ovarian function and its response to superovulation stimuli.

Rescue in vitro maturation using ovarian support cells of human oocytes from conventional stimulation cycles yields oocytes with improved nuclear maturation and transcriptomic resemblance to in vivo matured oocytes

PURPOSE

Determine if the gene expression profiles of ovarian support cells (OSCs) and cumulus-free oocytes are bidirectionally influenced by co-culture during in vitro maturation (IVM).

METHODS

Fertility patients aged 25 to 45 years old undergoing conventional ovarian stimulation donated denuded immature oocytes for research. Oocytes were randomly allocated to either OSC-IVM culture (intervention) or Media-IVM culture (control) for 24-28 h. The OSC-IVM culture condition was composed of 100,000 OSCs in suspension culture with human chorionic gonadotropin (hCG), recombinant follicle stimulating hormone (rFSH), androstenedione, and doxycycline supplementation. The Media-IVM control lacked OSCs and contained the same supplementation. A limited set of in vivo matured MII oocytes were donated for comparative evaluation. Endpoints consisted of MII formation rate, morphological and spindle quality assessment, and gene expression analysis compared to in vitro and in vivo controls.

RESULTS

OSC-IVM resulted in a statistically significant improvement in MII formation rate compared to the Media-IVM control, with no apparent effect on morphology or spindle assembly. OSC-IVM MII oocytes displayed a closer transcriptomic maturity signature to IVF-MII controls than Media-IVM control MII oocytes. The gene expression profile of OSCs was modulated in the presence of oocytes, displaying culture- and time-dependent differential gene expression during IVM.

CONCLUSION

The OSC-IVM platform is a novel tool for rescue maturation of human oocytes, yielding oocytes with improved nuclear maturation and a closer transcriptomic resemblance to in vivo matured oocytes, indicating a potential enhancement in oocyte cytoplasmic maturation. These improvements on oocyte quality after OSC-IVM are possibly occurring through bidirectional crosstalk of cumulus-free oocytes and ovarian support cells.

Loss of bmp15 function in the seasonal spawner Atlantic salmon results in ovulatory failure

Bone morphogenetic protein 15 (BMP15) is an oocyte-specific growth factor important for successful female reproduction in mammals. While mutations in BMP15/Bmp15 cause ovulatory deficiency and/or infertility in certain mammalian species, loss of bmp15 in zebrafish, a continuous spawner and the only bmp15 knockout model in fish to date, results in complete arrest of follicle development and later female-to-male sex reversal, preventing to examine effects on ovulation/fertilization. Here, we used Atlantic salmon, a seasonal spawner, and generated bmp15 mutants to investigate ovarian development and fertility. Histological and morphometric analyses revealed that in biallelic frameshift (bmp15 fs/fs) mutant ovaries, folliculogenesis started earlier, resulting in an advanced development compared to wild-type (WT) controls, accompanied by a weaker expression of the (early) oocyte-specific factor figla. This precocious ovarian development was followed in bmp15 fs/fs females by enhanced follicle atresia during vitellogenic stages. Although genes involved in steroid synthesis and signaling (star, cyp11b, cyp17a1 and esr1) were dramatically higher in late vitellogenic bmp15 fs/fs mutant ovaries, estradiol-17β plasma levels were lower than in WT counterparts, potentially reflecting compensatory changes at the level of ovarian gene expression. At spawning, bmp15 fs/fs females displayed lower gonado-somatic index values and reduced oocyte diameter, and the majority (71.4%), showed mature non-ovulating ovaries with a high degree of atresia. The remaining (28.6%) females spawned eggs but they either could not be fertilized or, upon fertilization, showed severe malformations and embryonic mortality. Our results show that Bmp15 is required for proper follicle recruitment and growth and later ovulatory success in Atlantic salmon, providing an alternative candidate target to induce sterility in farmed salmon. Moreover, since loss of bmp15 in salmon, in contrast to zebrafish, does not result in female-to-male sex change, this is the first mutant model in fish allowing further investigations on Bmp15-mediated functions in the ovulatory period.

Factors defining developmental competence of bovine oocytes collected for in vitro embryo production†

Despite the currently relatively low effectiveness of producing bovine embryos in vitro, there is a growing interest in applying this laboratory method in the field of reproduction. Many aspects of the procedure need to be improved. One of the main problems is the inferior developmental competence of in vitro matured oocytes that are collected using the ovum pick-up method. The mechanisms of oocyte capacitation and maturation, as well as the in vivo conditions in which they grow and mature, should be carefully analyzed. A deliberate application of the identified mechanisms and beneficial factors affecting the in vitro procedures seems to be essential for achieving higher developmental competence of the oocytes that are subjected to fertilization. The results may be improved by developing and employing a laboratory maturation protocol that corresponds with appropriate preparation of donors before the ovum pick-up, an optimized hormonal treatment program, the appropriate size of ovarian follicles at the time of aspiration, and a fine-tuned coasting period.

Chronic Fluoride Exposure Induces Ovarian Dysfunction and Potential Association with Premature Ovarian Failure in Female Rats

Chronic fluorosis has been widely investigated for its adverse effects on skeletal and neurological health; however, its impact on reproductive health, especially in females, remains underexplored. In this study, female Sprague-Dawley rats were exposed to different fluoride concentrations (0.75, 50, and 100 mg/L) in their drinking water for six months. Dental fluorosis and increased urinary fluoride content were observed in fluoride-exposed rats, reflecting fluoride accumulation and exposure levels. Chronic fluorosis resulted in reduced ovary organ coefficient, indicating harmful effects on ovarian tissue. Additionally, the number of ovarian primordial and primary/secondary follicles decreased, while the number of atresia follicles increased. Furthermore, chronic fluorosis led to disrupted estrous cycles. Hormonal analysis revealed altered secretion of estrogen, progesterone, anti-Müllerian hormone, luteinizing hormone, follicular stimulating hormone, and inhibin B in response to fluoride exposure. Ultrastructural observation of ovarian granulosa cells showed evidence of apoptosis, which was further confirmed by flow cytometry. Caspase-3 activity was increased, and ATP levels were decreased, suggesting mitochondrial impairment and apoptosis induction. The mRNA and protein expression of BMP15 and GDF9, essential regulators of ovarian function, significantly decreased with increasing fluoride concentration. Furthermore, gene expression analysis identified a panel of premature ovarian failure-related genes that were downregulated in fluoride-exposed rat ovaries. These findings suggest that chronic fluoride exposure may contribute to ovarian dysfunction and possibly the pathogenesis of premature ovarian failure. Understanding the toxicological effects of chronic fluoride exposure on ovarian function is essential for identifying potential environmental risk factors affecting female reproductive health.

The Roles of GDF-9, BMP-15, BMP-4 and EMMPRIN in Folliculogenesis and In Vitro Fertilization

Growth differentiation factor 9 (GDF-9) contributes to early ovarian development and oocyte survival. Higher concentrations of GDF-9 in follicular fluid (FF) are associated with oocyte nuclear maturation and optimal embryo development. In in vitro fertilization (IVF), GDF-9 affects the ability of the oocyte to fertilize and subsequent embryonic development. Bone morphogenetic protein 15 (BMP-15) is involved in the regulation of ovarian function and affects oocyte development. During IVF, BMP-15 contributes to the formation of competent blastocysts. BMP-15 may play a role in embryo implantation by affecting endometrial receptivity. Bone morphogenetic protein 4 (BMP-4) is involved in the regulation of follicle growth and development and affects granulosa cell (GC) differentiation. In relation to IVF, BMP-4 is important for embryonic development, influences cell fate and differentiation, and plays a role in facilitating embryo-endometrial interactions during the implantation process. Extracellular matrix metalloproteinase inducer (EMMPRIN) is associated with ovulation and follicle rupture, promotes the release of mature eggs, and affects the modification of the extracellular matrix of the follicular environment. In IVF, EMMPRIN is involved in embryo implantation by modulating the adhesive properties of endometrial cells and promotes trophoblastic invasion, which is essential for pregnancy to occur. The purpose of the current article is to review the studies and recent findings of GDF-9, BMP-15, BMP-4 and EMMPRIN as fundamental factors in normal follicular development and in vitro fertilization.

