The Knowns and Unknowns about Epididymal Extracellular Vesicles in Different Animal Species

Abstract

Sperm maturation during epididymal transit is a long and complex process. Although the roles of epididymal extracellular vesicles (EVs) on sperm quality have been extensively studied in recent years, there are still a lot of unexplored areas and too few species that are studied. The objective of this review is to focus on the contribution of epididymal EVs through the apocrine secretion of key factors, including proteins and small RNAs. Furthermore, the authors explore the alterations in the content of these vesicles related to male fertility and the effects of environmental stressors, and how these factors vary across taxa. Last, potential applications are covered, and the next steps in that field of research are highlighted.

Transfer of Galectin-3-Binding Protein via Epididymal Extracellular Vesicles Promotes Sperm Fertilizing Ability and Developmental Potential in the Domestic Cat Model

“…As we recently reviewed, there are still many unknows regarding epididymal EVs in many different species [ 54 ]. However, the present findings improve our understanding of a key sperm protein carried by EVs that is involved in successful sperm–oocyte interactions and fast completion of the first cell cycle.…”

Information Flow between Parents and Offspring Is Essential for Successful Development

“…One of the first such recognized interactions involved the transfer of EVs from epididymal cells to spermatozoa undergoing maturation within the epididymis [ 7 ]. Since then, EVs have been analyzed in detail using mass spectrometry and are now known to contain many proteins and diverse species of RNA [ 8 ]. The two EV studies reported in this Special Issue confirmed that EVs function to modulate the physiology of the mammalian female reproductive tract, and besides participating in embryo development and implantation, they can be used to enhance in vitro embryo development and modulate embryo transcription after embryo transfer [ 5 , 6 ].…”