Identification of a mutation in GDF9 as a novel cause of diminished ovarian reserve in young women

Understanding the Mechanisms of Diminished Ovarian Reserve: Insights from Genetic Variants and Regulatory Factors

Delaying childbearing age has become a trend in modern times, but it has also led to a common challenge in clinical reproductive medicine-diminished ovarian reserve (DOR). Since the mechanism behind DOR is unknown and its clinical features are complex, physicians find it difficult to provide targeted treatment. Many factors affect ovarian reserve function, and existing studies have shown that genetic variants, upstream regulatory genes, and changes in protein expression levels are present in populations with reduced ovarian reserve function. However, existing therapeutic regimens often do not target the genetic profile for more individualized treatment. In this paper, we review the types of genetic variants, mutations, altered expression levels of microRNAs, and other related factors and their effects on the regulation of follicular development, as well as altered DNA methylation. We hope this review will have significant implications for the future treatment of individuals with reduced ovarian reserve.

GDF9His209GlnfsTer6/S428T and GDF9Q321X/S428T bi-allelic variants caused female subfertility with defective follicle enlargement

BACKGROUND

Antral follicles consist of an oocyte cumulus complex surrounding by somatic cells, including mural granulosa cells as the inner layer and theca cells as the outsider layer. The communications between oocytes and granulosa cells have been extensively explored in in vitro studies, however, the role of oocyte-derived factor GDF9 on in vivo antral follicle development remains elusive due to lack of an appropriate animal model. Clinically, the phenotype of GDF9 variants needs to be determined.

METHODS

Whole-exome sequencing (WES) was performed on two unrelated infertile women characterized by an early rise of estradiol level and defect in follicle enlargement. Besides, WES data on 1,039 women undergoing ART treatment were collected. A Gdf9Q308X/S415T mouse model was generated based on the variant found in one of the patients.

RESULTS

Two probands with bi-allelic GDF9 variants (GDF9His209GlnfsTer6/S428T, GDF9Q321X/S428T) and eight GDF9S428T heterozygotes with normal ovarian response were identified. In vitro experiments confirmed that these variants caused reduction of GDF9 secretion, and/or alleviation in BMP15 binding. Gdf9Q308X/S415T mouse model was constructed, which recapitulated the phenotypes in probands with abnormal estrogen secretion and defected follicle enlargement. Further experiments in mouse model showed an earlier expression of STAR in small antral follicles and decreased proliferative capacity in large antral follicles. In addition, RNA sequencing of granulosa cells revealed the transcriptomic profiles related to defective follicle enlargement in the Gdf9Q308X/S415T group. One of the downregulated genes, P4HA2 (a collagen related gene), was found to be stimulated by GDF9 protein, which partly explained the phenotype of defective follicle enlargement.

CONCLUSIONS

GDF9 bi-allelic variants contributed to the defect in antral follicle development. Oocyte itself participated in the regulation of follicle development through GDF9 paracrine effect, highlighting the essential role of oocyte-derived factors on ovarian response.

Inactivation of growth differentiation factor 9 blocks folliculogenesis in pigs†

Growth differentiation factor 9 (GDF9) is a secreted protein belonging to the transforming growth factor beta superfamily and has been well characterized for its role during folliculogenesis in the ovary. Although previous studies in mice and sheep have shown that mutations in GDF9 disrupt follicular progression, the exact role of GDF9 in pigs has yet to be elucidated. The objective of this study was to understand the role of GDF9 in ovarian function by rapidly generating GDF9 knockout (GDF9-/-) pigs by using the CRISPR/Cas9 system. Three single-guide RNAs designed to disrupt porcine GDF9 were injected with Cas9 mRNA into zygotes, and blastocyst-stage embryos were transferred into surrogates. One pregnancy was sacrificed on day 100 of gestation to investigate the role of GDF9 during oogenesis. Four female fetuses were recovered with one predicted to be GDF9-/- and the others with in-frame mutations. All four had fully formed oocytes within primordial follicles, confirming that knockout of GDF9 does not disrupt oogenesis. Four GDF9 mutant gilts were generated and were grown past puberty. One gilt was predicted to completely lack functional GDF9 (GDF9-/-), and the gilt never demonstrated standing estrus and had a severely underdeveloped reproductive tract with large ovarian cysts. Further examination revealed that the follicles from the GDF9-/- gilt did not progress past preantral stages, and the uterine vasculature was less extensive than the control pigs. By using the CRISPR/Cas9 system, we demonstrated that GDF9 is a critical growth factor for proper ovarian development and function in pigs.

Whole exome sequencing reveals novel variants associated with diminished ovarian reserve in young women

Background: Diminished ovarian reserve is one of the most important causes of female infertility. In the etiology study of DOR, besides age, it is known that chromosomal abnormality, radiotherapy, chemotherapy and ovarian surgery can result in DOR. For young women without obvious risk factors, gene mutation should be considered as a possible cause. However, the specific molecular mechanism of DOR has not been fully elucidated.

Methods: In order to explore the pathogenic variants related to DOR, twenty young women under 35 years old affected by DOR without definite factors damaging ovarian reserve were recruited as the research subjects, and five women with normal ovarian reserve were recruited as the control group. Whole exome sequencing was applied as the genomics research tool.

Results: As a result, we obtained a set of mutated genes that may be related to DOR, where the missense variant on GPR84 was selected for further study. It is found that GPR84Y370H variant promotes the expression of proinflammatory cytokines (TNF-α, IL12B, IL-1β) and chemokines (CCL2, CCL5), as well as the activation of NF-κB signaling pathway.

Conclusion: In conclusion, GPR84Y370H variant was identified though analysis for WES results of 20 DOR patients. The deleterious variant of GPR84 could be the potential molecular mechanism of non-age-related pathological DOR through its role in promoting inflammation. The findings of this study can be used as a preliminary research basis for the development of early molecular diagnosis and treatment target selection of DOR.

Decreased GDF9 and BMP15 in follicle fluid and granulosa cells and outcomes of IVF-ET among young patients with low prognosis

PURPOSE

To analyze the level of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in follicle fluid (FF) and granulosa cells (GCs) derived from young patients with low prognosis for in vitro fertilization and embryo transfer (IVF-ET) treatment.

METHODS

A prospective cohort study was carried out by enrolling 52 young patients with low prognosis according to the POSEIDON classification group 3 (low prognosis group) and 51 young patients with normal ovarian reserve (control group). The concentration of the GDF9 and BMP15 proteins in FF was determined by enzyme-linked immunosorbent assay. The mRNA level of the GDF9 and BMP15 in the GCs was measured by quantitative real-time PCR.

RESULTS

The concentration of GDF9 (1026.72 ± 159.12 pg/mL vs. 1298.06 ± 185.41 pg/mL) and BMP15 (685.23 ± 143.91 pg/mL vs. 794.37 ± 81.79 pg/mL) in FF and the mRNA level of GDF9 and BMP15 in the GCs and the live birth rate per treatment cycle started (30.77% vs. 50.98%) and oocytes retrieved (4.25 ± 1.91 vs.12.04 ± 4.24) were significantly lower, whereas the canceled cycle rate was significantly higher (9.62% vs. 0) in the low prognosis group compared with the control group (P < 0.05). The expression of GDF9 and BMP15 in the ovary was positively correlated with live birth (P < 0.05).

CONCLUSION

The expression of GDF9 and BMP15 in the ovary was decreased in young patients with low prognosis accompanied by a poorer outcome of IVF-ET treatment.

TRIAL REGISTRATION

ChiCTR1800016107 (Chinese Clinical Trial Registry), May 11, 2018. ( http://www.chictr.org.cn/edit.aspx?pid=27216&htm=4 ).