FOXL2 and NR5A1 induce human fibroblasts into steroidogenic ovarian granulosa-like cells

Human granulosa cells in different stages are essential for maintaining normal ovarian function, and granulosa cell defect is the main cause of ovarian dysfunction. To address this problem, it is necessary to induce functional granulosa cells at different stages in vitro. In this study, we established a reprogramming method to induce early- and late-stage granulosa cells with different steroidogenic abilities. We used an AMH-fluorescence-reporter system to screen candidate factors for cellular reprogramming and generated human induced granulosa-like cells (hiGC) by overexpressing FOXL2 and NR5A1. AMH-EGFP+ hiGC resembled human cumulus cells in transcriptome profiling and secreted high levels of oestrogen and progesterone, similar to late-stage granulosa cells at antral or preovulatory stage. Moreover, we identified CD55 as a cell surface marker that can be used to isolate early-stage granulosa cells. CD55+ AMH-EGFP- hiGC secreted high levels of oestrogen but low levels of progesterone, and their transcriptome profiles were more similar to early-stage granulosa cells. More importantly, CD55+ hiGC transplantation alleviated polycystic ovary syndrome (PCOS) in a mouse model. Therefore, hiGC provides a cellular model to study the developmental program of human granulosa cells and has potential to treat PCOS.

Growth differentiation factor 9 regulates the expression of estrogen receptors via Smad2/3 signaling in goat cumulus cells

Both oocyte secretory factors (OSFs) and estrogen are essential for the development and function of mammalian ovarian follicles, playing synergistic role in regulating oocyte growth. OSFs can significantly affect the biological processes regulated by estrogen in cumulus cells (CCs). It is a scientific question worth investigating whether oocyte secretory factors can influence the expression of estrogen receptors in CCs. In our study, we observed a significant increase in the mRNA and protein expressions of estrogen receptor β (Esr2/ERβ) and G-protein-coupled estrogen receptor (GPER) in cumulus cells of goat cumulus-oocyte complexes (COCs) cultured in vitro for 6 h. Furthermore, the addition of 10 ng/mL growth-differentiation factor 9 (GDF9) and 5 ng/mL bone morphogenetic protein 15 (BMP15) to the culture medium of goat COCs resulted in a significant increase in the expressions of ERβ and GPER in cumulus cells. To explore the mechanism further, we performed micromanipulation to remove oocyte contents and co-cultured the oocytectomized complexes (OOXs) with denuded oocytes (DOs) or GDF9/BMP15. The expressions of ERβ and GPER in the co-culture groups were significantly higher than those in the OOXs group, but there was no difference compared to the COCs group. Mechanistically, we found that SB431542 (inhibitor of GDF9 bioactivity), but not LDN193189 (inhibitor of BMP15 bioactivity), abolished the upregulation of ERβ and GPER in cumulus cells and the activation of Smad2/3 signaling. In conclusion, our results demonstrate that the oocyte secretory factor GDF9 promotes the activation of Smad2/3 signaling in cumulus cells during goat COCs culture in vitro, and the phosphorylation of Smad2/3 induces the expression of estrogen receptors ERβ and GPER in cumulus cells.

Implication of Novel BMP15 and GDF9 Variants in Unexpected Poor Ovarian Response

Unexpected poor ovarian response (UPOR) occurs when nine or fewer oocytes are retrieved from a young patient with normal ovarian reserve. Bone morphogenetic protein15 (BMP15) and growth differentiation factor 9 (GDF9) are two oocyte-specific factors with pivotal role in folliculogenesis. The aim of this study was to assess the relation between BMP15 and GDF9 variants with UPOR. Hundred women aged ≤ 39 with AMH ≥ 1.27 IU/ml participated as UPOR and normal ovarian responders (NOR) based on their oocyte number. Each group consisted of 50 patients. After genomic DNA extraction, the entire exonic regions of BMP15 and GDF9 were amplified and examined by direct sequencing. Western blotting was performed to determine the expression levels of BMP15 and GDF9 in follicular fluid. Additionally, in silico analysis was applied to predict the effect of discovered mutations. From four novel variants of BMP15 and GDF9 genes, silent mutations (c.744 T > C) and (c.99G > A) occurred in both groups, whereas missense variants: c.967-968insA and c.296A > G were found exclusively in UPORs. The latter variants caused reduction in protein expression. Moreover, the mutant allele (T) in a GDF9 polymorphism (C447T) found to be more in NOR individuals (58% NOR vs. 37% UPOR (OR = 2.3, CI 1.32-4.11, p = 0.004).The novel missense mutations which were predicted as damaging, along with other mutations that happened in UPORs might result in ovarian resistance to stimulation. The mutant allele (T) in C447T polymorphism has a protective effect. It can be concluded that there is an association between BMP15 and GDF9 variants and follicular development and ovarian response.

In-vitro generation of follicle-like structures from human germ cell-like cells derived from theca stem cell combined with ovarian somatic cells

BACKGROUND

The objective of this study was to induce the differentiation of human theca stem cells (hTSCs) into germ cell-like cells (hGCLCs) and assess their developmental progression following in vitro 3D culture with ovarian somatic cells within the follicle-like structures. To achieve this, the hTSCs were isolated from small antral follicles of three patients of varying ages and were then seeded in a differentiation medium for 40 days. The differentiated hGCLCs were subsequently aggregated with somatic ovarian cells (cumulus cells and hTSCs) in a ratio of 1:10 and cultured in a growth medium in a suspension culture dish. In addition to examining the morphologies, sizes, and viabilities of the differentiated hGCLCs, this study also analyzed the expression of DAZL and GDF9 proteins within the follicle-like structures.

RESULTS

After 12 days, the hTSCs began to differentiate into hGCLCs, with their shapes changing from spindle-shaped to spherical. The sizes of hGCLCs increased during the differentiation period (from 25 μm to 50 μm). The survival rate of the hGCLCs after differentiation and in vitro development in primordial follicle-like structures was 54%. Unlike hTSCs, which did not express the DAZL protein, the hGCLCs and follicle-like structures successfully expressed DAZL protein (P-value < 0.05). However, hGCLCs poorly expressed the GDF9 protein. Further, the culture of hGCLCs in primordial follicle-like structures significantly increased GDF9 expression (P-value < 0.05).

CONCLUSION

In conclusion, our study demonstrated that 3D cultures with ovarian somatic cells in follicle-like structures caused the successful differentiation of reproducible hGCLCs from hTSCs derived from three patients of different ages. Moreover, this method not only enhanced the in vitro development of hGCLCs but also presented a novel approach for co-culturing and developing in vitro oocyte like cells, ultimately leading to the production of artificial follicles.

