Cumulus Cells Research Articles

Cumulus cell DNA damage linked to fertilization success in females with an ovulatory dysfunction phenotype

Intracytoplasmic sperm injection (ICSI) is a widely used technique in fertility centers. ICSI success depends on both nuclear and cytoplasmic oocyte maturation. Cumulus cells, which surround the oocytes, play a pivotal role in oocyte competence. However, the significance of DNA damage in cumulus cells as a marker of fertilization success remains largely unexplored. This study aims to investigate the relationship between DNA damage in cumulus cells of females undergoing ICSI, and oocyte competence, with a focus on in vitro fertilization (IVF) outcomes. We employed the alkaline comet assay to assess DNA damage levels (%TDNA) in cumulus cells and whole blood from 22 potentially fertile females and 35 infertile females, including 20 with an ovulatory disfunction phenotype. Our results revealed significant differences between the levels of %TDNA in cumulus cells and blood. Females with an ovulatory dysfunction phenotype exhibited higher levels of %TDNA in cumulus cells compared to potentially fertile females. Additionally, within the group of females with ovulatory dysfunction, a significant correlation was observed between %TDNA levels and the number of oocytes with two pronuclei. Our findings suggest that blood does not accurately reflect DNA damage in cumulus cells, which was correlated with the fertilization success in females with ovulatory dysfunction. High levels of %TDNA in cumulus cells were associated with a higher likelihood of successful fertilization. Moreover, our results imply that low levels of %TDNA may be linked to oocytes that fail to complete maturation and, consequently, do not fertilize (oocytes with zero pronuclei). Further research with larger cohorts is necessary to validate these findings and to explore potential applications in female fertility. However, our study provides evidence that DNA damage in cumulus cells may serve as a valuable biomarker for predicting fertilization success and oocyte competence.

Excess Weight Impairs Oocyte Quality, as Reflected by mtDNA and BMP-15

This prospective, case-control study evaluated the impact of obesity on oocyte quality based on mtDNA expression in cumulus cells (CC), and on bone morphogenetic protein 15 (BMP-15) and heparan sulfate proteoglycan 2 (HSPG2) in follicular fluid (FF). It included women 18 to <40 years of age, divided according to BMI < 24.9 (Group 1, n = 28) and BMI > 25 (Group 2, n = 22). Demographics, treatment, and pregnancy outcomes were compared. The mtDNA in CC, BMP-15, HSPG2, the lipid profile, the hormonal profile, and C-reactive protein were evaluated in FF and in blood samples. The BMP-15 levels in FF and the mitochondrial DNA in CC were higher in Group 1 (38.8 ± 32.5 vs. 14.3 ± 10.8 ng/mL; p = 0.001 and 1.10 ± 0.3 vs. 0.87 ± 0.18-fold change; p = 0.016, respectively) than in Group 2. High-density lipoprotein levels in blood and FF were higher in Group 1 (62 ± 18 vs. 50 ± 12 mg/dL; p = 0.015 and 34 ± 26 vs. 20.9 ± 7.2 mg/dL; p = 0.05, respectively). Group 2 had higher blood C-reactive protein (7.1 ± 5.4 vs. 3.4 ± 4.3 mg/L; p = 0.015), FF (5.2 ± 3.8 vs. 1.5 ± 1.6 mg/L; p = 0.002) and low-density lipoprotein levels (91 ± 27 vs. 71 ± 22 mg/dL; p = 0.008) vs. Group 1. Group 1 demonstrated a trend toward a better clinical pregnancy rate (47.8% vs. 28.6%: p = 0.31) and frozen embryo transfer rate (69.2% vs. 53.8; p = 0.69). Higher BMI resulted in lower BMP-15 levels and reduced mtDNA expression, which reflect decreased oocyte quality in overweight women.

