Effects of vimentin protein transduction on biological function of vascular endothelial cells

Abstract

The cytoskeleton plays a central role for the integration of biochemical and biomechanical signals across the cell required for complex cellular function. Recent studies indicate that the intermediate filament vimentin is necessary for endothelial function. Vimentin is one of the intermediate filaments that had been considered to be related with cellular integrity and endothelial functions such as cell-cell adhesion, migration and tube formation. It was studied the potential endothelial function of vimentin as a therapeutic protein in HUVECs and its pathways during pHis/TAT-vimentin transduction, using protein delivery system. The results indicated that pHis/TAT-vimentin was effectively transduced in HUVECs and had strong angiogenesis effects though tube formation assay. And it was shown that pHis/TAT-vimentin induced endothelial function is tightly linked to phosphorylation of VASP and activation of protein kinase A (PKA) during tube formation. It acts as stability effects of the cytoskeleton and influences tube formation of endothelial cells. Previous studies found that vasodilator-stimulated phophoprotein (VASP), actin binding protein, has multiple serind/theronine phosphorylation sites. VASP localizes to endothelial junction complexes and co-localizes with ZO-1. To address the role of phospho-VASP in endothelial function, A phospho-specific VASP antibodies targeting phosphorylation site (Ser 157) were used. The site was preferred by PKA. Transduction of pHisTAT-vimentin induced VASP phosphorylation was attenuated by PKA inhibitors in HUVECs. Overall, pHisTAT-vimentin had strong angiogenesis effects and these effects were inhibited by blocking PKA.