Molecular Mechanisms Determining Mammalian Oocyte Quality with the Treatment of Cancer Therapy

Cancer is a global public health issue and remains one of the leading causes of death in the United States (Siegel et al. CA Cancer J Clin. 72:7-33, 2022). It is estimated in the US in 2022, about 935,000 new cases of cancer will be diagnosed in women, and the probability of developing invasive cancer is 5.8% for females younger than 50 years old (Siegel et al. CA Cancer J Clin. 72:7-33, 2022). However, advances in screening programs, diagnostic methods, and therapeutic options have greatly increased the five-year survival rate in reproductive-age women with a variety of cancers. Given the clinical consequences of gonadotoxic cancer therapies, young, female cancer survivors may face compromised fertility, premature ovarian insufficiency, early-onset menopause, and endocrine dysregulation (Bedoschi et al. Future Oncol. 12:2333-44, 2016). Gonadotoxic side effects may include decreased oocyte quality within surviving follicles, loss of ovarian follicles, and impaired ovarian function. In reproductive-age women, oocyte quality is an important element for successful clinical pregnancies and healthy offspring as poor-quality oocytes may be a cause of infertility (McClam et al. Biol Reprod. 106:328-37, 2022; Marteil et al. Reprod Biol. 9:203-24, 2009; Krisher. J Anim Sci. 82: E14-E23, 2004). Thus, it is critical to determine the quantity and quality of surviving follicles in the ovary after cancer treatment and to assess oocyte quality within those surviving follicles as these are markers for determining the capacity for ovarian function restoration and future fertility, especially for young cancer survivors (Xu et al. Nat Med. 17:1562-3, 2011). The long-term effects of cancer therapeutics on oocyte quality are influenced by factors including, but not limited to, individual patient characteristics (e.g. age, health history, comorbidities, etc.), disease type, or treatment regimen (Marci et al. Reprod Biol Endocrinol. 16:1-112, 2018). These effects may translate clinically into an impaired production of viable oocytes and compromised fertility (Garutti et al. ESMO Open. 6:100276, 2021).

Growth factors and female reproduction in vertebrates

Female reproductive efficiency is influenced by the outcomes of various processes, including folliculogenesis, apoptosis, response to gonadotropin signaling, oocyte maturation, and ovulation. The role of hormones in regulating these processes and other reproductive activities has been well established. It is becoming increasingly evident that in addition to well-characterized hormones, growth factors play vital roles in regulating some of these reproductive activities. Growth factors and their receptors are widely distributed in vertebrate ovaries at different stages of ovarian development, indicating their involvement in intraovarian reproductive functions. In the ovary, cell surface receptors allow growth factors to regulate intraovarian reproductive activities. Understanding these actions in the reproductive axis would provide a tool to target growth factors and/or their receptors to yield desirable reproductive outcomes. These include enrichment of in vitro maturation and fertilization culture media, and management of infertility. This review discusses some widely characterized growth factors belonging to the TGF, EGF, IGF, FGF, and BDNF family of peptides and their role in female reproduction in vertebrates, with a focus on mammals.

Detection of genetic variations in the GDF9 and BMP15 genes in Kazakh meat-wool sheep

Kazakh meat-wool sheep are of great interest because of the intrabreed multifetal type's high productivity of 140 %-160 %. Genes encoding growth differentiation factor-9 (GDF9) and bone morphogenetic protein 15 (BMP15) are promising candidates for studying sheep productivity, as they affect fertility in mammals, including sheep. Thus, the purpose of this study was to assess the fertility of the Kazakh meat-wool sheep breed based on GDF9 and BMP15 candidate genes of fecundity for the selection of animals with valuable genotypes. We selected 300 heads of the Kazakh meat-wool sheep breed from two populations for PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) analysis, 15 of which were subsequently used for sequencing of exon regions of the GDF9 and BMP15 genes. The sheep populations were tested for G1 and G8 mutations of the GDF9 gene and B2 and B4 mutations of the BMP15 gene. The PCR-RFLP analysis revealed that 59 (19.7 %) of the 300 Kazakh meat-wool breed sheep were heterozygous carriers of the G1 mutation (genotype AG) of the GDF9 gene, and sequencing analysis supported these results. The comparative phylogenetic analysis showed a clear separation of Kazakh meat-wool sheep wild types and carriers of the G1 mutation. This mutation was reported to have a relationship with the animals' litter size in other sheep breeds. For this reason, similar relationships should be investigated in Kazakh meat-wool sheep. However, G8, B2, and B4 mutations were not detected among the studied animal populations, showing that these mutations are not characteristic of the Kazakh meat-wool sheep breed.

A DNA Methylation Perspective on Infertility

Infertility affects a significant number of couples worldwide and its incidence is increasing. While assisted reproductive technologies (ART) have revolutionized the treatment landscape of infertility, a significant number of couples present with an idiopathic cause for their infertility, hindering effective management. Profiling the genome and transcriptome of infertile men and women has revealed abnormal gene expression. Epigenetic modifications, which comprise dynamic processes that can transduce environmental signals into gene expression changes, may explain these findings. Indeed, aberrant DNA methylation has been widely characterized as a cause of abnormal sperm and oocyte gene expression with potentially deleterious consequences on fertilization and pregnancy outcomes. This review aims to provide a concise overview of male and female infertility through the lens of DNA methylation alterations.

Genetic evidence for differential functions of figla and nobox in zebrafish ovarian differentiation and folliculogenesis

FIGLA and NOBOX are important oocyte-specific transcription factors. Both figla-/- and nobox-/- mutants showed all-male phenotype in zebrafish due to increased dominance of the male-promoting pathway. The early diversion towards males in these mutants has precluded analysis of their roles in folliculogenesis. In this study, we attenuated the male-promoting pathway by deleting dmrt1, a key male-promoting gene, in figla-/- and nobox-/- fish, which allows a sufficient display of defects in folliculogenesis. Germ cells in figla-/-;dmrt1-/- double mutant remained in cysts without forming follicles. In contrast, follicles could form well but exhibited deficient growth in nobox-/-;dmrt1-/- double mutants. Follicles in nobox-/-;dmrt1-/- ovary could progress to previtellogenic (PV) stage but failed to enter vitellogenic growth. Such arrest at PV stage suggested a possible deficiency in estrogen signaling. This was supported by lines of evidence in nobox-/-;dmrt1-/-, including reduced expression of ovarian aromatase (cyp19a1a) and level of serum estradiol (E2), regressed genital papilla (female secondary sex characteristics), and more importantly the resumption of vitellogenic growth by E2 treatment. Expression analysis suggested Nobox might regulate cyp19a1a by controlling Gdf9 and/or Bmp15. Our discoveries indicate that Figla is essential for ovarian differentiation and follicle formation whereas Nobox is important for driving subsequent follicle development.

Optimisation of hormonal treatment to improve follicular development in one-day-old mice ovaries cultured under in vitro condition

CONTEXT

Base medium containing knock-out serum replacement (KSR) has been found to support formation and maintenance of follicles in one-day-old mice ovaries, but has not been shown to properly support activation and growth of primordial follicles.

AIMS

The present study was conducted to tailor the hormonal content of base medium containing KSR to enhance development of primordial follicles in neonatal ovaries.

METHODS

One-day-old mice ovaries were initially cultured with base medium for four days, and then, different hormonal treatments were added to the culture media and the culture was proceeded for four additional days until day eight. Ovaries were collected for histological and molecular assessments on days four and eight.

KEY RESULTS

In experiment I, the main and interactive effects of FSH and testosterone were investigated and FSH promoted activation of primordial follicles and development of primary and preantral follicles, and upregulated genes of phosphoinositide 3-kinase (Pi3k ), KIT ligand (Kitl ), growth differentiation factor 9 (Gdf9 ) and follicle stimulating hormone receptor (Fshr ) (P Bmp15 ), Connexin-43 (Cx43 ) and luteinising hormone and choriogonadotropin receptor (Lhcgr ) (P P Lhcgr (P P >0.05).

