Project description:The success of the early reproductive events depends on an appropriate communication between gametes/embryos and the oviduct. Extracellular vesicles (EVs) contained in oviductal secretions have been suggested as new players in mediating this crucial cross-talk by transferring their cargo (e.g. proteins, mRNA and small ncRNA) from cell to cell. However, little is known about the oviduct EVs composition and their implications in reproductive success. The objective of our study was to determine the changes of oviductal EVs small ncRNA content under the hormonal influence during the estrous cycle. Methods: EVs, exosomes and microvesicles, were isolated from bovine oviductal fluid at different stages of the estrous cycle (postovulatory-stage, early luteal phase, late luteal phase and pre-ovulatory stage). RNA enriched for short molecules was isolated and used for the preparation of small RNA-seq libraries. RNA-sequencing was performed on an Illumina HiSeq 2500. The obtained sequence reads that passed quality filters were annotated by BLAST alignment to various sets of non-coding and coding RNAs. Read counts were calculated based on the frequency of unique sequences after removal of PCR duplicates. Statistical analysis was done with EdgeR to identify differential small ncRNA abundance across the different stages of the estrous cycle. Results: Small RNA-Seq identified the presence of different types of ncRNAs (miRNAs, rRNA fragments, tRNA fragments, snRNA, snoRNA, and other ncRNAs), which were partially also under hormonal influence. Major differences were found between post-ovulatory and early luteal and the rest of the stages for small ncRNAs. Interesting miRNAs identified in oviductal EVs, miR-34b and miR-449a, showed differential abundance among stages. Dysregulation of these miRNAs has been associated with defective cilia in the oviduct and infertility. Conclusions: Our findings represent the first extensive oviductal signature of bovine oviductal EVs miRNA content and contribute to a better understanding of the role of EVs as modulators of gamete/embryo-maternal interactions.
Project description:The success of the early reproductive events depends on an appropriate communication between gametes/embryos and the oviduct. Extracellular vesicles (EVs) contained in oviductal secretions have been suggested as new players in mediating this crucial cross-talk by transferring their cargo (e.g. proteins, mRNA and small ncRNA) from cell to cell. However, little is known about the oviduct EVs composition and their implications in reproductive success. The objective of our study was to determine the changes of oviductal EVs mRNA content under the hormonal influence during the estrous cycle. Methods: EVs, exosomes and microvesicles, were isolated from bovine oviductal fluid at different stages of the estrous cycle (postovulatory-stage, early luteal phase, late luteal phase and pre-ovulatory stage). Total RNA was isolated and used for the preparation of RNA-seq libraries. RNA-sequencing was performed on an Illumina HiSeq 2500. The obtained sequence reads that passed quality filters were mapped to the bovine genome sequence using Hisat 2. Read counts were calculated with QuasR Qcount and statistical analysis with EdgeR to identify differential mRNA abundance across the different stages of the estrous cycle. Results: RNA-sequencing identified 903 differentially expressed transcripts (FDR<0.001) in bovine oviductal EVs across the estrous cycle. Major differences were found between post-ovulatory and the rest of the stages analyzed.Functional annotation of the differentially abundant mRNAs identified functions related to cilia expression, exosome/vesicles, and many transcripts encoding ribosomal proteins. Conclusions: Our findings represent the first extensive oviductal signature of bovine oviductal EVs mRNA content and contribute to a better understanding of the role of EVs as modulators of gamete/embryo-maternal interactions.
Project description:BackgroundThe success of early reproductive events depends on an appropriate communication between gametes/embryos and the oviduct. Extracellular vesicles (EVs) contained in oviductal secretions have been suggested as new players in mediating this crucial cross-talk by transferring their cargo (proteins, mRNA and small ncRNA) from cell to cell. However, little is known about the oviductal EVs (oEVS) composition and their implications in the reproductive success. The aim of the study was to determine the oEVs content at protein, mRNA and small RNA level and to examine whether the oEVs content is under the hormonal influence of the estrous cycle.ResultsWe identified the presence of oEVs, exosomes and microvesicles, in the bovine oviductal fluid at different stages of the estrous cycle (postovulatory-stage, early luteal phase, late luteal phase and pre-ovulatory stage) and demonstrated that their composition is under hormonal regulation. RNA-sequencing identified 903 differentially expressed transcripts (FDR < 0.001) in oEVs across the estrous cycle. Moreover, small RNA-Seq identified the presence of different types of ncRNAs (miRNAs, rRNA fragments, tRNA fragments, snRNA, snoRNA, and other ncRNAs), which were partially also under hormonal influence. Major differences were found between post-ovulatory and the rest of the stages analyzed for mRNAs. Interesting miRNAs identified in oEVs and showing differential abundance among stages, miR-34c and miR-449a, have been associated with defective cilia in the oviduct and infertility. Furthermore, functional annotation of the differentially abundant mRNAs identified functions related to exosome/vesicles, cilia expression, embryo development and many transcripts encoding ribosomal proteins. Moreover, the analysis of oEVs protein content also revealed changes across the estrous cycle. Mass spectrometry identified 336 clusters of proteins in oEVs, of which 170 were differentially abundant across the estrous cycle (p-value< 0.05, ratio < 0.5 or ratio > 2). Our data revealed proteins related to early embryo development and gamete-oviduct interactions as well as numerous ribosomal proteins.ConclusionsOur study provides with the first molecular signature of oEVs across the bovine estrous cycle, revealing marked differences between post- and pre-ovulatory stages. Our findings contribute to a better understanding of the potential role of oEVs as modulators of gamete/embryo-maternal interactions and their implications for the reproductive success.
