Spermatozoa, acts as an external cue and alters the cargo and production of the extracellular vesicles derived from oviductal epithelial cells

Oviduct provides optimum physiological and biochemical milieu essential for successful fertilization as well as early embryo development and facilitates functional maturation of spermatozoa. Studies have showed that spermatozoa have the capability to alter gene expression in bovine oviductal epithelial cells (BOECs) remotely via secreted bio-active particles, thus acting as a cue to oviduct prior to their arrival. However, very little attention has been paid to the question whether spermatozoa could alter the cargo of extracellular vesicles (EV) derived from BOECs. Therefore, the aim of this study was to investigate the alterations in small non-coding RNAs in EV cargo derived from BOECs when these BOECs were incubated with spermatozoa in a contact and non-contact co-culture models. After 4 hours of incubation the EVs were purified from the conditioned media, followed by small non-coding sequencing of the BOEC derived EVs. Our results revealed distinct cargo in form of mRNA, miRNA, tRNA, piRNA, present in EVs purified from contact and non-contact co-culture models when compared to the control. The pathway enrichment analysis revealed that EV mRNA from direct co-culture was associated with genes that were involved in the activation of multi-vesicular body (MVB) and microtubule pathways. Similarly, the EV mRNA derived from non-contact conditioned media, the genes were associated with suppression of immune system. Moreover, miR-100 and miR-99a-5p were found to be upregulated in contact co-culture models, the target genes of which regulate phosphatidylinositol signalling system. The findings of this study suggest that spermatozoa, in contact as well as remotely, alter the EV cargos of female reproductive tract epithelial cells which might be playing an essential role in pre and post-fertilization events. These cellular events including inter-cellular communication via EVs are essential for a healthy pregnancy to occur.