AREG expression in cumulus cells as a prognostic marker of oocyte quality

Background. Assisted reproductive technologies (ART) represent the most promising and successful methods of infertility treatment. A personalized approach may enhance its efficacy. One such approach is the development of reliable methods for assessing the quality and selection of embryos for transfer. The quality of the embryo is largely contingent upon the quality of the gametes involved in fertilization; thus, the development of non-invasive methods to assess oocyte quality represents a crucial step in the advancement of personalized ART. It is proposed that molecular and biological characterization of cumulus cells can be utilized to assess oocyte quality and predict the success of implantation of transferred embryos. The aim of the study was to evaluate the expression levels of potential oocyte quality marker genes (AREG, STAR, PTGS2, HAS2 and SCD5) in cumulus cells from healthy donors and patients with primary and secondary infertility. Materials and Methods. Nine donors and 19 patients were enrolled in the study. RNA was isolated from cumulus cells obtained during oocyte preparation for fertilization, and cDNA was synthesized. The cDNA was used as a matrix for real-time PCR with primers for the above-mentioned genes of interest. Results. Significant difference in AREG gene expression was observed between patients with successful (i.e. ended with birth) outcome and with IVF failure. No difference was found for the STAR, HAS2, PTGS2 and SCD5 genes. Conclusion. The method of assessing the expression level of marker genes in cumulus cells by real-time PCR shows considerable promise for the assessment of oocyte quality. The AREG gene is a potential candidate for use as a marker of oocyte quality.

Effect of biphasic in vitro maturation (CAPA-IVM) on EGF receptor and embryo development of prepubertal goat oocytes according to follicle size

Oocytes spontaneously resume meiosis following their liberation from follicles, preventing full competence acquisition. Biphasic IVM (CAPA-IVM) maintains oocytes in meiotic arrest to improve developmental competence, and it specially affects poorly developed oocytes. We assessed the effect of CAPA-IVM on oocytes from small (<3mm) and large (>3mm) follicles of prepubertal goats. Oocytes were cultured for 6h in pre-IVM with C-type natriuretic peptide (CNP) and estradiol as meiotic inhibitors, and germinal vesicle (GV) rate and chromatin configuration were assessed. Then, oocytes were cultured in conventional IVM (c-IVM) or CAPA-IVM (pre-IVM + c-IVM) and EGF receptor (EGFR) protein expression, intra-oocyte ROS and blastocyst development were assessed. GV rate was higher in CNP groups than control (69% vs 28%, and 67% vs 31%, small and large follicles, respectively), but GV chromatin configuration was similar. In large follicles, EGFR expression was higher in oocytes and cumulus cells after CAPA-IVM, and ROS levels were lower. In small follicles these differences were not observed. c-IVM and CAPA-IVM produced similar blastocyst rates in small (3.7% vs 2.6%, respectively) and large follicles (8.3% vs 2.5%). Overall, CAPA-IVM enhanced EGFR expression for EGF peptide signalling and antioxidant capacity in oocytes from large follicles but oocytes from small follicles were too immature to benefit from it.

Melatonin supplementation attenuates cuproptosis and ferroptosis in aging cumulus and granulosa cells: potential for improving IVF outcomes in advanced maternal age

BackgroundAdvanced maternal age is associated with decreased oocyte quantity and quality and in vitro fertilization (IVF) success rates. This study aimed to investigate whether melatonin supplementation can improve IVF outcomes in women of advanced maternal age by modulating cuproptosis and ferroptosis.MethodsThis prospective cohort study included 161 women aged 35–45 years undergoing IVF-frozen embryo transfer cycles. Participants were assigned to either melatonin (n = 86, 2 mg daily for ≥ 8 weeks) or control (n = 75) groups. Cumulus cells were analyzed for cuproptosis and ferroptosis-related gene expression. Additional experiments were conducted on the HGL5 human granulosa cell line to assess mitochondrial function and metabolic reprogramming.ResultsMelatonin supplementation significantly improved IVF outcomes in women aged ≥ 38 years, increasing clinical pregnancy rates (46.0% vs. 20.3%, P < 0.01), ongoing pregnancy rates (36.5% vs. 15.3%, P < 0.01), and live birth rates (33.3% vs. 15.3%, P < 0.05). In cumulus cells from patients, gene expression analysis revealed that melatonin modulated cuproptosis and ferroptosis-related genes, including ATP7B and GPX4, with more pronounced effects in the ≥ 38 years group. This suggests melatonin enhances cellular resilience against oxidative stress and metal-induced toxicity in the ovarian microenvironment. In vitro studies using HGL5 cells showed melatonin reduced oxidative stress markers, improved mitochondrial function, restored expression of glycolysis and TCA cycle-related genes and modulated cuproptosis and ferroptosis-related gene expression. These findings provide mechanistic insight into melatonin’s protective effects against regulated cell death in ovarian cells, potentially explaining the improved IVF outcomes observed.ConclusionsMelatonin supplementation significantly improved IVF outcomes in women of advanced maternal age, particularly those ≥ 38 years old, likely by modulating cuproptosis and ferroptosis and enhancing mitochondrial function in cumulus and granulosa cells. These results suggest that melatonin could be a promising adjuvant therapy for improving IVF success rates in older women.

