Cumulus and granulosa cell markers of oocyte and embryo quality

DNA methylation, but not microRNA expression, is affected by in vitro THC exposure in bovine granulosa cells

BACKGROUND

A global increase in cannabis use has led to questions about its effects on fertility. The rise in consumption amongst women of reproductive age is a growing concern, as this group is vulnerable in terms of reproductive health. Ample evidence suggests that the psychoactive component of cannabis, Δ9-Tetrahydrocannabinol (THC), interacts with the endocannabinoid system (ECS), that helps regulate mammalian reproduction. This study aimed to research the epigenetic effects of THC in bovine granulosa cells (GCs) by (1) investigating global DNA methylation via measuring 5-mC and 5-hmC levels; (2) measuring key methylation regulators, including the methylating enzymes DNMT1, DNMT3a, DNMT3b and the demethylases TDG and TET1/2/3; and (3) assessing fertility-associated miRNAs key in developmental competency, including miR-21, -155, -33b, -324 and -346.

METHODS

Bovine GCs were used as a translational model for reproductive toxicity in humans. To determine THC effects, GCs were isolated from Cumulus-Oocyte-Complexes (COCs) from bovine ovaries, cultured in vitro for 7 days, or until confluent, and cryopreserved at passage 1 (P1). For experimentation, cells were thawed, cultured until passage 2 (P2), serum restricted for 24-h and treated for 24-h in one of five groups: control, vehicle (1:1:18 ethanol: tween: saline) and three clinically relevant THC doses (0.032, 0.32 and 3.2 μM). Global methylation was assessed by measuring 5-mC and 5-hmC levels with flow cytometry. To assess mRNA and protein expression of methylation regulators and miRNA profiles, qPCR and Western Blotting were utilized. Shapiro-Wilk test was used to determine normality within datasets. One-way ANOVA was applied to determine statistical significance using GraphPad Prism 6.0.0.

RESULTS

Results indicate a significant decrease (p = 0.0435) in 5-mC levels following low THC exposure, while no changes were observed in 5-hmC levels. A significant increase in DNMT1 following high THC exposure at the RNA level (p < 0.05) and a significant increase following low THC exposure at the protein level (p = 0.0048) were also observed. No significant differences were observed in DNMT3a/3b, TDG, TET1/2/3 mRNAs or in any of the miRNAs analyzed.

CONCLUSIONS

This research suggests that THC mainly affects DNA methylation, but not miRNA profiles, ultimately altering gene expression and likely impairing oocyte competence, maturation, and fertilization potential.

Exploring the effect of Gouqi Nuzhen Liuhe decoction on the PI3K/mTOR signaling pathway for premature ovarian insufficiency based on system pharmacology

Objective

To explore the effect of Gouqi Nuzhen Liuhe Decoction (GNLHD) on the PI3K/mTOR Signaling Pathway for Premature Ovarian Insufficiency (POI) based on system pharmacology.

Methods

First, the system pharmacology approach was used to predict the mechanism of GNLHD. Then, mice were randomly divided into model group, positive group, GNLHD high-dose group, GNLHD medium-dose group, and GNLHD low-dose group. Hematoxylin-eosin (HE) staining was used to observe the pathological changes of ovarian tissue under light microscope. The expression levels of estradiol (E2), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were detected by enzyme-linked immunosorbent assay. The expressions of PI3K, AKT1 and mTOR proteins in ovarian tissue were detected by immunohistochemistry.

Results

The results of system pharmacology showed that GNLHD may regulate biological processes and signaling pathways such as: reproductive structure development, reproductive system development, Oocyte meiosis and so on. Compared with the model group, the levels of E2 in the GNLHD group were increased, and the levels of FSH and LH were decreased (P < 0.05). Compared with the model group, the number of mature follicles in the GNLHD group was significantly increased, the number of atretic follicles was relatively decreased, and the expressions of PI3K, AKT1, and MTOR proteins in the GNLHD group were significantly increased (P < 0.05).

Conclusion

GNLHD may improve the ovarian function of POI mice by affecting the expression of PI3K, AKT1 and mTOR proteins, promote the growth and development of follicles, increase the E2 level, reduce FSH and LH level, and maintain the stability of the ovarian internal environment.

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.

Metabolic imaging of human cumulus cells reveals associations with pregnancy and live birth

STUDY QUESTION

Can fluorescence lifetime imaging microscopy (FLIM) detect associations between the metabolic state of cumulus cell (CC) samples and the clinical outcome of the corresponding embryos?

SUMMARY ANSWER

FLIM can detect significant variations in the metabolism of CC associated with the corresponding embryos that resulted in a clinical pregnancy versus those that did not.

WHAT IS KNOWN ALREADY

CC and oocyte metabolic cooperativity are known to be necessary for the acquisition of developmental competence. However, reliable CC biomarkers that reflect oocyte viability and embryo developmental competency have yet to be established. Quantitative measures of CC metabolism could be used to aid in the evaluation of oocyte and embryo quality in ART.

STUDY DESIGN, SIZE, DURATION

A prospective observational study was carried out. In total, 223 patients undergoing IVF with either conventional insemination or ICSI at a tertiary care center from February 2018 to May 2020 were included, with no exclusion criteria applied.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This cohort had a mean maternal age of 36.5 ± 4.4 years and an average oocyte yield of 16.9 (range 1-50). One to four CC clusters from each patient were collected after oocyte retrieval and vitrified. CC metabolic state was assessed using FLIM to measure the autofluorescence of the molecules NAD(P)H and FAD+, which are essential for multiple metabolic pathways. CC clusters were tracked with their corresponding oocytes and associated embryos. Patient age, Day 3 and Day 5/6 embryo morphological grades, and clinical outcomes of embryos with traceable fate were recorded. Nine FLIM quantitative parameters were obtained for each CC cluster. We investigated associations between the FLIM parameters and patient maternal age, embryo morphological rank, ploidy, and clinical outcome, where false discovery rate P-values of <0.05 were considered statistically significant.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 851 CC clusters from 851 cumulus-oocyte complexes from 223 patients were collected. Of these CC clusters, 623 were imaged using FLIM. None of the measured CC FLIM parameters were correlated with Day 3 morphological rank or ploidy of the corresponding embryos, but FAD+ FLIM parameters were significantly associated with morphological rank of blastocysts. There were significant differences for FAD+ FLIM parameters (FAD+ fraction engaged and short lifetime) from CC clusters linked with embryos resulting in a clinical pregnancy compared with those that did not, as well as for CC clusters associated with embryos that resulted in a live birth compared those that did not.

LIMITATIONS, REASONS FOR CAUTION

Our data are based on a relatively low number of traceable embryos from an older patient population. Additionally, we only assessed CCs from 1 to 4 oocytes from each patient. Future work in a younger patient population with a larger number of traceable embryos, as well as measuring the metabolic state of CCs from all oocytes from each patient, would provide a better understanding of the potential utility of this technology for oocyte/embryo selection.

WIDER IMPLICATIONS OF THE FINDINGS

Metabolic imaging via FLIM is able to detect CC metabolic associations with maternal age and detects variations in the metabolism of CCs associated with oocytes leading to embryos that result in a clinical pregnancy and a live birth versus those that do not. Our findings suggest that FLIM of CCs may be used as a new approach to aid in the assessment of oocyte and embryo developmental competence in clinical ART.

STUDY FUNDING/COMPETING INTEREST(S)

National Institutes of Health grant NIH R01HD092550-03 (to C.R., and D.J.N.). Becker and Hickl GmbH and Boston Electronics sponsored research with the loaning of equipment for FLIM. D.J.N. and C.R. are inventors on patent US20170039415A1.

TRIAL REGISTRATION NUMBER

N/A.

The possible regulatory role of miR-514 and miR-642b in cumulus cells on the oocyte maturation in patients with polycystic ovary syndrome

Polycystic ovary syndrome is a common endocrine disorder in reproductive-age women. Accordingly, abnormal microenvironment may negatively influence oocyte developmental competence as a result of the altered expression profile of cumulus cells (CCs), mainly the key players of oocyte maturation, such as epidermal growth factor receptor (EGFR) and prostaglandin E receptor-2 (PTGER2). This study aimed to examine the expression levels of miR-514, miR-642b, and their candidate target genes (EGFR and PTGER2, respectively) in CCs of immature and mature oocytes in patients with PCOS. A total of 40 oocytes at germinal vesicle (GV) and 40 oocytes at metaphase II (MII) stages were retrieved from 30 PCOS women. Quantitative real-time PCR was performed to analyze the expression level of miR-514, miR-642b, EGFR, and PTGER2 in cumulus cells (CCS) of each oocyte. The expression level of miRNAs and their candidate target genes were compared between CCs of GV and MII oocytes. Our study suggests an inverse relationship exists between the expression levels of miR-514 and EGFR, and miR-642b and PTGER2. Furthermore, we observed that CCs of GV oocytes had higher levels of EGFR and PTGER2 mRNA and lower levels of miR-514 and miR-642b expression compared to those of MII oocytes. The present study demonstrated that miR-514 and miR-642b can regulate oocyte development by targeting EGFR and PTGER2, respectively. Therefore, examination of these miRNAs in CCs could be promising parameters to predict oocyte competence in PCOS patients.

Use of assisted reproductive technologies (ARTs) to shorten the generational interval in ruminants: current status and perspectives

The challenges posed by climate change and increasing world population are stimulating renewed efforts for improving the sustainability of animal production. To meet such challenges, the contribution of genomic selection approaches, in combination with assisted reproductive technologies (ARTs), to spreading and preserving animal genetics is essential. The largest increase in genetic gain can be achieved by shortening the generation interval. This review provides an overview of the current status and progress of advanced ARTs that could be applied to reduce the generation time in both female and male of domestic ruminants. In females, the use of juvenile in vitro embryo transfer (JIVET) enables to generate offspring after the transfer of in vitro produced embryos derived from oocytes of prepubertal genetically superior donors reducing the generational interval and acceleration genetic gain. The current challenge is increasing in vitro embryo production (IVEP) from prepubertal derived oocytes which is still low and variable. The two main factors limiting IVEP success are the intrinsic quality of prepubertal oocytes and the culture systems for in vitro maturation (IVM). In males, advancements in ARTs are providing new strategies to in vitro propagate spermatogonia and differentiate them into mature sperm or even to recapitulate the whole process of spermatogenesis from embryonic stem cells. Moreover, the successful use of immature cells, such as round spermatids, for intracytoplasmic injection (ROSI) and IVEP could allow to complete the entire process in few months. However, these approaches have been successfully applied to human and mouse whereas only a few studies have been published in ruminants and results are still controversial. This is also dependent on the efficiency of ROSI that is limited by the current isolation and selection protocols of round spermatids. In conclusion, the current efforts for improving these reproductive methodologies could lead toward a significant reduction of the generational interval in livestock animals that could have a considerable impact on agriculture sustainability.