CONCLUSIONS

Supplementation of culture medium containing KSR with gonadotropins, particularly hMG, could improve follicular growth and expression of factors regulating follicular development.

IMPLICATIONS

This study was a step forward in formulating an optimal medium for development of follicles in cultured one-day-old mice ovaries.

Gonacin: A germ cell-derived hormone with glucogenic, orexigenic, and gonadal activities

Fish require abundant nutrients to generate a large number of eggs for spawning. Based on the evolutionary conservation of human FBN2 and its C-terminal placensin-like sequences in fish, we identified a peptide hormone gonacin (GONAdal Cell placensIN) and found its high expression in early-stage germ cells in the ovary and testis of zebrafish. We demonstrated that gonacin is essential for food intake, glucose release, and ovarian development in zebrafish. Similar expression patterns and functions of gonacin were also demonstrated in rainbow trout. Gonacin represents the first hormone secreted by germ cells with endocrine functions in vertebrates, bridging the energy homeostasis and reproduction.

Rescue of bmp15 deficiency in zebrafish by mutation of inha reveals mechanisms of BMP15 regulation of folliculogenesis

As an oocyte-specific growth factor, bone morphogenetic protein 15 (BMP15) plays a critical role in controlling folliculogenesis. However, the mechanism of BMP15 action remains elusive. Using zebrafish as the model, we created a bmp15 mutant using CRISPR/Cas9 and demonstrated that bmp15 deficiency caused a significant delay in follicle activation and puberty onset followed by a complete arrest of follicle development at previtellogenic (PV) stage without yolk accumulation. The mutant females eventually underwent female-to-male sex reversal to become functional males, which was accompanied by a series of changes in secondary sexual characteristics. Interestingly, the blockade of folliculogenesis and sex reversal in bmp15 mutant could be partially rescued by the loss of inhibin (inha-/-). The follicles of double mutant (bmp15-/-;inha-/-) could progress to mid-vitellogenic (MV) stage with yolk accumulation and the fish maintained their femaleness without sex reversal. Transcriptome analysis revealed up-regulation of pathways related to TGF-β signaling and endocytosis in the double mutant follicles. Interestingly, the expression of inhibin/activin βAa subunit (inhbaa) increased significantly in the double mutant ovary. Further knockout of inhbaa in the triple mutant (bmp15-/-;inha-/-;inhbaa-/-) resulted in the loss of yolk granules again. The serum levels of estradiol (E2) and vitellogenin (Vtg) both decreased significantly in bmp15 single mutant females (bmp15-/-), returned to normal in the double mutant (bmp15-/-;inha-/-), but reduced again significantly in the triple mutant (bmp15-/-;inha-/-;inhbaa-/-). E2 treatment could rescue the arrested follicles in bmp15-/-, and fadrozole (a nonsteroidal aromatase inhibitor) treatment blocked yolk accumulation in bmp15-/-;inha-/- fish. The loss of inhbaa also caused a reduction of Vtg receptor-like molecules (e.g., lrp1ab and lrp2a). In summary, the present study provided comprehensive genetic evidence that Bmp15 acts together with the activin-inhibin system in the follicle to control E2 production from the follicle, Vtg biosynthesis in the liver and its uptake by the developing oocytes.

Decreased growth differentiation factor 9, bone morphogenetic protein 15, and forkhead box O3a expressions in the ovary via ulipristal acetate

OBJECTIVE

Folliculogenesis is a complex process involving various ovarian paracrine factors. During folliculogenesis, vitamin D3 and progesterone are significant for the proper development of follicles. This study aimed to investigate the effects of vitamin D3 and selective progesterone receptor modulator ulipristal acetate on ovarian paracrine factors.

METHODS

In the study, 18 female Wistar-albino rats were randomly divided into three groups: control group (saline administration, n=6), vitamin D3 group (300 ng/day vitamin D3 oral administration, n=6), and UPA group (3 mg/kg/day ulipristal acetate oral administration, n=6). Ovarian tissue was analyzed by histochemistry and immunohistochemistry. For quantification of immunohistochemistry, the mean intensities of growth differentiation factor 9, bone morphogenetic protein 15, and forkhead box O3a expressions were measured by Image J and MATLAB. Blood samples were collected for the analysis of serum anti-Müllerian hormone levels by ELISA.

RESULTS

Atretic follicles and hemorrhagic cystic structures were observed in the UPA group. After immunohistochemistry via folliculogenesis assessment markers, growth differentiation factor 9, bone morphogenetic protein 15, and cytoplasmic forkhead box O3a expressions decreased in the UPA group (p<0.05). Anti-Müllerian hormone level did not differ significantly between the experimental groups (p>0.05).

CONCLUSION

Ulipristal acetate negatively affects folliculogenesis via ovarian paracrine factors. The recommended dietary vitamin D3 supplementation in healthy cases did not cause a significant change.

Nanowarming improves survival of vitrified ovarian tissue and follicular development in a sheep model

Tissue cryopreservation has allowed long term banking of biomaterials in medicine. Ovarian tissue cryopreservation in particular helps patients by extending their fertility window. However, protection against tissue injury during the thawing process has proven to be challenging. This is mainly due to the heterogenous and slow distribution of the thermal energy across the vitrified tissue during a conventional warming process. Nanowarming is a technique that utilizes hyperthermia of magnetic nanoparticles to accelerate this process. Herein, hyperthermia of synthesized PEGylated silica-coated iron oxide nanoparticles was used to deter the injury of cryopreserved ovarian tissue in a sheep model. When compared to the conventional technique, our findings suggest that follicular development and gene expression in tissues warmed by the proposed technique have been improved. In addition, Nanowarming prevented cellular apoptosis and oxidative stress. We therefore conclude that Nanowarming is a potential complementary candidate to increase efficiency in the ovarian cryopreservation field.

The effect of maternal consumption of high-fat diet on ovarian development in offspring

The environment encountered by the fetus during its development exerts a profound influence on its physiological function and disease risk in adulthood. Women's intake of high-fat diet during pregnancy and lactation has gradually become an issue of widespread concern. Maternal high-fat diet will not only cause abnormal neurological development and metabolic syndrome symptoms in the offspring, but also affect the fertility of female offspring. Maternal high-fat diet affects the expression of genes related to follicle growth in offspring, such as AAT, AFP and GDF-9, which reduces the number of follicles and impairs follicle development. Additionally, maternal high-fat diet also affects ovarian health by inducing ovarian oxidative stress and cell apoptosis, which collectively can impair the reproductive potential of female offspring. Reproductive potential carries significant importance for both humans and animals. Therefore, this review aims to describe the effect of maternal exposure to high-fat diet on the ovarian development of offspring and to discuss possible mechanisms by which maternal diet affects the growth and metabolism of offspring.

From in vivo to in vitro: exploring the key molecular and cellular aspects of human female gametogenesis

Human oogenesis is a highly complex and not yet fully understood process due to ethical and technological barriers that limit studies in the field. In this context, replicating female gametogenesis in vitro would not only provide a solution for some infertility problems, but also be an excellent study model to better understand the biological mechanisms that determine the formation of the female germline. In this review, we explore the main cellular and molecular aspects involved in human oogenesis and folliculogenesis in vivo, from the specification of primordial germ cells (PGCs) to the formation of the mature oocyte. We also sought to describe the important bidirectional relationship between the germ cell and the follicular somatic cells. Finally, we address the main advances and different methodologies used in the search for obtaining cells of the female germline in vitro.

