The human oocyte and cumulus cells relationship: new insights from the cumulus cell transcriptome

Single-cell RNA-seq reveals the effects of the FecB mutation on the transcriptome profile in ovine cumulus cells

Genetic variations in the ovine ovulation rate, which are associated with the FecB mutation, provide useful models by which to explore the mechanisms regulating the development of mammalian antral follicles. In order to study the effects of the FecB mutation on cumulus cell differentiation, preovulatory follicles were aspirated and cumulus cells were isolated from three FecB genotypes (homozygous, heterozygous and wild type) of Small Tail Han (STH) sheep superstimulated with FSH. Transcriptome information from tens of thousands of cumulus cells was determined with the 10 × Genomics single-cell RNA-seq technology. Under the superovulation treatment, the observed number of preovulatory follicles in the ovaries of FecB carriers was still significantly higher than that in the wild-type (P < 0.05). The expression patterns of cumulus cells differed between FecB carriers and wild-type ewes. The screened cumulus cells could also be further divided into different cell clusters, and the differentiation states and fates of each group of cumulus cells also remained different, which supports the notion that heterogeneity in gene expression is prevalent in single cells. The oxidative phosphorylation pathway was significantly enriched in differentially expressed genes among the cell differentiation branch nodes of cumulus cells and among the differentially expressed genes of cumulus cells from the three genotypes. Combined with the important role of oxidative phosphorylation in the maturation of COCs, we suggest that the oxidative phosphorylation pathway of cumulus cells plays a crucial role in the differentiation process of cumulus cells and the mutation effect of the FecB gene.

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.

Curcumin and gallic acid have a synergistic protective effect against ovarian surface epithelium and follicle reserve damage caused by autologous intraperitoneal ovary transplantation in rats

The objective of this study to examine the effects of curcumin and gallic acid use against oxidative stress damage in the autologous intraperitoneal ovarian transplantation model created in rats on ovarian follicle reserve, ovarian surface epithelium, and oxidant-antioxidant systems. 42 adult female Sprague Dawley rats (n=7) were allocated into 6 groups. Group 1 served as the control. In Group 2, rats underwent ovarian transplantation (TR) to their peritoneal walls. Group 3 received corn oil (CO) (0.5 ml/day) one day before and 14 days after transplantation. Group 4 was administered curcumin (CUR) (100 mg/kg/day), Group 5 received gallic acid (GA) (20 mg/kg/day), and Group 6 was treated with a combination of curcumin and gallic acid via oral gavage after transplantation. Rats were sacrificed on the 14th postoperative day, and blood along with ovaries were collected for analysis. The removed ovaries were analyzed at light microscopic, fluorescence microscopic, and biochemical levels. In Group 2 and Group 3, while serum and tissue Total Oxidant Levels (TOS) and Oxidative Stress Index (OSI) increased, serum Total Antioxidant Levels (TAS) decreased statistically significantly (p˂0.05) compared to the other groups (Groups 1, 4, 5, and 6). The ovarian follicle reserve was preserved and the changes in the ovarian surface epithelium and histopathological findings were reduced in the antioxidant-treated groups (Groups 4, 5, and 6). In addition, immunofluorescence examination revealed that the expression of Cytochrome C and Caspase 3 was stronger and Ki-67 was weaker in Groups 2 and 3, in comparison to the groups that were given antioxidants. It can be said that curcumin and gallic acid have a histological and biochemical protective effect against ischemia-reperfusion injury due to ovarian transplantation, and this effect is stronger when these two antioxidants are applied together compared to individual use.

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.

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.

Association between blood lead levels and unfavorable IVF outcomes: potential involvement of endoplasmic reticulum stress response in granulosa cells

PURPOSE

To investigate the relationship between blood lead levels (BLLs) and IVF clinical outcomes in infertile females and to further explore the possible involvement of granulosa cell (GC) endoplasmic reticulum (ER) stress in the process.

METHODS

One hundred twenty-three infertile women undergoing IVF cycles were included in the current study. All participants were divided into three (low, medium, and high) groups determined by BLL tertiles. Gonadotropin releasing hormone (GnRH) agonist regimen for ovarian stimulation was used for all patients, with follicular fluids being collected on the day of oocyte retrieval. Lactate dehydrogenase (LDH) levels in follicular fluid and the endoplasmic reticulum stress-signaling pathway of granulosa cells (GCs) were examined.

RESULTS

The oocyte maturation rate and high-quality embryo rate on cleaved stage decreased significantly as BLL increased. For lead levels from low to high, live birth rate (68.29%, 56.10%, 39.02%; P=0.028) showed negative correlations with BLLs. Also, follicular fluid Pb level and LDH level was significantly higher in the high lead group versus the low group. Binomial regression analysis revealed significant negative correlation between BLLs and live birth rate (adjusted OR, 0.38; 95% CI, 0.15-0.95, P=0.038). Further analysis of the endoplasmic reticulum stress (ER stress) signaling pathway of GCs found that expressions of GRP78, total JNK, phosphorylated JNK, and CHOP increased and BCL-2 decreased with increasing BLLs.

CONCLUSIONS

BLLs are negatively associated with final clinical outcomes in IVF patients that may be related to increased ER stress response and GC apoptosis. Thus, reducing Pb exposure before IVF procedures may improve final success rates.

Notch2 Regulates the Function of Bovine Follicular Granulosa Cells via the Wnt2/β-Catenin Signaling Pathway

Ovarian follicular GCs are strongly implicated in the growth, development, and atresia of ovarian follicles. The Wnt/β-catenin and Notch signaling pathways participate in GC proliferation, differentiation, apoptosis, and steroid hormone production during follicular development. However, the crosstalk between Wnt and Notch signaling in GCs remains unclear. This study investigated this crosstalk and the roles of these pathways in apoptosis, cell cycle progression, cell proliferation, and steroid hormone secretion in bovine follicular GCs. The interaction between β-catenin and Notch2 in GCs was assessed by overexpressing CTNNB1, which encodes β-catenin. The results showed that inhibiting the Notch pathway by Notch2 silencing in GCs arrested the cell cycle, promoted apoptosis, reduced progesterone (P4) production, and inhibited the Wnt2-mediated Wnt/β-catenin pathway in GCs. IWR-1 inhibited Wnt2/β-catenin and Notch signaling, reduced GC proliferation, stimulated apoptosis, induced G1 cell cycle arrest, and reduced P4 production. CTNNB1 overexpression had the opposite effect and increased 17β-estradiol (E2) production and Notch2 protein expression. Co-immunoprecipitation assays revealed that Notch2 interacted with β-catenin. These results elucidate the crosstalk between the Wnt/β-catenin and Notch pathways and the role of these pathways in bovine follicular GC development.

FTO demethylates regulates cell-cycle progression by controlling CCND1 expression in luteinizing goat granulosa cells

In mammals, N6-methyladenosine (m6A) stands out as one of the most abundant internal mRNA modifications and plays a crucial role in follicular development. Nonetheless, the precise mechanism by which the demethylase FTO regulates the progression of the goat luteinizing granulosa cells (LGCs) cycle remains to be elucidated. In our study, we primarily assessed the protein and mRNA expression levels of genes using Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR), cell proliferation via EdU, cell viability with CCK-8, and apoptosis and cell cycle progression through flow cytometry. Here, the results demonstrated that knockdown of FTO significantly enhanced apoptosis, impeded cell proliferation, and increased autophagy levels in goat LGCs. Furthermore, the silencing of FTO substantially reduced cyclin D1 (CCND1) expression through the recognition and degradation of YTHDF2, consequently prolonging the cell cycle progression. This study sheds light on the mechanism by which FTO demethylation governs cell cycle progression by controlling the expression of CCND1 in goat LGCs, underscoring the dynamic role of m6A modification in the regulation of cell cycle progression.

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.