Loss of growth differentiation factor 9 causes an arrest of early folliculogenesis in zebrafish-A novel insight into its action mechanism

Growth differentiation factor 9 (GDF9) was the first oocyte-specific growth factor identified; however, most information about GDF9 functions comes from studies in the mouse model. In this study, we created a mutant for Gdf9 gene (gdf9-/-) in zebrafish using TALEN approach. The loss of Gdf9 caused a complete arrest of follicle development at primary growth (PG) stage. These follicles eventually degenerated, and all mutant females gradually changed to males through sex reversal, which could be prevented by mutation of the male-promoting gene dmrt1. Interestingly, the phenotypes of gdf9-/- could be rescued by simultaneous mutation of inhibin α (inha-/-) but not estradiol treatment, suggesting a potential role for the activin-inhibin system or its signaling pathway in Gdf9 actions. In gdf9-null follicles, the expression of activin βAa (inhbaa), but not βAb (inhbab) and βB (inhbb), decreased dramatically; however, its expression rebounded in the double mutant (gdf9-/-;inha-/-). These results indicate clearly that the activation of PG follicles to enter the secondary growth (SG) requires intrinsic factors from the oocyte, such as Gdf9, which in turn works on the neighboring follicle cells to trigger follicle activation, probably involving activins. In addition, our data also support the view that estrogens are not involved in follicle activation as recently reported.

RNA-methyltransferase Nsun5 controls the maternal-to-zygotic transition by regulating maternal mRNA stability

BACKGROUND

RNA modification-induced ovarian dysgenesis appears to be necessary for ovary development. However, how m⁵ C (5-methylcytosine)-coordinating modificatory transcripts are dynamically regulated during oogenesis, and ovarian development is unknown. The purpose of this study was to determine whether NOP2/Sun RNA methyltransferase 5 (Nsun5) deletion leads to suppression of ovarian function and arrest of embryonic development. The regulation of mRNA decay and stability by m⁵ C modification is essential at multiple stages during the maternal-to-zygotic (MZT) transition.

METHODS

Mouse ovaries and oocytes with Nsun5^KO and the KGN cell line were subjected to m⁵ C identification, alternative splicing analysis and protein expression. BS-m⁵ C-seq, real-time polymerase chain reaction, Western blot, immunofluorescence and actinomycin D treatment assays were used. In particular, BS-m⁵ C-seq revealed a dynamic pattern of m⁵ C sites and genes in the ovaries between Nsun5^KO and WT mice at the 2-month and 6-month stages. Diverse bioinformatic tools were employed to identify target genes for Nsun5.

RESULTS

Here, a maternal mRNA stability study showed that deletion of the m⁵ C methyltransferase Nsun5 obstructs follicular development and ovarian function, which leads directly to inhibition of embryogenesis and embryo development. Dynamic analysis of m⁵ C revealed that the level of m⁵ C decreased in a time-dependent manner after Nsun5 knockout. Regarding the molecular mechanism, we found that Nsun5 deficiency caused a m⁵ C decline in the exon and 3'UTR regions that influenced the translation efficiency of Mitotic arrest deficient 2 like 2 (MAD2L2) and Growth differentiation factor 9 (GDF9) in the ovary. Mechanistic investigation of alternative splicing indicated that Nsun5^KO triggers aberrant events in the exon region of Brd8.

CONCLUSIONS

Nsun5 loss arrests follicular genesis and development in ovarian aging, indicating that Nsun5/m⁵ C-regulated maternal mRNA stabilization is essential for MZT transition.

Concentrations of oocyte secreted GDF9 and BMP15 decrease with MII transition during human IVM

BACKGROUND

The suggested effects of the oocyte secreted GDF9 and BMP15 growth factors on oocyte maturation are currently based on recombinant proteins, and little is known about native GDF9 and BMP15 in humans.

METHODS

Human immature cumulus-oocyte complexes (COCs) obtained in connection with ovarian tissue cryopreservation (OTC) underwent in vitro maturation (IVM). Oocyte-produced GDF9 and BMP15 were detected in COCs using immunofluorescence, and in fresh GV oocytes and in GV and MII oocytes after IVM by western blot. Concentrations of GDF9, BMP15 homodimers, and GDF9/BMP15 heterodimer in spent media after IVM were measured by ELISA. The relative expression of seven genes from the GDF9 and BMP15 signaling pathways (BMPR2, ALK5, ALK6, SMAD1, SMAD2, SMAD3, and SMAD5) was evaluated in fresh cumulus cells (before IVM) and in cumulus cells from GV and MII oocytes after IVM by RT-qPCR.

RESULTS

We detected native pro-mature GDF9 and BMP15 in human oocytes with molecular weights (Mw) of 47 kDa and 43 kDa, respectively. Concentrations of GDF9 and BMP15 in spent media after IVM were detected in 99% and 64% of the samples, respectively. The GDF9/BMP15 heterodimer was detected in 76% of the samples. Overall, the concentration of GDF9 was approximately 10-times higher than BMP15. The concentrations of both GDF9 and BMP15 were significantly lower in spent medium from MII oocytes than in media from oocytes that remained at the GV stage. Concentrations of the GDF9/BMP15 heterodimer did not differ between GV and MII oocytes. Furthermore, BMPR2, SMAD3, and SMAD5 were significantly upregulated in cumulus cells from MII oocytes, indicating that both GDF9 and BMP15 signaling were active during oocyte meiotic resumption in vitro.

CONCLUSION

These data suggest that the driving mechanisms for oocyte nuclear maturation may involve both GDF9 and BMP15 homodimers, while the role of the GDF9/BMP15 heterodimer is questionable.

Intrafollicular Concentrations of the Oocyte-secreted Factors GDF9 and BMP15 Vary Inversely in Polycystic Ovaries

CONTEXT

The oocyte-secreted factors growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) play essential roles in follicle development and oocyte maturation, and aberrant regulation might contribute to the pathogenesis of polycystic ovary syndrome.

OBJECTIVE

Are there measurable differences in concentrations of GDF9, BMP15, and the GDF9/BMP15 heterodimer in small antral follicle fluids from women with and without polycystic ovaries (PCO)?

DESIGN AND SETTING

Follicle fluids (n = 356) were collected from 4- to 11-mm follicles in unstimulated ovaries of 87 women undergoing ovarian tissue cryopreservation for fertility preservation.

PATIENTS

Twenty-seven women with PCO were identified and 60 women without PCO-like characteristics (non-PCO women) were matched according to age and follicle size.

MAIN OUTCOME MEASURES

Intrafollicular concentrations of GDF9, BMP15, GDF9/BMP15 heterodimer, anti-Mullerian hormone (AMH), inhibin-A and -B, total inhibin, activin-B and -AB, and follistatin were measured using enzyme-linked immunosorbent assays.

RESULTS

The detectability of GDF9, BMP15, and the GDF9/BMP15 heterodimer were 100%, 94.4%, and 91.5%, respectively, and concentrations were significantly negatively correlated with increasing follicle size (P < 0.0001). GDF9 was significantly higher in women with PCO (PCO: 4230 ± 189 pg/mL [mean ± SEM], n = 188; non-PCO: 3498 ± 199 pg/mL, n = 168; P < 0.03), whereas BMP15 was lower in women with PCO (PCO: 431 ± 40 pg/mL, n = 125; non-PCO: 573 ± 55 pg/mL, n = 109; P = 0.10), leading to a significantly higher GDF9:BMP15 ratio in women with PCO (P < 0.01). Significant positive associations between BMP15 and AMH, activins, and inhibins in non-PCO women switched to negative associations in women with PCO.

CONCLUSIONS

Intrafollicular concentrations of GDF9 and BMP15 varied inversely in women with PCO reflecting an aberrant endocrine environment. An increased GDF9:BMP15 ratio may be a new biomarker for PCO.