Electro-Metabolic Coupling of Cumulus-Oocyte Complex

Oocyte-cumulus cell interaction is essential for oocyte maturation and competence. The bidirectional crosstalk network mediated by gap junctions is fundamental for the metabolic cooperation between these cells. As cumulus cells exhibit a more glycolytic phenotype, they can provide metabolic substrates that the oocyte can use to produce ATP via oxidative phosphorylation. The impairment of mitochondrial activity plays a crucial role in ovarian aging and, thus, in fertility, determining the success or failure of assisted reproductive techniques. This review aims to deepen the knowledge about the electro-metabolic coupling of the cumulus-oocyte complex and to hypothesize a putative role of potassium channel modulators in order to improve fertility, promote intracellular Ca2+ influx, and increase the mitochondrial biogenesis and resulting ATP levels in cumulus cells.

Role of miRNAs in glucose metabolism of mouse cumulus cells†

It is known that the oocyte has a limited capacity to acquire and metabolize glucose, and it must rely on cumulus cells (CCs) to take up glucose and produce pyruvate for use to produce ATP through oxidative phosphorylation. We therefore propose that miRNAs might regulate glucose metabolism (GM) in CCs and might be used as markers for oocyte quality assessment. Here, mouse CC models with impaired glycolysis or pentose phosphate pathway (PPP) were established, and miRNAs targeting the key enzymes in glycolysis/PPP were predicted using the miRNA target prediction databases. Expression of the predicted miRNAs was compared between CCs with normal and impaired glycolysis/PPP to identify candidate miRNAs. Function of the candidate miRNAs was validated by transfecting CCs or cumulus-oocyte-complexes (COCs) with miRNA inhibitors and observing effects on glucose metabolites of CCs and on competence of oocytes. The results validated that miR-23b-3p, let-7b-5p, 34b-5p and 145a-5p inhibited glycolysis, and miR-24-3p, 3078-3p,183-5p and 7001-5p inhibited PPP of CCs. Our observation using a more physiologically relevant model (intact cultured COCs) further validated the four glycolysis-targeting miRNAs we identified. Furthermore, miR-let-7b-5p, 34b-5p and 145a-5p may also inhibit PPP, as they decreased the production of glucose-6-phosphate. In conclusion, miRNAs play critical roles in GM of CCs and may be used as markers for oocyte quality assessment. Summary sentence:  We identified and validated eight new miRNAs that inhibit glycolysis and/or pentose phosphate pathways in cumulus cells (CCs) suggesting that miRNAs play critical roles in glucose metabolism of CCs and may be used for oocyte quality markers.

Indole-3-carbinol ameliorates ovarian damage in female old mice through Nrf2/HO-1 pathway activation

Ovarian aging leads to infertility and birth defects. We aimed to clarify the role of Indole-3-carbinol (I3C) in resistance to oxidative stress, apoptosis, and fibrosis in ovarian aging. I3C was administered via intraperitoneal injection for 3 weeks in young or old mice. Immunohistochemistry; Masson, Sirius red, and TUNEL staining; follicle counting; estrous cycle analysis; and Western blotting were used for validating the protective effect of I3C against ovarian senescence. Human granulosa-like tumor cell line and primary granulosa cells were used for in vitro assay. The results indicated that I3C inhibited ovarian fibrosis and apoptosis while increasing the number of primordial follicles. Mechanistic studies have shown that I3C promoted the nuclear translocation of nuclear factor-erythroid 2-related factor (Nrf2) and upregulated the expression of heme oxygenase 1 (HO-1). Additionally, I3C increased cell viability and decreased lactate dehydrogenase, malondialdehyde, reactive oxygen species and JC-1 levels. Furthermore, the antioxidant effect of I3C was found to be dependent on the activation of Nrf2 and HO-1, as demonstrated by the disappearance of the effect upon inhibition of Nrf2 expression. In conclusion, I3C can alleviate the ovarian damage caused by aging and may be a protective agent to delay ovarian aging.

AKT, p-AKT, ERK1/2 and p-ERK1/2 in Mural Granulosa Cells Are Not Correlated to Different Ovarian Stimulation Protocols in Patients Undergoing Assisted Reproductive Treatment

(1) Background: In this paper we aim to study the relationship between the expression levels of molecules involved in apoptotic/survival pathways, considered as molecular markers of oocyte competence (i.e., AKT, p-AKT, ERK1/2, and p-ERK1/2) in mural granulosa cells (MGCs) and the administration of r-FSH alone or combined with exogenous r-LH, in ovarian stimulation protocol. Moreover, we aim to evaluate oocyte competence by comparing normally cleaved embryos that were transferred in the uterus, with embryos that were arrested during in vitro culture. (2) Methods: The study included 34 normo-responder women undergoing ICSI procedures. All subjects were divided into two groups. Group A consisted of 18 women stimulated with r-FSH and used as a control group; Group B consisted of 14 women stimulated with r-FSH combined with r-LH. The MGCs were obtained from individual follicles. Immunoblot analyses were carried out to analyze the AKT, p-AKT, ERK1/2, and p-ERK1/2 levels in MGCs and to correlate them with the ovarian stimulation protocol. Furthermore, the oocyte competence was evaluated, for each follicle, according to the development of the embryo during in vitro culture and the pregnancy outcome. (3) Results: We found no significant difference in the levels of molecules in isolated MGCs between groups A and B. These results, in light of our previous research, suggest for the first time, to our knowledge, that cumulus cells and mural granulosa cells in the same follicle show different expression levels of molecules involved in the apoptotic mechanism. (4) Conclusions: Our results could clarify some controversial data in the literature where cumulative cell pools of cumulus and granulosa were analyzed, described as ovarian follicle cells, and used as markers of oocyte competence. In this paper, we found evidence that cumulus and granulosa cells need to be analyzed separately.

Mature oocyte dysmorphisms may be associated with progesterone levels, mitochondrial DNA content, and vitality in luteal granulosa cells

PURPOSE

To identify whether follicular environment parameters are associated with mature oocyte quality, embryological and clinical outcomes.

METHODS

This retrospective study examined 303 mature oocytes from 51 infertile women undergoing ICSI cycles between May 2018 and June 2021. Exclusion criteria consisted of advanced maternal age (> 36 years old), premature ovarian failure, obesity in women, or use of frozen gametes. Luteal granulosa cells (LGCs) were analyzed for mitochondrial DNA/genomic (g) DNA ratio and vitality. The relationships between hormone levels in the follicular fluid and oocyte features were assessed. Quantitative morphometric measurements of mature oocytes were assessed, and the association of LGC parameters and oocyte features on live birth rate after single embryo transfer was examined.

RESULTS

Results indicated an inverse correlation between the mtDNA/gDNA ratio of LGCs and the size of polar body I (PBI). A 4.0% decrease in PBI size was observed with each one-unit increase in the ratio (p = 0.04). Furthermore, a 1% increase in LGC vitality was linked to a 1.3% decrease in fragmented PBI (p = 0.03), and a 1 ng/mL increase in progesterone levels was associated with a 0.1% rise in oocytes with small inclusions (p = 0.015). Associations were drawn among LGC characteristics, perivitelline space (PVS) debris, cytoplasmic inclusions, PBI integrity, and progesterone levels. Certain dysmorphisms in mature oocytes were associated with embryo morphokinetics; however, live birth rates were not associated with follicular parameters and oocyte quality characteristics.

CONCLUSION

Follicular markers may be associated with mature oocyte quality features.

Dysregulation of ferroptosis-related genes in granulosa cells associates with impaired oocyte quality in polycystic ovary syndrome

Background

Poor oocyte quality remains one of the major challenges for polycystic ovary syndrome (PCOS) patients during in vitro fertilization (IVF) treatment. Granulosa cells (GCs) in PCOS display altered functions and could cause an unfavorable microenvironment for oocyte growth and maturation. Ferroptosis is a new form of programmed cell death, but its role in PCOS has been largely unclarified.

Methods

Ferroptosis-related differentially expressed genes (DEGs) of GCs in women with PCOS were identified by bioinformatic analyses of GSE155489 and GSE168404 datasets. Functional enrichment analyses were conducted using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Core ferroptosis-related genes were further screened by random forest, and evaluated for diagnostic value by receiver operating characteristic curve analyses. Gene expression was validated by real-time quantitative polymerase chain reaction of collected GC samples, and analyzed for association with oocyte quality. In addition, gene regulatory network was constructed based on predicted RNA interactions and transcription factors, while potential therapeutic compounds were screened through molecular docking with crystallographic protein structures.

Results

A total of 14 ferroptosis-related DEGs were identified. These DEGs were mainly enriched in reactive oxygen species metabolic process, mitochondrial outer membrane, antioxidant activity as well as ferroptosis and adipocytokine signaling pathways. Eight core ferroptosis-related genes (ATF3, BNIP3, DDIT4, LPIN1, NOS2, NQO1, SLC2A1 and SLC2A6) were further selected in random forest model, which showed high diagnostic performance for PCOS. Seven of them were validated in GC samples, and five were found to be significantly and positively correlated with one or more oocyte quality parameters in PCOS patients, including oocyte retrieval rate, mature oocyte rate, normal fertilization rate, and good-quality embryo rate. Gene regulatory network revealed JUN and HMGA1 as two important transcription factors, while dicoumarol and flavin adenine dinucleotide were predicted as small molecules with therapeutic potential.

