Poster Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Characterisation of the cellular origins of seminal fluid extracellular vesicles     (#448)

Elizabeth Torres Arce 1 2 , Hui-Ming Zhang 3 , Amanda L Anderson 1 2 , Cottrell T Tamessar 1 2 , Shanu Parameswaran 1 2 , Sarah A Robertson 4 , Brett Nixon 1 2 , David J Sharkey 4 , John E Schjenken 1 2
  1. School of Environmental and Life Sciences, College of Engineering, Science and Environment, University of Newcastle, Callaghan, New South Wales, Australia
  2. Hunter Medical Research Institute, Infertility and Reproduction Research Program, New Lambton Heights, New South Wales, Australia
  3. Central Analytical Facility, Research and Innovation division, University of Newcastle, Callaghan, New South Wales, Australia
  4. The Robinson Research Institute and School of Biomedicine, University of Adelaide, Adelaide, South Australia, Australia

Seminal fluid contains one of the most abundant extracellular vesicle populations of any bodily fluid.  Seminal fluid extracellular vesicles (SFEVs) are proposed to perform a variety of functions including supporting sperm development and influencing the physiology of female reproductive tract cells after mating. Prostasomes (EVs from the prostate) have traditionally been thought of as the major population carried by seminal fluid, but SFEVs are heterogeneous and likely comprise EVs released from other male reproductive tract tissues. Here, we used a mouse model to characterise EV populations secreted by the testis, epididymis, vas deferens, seminal vesicles, and prostate to develop greater understanding of the cellular origins of SFEVs. EVs were isolated from the fluids of these tissues using differential ultracentrifugation, then quantified using Nanoparticle Tracking Analysis (NTA) and imaged by Transmission Electron Microscopy (TEM). Assessment of EV abundance using NTA showed that EV numbers fluctuated between 3.19E+11 particles in the prostate, 1.64E+10 particles in the seminal vesicles, and 1.05E+10 particles in the testes, with lower values recorded in the epididymis (i.e. caput = 2.16E+9 particles; corpus = 2.92 E+9 particles, cauda = 3.18E+9 particles), and vas deferens (5.33E+08 particles). Additionally, assessment of the average EV diameter using TEM showed variation across the male reproductive tract with the largest EVs being detected in the seminal vesicles (135.6±1.86nm) and prostate (107±2.14nm), with smaller EV populations in the testes (41.6±8.34nm), cauda (45±11.24nm), corpus (42±12.5nm), and caput (60±5.97nm) epididymis, and vas deferens (43.3±10.0nm). Altogether, these data confirm that EVs are secreted by cells throughout the male reproductive tract and may contribute to the heterogeneous EV population in seminal fluid. Future studies are planned to characterise the proteome of EVs from across the male reproductive tract to identify EV markers that may signify their cellular origin.