Oxygen tension regulates the miRNA profile and bioactivity of exosomes released from extravillous trophoblast cells - Liquid biopsies for monitoring complications of pregnancy

PLoS One. 2017 Mar 28;12(3):e0174514. doi: 10.1371/journal.pone.0174514. eCollection 2017.


Our understanding of how cells communicate has undergone a paradigm shift since the recent recognition of the role of exosomes in intercellular signaling. In this study, we investigated whether oxygen tension alters the exosome release and miRNA profile from extravillous trophoblast (EVT) cells, modifying their bioactivity on endothelial cells (EC). Furthermore, we have established the exosomal miRNA profile at early gestation in women who develop pre-eclampsia (PE) and spontaneous preterm birth (SPTB). HTR-8/SVneo cells were used as an EVT model. The effect of oxygen tension (i.e. 8% and 1% oxygen) on exosome release was quantified using nanocrystals (Qdot®) coupled to CD63 by fluorescence NTA. A real-time, live-cell imaging system (Incucyte™) was used to establish the effect of exosomes on EC. Plasma samples were obtained at early gestation (<18 weeks) and classified according to pregnancy outcomes. An Illumina TrueSeq Small RNA kit was used to construct a small RNA library from exosomal RNA obtained from EVT and plasma samples. The number of exosomes was significantly higher in EVT cultured under 1% compared to 8% oxygen. In total, 741 miRNA were identified in exosomes from EVT. Bioinformatic analysis revealed that these miRNA were associated with cell migration and cytokine production. Interestingly, exosomes isolated from EVT cultured at 8% oxygen increased EC migration, whilst exosomes cultured at 1% oxygen decreased EC migration. These changes were inversely proportional to TNF-α released from EC. Finally, we have identified a set of unique miRNAs in exosomes from EVT cultured at 1% oxygen and exosomes isolated from the circulation of mothers at early gestation, who later developed PE and SPTB. We suggest that aberrant exosomal signalling by placental cells is a common aetiological factor in pregnancy complications characterised by incomplete SpA remodeling and is therefore a clinically relevant biomarker of pregnancy complications.

MeSH terms

  • Adult
  • Arteries / metabolism
  • Biopsy / methods
  • Blotting, Western
  • Cell Movement / genetics
  • Cells, Cultured
  • Chorionic Villi / metabolism
  • Cluster Analysis
  • Exosomes / genetics
  • Exosomes / metabolism*
  • Exosomes / ultrastructure
  • Female
  • Gene Expression Profiling / methods*
  • Human Umbilical Vein Endothelial Cells / cytology
  • Human Umbilical Vein Endothelial Cells / metabolism
  • Humans
  • MicroRNAs / blood
  • MicroRNAs / genetics*
  • Microscopy, Electron, Transmission
  • Oxygen / metabolism*
  • Oxygen / pharmacology
  • Pregnancy
  • Pregnancy Complications / blood
  • Pregnancy Complications / genetics
  • Pregnancy Complications / metabolism
  • Trophoblasts / cytology
  • Trophoblasts / drug effects
  • Trophoblasts / metabolism*
  • Uterus / blood supply


  • MicroRNAs
  • Oxygen

Grants and funding

CS was in receipt of a University of Queensland Fellowship. CS was also funded by the Lions Medical Research Foundation. GER was in receipt of a NHMRC Principal Research Fellowship. This study was supported by University of Queensland Early Career Researcher (ECR) grants to CS, Royal Brisbane and Women’s Foundation, and UQ-Ochsner Seed Fund for Collaborative Research to CS and SL. The ISO17025 accredited research facility was supported by grants from Therapeutics Innovation Australia and the National Collaborative Research Infrastructure Strategy. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.