Conclusions

This is the first comprehensive report to study the differential expression of ferroptosis-related genes in GCs of PCOS and their clinical relevance with oocyte quality. Our findings could provide novel insights on the potential role of GC ferroptosis in PCOS pathogenesis, diagnosis, and targeted treatment.

Cytoplasmic granules in bovine oocytes do not affect embryonic or fetal development

Oocyte cytoplasmic evaluation is based on homogeneity and granular appearance. Our study investigated if a granular cytoplasm, highly heterogeneous, would affect oocyte competence in bovine. In two experiments, bovine cumulus-oocyte complexes (COCs) with homogeneous cytoplasm (control, CC) and granulated cytoplasm (granular, GC) were selected from a regular pool of COCs. Experiment 1 was performed with slaughterhouse ovaries, and Experiment 2 was carried out in Girolando COCs obtained from ovum pick-up. Granular oocytes had higher caspase 3 levels (66.17 ± 11.61 vs 172.08 ± 16.95, P < 0.01) and similar GAP junction activity (5.64 ± 0.45 vs 6.29 ± 0.29). ZAR1 relative mRNA amount was lower in granular oocytes (178.27 ± 151.63 vs 0.89 ± 0.89, P = 0.01) and no effect was detected for MATER, PPP2R1A, ENY2, IGF2R, and BMP15 genes. Despite molecular differences, no detrimental effect was detected on oocyte competence in GC oocytes. Cleavage (Experiment 1: 59.52 ± 7.21% vs 59.79 ± 6.10% and Experiment 2: 68.88 ± 4.82 vs 74.41 ± 5.89%) and blastocyst (Experiment 1: 29.28 ± 4.14% vs 23.15 ± 2.96% and Experiment 2: 21.11 ± 3.28% vs 21.02 ± 6.08%) rates were similar between CC and GC (Experiments 1 and 2, respectively). Post-transfer embryo development revealed that pregnancy (CC: 24.27 ± 9.70% vs GC: 26.31 ± 7.23%) and calving (23.68% vs 33.33%) rates and fetal growth were not affected by the presence of cytoplasmic granules. Our results demonstrated that oocytes with granular cytoplasm present equivalent efficiency for IVF and calf production compared with homogenous cytoplasm oocytes. This could be observed through similar cleavage, blastocyst rates, and fetal growth development. In addition to differences in oocyte gene expression related to oocyte quality, it seems not to affect oocyte developmental competence.

Structural and metabolic cumulus cell alteration affects oocyte quality in underweight women

This study aimed to investigate the structural and metabolic changes in cumulus cells of underweight women and their effects on oocyte maturation and fertilization. The cytoplasmic ultrastructure was analyzed by electron microscopy, mitochondrial membrane potential by immunofluorescence, and mitochondrial DNA copy number by relative quantitative polymerase chain reaction. The expression of various proteins including the oxidative stress-derived product 4-hydroxynonenal (4-HNE) and autophagy and apoptosis markers such as Vps34, Atg-5, Beclin 1, Lc3-I, II, Bax, and Bcl-2 was assessed and compared between groups. Oocyte maturation and fertilization rates were lower in underweight women (P < 0.05), who presented with cumulus cells showing abnormal mitochondrial morphology and increased cell autophagy. Compared with the mitochondrial DNA copies of the control group, those of the underweight group increased but not significantly. The mitochondrial membrane potential was similar between the groups (P = 0.8). Vps34, Atg-5, Lc3-II, Bax, and Bcl-2 expression and 4-HNE levels were higher in the underweight group compared with the control group (P < 0.01); however, the Bax/Bcl-2 ratio was lower in the underweight group compared with the control group (P = 0.031). Additionally, Beclin 1 protein levels were higher in the underweight group compared with the control group but without statistical significance. In conclusion, malnutrition and other conditions in underweight women may adversely affect ovulation, and the development, and fertilization of oocytes resulting from changes to the intracellular structure of cumulus cells and metabolic processes. These changes may lead to reduced fertility or unsatisfactory reproduction outcomes in women.

The association of RBX1 and BAMBI gene expression with oocyte maturation in PCOS women

BACKGROUND

Polycystic ovarian syndrome (PCOS) is a common endocrine disorder that affects 6-20% of women of reproductive age. One of the symptoms of PCOS is hyperandrogenism, which can impair follicular development. This disruption can cause issues with the development of oocytes and the growth of embryos. Although the exact cause of PCOS is not yet fully understood, studying the gene expression pattern of cumulus cells, which play a crucial role in the maturation and quality of oocytes, could help identify the genes associated with oocyte maturation in PCOS women. Through indirect activation of APC/Cdc20, RBX1 enables oocytes to bypass the GV (germinal vesicles) stage and advance to the MII (metaphase II) stage. our other gene is the BAMBI gene which stimulates WNT signaling, that is a crucial pathway for healthy ovarian function. This study aims to explore the expression level of the RBX1 and BAMBI genes between GV and MII oocytes of PCOS and non-PCOS groups.

METHODS

In this experiment, we gathered the cumulus cells of MII (38 cases and 33 control) and GV (38 cases and 33 control) oocytes from women with/without PCOS. Besides, quantitative RT-PCR was used to assess the semi-quantitative expression of BAMBI and RBX1.

RESULTS

According to our research, the expression level of RBX1 and BAMBI in MII and GV cumulus cells of PCOS patients was significantly lower than that in non-PCOS ones.

CONCLUSION

This research raises the possibility of RBX1 and BAMBI involvement in oocyte quality in PCOS women.

Intra-ovarian inflammatory states and their associations with embryo quality in normal-BMI PCOS patients undergoing IVF treatment

BACKGROUND

Polycystic ovary syndrome (PCOS) is the main cause of anovulatory infertility in women of reproductive age, and low-grade chronic inflammation plays a key role in the occurrence and development of PCOS. However, obesity, as a likely confounding factor, can affect the inflammatory state of PCOS patients.

OBJECTIVE

The aim of this study was to comprehensively investigate intra-ovarian inflammatory states and their impact on embryo quality in PCOS patients with a normal BMI undergoing IVF treatment.

METHODS

DIA-mass spectrometry-based proteomics and bioinformatic analysis were combined to comprehensively profile the protein expression of granulosa cells (GCs) from 5 normal-BMI PCOS patients and 5 controls. Thirty-four cytokines were further systematically detected in follicular fluid (FF) from 32 age- and BMI-matched normal-BMI patients using Luminex liquid chip suspension technology. Next, the differentially expressed cytokines were evaluated by enzyme-linked immunosorbent assay (ELISA) in 24 newly recruited subjects, and the relationship between these cytokines and embryo quality in PCOS patients was analysed. Finally, these cytokine levels were compared and evaluated in PCOS patients with different androgen levels.

RESULTS

Proteomic analysis showed that the suppression of substance metabolism and steroid biosynthesis, more interestingly, resulted in an enhanced immune and inflammatory response in the GCs of normal-BMI PCOS patients and prompted the involvement of cytokines in this process. Luminex analysis further showed that FF macrophage inflammatory protein-1 beta (MIP-1β) and stromal cell-derived factor-1 alpha (SDF-1α) levels were significantly increased in normal-BMI PCOS patients compared to controls (P = 0.005; P = 0.035, respectively), and the ELISA results were consistent with these findings. Besides, FF MIP-1β showed an inverse correlation with the number of D3 good-quality embryos and the good-quality blastocyst rate in patients with PCOS (P = 0.006; P = 0.003, respectively), which remained significant after correction for multiple comparisons. Moreover, SDF-1α levels had no relationship with embryo development in PCOS patients. Additionally, SDF-1α levels were significantly lower in PCOS patients with high androgen levels than in controls (P = 0.031).

CONCLUSIONS

Local ovarian inflammation was present in normal-BMI PCOS patients, affecting follicular development, and FF MIP-1β may be a potential biomarker associated with embryo quality in normal-BMI PCOS patients.

Transcriptomic integrity of human oocytes used in ARTs: technical and intrinsic factor effects

BACKGROUND

Millions of children have been born throughout the world thanks to ARTs, the harmlessness of which has not yet been fully demonstrated. For years, efforts to evaluate the specific effects of ART have focused on the embryo; however, it is the oocyte quality that mainly dictates first and foremost the developmental potential of the future embryo. Ovarian stimulation, cryopreservation, and IVM are sometimes necessary steps to obtain a mature oocyte, but they could alter the appropriate expression of the oocyte genome. Additionally, it is likely that female infertility, environmental factors, and lifestyle have a significant influence on oocyte transcriptomic quality, which may interfere with the outcome of an ART attempt.

OBJECTIVE AND RATIONALE

The objective of this review is to identify transcriptomic changes in the human oocyte caused by interventions specific to ART but also intrinsic factors such as age, reproductive health issues, and lifestyle. We also provide recommendations for future good practices to be conducted when attempting ART.

SEARCH METHODS

An in-depth literature search was performed on PubMed to identify studies assessing the human oocyte transcriptome following ART interventions, or in the context of maternal aging, suboptimal lifestyle, or reproductive health issues.

OUTCOMES

ART success is susceptible to external factors, maternal aging, lifestyle factors (smoking, BMI), and infertility due to endometriosis or polycystic ovary syndrome. Indeed, all of these are likely to increase oxidative stress and alter mitochondrial processes in the foreground. Concerning ART techniques themselves, there is evidence that different ovarian stimulation regimens shape the oocyte transcriptome. The perturbation of processes related to the mitochondrion, oxidative phosphorylation, and metabolism is observed with IVM. Cryopreservation might dysregulate genes belonging to transcriptional regulation, ubiquitination, cell cycle, and oocyte growth pathways. For other ART laboratory factors such as temperature, oxygen tension, air pollution, and light, the evidence remains scarce. Focusing on genes involved in chromatin-based processes such as DNA methylation, heterochromatin modulation, histone modification, and chromatin remodeling complexes, but also genomic imprinting, we observed systematic dysregulation of such genes either after ART intervention or lifestyle exposure, as well as due to internal factors such as maternal aging and reproductive diseases. Alteration in the expression of such epigenetic regulators may be a common mechanism linked to adverse oocyte environments, explaining global transcriptomic modifications.

