Search

Objective: To reveal the relationship between mitochondrial function in cumulus cells (CCs) and the aging-related decline in ovarian function and reproductive capacity., Design: Retrospective and transcriptome analysis of human tissue., Setting: University hospital., Patient(s): A total of 186 infertile women with normal weight and no other diseases, including 86 young women (aged <38 years) with normal ovarian reserve and 100 advanced-age women (aged ≥38 years) with diminished ovarian reserve., Intervention(s): None., Main Outcome Measure(s): Embryo development data were analyzed. The mitochondrial ultrastructure of CCs was observed by transmission electron microscopy. Mitochondrial activity was detected by immunofluorescence. The per-CC mitochondrial deoxyribonucleic acid copy numbers and cellular adenosine triphosphate levels were quantified. Unbiased comprehensive genome-wide transcriptomics was performed. The functions of all annotated genes and biologic pathways were analyzed by the Kyoto Encyclopedia of Genes and Genomes., Result(s): Advanced-age women with diminished ovarian function had significantly fewer retrieved oocytes and lower embryo quality. The normal mitochondrial rate in CCs was significantly lower. In addition to mitochondrial morphology and structural changes, the fluorescence intensity of Fluo-3/AM was significantly higher, and that of MitoTracker was lower than that of young women with normal ovarian reserve, suggesting that age negatively affects the mitochondrial activity of CCs. The per-CC mitochondrial deoxyribonucleic acid copy number and adenosine triphosphate levels significantly decreased in the advanced-age group. The Kyoto Encyclopedia of Genes and Genomes analysis showed that differentially expressed genes were significantly enriched in the oxidative phosphorylation pathway. Additionally, most mitochondrially encoded genes related to oxidative phosphorylation were significantly down-regulated in the advanced-age group., Conclusion(s): We present current evidence that mitochondrial dysfunction in CCs may play a key role in the age-related decline in ovarian function and reproductive capacity., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To determine aberrant circular RNA (circRNA) expression profiles in cumulus cells from polycystic ovarian syndrome (PCOS) patients and identify their potential biological functions., Design: Circular RNAs microarray analysis of human tissue., Setting: University hospital., Patient(s): A total of 40 women, including 20 PCOS patients and 20 non-PCOS patients., Intervention(s): None., Main Outcome Measure(s): A circRNA microarray containing probes that interrogate 21,442 human circRNAs to investigate differentially expressed circRNAs in cumulus cells, with potential target genes of significantly changed circRNAs and biological functions measured by microRNA support vector regression (mirSVR) and gene ontology (GO) analysis, with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis., Result(s): A total of 1,032 circRNAs were identified that were differentially expressed in PCOS cumulus cells, including 311 circRNAs increase and 721 circRNAs decrease (fold change ≥2). Four aberrantly expressed circRNAs reached a statistically significant result after Bonferroni correction (with Bonferroni correction, only circRNAs for which P < .05/21,442 = 2.3 × 10 -6 were considered statistically significant). Further analysis showed that aberrantly expressed circRNAs harbored microRNA binding sites, and some microRNAs were associated with PCOS. The GO and KEGG biological pathway analysis indicated that the genes with protein binding, mitotic nuclear envelope disassembly and metabolic pathways were statistically significantly enriched., Conclusion(s): Our data suggest that the aberrantly expressed circRNAs and their targeted genes might be associated with PCOS, providing new clues to find key diagnostic and therapeutic molecular biomarkers for PCOS patients., (Copyright © 2019 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age, and oocyte developmental competence is altered in patients with PCOS. In recent years microRNAs (miRNAs) have emerged as important regulators of gene expression, the aim of the study was to study miRNAs expression patterns of cumulus cells from PCOS patients., Methods: The study included 20 patients undergoing in vitro fertilization (IVF) and intra-cytoplasmic sperm injection (ICSI): 10 diagnosed with PCOS and 10 matching controls. We used deep sequencing technology to identify the miRNAs differentially expressed in the cumulus cells of PCOS., Results: There were 17 differentially expressed miRNAs in PCOS cumulus cells, including 10 miRNAs increase and 7 miRNAs decrease. These miRNAs were predicted to target a large set of genes with different functions, including Wnt- and MAPK- signaling pathways, oocyte meiosis, progesterone-mediated oocyte maturation and cell cycle. Unsupervised hierarchical clustering analysis demonstrated that there was a specific miRNAs expression pattern in PCOS cumulus cells., Conclusion: We found that the miRNAs expression profile was different in cumulus cells isolated from PCOS patients compared with control. This study provided new evidence for understanding the pathogenesis of PCOS.