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

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

Transcriptomic profiles reveal the characteristics of oocytes and cumulus cells at GV, MI, and MII in follicles before ovulation

BACKGROUND

The oocyte and its surrounding cumulus cells (CCs) exist as an inseparable entity. The maturation of the oocyte relies on communication between the oocyte and the surrounding CCs. However, oocyte evaluation is primarily based on morphological parameters currently, which offer limited insight into the quality and competence of the oocyte. Here, we conducted transcriptomic profiling of oocytes and their CCs from 47 patients undergoing preimplantation genetic testing for aneuploidy (PGT-A). We aimed to investigate the molecular events occurring between oocytes and CCs at different stages of oocyte maturation (germinal vesicle [GV], metaphase I [MI], and metaphase II [MII]). Our goal is to provide new insights into in vitro oocyte maturation (IVM).

RESULTS

Our findings indicate that oocyte maturation is a complex and dynamic process and that MI oocytes can be further classified into two distinct subtypes: GV-like-MI oocytes and MII-like-MI oocytes. Human oocytes and cumulus cells at three different stages of maturation were analyzed using RNA-seq, which revealed unique transcriptional machinery, stage-specific genes and pathways, and transcription factor networks that displayed developmental stage-specific expression patterns. We have also identified that both lipid and cholesterol metabolism in cumulus cells is active during the late stage of oocyte maturation. Lipids may serve as a more efficient energy source for oocytes and even embryogenesis.

CONCLUSIONS

Overall, our study provides a relatively comprehensive overview of the transcriptional characteristics and potential interactions between human oocytes and cumulus cells at various stages of maturation before ovulation. This study may offer novel perspectives on IVM and provide a reliable reference data set for understanding the transcriptional regulation of follicular maturation.

Fetal hypoxia expose caused autophagy in ovary granulosa cells via PI3K/Akt/FoxO1 pathway and mitigated by melatonin subheading

INTRODUCTION

Fetal hypoxia has long-term effects on postnatal reproductive functions and the mitochondrial impairments of ovarian granulosa cells may be one of the causes. Melatonin applied to mitigate mitochondrial dysfunction and autophagy in mammalian cells has been reported. However, the potential mechanisms by which fetal hypoxia damages reproductive function in neonatal female mice and the melatonin effects on this problem remain unclear.

OBJECTIVES

This research aimed to explore the mechanism that fetal hypoxia damages reproductive function in neonatal female mice and attempt to improve the reproductive function by treating with melatonin in vivo and in vitro.

METHODS

We established a fetal hypoxia model and confirmed that fetal hypoxia affects ovarian function by inducing GC excessive autophagy. Transcriptomic analysis, gene interference, cell immunofluorescence, immunohistochemistry and western blot were conducted to explore and verify the underlying mechanisms in mice GCs and KGN cells. Finally, melatonin treatment was executed on hypoxia-treated mice GCs and KGN cells and melatonin injection to fetal-hypoxia-treated mice to determine its effect.

RESULTS

The results of in vitro experiments found that fetal hypoxia led to mitochondrial dysfunction in ovarian GCs causing autophagic cell death. And the PI3K/Akt/FoxO pathway mediated the occurrence of this process by transcriptome analysis of ovarian GCs from normal and fetal hypoxia mice, which was further verified in mice GCs and KGN cells. Additionally, melatonin administration prevented autophagic injuries and mitochondrial impairments in hypoxia-treated mice GCs and KGN cells. Meanwhile, in vivo experiments by melatonin injection ameliorated oxidative stress of ovary in fetal-hypoxia-treated mice and improved their low fertility.

CONCLUSION

Our data found that fetal hypoxia causes ovarian GCs excessive autophagy leading to low fertility in neonatal female mice and mitigated by melatonin. These results provide a potential therapy for hypoxic stress-related reproductive disorders.

Midkine characterization in human ovaries: potential new variants in follicles

OBJECTIVE

To characterize the growth factor midkine (MDK) in the human ovary to determine whether MDK is produced locally within the ovary, examine whether different ovarian cell types are more likely to produce MDK, and determine whether there are any stage-specific variations during follicle growth. Previous studies have revealed that MDK potentially affects human follicle growth and oocyte maturation. Proteomic analyses in follicular fluid (FF) have identified MDK to functionally cluster together and follow a similar expression profile to that of well-known proteins involved in ovarian follicle development. Midkine has not yet been characterized in the human ovary.

DESIGN

Descriptive study.

SETTING

University Hospital.

PATIENTS

The study included samples from 121 patients: 71 patients (aged 17-37 years) who underwent ovarian tissue cryopreservation provided granulosa cells (GC), cumulus cells, ovarian cortex, medulla tissue, and FF from small antral follicles (SAF); and 50 patients (aged 20-35 years) receiving in vitro fertilization treatment provided FF from preovulatory follicles before and after induction of final follicle maturation.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

MDK relative gene expression was quantified using a real-time quantitative polymerase chain reaction in cumulus cells, GC, and medulla tissue. Additionally, immunostaining and western blotting assays were used to detect MDK protein in the ovarian cortex, which contains preantral follicles, SAF, and medulla tissue. Furthermore, enzyme-linked immunosorbent assay analyses were performed to measure the concentration of MDK in FF aspirated from SAF and preovulatory follicles both before and 36 hours after inducing the final maturation of follicles.

RESULTS

Immunostaining and reverse transcription-quantitative polymerase chain reaction revealed a more prominent expression of MDK in GC compared with other ovarian cell types. Intrafollicular MDK concentration was significantly higher in SAF compared with preovulatory follicles. In addition, different molecular weight species of MDK were detected using western blotting in various ovarian sample types: GC and FF samples presented primarily one band of approximately 15 kDa and an additional band of approximately 13 kDa, although other bands with higher molecular weight (between 30 and 38 kDa) were detected in medulla tissue.

CONCLUSIONS

This is the first time that MDK has been immunolocalized in human ovarian cells at the protein level and that potentially different MDK variants have been detected in human FF, GC, and ovarian medulla tissue. Future studies are needed to sequence and identify the different potential MDK variants found to determine their functional importance for ovary and oocyte competence.

Potential factors result in diminished ovarian reserve: a comprehensive review

The ovarian reserve is defined as the quantity of oocytes stored in the ovary or the number of oocytes that can be recruited. Ovarian reserve can be affected by many factors, including hormones, metabolites, initial ovarian reserve, environmental problems, diseases, and medications, among others. With the trend of postponing of pregnancy in modern society, diminished ovarian reserve (DOR) has become one of the most common challenges in current clinical reproductive medicine. Attributed to its unclear mechanism and complex clinical features, it is difficult for physicians to administer targeted treatment. This review focuses on the factors associated with ovarian reserve and discusses the potential influences and pathogenic factors that may explain the possible mechanisms of DOR, which can be improved or built upon by subsequent researchers to verify, replicate, and establish further study findings, as well as for scientists to find new treatments.

Analysis of Methylome, Transcriptome, and Lipid Metabolites to Understand the Molecular Abnormalities in Polycystic Ovary Syndrome

Purpose

This study aimed to identify differentially methylated genes (DMGs) and differentially expressed genes (DEGs) to investigate new biomarkers for the diagnosis and treatment of polycystic ovary syndrome (PCOS).

Methods

To explore the potential biomarkers of PCOS diagnosis and treatment, we performed methyl-binding domain sequencing (MBD-seq) and RNA sequencing (RNA-seq) on ovarian granulosa cells (GCs) from PCOS patients and healthy controls. MBD-seq was also performed on the ovarian tissue of constructed prenatally androgenized (PNA) mice. Differential methylation and expression analysis were implemented to identify DMGs and DEGs, respectively. The identified gene was further verified by real-time quantitative PCR (RT-qPCR) and methylation-specific PCR (MSP) in clinical samples. Furthermore, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was carried out on PCOS patients and healthy controls to identify differential lipid metabolites.

