Lightning Talk + Poster ESA-SRB-NZSE-CaSR 2026 in conjunction with ENSA

Seminal extracellular vesicles originate throughout the male reproductive tract and retain tissue-of-origin signatures  (144416)

Elizabeth Torres-Arce 1 2 , Hui-Ming Zhang 3 , Amanda L Anderson 1 2 , Shanmanthi Parameswaran 1 2 , Judith Weidenhofer 4 5 , Brett Nixon 1 2 , David J Sharkey 6 , John E Schjenken 1 2
  1. Centre for Reproductive Science, School of Science, College of Engineering, Science and Environment, University of Newcastle, Newcastle, NSW 2308, Australia
  2. Reproductive and Family Health Research Program, Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
  3. Central Analytical Facility, Research and Innovation division, University of Newcastle, Callaghan, NSW 2308, Australia
  4. School of Biomedical Sciences and Pharmacy, College of Health, Medicine and Wellbeing, University of Newcastle, Ourimbah, NSW 2258, Australia
  5. Precision Medicine Research Program, Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
  6. Robinson Research Institute, and School of Pharmacy and Biomedical Science, Adelaide University, Adelaide, SA 5005, Australia

Background: Seminal extracellular vesicles (SEVs) have considerable potential as non-invasive biomarkers of male reproductive health. However, diagnostic and therapeutic utility is limited by an incomplete understanding of their cellular origins. Although SEVs have historically been considered prostate-derived, extracellular vesicles (EVs) are secreted throughout the male reproductive tract (MRT). The relative contribution of individual MRT tissues to the SEV population remains poorly defined. Here, we characterised EV populations secreted by distinct regions of the MRT and evaluated candidate tissue of origin markers. 

Methods: EVs were isolated from mouse seminal vesicles, prostate, testis, epididymis (caput, corpus and cauda), and vas deferens using differential ultracentrifugation. EV concentration and morphology was quantified by nanoparticle tracking analysis or transmission electron microscopy (n=16 mice) and compared to EVs isolated from ejaculated semen (n=3 mice). Immunogold labelling (n=4 mice) was used to identify EV tissue of origins using candidate biomarkers. 

Results: EV abundance varied across the MRT, with higher concentrations in prostate and seminal vesicle fluids compared to testicular, epididymal and vas deferens fluid. EV size also varied across the MRT, with prostate- and seminal vesicle- derived EVs significantly larger than those from the testis, epididymis and vas deferens (p<0.05). This heterogeneity matched the EVs identified in ejaculated semen. Flotillin-1 and CD63-positive EVs were detected throughout the male reproductive tract; however, these EVs were significantly larger in the testis than in the seminal vesicle, prostate, corpus and cauda (p<0.05). Furthermore, immunogold labelling identified Mucin-6 exclusively in seminal vesicle-derived EVs, whereas Transglutaminase-4 was detected in both seminal vesicle- and prostate-derived EV populations. 

Conclusion: Distinct regions of the MRT secrete phenotypically distinct EV populations that differ in abundance, morphology and protein composition. These findings demonstrate that EVs retain tissue-specific characteristics, providing a foundation for the development of non-invasive biomarkers to detect and localise pathologies throughout the MRT.