WIDER IMPLICATIONS

Many IVF factors and additional external factors have the potential to impair oocyte transcriptomic integrity, which might not be innocuous for the developing embryo. Fortunately, it is likely that such dysregulations can be minimized by adapting ART protocols or reducing adverse exposure.

Long pentraxin 3 and vitamin D receptor mRNA expression pattern of cumulus granulosa cells isolated from PCOS oocytes at different stages of nuclear maturation

BACKGROUND

A fine-tuned pro-inflammatory and anti-inflammatory balance in the follicular unit is essential for cumulus expansion and successful ovulation. While the long pentraxin 3 (PTX3) gene is required for the expansion of cumulus cells (CCs), ovulation, resumption of meiosis and fertilization, the vitamin D receptor gene (VDR-X2) is required for intra-follicle redox balance. This study was planned to determine the expression pattern of VDR-X2 and PTX3 mRNA in CCs isolated from germinal vesicle (GV), metaphase I (MI), and metaphase II (MII) oocytes of PCOS patients with ovulatory dysfunction.

METHODS

The relative expression of CC-PTX3 and CC-VDR-X2 mRNA were evaluated using qRT-PCR in a total of 79 CC samples collected from individual cumulus-oocyte complex of 40 infertile patients (20 PCOS and 20 non-PCOS normal responders) who underwent ovarian stimulation with the GnRH antagonist protocol.

RESULTS

Relative PTX3 mRNA expressions of CCMI-control and CCMII-control showed 3- and 9-fold significant upregulation compared to CCGV-control, respectively. The relative PTX3 mRNA expression of CCMII-control increased approximately three fold compared to CCMI-control. Compared to CCGV-pcos, a 3-fold increase was noted in the relative PTX3 mRNA expression of CCMI-pcos and an approximately 4-fold increase in the PTX3 mRNA expression of CCMII-pcos. Relative PTX3 mRNA expression values of CCMII-pcos and CCMI-pcos were similar. A 6-fold upregulation of relative PTX3 mRNA and a 4-fold upregulation of VDR-X2 mRNA were detected in CCMII-control compared to CCMII-pcos. CC-VDR-X2 expression patterns of the PCOS and control groups overlapped with the CC-PTX3 pattern. Fertilization rates of the PCOS group exhibiting failed transcript expression were similar to normal responders.

CONCLUSION

The fact that relative CC-PTX3 and CC-VDR mRNA expression does not increase during the transition from MI to MII stage in PCOS as in normal responders suggests that PTX3 and VDR expression may be defective in cumulus cells of PCOS patients with ovulatory dysfunction.

Effects of stem cell factor in follicular fluid and granulosa cells on oocyte maturity and clinical pregnancy

Stem cell factor (SCF) is implicated in cell growth, proliferation, differentiation, migration, and apoptosis. SCF in follicular fluid (FF) and granulosa cells (GCs) plays a key role in oocyte maturation and clinical pregnancy; however, the exact mechanism is unclear. We aimed to investigate SCF potential in predicting oocyte maturity and clinical pregnancy. We collected 60 FF and 60 GCs samples from different patients with infertility. Real-time polymerase chain reaction and cellular immunofluorescence analyses were used to quantitatively and qualitatively determine SCF concentration in GCs; enzyme-linked immunosorbent assay was used to determine SCF concentration in FF. GC and FF SCF concentrations were positively correlated with metaphase (M)II oocyte proportion and clinical pregnancy (R = 0.280, 0.735 vs R = 0.257, 0.354). SCF concentrations in GCs were significantly higher in the clinical pregnancy group than in the nonclinical pregnancy group. Immunofluorescence analysis showed that SCF expression was higher in the clinical pregnancy and high-MII -oocyte proportion groups. Receiver operating characteristic curve analysis showed that combined SCF and serum anti-Müllerian hormone levels could predict oocyte maturity and clinical pregnancy better than either of these factors alone. SCF concentration in GCs and FF can serve as a predictor of oocyte maturity and clinical pregnancy.

Perfluorooctanoic acid exposure leads to defect in follicular development through disrupting the mitochondrial electron transport chain in granulosa cells

Perfluorooctanoic acid (PFOA) is a persistent environmental pollutant that can impair ovarian function, while the underlying mechanism is not fully understood, and effective treatments are lacking. In this study, we established a mouse model of PFOA exposure induced by drinking water and found that PFOA exposure impaired follicle development, increased apoptosis of granulosa cells (GCs), and hindered normal follicular development in a 3D culture system. RNA-seq analysis revealed that PFOA disrupted oxidative phosphorylation in ovaries by impairing the mitochondrial electron transport chain. This resulted in reduced mitochondrial membrane potential and increased mitochondrial reactive oxygen species (mtROS) in isolated GCs or KGN cells. Resveratrol, a mitochondrial nutrient supplement, could improve mitochondrial function and restore normal follicular development by activating FoxO1 through SIRT1/PI3K-AKT pathway. Our results indicate that PFOA exposure impairs mitochondrial function in GCs and affects follicle development. Resveratrol can be a potential therapeutic agent for PFOA-induced ovarian dysfunction.

Transcriptome Analysis of Granulosa Cells Reveals Regulatory Mechanisms Related to Chicken Follicle Development

In this study, we aimed to better understand the difference between the functions of the two types of granulosa cells and sought to discover more key genes involved in follicle development and follicle selection. Herein, we separately collected pre-hierarchical follicle granulosa cells (PHGCs) and preovulatory follicle granulosa cells (POGCs) for RNA extraction; the transcriptomes of the two groups were compared via RNA-seq. A total of 5273 differentially expressed genes (DEGs) were identified between the PHGCs and POGCs; 2797 genes were up-regulated and 2476 were down-regulated in the PHGCs compared with the POGCs. A qPCR analysis confirmed that the expression patterns of 16 randomly selected DEGs were highly consistent with the RNA-seq results. In the POGCs, many of the genes with the most significant increase in expression were related to steroid hormone synthesis. In addition, the genes with the most significant decline in expression, including AMH and WT1, were related to the inhibition of steroid hormone synthesis. These results suggest that steroid hormones play a key role in follicle development. Furthermore, a Gene Ontology (GO) analysis revealed that these DEGs were mainly involved in the primary metabolic process, the carbohydrate metabolic process, the cellular process, ribosomes, the cytoplasm, and intracellular processes. A Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the DEGs were mainly enriched in steroid biosynthesis, the cell cycle, ribosomes, the TGF-beta signaling pathway, focal adhesion, and so on. We also observed the morphology of the follicles at different developmental stages, and the results showed that the thickness of the granular layer of the small yellow follicles (SYFs) decreased significantly with further development. In addition, we also found that the thickness of the granulosa layer of hens over 300 days old was significantly lower than that of 200-day-old hens. In short, these data indicate that the tissue morphology and function of granulosa cells change throughout follicle development.

HD-sEVs in bovine follicular fluid regulate granulosa cell apoptosis and estradiol secretion through the autophagy pathway

Follicular fluid (FF) is rich in extracellular vesicles (EVs), which have regulatory effects on follicular growth and oocyte development. EVs can be divided into two subtypes, i.e. HD-sEVs and LD-sEVs. In this study, HD-sEVs were successfully isolated from bovine follicular fluid (BFF) by density gradient ultracentrifugation. By western blot, quantitative polymerase chain reaction (qPCR), flow cytometry, transmission electron microscopy (TEM) and enzyme-linked immunosorbent assay (ELISA), this study found HD-sEVs promoted autophagy in bGCs by increasing the protein and mRNA expression of LC3II/LC3I ratio and Beclin1, and inhibiting the protein and mRNA expression of p62. HD-sEVs promoted mitophagy in bGCs by increasing the protein and mRNA expression of VDAC1, CTSD, and HSP60. Flow cytometry showed that HD-sEVs inhibited bGCs apoptosis rate. HD-sEVs promoted estradiol secretion by increasing steroidogenesis-associated proteins and mRNA, such as CYP19A, HSD3B in bGCs. HD-sEVs promoted autophagosome formation and mitochondrial structure swelling in bGCs, and decreased p-mTOR/mTOR ratio. The above phenomenon was reversed when wortmannin was added. Collectively, BFF HD-sEVs promote bGCs autophagy and mitophagy, inhibit bGCs apoptosis and promote estradiol secretion through the autophagy pathway-mTOR signaling pathway.

Essential Role of Granulosa Cell Glucose and Lipid Metabolism on Oocytes and the Potential Metabolic Imbalance in Polycystic Ovary Syndrome

Granulosa cells are crucial for the establishment and maintenance of bidirectional communication among oocytes. Various intercellular material exchange modes, including paracrine and gap junction, are used between them to achieve the efficient delivery of granulosa cell structural components, energy substrates, and signaling molecules to oocytes. Glucose metabolism and lipid metabolism are two basic energy metabolism pathways in granulosa cells; these are involved in the normal development of oocytes. Pyruvate, produced by granulosa cell glycolysis, is an important energy substrate for oocyte development. Granulosa cells regulate changes in intrafollicular hormone levels through the processing of steroid hormones to control the development process of oocytes. This article reviews the material exchange between oocytes and granulosa cells and expounds the significance of granulosa cells in the development of oocytes through both glucose metabolism and lipid metabolism. In addition, we discuss the effects of glucose and lipid metabolism on oocytes under pathological conditions and explore its relationship to polycystic ovary syndrome (PCOS). A series of changes were found in the endogenous molecules and ncRNAs that are related to glucose and lipid metabolism in granulosa cells under PCOS conditions. These findings provide a new therapeutic target for patients with PCOS; additionally, there is potential for improving the fertility of patients with PCOS and the clinical outcomes of assisted reproduction.

Lysophosphatidic acid is associated with oocyte maturation by enhancing autophagy via PI3K-AKT-mTOR signaling pathway in granulosa cells

BACKGROUND

Folliculogenesis is a complex network of interacting cellular signals between somatic cells and oocytes. Many components in ovarian follicular fluid (FF) dynamically change during folliculogenesis and play a positive role in oocyte maturation. Previous studies have reported that lysophosphatidic acid (LPA) promotes cumulus cell expansion, oocyte nuclear maturation, and in vitro maturation of oocytes.