Single-cell RNA sequencing reveals common interactions between follicle immune cells and granulosa cells in premature ovarian insufficiency patients.

To investigate the follicle microenvironment of individuals with premature ovarian insufficiency (POI), normal ovarian reserve (normal) and advanced maternal age (AMA), and identify potential therapeutic targets. A total of 9 women, including 3 POI, 3 normal and 3 AMA women, underwent in vitro fertilization or intracytoplasmic sperm injection were included in this study. For each participant, the first punctured follicle not containing cumulus cells were submitted to single-cell RNA sequencing to explore the characteristics of the follicle microenvironment of POI, normal and AMA individuals. A total of 87,323 cells were isolated and grouped into six clusters: T cells, B cells, neutrophils, basophils, mononuclear phagocytes, and granulosa cells. Further analysis demonstrated that the population of granulosa cells in cluster 6 was increased in AMA and POI patients, whereas the population of gamma delta T (GDT)-cells was decreased. We also found that the genes that were differentially expressed between GDT cells and monocytes were enriched in ribosome- and endoplasmic reticulum (ER)-related pathways. In addition, it showed that VEGFA-FLT1 interaction between the monocytes and granulosa cells may be lost in the AMA and POI patients as compared with the normal group. Loss of the VEGFA-FLT1 interaction in monocytes and granulosa cells, along with enriched ER- and ribosome-related pathways, may drive excess inflammation, accelerating granulosa cell senility and contributing to infertility. This study provides new insights into the pathogenesis of POI and aging and highlights the VEGFA/FLT1 interaction may be a potential therapeutic target for reducing inflammation and treating POI.

MiR-19b-3p inhibits cell viability and proliferation and promotes apoptosis by targeting IGF1 in KGN cells

Background Endometriosis (EM) is a major cause of infertility, but the pathogenesis and mechanisms are not yet fully elucidated. MiR-19b-3p is involved in many diseases, but its functional role in EM-associated infertility remains unexplored. This study aimed to examine miR-19b-3p abundance and IGF1 concentration in cumulus cells (CCs) and follicular fluid of EM-associated infertility patients, and to investigate the potential role of miR-19b-3p in KGN cells by identifying its target and elucidating the underlying mechanisms. Results The results from the case-control study indicated that, compared to the control group consisting of patients with tubal infertility, patients with EM-associated infertility exhibited a lower percentage of mature oocytes. MiR-19b-3p level was elevated in CCs from EM-associated infertility patients. IGF1 was identified as a direct target of miR-19b-3p and was negatively regulated by miR-19b-3p in KGN cells. Overexpression of miR-19b-3p significantly inhibited cell viability and proliferation, promoted apoptosis, and arrested the cell cycle at G0/G1 phase in KGN cells. The effects of miR-19b-3p were reversed by co-transfection of IGF1, and the biological effects of miR-19b-3p in KGN cells were mediated by IGF1. Additionally, miR-19b-3p targeted IGF1 to down-regulate AKT phosphorylation and participate in the apoptotic pathway in KGN cells. Conclusions This study demonstrates that miR-19b-3p level is elevated in CCs and IGF1 concentration is decreased in follicular fluid in patients with EM-associated infertility. MiR-19b-3p regulates the biological effects of KGN cells by targeting IGF1.