Results

Compared to the control group, 13,526 DMGs related to the promoter region and 2429 DEGs were found. The function analysis of DMGs and DEGs showed that they were mainly enriched in glycerophospholipid, ovarian steroidogenesis, and other lipid metabolic pathways. Moreover, 5753 genes in DMGs related to the promoter region were screened in the constructed PNA mice. Integrating the DMGs data from PCOS patients and PNA mice, we identified the following 8 genes: CDC42EP4, ERMN, EZR, PIK3R1, ARHGEF18, NECTIN2, TSC2, and TACSTD2. RT-qPCR and MSP verification results showed that the methylation and expression of TACSTD2 were consistent with sequencing data. Additionally, 15 differential lipid metabolites were shown in the serum of PCOS patients. The differential lipids were involved in glycerophospholipid and glycerolipid metabolism.

Conclusion

Using integration of methylome and lipid metabolites profiling we identified 8 potential epigenetic markers and 15 potential lipid metabolite markers for PCOS. Our results suggest that aberrant DNA methylation and lipid metabolite disorders may provide novel insights into the diagnosis and etiology of PCOS.

Exploring molecular dynamic indicators associated with reproductive performance of Bos indicus cattle in blood plasma samples through data-independent acquisition mass spectrometry

Improving reproductive performance of cattle is of paramount importance for sustainable dairy farming. Poor reproduction performance (RP) hinders the genetic improvement of important Bos indicus cattle breeds. It is well known that incorporation of molecular information along with conventional breeding method is far better than use of conventional method alone for the genetic improvement of reproductive performance traits in cattle. Therefore, the present study sought to investigate the plasma proteome of the Deoni cows in cyclical (n = 6) and pregnant (n = 6) reproductive phases with varying reproductive performance (high and low). High-throughput data independent acquisition (DIA) based proteomics was performed to understand corresponding proteome. We identified a total of 430 plasma proteins. Among cyclic cows, twenty proteins were differentially regulated in low RP as compared to high RP. BARD1 and AFP proteins were observed upregulated in cyclical cows whose upregulation reported to affect reproductive performance in cattle. Among the pregnant cows, thirty-five proteins were differentially regulated, including the downregulation of FGL2 and ZNFX1 that modulates the maternal immune response mechanism which is required for successful implantation of the embryo. Also, proteins such as AHSG, CLU and SERPINA6 were upregulated in the pregnant cows whose upregulation reported to reduced reproductive performance. The results of this study will be helpful in establishing a framework for future research on the aspect of improving reproductive performance in Bos indicus cattle breeds. SIGNIFICANCE: The Indian subcontinent is the center of domestication for Bos indicus cattle breeds and they are known for their disease resistance, heat tolerance, ability to survive in low input regime and harsh climatic conditions. In recent times, population of many important Bos indicus breeds including Deoni cattle is declining due to various factors, especially due to reproductive performance. Traditional breeding methods are not sufficient enough to understand and improve the reproductive performance traits in important Bos indicus cattle breeds. Proteomics approach is a promising technology to understand the complex biological factors which leads to poor reproductive performance in cattle. The present study utilized DIA based LC- MS/MS analysis to identify the plasma proteins associated with reproductive performance in cyclical and pregnant cows. This study if improved further, can be used to develop potential protein markers associated with reproductive performance which is useful for the selection and genetic improvement of important Bos indicus breeds.

A Role of PI3K/Akt Signaling in Oocyte Maturation and Early Embryo Development

A serine/threonine-specific protein kinase B (PKB), also known as Akt, is a key factor in the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway that regulates cell survival, metabolism and proliferation. Akt phosphorylates many downstream specific substrates, which subsequently control the nuclear envelope breakdown (NEBD), centrosome maturation, spindle assembly, chromosome segregation, and cytokinesis. In vertebrates, Akt is also an important player during oogenesis and preimplantation development. In the signaling pathways regulating mRNA translation, Akt is involved in the control of mammalian target of rapamycin complex 1 (mTORC1) and thereby regulates the activity of a translational repressor, the eukaryotic initiation factor 4E (eIF4E) binding protein 1 (4E-BP1). In this review, we summarize the functions of Akt in mitosis, meiosis and early embryonic development. Additionally, the role of Akt in the regulation of mRNA translation is addressed with respect to the significance of this process during early development.

Effect of Growth Factors and Hormones during In Vitro Growth Culture of Cumulus-Oocyte-Complexes Derived from Small Antral Follicles in Pigs

This study evaluated the effect of various growth factors and hormones in an in vitro growth (IVG) medium on the in vitro maturation (IVM) and developmental competence of oocytes derived from small antral follicles (SAFs) in pigs. Cumulus–oocyte complexes (COCs) derived from SAFs were either untreated or treated with epidermal growth factor (EGF), insulin-like factor-1 (IGF-1), insulin, or growth hormone (GH) for 2 days of IVG. Following IVG, COCs were cultured for maturation, and IVM oocytes were induced for parthenogenesis (PA). During IVG, the nuclear maturation of oocytes was significantly increased by the insulin treatment compared to other treatments. Moreover, the insulin treatment significantly increased blastocyst formation after PA relative to the No-IVG, control, EGF, and GH treatments. The cumulus expansion score after IVG-IVM was significantly higher in the insulin group than in the other groups. The glutathione (GSH) contents in IVM oocytes were increased through treatment with IGF, insulin, and GH compared to those of No-IVG oocytes. The level of reactive oxygen species (ROS) in IVM oocytes in all treatment groups was significantly lower after IVG culture than in the No-IVG group. The maturation-promoting factor (MPF) activity after IVM in the insulin-treated oocytes was significantly higher than that of the oocytes treated with EGF, IGF-1, and GH. In conclusion, this study demonstrates that insulin treatment during IVG culture improves the maturational and developmental competence of oocytes derived from SAFs in pigs through its effect on cumulus cell expansion and cytoplasmic microenvironments, such as GSH, ROS, and MPF activity.

Bioinformatic Analysis of Human Cumulus Cells to Unravel Cellular's Processes that Could Be Used to Establish Oocyte Quality Biomarkers with Clinical Application

Metadata analysis of public microarray datasets using bioinformatics tools has been successfully used in several biomedical fields in the search for biomarkers. In reproductive science, there is an urgent need for the establishment of oocyte quality biomarkers that could be used in the clinical environment to increase the chances of successful outcomes in treatment cycles. Adaptive cellular processes observed in cumulus oophorus cells reflect the conditions of the follicular microenvironment and may thus bring relevant information of oocyte's conditions. Here we analyzed human cumulus cells gene expression datasets in search of predictors of oocyte quality, a strategy which uncovered several cellular processes positively and negatively associated with embryo development and pregnancy potential. Secondly, the expression levels of genes that were present in the majority of processes observed were validated in house with clinical samples. Our data confirmed the association of the selected biomarkers with blastocyst formation and pregnancy potential rates, independently of patients' clinical characteristics such as diagnosis, age, BMI, and stimulation protocol applied. This study shows that bioinformatic analysis of cellular processes can be successfully used to elucidate possible oocyte quality biomarkers. Our data reinforces the need to consider clinical characteristics of patients when selecting relevant biomarkers to be used in the clinical environment and suggests a combination of positive (PTGS2) and negative (CYPB1) quality biomarkers as a robust strategy for a complementary oocyte selection tool, potentially increasing assisted reproduction success rates. Also, GPX4 expression as pregnancy potential biomarker is indicated here as a possibility for further investigations.

Local regulation of antral follicle development and ovulation in monovulatory species

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

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.

Cutting-edge techniques provide insights regarding repeated implantation failure patients

RESEARCH QUESTION

Can time-lapse parameters and the transcriptional profile of cumulus cells be used to achieve a more stringent and non-invasive method of embryo assessment and to identify possible factors affecting the embryo's ability to implant in repeated implantation failure (RIF) patients?