RESULTS

Initially, the expression of LPA was raised in matured FF significantly (P < 0.0001). Then, 10 μM LPA treated for 24 h in human granulosa cells (KGNs) aggravated cell proliferation, with increased autophagy, and reduced apoptosis. Meanwhile, we demonstrated that LPA mediated cell function through the PI3K-AKT-mTOR signaling pathway as PI3K inhibitor (LY294002) significantly prevented LPA-induced AKT, mTOR phosphorylation and autophagy activation. Such results were also verified by immunofluorescence staining and flow cytometry. In addition, an autophagy inhibitor 3 methyladenine (3MA) could also alleviate the effects of LPA, by activating apoptosis through PI3K-AKT-mTOR pathways. Finally, we found blockade with Ki16425 or knockdown LPAR1, alleviated LPA mediated autophagy activation in KGNs, suggesting that LPA enhances autophagy through activation of the LPAR1 and PI3K-AKT-mTOR signaling pathways.

CONCLUSION

This study demonstrates that increased LPA activated PI3K-Akt-mTOR pathway through LPAR1 in granulosa cells, suppressing apoptosis by enhancing autophagy, which might play a role in oocyte maturation in vivo.

The expression levels of NOS2, HMOX1, and VEGFC in cumulus cells are markers of oocyte maturation and fertilization rate

Throughout the reproductive life of women, cumulus cells (CC) protect the dormant oocyte from damage, act as sensors of the follicular microenvironment, and act as a gatekeeper for oocyte developmental potential. One such mechanism relies on the hypoxia-tolerance response, which, with age, decreases systematically, including in the ovary. We aimed to evaluate the association between gene expression related to hypoxia and aging in CC and reproductive results in in vitro fertilization cycles. We recruited 94 women undergoing controlled ovarian stimulation. Total RNA was extracted from pooled CCs collected after oocyte pick-up (OPU) and reverse-transcribed to complementary DNA using random hexamers to test 14 genes related to hypoxia response via HIF1α activation, oxidative stress, and angiogenic responses. The expression of CLU, NOS2, and TXNIP had a positive correlation with age (rs  = 0.25, rs  = 0.24, and rs  = 0.35, respectively). Additionally, NOS2 and HMOX1 expression correlated positively with the retrieval of immature oocytes (rs  = 0.22 and rs  = 0.40, respectively). Moreover, VEGFC levels decreased overall with increasing fertilization rate, independently of age (rs  = -0.29). We found that the fertilization potential of a cohort of oocytes is related to the ability of CC to respond to oxidative stress and hypoxia with age, pointing at NOS2, HMOX1, and VEGFC expression as markers for oocyte maturation and fertilization success.

miR-486 Responds to Apoptosis and Autophagy by Repressing SRSF3 Expression in Ovarian Granulosa Cells of Dairy Goats

The accumulation of ovarian granulosa cell (GC) apoptosis underlies follicular atresia. By comparing the previous sequencing results, miR-486 was found to be differentially expressed at higher levels in the monotocous goat than in the polytocous goat. Unfortunately, the miRNA-mediated mechanisms by which the GC fate is regulated are unknown in Guanzhong dairy goats. Therefore, we investigated miR-486 expression in small and large follicles, as well as its impact on normal GC survival, apoptosis and autophagy in vitro. Here, we identified and characterized miR-486 interaction with Ser/Arg-rich splicing factor 3 (SRSF3) using luciferase reporter analysis, detecting its role in GC survival, apoptosis and autophagy regulation through qRT-PCR, Western blot, CCK-8, EdU, flow cytometry, mitochondrial membrane potential and monodansylcadaverine, etc. Our findings revealed prominent effects of miR-486 in the regulation of GC survival, apoptosis and autophagy by targeting SRSF3, which might explain the high differential expression of miR-486 in the ovaries of monotocous dairy goats. In summary, this study aimed to reveal the underlying molecular mechanism of miR-486 regulation on GC function and its effect on ovarian follicle atresia in dairy goats, as well as the functional interpretation of the downstream target gene SRSF3.

Microenvironmentally Responsive Chemotherapeutic Prodrugs and CHEK2 Inhibitors Self-Assembled Micelles: Protecting Fertility and Enhancing Chemotherapy

Chemotherapy is a widely used and effective adjuvant treatment for cancer, and it has unavoidable damage to female fertility, with statistics showing 38% of women who have received chemotherapy are infertile. How to reduce fertility toxicity while enhancing the oncologic chemotherapy is a clinical challenge. Herein, co-delivery micelles (BML@PMP) are developed, which are composed of a reduction-sensitive paclitaxel prodrug (PMP) for chemotherapy and a CHEK2 inhibitor (BML277) for both fertility protection and chemotherapy enhancement. BML@PMP achieves fertility protection through three actions: (1) Due to the enhanced permeability and retention (EPR) effect, BML@PMP is more enriched in the tumor, while very little in the ovary (about 1/10th of the tumor). (2) Glutathione (GSH) triggers the release of PTX, and with low levels of GSH in the ovary, the amount of PTX released in the ovary is correspondingly reduced. (3) BML277 inhibits oocyte apoptosis by inhibiting the CHEK2-TAp63α pathway. Because of the different downstream targets of CHEK2 in tumor cells and oocytes, BML277 also enhances chemotherapeutic efficacy by reducing DNA damage repair which is activated through the CHEK2 pathway. This bidirectional effect of CHEK2 inhibitor-based co-delivery system represents a promising strategy for improving oncology treatment indices and preventing chemotherapy-associated fertility damage.

Chronic stress decreases fertility parameters in female rats

Multiple effects of stress on health have been reported; however, reproductive alterations in oocytes and cumulus cells have not been fully described. In females, chronic stress has been shown to produce alterations in the estrous cycle, to decrease oocyte in vivo maturation, and to increase the percentage of abnormal oocytes. The aim of this study was to evaluate whether the oocytes from chronically stressed female rats could recover and mature in vitro by providing them with all the necessary culture conditions, as well as to evaluate the functionality of the GAP junctions, and the viability and DNA integrity of the cumulus cells, which are crucial for the complete maturation and development of the oocyte. For this, rats were stressed daily by cold water immersion (15 °C) during 15 min for 30 consecutive days. Corticosterone serum levels in rats increased as an indicator of stress. Chronic stress decreased the percentage of in vitro matured oocytes because the cumulus cells presented irreparable damage to their DNA that led to their death, being unable to establish bidirectional communication with the oocyte for its meiotic resumption through the GAP junctions, which were also damaged. These findings could partially explain an association between stress and infertility.

CiRS-187 regulates BMPR2 expression by targeting miR-187 in bovine cumulus cells treated with BMP15 and GDF9

Circular RNAs (circRNAs) play vital roles in regulating biological processes. However, the contributions of circRNAs to BMPR2 regulation during follicle development remain unknown. In this study, we first verified the optimal conditions for BMP15 and GDF9 treatment in bovine cumulus cells. Then, we screened and identified candidate microRNAs (miRNAs) that may target the BMPR2 3'UTR with TargetScan, a luciferase reporter assay and RT-qPCR. Next, we transfected miR-187 into bovine cumulus cells, and the results showed that miR-187 regulated BMPR2 and inhibited its expression. To explore the competing endogenous RNA (ceRNA) mechanism, we predicted the sponging circRNAs of miR-187 and identified ciRS-187. We further detected miR-187 and BMPR2 expression and apoptosis levels upon knockdown of ciRS-187 and found that ciRS-187 upregulated BMPR2 expression. The results provide a theoretical basis for a ceRNA mechanism of circRNAs related to follicle development.

Impact of the number of retrieved oocytes on IVF outcomes: oocyte maturation, fertilization, embryo quality and implantation rate

The process of oocyte retrieval represents a key phase during the cycles of in vitro fertilization (IVF). It involves controlled ovarian stimulation to retrieve the highest number of oocytes possible. According to many previous studies, the higher the number of oocytes the higher the chances of obtaining embryos for multiple transfers. In this study, in total, 1987 patients were retrospectively reviewed to investigate the correlations between the number of retrieved oocytes and the subsequent IVF outcomes. Patients were divided into three groups according to the number of retrieved oocytes (Group 1: ≤5 oocytes; Group 2: 6-15 oocytes; Group 3: ≥15 oocytes). The results showed a significant negative correlation between oocyte number and maturation rate as well as fertilization rate. However, a significant positive correlation was found between oocyte number and the blastulation rate. The implantation rate after fresh embryo transfers was higher in group 2 (6-15 oocytes) compared with group 1 (≤5 oocytes). According to our findings, we conclude that oocyte numbers between 6 and 15 oocytes can result in the highest chances of positive IVF outcomes in terms of embryo quality and fresh embryo transfers with lower risks of ovarian hyperstimulation.

Comparative effects of retinoic acid, granulosa cells conditioned medium or forskolin in combination with granulosa cell co-culturing on mouse germ cell differentiation

BACKGROUND

Devising of an appropriate in vitro culture method for germ cells differentiation in the presence of soluble factors has attracted considerable attention, which results will provide new insight into reproductive biology. In this study, we compared the effects of forskolin, retinoic acid (RA) or granulosa cell-conditioned medium in the presence or absence of granulosa cell co-culturing on germ cell differentiation from embryonic stem cells (ESCs).

METHODS AND RESULTS

Embryonic stem cells were differentiated using embryoid bodies (EBs) for 5 days, and then EB-derived cells were co-cultured with or without adult mouse granulosa cells using monolayer protocol and treated with 50 µM forskolin, 1 µM RA and 50% granulosa cell-conditioned medium for 4 days. Granulosa cell-conditioned medium significantly increased the levels of Scp3, Rec8, Mvh and Gdf9 expression in the granulosa cell co-culture method compared to untreated cells. A significant elevation of Stra8, Rec8 and Mvh was observed after treatment with RA in the absence of granulosa cells and there was no significant increase in the levels of expression of germ cell-specific genes after treatment with forskolin compared to control. Furthermore, forskolin and RA significantly increased viability and proliferation of germ-like cells, compared with granulosa cell-conditioned medium.