Chicken ovarian follicles morphology and growth differentiation factor 9 gene expression in chicken ovarian follicles: review

Ovary follicular development is a progressive system from the beginning of small cortical follicles to the ovulation of hierarchical follicles. The review was conducted to provide information on the indigenous chickens commonly used for egg production, chicken ovarian follicles morphology and expression of growth differentiation factor 9 (GDF9) gene in ovarian follicles and its relationship with egg production. The research databases used in the study include google scholar, Science Direct, PubMed, JSTOR and Cambridge Core. Google, Yahoo and Baidu search engines were used to search the information. In this study, the papers selected for use were original research articles and reviews to ensure that the information used was from research results. Besides, only recent English papers, 2010-2021, were used. The keywords used to search for articles were chicken ovarian follicles, ovarian morphology and GDF9 gene expression. The documents showed that pre-hierarchical follicles include many small and large white follicles, which are about 2-5mm in diameter and 5 to 6 small yellow follicles (SYF) that are about 5-10mm in diameter. Preovulatory follicles are about five to six in number and above 10mm in diameter, with the sizes from F6 to F1, with F1 as the largest follicle. Further, the studies revealed that GDF9 gene mRNA is expressed in the highest concentration in small yellow follicles and other studies reported that the expression of GDF9 gene has been found in follicles of the primary to preovulatory stages in chickens. This review concludes that the GDF9 gene expression is mainly throughout follicular growth and it stimulates the proliferation of pre-hierarchical granulosa cells. The increased egg production in chickens depends on progressive developmental stages and the growth of ovarian follicles.

Association of FSHR, LH, LHR, BMP15, GDF9, AMH, and AMHR polymorphisms with poor ovarian response in patients undergoing in vitro fertilization

Objective:

This paper aimed to assess the correlation between LH, LHR, GDF9, FSHR, AMH, AMHR2, and BMP15 polymorphisms, which are related to follicular development, and decreased ovarian response in women undergoing controlled ovarian hyperstimulation (COH) for IVF.

Methods:

This age-matched case-control study included three or four controls per woman undergoing COH. Controls were women with normal ovarian response (NOR) and cases were women with poor ovarian response (POR) in oocyte retrieval (three or fewer oocytes). DNA was extracted from peripheral blood and potential associations with gene polymorphisms related to follicular development (LH, LHR, GDF9, FSHR, AMH, AMHR2, and BMP15) were analyzed.

Results:

Sixty-six patients were included, 52 in the NOR and 14 in the POR group. Two GDF9 polymorphisms were associated with follicular response after COH, one associated with POR - the presence of a mutant polymorphism in heterozygosis and homozygosis of the GDF9 398-39 (C to G) [23% NOR versus 68% POR (OR 4.01, CI 1.52-10.6, p=0.005)] - and another associated with protective response - the presence of normal homozygosis of GDF9 (C447T) [19.2% NOR versus 50% POR (OR 0.34, IC 0.14-0.84, p=0.019)]. No additional associations were found between the other analyzed polymorphisms and POR.

Conclusions:

This study found that GDF9 appears to play an important role in follicular development, whereas polymorphisms in its DNA chain may negatively affect ovarian reserve, such as 398-39 (C to G), or positively, as seen in C447T.

Forecasting early onset diminished ovarian reserve for young reproductive age women

PURPOSE

To investigate the biological networks associated with DOR in young women and the subsequent molecular impact on preimplantation embryos.

METHODS

Whole peripheral blood was collected from patients: young women presenting with diminished ovarian reserve (DOR) and age-matched young women with normal ovarian reserve. Maternal exome sequencing was performed on the NovaSEQ 6000 and sequencing validation was completed using Taqman® SNP Genotyping Assays. Blastocyst global methylome and transcriptome sequencing were also analyzed.

RESULTS

Exome sequencing revealed 730 significant DNA variants observed exclusively in the young DOR patients. Bioinformatic analysis revealed a significant impact to the Glucocorticoid receptor (GR) signaling pathway and each young DOR female had an average of 6.2 deleterious DNA variants within this pathway. Additional stratification based on patient age resulted in a cut-off at 31 years for young DOR discrimination. Embryonic global methylome sequencing resulted in only a very small number of total CpG sites with methylation alterations (1,775; 0.015% of total) in the DOR group. Additionally, there was no co-localization between these limited number of altered CpG sites and significant variants, genes, or pathways. RNA sequencing also resulted in no biologically significant transcription changes between DOR blastocysts and controls.

CONCLUSION

GR signaling DNA variants were observed in women with early-onset DOR potentially compromising oocyte production and quality. However, no significant downstream effects on biological processes appear to impact the resulting blastocyst. The ability to forecast premature DOR for young women may allow for earlier identification and clinical intervention for this patient population.

Age-related decline in the expression of GDF9 and BMP15 genes in follicle fluid and granulosa cells derived from poor ovarian responders

Background

Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) genes play important roles in folliculogenesis. Altered expression of the two have been found among patients with poor ovarian response (POR). In this prospective cohort study, we have determined the expression of the GDF9 and BMP15 genes in follicle fluid (FF) and granulosa cells (GCs) derived from poor ovarian responders grouped by age, and explored its correlation with the outcome of in vitro fertilization and embryo transfer (IVF-ET) treatment.

Methods

A total of 196 patients with POR were enrolled from a tertiary teaching hospital. The patients were diagnosed by the Bologna criteria and sub-divided into group A (< 35 year old), group B (35–40 year old), and group C (> 40 year old). A GnRH antagonist protocol was conducted for all patients, and FF and GCs were collected after oocyte retrieval. Expression of the GDF9 and BMP15 genes in the FF and GCs was determined with enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting.

Results

Compared with group C, groups A and B had significantly more two pronuclei (2PN) oocytes and transplantable embryos, in addition with higher rates of implantation and clinical pregnancy (P <  0.05). The expression level of GDF9 and BMP15 genes in the FF and GCs differed significantly among the three groups (P <  0.05), showing a trend of decline along with age. The ratio of GDF9/BMP15 mRNA levels were similar among the three groups (P > 0.05). The relative levels of GDF9 and BMP15 proteins in GCs have correlated with the relative mRNA levels in GCs and protein concentrations in FF (P <  0.05).

Conclusions

For poor ovarian responders, in particular those over 40, the expression of GDF9 and BMP15 is declined along with increased age and in accompany with poorer oocyte quality and IVF outcome, whilst the ratio of GDF9/BMP15 mRNA levels remained relatively constant.

Trial registration

Chinese Clinical Trial Registry Center (ChiCTR1800016107). Registered on 11 May 2018.

New insights into the genetic basis of premature ovarian insufficiency: Novel causative variants and candidate genes revealed by genomic sequencing

Ovarian deficiency, including premature ovarian insufficiency (POI) and diminished ovarian reserve (DOR), represents one of the main causes of female infertility. POI is a genetically heterogeneous condition but current understanding of its genetic basis is far from complete, with the cause remaining unknown in the majority of patients. The genes that regulate DOR have been reported but the genetic basis of DOR has not been explored in depth. Both conditions are likely to lie along a continuum of degrees of decrease in ovarian reserve. We performed genomic analysis via whole exome sequencing (WES) followed by in silico analyses and functional experiments to investigate the genetic cause of ovarian deficiency in ten affected women. We achieved diagnoses for three of them, including the identification of novel variants in STAG3, GDF9, and FANCM. We identified potentially causative FSHR variants in another patient. This is the second report of biallelic GDF9 and FANCM variants, and, combined with functional support, validates these genes as bone fide autosomal recessive "POI genes". We also identified new candidate genes, NRIP1, XPO1, and MACF1. These genes have been linked to ovarian function in mouse, pig, and zebrafish respectively, but never in humans. In the case of NRIP1, we provide functional support for the deleterious nature of the variant via SUMOylation and luciferase/β-galactosidase reporter assays. Our study provides multiple insights into the genetic basis of POI/DOR. We have further elucidated the involvement of GDF9, FANCM, STAG3 and FSHR in POI pathogenesis, and propose new candidate genes, NRIP1, XPO1, and MACF1, which should be the focus of future studies.

