Integrated transcriptomics and proteomics assay identifies the role of FCGR1A in maintaining sperm fertilization capacity during semen cryopreservation in sheep

Integrated analyses of transcriptomes, metabolomes, and proteomes unveil the role of FoXO signaling axis in buck semen cryopreservation

Sperm cryopreservation is a complex process involving gene expression, protein synthesis, membrane stability, and metabolic adaptation. However, molecular alterations in sperm cryopreservation and the mechanisms defending against freezing damage remain poorly understood. This study investigates these changes and defense mechanisms using transcriptomics, proteomics, and metabolomics data. During sperm cryopreservation, the expression level of G protein subunit alpha i3 (GNAI3) was significantly downregulated in post-thaw sperm (P < 0.001), while matrix metallopeptidase 9 (MMP9) was upregulated compared to FS groups (P < 0.01). Additionally, interleukin 6 (IL6) expression in the CS group showed an approximate increase (P < 0.05), whereas ribosomal protein S27a (RPS27A) expression decreased markedly (P < 0.05). Other important molecules such as macrophage stimulating 1 receptor (MST1R), hypoxia-inducible factor 1 subunit alpha (HIF1A), fibroblast growth factor 8 (FGF8), CD9 molecule (CD9), peptidase D (PEPD) and terminal nucleotidyltransferase 5B (TENT5B) also exhibited significant changes in expression (P < 0.05). Moreover, the study revealed the regulatory roles of metabolites such as glucose and glutamic acid during sperm cryopreservation. The involvement of catalase (CAT) protein in antioxidant defense was also noted. The interactions among mRNAs, miRNAs, proteins, and metabolites highlight the critical role of the FoxO signaling pathway in modulating responses to freezing. Our study reveals the molecular regulatory mechanisms of sperm during cryopreservation, emphasizing the importance of the FoxO pathway and specific metabolites in response to cryo-injury. These findings provide deeper insights into the complexity of sperm cryobiology and offer practical guidance for optimizing sperm cryopreservation.

Proteomics and metabolomics analyses of mechanism underlying bovine sperm cryoinjury

BACKGROUND

The cryoinjury of semen during cryopreservation reduces sperm motility, constraining the application of artificial insemination (AI) in bovine reproduction. Some fertility markers, related to sperm motility before and after freezing have been identified. However, little is known about the biological mechanism through which freezing reduces sperm motility. This study investigated the selective effects of cryoinjury on high-motility sperm (HMS) and low-motility sperm (LMS) in frozen-thawed from the perspectives of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and ATP levels. The molecular mechanism of decreased sperm motility caused by cryoinjury was explored through a joint analysis of 4D-label free quantitative proteomics and non-targeted metabolomics.

RESULTS

The results indicate that low levels of ROS and high degrees of MMP and ATP play a critical role in the survival of HMS during the freezing process. The sperm samples from the frozen-thawed HMS and LMS were analysed for proteomics and metabolomics, 2,465 proteins and 4,135 metabolites were detected in bovine sperm samples. In contrast to LMS, HMS have 106 proteins and 106 metabolites with high abundance expression, and 79 proteins and 223 metabolites with low abundance expression. Proteomics and metabolomics data exhibit that highly expressed antioxidant enzymes and metabolites in HMS can maintain sperm motility by regulating the ROS produced during freezing to prevent sperm from oxidative stress and apoptosis. Furthermore, the KEGG analysis of differential proteins and metabolites during the freezing process implies that the significant enrichment of glycolysis and cAMP in HMS can guarantee energy supply.

CONCLUSIONS

The results provided that during the process of bovine sperm freezing, highly expressed antioxidant enzymes can regulate the reactive oxygen species levels to avoid oxidative stress and the glycolysis signalling pathway ensures ATP production can sustain frozen-thawed sperm motility.

The beneficial effects of quinoa seed extract supplementation on ram sperm quality following cryopreservation

Although cryopreservation is a reliable method used in assisted reproduction to preserve genetic materials, it can stimulate the occurrence of oxidative stress, which affects sperm structure and function. This research was conducted to explore the effects of quinoa seed extracts (QSE) on ram sperm quality, oxidative biomarkers, and the gene expression of frozen-thawed ram sperm. Semen samples were diluted in extenders supplemented with 0 (QSE0), 250 (QSE1), 500 (QSE2), 750 (QSE3), and 1000 (QSE4) µg of QSE /mL, and then frozen according to the typical procedure. The findings indicate that the QSE3 and QSE4 groups provided the optimal results in terms of sperm viability and progressive motility. Sperm kinematics were considerably enhanced in the QSE3 group compared to the other groups (P<0.01). QSE (500-1000 µg/mL) significantly decreased the apoptosis-like changes (higher viable and lower apoptotic sperm) in ram sperm (P<0.001). The percentage of live sperm with intact acrosomes was significantly increased, while the percentage of detached and intact acrosomes in live and dead sperm were significantly decreased respectively by the QSE addition (P<0.001). All QSE groups had higher TAC and lower MDA and H2O2 levels than the control group (P<0.001). The expressions of SOD1, CAT, GABPB1, and GPX1 genes in sperm samples were significantly increased, while the CASP3 gene was significantly decreased in all QSE-supplemented samples. Our data suggest that QSE has beneficial effects on sperm quality of cryopreserved ram semen, which are achieved by promoting sperm antioxidant-related genes and reducing apoptosis-related gene.