Mixed probiotics modulated gut microbiota to improve spermatogenesis in bisphenol A-exposed male mice.

Bisphenol A (BPA), an environmental endocrine disruptor (EDC), has been implicated in impairing intestinal and male reproductive dysfunction. The efficacy of gut microbiota modulation for BPA-exposed testicular dysfunction has yet to be verified through research. Therefore, this study explored the potential of mixed probiotics in restoring spermatogenesis damage through the gut-testis axis under BPA exposure. We selected two probiotics strains (Lactobacillus rhamnosus and Lactobacillus plantarum) with BPA removal properties in vitro and the BPA-exposed male mice model was established. The probiotics mixture effectively reduced BPA residue in the gut, serum, and testis in mice. Through 16 S rDNA-seq and metabolomics sequencing, we uncovered that vitamin D metabolism and bile acid levels in the gut was abolished under BPA exposure. This perturbation was linked to an increased abundance of Faecalibaculum and decreased abundance of Lachnospiraceae_NK4A136_group and Ligilactobacillus. The probiotics mixture restored this balance, enhancing intestinal barrier function and reducing oxidative stress. This improvement was accompanied by a restored balance of short-chain fatty acids (SCFAs). Remarkably, the probiotics ameliorated testicular dysfunction by repairing structures of seminiferous tubules and reversing arrested spermiogenesis. Further, the probiotics mixture enhanced testosterone-driven increases in spermatogonial stem cells and all stages of sperm cells. Testicular transcriptome profiling linked these improvements to fatty acid degradation and peroxisome pathways. These findings suggest a significant interplay between spermatogenesis and gut microbiota, demonstrating that probiotic intake could be a viable strategy for combating male subfertility issues caused by BPA exposure.

Effect of PFOA exposure on diminished ovarian reserve and its metabolism.

Owing to its difficulty in degrading and ease of accumulation in the body, perfluorooctanoic acid (PFOA) has a detrimental effect on reproduction. This study aimed to examine the effect of PFOA concentration in follicular fluid during ovulation stimulation on embryo quality and the impact of PFOA exposure on the metabolic components of follicular fluid. This was a single-center prospective study that included 25 patients with diminished ovarian reserve (DOR), 25 with normal ovarian reserve (NOR), and 25 with polycystic ovary syndrome (PCOS). Follicular fluid samples were analyzed using ultra-high performance liquid chromatography-tandem mass spectrometry. We demonstrated that the PFOA levels of follicular fluid in the DOR group were higher than those in the NOR group and PCOS group (P < 0.05). PFOA concentration in the PCOS group was negatively correlated with high-quality embryos (P < 0.05). To gain more insight into the impact of PFOA on the metabolic composition of follicular fluid, we classified the DOR group based on the PFOA concentration, for which metabolomic analysis was performed. In the high-concentration PFOA group, there was an increase and a decrease in three and nine metabolites, respectively, compared to that in the low-concentration group. These results suggest that PFOA may alter the metabolic composition of follicular fluid, thus, affecting ovarian reserve function.

Telomere Dysfunction in Oocytes and Embryos From Obese Mice.

Maternal obesity impairs oocyte quality and embryo development. However, the potential molecular pathways remain to be explored. In the present study, we examined the effects of obesity on telomere status in oocytes and embryos obtained from mice fed with high-fat diet (HFD). Of note, telomere shortening was observed in both oocytes and early embryos from obese mice, as evidenced by the reduced expression of telomerase reverse transcriptase and activity of telomerase. Moreover, quantitative analysis of telomere dysfunction-induced foci (TIFs) revealed that maternal obesity induces the defective telomeres in oocytes and embryos. Meanwhile, the high frequency of aneuploidy was detected in HFD oocytes and embryos as compared to controls, accompanying with the increased incidence of apoptotic blastocysts. In conclusion, these results indicate that telomere dysfunction might be a molecular pathway mediating the effects of maternal obesity on oocyte quality and embryo development.

FKBP25 Regulates Meiotic Apparatus During Mouse Oocyte Maturation.