DESIGN

A total of 190 embryos from 18 oocyte donors and 145 embryos from 15 RIF patients were evaluated based on time-lapse parameters. Three morphokinetic parameters including T5 (time to reach five cells), T3 (time to reach three cells) and CC2 (time to two to three cells) were recorded for all embryos. Embryos that had all three parameters in the normal range were graded as high quality and comparison between these parameters were compared in high-quality embryos between two groups. The transcriptional profile of cumulus cells related to high-quality embryos of both groups were analysed by RNA sequencing and compared. Finally, the possible relationship between differentially expressed genes and time-lapse parameters was examined.

RESULTS

T5 was significantly lower in the RIF group than the donor group (P = 0.011). The cumulus cell transcriptome analysis showed 193 genes were down-regulated and 222 genes up-regulated. The mammalian target of rapamycin and the transforming growth factor beta pathways were significantly increased in the RIF group compared to the donor group (P = 0.007 and 0.01, respectively). Vitamin B12 and fatty acid beta-oxidation pathways were also significantly reduced in the RIF group compared to the donor group (P = 0.006 and 0.01, respectively).

CONCLUSIONS

Differences in the transcriptomic profiles of cumulus cells and some morphokinetic parameters may be one of the main factors contributing to unexplained RIF.

Microfluidic devices employing chemo- and thermotaxis for sperm selection can improve sperm parameters and function in patients with high DNA fragmentation

Conventional sperm processing uses centrifugation has a negative effect on sperm parameters and DNA integrity. We designed and fabricated a novel microfluid device based on chemotaxis and thermotaxis, and compared it with the swim-up method. Twenty normal samples with high DNA fragmentation were included. Each sample was divided into four groups: Group 1, control, Group 2: sperm selection by thermotaxis, Group 3: sperm selection by chemotaxis, and Group 4: sperm selection with thermotaxis and chemotaxis. We used cumulus cells in a microfluid device to create chemotaxis, and, two warm stages to form a temperature gradient for thermotaxis. The spermatozoa were assessed based on the concentration, motility, and fine morphology using Motile Sperm Organelle Morphology Examination, mitochondrial membrane potential (MMP), acrosome reaction (AR), and sperm DNA fragmentation. Concentration (22.40 ± 5.39 vs. 66.50 ± 19.21; p < 0.001) and DNA fragmentation (12.30 ± 3.96% vs. 17.95 ± 2.89%; p < 0.001) after selection in the chemotaxis and thermotaxis microfluid device were significantly lower than control group. The progressive motility (93.75 ± 4.39% vs. 75.55 ± 5.86%, p < 0.001), normal morphology (15.45 ± 2.50% vs. 10.35 ± 3.36, p < 0.001), MMP (97.65 ± 1.81% vs. 94 ± 3.89%, p = 0.02), and AR status (79.20 ± 5.28% vs. 31.20 ± 5.24%, p < 0.001) in the chemotaxis and thermotaxis microfluid device were significantly increased compared to control group. According to these findings, spermatozoa that have penetrated the cumulus oophorus have better morphology and motility, as well as acrosome reactivity and DNA integrity.

TBX2 affects proliferation, apoptosis and cholesterol generation by regulating mitochondrial function and autophagy in bovine cumulus cell

BACKGROUND

T-box transcription factor 2 (TBX2) is a member of T-box gene family whose members are highly conserved in evolution and encoding genes and are involved in the regulation of developmental processes. The encoding genes play an important role in growth and development. Although TBX2 has been widely studied in cancer cell growth and development, its biological functions in bovine cumulus cells remain unclear.

OBJECTIVES

This study aimed to investigate the regulatory effects of TBX2 in bovine cumulus cells.

METHODS

TBX2 gene was knockdown with siRNA to clarify the function in cellular physiological processes. Cell proliferation and cycle changes were determined by xCELLigence cell function analyzer and flow cytometry. Mitochondrial membrane potential and autophagy were detected by fluorescent dye staining and immunofluorescence techniques. Western blot and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) were used to detect the expression changes of proliferation and autophagy-related proteins. Aadenosine triphosphate (ATP) production, glucose metabolism, and cholesterol synthesis of cumulus cells were measured by optical density and chemiluminescence analysis.

RESULTS

After inhibition of TBX2, the cell cycle was disrupted. The levels of apoptosis, ratio of light chain 3 beta II/I, and reactive oxygen species were increased. The proliferation, expansion ability, ATP production, and the amount of cholesterol secreted by cumulus cells were significantly decreased.

CONCLUSIONS

TBX2 plays important roles in regulating the cells' proliferation, expansion, apoptosis, and autophagy; maintaining the mitochondrial function and cholesterol generation of bovine cumulus cells.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Trehalose Suppresses Lysosomal Anomalies in Supporting Cells of Oocytes and Maintains Female Fertility

Supporting cells of oocytes, i.e., cumulus cells, control oocyte quality, which determines fertilization success. Therefore, the transformation of mature and immature cumulus cells (MCCs and ICCs, respectively) into dysmature cumulus cells (DCCs) with dead characteristics deteriorates oocyte quality. However, the molecular basis for this transformation remains unclear. Here, we explored the link between autophagic decline and cumulus transformation using cumulus cells from patients with infertility, female mice, and human granulosa cell-derived KGN cell lines. When human cumulus cells were labeled with LysoTracker probes, fluorescence corresponding to lysosomes was enhanced in DCCs compared to that in MCCs and ICCs. Similarly, treatment with the autophagy inhibitor chloroquine elevated LysoTracker fluorescence in both mouse cumulus cells and KGN cells, subsequently suppressing ovulation in female mice. Electron microscopy analysis revealed the proliferation of abnormal lysosomes in chloroquine-treated KGN cells. Conversely, the addition of an autophagy inducer, trehalose, suppressed chloroquine-driven problematic lysosomal anomalies and ameliorated ovulation problems. Our results suggest that autophagy maintains the healthy state of the supporting cells of human oocytes by suppressing the formation of lysosomes. Thus, our results provide insights into the therapeutic effects of trehalose on female fertility.

Progesterone-Induced Sperm Release from the Oviduct Sperm Reservoir

In mammalian females, after sperm are deposited in the reproductive tract, a fraction of sperm migrates to the lower oviduct (isthmus) and forms a sperm storage site known as the functional sperm reservoir. The interactions between sperm membrane proteins and oviduct epithelial cells facilitate sperm binding to the oviductal epithelium and retention in the reservoir. Sperm are bound by glycans that contain specific motifs present on isthmic epithelial cells. Capacitated sperm are released from the reservoir and travel further in the oviduct to the ampulla where fertilization occurs. For decades, researchers have been studying the molecules and mechanisms of sperm release from the oviductal sperm reservoir. However, it is still not clear if the release of sperm is triggered by changes in sperm, oviduct cells, oviduct fluid, or a combination of these. While there is a possibility that more than one of these events are involved in the release of sperm from the reservoir, one activator of sperm release has the largest accumulation of supporting evidence. This mechanism involves the steroid hormone, progesterone, as a signal that induces the release of sperm from the reservoir. This review gathers and synthesizes evidence for the role of progesterone in inducing sperm release from the oviduct functional sperm reservoir.

L-Cysteine improves bovine oocyte developmental competence in vitro via activation of oocyte-derived growth factors BMP-15 and GDF-9

This study was designed to investigate the effect of different concentrations of L-cysteine supplementation into the maturation medium on the oocyte nuclear maturation, cumulus cell expansion, ultrastructure of the oocytes and the expression of oocyte-derived growth factors BMP-15, GDF-9 and CB-1 genes. Cumulus oocyte complexes (COCs) were collected from cow's ovaries obtained from abattoir and incubated at 38.5°C in maturation media supplemented with 0, 0.6, 0.8 or 1 mM L-cysteine in 5% CO₂ under humidified air for 24 hr. We found that a significantly higher percentage of oocytes progressed to metaphase II stage in the in vitro maturation (IVM) medium supplemented with L-cysteine, particularly 0.8 mM group, compared with untreated control oocytes. Additionally, L-cysteine treatment significantly increased the number of expanded COCs and the degree of expansion of individual COCs. Results of RT-qPCR showed significant increase in expression levels of BMP-15 and GDF-9 in L-cysteine-treated groups compared with control one. Electron microgram showed improvement of cytoplasmic maturation regarding ultrastructure of the oocytes and oocyte-cumulus cell gap junction communication in all L-cysteine-treated groups especially 0.8 mM L-cysteine-treated one. In conclusion, supplementation of IVM medium with a potential anti-oxidant, L-cysteine can effectively improve in vitro oocytes cytoplasmic and nuclear maturation via activation of oocyte maturation related BMP-15 and GDF-9 genes in bovine oocytes, benefiting the extended researches about the potential applications of L-cysteine in mammalian breeding technologies.

