Exosome-mediated communication in the ovarian follicle

Abstract

Cells are able to produce and release different types of vesicles, such as microvesicles and exosomes, in the extracellular microenvironment. According to the scientific community, both microvesicles and exosomes are able to take on and transfer different macromolecules from and to other cells, and in this way, they can influence the recipient cell function. Among the different macromolecule cargos, the most studied are microRNAs. MicroRNAs are a large family of non-coding RNAs involved in the regulation of gene expression. They control every cellular process and their altered regulation is involved in human diseases. Their presence in mammalian follicular fluid has been recently demonstrated, and here, they are enclosed within microvesicles and exosomes or they can also be associated to protein complexes. The presence of microvesicles and exosomes carrying microRNAs in follicular fluid could represent an alternative mechanism of autocrine and paracrine communication inside the ovarian follicle. The outcomes from these studies could be important in basic reproductive research but could also be useful for clinical application. In fact, the characterization of extracellular vesicles in follicular fluid could improve reproductive disease diagnosis and provide biomarkers of oocyte quality in ART (Assisted Reproductive Treatment).

Keywords: Exosomes; Extracellular vesicles; MicroRNAs; Ovarian follicle.

Fig. 1

Exosomes in ovarian follicle. shows the possible exchange of microRNAs, long non-coding RNAs, and proteins among different follicular cells by follicular fluid exosomes

Fig. 2

Hypothetical role of miR132, miR212, and miR214 in follicular maturation. miRNAs targeting PTEN could be initially used by the oocyte to activate the primordial follicle, which could subsequently be sequestered by exosomes and sent to FF and then, in a time-dependent manner, could be able to induce the PI3K pathway in GCs and in the oocyte