title: Mechanistic study of the proangiogenic effect of osteoprotegerin.
abstract: Osteoprotegerin (OPG), a soluble tumour necrosis factor receptor superfamily member, inhibits RANKL-mediated osteoclastogenesis. We have previously reported that OPG enhances the proangiogenic properties of endothelial colony-forming cells (ECFCs) in vitro, and promotes vasculogenesis in vivo. Here we investigated how OPG promotes neovascularisation. Proteomic experiments showed that OPG pretreatment affected ECFCs protein expression in two ways, 23 spots being down-regulated and 6 upregulated. These spots corresponded to proteins involved in cell motility, adhesion, signal transduction and apoptosis. In keeping with these proteomic results, we found that OPG induced ECFCs adhesion to activated endothelium in shear stress conditions, promoting intermediate but not focal adhesion to fibronectin and collagen. Treatment with OPG induced a reorganization of the ECFCs cytoskeleton, with the emergence of cell protrusions characteristic of a migratory phenotype. These effects correlated with decreased FAK phosphorylation and enhanced integrin αVβ3 expression. OPG drastically reduced caspase-3/7 activities and maintained ECFCs viability after 48 h of treatment. All these effects were significantly attenuated by ECFCs incubation with the CXCR4 antagonist AMD-3100, and by prior heparan sulphate proteoglycan disruption. The proangiogenic properties of OPG appeared to be mediated by the proteoglycan syndecan-1, although OPG 1-194 lacking its heparin-binding domain still had pro-vasculogenic effects in vitro and in vivo. These results suggest that OPG may interact with ECFCs by binding to HSPGs/syndecan-1, thereby induce an anti-adhesive effect and promoting ECFCs migration through a SDF-1/CXCR4 dependent pathway.
authors: Université Paris Descartes, Sorbonne Paris Cité, Paris, France. benslimane.zahia@yahoo.fr
authors: Zahia
authors: Z
authors: Benslimane-Ahmim
authors: Florence
authors: F
authors: Poirier
authors: Claudine
authors: C
authors: Delomenie
authors: Anna
authors: A
authors: Lokajczyk
authors: Françoise
authors: F
authors: Grelac
authors: Isabelle
authors: I
authors: Galy-Fauroux
authors: Amel
authors: A
authors: Mohamedi
authors: Anne-Marie
authors: AM
authors: Fischer
authors: Dominique
authors: D
authors: Heymann
authors: Didier
authors: D
authors: Lutomski
authors: Catherine
authors: C
authors: Boisson-Vidal
mesh_terms: D001596:Benzylamines; D053148:Caspase 3 / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000080027:Cyclams; D003599:Cytoskeleton / Q000187:drug effects; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000502:physiology; D006571:Heterocyclic Compounds; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D053244:Osteoprotegerin / Q000378:metabolism / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D040901:Proteomics; D053668:Syndecan-1 / Q000378:metabolism
chemical_list: D001596:Benzylamines; D000080027:Cyclams; D006571:Heterocyclic Compounds; D039302:Integrin alphaVbeta3; D053244:Osteoprotegerin; D053668:Syndecan-1; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D053148:Caspase 3; C088327:plerixafor