Phosphoglycerate mutase family member 5 maintains oocyte quality via mitochondrial dynamic rearrangement during aging

Decline in ovarian reserve with aging is associated with reduced fertility and the development of metabolic abnormalities. Once mitochondrial homeostasis is imbalanced, it may lead to poor reproductive cell quality and aging. However, Phosphoglycerate translocase 5 (PGAM5), located in the mitochondrial membrane, is associated with necroptosis, apoptosis, and mitophagy, although the underlying mechanisms associated with ovarian aging remain unknown. Therefore, we attempted to uncover whether the high phosphoglycerate mutant enzyme family member 5 (PGAM5) expression is associated with female infertility in cumulus cells, and aims to find out the underlying mechanism of action of PGAM5. We found that PGAM5 is highly expressed and positively associated with aging, and has the potential to help maintain and regulate mitochondrial dynamics and metabolic reprogramming in aging granulosa cells, ovaries of aged female mice, and elderly patients. PGAM5 undergoes activation in the aging group and translocated to the outer membrane of mitochondria, co‐regulating DRP1; thereby increasing mitochondrial fission. A significant reduction in the quality of mitochondria in the aging group, a serious imbalance, and a significant reduction in energy, causing metabolism shift toward glycolysis, were also reported. Since PGAM5 is eliminated, the mitochondrial function and metabolism of aging cells are partially reversed. A total of 70 patients undergoing in vitro fertilization (IVF) treatment were recruited in this clinical study. The high expression of PGAM5 in the cumulus cells is negatively correlated with the pregnancy rate of infertile patients. Hence, PGAM5 has immense potential to be used as a diagnostic marker.

Role of EGFR expressed on the granulosa cells in the pathogenesis of polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is one of the most common endocrinological disorders affecting between 6 to 20% of reproductive aged women. However, the etiology of PCOS is still unclear. Epidermal growth factor receptor (EGFR) plays a critical role in the growth and development of ovarian follicles. In our previous study, we showed that the expression level of EGFR was significantly higher in the cumulus granulosa cells from women with PCOS than that of normal women, suggesting that EGFR may play a potential role in the pathogenesis of PCOS. The present study further evaluated the association between EGFR and PCOS through both in clinical observation and animal experiments. We firstly validated the differential expression of EGFR in cumulus granulosa cells between PCOS patients and normal subjects by qRT-PCR and immunofluorescence staining. Then we generated a mouse model (n=20) of PCOS by injecting dehydroepiandrosterone (DHEA). The PCOS mice were then injected with an E corpus GFR inhibitor (AG1478) (n=10), which significantly improved the sex hormone levels in the estrous cycle stage, and the serum levels of LH, FSH and testosterone were compared with the PCOS mice without EGFR inhibitor treatment (n=10). Decreasing the expression level of EGFR in the PCOS mice also improved the ovulatory function of their ovaries which was indicated by the multifarious follicle stage in these mice as compared with the PCOS mice without EGFR inhibitor treatment. Also, the number of corpopa lutea were higher in the control group and the EGFR inhibitor treated group than in the PCOS group. The sex hormone levels and reproductive function were not significantly different between the control mice and the PCOS mice treated with the EGFR inhibitor. Our results demonstrated that EGF/EGFR signaling affected the proliferation of cumulus granulosa cells, oocyte maturation and meiosis, and played a potential role in the pathogenesis of PCOS. Therefore, the selective inhibition of EGFR may serve as a novel strategy for the clinical management of PCOS.

Extensive analysis of mitochondrial DNA quantity and sequence variation in human cumulus cells and assisted reproduction outcomes

STUDY QUESTION

Are relative mitochondrial DNA (mtDNA) content and mitochondrial genome (mtGenome) variants in human cumulus cells (CCs) associated with oocyte reproductive potential and assisted reproductive technology (ART) outcomes?

SUMMARY ANSWER

Neither the CC mtDNA quantity nor the presence of specific mtDNA genetic variants was associated with ART outcomes, although associations with patient body mass index (BMI) were detected, and the total number of oocytes retrieved differed between major mitochondrial haplogroups.

WHAT IS KNOWN ALREADY

CCs fulfil a vital role in the support of oocyte developmental competence. As with other cell types, appropriate cellular function is likely to rely upon adequate energy production, which in turn depends on the quantity and genetic competence of the mitochondria. mtDNA mutations can be inherited or they can accumulate in somatic cells over time, potentially contributing to aging. Such mutations may be homoplasmic (affecting all mtDNA in a cell) or they may display varying levels of heteroplasmy (affecting a proportion of the mtDNA). Currently, little is known concerning variation in CC mitochondrial genetics and how this might influence the reproductive potential of the associated oocyte.

STUDY DESIGN, SIZE, DURATION

This was a prospective observational study involving human CCs collected with 541 oocytes from 177 IVF patients. mtDNA quantity was measured in all the samples with a validated quantitative PCR method and the entire mtGenome was sequenced in a subset of 138 samples using a high-depth massively parallel sequencing approach. Associations between relative mtDNA quantity and mtGenome variants in CCs and patient age, BMI (kg/m2), infertility diagnosis and ART outcomes were investigated.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Massively parallel sequencing permitted not only the accurate detection of mutations but also the precise quantification of levels of mutations in cases of heteroplasmy. Sequence variants in the mtDNA were evaluated using Mitomaster and HmtVar to predict their potential impact.

MAIN RESULTS AND THE ROLE OF CHANCE

The relative mtDNA CC content was significantly associated with BMI. No significant associations were observed between CC mtDNA quantity and patient age, female infertility diagnosis or any ART outcome variable. mtGenome sequencing revealed 4181 genetic variants with respect to a reference genome. The COXI locus contained the least number of coding sequence variants, whereas ATPase8 had the most. The number of variants predicted to affect the ATP production differed significantly between mitochondrial macrohaplogroups. The total number of retrieved oocytes was different between the H-V and J-T as well as the U-K and J-T macrohaplogroups. There was a non-significant increase in mtDNA levels in CCs with heteroplasmic mitochondrial mutations.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Although a large number of samples were analysed in this study, it was not possible to analyse all the CCs from every patient. Also, the results obtained with respect to specific clinical outcomes and macrohaplogroups should be interpreted with caution due to the smaller sample sizes when subdividing the dataset.

WIDER IMPLICATIONS OF THE FINDINGS

These findings suggest that the analysis of mtDNA in CCs is unlikely to provide an advantage in terms of improved embryo selection during assisted reproduction cycles. Nonetheless, our data raise interesting biological questions, particularly regarding the interplay of metabolism and BMI and the association of mtDNA haplogroup with oocyte yield in ovarian stimulation cycles.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by National Institutes of Health grant 5R01HD092550-02. D.J.N. and C.R. co-hold patent US20150346100A1 and D.J.N. holds US20170039415A1, both for metabolic imaging methods. D.W. receives support from the NIHR Oxford Biomedical Research Centre. The remaining authors have no conflicts of interest to declare.

Hypoxia: Role of SIRT1 and the protective effect of resveratrol in ovarian function

Background

Ovarian function is closely related to the degree of vascular network development surrounding the ovary. Maternal aging‐related construction defects in this vascular network can cause ovarian hypoxia, which impedes oocyte nutrient supply, leading to physiological changes in the ovaries and oocytes. The anti‐aging gene Sirtuin 1 (SIRT1) senses and adapts to ambient stress and is associated with hypoxic environments and mitochondrial biogenesis.