Phthalates are detected in the follicular fluid of adolescents and oocyte donors with associated changes in the cumulus cell transcriptome

ObjectiveTo investigate follicular fluid (FF) phthalate levels in adolescents undergoing fertility preservation compared to oocyte donors and explore its association with ovarian reserve and cumulus cell gene expression. DesignRetrospective study, and molecular analysis of cumulus cells (CCs) and FF SubjectsAdolescents (n= 20, 16.7 ± 0.6 years old) undergoing fertility preservation and oocyte donors (n= 24, 26.2 ± 0.4 years old). Main Outcome MeasuresPatient demographics, ovarian stimulation, and oocyte retrieval outcomes were analyzed for each group. FF levels of 9 phthalate metabolites were assessed individually and as molar sums representative of common compounds (all phthalates: ƩPhthalates; di(2-ethylhexyl) phthalate (DEHP) associated phthalate metabolites: ƩDEHP), exposure sources (plastics: ƩPlastic; personal care products: ƩPCP), and modes of action (anti-androgenic: ƩAA) and compared between the two groups. The transcriptome of CC associated with mature oocytes was compared between adolescents and oocyte donors using bulk RNA-sequencing. ResultsFollicular fluid ƩPlastic and ƩPCP levels were significantly higher in adolescents compared to oocyte donors (p<0.05). Follicular fluid ƩDEHP, ƩPlastic, ƩPCP, ƩAA, and ƩPhthalates levels were positively associated with antral follicle count (AFC) (p<0.05) in oocyte donors when adjusted for age, BMI, and race/ethnicity. RNA-seq analysis revealed 248 differentially expressed genes (DEGs) in cumulus cells of adolescents within the top quartile (n=4) of FF ƩPhthalates levels compared to the adolescents within the bottom half (n=9). Genes enriched in pathways involved in cell motility and development were significantly downregulated. ConclusionAdolescents undergoing fertility preservation cycles demonstrate higher levels of phthalate metabolites in their follicular fluid compared to oocyte donors. Phthalate metabolite levels in FF are associated with higher AFC levels in oocyte donors.

Feline cumulus cells and oocytes show massive accumulation of lipid droplets and upregulation of PLIN2 expression after in vitro maturation

This study investigates lipid content and expression of genes involved in lipid metabolism in feline cumulus cells and oocytes before and after in vitro maturation (IVM). Domestic cats represent valuable models in reproductive research, yet the efficiency of in vitro embryo production remains suboptimal, with contributing factors still under investigation. We characterized lipid droplets (LDs) in oocytes collected from adult queens, both before and after IVM, using confocal microscopy with Bodipy 493/503 staining. We also quantified the expression of four genes involved in regulation of lipid metabolism. Our findings revealed a substantial accumulation of LDs and a significant upregulation of PLIN2 expression in both cumulus cells and oocytes following IVM. The number and total area of LDs and fluorescence intensity increased markedly in oocytes at the MII stage, while the average LD diameter decreased. Similarly, cumulus cells showed an increase in number and total area of LDs post-IVM, suggesting their involvement in oocyte maturation by modulating lipid homeostasis. This study presents the first detailed characterization of lipid droplet dynamics in feline oocytes and cumulus cells, providing insights into metabolic processes during IVM, which are critical for optimizing assisted reproductive technologies in felids.

A method for determining potential parental contamination: linkage disequilibrium-based log-likelihood ratio analysis for IVF-PGT

BackgroundAt present, embryologists are attempting to use conventional in vitro fertilization (cIVF) as an alternative to intracytoplasmic sperm injection (ICSI) for preimplantation genetic testing (PGT). However, the potential parental contamination origin of sperm cells and cumulus cells is considered the main limiting factor in the inability of cIVF embryos to undergo PGT.MethodsIn this study, we established an IVF-PGTA assay for parental contamination tests with a contamination prediction model based on allele frequencies and linkage disequilibrium (LD) to compute the log-likelihood ratio (LLR) under competing ploidy hypotheses, and then verified its sensitivity and accuracy. Finally, comparisons of the effectiveness of SNP-based analysis and LLR-based IVF-PGTA among 40 cIVF embryos was performed, based on both statistical analysis of the parental contamination rate and chromosomal ploidy concordance rate between TE biopsy and ICM isolations.ResultsWith IVF-PGTA assay, biopsies with 10% maternal contamination could be detected accurately, and contamination caused by sperm cells could be eliminated completely. Utilizing LLR-based or single Nucleotide Polymorphism (SNP) -based analyses, our comprehensive examination of 40 clinically discarded fresh cIVF embryos revealed an absence of paternal contamination. Strikingly, the LLR-based analysis uniquely revealed a mere instance of 24% maternal contamination within the trophectoderm cell (TE) biopsy of 5* embryo. Furthermore, it was solely through this analysis that embryo (9-F) was identified as a triploid of paternal origin.ConclusionsIn this study, we developed a new bioinformatics analysis method for identifying parental contamination during IVF-PGT, especially for couples with nonmale factor infertility.

