Hypoxia-induced changes in the bioactivity of cytotrophoblast-derived exosomes

Migration of extravillous trophoblasts (EVT) into decidua and myometrium is a critical process in the conversion of maternal spiral arterioles and establishing placenta perfusion. EVT migration is affected by cell-to-cell communication and oxygen tension. While the release of exosomes from placental cells has been identified as a significant pathway in materno-fetal communication, the role of placental-derived exosomes in placentation has yet to be established. The aim of this study was to establish the effect of oxygen tension on the release and bioactivity of cytotrophoblast (CT)-derived exosomes on EVT invasion and proliferation. CT were isolated from first trimester fetal tissue (n = 12) using a trypsin-deoxyribonucleasedispase/ Percoll method. CT were cultured under 8%, 3% or 1% O2 for 48 h. Exosomes from CT-conditioned media were isolated by differential and buoyant density centrifugation. The effect of oxygen tension on exosome release (mg exosomal protein/10(6)cells/48 h) and bioactivity were established. HTR-8/SVneo (EVT) were used as target cells to establish the effect (bioactivity) of exosomes on invasion and proliferation as assessed by real-time, live-cell imaging (Incucyte (TM)). The release and bioactivity of CT-derived exosomes were inversely correlated with oxygen tension (p