Abstract P3130: Role Of The Placenta-derived Extracellular Vesicle-cargo Protein, Vasorin In Vascular Dysfunction In Preeclampsia

Background: We recently demonstrated that placenta-derived extracellular vesicles (pEVs) cargo play a role in vascular dysfunction in patients with severe preeclampsia (sPE). We focused our follow up studies on a novel protein vasorin (VASN) that has not as yet been studied in PE. Here, we hypothesize that decreased VASN in EVs cargo plays a significant role in the regulation of vascular endothelial proliferation and function in sPE. Methods: We manipulated VASN by overexpression and knockdown in human aortic endothelial cells (HAEC) and in murine aortic vascular rings (MVR) using adenoviral vectors encoding VASN (AD-VASN) or VASN shRNA (AD-shVASN), respectively. VASN levels in EVs, in HAEC and in MVR with/wo adenoviral overexpression or knockdown of VASN was done by western blotting. Migration of HAEC was studied by a scratch and repair migration assay and contractile function of MVR was assessed by wire myography. A PE-like vascular dysfunction was produced in timed pregnant mice by intravenous injection of an adenoviral vector encoding the short form of FMS-like tyrosine kinase 1 (sFLT-1) on embryonic day 10.5 (E10.5) of pregnancy. Plasma from sFLT-1 -injected and control untreated (UT) mice were collected on E15.5,E17.5 and E19.5. Results: We confirmed our findings with proteomics and using western blotting we detected a significant reduction in VASN levels in both urinary and plasma-derived EVs in sPE patients when compared to normotensive. Moreover, we detected a time-dependent significant reduction of VASN in EVs from plasma of sFLT-1 injected mice whereas UT mice exhibited a time-dependent increase of VASN. Western blotting also confirmed over-expression and knock down of VASN in HAEC and in MVR treated with AD-VASN and AD-shVASN, respectively. Treatment of HAEC with EVs from sPE, but not by EVs from NTP inhibited migration, and pretreatment with AD-VASN but not with AD-shVASN rescued migration upon treatment with EVs from PE. Treatment of MVR with EVs from sPE, but not by EVs from NTP inhibited acetylcholine (ACh)-induced vasorelaxation. Pretreatment with AD-VASN, but not with AD-shVASN rescued ACh-induced vasorelaxation upon treatment with EVs from sPE. Conclusion: Over-expression of VASN using adenoviral vectors rescued inhibitory effects of EVs from sPE on migration of HAEC and ACh-induced vasorelaxation in MVR, suggesting that reduced VASN content in EVs from sPE plays a mechanistic role in vascular dysfunction observed in sPE.