Bovine Follicular Fluid Derived Extracellular Vesicles Modulate the Viability, Capacitation and Acrosome Reaction of Bull Spermatozoa

Abstract

While follicular fluid (FF) is known to enhance the functional properties of spermatozoa, the role of FF-derived extracellular vesicles (EVs) in this respect is unknown. We hypothesized that bovine FF EVs convey signals to spermatozoa supporting sperm viability, inducing sperm capacitation and acrosome reaction. In this study, the effects of bovine FF EVs on sperm functions are evaluated. Irrespective of the size of the follicles which FF EVs had originated from, they were capable of supporting sperm viability, inducing capacitation and acrosome reaction. These effects were specific to the source of bovine FF EVs, as human-cell-line-derived or porcine FF EVs did not affect spermatozoa viability or induced capacitation and acrosome reaction. A minimum of 5 × 105 EVs/mL was adequate to maintain sperm viability and induce capacitation and acrosome reaction in spermatozoa. Interestingly, with FF EV trypsin treatment, FF EVs lost their ability to support sperm functions. In conclusion, this study demonstrates that bovine FF EVs can support spermatozoa function and may contribute to a favorable periconceptional microenvironment. This is an important aspect of the interactions between different sexes at the earliest stages of reproduction and helps to understand molecular mechanisms modulating processes such as sperm competition and female cryptic choice.

Role of extracellular vesicles in intercellular communication during reproduction

“…EVs regulate different reproductive events such as sperm maturation (Caballero et al, 2010), sperm viability, capacitation, and acrosome reaction (Hasan et al, 2021b), oocyte maturation (J. Silveira et al, 2014), recognition of conceptus in implantation (Ruiz-González et al, 2015), maintenance of pregnancy, and parturition (Salomon et al, 2018).…”

“…EVs play vital roles in intercellular communication related to follicular development and oocyte quality. Concentration of EVs negatively correlates with the size of follicles (Hasan et al, 2021a). Bovine follicular fluid derived EVs affects the transcriptomes of oocytes, adjacent granulosa cells and oviductal epithelial cells, playing essential roles in oocyte maturation and embryo development (Dalanezi et al, 2017;Hasan et al, 2020).…”

“…EVs regulate different reproductive events such as sperm maturation (Caballero et al, 2010), sperm viability, capacitation and acrosome reaction (Hasan et al, 2021), oocyte maturation (Silveira et al, 2014), recognition of conceptus in implantation (Ruiz-González et al, 2015), maintenance of pregnancy and parturition (Salomon et al, 2018). Moreover, a growing body of evidence indicate that EVs are also involved in pathological conditions such as early pregnancy loss, polycystic ovaries, endometriosis, gestational diabetes mellitus, hypertension and preeclampsia (Rooda et al, 2020).…”

“…The presence of EVs in follicular fluid has been well established (Hasan et al, 2020(Hasan et al, , 2021Reshi et al, 2021). EVs play vital roles in intercellular communication related to follicular development and oocyte quality.…”

The Non-Gastric H+/K+ ATPase (ATP12A) Is Expressed in Mammalian Spermatozoa

“…Coverslips were then mounted onto slides using ProLong Gold Antifade Reagent with DAPI (Thermo Fisher Scientific, Waltham, MA, USA) and examined with NIKON Eclipse 6004 microscope by using 10× or 40× objectives, and images were acquired by NIKON digital camera DXM1200. For acrosomal co-staining [78,79], cells were incubated with TRITC-coupled peanut agglutinin (PNA) (Merck/MilliporeSigma, Burlington, MA, USA) diluted in PBS (final concentration 30 mg/mL) for 30 min at room temperature after secondary antibody incubation. After removing an excess of fluorescence-conjugated lectin by three washes with PBS, the coverslips were processed as mentioned above.…”