Poster Presentation ESA-SRB-APEG-NZSE 2022

Human Seminal Fluid Extracellular Vesicles Induce Pro-Inflammatory Cytokine Responses in Female Cervical Cells In Vitro (#378)

Cottrell T Tamessar 1 2 , Brett Nixon 1 2 , Elizabeth G Bromfield 1 2 , David J Sharkey 3 , Sarah A Robertson 3 , John E Schjenken 1 2
  1. Priority Research Centre for Reproductive Science and School of Environmental and Life Sciences, The University of Newcastle, Newcastle, NSW, Australia
  2. Infertility and Reproduction Research Program, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
  3. Robinson Research Institute and Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia

Seminal fluid interacts with epithelial cells lining the female reproductive tract to induce pro-inflammatory cytokines and initiate immune adaption for pregnancy. Factors in seminal fluid including transforming growth factor (TGF)β family members have been identified as key signalling agents, but do not fully account for the female response. Seminal fluid extracellular vesicles (SFEVs) likely have signalling potential given their suggested roles in fertility and immune regulation; however, their signalling capacity is yet to be characterised in humans. To assess the impact of human SFEVs on female reproductive tract immune responses, we used a well-established human ectocervical epithelial (Ect1) cell in-vitro culture model. Seminal fluid was collected from normozoospermic donors and SFEVs were isolated in accordance with the Minimal Information for Studies of Extracellular Vesicles guidelines. Ect1:SFEV interactions were assessed by immunofluorescence using biotin-labelled SFEVs (n=5/group). Cytokine gene expression profiles were assayed by qPCR (n=8/group). SFEVs were observed to dock with Ect1 cells and deposit biotinylated protein cargo within 5-minutes post-incubation, with SFEV cargo subsequently detected in Ect1 cells throughout an 8-hour incubation. Following incubation with SFEVs, Ect1 cells exhibited changes in gene expression of several pro-inflammatory cytokines previously documented to be induced by seminal fluid, but not regulated by TGFβ. These included IL1A (p≤0.01, 2.6-fold), IL6 (p≤0.01, 2.8-fold), CXCL2 (p≤0.01, 2.3-fold) and CCL20 (p≤0.05, 5.6-fold), all of which were significantly induced in Ect1 cells following exposure to SFEVs compared to untreated cells. In contrast, genes whose regulation has not been attributed to seminal fluid, such as GUSB and HPRT, were not regulated by SFEVs. This study provides evidence that SFEVs communicate with female cervical cells, modifying the female reproductive tract immune environment. Our current studies are exploiting transcriptomics to delineate the full breadth of gene expression changes and identify SFEV mediators that may influence the female immune response at conception.