Biochanin-A attenuates DHEA-induced polycystic ovary syndrome via upregulation of GDF9 and BMP15 signaling in vivo

AIMS

Phytoestrogens can act as natural estrogens owing to their structural similarity to human estrogens. Biochanin-A (BCA) is a well-studied phytoestrogen with a wide variety of pharmacological activities, whereas not reported in the most frequently encountered endocrinopathy called polycystic ovary syndrome (PCOS) in women.

PURPOSE

This study aimed to investigate the therapeutic effect of BCA on dehydroepiandrosterone (DHEA) induced PCOS in mice.

MAIN METHODS

Thirty-six female C57BL6/J mice were divided into six groups: sesame oil, DHEA-induced PCOS, DHEA + BCA (10 mg/kg/day), DHEA + BCA (20 mg/kg/day), DHEA + BCA (40 mg/kg/day), and metformin (50 mg/kg/day).

KEY FINDINGS

The results showed a decrease in obesity, elevated lipid parameters, restoration of hormonal imbalances (testosterone, progesterone, estradiol, adiponectin, insulin, luteinizing hormone, and follicle-stimulating hormone), estrus irregular cyclicity, and pathological changes in the ovary, fat pad, and liver.

SIGNIFICANCE

In conclusion, BCA supplementation inhibited the over secretion of inflammatory cytokines (TNF-α, IL-6, and IL-1β) and upregulated TGFβ superfamily markers such as GDF9, BMP15, TGFβR1, and BMPR2 in the ovarian milieu of PCOS mice. Furthermore, BCA reversed insulin resistance by increasing circulating adiponectin levels through a negative correlation with insulin levels. Our results indicate that BCA attenuated DHEA-induced PCOS ovarian derangements, which could be mediated by the TGFβ superfamily signaling pathway via GDF9 and BMP15 and associated receptors as first evidenced in this study.

The emerging role of lysine succinylation in ovarian aging

BACKGROUND

Ovarian aging is a process of decline in its reserve leading to ovary dysfunction and even reduced health quality in offspring. However, aging-related molecular pathways in the ovary remain obscure. Lysine succinylation (Ksuc), a newly post-translational modification (PTM), has been found to be broadly conserved in both eukaryotic and prokaryotic cells, and associated with multiple pathophysiological processes. There are no relevant reports revealing a link between the molecular mechanisms of ovarian aging and Ksuc.

METHODS

The level of Ksuc in ovaries of aged and premature ovarian insufficiency (POI) mice were detected by immunoblotting and immunohistochemical. To further explore the role of Ksuc in ovarian aging, using in vitro mouse ovary tissue culture and an in vivo mouse model with changed Ksuc level.

RESULTS

Increased Ksuc in ovaries of aged and POI mice and distribution of Ksuc in various types of mice ovarian cells and the high level of Ksuc in granulosa cells (GCs) were revealed. Histological assessments and hormone levels analyses showed that the high Ksuc level down-regulated the ovarian index and the anti-Müllerian hormone (AMH) and estrogen levels, and increased follicular atresia. Moreover, in the high Ksuc groups, the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) intensities and the expression of Cleaved-caspase-3 increased and the expression of B-cell lymphoma-2 (Bcl-2) decreased together with positively-expressed P21, an aging-related marker. These results suggest that ovarian aging is likely associated with alteration in Ksuc.

CONCLUSION

The present study has identified Ksuc in mouse ovary and found that high Ksuc level most likely contributes to ovarian aging which is expected further investigation to provide new information for delaying physiological ovarian aging and treating pathological ovarian aging.

Melatonin effective to reduce the microscopic symptoms of polycystic ovary syndrome-related infertility: An experimental study

Polycystic ovary syndrome (PCOS) is an endocrine disorder seen in women of reproductive age and has been gradually increasing over the years. The mechanism of the syndrome has still not been clearly understood. In this study, the possible effects of exogenously administrated melatonin on melatonin (MT1) receptor, Growth Differentiation Factor-9 (GDF9), and Bone Morphogenetic Protein-15 (BMP15) in experimental PCOS were investigated. Thirty-two 6-8-week-old Sprague-Dawley rats were randomly divided into four groups (n = 8 in each) as Sham control (Group 1), Melatonin (Group 2), PCOS (Group 3), and PCOS + Melatonin (Group 4) groups. At the end of the 21st day, the experiment was terminated, the ovary tissues were taken, and Hematoxylin-Eosin staining, MT1, GDF9, BMP15 immunohistochemical labeling, western blot, and quantitative real-time polymerase chain reaction (qPCR) analyses were performed. Serum Luteinizing Hormone (LH)/Follicle Stimulating Hormone (FSH) levels and colpo-cytological examinations were also carried out. The results revealed that melatonin administration increased the expression levels of the MT1 receptor, GDF9, and BMP15 in PCOS at protein and mRNA levels. It was determined that melatonin administration reduced the microscopic symptoms of PCOS. Melatonin was found to be effective via the MT1 receptor in the pathogenesis of PCOS, and it suppressed the transport pathways of GDF9 to granulosa cells in antral follicles.

Resolving the challenge of insoluble production of mature human growth differentiation factor 9 protein (GDF9) in E. coli using bicistronic expression with thioredoxin

Growth differentiation factor 9 (GDF9) is an oocyte-derived protein with fundamental functions in folliculogenesis. While the crucial contributions of GDF9 in follicular survival have been revealed, crystallographic studies of GDF9 structure have not yet been carried out, essentially due to the insoluble expression of GDF9 in E. coli and lack of appropriate source for structural studies. Therefore, in this study, we investigated the impact of different expression rate of bacterial thioredoxin (TrxA) using bicistronic expression constructs to induce the soluble expression of mature human GDF9 (hGDF9) driven by T7 promoter in E. coli. Our findings revealed that in BL21(DE3), the high rate of TrxA co-expression at 30 °C was sufficiently potent for the soluble expression of hGDF9 and reduction of inclusion body formation by 4 fold. We also successfully confirmed the bioactivity of the purified soluble hGDF9 protein by evaluation of follicle-stimulating hormone receptor gene expression in bovine cumulus cells derived from small follicles. This study is the first to present an effective approach for expression of bioactive form of hGDF9 using TrxA co-expression in E. coli, which may unravel the current issues regarding structural analysis of hGDF9 protein and consequently provide a better insight into hGDF9 functions and interactions.

Combination treatment of recombinant growth differentiation factor-9 and Cetrorelix improves gestational origin of the polycystic ovarian syndrome in female rats

AIMS

Polycystic ovary syndrome (PCOS) is a hyper-androgenic endocrinopathy prevalent in premenopausal women with no cure available. The current study aimed to investigate the therapeutic effect of recombinant GDF-9 and Cetrorelix on the gestational origin of dehydroepiandrosterone (DHEA) induced PCOS in postnatal pups' delivered to rat dams.

MAIN METHODS

The body weight measurement, blood and serum analysis for glucose tolerance, lipid profile, liver enzymes, sex hormones (Testosterone, Estradiol, and Progesterone), estrus cyclicity assessment, histological staining of ovary and liver, molecular markers expressions of pro-inflammatory by qRT-PCR and immuno-histochemistry technique for folliculogenesis genes and histological staining studies of liver and ovary were done.

KEY FINDINGS

The combinational treatment was found to normalize the biochemical parameters and reduction in the estrus irregularity by altering the sex hormones as well as the glucose metabolism and insulin resistance via HOMA-IR value. Further, molecular markers expression confirmed the pro-inflammatory (IL-1β, TNF-α, and IL-6) and folliculogenesis (GDF-9, BMPR2, and TGF-βR1) genes associated with PCOS were improved by combinational therapy.