GDF9 polymorphisms: influence on ovarian response in women undergoing controlled ovarian hyperstimulation

OBJECTIVE

The study looked into the possible influence of GDF9 polymorphisms on ovarian response in women with a normal ovarian reserve undergoing controlled ovarian hyperstimulation for in vitro fertilization (IVF).

METHODS

This cross-sectional study included 67 women with normal ovarian reserve aged 30-39 years submitted to controlled ovarian hyperstimulation for IVF. We sequenced four polymorphisms in the GDF9 gene (C398G, C447T, G546A, and G646A) and analyzed their influence on follicular and oocyte outcomes.

RESULTS

The mutant allele C398G decreased the total number of follicles >17mm (6.49 vs. 4.33, p=0.001), total number of follicles (10.11 vs. 7.33, p=0.032), number of MII oocytes retrieved, and serum progesterone levels on trigger day. The C447T polymorphism was associated with a greater number of follicles between 12 and 14 mm on the day of r-hCG, while the G546A polymorphism was associated with lower serum progesterone levels on trigger day.

CONCLUSIONS

GDF9 gene polymorphisms C398G and C447T adversely affected ovarian response in women undergoing controlled ovarian hyperstimulation. These findings show that in addition to playing a role in the early stages of folliculogenesis, GDF9 polymorphisms have an important impact on the final stage of oocyte development.

Novel variants in women with premature ovarian function decline identified via whole-exome sequencing

PURPOSE

To investigate the potential etiologies of premature ovarian insufficiency (POI) and diminished ovarian reserve (DOR).

METHODS

Fourteen women with sporadic POI and 6 women with DOR were enrolled. We used whole-exome sequencing (WES) and bioinformatics analysis to identify variants in a subset of 599 selected POI candidate genes. The identified genes were subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and protein-protein interaction (PPI) network analyses to uncover key genes and pathways.

RESULTS

Among the 20 patients, 79 heterozygous variants were detected in 49 genes, which were classified as "likely pathogenic" or "variants of uncertain significance" according to the guidelines of the American College of Medical Genetics and Genomics. Most patients (17/20) carried two or more variants. Monoacylglycerol O-acyltransferase 1 mutations were found in six patients, and cytochrome P450 family 26 subfamily B member 1 and Bardet-Biedl syndrome 9 mutations were each found in four patients. Some variants were shared between DOR and POI. Enrichment analyses showed that the identified genes participate in key ovarian processes, such as follicular development, gonadal development, meiosis, Fanconi anemia, homologous recombination, and transforming growth factor β signaling. A PPI network revealed interactions between these proteins.

CONCLUSION

Premature ovarian function decline may be polygenic, and overlap exists between the genetic backgrounds of DOR and POI. WES and in silico analyses may be a useful clinical tool for etiological diagnosis and risk prediction for high-risk women in the future.

A Comparative Analysis of Oocyte Development in Mammals

Sexual reproduction requires the fertilization of a female gamete after it has undergone optimal development. Various aspects of oocyte development and many molecular actors in this process are shared among mammals, but phylogeny and experimental data reveal species specificities. In this chapter, we will present these common and distinctive features with a focus on three points: the shaping of the oocyte transcriptome from evolutionarily conserved and rapidly evolving genes, the control of folliculogenesis and ovulation rate by oocyte-secreted Growth and Differentiation Factor 9 and Bone Morphogenetic Protein 15, and the importance of lipid metabolism.

Live birth rate comparison of three controlled ovarian stimulation protocols for in vitro fertilization-embryo transfer in patients with diminished ovarian reserve after endometrioma cystectomy: a retrospective study

Background

Women with endometriosis and previous cystectomy may respond less well to gonadotropin stimulation, which results in fewer oocytes retrieved and poor pregnancy outcomes. Choosing an appropriate protocol for such populations is essential. This study involved an analysis of the effect of different controlled ovarian stimulation (COS) protocols on the clinical outcomes of in vitro fertilization-embryo transfer (IVF-ET) in women with diminished ovarian reserve (DOR) who underwent ovarian endometrioma cystectomy.

Methods

A total of 342 patients that underwent IVF-ET treatment at the Beijing Obstetrics and Gynecology Hospital from January 1, 2013 to April 30, 2018 were included in this retrospective study. The patients were distributed into three groups according to the COS protocols, namely prolonged GnRH-agonist (Group A, n = 113), GnRH-antagonist (Group B, n = 121), and long GnRH-agonist (Group C, n = 108). The clinical and laboratory parameters of the three protocols were analyzed and a logistic regression of clinical pregnancy and live births was conducted.

Results

There were no significant differences in the age, infertility duration, basic follicle stimulation hormone (FSH), luteinizing hormone (LH), or estradiol (E₂) levels as well as other baseline characteristics among groups (P > 0.05). The total gonadotrophin (Gn) dosage and duration tended to be less in the GnRH-antagonist group than in the others (P < 0.05). No significant differences were found in the implantation rate and clinical pregnancy rate among the groups, but the prolonged GnRH-agonist group showed the highest rates. In addition, no significant differences were present in the number of retrieved oocytes, oocyte fertilization rate, embryo utilization rate, live birth rate, abortion rate, ectopic pregnancy rate, or multiple pregnancy rate in the three groups (P > 0.05). Age had a significant effect on both clinical pregnancy and live birth.

Conclusion

For those DOR patients who had undergone ovarian endometriosis cystectomy, the prolonged GnRH-agonist protocol may achieve better clinical IVF-ET outcomes, but there were no significant differences from the other groups. The GnRH-antagonist protocol may reduce the cost and time of drug treatment. Age should be considered for its influence on pregnancy outcome. However, a larger sample size may be needed for further study.

Luteinizing Hormone Action in Human Oocyte Maturation and Quality: Signaling Pathways, Regulation, and Clinical Impact

The ovarian follicle luteinizing hormone (LH) signaling molecules that regulate oocyte meiotic maturation have recently been identified. The LH signal reduces preovulatory follicle cyclic nucleotide levels which releases oocytes from the first meiotic arrest. In the ovarian follicle, the LH signal reduces cyclic nucleotide levels via the CNP/NPR2 system, the EGF/EGF receptor network, and follicle/oocyte gap junctions. In the oocyte, reduced cyclic nucleotide levels activate the maturation promoting factor (MPF). The activated MPF induces chromosome segregation and completion of the first and second meiotic divisions. The purpose of this paper is to present an overview of the current understanding of human LH signaling regulation of oocyte meiotic maturation by identifying and integrating the human studies on this topic. We found 89 human studies in the literature that identified 24 LH follicle/oocyte signaling proteins. These studies show that human oocyte meiotic maturation is regulated by the same proteins that regulate animal oocyte meiotic maturation. We also found that these LH signaling pathway molecules regulate human oocyte quality and subsequent embryo quality. Remarkably, in vitro maturation (IVM) prematuration culture (PMC) protocols that manipulate the LH signaling pathway improve human oocyte quality of cultured human oocytes. This knowledge has improved clinical human IVM efficiency which may become a routine alternative ART for some infertile patients.

Analysis of NR5A1 in 142 patients with premature ovarian insufficiency, diminished ovarian reserve, or unexplained infertility

Ovarian deficiency, including diminished ovarian reserve and premature ovarian insufficiency, represents one of the main causes of female infertility. Little is known of the genetic basis of diminished ovarian reserve, while premature ovarian insufficiency often has a genetic basis, with genes affecting various processes. NR5A1 is a key gene required for gonadal function, and variants are associated with a wide phenotypic spectrum of disorders of sexual development, and are found in 0.26-8% of patients with premature ovarian insufficiency. As there is some debate about the extent of involvement of NR5A1 in the pathogenesis of ovarian deficiency, we performed an in-depth analysis of NR5A1 variants detected in a cohort of 142 patients with premature ovarian insufficiency, diminished ovarian reserve, or unexplained infertility associated with normal ovarian function. We identified rare non-synonymous protein-altering variants in 2.8 % of women with ovarian deficiency and no such variants in our small cohort of women with infertility but normal ovarian function. We observed previously reported variants associated with premature ovarian insufficiency in patients with diminished ovarian reserve, highlighting a genetic relationship between these conditions. We confirmed functional impairment resulting from a p.Val15Met variant, detected for the first time in a patient with premature ovarian insufficiency. The remaining variants were associated with preserved transcriptional activity and localization of NR5A1, indicating that rare NR5A1 variants may be incorrectly curated if functional studies are not undertaken, and/or that NR5A1 variants may have only a subtle impact on protein function and/or confer risk of ovarian deficiency via oligogenic inheritance.