Effects of Ovarian Stimulation with Gonadotropins in the Conditions of Chronic Psychosocial Stress on the Quality of Murine Oocyte

Chronic psychosocial stress may negatively affect the female reproductive system. Meanwhile, the effect of ovarian stimulation with gonadotropins during stress on the quality of oocytes remains poorly studied. The purpose of this work was to investigate the effects of chronic psychosocial stress on the quality of murine cumulus-oocyte complexes during natural estrus cycle, as well as during ovarian stimulation with exogenous gonadotropins; the latter is an important part of modern assisted reproductive technologies. The results of the study demonstrate that psychosocial stress does not affect the number of ovulating oocytes, but worsens their quality, i. e. reduces the percentage of mature oocytes. In addition, stressed mice exhibited the increased accumulation of reactive oxygen species in oocytes, which is accompanied by the enhanced rate of apoptosis in cumulus cells. Hormonal stimulation of the ovaries with gonadotropins alleviates the negative changes associated with the psychosocial stress, normalizing the level of reactive oxygen species in oocytes and reducing the rate of apoptosis in cumulus cells.

Serum pentraxin-3 expression varies according to polycystic ovary syndrome phenotypes.

Pentraxin-3 (PTX-3) is a multibiological protein involved in cumulus cell expansion, fertilization, and implantation. This study was designed to analyze how circulating PTX-3 levels change in women with polycystic ovary syndrome (PCOS). A total of 50 Turkish participants, 35 of whom had PCOS and 15 of whom were fertile, were included in the study. Patients in the PCOS group were divided into 4 different phenotypes according to the NIH criteria (phenotypes A-D). The number of patients in phenotype A was the highest 13 (37.1%). In the calculations made without phenotyping, the serum ptx3 levels of the PCOS group were found to be significantly lower compared to the fertile control group (3.32 ± 0.73 ng/mL vs 4.97 ± 1.29 ng/mL; P < .001). The ptx3 value of phenotypes A and B was significantly lower than phenotype D (P = .008 and P = .009, respectively). When the phenotypes were compared with the fertile control group, the PTX-3 levels of phenotypes A and B were significantly lower than the fertile group. Although the ptx3 levels of phenotypes C and D were lower than the fertile group, the difference did not reach statistical significance. This is the first study to investigate serum ptx3 levels by phenotype in PCOS. While serum PTX-3 levels decreased in phenotypes A and B, ptx3 levels in phenotypes C and D were similar in fertile patients.

Ex vivo imaging reveals the spatiotemporal control of ovulation.

During ovulation, an egg is released from an ovarian follicle, ready for fertilization. Ovulation occurs inside the body, impeding direct studies of its progression. Therefore, the exact mechanisms that control ovulation have remained unclear. Here we devised live imaging methods to study the entire process of ovulation in isolated mouse ovarian follicles. We show that ovulation proceeds through three distinct phases, follicle expansion (I), contraction (II) and rupture (III), culminating in the release of the egg. Follicle expansion is driven by hyaluronic acid secretion and an osmotic gradient-directed fluid influx into the follicle. Then, smooth muscle cells in the outer follicle drive follicle contraction. Follicle rupture begins with stigma formation, followed by the exit of follicular fluid and cumulus cells and the rapid release of the egg. These results establish a mechanistic framework for ovulation, a process of fundamental importance for reproduction.

