Effects of exosome-like vesicles on cumulus expansion in pigs <i>in vitro</i>

Abstract

Cell-secreted vesicles, such as exosomes, have recently been recognized as mediators of cell communication. A recent study in cattle showed the involvement of exosome-like vesicles in the control of cumulus expansion, a prerequisite process for normal ovulation; however, whether this is the case in other mammalian species is not known. Therefore, this study aimed to examine the presence of exosome-like vesicles in ovarian follicles and their effects on cumulus expansion in vitro in pigs. The presence of exosome-like vesicles in porcine follicular fluid (pFF) was confirmed by transmission electron microscopic observation, the detection of marker proteins, and RNA profiles specific to exosomes. Fluorescently labeled exosome-like vesicles isolated from pFF were incorporated into both cumulus and mural granulosa cells in vitro. Exosome-like vesicles were not capable of inducing cumulus expansion to a degree comparable to that induced by follicle-stimulating hormone (FSH). Moreover, exosome-like vesicles had no significant effects on the expression levels of transcripts required for the normal expansion process (HAS2, TNFAIP6, and PTGS2). Interestingly, FSH-induced expression of HAS2 and TNFAIP6 mRNA, but not of PTGS2 mRNA, was significantly increased by the presence of exosome-like vesicles; however, the degree of FSH-induced expansion was not affected. In addition, porcine exosome-like vesicles had no significant effects on the expansion of mouse cumulus-oocyte complexes. Collectively, the present results suggest that exosome-like vesicles are present in pFF, but they are not efficient in inducing cumulus expansion in pigs.

Characterization of mRNA profiles of the exosome-like vesicles in porcine follicular fluid

“…These pathways are involved in the regulation of ovarian functions, including folliculogenesis, luteogenesis, and steroidogenesis [12–15]. The presence of exosome-like vesicles was also reported in follicular fluids of several other mammalian species, including human, bovine, and pig [16–19]. The miRNA content in the exosome-like vesicles from human and bovine has been studied [16, 17], and these miRNAs are known to target signaling pathways similar to those targeted by equine vesicles.…”

“…Therefore, in the present study, we evaluated the characteristics of transcriptomic profile of mRNA content in exosome-like vesicles from ovarian follicles using pig as a model. The presence of the exosome-like vesicles in porcine follicular fluid (pFF) has been previously reported [19]. As mural granulosa cells (MGCs) are one of the most abundant cell types in ovarian follicles, the transcriptomic profile of the MGCs was also investigated to test whether MGCs are the main producers of the follicular exosome-like vesicles.…”

ATF4 Contributes to Ovulation via Regulating COX2/PGE2 Expression: A Potential Role of ATF4 in PCOS

“…The normal expansion of COC is required for ovulation, which requires the abundant expression of transcripts, such as COX2, PTX3, CD44, TNFAIP6, and HAS2 ( 31 ). Moreover, variations in the ECM secreted from cumulus cells are also essential for oocyte release.…”

Physiological impact of extracellular vesicles on female reproductive system; highlights to possible restorative effects on female age‐related fertility

“…In the recent years, several studies have revealed that exosomes could be released from various parts of the female reproductive tract, including uterine, oviducts epithelium, endometrium, as well as preimplantation embryos, the placenta trophoblastic cells . It is mentioned that exosomes play a substantial role in transmitting specific cargo molecules in the reproductive tract to modulate transcription and translational activity, granulosa cells proliferation and differentiation, cumulus expansion, gametogenesis, normal follicular growth, oocyte maturation, fertilization rate, embryo development, blastocyst formation and implantation, in pregnancy outcome and fertility .…”