Electroacupuncture Enhances Number of Mature Oocytes and Fertility Rates for In Vitro Fertilization

Objective: The increasing prevalence of infertility every year is in line with the increasing need for in vitro fertilization (IVF) programs. Failure of oocyte maturation is an obstacle that often causes low success in IVF. According to several studies, controlled ovarian stimulation (COS) has been reported to increase the risk of granulosa-cell apoptosis associated with inhibition of oocyte maturation. This study was conducted to determine the effect of electroacupuncture (EA) on oocyte maturation; rate of fertilization; granulosa-cell apoptosis; and levels of growth-differentiation factor 9 (GDF9) and bone-morphogenetic protein 15 (BMP15) an IVF program. Materials and Methods: A randomized controlled trial was conducted with 24 subjects who were in the IVF program. Subjects were randomly allocated into verum-EA (n = 12) and sham-EA groups (n = 12). Microscopic assessment of oocyte maturation and rate of fertilization was performed by embryologists, and examinations of granulosa-cell apoptosis index (Bax/Bcl-2 ratio), GDF9, and BMP15 were performed, using real-time quantitative polymerase chain reaction and messenger-RNA techniques. Results: There were significant differences in oocyte maturation (P = 0.02) and fertilization rates (P = 0.03) between the verum-EA and sham-EA groups. There were differences in granulosa-cell apoptosis index between the verum-EA and sham-EA groups (P < 0.001). There were significant differences in Bax-protein expression (P = 0.04) and Bcl-2 (P = 0.03) granulosa cells between the verum-EA and sham-EA groups. There was no significant difference in GDF9 levels (P = 0.34) and BMP15 (p = 0.47) between the verum-EA and sham-EA groups. Conclusions: EA can enhance oocyte maturation and fertilization rate, and reduce the granulosa-cell apoptosis index in an IVF program.

The role of BMP15 and GDF9 in the pathogenesis of primary ovarian insufficiency

Endocrine and paracrine signals can be key regulators of ovarian physiology. The oocyte secretes growth factors which directly induce follicular development by a complex paracrine signalling process, and the transforming growth factorβ (TGF-β) superfamily has a pivotal role in this process. The bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) genes are relevant members of the TGF-β superfamily that encode proteins secreted by the oocytes into the ovarian follicles, where they contribute to creating an environment supporting follicle selection and growth. Their main functions include regulating cellular proliferation/differentiation, follicular survival/atresia, and oocyte maturation. Recent functional studies have validated genetic factors (Progesterone receptor membrane component 1 (PGRMC1)), Fragile X mental retardation 1 (FMR1, GDF9 and BMP15) as being causative of primary ovarian insufficiency (POI), BMP15/GDF9 gene variants were found to have a high incidence on the POI phenotype. This review considers the most recent research regarding the role of BMP15 and GDF9 in the genetic control of follicular development, paying special attention to the pathogenesis of POI.

Oocyte-Secreted Factors Synergize With FSH to Promote Aromatase Expression in Primary Human Cumulus Cells

CONTEXT

The role of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) on aromatase regulation is poorly understood in humans.

OBJECTIVE

Determine GDF9 and BMP15 effects on FSH stimulation of estradiol production in primary human cumulus granulosa cells (GCs). We hypothesized that the combination of GDF9 and BMP15 potentiates FSH-induced aromatase expression.

DESIGN

Primary human cumulus GCs in culture.

SETTING

University infertility center.

PATIENTS OR OTHER PARTICIPANTS

GCs of 60 women undergoing in vitro fertilization were collected.

INTERVENTIONS

Cells were treated with GDF9 and/or BMP15 (GB) in the presence or absence of FSH, dibutyryl cAMP, or SMAD inhibitors.

MAIN OUTCOME MEASURES

Promoter activity, mRNA, protein, and estradiol levels were quantified.

RESULTS

FSH and GB treatment increased CYP19A1 promoter activity, mRNA, and protein levels as well as estradiol when compared with cells treated with FSH only. GB treatment potentiated cAMP stimulation of aromatase and IGF2 stimulation by FSH. GB effects were inhibited by SMAD3 inhibitors and IGF1 receptor inhibitors. GB, but not FSH, stimulates SMAD3 phosphorylation.

CONCLUSION

The combination of GDF9 and BMP15 potently stimulates the effect of FSH and cAMP on CYP19a1 promoter activity and mRNA/protein levels. These effects translate into an increase in estradiol production. This potentiation seems to occur through activation of the SMAD2/3 and SMAD3 signaling pathway and involves, at least in part, the effect of the IGF system.

Fetal Growth Restriction Is Associated With Decreased Number of Ovarian Follicles and Impaired Follicle Growth in Young Adult Guinea Pig Offspring

BACKGROUND

The mechanisms mediating the impacts of fetal growth restriction (FGR) on follicular development are commonly studied in mouse/rat models, where ovarian development occurs largely during the early postnatal period. These models have shown that FGR is associated with premature follicle loss, early pubertal onset, and accelerated ovarian aging. Whether the same occurs in precocious species is unknown.

OBJECTIVE

Since guinea pig follicle development occurs in utero in a manner consistent with human ovarian development, we sought to determine whether FGR had similar impacts on guinea pig ovarian development.

METHODS

Dunkin-Hartley guinea pig dams were randomized to receive a control (CON) or a nutrient-restricted diet (FGR) prior to conception until weaning. Offspring ovaries were collected at prepubertal (postnatal day [P] 25) and young adult (P110) time points.

RESULTS

Prepubertal offspring exposed to FGR showed little differences in ovarian transcript levels and follicle counts. Young adult FGR offspring, however, showed reductions in the number of transitioning, primary, and antral follicles, as well as corpora lutea. This loss in follicles was associated with reduced insulin-like growth factor receptor and growth differentiation factor-9 messenger RNA levels in FGR P110 offspring compared to CON.

CONCLUSION

We demonstrate that FGR in guinea pigs is accompanied by perturbations in signaling pathways essential for proper follicle growth and manifests as reductions in growing follicles in offspring, but these changes do not manifest until postpuberty. These data support the fact that accelerated reproductive maturation/aging is a conserved phenotype that is associated with in utero nutritional adversity.

Transcriptional landscape of mouse-aged ovaries reveals a unique set of non-coding RNAs associated with physiological and environmental ovarian dysfunctions

The progressive and physiological decline in ovarian function depends on the rate of follicular loss by atresia, contributing to the reduction in ovarian reserve. Genetics and environmental factors play important roles in ovarian senescence and in the onset of ovarian dysfunctions such as diminished ovarian reserve. A better understanding of the mechanisms underlying ovarian aging and their regulation by genetic and environmental factors is needed to evaluate ovarian reserve and to predict fertility potential by identification of more accurate and less invasive markers. We report transcriptomic data (i) implicating novel (e.g. EIF2 signalling) and well-known pathways (e.g. TGFβ signalling), and (ii) defining a unique set of non-coding RNA (ncRNA), both associated with ovarian function. The latter includes miRNAs (e.g. Mir143 and Mir145), snoRNAs (e.g. Snord16a and Snora34), and one lncRNA (Gas5), which are differentially expressed in middle-aged ovaries (12 months) vs young-aged (3 months) from CD1 mice. Experimental analysis confirms that ovary lifespan varies across genetic backgrounds in mice and, genetics influences the response to environmental perturbations such as diet. Moreover, the identified ncRNAs were verified in a model of reproductive dysfunction promoted by the environmental toxicant ethylenthiourea. We also report the increase of miRNA143 and miRNA145 in follicular fluid of women with diminished ovarian reserve. Their levels inversely correlate with the hormonal profile and with the number of the oocytes recruited upon hormonal stimulation. Overall, we report a transcriptomic signature for ovarian dysfunction in vivo that provides a valuable resource for translational research in human reproductive aging.