SIGNIFICANCE

In conclusion, rGDF-9 could be a potential therapeutic agent in combination with Cetrorelix as a better treatment regime for metabolic and reproductive phenotypes in PCOS. However, the effect of rGDF-9 on infertility-associated phenotypes in PCOS needs further evaluation.

Effects of Zishen Yutai Pills on in vitro Fertilization-Embryo Transfer Outcomes in Patients with Diminished Ovarian Reserve: A Prospective, Open-Labeled, Randomized and Controlled Study

OBJECTIVE

To explore the effects of Zishen Yutai Pills (ZYPs) on the quality of oocytes and embryos, as well as pregnancy outcomes in patients with diminished ovarian reserve (DOR) receiving in vitro fertilization-embryo transfer (IVF-ET). The possible mechanisms, involving the regulation of bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9), were also investigated.

METHODS

A total of 120 patients with DOR who underwent their IVF-ET cycle were randomly allocated to 2 groups in a 1:1 ratio. The patients in the treatment group (60 cases) received ZYPs from the mid-luteal phase of the former menstrual cycle by using gonadotropin-releasing hormone (GnRH) antagonist protocol. The patients in the control group (60 cases) received the same protocol but without ZYPs. The primary outcomes were the number of oocytes retrieved and high-quality embryos. Secondary outcomes included other oocyte or embryo indices as well as pregnancy outcomes. Adverse events were assessed by comparison of the incidence of ectopic pregnancy, pregnancy complications, pregnancy loss, and preterm birth. Contents of BMP15 and GDF9 in the follicle fluids (FF) were also quantified with enzyme-linked immunosorbent assay.

RESULTS

Compared with the control group, the numbers of oocytes retrieved and high-quality embryos were significantly increased in the ZYPs group (both P<0.05). After treatment with ZYPs, a significant regulation of serum sex hormones was observed, including progesterone and estradiol. Both hormones were up-regulated compared with the control group (P=0.014 and 0.008), respectively. No significant differences were observed with regard to pregnancy outcomes including implantation rates, biochemical pregnancy rates, clinical pregnancy rates, live birth rates, and pregnancy loss rates (all P>0.05). The administration of ZYPs did not increase the incidence of adverse events. The expressions of BMP15 and GDF9 in the ZYPs group were significantly up-regulated compared with the control group (both P<0.05).

CONCLUSIONS

ZYPs exhibited beneficial effects in DOR patients undergoing IVF-ET, resulting in increments of oocytes and embryos, and up-regulation of BMP15 and GDF9 expressions in the FF. However, the effects of ZYPs on pregnancy outcomes should be assessed in clinical trials with larger sample sizes (Trial reqistration No. ChiCTR2100048441).

The State of the Organs of the Female Reproductive System after a 5-Day "Dry" Immersion

The impact of weightlessness on the female reproductive system remains poorly understood, although deep space exploration is impossible without the development of effective measures to protect women's health. The purpose of this work was to study the effect of a 5-day "dry" immersion on the state of the reproductive system of female subjects. On the fourth day of the menstrual cycle after immersion, we observed an increase in inhibin B of 35% (p < 0.05) and a decrease in luteinizing hormone of 12% (p < 0.05) and progesterone of 52% (p < 0.05) compared with the same day before immersion. The size of the uterus and the thickness of the endometrium did not change. On the ninth day of the menstrual cycle after immersion, the average diameters of the antral follicles and the dominant follicle were, respectively, 14% and 22% (p < 0.05) higher than before. The duration of the menstrual cycle did not change. The obtained results may indicate that the stay in the 5-day "dry" immersion, on the one hand, can stimulate the growth of the dominant follicle, but, on the other hand, can cause functional insufficiency of the corpus lutea.

Local regulation of antral follicle development and ovulation in monovulatory species

The identification of mutations in the genes encoding bone morphogenetic protein 15 (BMP15) and growth and differentiation factor 9 (GDF9) associated with phenotypes of sterility or increased ovulation rate in sheep aroused interest in the study of the role of local factors in preantral and antral folliculogenesis in different species. An additive mutation in the BMP15 receptor, BMPR1b, which determines an increase in the ovulatory rate, has been introduced in several sheep breeds to increase the number of lambs born. Although these mutations indicate extremely relevant functions of these factors, the literature data on the regulation of the expression and function of these proteins and their receptors are very controversial, possibly due to differences in experimental models. The present review discusses the published data and preliminary results obtained by our group on the participation of local factors in the selection of the dominant follicle, ovulation, and follicular atresia in cattle, focusing on transforming growth factors beta and their receptors. The study of the expression pattern and the functionality of proteins produced by follicular cells and their receptors will allow increasing the knowledge about this local system, known to be involved in ovarian physiopathology and with the potential to promote contraception or increase the ovulation rate in mammals.

Effect of Lactobacillus plantarum on folliculogenesis in deep frying oil-fed rats

Today, the tendency towards Western World diet characterized by a high consumption of Deep Frying Oil (DFO), as well as female infertility has increased. On the other hand, probiotics are living microorganisms that can benefit human health. Therefore, this study aimed to investigate the effect of a probiotic treatment (Lactobacillus plantarum) on the process of follicular growth in rats fed with DFO. Twenty adult female Wistar rats were divided into four groups: control, DFO treatment, DFO treatment group receiving probiotic and the healthy group receiving probiotic for one month. After blood sampling and dissection, ovarian tissue was examined for the number of ovarian follicles at different stages. In addition, the expression of Bmp15 (Gdf-9b) and Gdf9 genes was assessed by the real-time PCR method. The ELISA test was also used to measure hormonal changes (LH and FSH). Data showed that rats treated with DFO had a significant decrease in follicle numbers, hormone levels and Bmp15 and Gdf9 gene expression. Moreover, the number of atretic follicles was increased. Treatment of rats with the probiotic reduced the observed side effects of DFO. Thus, treatments of rats with the probiotic mitigated some of the observed side effects of DFO. An increase in primordial follicles and a reduction of atretic follicles was indicated compared to the DFO group (P ≤ 0.001). Lactobacillus plantarum could reduce the detrimental effects of DFO on folliculogenesis through its beneficial effects.

Metzincin metalloproteases in PGC migration and gonadal sex conversion

Development of a functional gonad includes migration of primordial germ cells (PGCs), differentiations of somatic and germ cells, formation of primary follicles or spermatogenic cysts with somatic gonadal cells, development and maturation of gametes, and subsequent releasing of mature germ cells. These processes require extensive cellular and tissue remodeling, as well as broad alterations of the surrounding extracellular matrix (ECM). Metalloproteases, including MMPs (matrix metalloproteases), ADAMs (a disintegrin and metalloproteinases), and ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs), are suggested to have critical roles in the remodeling of the ECM during gonad development. However, few research articles and reviews are available on the functions and mechanisms of metalloproteases in remodeling gonadal ECM, gonadal development, or gonadal differentiation. Moreover, most studies focused on the roles of transcription and growth factors in early gonad development and primary sex determination, leaving a significant knowledge gap on how differentially expressed metalloproteases exert effects on the ECM, cell migration, development, and survival of germ cells during the development and differentiation of ovaries or testes. We will review gonad development with focus on the evidence of metalloprotease involvements, and with an emphasis on zebrafish as a model for studying gonadal sex differentiation and metalloprotease functions.

Genes linked with early menopause and the pathogenesis of its associated diseases: a systematic review

Background

Menopause is a biological process when a woman’s reproductive capability is no longer functional. A naturally or artificially caused premenopausal is known as early menopause occurs between the ages 40–45, which substantially impacts fertility and disease influenced by genetic plus environmental factors and their interactions. Women in early menopause are at greater risk of cardiovascular disease, general mortality, neurological disorders, osteoporosis, mental illness, and other problems.

