Sperm-to-SEV cargo transfer reveals bidirectional and donor-specific sperm–seminal extracellular vesicle communication — ASN Events
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Sperm-to-SEV cargo transfer reveals bidirectional and donor-specific sperm–seminal extracellular vesicle communication (#534)

Shanu Parameswaran 1 2 , Elizabeth Torres-Arce 1 2 , Cottrell T Tamessar 1 2 3 , Shannon P Smyth 4 , Elizabeth G Bromfield 1 2 4 , Brett Nixon 1 2 , David J Sharkey 5 , John E Schjenken 1 2
  1. Reproductive and Family Health Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
  2. Centre for Reproductive Science, School of Science, College of Engineering, Science and Environment, University of Newcastle, Callaghan, NSW, Australia
  3. Systems Biology Research Center, School of Bioscience, University of Skövde, Skövde, Sweden
  4. School of BioSciences. Faculty of Science, Bio21 Institute, The University of Melbourne, Parkville, VIC, Australia
  5. Robinson Research Institute, and School of Pharmacy and Biomedical Science, College of Health, Adelaide University, Adelaide, SA, Australia

Background: Seminal extracellular vesicles (SEVs) modulate sperm function through the transfer of bioactive cargo. While SEV–sperm communication is generally considered unidirectional, extracellular vesicles can undergo transient “kiss-and-run” interactions that may permit bidirectional cargo exchange. In this study, we assessed the hypothesis that SEV–sperm communication is bidirectional, enabling SEVs to both deliver and acquire cargo from sperm. Additionally, we further hypothesised that the extent of SEV–sperm cargo exchange and its functional consequences may differ between donor-matched and donor-unmatched SEV–sperm pairings.

Methods: Sperm and SEVs were collected from normozoospermic donors using established approaches. DiO-labelled sperm were incubated with unlabelled SEVs in either donor-matched (sperm and SEVs from the same individual, n = 3) or donor-unmatched (sperm and SEVs from different individuals, n = 5) pairings. Following incubation, sperm-SEV interactions were assessed using fluorescence microscopy, with SEVs visualised following conjugation to sulfate-coated latex beads. Sperm motility was assessed before and after co-incubation with SEVs using computer assisted sperm analysis.

Results: Following co-incubation of DiO-labelled sperm with unlabelled SEVs, transfer of sperm-derived lipid to SEVs was observed in all samples examined. Notably, a greater proportion of sulfate-coated latex beads exhibited fluorescence following co-incubation of matched donor samples (22.16%) compared with unmatched donor samples (7.68%; p<0.05). Assessment of sperm motility showed no change in either total nor progressive motility when SEVs were incubated with matched sperm samples. In comparison a significant reduction in both total (20% reduction, p<0.05), and progressive motility (18% reduction, p<0.05) was observed when sperm were incubated with SEV from an unmatched donor.

Conclusions: This study provides the first evidence of sperm-to-SEV cargo transfer and supports a model of bidirectional sperm–SEV communication. Our findings suggest donor-specific selectivity influences sperm–SEV interactions and may contribute to the regulation of sperm function.