Connecting links between genetic factors defining ovarian reserve and recurrent miscarriages

PURPOSE

Approximately 1-2% of the women faces three or more successive spontaneous miscarriages termed as recurrent miscarriage (RM). Many clinical factors have been attributed so far to be the potential risk factors in RM, including uterine anomalies, antiphospholipid syndrome, endocrinological abnormalities, chromosomal abnormalities, and infections. However, in spite of extensive studies, reviews, and array of causes known to be associated with RM, about 50% cases encountered by treating physicians remains unknown. The aims of this study were to evaluate recent publications and to explore oocyte-specific genetic factors that may have role in incidence of recurrent miscarriages.

METHOD

Recent studies have identified common molecular factors contributing both in establishment of ovarian reserve and in early embryonic development. Also, studies have pointed out the relationship between the age-associated depletion of OR and increase in the risk of miscarriages, thus suggestive of an interacting biology. Here, we have gathered literature evidences in establishing connecting links between genetic factors associated with age induced or pathological OR depletion and idiopathic RM, which are the two extreme ends of female reproductive pathology.

CONCLUSION

In light of connecting etiological link between infertility and RM as reviewed in this study, interrogating the oocyte-specific genes with suspected roles in reproductive biology, in cases of unexplained RM, may open new possibilities in widening our understanding of RM pathophysiology.

Pharmacogenomics in IVF: A New Era in the Concept of Personalized Medicine

Pharmacogenomics is a promising approach in the field of individualized medicine in in vitro fertilization (IVF) treatment that aims to develop optimized pharmacotherapy depending on the genetic background of each infertile woman, thus to ensure maximum effectiveness of the medication used, with minimal side effects. The unique genetic information of each infertile woman, in combination with already known, as well as new predictors of ovarian response and the progress of pharmacoepigenomics, is anticipated to greatly benefit the process of controlled ovarian stimulation. This review analyses current data on IVF pharmacogenomics, a new approach that is gradually moving to the frontline of modern IVF treatment.

Molecular Aspects and Clinical Relevance of GDF9 and BMP15 in Ovarian Function

Growth and differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are oocyte-secreted factors with a leading role in the control of ovarian function in female reproduction, modulating both the cell fate of the somatic granulosa cells and the quality and developmental competence of the egg. This short review aims to consolidate the molecular aspects of GDF9 and BMP15 and their integral actions in female fertility to understand particularly their effects on oocyte quality and fetal growth. The significant consequences of mutations in the GDF9 and BMP15 genes in women with dizygotic twins as well as the clinical relevance of these oocyte factors in the pathogenesis of primary ovarian insufficiency and polycystic ovary syndrome are also addressed.

Repertoire of bone morphogenetic proteins and growth/differentiation factors in ovary of the Indian wall lizard (Hemidactylus flaviviridis) with emphasis on differential expression and gonadotropic regulation of bmp15 and gdf9

Analysis of ovarian transcriptome of Indian wall lizard demonstrates the existence of several bone morphogenetic proteins (bmp1, 2, 3, 3b, 7, 8, 15) and growth/differentiation factors (gdf5, 9) for the first time in reptilian ovary. The characterization of putative full-length/partial protein sequences of BMPs (BMP2, 3, 3b, 7, 15) and GDF9 showed high homology of their TGF-β domain with that of other vertebrates while BMP1 bore homology to zinc-dependent metalloprotease. Phylogenetic analyses showed clustering of BMPs and GDF9 from wall lizards with that of squamates lying in close proximity to chelonia, crocodilia and aves. This study also correlates the expression of ovarian bmp15 and gdf9 with folliculogenesis. Level of bmp15 dramatically increased with the onset of follicular growth in early recrudescence and attained peak during late recrudescence whereas gdf9 sharply decreased during recrudescence as compared to regression. Nonetheless, expression of these growth factors decreased appreciably with the formation of vitellogenic follicle during breeding phase. Ovarian expression of bmp15 and gdf9 appeared to be regulated by gonadotropin as bmp15 considerably increased while gdf9 decreased in parallel to follicular development after administration of 3 injections of FSH. Expression of both the growth factors declined with the prolongation of treatment that led to formation of early/late vitellogenic follicle. Our in vitro study revealed stimulatory effect of FSH on expression of bmp15 and gdf9 in early growing, previtellogenic and early vitellogenic follicles. In light of in vitro results, FSH-induced in vivo decline in gene expression seems to be due to some other FSH-induced factor.

The effect of dehydroepiandrosterone supplementation on ovarian response is associated with androgen receptor in diminished ovarian reserve women

Background

Diminished ovarian reserve(DOR) is associated with female infertility and poor response to ovarian stimulation. Our objective was to assess the effect of dehydroepiandrosterone(DHEA) on DOR women and to explore whether the improvement of ovarian response after DHEA supplementation was dependent on the expression levels of androgen receptor(AR).

Methods

A prospective cohort study was performed in the Department of Human Reproductive Medicine, Beijing Obstetrics and Gynecology Hospital during August 2014 to August 2016. 103 DOR women who completed the study were divided into the DHEA group (n = 53), which received DHEA supplementation (25 mg three times a day) for 8 weeks, and the control group (n = 50), which did not receive DHEA, before the IVF cycles. Serum hormone levels(FSH, LH, E₂, T, DHEAs, AMH, INHB), antral follicle count(AFC) and the expression of AR and FSH receptor(FSHR) in granulosa cells(GCs) were measured, meanwhile ovarian response parameters and IVF outcomes were compared. The GCs from another 36 DOR women were cultured with different concentrations of DHEA in vitro. Then, we compared the expression of AR and FSHR in GCs according to the different numbers of oocytes retrieved both in DHEA and control group.

Results

In the present study, DHEA supplementation resulted in significantly higher levels of serum T(P = 0.047), DHEAs(P = 0.019) and AR mRNA expression in GCs(P = 0.049). In vitro experiment, the protein and mRNA expression of AR and FSHR in the preovulatory GCs were significantly increased in response to DHEA supplementation(P <0.05). No significant differences were found in ovarian reserve, ovarian response, or IVF outcomes between the two groups. Subgroup analyses showed the levels of AR and FSHR mRNA in GCs were significantly increased in DHEA group with ≥5 oocytes retrieved(P <0.05).

Conclusion

DHEA supplementation can increase the expression of AR in preovulatory GCs both in vivo and in vitro. The selective beneficial effects of DHEA supplementation on ovarian response in DOR women may depend on the increasing expression of AR and FSHR in GCs.

Trial registration

The Chinese Clinical Trial Registry (ChiCTR-IPR-15006126). Retrospectively Registered 19 March 2015.

Oocyte-somatic cell interactions in the human ovary-novel role of bone morphogenetic proteins and growth differentiation factors

BACKGROUND

Initially identified for their capability to induce heterotopic bone formation, bone morphogenetic proteins (BMPs) are multifunctional growth factors that belong to the transforming growth factor β superfamily. Using cellular and molecular genetic approaches, recent studies have implicated intra-ovarian BMPs as potent regulators of ovarian follicular function. The bi-directional communication of oocytes and the surrounding somatic cells is mandatory for normal follicle development and oocyte maturation. This review summarizes the current knowledge on the physiological role and molecular determinants of these ovarian regulatory factors within the human germline-somatic regulatory loop.

