title: Oxidized LDL-induced angiogenesis involves sphingosine 1-phosphate: prevention by anti-S1P antibody.
abstract: OBJECTIVE
  Neovascularization occurring in atherosclerotic lesions may promote plaque expansion, intraplaque haemorrhage and rupture. Oxidized LDL (oxLDL) are atherogenic, but their angiogenic effect is controversial; both angiogenic and anti-angiogenic effects have been reported. The angiogenic mechanism of oxLDL is partly understood, but the role of the angiogenic sphingolipid, sphingosine 1-phosphate (S1P), in this process is not known. Thus, we investigated whether S1P is involved in the oxLDL-induced angiogenesis and whether an anti-S1P monoclonal antibody can prevent this effect.
  
  
  METHODS
  Angiogenesis was assessed by capillary tube formation by human microvascular endothelial cells (HMEC-1) cultured on Matrigel and in vivo by the Matrigel plug assay in C57BL/6 mice.
  
  
  RESULTS
  Human oxLDL exhibited a biphasic angiogenic effect on HMEC-1; low concentrations were angiogenic, higher concentrations were cytotoxic. The angiogenic response to oxLDL was blocked by the sphingosine kinase (SPHK) inhibitor, dimethylsphingosine, by SPHK1-siRNA and by an anti-S1P monoclonal antibody. Moreover, inhibition of oxLDL uptake and subsequent redox signalling by anti-CD36 and anti-LOX-1 receptor antibodies and by N-acetylcysteine, respectively, blocked SPHK1 activation and tube formation. In vivo, in the Matrigel plug assay, low concentrations of human oxLDL or murine oxVLDL also triggered angiogenesis, which was prevented by i.p. injection of the anti-S1P antibody.
  
  
  CONCLUSIONS
  These data highlight the role of S1P in angiogenesis induced by oxLDL both in HMEC-1 cultured on Matrigel and in vivo in the Matrigel plug model in mice, and demonstrate that the anti-S1P antibody effectively blocks the angiogenic effect of oxLDL.
authors.affiliation: Inserm UMR-1048, Toulouse, France; Department of Biochemistry, University of Toulouse, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Camaré
authors.forename: Magali
authors.initials: M
authors.lastname: Trayssac
authors.forename: Barbara
authors.initials: B
authors.lastname: Garmy-Susini
authors.forename: Elodie
authors.initials: E
authors.lastname: Mucher
authors.forename: Roger
authors.initials: R
authors.lastname: Sabbadini
authors.forename: Robert
authors.initials: R
authors.lastname: Salvayre
authors.forename: Anne
authors.initials: A
authors.lastname: Negre-Salvayre
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D006801:Humans; D008077:Lipoproteins, LDL; D008246:Lysophospholipids / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000187:drug effects; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D000099157:Sphingosine Kinase
chemical_list: D000911:Antibodies, Monoclonal; D008077:Lipoproteins, LDL; D008246:Lysophospholipids; D017853:Phosphotransferases (Alcohol Group Acceptor); D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; D013110:Sphingosine; D000099157:Sphingosine Kinase; C099252:oxidized low density lipoprotein; C060506:sphingosine 1-phosphate; C061800:N,N-dimethylsphingosine