A proangiogenic peptide derived from vascular endothelial growth factor

ABSTRACT Vascular endothelial growth factor receptor-1 (VEGFR-1) is a tyrosine kinase receptor for growth factors of the VEGF family. Endothelial cells express a membrane-bound and a soluble variant of this protein, the latter being mainly considered as a negative regulator of VEGF-A signaling. We previously reported that the soluble form is deposited in the extracellular matrix produced by endothelial cells in culture and is able to promote cell adhesion and migration through binding to α5β1 integrin. In this study, we demonstrate that the Ig-like domain II of VEGFR-1, which contains the binding determinants for the growth factors, is involved in the interaction with α5β1 integrin. To identify domain regions involved in integrin binding, we designed twelve peptides putatively mimicking the domain II surface and tested their ability to inhibit α5β1-mediated endothelial cell adhesion to soluble VEGFR-1 and directly support cell adhesion. One peptide endowed with both these properties was identified and shown to inhibit endothelial cell migration towards soluble VEGFR-1 as well. This peptide directly binds α5β1 integrin, but not VEGF-A, inducing endothelial cell tubule formation