Multi-Omics Reveal the Metabolic Changes in Cumulus Cells During Aging.

Maternal age has been reported to impair oocyte quality. However, the molecular mechanisms underlying the age-related decrease in oocyte competence remain poorly understood. Cumulus cells establish direct contact with the oocyte through gap junctions, facilitating the provision of crucial nutrients necessary for oocyte development. In this study, we obtained the proteomic and metabolomic profiles of cumulus cells from both young and old mice. We found that fatty acid beta-oxidation and nucleotide metabolism, markedly active in aged cumulus cells, may serve as a compensatory mechanism for energy provision. Tryptophan undergoes two principal metabolic pathways, including the serotonin (5-HT) synthesis and kynurenine catabolism. Notably, we discovered that kynurenine catabolism is reduced in aged cumulus cells compared to young cells, whereas 5-HT synthesis exhibited a significant decrease. Furthermore, the supplement of 5-HT during cumulus-oocyte complexes (COCs) culture significantly ameliorated the metabolic dysfunction and meiotic defects in old oocytes. In sum, our data provide a comprehensive multiple omics resource, offering potential insights for improving oocyte quality and promoting fertility in aged females.