Human seminal extracellular vesicles carry microRNAs predicted to regulate female reproductive tract immune function — ASN Events
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Human seminal extracellular vesicles carry microRNAs predicted to regulate female reproductive tract immune function (#512)

Heidi J Gilchrist 1 2 , Cottrell T Tamessar 1 2 3 , Shanu Parameswaran 1 2 , Elizabeth Torres-Arce 1 2 , Ellen L Stonestreet 1 2 , Sarah A Robertson 4 , David J Sharkey 4 , John E Schjenken 1 2
  1. Centre for Reproductive Science, School of Science, College of Engineering, Science and Environment, The University of Newcastle, Callaghan, NSW, Australia
  2. Reproductive and Family Health Research Program, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
  3. Systems Biology Research Center, School of Bioscience, University of Skövde, Skövde, Sweden
  4. Robinson Research Institute, and School of Pharmacy and Biomedical Sciences, College of Health, Adelaide University, Adelaide, South Australia, Australia

Background: Seminal extracellular vesicles (SEVs) are key mediators of communication between the male and female reproductive tracts (FRT). Although several SEV proteins have been implicated in this process, the contribution of SEV-associated miRNAs remains poorly understood. Here, we investigated the potential for immune-regulatory miRNAs carried by SEVs to regulate FRT immune responses.

Methods: Bioinformatic analysis of RNA-sequencing data generated from SEV-treated and untreated ectocervical epithelial (ECT1) cells was performed to predict SEV-derived signalling mediators and investigate their downstream targets. SEVs were enriched from normozoospermic semen samples (n=5) and characterised according to established protocols. qPCR was used to confirm the presence of candidate miRNAs.

Results: Bioinformatics assessment identified miRNA-146a-5p, miRNA-155-5p, and miRNA-223-3p (all p<0.05) as predicted upstream regulators of genes differentially regulated (-1.5≤FC≥1.5, p.adj≤0.05) by SEVs. qPCR evaluation of the target miRNAs in SEVs identified abundant levels of miRNA-146a-5p and miRNA-155-5p in SEVs. While miRNA-223-3p was also carried by SEVs, it was present at substantially lower levels than both miRNA-146a-5p and miRNA-155-5p (>90% reduction). Interestingly, marked donor-to-donor variation was observed in the abundance of each miRNA, suggesting heterogeneity in SEV cargo composition. Consistent with the presence of these miRNAs in SEVs, several predicted target genes, many of which are involved in the regulation of immune responses, were differentially expressed (all p.adj=<0.05) in a manner consistent with miRNA-mediated repression. Predicted targets of miRNA-146a-5p included; Peroxisomal membrane protein 11C (FC=-1.64), Interleukin 1 Receptor Accessory Protein-Like 2 (FC=-1.93) and Surfactant Protein D (FC=-2.05). The predicted miRNA-155-5p gene target Methyltransferase-like protein 7A (FC=-2.56) was also down-regulated, as were the predicted miR-223-3p gene targets Cluster of Differentiation 36 (FC=-1.57) and Epidermal Growth Factor (FC=-1.62).

Conclusion: Overall, these findings suggest that miRNA-146a-5p, miRNA-155-5p and miRNA-223-3p are candidate SEV-borne signalling mediators that may contribute to the regulation of the FRT response to seminal fluid.