Methods

The present study is a literature review focusing on investigations involving the changes in SIRT1 and mitochondrial expression during hypoxia and the cytoprotective effects of the SIRT1 activator, resveratrol.

Main findings

Hypoxia suppresses SIRT1 and mitochondrial expression. Resveratrol can reverse the hypoxia‐induced decrease in mitochondrial and SIRT1 activity. Resveratrol suppresses the production of hypoxia‐inducible factor‐1α and vascular endothelial growth factor proteins.

Conclusion

Resveratrol exhibits protective activity against hypoxic stress and may prevent hypoxia‐ or aging‐related mitochondrial dysfunction. Resveratrol treatment may be a potential option for infertility therapy.

Impact of Cigarette Smoking on the Expression of Oxidative Stress-Related Genes in Cumulus Cells Retrieved from Healthy Women Undergoing IVF

The female reproductive system represents a sensitive target of the harmful effects of cigarette smoke, with folliculogenesis as one of the ovarian processes most affected by this exposure. The aim of this study was to analyze the impact of tobacco smoking on expression of oxidative stress-related genes in cumulus cells (CCs) from smoking and non-smoking women undergoing IVF techniques. Real time PCR technology was used to analyze the gene expression profile of 88 oxidative stress genes enclosed in a 96-well plate array. Statistical significance was assessed by one-way ANOVA. The biological functions and networks/pathways of modulated genes were evidenced by ingenuity pathway analysis software. Promoter methylation analysis was performed by pyrosequencing. Our results showed a down-regulation of 24 genes and an up-regulation of 2 genes (IL6 and SOD2, respectively) involved in defense against oxidative damage, cell cycle regulation, as well as inflammation in CCs from smoking women. IL-6 lower promoter methylation was found in CCs of the smokers group. In conclusion, the disclosed overall downregulation suggests an oxidant-antioxidant imbalance in CCs triggered by cigarette smoking exposure. This evidence adds a piece to the puzzle of the molecular basis of female reproduction and could help underlay the importance of antioxidant treatments for smoking women undergoing IVF protocols.

CD147 deficiency is associated with impairedsperm motility/acrosome reaction and offersa therapeutic target for asthenozoospermia

Patients with asthenozoospermia often present multiple defects in sperm functions apart from a decrease in sperm motility. However, the etiological factors underlying these multifaceted defects remain mostly unexplored, which may lead to unnecessary treatment and unsatisfactory assisted reproductive technologies (ART) outcome. Here, we show that the protein levels of CD147 were lowered in sperm obtained from asthenozoospermic infertile patients exhibiting defects in both sperm motility and the acrosome reaction. Whereas CD147 maintained sperm motility before capacitation, female tract-derived soluble CD147 interacted with sperm-bound CD147 to induce an acrosome reaction in capacitated sperm. Soluble CD147 treatment restored the acrosome reaction and improved the fertility of sperm from patients with asthenozoospermia. Mechanistically, CD147 promotes sperm motility and acrosome reaction (AR) by eliciting Ca²⁺ influx through soluble CD147 binding to sperm-bound CD147. Notably, the level of soluble CD147 in seminal plasma was positively correlated with the fertilization rate and pregnancy outcome in infertile couples undergoing in vitro fertilization. Our study has identified a marker for the diagnosis and a therapeutic target for the defective AR capability in asthenozoospermia and a candidate for the prediction of in vitro fertilization outcomes for male infertile patients that facilitates the development of precision medicine in ART.

Cumulus cell microRNA expression when LH is added to the ovarian stimulation protocol: a pilot study

RESEARCH QUESTION

Recombinant FSH administration in ovarian stimulation for IVF is a standard procedure, whereas the role of LH is controversial. MicroRNAs (mRNA) are small endogenous non-coding transcripts that are involved in the regulation of many cellular processes, including foliculogenesis and gonadotrophin function. The aim was to study the possible role of miRNA in ovarian follicular development in groups having different ovarian stimulation protocols. Are there different miRNA expression profiles in cumulus cells of infertile women undergoing IVF? What are the regulated pathways?

DESIGN

This prospective observational study included 13 patients who fulfilled the following inclusion criteria: younger than 38 years of age; a tubal infertility factor; a male factor; or idiopathic infertility. This is a pilot study in which the patients were aleatory enrolled into two groups: seven in FSH group (recombinant FSH, 225 IU) and six in FSH plus LH group (recombinant FSH, 150 IU + recombinant LH, 75 IU). The granulosa cells obtained from the follicular ovarian retrieval were analysed using polyerase chain reaction. Results were analysed using DIANA Tools, an online bioinformatics tool.

RESULTS

Among the 84 microRNAs evaluated, 11 were differentially expressed between the groups, all of which were upregulated in the FSH plus LH group, compared with the FSH group. Differentially expressed miRNA profiles are related to oestrogen signalling, oocyte meiosis and pluripotent cells regulation.

CONCLUSION

miRNA overexpression in the FSH plus LH group is consistent with the independent and fundamental role of LH in folliculogenesis, leading to a distinct molecular response between groups.

Mitochondria-related changes and metabolic dysfunction in low prognosis patients under the POSEIDON classification

STUDY QUESTION

What is the relationship between mitochondria of granulosa cells (GCs) and age and ovarian function in the patients under the POSEIDON classification?

SUMMARY ANSWER

Our results revealed obvious abnormal mitochondrial-related changes in low prognosis IVF population, where age and the function of ovarian reserve exerted a divergent effect on mitochondrial content and function.

WHAT IS KNOWN ALREADY

Mitochondria have an important role in the cross-talk between GCs and oocytes. However, factors affecting mitochondria of GCs and related mechanisms are still poorly understood.

STUDY DESIGN, SIZE, DURATION

GCs samples were obtained from 119 infertile women undergoing IVF from September 2020 to February 2021. Six groups were investigated by the POSEIDON stratification: young with normal prognosis (C1), aging with normal prognosis (C2), young and low prognosis group with normal ovarian reserve (NOR) (G1), aging and low prognosis group with NOR (G2), young and low prognosis group with diminished ovarian reserve (DOR) (G3), and aging and low prognosis group with DOR (G4).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The morphology of GC mitochondria was observed by transmission electron microscopy. MtDNA copy number and mitochondrial replication-related genes were detected by real-time quantitative PCR (qPCR). Mitochondrial membrane potential (MMP) and cytosolic reactive oxygen species (ROS) were detected by confocal microscopy. Cellular glycolysis and aerobic respiratory capacity were analyzed by Seahorse XFe96 Analyzer, and related gene expression and protein levels were assessed by qPCR and Western blot.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to the normal prognosis groups, mitochondrial morphology was impaired in the low prognosis groups, where the young groups (G1, G3) with low prognosis showed phenotypes undergoing oxidative stress (round, vacuolated, swollen with decreased matrix density) and the aging groups (G2, G4) revealed typical aging characteristics (an irregular shape with heterogeneous matrix density and cord-like cristae). Additionally, the degree of corresponding change and damage was more obvious in patients with DOR (G3, G4) regardless of age. For mitochondrial content, the mtDNA copy number in GCs was significantly negatively correlated with age in the low prognosis groups (β = -0.373, P = 0.005). Interestingly, the relationship between mtDNA copy number and anti-Mullerian hormone score differed between the two age groups with low prognosis, with a negative correlation in the young groups (β = -0.639, P = 0.049) and a positive correlation in the aging groups (β = 0.505, P = 0.039). In addition, significantly reduced mitochondrial activity (MMP, ROS) and cell metabolism (both glycolysis and OXPHOS) were observed in the low prognosis groups, with the most obvious decrease being observed in the DOR population. However, the metabolism of the GCs in normal prognosis aging women (C2) shifted from OXPHOS to anaerobic glycolysis.