Project description:Purpose: Extracellular vesicles (EVs) are nanoparticles that can be secreted by different cells, including cells found within the ovarian follicle. Currently, EVs are considered an important form of intercellular communication, since they carry biological contents. The goal of this study was to survey the effects of small EVs from follicles at different estrous cycle stage in bovine cumulus cells. Methods: We used an established model to obtain follicular fluid (FF) at early and late estrous cycle stage according to corpus luteum appearance, corresponding to low and high progesterone (P4) levels, respectively. We collected FF from 3-6 mm follicles and isolated small EVs, which were used as a supplement during in vitro maturation (IVM). Cumulus cells were collected from cumulus-oocyte complexes (COCs) pools and the RNAs were obtained and subjected to RNA sequencing. Results: The results showed that small EVs from different estrous cycle stage are capable to affect transcripts in cumulus cells and modulate different pathways and biological processes related to oocyte maturation, ovulation and immune response. Conclusion: This study demonstrated that small EVs from low and high P4 group impact the RNA profile in cumulus cells after 9 hours of in vitro maturation.
Project description:Oviductal extracellular vesicles (oEVs) are emerging as key players in the gamete/embryo-oviduct interactions that contribute to successful pregnancy. Various positive effects of oEVs on gametes and early embryos have been found in vitro. To determine whether these effects are associated with changes of embryonic gene expression, the transcriptomes of embryos supplemented with bovine fresh (FeEVs) or frozen (FoEVs) oEVs during in vitro culture compared to controls without oEVs were analyzed by low-input RNA sequencing. Analysis of RNA-seq data revealed 221 differentially expressed genes (DEGs) between FoEV treatment and control, 67 DEGs for FeEV and FoEV treatments, and minor differences between FeEV treatment and control (28 DEGs). An integrative analysis of mRNAs and miRNAs contained in oEVs obtained in a previous study with embryonic mRNA alterations pointed to direct effects of oEV cargo on embryos (1) by increasing the concentration of delivered transcripts; (2) by translating delivered mRNAs to proteins that regulate embryonic gene expression; and (3) by oEV-derived miRNAs which downregulate embryonic mRNAs or modify gene expression in other ways. Our study provided the first high-throughput analysis of the embryonic transcriptome regulated by oEVs, increasing our knowledge on the impact of oEVs on the embryo and revealing the oEV RNA components that potentially regulate embryonic development.
Project description:While follicular fluid (FF) is well known to provide an optimal environment for oogenesis, its functional roles following its release into the oviduct during ovulation are currently elusive. We hypothesized that FF and FF-derived extracellular vesicles (EVs) may be conveyors of signals capable of inducing functionally-relevant transcriptional responses in oviductal cells. The aim of this study was, therefore, to evaluate the effect of FF and FF-derived EVs on the transcriptome of primary bovine oviductal epithelial cells (BOECs). We examined the gene expression of BOECs in three conditions: BOECs cultured with FF, FF-derived EVs, and without supplementations. For each condition, cells were cultured for 6 and 24 h. RNA sequencing results revealed that FF had a stronger effect on BOECs gene expression compared to EVs. We detected 488 and 1998 differentially expressed genes (DEGs) with FF treatment in 6 and 24 h, respectively, whereas only 41 DEGs were detected at 6 h following EV treatment. Pathway analysis of the FF-induced DEGs showed that several pathways were highly enriched, notably oxidative phosphorylation, thermogenesis, arachidonic acid metabolism, and steroid hormone biosynthesis. Some of these pathways have a role in sperm survival, fertilization, and early embryo development. In conclusion, the findings of our study demonstrate for the first time that bovine FF and FF-derived EVs can induce changes in the gene expression of the bovine oviductal cells which, although observed in vitro, may be reflective of in vivo responses which may contribute to a favorable periconceptional microenvironment for sperm survival, fertilization, and early embryo development.
Project description:Early embryonic development occurs in the oviduct, where an ideal microenvironment is provided by the epithelial cells and by the oviductal fluid produced by these cells. The oviductal fluid contains small extracellular vesicles (sEVs), which through their contents, including microRNAs (miRNAs), can ensure proper cell communication between the mother and the embryo. However, little is known about the modulation of miRNAs within oviductal epithelial cells (OECs) and sEVs from the oviductal fluid in pregnant cows. In this study, we evaluate the miRNAs profile in sEVs from the oviductal flushing (OF-sEVs) and OECs from pregnant cows compared to non-pregnant, at 120 h after ovulation induction. In OF-sEVs, eight miRNAs (bta-miR-126-5p, bta-miR-129, bta-miR-140, bta-miR-188, bta-miR-219, bta-miR-345-3p, bta-miR-4523, and bta-miR-760-3p) were up-regulated in pregnant and one miRNA (bta-miR-331-5p) was up-regulated in non-pregnant cows. In OECs, six miRNAs (bta-miR-133b, bta-miR-205, bta-miR-584, bta-miR-551a, bta-miR-1193, and bta-miR-1225-3p) were up-regulated in non-pregnant and none was up-regulated in pregnant cows. Our results suggest that embryonic maternal communication mediated by sEVs initiates in the oviduct, and the passage of gametes and the embryo presence modulate miRNAs contents of sEVs and OECs. Furthermore, we demonstrated the transcriptional levels modulation of selected genes in OECs in pregnant cows. Therefore, the embryonic-maternal crosstalk potentially begins during early embryonic development in the oviduct through the modulation of miRNAs in OECs and sEVs in pregnant cows.