Seasonal environmental fluctuations alter the transcriptome dynamics of oocytes and granulosa cells in beef cows

BackgroundExamining the mechanistic cellular responses to heat stress could aid in addressing the increasing prevalence of decreased fertility due to elevated ambient temperatures. Here, we aimed to study the differential responses of oocytes and granulosa cells to thermal fluctuations due to seasonal differences. Dry beef cows (n = 10) were housed together, synchronized and subjected to a stimulation protocol to induce follicular growth before ovum pick-up (OPU). Two OPU’s were conducted (summer and winter) to collect cumulus-oocyte-complexes (COCs) and granulosa cells. In addition, rectal temperatures and circulating blood samples were collected during OPU. Oocytes were separated from the adherent cumulus cells, and granulosa cells were isolated from the collected OPU fluid. RNA was extracted from pools of oocytes and granulosa cells, followed by library preparation and RNA-sequencing. Blood samples were further processed for the isolation of plasma and leukocytes. The transcript abundance of HSP70 and HSP90 in leukocytes was evaluated using RT-qPCR, and plasma cortisol levels were evaluated by immunoassay. Environmental data were collected daily for three weeks before each OPU session. Data were analyzed using MIXED, Glimmix or GENMOD procedures of SAS, according to each variable distribution.ResultsAir temperatures (27.5 °C vs. 11.5 °C), average max air temperatures (33.7 °C vs. 16.9 °C), and temperature-humidity indexes, THI (79.16 vs. 53.39) were shown to contrast significantly comparing both the summer and winter seasons, respectively. Rectal temperatures (Summer: 39.2 ± 0.2 °C; Winter: 38.8 ± 0.2 °C) and leukocyte HSP70 transcript abundance (Summer: 4.18 ± 0.47 arbitrary units; Winter: 2.69 ± 0.66 arbitrary units) were shown to increase in the summer compared to the winter. No visual differences persisted in HSP90 transcript abundance in leukocytes and plasma cortisol concentrations during seasonal changes. Additionally, during the summer, 446 and 940 transcripts were up and downregulated in oocytes, while 1083 and 1126 transcripts were up and downregulated in the corresponding granulosa cells, respectively (Fold Change ≤ -2 or ≥ 2 and FDR ≤ 0.05). Downregulated transcripts in the oocytes were found to be involved in ECM-receptor interaction and focal adhesion pathways, while the upregulated transcripts were involved in protein digestion and absorption, ABC transporters, and oocyte meiosis pathways. Downregulated transcripts in the granulosa cells were shown to be involved in cell adhesion molecules, chemokine signaling, and cytokine-cytokine receptor interaction pathways, while those upregulated transcripts were involved in protein processing and metabolic pathways.ConclusionIn conclusion, seasonal changes dramatically alter the gene expression profiles of oocytes and granulosa cells in beef cows, which may in part explain the seasonal discrepancies in pregnancy success rates during diverging climatic weather conditions.

PRP Influences Maturation and Fertilisation of Immature Mouse Oocytes.

In vitro maturation (IVM) of immature oocytes is a valuable method to enhance the rate of mature oocytes available for fertilisation. In the current study, platelet-rich plasma (PRP) was employed in IVM medium of immature oocytes. Harvested germinal vesicle stage oocytes with cumulus cells from female mature BALB/c mice divided into two groups of control and experiment. In the experimental group, GV oocytes matured in the IVM medium supplemented with 5% PRP, while in the control group, GV oocytes matured in the IVM medium without PRP. The percentage of GV, MI, MII and degenerated oocytes, zona pellucida thickness, perivitelline space size, diameter of mature oocytes, gene expression of apoptosis-related factors and subsequent development of matured oocytes were assessed. The PRP group displayed significantly improved outcomes in various parameters, including a higher proportion of MII and fertilised oocytes, cleavage and blastocyst embryos, compared to the control group. Moreover, the thickness of the zona pellucida was significantly lower in the PRP group than in the control group (p < 0.05). Furthermore, the PRP group demonstrated a significant decrease in the expression of transcripts associated with apoptosis (Bax and caspase-3); however, in the PRP group, a substantial increase in the expression of Bcl2l1, an apoptosis inhibitor, was observed when compared to the control group (p < 0.05). In conclusion, addition of PRP to the IVM culture media significantly increased oocyte maturation rate, leading to improved fertilisation and subsequent embryonic development. This enhancement highlights the positive influence of PRP on overall invitro maturation efficiency and early embryonic stages.