LIMITATIONS, REASONS FOR CAUTION

Owing to the difficulties involved in primary GC collection and culture, the sample size was limited.

WIDER IMPLICATIONS OF THE FINDINGS

Mitochondrial abnormality is closely linked to the low prognostic outcome in IVF patients. Supplementing the functional mitochondrial content or improving mitochondrial function by autologous mitochondrial transfer or mitochondrial-related regulating drugs may help improve the clinical outcomes in patients with a low prognosis, especially for those with DOR.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (No. 21737001), the Peking University Clinical Medicine + X Youth Project (PKU2020LCXQ011), the Research and Development Program of Peking University People's Hospital (No. RDH2017-03; No. RDX2019-06) and the Application of Clinical Features of Capital Special Subject (Z171100001017130). There were no competing interests.

TRIAL REGISTRATION NUMBER

This study was registered with the Chinese Clinical Trial Register (Clinical Trial Number: ChiCTR2100045531).

Effects of demethylase KDM4B on the biological characteristics and function of yak cumulus cells in vitro

The present study aims to investigate the expression and function of lysine-specific demethylase 4B (KDM4B) in yak cumulus cells (CCs) in order to reveal the mechanisms by which KDM4B regulates biological characteristics and function of CCs. The cellular location of KDM4B and the methylation pattern of H3K9 were detected using immunofluorescence (IF) staining in CCs. The mRNA expression levels of apoptosis-related genes (BCL-2, HAX1 and BAX) and genes related to the estrogen pathway (ESR2, CYP17 and 3B-HSD) were estimated by qRT-PCR after knockdown of KDM4B expression by siRNA in yak CCs. Then, a proliferation assay, Annexin V-FITC staining, and ELISA were utilized to explore the effects of KDM4B silencing on CCs proliferation, apoptosis, and estrogen (E₂) secretion, respectively. The results showed that KDM4B is located in the nuclei of yak CCs and is distributed in a dotted pattern. Knockdown KDM4B induced a decrease in cell proliferation, an increase in apoptotic rate and a reduction in the levels of E₂ secretion of CCs. Additionally, the methylation patterns of H3K9me2 and H3K9me3 were significantly increased in CCs transfected with KDM4B siRNA-1 (P < 0.05). The mRNA expression level of apoptosis promoting BAX genes was significantly upregulated, but 3B-HSD, ESR2 and anti-apoptotic HAX1 genes were significantly downregulated in transfected CCs (P < 0.05). Furthermore, the rate of embryos developing from the 2-cell stage to blastocysts was lower in the siRNA-1 transfection group than that of the control group (28.6 ± 2.9% vs 40.4 ± 2.4%, P < 0.05). In conclusion, our study indicates that KDM4B regulates the biological characteristics and physiological function of yak CCs mainly through changing the methylation patterns of H3K9 and related gene expression levels.

Accompaniment of Time-Lapse Parameters and Cumulus Cell RNA-Sequencing in Embryo Evaluation

The aim of this study was to investigate the use of time-lapse morphokinetic parameters and cumulus cells transcriptomic profile to achieve a more accurate and non-invasive method in embryo evaluation. Two hundred embryos from 20 couples were evaluated based on morphokinetic characteristics using time-lapse. Embryos were divided into the high-quality, moderate-quality, and bad-quality groups. Non-fertilized oocytes were considered as the fourth group. T5 (time to five cells), S2 (time from three to four cells), and CC2 (time from two to three cells) were recorded. Also, the cumulus cells of the respective oocytes were divided into high-quality, moderate-quality, bad-quality, and non-fertilized groups based on the grading of the embryos. Then their transcriptomic profiles were analyzed by RNA-sequencing. Finally, the correlation between differentially expressed genes and embryo time-lapse parameters was investigated. T5 was the only timing that showed a statistically significant difference between high-quality group and other groups. RNA-sequencing results showed that 37 genes were downregulated and 106 genes were upregulated in moderate, bad-quality, and non-fertilized groups compared to high-quality group (q value < 0.05). These genes were involved in the main biological processes such as cell cycle, DNA repair, cell signaling and communication, transcription, and cell metabolism. Embryos graded in different groups showed different transcriptomic profiles in the related cumulus cells. Therefore, it seems that embryo selection using the combination of cytokinetics and cumulus cells gene expression can improve the accuracy of the embryo selection and pregnancy rate in ART clinics.

Tannin Supplementation Improves Oocyte Cytoplasmic Maturation and Subsequent Embryo Development in Pigs

To investigate the effects of tannins (TA) on porcine oocyte in vitro maturation (IVM), different concentrations of TA (0, 1, 10 and 100 μg/mL) were supplemented with a maturation medium and the COCs and subsequent embryonic development were examined. The results showed that 10 µg/mL TA significantly improved the cumulus expansion index (CEI), cumulus-expansion-related genes (PTGS1, PTGS2, PTX-3, TNFAIP6 and HAS2) expression and blastocyst formation rates after parthenogenetic activation (PA), in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) compared to the control groups, but not oocyte nuclear maturation. Nevertheless, 10 µg/mL TA dramatically enhanced the mRNA expression of oocyte-development-related genes (BMP15, GDF9, CDC2 and CYCLIN B1), GSH, ATP, SOD1, PGC1α, BMP15, GDF9 and CDC2 levels and reduced intracellular ROS level in porcine oocytes. These results indicated that porcine oocyte cytoplasmic maturation was improved by 10 µg/mL TA treatment during IVM. In contrast, a high concentration of TA (100 μg/mL) significantly decreased the CEI and PTGS1, PTGS2, PTX-3 and HAS2 mRNA expressions in cumulus cells, and reduced oocyte nuclear maturation and the total cell numbers/blastocyst. In general, these data showed that 10 μg/mL TA supplementation has beneficial effects on oocyte cytoplasmic maturation and subsequent embryonic development in pigs.

Upregulation of Low-Density Lipoprotein Receptor of the Steroidogenesis Pathway in the Cumulus Cells Is Associated with the Maturation of Oocytes and Achievement of Pregnancy

The maturation of the oocyte is influenced by cumulus cells (CCs) and associated with pregnancy rate, whereas the influencing factors have not been completely elucidated in the CCs. In this study, we identified new regulators of CCs for high-quality oocytes and successful pregnancies during assisted reproductive techniques. CCs were collected from cumulus–oocyte complexes (COCs) in young (≤33 years old) and old (≥40 years old) women undergoing intracytoplasmic sperm injection (ICSI) procedures. We screened for factors differentially expressed between young vs. old CCs and pregnancy vs. non-pregnancy using whole mRNA-seq-next-generation sequencing (NGS). We characterized the transcriptome of the CCs to identify factors critical for achieving pregnancy in IVF cycles. Women in the young and old pregnancy groups exhibited the up- and downregulation of multiple genes compared with the non-pregnancy groups, revealing the differential regulation of several specific genes involved in ovarian steroidogenesis in CCs. It was shown that the low-density lipoprotein (LDL) receptor to the steroidogenesis pathway was upregulated in CCs with higher maturity rates of oocytes in the pregnancy group. In conclusion, a higher pregnancy rate is related to the signaling pathway of steroidogenesis by the LDL receptor in infertile women undergoing IVF procedures.

Comparing mRNA and sncRNA profiles during the maternal-to-embryonic transition in bovine IVF and scNT embryos

Production of embryos with high developmental competence by somatic cell nuclear transfer (scNT) is far less efficient than for in vitro fertilized (IVF) embryos, likely due to an accumulation of errors in genome reprogramming that results in aberrant expression of RNA transcripts, including messenger RNAs (mRNA) and, possibly, microRNAs (miRNA). Thus, our objectives were to use RNAseq to determine the dynamics of mRNA expression in early developing scNT and IVF embryos in the context of the maternal-to-embryonic transition (MET) and to correlate apparent transcriptional dysregulation in cloned embryos with miRNA expression profiles. Comparisons between scNT and IVF embryos indicated large scale transcriptome differences, which were most evident at the 8-cell and morula stages for genes associated with biological functions critical for the MET. For two miRNAs previously identified as differentially expressed in scNT morulae, miR-34a and miR-345, negative correlations with some predicted mRNA targets were apparent, though not widespread among the majority of predicted targets. Moreover, although large-scale aberrations in expression of mRNAs were evident during the MET in cattle scNT embryos, these changes were not consistently correlated with aberrations in miRNA expression at the same developmental stage, suggesting that other mechanisms controlling gene expression may be involved.