CONCLUSIONS

Our study revealed that granulosa cell-conditioned medium and RA effectively can induce germ cell differentiation from ESCs, however combined application of granulosa cell-conditioned medium and co-culturing with granulosa cells had synergic effect on germ cell development in vitro as optimized protocol.

Distress response in granulosa cells of women affected by PCOS with or without insulin resistance

PURPOSE

In this study, we investigated whether metabolic dysfunction in women with Polycystic ovarian syndrome (PCOS) induces granulosa cell (GC) stress and activates in the endoplamatic reticulum and the mitochondria (UPRer and UPRmt, respectively).

METHODS

Women who were diagnosed with PCOS (based on the Rotterdam criteria), were divided into two groups, PCOS with insulin resistance (PCOS-IR; n = 20) and PCOS with no insulin resistance (PCOS-nIR; n = 20), and compared to healthy oocyte donors (CONT; n = 20). Insulin resistance (IR) was assessed on the results of homeostasis model assessment (HOMA) that determines IR using the concentration of fasting plasma glucose and fasting insuline. Expression of UPRer genes (i.e., IRE1, ATF4, ATF6, XBP1, BIP, and CHOP), and UPRmt genes (i.e., HSP60, HSP10, CLPP, and HSP40) was assessed in cumulus GCs by qRT-PCR.

RESULTS

We found that several genes involved in UPRer and UPRmt were overexpressed in the GCs of PCOS-IR and PCOS-nIR compared to CONT. IRE1, ATF4 and XBP1, that are activated by ER stress, were significantly overexpressed in PCOS-IR compared to CONT. BIP and CHOP were overexpressed in PCOS groups compared to CONT. HSP10 and HSP40 were upregulated in PCOS-IR and PCOS-nIR groups compared to the CONT. HSP60 and CLPP showed no statistical different expression in PCOS-IR and PCOS-nIR compared to CONT group.

CONCLUSION

Our findings suggest that the GCs of women with PCOS (with or without IR) are metabolically distressed and upregulate UPRer and UPRmt genes. Our study contributes to the understanding of the molecular mechanisms underlying the pathological changes that occur in the follicular microenvironment of women with PCOS.

Using Cumulus Cell Biopsy as a Non-Invasive Tool to Access the Quality of Bovine Oocytes: How Informative Are They?

The present study aimed to determine whether cumulus cells (CC) biopsy, acquired before or after in vitro maturation (IVM), presents similar gene expression pattern and if would compromises oocyte quality. First, immature cumulus oocyte complexes (COCs) were distributed: (1) maturated in groups (control); (2) individually maturated, but not biopsied; (3) subjected to CC biopsy before maturation and individually matured; (4) individually matured and submitted to CC biopsy after maturation; (5) individually matured and CC biopsied before and after maturation. Secondly, candidate genes, described as potential markers of COCs quality, were quantified by RT-qPCR in CCs before and after IVM. After in vitro fertilization (IVF), zygotes were tracked and sorted regarding their developmental potential: fully developed to embryo, cleaved and arrested, and not-cleaved. The COC’s biopsy negatively affects embryo development (p < 0.05), blastocyst cell number (p < 0.05), and apoptotic cell ratio (p < 0.05), both before and after IVM. The PTGS2, LUM, ALCAM, FSHR, PGR, SERPINE2, HAS2, and PDRX3 genes were differentially expressed (p < 0.05) on matured CCs. Only PGR gene (p = 0.04) was under-expressed on matured CCs on Not-Cleaved group. The SERPINE2 gene was overexpressed (p = 0.01) in the Cleaved group on immature CCs. In summary, none of the selected gene studies can accurately predict COC’s fate after fertilization.

Seminal extracellular vesicles subsets modulate gene expression in cumulus cells of porcine in vitro matured oocytes

Seminal plasma (SP), a fluid composed mainly by secretions from accessory sex glands, contains a heterogenous population of extracellular vesicles (EVs), involved in several reproductive physiological processes. Seminal plasma has been found to modulate ovary function, in terms of hormone secretion and immune regulation. This study evaluated the potential effect of SP-EV-subsets on the modulation of cumulus-oocyte-complex (COCs) physiology during in vitro maturation (IVM). Two SP-EV-subsets, small-EVs (S-EVs) and large-EVs (L-EVs), were isolated from pig SP by size-exclusion-chromatography. Next, COCs were IVM in the absence (control) or presence of each SP-EV-subset to evaluate their uptake by COCs (PKH67-EVs labelling) and their effect on oocyte and cumulus cells (CCs) (gene expression, and progesterone and estradiol-17β levels). S-EVs and L-EVs were able to bind CCs but not oocytes. Supplementation with L-EVs induced changes (P ≤ 0.05) in the transcript levels of oocyte maturation- (HAS2) and steroidogenesis-related genes (CYP11A1 and HSD3B1) in CCs. No effect on nuclear oocyte maturation and progesterone and estradiol-17β levels was observed when COCs were IVM with any of the two SP-EV-subsets. In conclusion, while SP-EV-subsets can be integrated by CCs during IVM, they do not affect oocyte maturation and only L-EVs are able to modulate CCs function, mainly modifying the expression of steroidogenesis-related genes.

Ginsenoside Rb1 inhibits oxidative stress-induced ovarian granulosa cell injury through Akt-FoxO1 interaction

Ginsenoside Rb1 shows a strong antioxidant effect and has potential activation effects on Akt. The aim of the present study was to investigate the protective effect of Rb1 on age-related ovarian granulosa cell injury. Ovarian granulosa cells (GCs) were obtained from 50 young women (≤30 years) and 50 aged women (≥38 years) at an IVF center. Young and aged ICR mice were administered with or without Rb1 (10 mg kg^-1, i.p.) for 2 weeks. The protective effects of Rb1 were investigated and the role of Rb1 on the modulation of Akt-FoxO1 interaction was determined with immunofluorescence, Western blotting, immunoprecipitation, siRNA silencing and pharmacological inhibitor. Rb1 effectively decreased LDH and MDA, and reversed the apoptotic-related protein levels in hGL cells from old patients. Similar results were found in mice. In addition, the mitochondrial membrane potential was restored and the overaccumulation of ROS was reversed by Rb1. Rb1 preserved peroxide-impaired Akt activation, to some extent, by increasing phosphorylation at Ser473. Rb1 also facilitated p-Akt binding to FoxO1 and promoted the phosphorylation of FoxO1. SiRNA silencing of Akt, Akt inhibitor LY294002, and FoxO1 inhibitor AS1842856 attenuated the effects of Rb1. Ginsenoside Rb1 inhibits age-related GCs oxidative damage by activating Akt phosphorylation at Ser473 and by further interaction with FoxO1.

AIMIC: Deep Learning for Microscopic Image Classification

BACKGROUND AND OBJECTIVE

Deep learning techniques are powerful tools for image analysis. However, the lack of programming experience makes it difficult for novice users to apply this technology. This project aims to lower the barrier for clinical users to implement deep learning methods in microscopic image classification.

METHODS

In this study, an out-of-the-box software, AIMIC (artificial intelligence-based microscopy image classifier), was developed for users to apply deep learning technology in a code-free manner. The platform was equipped with state-of-the-art deep learning techniques and data preprocessing approaches. Furthermore, we evaluated the built-in networks on four benchmark microscopy image datasets to assist entry-level practitioners in selecting a suitable algorithm.

RESULTS

The entire deep learning pipeline, from training a new network to inferring unseen samples using the trained model, could be implemented on the proposed platform without the need for programming. In the evaluation experiments, the ResNeXt-50-32×4d outperformed other competitor algorithms in terms of average accuracy (96.83%) and average F1-score (96.82%). In addition, the MobileNet-V2 achieved a good balance between the performance (accuracy of 95.72%) and computational cost (inference time of 0.109s for identifying one sample).

CONCLUSIONS

The proposed AI platform allows people without programming experience to use artificial intelligence methods in microscopy image analysis. Besides, the ResNeXt-50-32×4d is a preferable solution for microscopic image classification, and MobileNet-V2 is most likely to be an alternative selection for the scenario when computing resources are limited.

Integration analysis of metabolome and transcriptome reveals the effect of exogenous supplementation with mixtures of vitamins ADE, zinc, and selenium on follicular growth and granulosa cells molecular metabolism in donkeys (Equus asinus)

