Analysis of the mechanisms involved in miRNA delivery mediated by small extracellular vesicles to COCs and bovine embryos

Abstract

Although reproductive processes are modulated by mechanisms involving endocrine cell communication, recently molecular mechanisms complementary to the endocrine ones have also been related to reproductive functions. Similar to endocrine hormone communication, there are moleculesimportant to the reproductive processes that act in a paracrine way, being carried primarily through extracellular vesicles (EVs). These EVsare nanometer-sized vesicles present in different fluids body, including ovarian follicular fluid, oviductal and uterine fluid, involved in cell-cell communication. EVs play an important role in mediating the exchange of bioactive materials such as miRNAs, mRNAs and proteins. miRNAs are approximately 20 nucleotides longand can regulate gene expression by degrading mRNAs or inhibiting their translation. Some transcriptional profiling studies have been conducted to examine patterns of miRNA-mediated gene expression regulation delivered by EVs. However, some gaps still need to becompleted, including the identification of the mechanisms involved in the delivery of thecontent of VEs (miRNA and mRNA) to cumulus oocyte complexes (COCs) and developing embryos. In this way, the project aims to answer thesegaps and test the hypothesis that EVs from follicular fluid and oviduct areable to deliver specific miRNAs to the COCs and to bovine in vitro embryos. The main objective is to develop a model to modulate thedelivery of bioactive molecules (i.e., miR-21) to COCs and bovine embryos inin vitro via EVs from follicular and oviductal fluid carrying molecules ofactive miRNAs or their inhibitors. Upon the end of this project we hope to identifynew tools to enable the use of EVs to content delivery (miRNA)and the use of these vesicles for diagnostics based on smallfluid volume. Finally, the project will improve our understanding of thedelivery of EV contents, which will accelerate the development of aplatform of miRNAs and mRNAs suitable to be used assupplement during the IVP and as tools in the determination and qualityof gametes and embryos used in vitro. (AU)