STUDY QUESTION What are the differences in gene expression of cumulus cells (CCs) between young women with diminished ovarian reserve (DOR) and those of similar age with normal ovarian reserve (NOR)? SUMMARY ANSWER Gene expression and metabolome profiling analysis demonstrate that the de novo serine synthesis pathway (SSP) is increased in the CCs of young women with DOR. WHAT IS KNOWN ALREADY The incidence of DOR has risen, tending to present at younger ages. Its mechanisms and aetiologies are still poorly understood. Abnormal metabolism is present in luteinized CCs of patients with DOR. Previous studies have revealed that mitochondrial dysfunction and impaired oxidative phosphorylation in CCs are related to DOR in women of advanced age. The pathogenic mechanisms likely differ between young women with DOR and cases associated with advanced maternal age. Several studies have examined amino acid metabolism in the follicle, with a focus on embryo development, but less information is available about CCs. The physiological significance of de novo serine synthesis in follicles and oocytes remains largely unknown. STUDY DESIGN, SIZE, DURATION CC samples were obtained from 107 young infertile women (age <38 years) undergoing ICSI, from July 2017 to June 2019, including 54 patients with DOR and 53 patients with NOR. PARTICIPANTS/MATERIALS, SETTING, METHODS Oocyte development data were analysed retrospectively. Comprehensive genome-wide transcriptomics of CCs was performed. Differentially expressed genes (DEGs) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to categorize the functions of the DEGs and identify significantly enriched pathways. The transcript and protein levels of key enzymes involved in serine synthesis were verified in additional samples using quantitative real-time PCR (qRT-PCR) (n = 10) and capillary western blotting (n = 36). Targeted metabolomics of amino acids in CC extracts was performed by ultrahigh-performance liquid MS (UHPLC–MS/MS). MAIN RESULTS AND THE ROLE OF CHANCE The number of oocytes (2.4 ± 2.2 versus 12.1 ± 5.3) and metaphase II oocytes (2.1 ± 2.0 versus 9.9 ± 4.9) retrieved was significantly decreased in the DOR versus the NOR group, respectively (P  <   0.0001). The rates of fertilization (80.7% versus 78.8%), viable embryos (73.7% versus 72.5%), and high-quality embryos (42.8% versus 49.0%) did not differ between the DOR and NOR groups, respectively (P  >   0.05). A total of 95 DEGs were found by transcriptome sequencing. GO and KEGG analyses demonstrated that the DEGs were linked to amino acid metabolism and suggested significantly higher activity of the de novo SSP in the CCs of young women with DOR. Further qRT-PCR and capillary western blotting revealed that key enzymes (PHGDH, PSAT1, PSPH, and SHMT2) involved in de novo serine synthesis were upregulated, and UHPLC–MS/MS analysis showed increases in serine and glycine (a downstream product of serine) levels in the CCs of young patients with DOR. Our data clearly demonstrate that the de novo SSP, which diverts 3-phosphoglycerate from glycolysis to serine synthesis, was upregulated in young DOR CCs. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION Regarding the reproductive capacity of young patients DOR, the pregnancy outcomes were not analysed. The sample size was limited, and only women undergoing ICSI were examined since this was a prerequisite for the acquisition of CCs, which may cause selection bias. The exact mechanisms by which the SSP in CCs regulates ovarian reserve still require further study. WIDER IMPLICATIONS OF THE FINDINGS Our research presents new evidence that alterations of the SSP in CCs of young infertile women are associated with DOR. We believe this is a significant contribution to the field, which should be key for understanding the cause and mechanisms of ovarian hypofunction in young women. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by grants from the Ministry of Science and Technology of China (2018YFC1005001) and National Natural Science Foundation of China (31601197). There were no competing interests. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]