OBJECTIVE AND RATIONALE

The regulation of ovarian function remains poorly characterized in humans because, while the fundamental process of follicular development and oocyte maturation is highly similar across species, most information on the regulation of ovarian function is obtained from studies using rodent models. Thus, this review focuses on the studies that used human biological materials to gain knowledge about human ovarian biology and disorders and to develop strategies for preventing, diagnosing and treating these abnormalities.

SEARCH METHODS

Relevant English-language publications describing the roles of BMPs or growth differentiation factors (GDFs) in human ovarian biology and phenotypes were comprehensively searched using PubMed and the Google Scholar database. The publications included those published since the initial identification of BMPs in the mammalian ovary in 1999 through July 2016.

OUTCOMES

Studies using human biological materials have revealed the expression of BMPs, GDFs and their putative receptors as well as their molecular signaling in the fundamental cells (oocyte, cumulus/granulosa cells (GCs) and theca/stroma cells) of the ovarian follicles throughout follicle development. With the availability of recombinant human BMPs/GDFs and the development of immortalized human cell lines, functional studies have demonstrated the physiological role of intra-ovarian BMPs/GDFs in all aspects of ovarian functions, from follicle development to steroidogenesis, cell–cell communication, oocyte maturation, ovulation and luteal function. Furthermore, there is crosstalk between these potent ovarian regulators and the endocrine signaling system. Dysregulation or naturally occurring mutations within the BMP system may lead to several female reproductive diseases. The latest development of recombinant BMPs, synthetic BMP inhibitors, gene therapy and tools for BMP-ligand sequestration has made the BMP pathway a potential therapeutic target in certain human fertility disorders; however, further clinical trials are needed. Recent studies have indicated that GDF8 is an intra-ovarian factor that may play a novel role in regulating ovarian functions in the human ovary.

WIDER IMPLICATIONS

Intra-ovarian BMPs/GDFs are critical regulators of folliculogenesis and human ovarian functions. Any dysregulation or variations in these ligands or their receptors may affect the related intracellular signaling and influence ovarian functions, which accounts for several reproductive pathologies and infertility. Understanding the normal and pathological roles of intra-ovarian BMPs/GDFs, especially as related to GC functions and follicular fluid levels, will inform innovative approaches to fertility regulation and improve the diagnosis and treatment of ovarian disorders.

Identification of the key regulating genes of diminished ovarian reserve (DOR) by network and gene ontology analysis

Diminished ovarian reserve (DOR) is one of the reasons for infertility that not only affects both older and young women. Ovarian reserve assessment can be used as a new prognostic tool for infertility treatment decision making. Here, up- and down-regulated gene expression profiles of granulosa cells were analysed to generate a putative interaction map of the involved genes. In addition, gene ontology (GO) analysis was used to get insight intol the biological processes and molecular functions of involved proteins in DOR. Eleven up-regulated genes and nine down-regulated genes were identified and assessed by constructing interaction networks based on their biological processes. PTGS2, CTGF, LHCGR, CITED, SOCS2, STAR and FSTL3 were the key nodes in the up-regulated networks, while the IGF2, AMH, GREM, and FOXC1 proteins were key in the down-regulated networks. MIRN101-1, MIRN153-1 and MIRN194-1 inhibited the expression of SOCS2, while CSH1 and BMP2 positively regulated IGF1 and IGF2. Ossification, ovarian follicle development, vasculogenesis, sequence-specific DNA binding transcription factor activity, and golgi apparatus are the major differential groups between up-regulated and down-regulated genes in DOR. Meta-analysis of publicly available transcriptomic data highlighted the high coexpression of CTGF, connective tissue growth factor, with the other key regulators of DOR. CTGF is involved in organ senescence and focal adhesion pathway according to GO analysis. These findings provide a comprehensive system biology based insight into the aetiology of DOR through network and gene ontology analyses.

Modifications of human growth differentiation factor 9 to improve the generation of embryos from low competence oocytes

Growth differentiation factor 9 (GDF9) is an oocyte-derived growth factor that plays a critical role in ovarian folliculogenesis and oocyte developmental competence and belongs to the TGF-β family of proteins. Recombinant human GDF9 (hGDF9) is secreted in a latent form, which in the case of the fully processed protein, has the proregion noncovalently associated with the mature region. In this study, we investigated a number of amino acid residues in the mature region of hGDF9 that are different from the corresponding residues in the mouse protein, which is not latent. We designed, expressed, and purified 4 forms of chimeric hGDF9 (M1-M4) that we found to be active in a granulosa cell bioassay. Using a porcine in vitro maturation model with inherent low developmental competence (yielding 10%-20% blastocysts), we tested the ability of the chimeric hGDF9 proteins to improve oocyte maturation and developmental competence. Interestingly, one of the chimeric proteins, M3, was able to significantly increase the level of embryo production using such low competence oocytes. Our molecular modeling studies suggest that in the case of hGDF9 the Gly(391)Arg mutation probably increases receptor binding affinity, thereby creating an active protein for granulosa cells in vitro. However, for an improvement in oocyte developmental competence, a second mutation (Ser(412)Pro), which potentially decreases the affinity of the mature region for the proregion, is also required.

Implications of Blood Type for Ovarian Reserve and Infertility - Impact on Oocyte Yield in IVF Patients

Introduction: Diminished ovarian reserve (DOR) has been linked to certain subpopulations and distinct gene polymorphisms. It has even been hypothesized that the AB0 blood group system could be linked to ovarian reserve (OR) as reflected by early follicular phase follicle stimulating hormone (FSH) levels. Although estimation of OR is routinely done using levels of anti-Müllerian hormone (AMH), FSH, estradiol or inhibin B, the diagnostic accuracy of these markers is often limited. The aim of this study was to evaluate whether there is any correlation between IVF patients' AB0 blood group system and ART outcome. Methods: In this retrospective observational single-center study we investigated the outcome of 1889 IVF cycles carried out between 2005 and 2012 with regard to blood type and OR in different age groups (21-36 years and 37-43 years). The number of cumulus oocyte complexes (COCs) and metaphase II oocytes obtained after ovarian stimulation, fertilization rate (FR), pregnancy rate (PR) and birth rate (BR) were evaluated with respect to maternal age (21-36 and 37-43 years, respectively). Results: We found no significant differences in the average number of COCs after ovum pick-up in either of the age groups. Moreover, the mean number of MII oocytes and 2PN stages were similar for all blood type groups. As regards IVF outcome measured in terms of PR and BR, no significant differences were observed between the different blood groups. In conclusion, no correlation was found between blood type and female fertility. Discussion: The most precise definition of OR is determining the number of competent oocytes. Based on the finding of our study, the hypothesis that there is a correlation between OR and AB0 blood group system can be dismissed for Caucasian IVF patients.

Is there any relationship between cardiovascular risk markers and young women with diminished ovarian reserve?

OBJECTIVE

It has been widely known that cardiovascular disease (CVD) risk is increased in menopause. The aim of the study was to evaluate whether this risk was elevated in young women with diminished ovarian reserve (DOR).

METHODS

A hundred women with DOR and 100 women with normal ovarian reserve (NOR) attending the infertility unit at Suleymaniye Maternity, Research &Training Hospital, were enrolled in the study. CVD risk markers such as insulin resistance (defined by the homeostasis model assessment ratio [HOMA-IR]), C-reactive protein (CRP), low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), and triglyceride (TG) were assessed.

RESULTS

HOMA-IR, CRP, TG, LDL levels were higher and HDL was lower among patients with DOR compared to the controls (p < 0.05 for all). There were positive associations between DOR and HOMA-IR, CRP, TG, LDL levels and a negative correlation with HDL (p < 0.05 for all). However, multivariate logistic regression analysis showed that HOMA-IR, CRP, TG, and HDL were independent variables that were associated with DOR.