Main body

A PubMed search of the electronic literature database yielded articles on early menopause and disease etiology. Several unique genes were identified, such as ESR1, ESR2, CYP1B1, BRSK1, HK3, andTMEM150B are associated with early menopause, and research focused on case-control, cohort, and cross-sectional studies are finding novel predisposition loci for early menopause.

Conclusion

The current study’s focus is to understand better the genetic aspects of early menopause. This knowledge will help researchers enhance EM etiology and identify biomarkers that may detect early development of the disease, allowing women at risk to begin family planning earlier.

Two Synthetic Peptides Corresponding to the Human Follicle-Stimulating Hormone β-Subunit Promoted Reproductive Functions in Mice

A follicle stimulating hormone (FSH) is widely used in the assisted reproduction and a synthetic peptide corresponding to a receptor binding region of the human (h) FSH-β-(34−37) (TRDL) modulated reproduction. Furthermore, a 13-amino acid sequence corresponding to hFSH-β-(37−49) (LVYKDPARPKIQK) was recently identified as the receptor binding site. We hypothesized that the synthetic peptides corresponding to hFSH-β-(37−49) and hFSH-β-(34−49), created by merging hFSH-β-(34−37) and hFSH-β-(37−49), modulate the reproductive functions, with the longer peptide being more biologically active. In male or female prepubertal mice, a single injection of 200 μg/g BW ip of hFSH-β-(37−49) or hFSH-β-(34−49) hastened (p < 0.05) puberty, whereas the same treatments given daily for 4 d promoted (p < 0.05) the gonadal steroidogenesis and gamete formation. In addition of either peptide to the in vitro cell cultures, promoted (p < 0.05) the proliferation of primary murine granulosa cells and the estradiol production by upregulating the expression of Ccnd2 and Cyp19a1, respectively. In adult female mice, 200 μg/g BW ip of either peptide during diestrus antagonized the FSH-stimulated estradiol increase and uterine weight gain during proestrus. Furthermore, hFSH-β-(34−49) was a more potent (p < 0.05) reproductive modulator than hFSH-β-(37−49), both in vivo and in vitro. We concluded that hFSH-β-(37−49) and especially hFSH-β-(34−49), have the potential for reproductive modulation.

Altered Expression of GDF9 and BMP15 Genes in Granulosa Cells of Diminished Ovarian Reserve Patients: A Case-Control Study

OBJECTIVE

Diminished ovarian reserve (DOR) is a challenging issue encountered during assisted reproductive technology. Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) belong to the transforming growth factor-beta (TGF-β) superfamily which are essential for folliculogenesis. We aimed to the evaluation of the GDF9 and BMP15 expression in the granulosa cells (GCs) of DOR patients.

MATERIALS AND METHODS

This case-control study included 14 women with DOR and 12 controls, who were between 28- 40 years of age undergoing controlled ovarian stimulation with a gonadotropin releasing hormone (GnRH) antagonist protocol. DOR patients were selected by the Bologna criteria. The GCs were extracted from the aspirated follicular fluids and RNA isolated from this. The fold change of gene expressions was assessed by real-time polymerase chain reaction (PCR).

RESULTS

GDF9 expression in patients was 0.23 times lower than the control group, which was significant (P<0.0001). BMP15 expression in patients was 0.32 times lower than the control group, which was significant (P<0.0001). The number of archived oocytes, MII, and two pronuclei (PN) embryos was higher in the control group and these differences were statistically significant (P<0.05).

CONCLUSION

Given that GDF9 and BMP15 are specifically involved during follicular recruitmen., we expect expression of these two genes in DOR patients which is greatly reduced by reducing follicular reserve.

Ramelteon Reduces Oxidative Stress by Maintenance of Lipid Homeostasis in Porcine Oocytes

This study aimed to determine the underlying mechanism of ramelteon on the competence of oocyte and subsequent embryo development in pigs during in vitro maturation (IVM). Our results showed that the cumulus expansion index was significantly lower in the control group compared to the ramelteon groups (p < 0.05). Moreover, supplementation of 10−11 and 10−9 M ramelteon significantly increased the cumulus expansion and development-related genes expression, and reduced apoptosis in cumulus cells (p < 0.05). In oocytes, the nuclear maturation rate was significantly improved in 10−11, 10−9, and 10−7 M ramelteon groups compared to the control (p < 0.05). Additionally, the level of intracellular GSH was significantly increased and ROS was significantly decreased in ramelteon-supplemented groups, and the gene expression of oocyte development and apoptosis were significantly up- and down-regulated by 10−11 and 10−9 M ramelteon (p < 0.05), respectively. The immunofluorescence results showed that the protein levels of GDF9, BMP15, SOD1, CDK1, and PGC1α were significantly increased by 10−11 M ramelteon compared to the control (p < 0.05). Although there was no significant difference in cleavage rate, the blastocyst formation rate, total cell numbers, and hatching/-ed rate were significantly improved in 10−11 M ramelteon group compared to the control (p < 0.05). Furthermore, embryo development, hatching, and mitochondrial biogenesis-related genes were dramatically up-regulated by 10−11 M ramelteon (p < 0.05). In addition, the activities of lipogenesis and lipolysis in oocytes were dramatically increased by 10−11 M ramelteon compared to the control (p < 0.05). In conclusion, supplementation of 10−11 M ramelteon during IVM improved the oocyte maturation and subsequent embryo development by reducing oxidative stress and maintenance of lipid homeostasis.

Strategies for Mammalian Mesenchymal Stem Cells Differentiation into Primordial Germ Cell-Like Cells: A Review

Primordial germ cells develop into oocytes and sperm cells. These cells are useful resources in reproductive biology and regenerative medicine. The mesenchymal stem cells (MSCs) have been examined for in vitro production of primordial germ cell-like cells. This study aimed to summarize the existing protocols for MSCs differentiation into primordial germ cell-like cells (PGLCs). In the limited identified studies, various models of mesenchymal stem cells, including those derived from adipose tissue, bone marrow, and Wharton's jelly, have been successfully differentiated into primordial germ cell-like cells. Although the protocols of specification induction are basically very similar, they have been adjusted to the mesenchymal cell type and the species of origin. The availability of MSCs has made it possible to customize conditions for their differentiation into primordial germ cell-like cells in several models, including humans. Refining germ cell-related signaling pathways during induced differentiation of MSCs will help define extension to the protocols for primordial germ cell-like cells production.

Effects of active immunization against a 13-amino acid receptor-binding epitope of FSHβ on fertility regulation in female mice

Follicle-stimulating hormone (FSH) is crucial for ovarian folliculogenesis and thus essential for female fertility. Here, we developed a novel FSH vaccine based on the tandem of a 13-amino acid receptor-binding epitope of FSHβ (FSHβ13AA-T) and used a mouse model to test its efficacy in female fertility regulation. Compared to placebo-immunized controls, FSHβ13AA-T vaccination: induced a marked (P < 0.05) antibody generation; reduced (P < 0.05) serum concentrations of FSH, inhibin B and 17β-estradiol; disrupted (P < 0.05) normal estrous cyclicity; delayed (P = 0.08) establishment of pregnancy; blocked (P < 0.05) folliculogenesis; and reduced (P < 0.05) litter size. Mechanistically, FSH vaccination reduced (P < 0.05) ovarian estrogen production by decreasing Lhcgr, Cyp19a1 and HSD3β1 expression, and suppressed ovarian follicular development by decreasing ovarian Fshr, Inhα, Foxo3a, Bmp15 and Cdh1 expression. Overall, vaccination of female mice with FSHβ13AA-T substantially disrupted FSH-dependent ovarian steroidogenesis and folliculogenesis, and caused subfertility. Therefore, vaccines based on FSHβ13AA-T have potential as anti-fertility/contraceptive agents in females.