Multi-omics approach to reveal follicular metabolic changes and their effects on oocyte competence in PCOS patients.

Polycystic ovary syndrome (PCOS) is a common heterogeneous disorder linked with endocrine and metabolic disturbances. The underlying mechanism of PCOS, especially its effect on oocyte competence, remains unclear. The study aimed to identify abnormal follicular metabolic changes using a multi-omics approach in follicular fluid from PCOS patients and to determine their effects on oocyte competence. A total of 36 women with PCOS and 35 women without PCOS who underwent in vitro fertilization and embryo transfer were included in the study. Cumulus cells and follicular fluid samples were collected. Follicular fluid samples underwent metabolomic analysis, while cumulus cell clusters from the same patients were assessed using transcriptomic analysis. Clinical information of patients and assisted reproductive technology (ART) results were recorded. Transcriptomics and metabolomics were integrated to identify disrupted pathways, and receiver operation characteristics (ROC) analysis was conducted to identify potential diagnostic biomarkers for PCOS. Pearson correlation analysis was conducted to assess the relationship between metabolites in follicular fluid and oocyte competence (fertilization and early embryo development potential). Through multi-omics analysis, we identified aberrantly expressed pathways at both transcriptional and metabolic levels, such as the citrate cycle (TCA cycle), oxidative phosphorylation, the cAMP signaling pathway, the mTOR signaling pathway, and steroid hormone biosynthesis. Ten candidate metabolites were identified based on metabolic profiling data from these altered pathways. Phytic acid, succinic acid, 2'-deoxyinosine triphosphate, and 4-trimethylammoniobutanoic acid in the follicular fluid exhibited high specificity and sensitivity in distinguishing PCOS. Among these metabolites, L-arginine showed a negative correlation with the 2PN fertilization rate and cleavage rate, while estrone sulfate showed a negative correlation with the high-quality embryo rate in the in-vitro fertilization (IVF) cycle. We have conducted a preliminary study of a novel metabolic signature in women with PCOS using a multi-omics approach. The alterations in key metabolic pathways may enhance our understanding of the pathogenesis of PCOS.

The possible regulatory role of miR-4463 and its target gene CYP19A1 on the ovarian response in the women with diminished ovarian reserve: A case-control study.

Diminished ovarian reserve (DOR) is a condition that affects fertility by reducing the reproductive potential of the ovary. The altered expression profile of cumulus cells (CCs) can negatively affect the quality and quantity of oocytes in the ovaries. Recent studies suggest that circulating miRNAs play a significant role in the ovary function, and their serum expression changes can be valuable biomarkers for predicting ovarian function. Investigating the expression levels of circulating miRNA-4463 and its target cytochrome P450 19A1 gene (CYP19A1) in DOR-CCs in order to find a molecular pathway involved in DOR. In this case-control study, a total of 20 DOR-women and 20 women with normal ovarian reservation aged between 20-34 yr referred to Yazd Reproductive Science Institute, Yazd, Iran were included in the study. Serum and CCs were collected, and real time-polymerase chain reaction was performed to investigate the expression level of miR-4463, and its target gene CYP19A1. Our results showed an inverse relationship between miR-4463 and CYP19A1 expression levels. Therefore, the increase in the expression of miR-4463 was significantly evident in DOR-women compared to the control group (p = 0.0019), while the expression of its target gene, CYP19A1, has significantly decreased in these women (p = 0.001). The present study suggests that miR-4463 and CYP19A1 pathways could regulate ovary function. Therefore, examination of this miRNA could be a promising parameter for predicting ovarian reserve and their response to stimulation protocols.

