Flow-Responsive VEGFR-PKCɛ Signaling Mediates Glycolytic Metabolites for Vascular Repair

Aims - Hemodynamic shear stress participates in maintaining vascular redox status. Elucidating flow-mediated endothelial metabolites enables us to discover metabolic biomarkers and therapeutic targets. We posited that flow-responsive VEGF receptor-PKCɛ-PFKFB3 signaling modulates glycolytic metabolites for vascular repair. Results - Bidirectional oscillatory flow (OSS: 0.1 ± 3 dyne·cm^-2 at 1 Hz) up-regulated VEGFR-dependent PKCɛ expression to a greater degree than did unidirectional pulsatile flow (PSS: 23 ± 8 dyne·cm^-2 at 1 Hz) in human aortic endothelial cells (HAEC) (p < 0.05, n=3). PSS and OSS further up-regulated PKCɛ-dependent PFKFB3 expression for glycolysis (p < 0.05, n=4). Constitutively active (CA)-PKCɛ increased, whereas dominant negative (DN)-PKCɛ reduced both basal and maximal extracellular acidification rates (ECAR) for glycolytic flux (p < 0.01, n=4). Metabolomic analysis demonstrated an increase in PKCɛ-dependent glycolytic metabolite, dihydroxyacetone (DHA), but a decrease in gluconeogenic metabolite, aspartic acid (p < 0.05 vs. control, n=6). In a New Zealand White rabbit model, both PKCɛ and PFKFB3 immuno-staining were prominent in the PSS- and OSS-exposed aortic arch and descending aorta. In a transgenic Tg(flk-1:EGFP) zebrafish model, GATA-1a morpholino oligonucleotide injection (to reduce viscosity-dependent shear stress) impaired vascular regeneration after tail amputation (p < 0.01, n=20), which was restored with PKCɛ mRNA rescue (p < 0.05, n=5). As a corollary, siPKCɛ inhibited tube formation and vascular repair, which were restored by DHA treatment in our Matrigel and zebrafish models. Innovation and Conclusion - Flow-sensitive VEGFR-PKCɛ-PFKFB3 signaling increases the glycolytic metabolite, dihydroxyacetone, to promote vascular repair.