PSGL-1-mediated activation of EphB4 increases the proangiogenic potential of endothelial progenitor cells.
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.
Foubert
Philippe
P
Institut des Vaisseaux et du Sang, Paris, France.
Silvestre
Jean-Sébastien
JS
Souttou
Boussad
B
Barateau
Véronique
V
Martin
Coralie
C
Ebrahimian
Téni G
TG
Leré-Déan
Carole
C
Contreres
Jean Olivier
JO
Sulpice
Eric
E
Levy
Bernard I
BI
Plouët
Jean
J
Tobelem
Gérard
G
Le Ricousse-Roussanne
Sophie
S
D000818:Animals; D001483:Base Sequence; D002448:Cell Adhesion; D002478:Cells, Cultured; D017931:DNA Primers / Q000235:genetics; D019040:E-Selectin / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D036388:Ephrin-B2 / Q000378:metabolism / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology; D053686:Fetal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006614:Hindlimb / Q000098:blood supply; D006801:Humans; D066298:In Vitro Techniques; D007511:Ischemia / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D008297:Male; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D018919:Neovascularization, Physiologic / Q000187:drug effects; D019007:P-Selectin / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D036224:Receptor, EphB4 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D019040:E-Selectin; D036388:Ephrin-B2; D008562:Membrane Glycoproteins; D019007:P-Selectin; C084882:P-selectin ligand protein; D034741:RNA, Small Interfering; C086681:Ephb4 protein, mouse; D036224:Receptor, EphB4