VEGF internalization is not required for VEGFR-2 phosphorylation in bioengineered surfaces with covalently linked VEGF.


Journal Article

Vascular endothelial growth factor (VEGF) is known to activate proliferation, migration, and survival pathways in endothelial cells through phosphorylation of VEGF receptor-2 (VEGFR-2). VEGF has been incorporated into biomaterials through encapsulation, electrostatic sequestration, and covalent attachment, but the effect of these immobilization strategies on VEGF signaling has not been thoroughly investigated. Further, although growth factor internalization along with the receptor generally occurs in a physiological setting, whether this internalization is needed for receptor phosphorylation is not entirely clear. Here we show that VEGF covalently bound through a modified heparin molecule elicits an extended response of pVEGFR-2 in human umbilical vein endothelial cells (HUVECs) and that the covalent linkage reduces internalization of the growth factor during receptor endocytosis. Optical tweezer measurements show that the rupture force required to disrupt the heparin-VEGF-VEGFR-2 interaction increases from 3-8 pN to 6-12 pN when a covalent bond is introduced between VEGF and heparin. Importantly, by covalently binding VEGF to a heparin substrate, the stability (half-life) of VEGF is extended over three-fold. Here, mathematical models support the biological conclusions, further suggesting that VEGF internalization is significantly reduced when covalently bound, and indicating that VEGF is available for repeated phosphorylation events.

Full Text

Duke Authors

Cited Authors

  • Anderson, SM; Shergill, B; Barry, ZT; Manousiouthakis, E; Chen, TT; Botvinick, E; Platt, MO; Iruela-Arispe, ML; Segura, T

Published Date

  • September 2011

Published In

Volume / Issue

  • 3 / 9

Start / End Page

  • 887 - 896

PubMed ID

  • 21826315

Pubmed Central ID

  • 21826315

Electronic International Standard Serial Number (EISSN)

  • 1757-9708

International Standard Serial Number (ISSN)

  • 1757-9694

Digital Object Identifier (DOI)

  • 10.1039/c1ib00037c


  • eng