Vitamins and microelements play essential roles in mammalian ovarian physiology, including follicle development, ovulation, and synthesis and secretion of hormones and growth factors. However, it is nevertheless elusive to what extent exogenous supplementation with mixtures of vitamins ADE, zinc (Zn), and selenium (Se) affects follicular growth and granulosa cells (GCs) molecular function. We herein investigated their effect on follicular growth and GCs physiological function. We showed that follicular growth and ovulation time was accelerated and shortened with the increases of vitamins ADE, Zn, and Se doses by continually monitoring and recording (one estrus cycle of about 21 days) with an ultrasound scanner. Integrated omics analysis showed that there was a sophisticated network relationship, correlation expression, and enrichment pathways of the genes and metabolites highly related to organic acids and their derivatives and lipid-like molecules. Quantitative real-time PCR (qPCR) results showed that vitamin D receptor (VDR), transient receptor potential cation channel subfamily m member 6 (TRPM6), transient receptor potential cation channel subfamily v member 6 (TRPV6), solute carrier family 5 member 1 (SLC5A1), arachidonate 5-lipoxygenase (ALOX5), steroidogenic acute regulatory protein (STAR), prostaglandin-endoperoxide synthase 2 (PTGS2), and insulin like growth factor 1 (IGF-1) had a strong correlation between the transcriptome data. Combined multi-omics analysis revealed that the protein digestion and absorption, ABC transporters, biosynthesis of amino acids, aminoacyl-tRNA biosynthesis, mineral absorption, alanine, aspartate and glutamate metabolism, glycine, serine and threonine metabolism, arginine biosynthesis, and ovarian steroidogenesis were significantly enriched. We focused on the gene-metabolite interactions in ovarian steroidogenesis, founding that insulin receptor (INSR), phospholipase a2 group IVA (PLA2G4A), adenylate cyclase 6 (ADCY6), cytochrome p450 family 1 subfamily b member 1 (CYP1B1), protein kinase camp-activated catalytic subunit beta (PRKACB), cytochrome p450 family 17 subfamily a member 1 (CYP17A1), and phospholipase a2 group IVF (PLA2G4F) were negatively correlated with β-estradiol (E2), progesterone (P4), and testosterone (T) (P &lt; 0.05). while ALOX5 was a positive correlation with E2, P4, and T (P &lt; 0.05); cytochrome p450 family 19 subfamily a member 1 (CYP19A1) was a negative correlation with cholesterol (P &lt; 0.01). In mineral absorption, our findings further demonstrated that there was a positive correlation between solute carrier family 26 member 6 (SLC26A6), SLC5A1, and solute carrier family 6 member 19 (SLC6A19) with Glycine and L-methionine. Solute carrier family 40 member 1 (SLC40A1) was a negative correlation with Glycine and L-methionine (P &lt; 0.01). TRPV6 and ATPase Na+/K+ transporting subunit alpha 1 (ATP1A1) were positively associated with Glycine (P &lt; 0.05); while ATPase Na+/K+ transporting subunit beta 3 (ATP1B3) and cytochrome b reductase 1 (CYBRD1) were negatively related to L-methionine (P &lt; 0.05). These outcomes suggested that the vitamins ADE, Zn, and Se of mixtures play an important role in the synthesis and secretion of steroid hormones and mineral absorption metabolism pathway through effects on the expression of the key genes and metabolites in GCs. Meanwhile, these also are required for physiological function and metabolism of GCs. Collectively, our outcomes shed new light on the underlying mechanisms of their effect on follicular growth and GCs molecular physiological function, helping explore valuable biomarkers.

Aspartame Consumption, Mitochondrial Disorder-Induced Impaired Ovarian Function, and Infertility Risk

Frequent consumption of diet drinks was associated with oocyte dysmorphism, decreased embryo quality, and an adverse effect on pregnancy rate. We investigated the harmful effects of aspartame and potential mechanisms through which it increases infertility risk through clinical observations and in vivo and in vitro studies. Methods: We established a cohort of 840 pregnant women and retrospectively determined their time to conceive. We assessed the estrus cycle, the anti-Mullerian hormone level, ovarian oxidative stress, and ovarian mitochondrial function in an animal study. We also evaluated mitochondria function, mitochondrial biogenesis, and progesterone release with in vitro studies. Aspartame consumption was associated with increased infertility risk in the younger women (Odds ratio: 1.79, 95% confidence interval: 1.00, 3.22). The results of the in vivo study revealed that aspartame disrupted the estrus cycle and reduced the anti-Mullerian hormone level. Aspartame treatment also suppressed antioxidative activities and resulted in higher oxidative stress in the ovaries and granulosa cells. This phenomenon is caused by an aspartame-induced decline in mitochondrial function (maximal respiration, spare respiratory capacity, and ATP production capacity) and triggered mitochondrial biogenesis (assessed by examining the energy depletion signaling-related factors sirtuin-1, phosphorylated adenosine monophosphate-activated protein kinase, peroxisome proliferator-activated receptor-gamma coactivator-1α, and nuclear respiratory factor 1 expression levels). Aspartame may alter fertility by reserving fewer follicles in the ovary and disrupting steroidogenesis in granulosa cells. Hence, women preparing for pregnancy are suggested to reduce aspartame consumption and avoid oxidative stressors of the ovaries.

GPX3 Overexpression in Cumulus Cells Entails a Poor Prognosis for Uterine Implantation of Morphotype A Embryos

Morphological embryo quality is an accurate prognostic tool for the success of assisted reproduction implantation, although complete certainty cannot be guaranteed. The transcriptome of the cumulus cells could be monitored as a faithful reflex of the physiological state of the oocytes, given the molecular crosstalk between both types of cells. Here, we compare the expression of specific genes related to oocyte competence, such as hyaluronic acid synthase 2 (HAS2), cell division control protein 42 (CDC42), connexin 43 (CX43), and glutathione peroxidase 3 (GPX3), in cumulus cells from implanted versus non-implanted embryos in 25 women, using RT-qPCR. After embryo transfer, two cohorts were differentiated: the pregnant group (women with the implantation of 100% of embryos transferred) versus the non-pregnant group (with an absence of embryo implantation), aiming to compare the possible differential expression of the selected genes in the cumulus cells of embryos from each group. HAS2, CDC42 and CX43 did not reveal differential expression between the two cohorts. However, GPX3 showed significantly reduced expression in the cumulus belonging to the pregnant group. Interestingly, even cumulus cells belonging only to morphotype A embryos showed a significantly lower expression of GPX3 in the pregnancy group. GPX3 overexpression in cumulus cells could be a poor prognostic indicator of implantation, discriminating beyond the capacity of the morphokinetic score. Unveiling the cumulus transcriptome could improve successful implantation in assisted reproduction treatments.

Metabolic and antioxidant status during transition is associated with changes in the granulosa cell transcriptome in the preovulatory follicle in high-producing dairy cows at the time of breeding

In this study, we hypothesized that early postpartum (pp) metabolic and oxidative stress conditions in dairy cows (particularly those with severe negative energy balance, NEB) are associated with long-term changes in granulosa cell (GC) functions in the preovulatory follicle at the time of breeding. Blood samples were collected at wk 2 and wk 8 pp from 47 healthy multiparous cows. Follicular fluid (FF) and GC were collected from the preovulatory follicle after estrous synchronization at wk 8. Several metabolic and antioxidant parameters were measured in blood and FF, and their correlations were studied. Subsequently, 27 representative GC samples were selected for RNA sequencing analysis. The GC gene expression data of LH-responsive genes and the estradiol:progesterone ratio in FF were used to identify pre- and post-LH surge cohorts. We compared the transcriptomic profile of subgroups of cows within the highest and lowest quartiles (Q4 vs. Q1) of each parameter, focusing on the pre-LH surge cohort (n = 16, at least 3 in each subgroup). Differentially expressed genes (DEG: adjusted P-value < 0.05, 5% false discovery rate) were determined using DESeq2 analysis and were functionally annotated. Blood and FF β-carotene and vitamin E concentrations at wk 2, but not at wk 8, were associated with the most pronounced transcriptomic differences in the GC, with up to 341 DEG indicative for lower catabolism, increased oxidoreductase activity and signaling cascades that are known to enhance oocyte developmental competence, increased responsiveness to LH, and a higher steroidogenic activity. In contrast, elevated blood NEFA concentrations at wk 2 (and not at wk 8) were associated with a long-term carryover effect detectable in the GC transcriptome at wk 8 (64 DEG). These genes are related to response to lipids and ketones, oxidative stress, and immune responses, which suggests persistent cellular stress and oxidative damage. This effect was more pronounced in cows with antioxidant deficiencies at wk 8 (up to 148 DEG), with more genes involved in oxidative stress-dependent responses, apoptosis, autophagy and catabolic processes, and mitochondrial damage. Interestingly, within the severe NEB cows (high blood NEFA at wk 2), blood antioxidant concentrations (high vs. low) at wk 8 were associated with up to 194 DEG involved in activation of meiosis and other signaling pathways, indicating a better oocyte supportive capacity. This suggests that the cow antioxidant profile at the time of breeding might alleviate, at least in part, the effect of NEB on GC functions. In conclusion, these results provide further evidence that the metabolic and oxidative stress in dairy cows early postpartum can have long-term effects on GC functions in preovulatory follicles at the time of breeding. The interplay between the effects of antioxidants and NEFA illustrated here might be useful to develop intervention strategies to minimize the effect of severe NEB on fertility.

Cell-free fat extract improves ovarian function and fertility in mice with premature ovarian insufficiency

Background

Premature ovarian insufficiency (POI) is a refractory disease that seriously affects the reproductive health of women and is increasing in incidence and prevalence globally. There is enormous demand to improve fertility in women with POI, while there is still lack of effective therapeutic methods in clinic. Cell-free fat extract (CEFFE) has been reported to contain thousands of active proteins which possess the ability to promote tissue repair in other diseases. In our study, we aimed to observe the efficacy and biosecurity of CEFFE on the repair of ovarian function and fertility of mice with POI and further explore the underlying mechanism.

Methods

In vivo, POI mice model, established by cyclophosphamide (CTX, 120 mg/kg) and busulfan (BUS, 12 mg/kg), was treated with CEFFE via the tail vein every two days for 2 weeks. Then, the weight of ovaries, estrous cycle and follicle count by H&E staining were measured. The content of AMH, E₂ and FSH in serum was measured by Enzyme-linked immunosorbent assay. Fertility was evaluated by the number of oocytes retrieved, the development of embryos in vitro and the litter size. Biosecurity of parent mice and their pups were examined by body mass and visceral index. The proliferation and apoptosis of cells in ovaries were examined by immunohistochemistry and transmission electron microscopy. Furthermore, the mRNA-Seq of mouse ovarian granulosa cells was performed to explore underlying mechanism of CEFFE. In vitro, KGN cell line and human primary ovarian granulosa cells (hGCs) were treated with 250 μM CTX for 48 h with/without CEFFE. The proliferative ability of cells was detected by cell counting kit-8 assay (CCK-8) and EDU test; the apoptosis of cells was detected by TUNEL and flow cytometry.

Results

CEFFE recovered the content of AMH, E₂ and FSH in serum, increased the number of follicles and the retrieved oocytes of POI mice (P < 0.05). CEFFE contributed to the development of embryos and improved the litter size of POI mice (P < 0.05). There was no side effect of CEFFE on parent mice and their pups. CEFFE contributed to the proliferation and inhibited the apoptosis of mouse granulosa cells in ovary, as well as in human ovarian granulosa cells (including KGN cell line and hGCs) (P < 0.05).

Conclusions

The treatment of CEFFE inhibited the apoptosis of granulosa cells and contributed to the recovery of ovarian function, as well as the fertility of mice with POI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03012-w.