Gene expression levels in cumulus cells are correlated with developmental competence of bovine oocytes

The generation of mammalian embryos by in vitro culture is hampered by the failure of many of the embryos to develop to the blastocyst stage. This problem occurs even when cumulus–oocyte complexes (COCs) with good morphology are visually selected and used for culture. Because cumulus cells are important for oocyte maturation and subsequent embryo development, here we compared gene expression patterns in cumulus cells of COCs that developed in vitro to the blastocyst stage with those of COCs that failed to develop. Cumulus cells were aspirated from bovine COCs selected for in vitro culture. Oocyte developmental competence was evaluated by screening for cleavage and development to the blastocyst stage. The collected cumulus cells were used to quantify mRNA levels of FSH receptor (FSHR), insulin-like growth factor-1 receptor (IGF-1R), anti-Müllerian hormone (AMH), AMH receptor II (AMHRII), epidermal growth factor receptor (EGFR), estrogen receptor β (ERβ), B cell lymphoma/leukemia-2 associated X (Bax), and cysteine-aspartic acid protease-3 (Caspase-3). We found that the expression levels of FSHR, IGF-1R, AMH, and EGFR were higher in cumulus cells from COCs that developed to blastocysts as compared with those that failed to develop, whereas expression levels of Bax and Caspase-3 were lower in cumulus cells of COCs that matured to the blastocyst stage. Positive correlations were found between FSHR and IGF-1R expression (r = 0.59) and between ERβ and EGFR expression (r = 0.43) in cumulus cells from COCs that developed to the blastocyst stage. Our findings indicate that gene expression levels in cumulus cells are correlated with the developmental competence of bovine oocytes. Measurement of gene expression in cumulus cells therefore offers a non-invasive means of predicting oocyte developmental competence.

The dose-dependent dual effects of alpha-ketoglutarate (AKG) on cumulus oocyte complexes during in vitro maturation

In this study, we reported for the first time the dose-dependent dual effects of Alpha-Ketoglutarate (AKG) on cumulus oocyte complexes (COCs) during in vitro maturation (IVM). AKG at appropriate concentration (30 µM) has beneficial effects on IVM. This includes improved cumulus expansion, oocyte quality, and embryo development. These effects are mediated through multiple underlying mechanisms. AKG reduced the excessive accumulation of reactive oxygen species (ROS) in cumulus cells, reduced the consumption of GSH and NADPH. Cumulus GSH and NADPH were transported to oocytes via gap junctions, thereby reducing the oxidative stress, apoptosis and maintaining the redox balance in oocytes. In addition, AKG improved the mitochondrial function by regulating the mitochondrial complex 1 related gene expression in oocytes to maintain mitochondrial membrane potential and ATP production. On the other hand, oocyte generated GDF9 could also be transported to cumulus cells to promote cumulus expansion. Conversely, a high concentration of AKG (750 µM) exerted adverse effects on IVM and suppressed the cumulus expansion as well as reduced the oocyte quality. The suppression of the cumulus expansion caused by high concentration of AKG could be rescued with GDF9 supplementation in COCs, indicating the critical role of GDF9 in IVM. The results provide valuable information on the variable effects of AKG at different concentrations on reproductive physiology.Graphical abstract

NPR3 is regulated by gonadotropins and modulates bovine cumulus cell expansion.

The significant role of C-type natriuretic peptide (CNP) and its receptor 2 (NPR2) in regulating oocyte meiotic maturation and facilitating communication between oocytes and surrounding cumulus cells has been well-documented in various mammalian species, including mice, cattle and swine. However, further investigation is needed to ascertain whether natriuretic peptide receptors (NPRs) are involved in regulating other essential ovarian functions. Hence, this study aimed to explore the potential involvement of NPRs in the regulation of cumulus expansion and oocyte meiotic maturation in bovine cumulus-oocyte complexes (COCs). The findings revealed that NPR3 mRNA abundance was downregulated by FSH and LH in cumulus cells of bovine COCs during in vitro maturation (IVM), while NPR2 mRNA levels were not affected by gonadotropins. Inhibition of the epidermal growth factor receptor (EGFR) during IVM of COCs prevented the NPR3 mRNA downregulation induced by gonadotropins in cumulus cells. Additionally, treatment of COCs during IVM with an NPR3 agonist (cANP4-23) inhibited cumulus expansion induced by gonadotropins. This inhibitory effect was further intensified when COCs were co-treated with cANP4-23 and CNP. These findings provide robust evidence indicating that normal cumulus expansion in bovine COCs involves an inhibitory effect of gonadotropins on NPR3 mRNA expression, which is mediated via EGFR signaling. The study also provides evidence that CNP and NPR3 interact synergistically to regulate cumulus expansion in response to gonadotropins.