CONCLUSIONS

CVD risk markers were increased in women with DOR. Further studies with larger groups are needed to investigate the nature of the link in these patients.

Ovarian aging and premature ovarian failure

Physiological reproductive aging occurs as a result of a decrease in the number and quality of oocytes in ovarian cortex follicles. Although the reason for the decrease in the quality of the pool and follicular oocytes is not fully understood, endocrine, paracrine, genetic, and metabolic factors are thought to be effective. Nowadays, in order to understand the mechanisms of ovarian aging, genomic research has gained importance. The effect of co-factors, such as telomerase and ceramide, in the ovarian aging process is only getting ascertained with new research studies. The most important tests in the assessment of ovarian aging are antral follicle count and anti-Mullerian hormone.

Bone morphogenetic protein 15 in the pro-mature complex form enhances bovine oocyte developmental competence

Developmental competence of in vitro matured (IVM) oocytes needs to be improved and this can potentially be achieved by adding recombinant bone morphogenetic protein 15 (BMP15) or growth differentiation factor (GDF9) to IVM. The aim of this study was to determine the effect of a purified pro-mature complex form of recombinant human BMP15 versus the commercially available bioactive forms of BMP15 and GDF9 (both isolated mature regions) during IVM on bovine embryo development and metabolic activity. Bovine cumulus oocyte complexes (COCs) were matured in vitro in control medium or treated with 100 ng/ml pro-mature BMP15, mature BMP15 or mature GDF9 +/− FSH. Metabolic measures of glucose uptake and lactate production from COCs and autofluorescence of NAD(P)H, FAD and GSH were measured in oocytes after IVM. Following in vitro fertilisation and embryo culture, day 8 blastocysts were stained for cell numbers. COCs matured in medium +/− FSH containing pro-mature BMP15 displayed significantly improved blastocyst development (57.7±3.9%, 43.5±4.2%) compared to controls (43.3±2.4%, 28.9±3.7%) and to mature GDF9+FSH (36.1±3.0%). The mature form of BMP15 produced intermediate levels of blastocyst development; not significantly different to control or pro-mature BMP15 levels. Pro-mature BMP15 increased intra-oocyte NAD(P)H, and reduced glutathione (GSH) levels were increased by both forms of BMP15 in the absence of FSH. Exogenous BMP15 in its pro-mature form during IVM provides a functional source of oocyte-secreted factors to improve bovine blastocyst development. This form of BMP15 may prove useful for improving cattle and human artificial reproductive technologies.

The fundamental role of bone morphogenetic protein 15 in ovarian function and its involvement in female fertility disorders

BACKGROUND

A large number of studies have contributed to understanding the general mechanisms driving ovarian folliculogenesis in humans and show a complex endocrine dialog between the central nervous system, the pituitary and the ovary, integrated by various intraovarian paracrine messages. The role of intraovarian paracrine regulation has acquired more relevance in the recent years owing to the discovery of previously unknown factors, such as the oocyte-derived bone morphogenetic protein (BMP)15.

METHODS

A thorough literature search was carried out in order to summarize what has been reported so far on the role of BMP15, and the BMP15 paralog, growth and differentiation factor 9 (GDF9), in ovarian function and female fertility. Research articles published in English until March 2014 were included.

RESULTS

The biological actions of BMP15 include: (i) the promotion of follicle growth and maturation starting from the primary gonadotrophin-independent phases of folliculogenesis; (ii) the regulation of follicular granulosa cell (GC) sensitivity to FSH action and the determination of ovulation quota; (iii) the prevention of GC apoptosis and (iv) the promotion of oocyte developmental competence. The existence of biologically active heterodimers with GDF9, and/or the synergistic co-operation of BMP15 and GDF9 homodimers are indeed relevant in this context. Experimental disruption of the bmp15 gene in mice resulted in a mild fertility defect limited to females, whereas natural missense mutations in ewes cause variable phenotypes (ranging from hyperprolificacy to complete sterility) depending on a fine gene dosage mechanism also involving GDF9. Strong evidence supports the concept that such a mechanism plays an important role in the regulation of ovulation rate across mammalian and non-mammalian species. Following the discovery of sheep fecundity genes, several research groups have focused on alterations in human BMP15 associated with primary ovarian insufficiency (POI) or polycystic ovary syndrome. Several variants of BMP15 are significantly associated with POI supporting their pathogenic role, but the underlying biological mechanism is still under investigation and of great interest in medicine. BMP15 maps to the Xp locus involved in the determination of the ovarian defect in Turner syndrome and significantly contributes to the determination of ovarian reserve. Pioneering studies in women undergoing controlled ovarian stimulation indicate that BMP15 may represent a marker of ovarian response or oocyte quality.

CONCLUSIONS

BMP15, an oocyte-derived growth and differentiation factor, is a critical regulator of folliculogenesis and GC activities. Variations in BMP15 gene dosage have a relevant influence on ovarian function and can account for several defects of female fertility. The modulation of BMP15 action may have interesting pharmacological perspectives and the analysis of BMP15 may become a useful marker in IVF procedures. Recent outcomes indicate that the close interactions of BMP15/GDF9 have a critical biological impact that should be taken into account in future studies.

Genetic associations with diminished ovarian reserve: a systematic review of the literature

PURPOSE

Diminished ovarian reserve (DOR) affects 10 % of women seeking fertility treatment. Although it is much more prevalent than premature ovarian failure, less is known about its etiology. The purpose of this article is to review the possible genetic causes of, and associations with, pathologic DOR.

METHODS

A systematic review was conducted using PubMed from 1966 through November 2013.

RESULTS

Twenty-one articles identified genes associated with DOR: one gene mutation (FMR1), three polymorphisms (GDF9, FSHR, and ESR1), and seven genes differentially expressed between women with DOR and controls (AMH, LHCGR, IGF1, IGF2, IGF1R, IGF2R and GREM1). Six candidate genes were discovered in mice, including Foxl2, Gdf9, Bmp15, Aire, Wnt4, and Gpr3. Two case reports of chromosomal translocations were also identified.

CONCLUSIONS

While the etiology of pathologic DOR is likely multifactorial, it is possible that many cases attributed to an idiopathic cause may have a genetic component. Larger studies are needed to expose the impact gene mutations, polymorphisms, and epigenetics have on pathologic DOR.

Effects of differing oocyte-secreted factors during mouse in vitro maturation on subsequent embryo and fetal development

PURPOSE

We hypothesised that varying native oocyte-secreted factor (OSF) exposure or using different recombinant OSF peptides would have differential effects on post-in vitro maturation (IVM) embryo and fetal development.

METHODS

Mouse cumulus oocyte complexes (COCs) were treated with the purified mature domain of GDF9 and/or BMP15 or were co-cultured with denuded oocytes (DOs) from 0 h or 3 h of IVM. DOs were matured for 3 h as either intact COCs+/-FSH before denuding, or as DOs + FSH. COCs were fertilised and blastocyst development was assessed on days 5 and 6, and either differentially stained for ICM numbers or vitrified/warmed embryos were transferred to recipients to assess implantation and fetal rates.

RESULTS

No improvement in embryo development was observed with the addition of GDF9 and/or BMP15 to IVM. In contrast, embryos derived from COCs co-cultured with DOs had significantly improved blastocyst rates and ICM numbers compared to controls (P < 0.05). The highest response was obtained when DOs were first added to COCs at 3 h of IVM, after being pre-treated (0-3 h) as COCs + FSH. Compared to control, co-culture with DOs from 3 h did not affect implantation rates but more than doubled fetal yield (21% vs 48%; P < 0.05). GDF9 Western blot analysis was unable to detect any differences in quantity or form of GDF9 (17 and 65 kDa) in extracts of DO at 0 h or 3 h.

CONCLUSIONS

This study provides new knowledge on means to improve oocyte quality in vitro which has the potential to significantly aid human infertility treatment and animal embryo production technologies.