title: Low molecular weight fucoidan and heparin enhance the basic fibroblast growth factor-induced tube formation of endothelial cells through heparan sulfate-dependent alpha6 overexpression.
abstract: Basic fibroblast growth factor (FGF-2) activates its high-affinity receptors (FGFRs) but also acts through interaction with heparan sulfate proteoglycans (HSPG). Exogenous polysaccharides also modulate the angiogenic activity of FGF-2. We investigated the effect and mechanism of action of a low molecular weight fucoidan derivative (LMWF) on tube formation by human endothelial cells. LMWF has a better arterial antithrombotic potential in animals than low molecular weight heparin (LMWH). After stimulation of human umbilical vein endothelial cells (HUVEC) by FGF-2 and LMWF (or LMWH), we observed 1) using flow cytometry, an increase in the amount of the alpha6 integrin subunit; 2) using quantitative reverse transcription-polymerase chain reaction, an increase in alpha6 mRNA (higher with LMWF than with LMWH); and 3) using a Matrigel model, an increase in vascular tube formation (also higher with LMWF than with LMWH). A direct link between alpha6 overexpression and vascular tube formation was confirmed by use of an anti-alpha6 antibody: in its presence, there was no capillary network formation on Matrigel. Unexpectedly, an anti-FGFR blocking antibody had no effect on alpha6 over-expression, whereas stripping off the heparan sulfate with heparitinases abolished overexpression. Overall, our data suggest that FGF-2 stimulates alpha6 over-expression in HUVEC, through HSPG but independently from FGFR, and that LMWF (or LMWH) modulates this interaction. Expression of heparan sulfate proteoglycan increases after ischemic injury. Given its antithrombotic properties and its ability to potentiate tube formation of endothelial cells, LMWF may have to be considered for revascularization of ischemic areas.
authors.affiliation: INSERM U428, Faculté des Sciences Pharmaceutiques et Biologiques Université Paris V, 4 avenue de l'Observatoire, 75270 Paris Cedex 06. helley@pharmacie.univ-paris5.fr
authors.forename: Delphine
authors.initials: D
authors.lastname: Chabut
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Fischer
authors.forename: Sylvia
authors.initials: S
authors.lastname: Colliec-Jouault
authors.forename: Ingrid
authors.initials: I
authors.lastname: Laurendeau
authors.forename: Sabine
authors.initials: S
authors.lastname: Matou
authors.forename: Bernard
authors.initials: B
authors.lastname: Le Bonniec
authors.forename: Dominique
authors.initials: D
authors.lastname: Helley
mesh_terms: D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006495:Heparin, Low-Molecular-Weight / Q000494:pharmacology*; D006497:Heparan Sulfate / Q000494:pharmacology*; D006801:Humans; D039503:Integrin alpha6 / Q000096:biosynthesis* / Q000235:genetics; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D011134:Polysaccharides / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
chemical_list: D016222:Fibroblast Growth Factor 2; D006495:Heparin, Low-Molecular-Weight; D006497:Heparan Sulfate; D039503:Integrin alpha6; D011134:Polysaccharides; D012333:RNA, Messenger; C007789:fucoidan