FK506 binding proteins 25 (FKBP25) has been shown to function in ribosome biogenesis, chromatin organization, and microtubule stability in mitosis. However, the role of FKBP25 in oocyte maturation has not been investigated. Here, we report that oocytes with FKBP25 depletion display abnormal spindle assembly and chromosomes alignment, with defective kinetochore-microtubule attachment. Consistent with this finding, aneuploidy incidence is also elevated in oocytes depleted of FKBP25. Importantly, FKBP25 protein level in old oocytes is significantly reduced, and ectopic expression of FKBP25 could partly rescue the aging-associated meiotic defects. In addition, by employing site-specific mutagenesis, we identify that serine 163 is a major, if not unique, phosphorylation site modulating the action of FKBP25 on meiotic maturation. In summary, our data indicate that FKBP25 is a pivotal factor for determining oocyte quality, and may mediate the effects of maternal aging on female reproduction.

Involvement of SIRT3-GSK3ß deacetylation pathway in the effects of maternal diabetes on oocyte meiosis.

OBJECTIVES: It has been widely reported that maternal diabetes impairs oocyte quality. However, the responsible mechanisms remain to be explored. In the present study, we focused on whether SIRT3-GSK3ß pathway mediates the meiotic defects in oocytes from diabetic mice. MATERIALS AND METHODS: GSK3ß functions in mouse oocyte meiosis were first detected by targeted siRNA knockdown. Spindle assembly and chromosome alignment were visualized by immunostaining and analysed under the confocal microscope. PCR-based site mutation of specific GSK3ß lysine residues was used to confirm which lysine residues function in oocyte meiosis. siRNA knockdown coupled with cRNA overexpression was performed to detect SIRT3-GSK3ß pathway functions in oocyte meiosis. Immunofluorescence was performed to detect ROS levels. T1DM mouse models were induced by a single intraperitoneal injection of streptozotocin. RESULTS: In the present study, we found that specific depletion of GSK3ß disrupts maturational progression and meiotic apparatus in mouse oocytes. By constructing site-specific mutants, we further revealed that acetylation state of lysine (K) 15 on GSK3ß is essential for spindle assembly and chromosome alignment during oocyte meiosis. Moreover, non-acetylation-mimetic mutant GSK3ß-K15R is capable of partly preventing the spindle/chromosome anomalies in oocytes with SIRT3 knockdown. A significant reduction in SIRT3 protein was detected in oocytes from diabetic mice. Of note, forced expression of GSK3ß-K15R ameliorates maternal diabetes-associated meiotic defects in mouse oocytes, with no evident effects on oxidative stress. CONCLUSION: Our data identify GSK3ß as a cytoskeletal regulator that is required for the assembly of meiotic apparatus, and discover a beneficial effect of SIRT3-dependent GSK3ß deacetylation on oocyte quality from diabetic mice.

Melatonin ameliorates the advanced maternal age-associated meiotic defects in oocytes through the SIRT2-dependent H4K16 deacetylation pathway.

It has been widely reported that advanced maternal age impairs oocyte quality. To date, various molecules have been discovered to be involved in this process. However, prevention of fertility issues associated with maternal age is still a challenge. In the present study, we find that both in vitro supplement and in vivo administration of melatonin are capable of alleviating the meiotic phenotypes of aged oocytes, specifically the spindle/chromosome disorganization and aneuploidy generation. Furthermore, we identify SIRT2 as a critical effector mediating the effects of melatonin on meiotic structure in old oocytes. Candidate screening shows that SIRT2-controlled deacetylation of histone H4K16 is essential for maintaining the meiotic apparatus in oocytes. Importantly, non-acetylatable-mimetic mutant H4K16R partially rescues the meiotic deficits in oocytes from reproductive aged mice. In contrast, overexpression of acetylation-mimetic mutant H4K16Q abolishes the beneficial effects of melatonin on the meiotic phenotypes in aged oocytes. To sum up, our data uncover that melatonin alleviates advanced maternal aged-associated meiotic defects in oocytes through the SIRT2-depenendet H4K16 deacetylation pathway.