Decreased Extracellular Vesicle Vasorin in Severe Preeclampsia Plasma Mediates Endothelial Dysfunction

BackgroundPreeclampsia (PE) is a serious pregnancy complication affecting 5-8% of pregnancies globally. It is a leading cause of maternal and neonatal morbidity and mortality. Despite its prevalence, the underlying mechanisms of PE remain unclear. This study aimed to determine the potential role of vasorin (VASN) in PE pathogenesis by investigating its levels in extracellular vesicles (EV) and its effects on vascular function. Methods & ResultsWe conducted unbiased proteomics on urine-derived EV from severe PE (sPE) and normotensive pregnant women (NTP), identifying differential protein abundances. Out of one hundred and twenty proteins with [≥] {+/-}1.5-fold regulation at P<0.05 between sPE and NTP, we focused on Vasorin (VASN), which is downregulated in sPE in urinary EV, in plasma EV and in the placenta and is a known regulator of vascular function. We generated EV with high VASN content from both human and murine placenta explants (Plex EV), which recapitulated disease-state-dependent effects on vascular function observed when treating murine aorta rings (MAR) or human aortic endothelial cells (HAEC) with murine or human plasma-derived EV. In normal murine pregnancy, VASN increases with gestational age (GA), and VASN is decreased in plasma EV, in placenta tissue and in Plex EV after intravenous administration of adenovirus encoding short FMS-like tyrosine kinase 1 (sFLT-1), a murine model of PE (murine-PE). VASN is decreased in plasma EV, in placenta tissue and in EV isolated from conditioned media collected from placenta explants (Plex EV) in patients with sPE as compared to NTP. Human sPE and murine-PE plasma EV and Plex EV impair migration, tube formation, and induces apoptosis in human aortic endothelial cells (HAEC) and inhibit acetylcholine-induced vasorelaxation in murine vascular rings (MAR). VASN over-expression counteracts the effects of sPE EV treatment in HAEC and MAR. RNA sequencing revealed that over-expression or knock down of VASN in HAEC results in contrasting effects on transcript levels of hundreds of genes associated with vasculogenesis, endothelial cell proliferation, migration and apoptosis. ConclusionsThe data suggest that VASN, delivered to the endothelium via EV, regulates vascular function and that the loss of EV VASN may be one of the mechanistic drivers of PE. CLINICAL PERSPECTIVEWhat is New O_LIVASN in circulating plasma EV in sPE is reduced compared with VASN content in plasma EV of gestational age-matched pregnant women. C_LIO_LIVASN is encapsulated and transported in EV and plays a pro-angiogenic role during pregnancy. C_LIO_LIVASN should be explored both for its pro-angiogenic mechanistic role and as a novel biomarker and potential predictive diagnostic marker for the onset and severity of PE. C_LI What Are the Clinical Implications? O_LIVASN plays a role in maintaining vascular health and the normal adaptive cardiovascular response in pregnancy. A decrease of VASN is observed in sPE patients contributing to cardiovascular maladaptation. C_LIO_LIStrategies to boost diminished VASN levels and/or to pharmacologically manipulate mechanisms downstream of VASN may be explored for potential therapeutic benefit in PE. C_LIO_LIThe decrease in EV-associated VASN could potentially be used as a (predictive) biomarker for PE. C_LI