The Function of Cumulus Cells in Oocyte Growth and Maturation and in Subsequent Ovulation and Fertilization

Cumulus cells (CCs) originating from undifferentiated granulosa cells (GCs) differentiate in mural granulosa cells (MGCs) and CCs during antrum formation in the follicle by the distribution of location. CCs are supporting cells of the oocyte that protect the oocyte from the microenvironment, which helps oocyte growth and maturation in the follicles. Bi-directional communications between an oocyte and CCs are necessary for the oocyte for the acquisition of maturation and early embryonic developmental competence following fertilization. Follicle-stimulation hormone (FSH) and luteinizing hormone (LH) surges lead to the synthesis of an extracellular matrix in CCs, and CCs undergo expansion to assist meiotic resumption of the oocyte. The function of CCs is involved in the completion of oocyte meiotic maturation and ovulation, fertilization, and subsequent early embryo development. Therefore, understanding the function of CCs during follicular development may be helpful for predicting oocyte quality and subsequent embryonic development competence, as well as pregnancy outcomes in the field of reproductive medicine and assisted reproductive technology (ART) for infertility treatment.

Metabolic imaging of human cumulus cells reveals associations among metabolic profiles of cumulus cells, patient clinical factors, and oocyte maturity

OBJECTIVE

To determine whether fluorescence lifetime imaging microscopy (FLIM) detects differences in metabolic state among cumulus cell samples and whether their metabolic state is associated with patient age, body mass index (BMI), and antimüllerian hormone (AMH) level and maturity of the oocyte.

DESIGN

Prospective observational study.

SETTING

Academic laboratory.

PATIENT(S)

Cumulus cell (CC) clusters from cumulus-oocyte complexes were collected from patients undergoing assisted reproductive technology treatment after oocyte retrieval and vitrified.

INTERVENTION(S)

Cumulus cell metabolism was assessed using FLIM to measure autofluorescence of nicotinamide adenine (phosphate) dinucleotide and flavine adenine dinucleotide, endogenous coenzymes essential for cellular respiration and glycolysis. Patient age, BMI, and AMH level and the maturity of the corresponding oocytes were recorded.

MAIN OUTCOME MEASURE(S)

Quantitative information from FLIM was obtained regarding metabolite concentrations from fluorescence intensity and metabolite enzyme engagement from fluorescence lifetimes. Associations were investigated between each FLIM parameter and oocyte maturity and patient age, BMI, and AMH. Variance between CC clusters within and between patients was determined.

RESULT(S)

Of 619 CC clusters from 193 patients, 90 were associated with immature oocytes and 505 with metaphase II oocytes. FLIM enabled quantitative measurements of the metabolic state of CC clusters. These parameters were significantly correlated with patient age and AMH independently, but not with BMI. Cumulus cell nicotinamide adenine (phosphate) dinucleotide FLIM parameters and redox ratio were significantly associated with maturity of the enclosed oocyte.

CONCLUSION(S)

FLIM detects variations in the metabolic state of CCs, showing a greater variance among clusters from each patient than between patients. Fluorescence lifetime imaging microscopy can detect CC metabolic associations with patient age and AMH and variations between mature and immature oocytes, suggesting the potential utility of this technique to help identify superior oocytes.

Extracellular vesicles of bovine small follicular fluid promote ovarian cortical stromal cell proliferation and steroidogenesis

The aim of this study was to investigate the effects of extracellular vesicles (EVs) on the proliferation and steroid hormone synthesis of bovine ovarian cortical stromal cells in vitro. The release and uptake of EVs are the new mechanisms of cell-to-cell communication. Using reverse transcriptase polymerase chain reaction, enzyme-linked immunosorbent assay, TUNEL and other experiments, we found that EVs in bovine follicular fluid can promote the proliferation and synthesis of androstenedione and progesterone in ovarian cortical stromal cells. Moreover, 100 μg/ml EVs caused the most significant effect. We conclude that EVs at 100 μg/ml can significantly promote the proliferation and synthesis of androstenedione and progesterone in ovarian cortical stromal cells. This research is of great significance for further elucidating the regulatory role of follicular fluid EVs in follicular development and atresia and for research on the interaction of ovarian stromal cells, granulosa cells and oocytes.

Mitochondrial enrichment in infertile patients: a review of different mitochondrial replacement therapies

Poor ovarian responders exhibit a quantitative reduction in their follicular pool, and most cases are also associated with poor oocyte quality due to patient’s age, which leads to impaired in vitro fertilisation outcomes. In particular, poor oocyte quality has been related to mitochondrial dysfunction and/or low mitochondrial count as these organelles are crucial in many essential oocyte processes. Therefore, mitochondrial enrichment has been proposed as a potential therapy option in infertile patients to improve oocyte quality and subsequent in vitro fertilisation outcomes. Nowadays, different options are available for mitochondrial enrichment treatments that are encompassed in two main approaches: heterologous and autologous. In the heterologous approach, mitochondria come from an external source, which is an oocyte donor. These techniques include transferring either a portion of the donor’s oocyte cytoplasm to the recipient oocyte or nuclear material from the patient to the donor’s oocyte. In any case, this approach entails many ethical and safety concerns that mainly arise from the uncertain degree of mitochondrial heteroplasmy deriving from it. Thus the autologous approach is considered a suitable potential tool to improve oocyte quality by overcoming the heteroplasmy issue. Autologous mitochondrial transfer, however, has not yielded as many beneficial outcomes as initially expected. Proposed mitochondrial autologous sources include immature oocytes, granulosa cells, germline stem cells, and adipose-derived stem cells. Presently, it would seem that these autologous techniques do not improve clinical outcomes in human infertile patients. However, further trials still need to be performed to confirm these results. Besides these two main categories, new strategies have arisen for oocyte rejuvenation by improving patient’s own mitochondrial function and avoiding the unknown consequences of third-party genetic material. This is the case of antioxidants, which may enhance mitochondrial activity by counteracting and/or preventing oxidative stress damage. Among others, coenzyme-Q10 and melatonin have shown promising results in low-prognosis infertile patients, although further randomised clinical trials are still necessary.

Notch signaling pathway in cumulus cells reflecting zygote and embryo quality in polycystic ovary syndrome

PURPOSE

The present study aimed to explore the associations between the expression pattern of molecules in the Notch pathway in the cumulus cells of polycystic ovary syndrome (PCOS) patients and the quality of zygotes and embryos.

METHODS

A total of 200 cumulus complexes surrounding mature oocytes were obtained from 40 patients with and without PCOS undergoing intracytoplasmic sperm injection (ICSI). The expressions of Notch-1, Notch-2, and Notch-3 genes were examined by Reverse Transcription Q-PCR assay. Moreover, immunocytochemistry was performed for the expressions of Jagged-1 and Jagged-2 proteins. The correlations between the Notch receptors and their ligand expressions and the qualities of the zygote and embryo were investigated.

RESULTS

The expression levels of Notch-2, Notch-3, Jagged-1, and Jagged-2 were significantly lower in patients with PCOS than in normal women (p < 0.05), while Notch-1 showed no meaningful difference between the groups. A positive correlation was found between Notch-1 and embryo quality. Furthermore, only Notch-2 and Jagged-2 marginally correlated with zygote quality.

CONCLUSION

The data of the present study indicated that evaluating the molecules in the Notch pathway in PCOS patients' cumulus cells provides a novel approach to predict the zygote and embryo quality. However, further studies on a larger population are needed to validate this finding.