In order to examine the effect of endothelial-derived extracellular vesicles (eEVs) on the mechanism of flow-induced dilation (FID) composition, formation, and functional effects on the mechanism of FID were examined from two different eEV subtypes, one produced from ceramide, the other from plasminogen-activator inhibitor 1 (PAI-1). Using videomicroscopy, internal diameter changes in response to increases in flow were measured in human adipose resistance arteries acutely exposed (30min) to eEVs derived from cultured endothelial cells exposed to ceramide or PAI-1. FID was significantly impaired following exposure to 500K/mL (K=1000) of ceramide-induced eEVs (Cer-eEVs) but unaffected by 250K/mL. FID was reduced in the presence of PEG-catalase following administration of 250K/mL of Cer-eEVs and PAI-1 eEVs whereas Nω-Nitro-L-arginine methyl ester (ʟ-NAME) had no effect. Pathway analysis following protein composition examination using liquid chromatography tandem mass spectrometry (LC MS/MS) demonstrated that both subtypes were strongly linked to similar biological functions, primarily, mitochondrial dysfunction. Flow cytometry was utilized to quantify eEVs in the presence or absence of PBA and mito PBA, cytosolic and mitochondrial-targeted anti-oxidants, respectively. eEV formation was significantly and dramatically reduced with mito PBA treatment. In conclusion, eEVs have a biphasic effect with higher doses impairing and lower doses shifting the mediator of FID from nitric oxide (NO) to hydrogen peroxide (H2O2). Despite differences in protein content, eEVs may alter vascular function in similar directions regardless of the stimulus used for their formation. Further, mitochondrial ROS production is required for the generation of these vesicles.
- extracellular vesicles
- Copyright © 2016, American Journal of Physiology-Heart and Circulatory Physiology