An Investigation of the Effects of Chronic Zonisamide, Sultiam, Lacosamide, Clobazam, and Rufinamide Antiseizure Drugs on Foliculogenesis in Ovarian Tissue in Prepubertal Non-Epileptic Rats

We aimed to determine the morphological and histological effects of zonisamide, sultiam, lacosamide, clobazam, and rufinamide on ovarian folliculogenesis in rats. Sixty female Wistar rats were equally divided into 6 experimental groups, including control group, zonisamide, sultiam, lacosamide, clobazam, and rufinamide were administered by gavage for 90 days. According to the daily vaginal smears of the rats in the proestrus and diester phases of the estrus cycle, their ovaries were removed and placed in the fixation solution. Immunohistochemical and apoptosis staining protocols were applied. The number of healthy follicles in the control group was found to be statistically significantly higher when compared to the antiseizure drug groups (p<0.001). The number of corpus luteum was found to be statistically significantly lower in the control group when compared with the anti-seizure drug groups (p<0.001). There was a significant difference in the number of TUNEL positive apoptotic follicles between the control and drug groups (p<0.001). There was a significant difference in the number of TUNEL positive apoptotic follicles between the control and drug groups (p<0.001). HSCORE, immunohistochemical EGF, IGF-1 and GDF-9 staining, a very strong immunoreaction was observed in the ovarian multilaminar primary follicle granulosa cells and oocytes in the control group (p<0.001), and an immunoreaction ranging from weak to medium was observed in the antiseizure drug groups. Long-term anti-seizure drug therapy with zonisamide, sultiam, lacosamide, clobazam, and rufinamide from prepubertal to adulthood causes apoptosis and disruption of folliculogenesis in the ovarian follicles of nonepileptic rats.

Chromatin Accessibility Analysis from Fresh and Cryopreserved Human Ovarian Follicles

Understanding how gene regulatory elements influence ovarian follicle development has important implications in clinically relevant settings. This includes understanding decreased fertility with age and understanding the short-lived graft function commonly observed after ovarian tissue cryopreservation and subsequent autologous transplantation as a fertility preservation treatment. The Assay for Transposase Accessible Chromatin by sequencing (ATAC-seq) is a powerful tool to identify distal and proximal regulatory elements important for activity-dependent gene regulation and hormonal and environmental responses such as those involved in germ cell maturation and human fertility. Original ATAC protocols were optimized for fresh cells, a major barrier to implementing this technique for clinical tissue samples which are more often than not frozen and stored. While recent advances have improved data obtained from stored samples, this technique has yet to be applied to human ovarian follicles, perhaps due to the difficulty in isolating follicles in sufficient quantities from stored clinical samples. Further, it remains unknown whether the process of cryopreservation affects the quality of the data obtained from ovarian follicles. Here, we generate ATAC-seq data sets from matched fresh and cryopreserved human ovarian follicles. We find that data obtained from cryopreserved samples are of reduced quality but consistent with data obtained from fresh samples, suggesting that the act of cryopreservation does not significantly affect biological interpretation of chromatin accessibility data. Our study encourages the use of this method to uncover the role of chromatin regulation in a number of clinical settings with the ultimate goal of improving fertility.

Long-Term Changes in Ovarian Follicles of Gilts Exposed Neonatally to Methoxychlor: Effects on Oocyte-Derived Factors, Anti-Müllerian Hormone, Follicle-Stimulating Hormone, and Cognate Receptors

In this paper, we investigated the effects of neonatal exposure to methoxychlor (MXC), a synthetic organochlorine used as an insecticide with estrogenic, antiestrogenic, and antiandrogenic activities on ovarian follicles of adult pigs. Piglets were injected with MXC (20 μg/kg body weight) or corn oil (controls) from postnatal Day 1 to Day 10 (n = 5 per group). Then, mRNA expression, protein abundance and immunolocalization of growth and differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15), anti-Müllerian hormone (AMH) and cognate receptors (ACVR1, BMPR1A, BMPR1B, TGFBR1, BMPR2, and AMHR2), as well as FSH receptor (FSHR) were examined in preantral and small antral ovarian follicles of sexually mature gilts. The plasma AMH and FSH levels were also assessed. In preantral follicles, neonatal exposure to MXC increased GDF9, BMPR1B, TGFBR1, and BMPR2 mRNAs, while the levels of AMH and BMP15 mRNAs decreased. In addition, MXC also decreased BMP15 and BMPR1B protein abundance. Regarding small antral follicles, neonatal exposure to MXC upregulated mRNAs for BMPR1B, BMPR2, and AMHR2 and downregulated mRNAs for AMH, BMPR1A, and FSHR. MXC decreased the protein abundance of AMH, and all examined receptors in small antral follicles. GDF9 and BMP15 were immunolocalized in oocytes and granulosa cells of preantral follicles of control and treated ovaries. All analyzed receptors were detected in the oocytes and granulosa cells of preantral follicles, and in the granulosa and theca cells of small antral follicles. The exception, however, was FSHR, which was detected only in the granulosa cells of small antral follicles. In addition, MXC decreased the plasma AMH and FSH concentrations. In conclusion, the present study may indicate long-term effects of neonatal MXC exposure on GDF9, BMP15, AMH, and FSH signaling in ovaries of adult pigs. However, the MXC effects varied at different stages of follicular development. It seems that neonatal MXC exposure may result in accelerated initial recruitment of ovarian follicles and impaired cyclic recruitment of antral follicles.

Novel bone morphogenetic protein 15 (BMP15) gene variants implicated in premature ovarian insufficiency

BACKGROUND

Bone morphogenetic protein 15 (BMP15) is expressed in oocytes and plays a crucial role in the reproduction of mono-ovulating species. In humans, BMP15 gene mutations lead to imperfect protein function and premature ovarian insufficiency. Here we investigated the BMP15 gene variants in a population of Iranian women with premature ovarian insufficiency. We conducted predictive bioinformatics analysis to further study the outcomes of BMP15 gene alterations.

METHODS

Twenty-four well-diagnosed premature ovarian insufficiency cases with normal karyotype participated in this study. The entire coding sequence and exon-intron junctions of the BMP15 gene were analyzed by direct sequencing. In-silico analysis was applied using various pipelines integrated into the Ensembl Variant Effect Predictor online tool. The clinical interpretation was performed based on the approved guidelines.

RESULTS

By gene screening of BMP15, we discovered p.N103K, p.A180T, and p.M184T heterozygous variants in 3 unrelated patients. The p.N103K and p.M184T were not annotated on gnomAD, 1000 Genome and/or dbSNP. These mutations were not identified in 800 Iranians whole-exome sequencing that is recorded on Iranom database. We identified the p.N103K variant in a patient with secondary amenorrhea at the age of 17, elevated FSH and atrophic ovaries. The p.M184T was detected in a sporadic case with atrophic ovaries and very high FSH who developed secondary amenorrhea at the age of 31.

CONCLUSIONS

Here we newly identified p.N103K and p.M184T mutation in the BMP15 gene associated with idiopathic premature ovarian insufficiency. Both mutations have occurred in the prodomain region of protein. Despite prodomain cleavage through dimerization, it is actively involved in the mature protein function. Further studies elucidating the roles of prodomain would lead to a better understanding of the disease pathogenesis.