Proteomic analysis and in vivo visualization of extracellular vesicles from mouse oviducts during pre-implantation embryo development.

Pre-implantation embryonic development occurs in the oviduct during the first few days of pregnancy. The presence of oviductal extracellular vesicles (oEVs, also called oviductosomes) is crucial for pre-implantation embryonic development in vivo as oEVs often contain molecular transmitters such as proteins. Therefore, evaluating oEV cargo during early pregnancy could provide insights into factors required for proper early embryonic development that are missing in the current in vitro embryo culture setting. In this study, we isolated oEVs from the oviductal fluid at estrus and different stages of early embryonic development. The 2306-3066 proteins in oEVs identified at the different time points revealed 58-60 common EV markers identified in exosome databases. Oviductal extracellular vesicle proteins from pregnant samples significantly differed from those in non-pregnant samples. In addition, superovulation changes the protein contents in oEVs compared to natural ovulation at estrus. Importantly, we have identified that embryo-protectant proteins such as high-mobility protein group B1 and serine (or cysteine) peptidase inhibitor were only enriched in the presence of embryos. We also visualized the physical interaction of EVs and the zona pellucida of 4- to 8-cell stage embryos using transmission electron microscopy as well as in vivo live imaging of epithelial cell-derived GFP-tagged CD9 mouse model. All protein data in this study are readily available to the scientific community in a searchable format at https://genes.winuthayanon.com/winuthayanon/oviduct_ev_proteins/. In conclusion, we identified oEVs proteins that could be tested to determine whether they can improve embryonic developmental outcomes in vivo and in vitro setting.

Serine protease inhibitor disrupts sperm motility leading to reduced fertility in female mice†.

Inhibition of the sperm transport process in the female reproductive tract could lead to infertility. We previously showed that a pan-serine protease inhibitor, 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF), blocked semen liquefaction in vivo and resulted in a drastic decrease in the number of sperm in the oviduct of female mice. In this study, we used a mouse model to test the efficacy of AEBSF as a reversible contraceptive, a sperm motility inhibitor, and a spermicide. Additionally, this study evaluated the toxicity of AEBSF on mouse vaginal tissues in vivo and human endocervical cells in vitro. We found that female mice treated with AEBSF had significantly less pups born per litter as well as fertilization rates in vivo compared to the vehicle control. We then showed that AEBSF reduced sperm motility and fertilization capability in vitro in a dose-dependent manner. Furthermore, AEBSF also exhibited spermicidal effects. Lastly, AEBSF treatment in female mice for 10 min or 3 consecutive days did not alter vaginal cell viability in vivo, similar to that of the vehicle and non-treated controls. However, AEBSF decreased cell viability of human ectocervical (ECT) cell line in vitro, suggesting that cells in the lower reproductive tract in mice and humans responded differently to AEBSF. In summary, our study showed that AEBSF can be used as a prototype compound for the further development of novel non-hormonal contraceptives for women by targeting sperm transport in the female reproductive tract.

Deletion of Kallikrein-related peptidases ( Klks ) has no effect on fertility in mice.

Kallikreins (KLKs) are serine peptidases. It was established that Klks are estrogen-target genes in mouse uteri. However, the functional requirement of KLK family in the uterine function during reproduction is unknown. Here we generated a compound deletion of Klk1b3, Klk1b4, Klk1b5, and Klk1 in a mouse model using CRISPR/Cas9 strategy with four single guide RNAs (sgRNAs) to target the second exon of these four genes that are aligned back-to-back in a single locus spanning 32.95 kb on chromosome 7. We found that both male and female knockout mice are fertile with no apparent health defect compared to wild-type controls. Our data suggest that Klk1b3, Klk1b4, Klk1b5, and Klk1 are not necessary for male and female reproductive function in mice.

Multi-omics analyses and machine learning prediction of oviductal responses in the presence of gametes and embryos.

The oviduct is the site of fertilization and preimplantation embryo development in mammals. Evidence suggests that gametes alter oviductal gene expression. To delineate the adaptive interactions between the oviduct and gamete/embryo, we performed a multi-omics characterization of oviductal tissues utilizing bulk RNA-sequencing (RNA-seq), single-cell RNA-sequencing (scRNA-seq), and proteomics collected from distal and proximal at various stages after mating in mice. We observed robust region-specific transcriptional signatures. Specifically, the presence of sperm induces genes involved in pro-inflammatory responses in the proximal region at 0.5 days post-coitus (dpc). Genes involved in inflammatory responses were produced specifically by secretory epithelial cells in the oviduct. At 1.5 and 2.5 dpc, genes involved in pyruvate and glycolysis were enriched in the proximal region, potentially providing metabolic support for developing embryos. Abundant proteins in the oviductal fluid were differentially observed between naturally fertilized and superovulated samples. RNA-seq data were used to identify transcription factors predicted to influence protein abundance in the proteomic data via a novel machine learning model based on transformers of integrating transcriptomics and proteomics data. The transformers identified influential transcription factors and correlated predictive protein expressions in alignment with the in vivo-derived data. In conclusion, our multi-omics characterization and subsequent in vivo confirmation of proteins/RNAs indicate that the oviduct is adaptive and responsive to the presence of sperm and embryos in a spatiotemporal manner.