Acupuncture for Female Infertility: Discussion on Action Mechanism and Application

A higher incidence of female infertility has been reported with an unexpectedly early appearance in recent years. The female infertility treatment and application of assisted reproductive technology have recently gained immense interest from scientists. Many studies have discussed the beneficial effects of acupuncture on female infertility. With advancements in science and medical technology, acupuncture-related research has increased in investigating its effectiveness in treating female infertility. This review focuses on a compilation of research in recent years on acupuncture for female infertility treatment and the exploration of the underlying mechanism. For this purpose, literature was searched using various search engines like PubMed, Web of Science, and Google Scholar. The search was refined by only focusing on recent studies on acupuncture effectiveness and mechanism in female infertility and evaluating pregnancy outcomes.

Characterization of histone lysine β-hydroxybutyrylation in bovine tissues, cells, and cumulus-oocyte complexes

Besides their canonical roles as energy sources, short-chain fatty acids act as metabolic regulators of gene expression through histone posttranslational modifications. Ketone body β-hydroxybutyrate (BHB) causes a novel epigenetic modification, histone lysine β-hydroxybutyrylation (Kbhb), which is associated with genes upregulated in starvation-responsive metabolic pathways. Dairy cows increase BHB in early lactation, and the effects of this increase on cellular epigenomes are unknown. We searched for and identified that Kbhb is present in bovine tissues in vivo and confirmed that this epigenetic mark is responsive to BHB in bovine and human fibroblasts cultured in vitro in a dose-dependent manner. Maturation of cumulus-oocyte complexes with high concentrations of BHB did not affect the competence to complete meiotic maturation or to develop until the blastocyst stage. BHB treatment strongly induced H3K9bhb in cumulus cells, but faintly in oocytes. RNA-seq analysis in cumulus cells indicated that BHB treatment altered the expression of 345 genes. The downregulated genes were mainly involved in glycolysis and ribosome assembly pathways, while the upregulated genes were involved in mitochondrial metabolism and oocyte development. The genes and pathways altered by BHB will provide entry points to carry out functional experiments aiming to mitigate metabolic disorders and improve fertility in cattle.

Effects of EGF and melatonin on gene expression of cumulus cells and further in vitro embryo development in bovines

Despite previous research demonstrating the benefits of including growth factors and antioxidants to maturation medium to support embryo production, to date the effect of epidermal growth factor (EGF) and melatonin (Mel) on oocyte competency has not been studied. This study supplemented in vitro maturation (IVM) medium with EGF (10 ng/ml) and Mel (50 ng/ml) alone, or in combination, and evaluated cumulus cell (CC) gene expression and the development and quality of parthenogenetic blastocysts. No differences in CC gene expression levels indicative of developmental potential were found among the treatment groups. Antioxidant gene CuZnSOD was significantly (P < 0.05) decreased in CCs from the Mel group. Moreover, blastocyst rates on day 7 were significantly increased in EGF or Mel (P < 0.05), but not EGF+Mel. Significant decrease (P < 0.05) in GPX1, CuZnSOD, SLC2A1 and HSPA1A (P = 0.07) mRNA levels was observed in blastocysts from the Mel group. OCT4 gene expression was significantly increased (P < 0.05) in EGF+Mel and confirmed using immunofluorescence. Our results indicate that, despite the lack of changes of competence-related genes in CCs, IVM medium supplemented with Mel improved the culture environment sufficiently, resulting in improved blastocysts. Moreover, EGF and Mel combined during maturation increased OCT4 gene and protein expression in blastocysts, indicating its potential for stem cells.

The association between age-related infertility and deoxyribonucleic acid (DNA) integrity parameters of granulosa cells and lymphocytes

This study aimed to investigate the association between deoxyribonucleic acid (DNA) integrity parameters and advanced maternal age (AMA)-related infertility. The granulosa cells and the lymphocytes obtained from 119 infertile women were recruited. Patients were divided into two groups: the AMA group (≥35 years, n = 26) and the non-AMA group (<35 years, n = 93). The tail length, tail moment and tail DNA percentage were evaluated as the DNA integrity parameters using comet assay. Infertility duration (p=.001), luteinising hormone (p=.01) and progesterone levels (p<.0001) were higher and smoking was more prevalent in the AMA group (p=.001). AMA group was stimulated with higher gonadotropin doses (p=.04) and had decreased anti-mullerian hormone levels (p<.0001). All of DNA integrity parameters were distributed homogenously between the groups; however, the tail length of lymphocytes was higher (p=.02) in the AMA group. Fertilisation was lower (p=.02), oocyte quality was tended to be poor (p=.03) and blastocyst transfer was lower in the AMA group (p=.03). Embryo quality was distributed homogenously between the groups. Implantation, clinical pregnancy and live birth rates were similar between the groups. Impact StatementWhat is already known on this subject? Advanced maternal age (AMA)-related infertility is associated with diminished ovarian reserve and alteration in follicular environment resulting in poor oocyte quality; however, the exact pathophysiologic mechanism is not clear.What do the results of this study add? Tail length, tail deoxyribonucleic acid (DNA) percentage, tail moment of granulosa cells were nonsignificantly higher in the AMA group compared to younger patients. All of the DNA integrity parameters of lymphocytes were nonsignificantly higher; however, only tail length of lymphocytes was statistically higher in the AMA group than the non-AMA group. A positive correlation was observed between DNA integrity parameters of lymphocytes and body mass index. There were no correlations between DNA integrity parameters of granulosa cells and lymphocyte and infertility duration, gonadotropin dose, duration of ovarian stimulation, oocyte score, embryo score, basal hormone levels and anti-mullerian hormone levels.What are the implications of these findings for clinical practice and/or further research? Our findings offer new insight for further understanding the role of granulosa cells in mediating the poor reproductive outcome of ageing patients. Understanding the mechanisms of ovarian ageing and poor oocyte quality in women with AMA may help to identify specific targets for improving oocyte quality with ageing.

PTEN expression in human cumulus cells is associated with embryo development competence

Embryo quality determines the success of in vitro fertilization and embryo transfer (IVF-ET) treatment. Biomarkers for the evaluation of embryo quality have some limitations. Apoptosis in cumulus cells (CCs) is important for ovarian function. PTEN (phosphatase and tensin homolog) is a well known tumour suppressor gene that functions as a mediator of apoptosis and is crucial for mammalian reproduction. In the present study, we analyzed the expression level of PTEN in human CCs and aimed to investigate its association with embryo developmental competence in IVF treatment cycles. The PTEN mRNA level in CCs was measured using real-time fluorescence quantitative PCR. The association of the differential expression of PTEN with embryo quality was analyzed. Our data showed that PTEN mRNA levels were significantly decreased in CCs surrounding mature oocytes compared with immature oocytes. Similar changes were found in the analysis of fertilization and blastocyst formation. The speculation that the measurement of PTEN mRNA levels in human CCs would provide a useful tool for selecting oocytes with greater chances to implant into the uterus needs to be further verified through single-embryo transfer in the future. The proapoptotic mechanism of PTEN in human reproduction needs to be further studied.

Comparative analyses in transcriptome of human granulosa cells and follicular fluid micro-environment between poor ovarian responders with conventional controlled ovarian or mild ovarian stimulations

BACKGROUND

Both mild and conventional controlled ovarian stimulation are the frequently used protocols for poor ovarian responders. However, there are some debates about which treatment is better. Moreover, little is known about the follicular physiology after the two ovarian stimulation protocols. This study was intended to investigate the features in granulosa cells and follicular fluid micro-environment after the two different ovarian stimulation protocols in poor responders.

METHODS

Granulosa cells RNA were sequenced using Illumina Hiseq technology. Specific differently expressed genes and proteins were verified by real-time quantitative PCR and Western blot analysis. Moreover, hormone and cytokine concentrations in the follicular fluid were measured by electrochemiluminescence immunoassay and enzyme-linked immunoabsorbent assay. The correlation between the results of molecular experiments and the laboratory outcomes were analyzed by Spearman correlation analysis.

RESULTS

The differentially expressed genes between the two groups were involved in 4 signaling pathways related to the follicular development; three proteins pertinent to the TGF-β signaling pathway were expressed differently in granulosa cells between the two, and the constituents in the follicular fluid were also different. Further, a correlation between the TGF-β signaling pathway and the good-quality embryo was observed.

CONCLUSIONS

The present study made a comparison for the first time in the transcriptome of human granulosa cells and the follicular fluid micro-environment between poor responders with the conventional controlled ovarian stimulation or the mild ovarian stimulation, showing that the TGF-β signaling pathway may correlate with the good-quality of embryos in the mild group, which may be instrumental to the choice of optimal management for IVF patients.

Age-associated changes in cumulus cells and follicular fluid: the local oocyte microenvironment as a determinant of gamete quality

The ovary is the first organ to age in humans with functional decline evident already in women in their early 30s. Reproductive aging is characterized by a decrease in oocyte quantity and quality, which is associated with an increase in infertility, spontaneous abortions, and birth defects. Reproductive aging also has implications for overall health due to decreased endocrinological output. Understanding the mechanisms underlying reproductive aging has significant societal implications as women globally are delaying childbearing and medical interventions have greatly increased the interval between menopause and total lifespan. Age-related changes inherent to the female gamete are well-characterized and include defects in chromosome and mitochondria structure, function, and regulation. More recently, it has been appreciated that the extra-follicular ovarian environment may have important direct or indirect impacts on the developing gamete, and age-dependent changes include increased fibrosis, inflammation, stiffness, and oxidative damage. The cumulus cells and follicular fluid that directly surround the oocyte during its final growth phase within the antral follicle represent additional critical local microenvironments. Here we systematically review the literature and evaluate the studies that investigated the age-related changes in cumulus cells and follicular fluid. Our findings demonstrate unique genetic, epigenetic, transcriptomic, and proteomic changes with associated metabolomic alterations, redox status imbalance, and increased apoptosis in the local oocyte microenvironment. We propose a model of how these changes interact, which may explain the rapid decline in gamete quality with age. We also review the limitations of published studies and highlight future research frontiers.