PSGL-1–mediated activation of EphB4 increases the proangiogenic potential of endothelial progenitor cells
Philippe Foubert, … , Gérard Tobelem, Sophie Le Ricousse-Roussanne
Philippe Foubert, … , Gérard Tobelem, Sophie Le Ricousse-Roussanne
Published June 1, 2007
Citation Information: J Clin Invest. 2007;117(6):1527-1537. https://doi.org/10.1172/JCI28338.
View: Text | PDF
Research Article Vascular biology Article has an altmetric score of 9

PSGL-1–mediated activation of EphB4 increases the proangiogenic potential of endothelial progenitor cells

Abstract

Endothelial progenitor cell (EPC) transplantation has beneficial effects for therapeutic neovascularization; however, only a small proportion of injected cells home to the lesion and incorporate into the neocapillaries. Consequently, this type of cell therapy requires substantial improvement to be of clinical value. Erythropoietin-producing human hepatocellular carcinoma (Eph) receptors and their ephrin ligands are key regulators of vascular development. We postulated that activation of the EphB4/ephrin-B2 system may enhance EPC proangiogenic potential. In this report, we demonstrate in a nude mouse model of hind limb ischemia that EphB4 activation with an ephrin-B2–Fc chimeric protein increases the angiogenic potential of human EPCs. This effect was abolished by EphB4 siRNA, confirming that it is mediated by EphB4. EphB4 activation enhanced P selectin glycoprotein ligand-1 (PSGL-1) expression and EPC adhesion. Inhibition of PSGL-1 by siRNA reversed the proangiogenic and adhesive effects of EphB4 activation. Moreover, neutralizing antibodies to E selectin and P selectin blocked ephrin-B2–Fc–stimulated EPC adhesion properties. Thus, activation of EphB4 enhances EPC proangiogenic capacity through induction of PSGL-1 expression and adhesion to E selectin and P selectin. Therefore, activation of EphB4 is an innovative and potentially valuable therapeutic strategy for improving the recruitment of EPCs to sites of neovascularization and thereby the efficiency of cell-based proangiogenic therapy.

Authors

Philippe Foubert, Jean-Sébastien Silvestre, Boussad Souttou, Véronique Barateau, Coralie Martin, Téni G. Ebrahimian, Carole Leré-Déan, Jean Olivier Contreres, Eric Sulpice, Bernard I. Levy, Jean Plouët, Gérard Tobelem, Sophie Le Ricousse-Roussanne

×

Figure 1

Phenotypic and functional characterization of EPCs.

Options: View larger image (or click on image) Download as PowerPoint
Phenotypic and functional characterization of EPCs. (A) EPCs were fixed ...
(A) EPCs were fixed in 90% cold acetone and incubated with the appropriate primary antibody, then with a FITC-coupled secondary antibody. EPCs were characterized according to the presence or absence of endothelial-specific markers including CD31, Tie-2, vWF, vascular endothelial–cadherin (VE-cadherin), and uptake of Dil-acetylated LDL (Dil-Ac LDL) (scale bar: 10 μm) and by their capacity to induce tube formation on Matrigel (scale bar: 100 μm). (B) Flow cytometric analysis of surface antigens on EPCs. EPCs were positive for CD31 but not for monocytic markers CD45, CD14, and CD18 (blue histogram). Isotypic control is represented by the black histogram.