Effector protease receptor 1 mediates the mitogenic activity of factor Xa for vascular smooth muscle cells in vitro and in vivo.
The binding of 125I-factor Xa to human aortic smooth muscle cell (SMC) monolayers was studied. At 4 degreesC, 125I-factor Xa bound to a single class of binding sites with a dissociation constant value of 3.6+/-0.7 nM and a binding site density of 11,720+/-1,240 sites/cell (n = 9). 125I-factor Xa binding was not affected by factor X, thrombin, or by DX9065, a direct inhibitor of factor Xa, but was inhibited by factor Xa (IC50 = 5.4+/-0.2 nM; n = 9) and by antibodies specific for the effector cell protease receptor 1 (EPR-1), a well-known receptor of factor Xa on various cell types. A factor X peptide duplicating the inter-EGF sequence Leu83-Leu88-(Gly) blocked the binding of 125I-factor Xa to these cells in a dose-dependent manner (IC50 = 110+/-21 nM). Factor Xa increased phosphoinositide turnover in SMCs and when added to SMCs in culture was a potent mitogen. These effects were inhibited by DX9065 and by antibodies directed against EPR-1 and PDGF. Increased expression of EPR-1 was identified immunohistochemically on SMCs growing in culture and in SMCs from the rabbit carotid artery after vascular injury. When applied locally to air-injured rabbit carotid arteries, antibodies directed against EPR-1 (100 mug/ artery) strongly reduced myointimal proliferation 14 d after vascular injury (65-71% inhibition, P < 0.01). DX9065 (10 mg/kg, subcutaneous) inhibited myointimal proliferation significantly (43% inhibition, P < 0.05). These findings indicate that SMCs express functional high affinity receptors for factor Xa related to EPR-1, which may be of importance in the regulation of homeostasis of the vascular wall and after vascular injury.
Herbert
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J
Haemobiology Research Department, Sanofi Recherche, 31036 Toulouse, France. jean-marc.herbert@tls1.elfsanofi.fr
Bono
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Herault
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Avril
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Dol
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Mares
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Schaeffer
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D000818:Animals; D019138:Antibodies, Blocking / Q000276:immunology; D015153:Blotting, Western; D002339:Carotid Arteries / Q000166:cytology / Q000378:metabolism; D020212:Carotid Artery Injuries; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000293:injuries / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000378:metabolism; D005170:Factor X / Q000494:pharmacology; D015951:Factor Xa / Q000378:metabolism* / Q000494:pharmacology; D065427:Factor Xa Inhibitors; D006490:Hemostatics / Q000494:pharmacology; D006706:Homeostasis; D006801:Humans; D007150:Immunohistochemistry; D051034:Inhibitor of Apoptosis Proteins; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D010455:Peptides / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000276:immunology; D011422:Propionates / Q000494:pharmacology; D011485:Protein Binding; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors; D000077022:Survivin; D013917:Thrombin / Q000494:pharmacology
C086910:(2S)-2-(4-(((3S)-1-acetimidoyl-3-pyrrolidinyl)oxy)phenyl)-3-(7-amidino-2-naphtyl)propanoic acid; D019138:Antibodies, Blocking; C107489:BIRC5 protein, human; D065427:Factor Xa Inhibitors; D006490:Hemostatics; D051034:Inhibitor of Apoptosis Proteins; D009281:Naphthalenes; D010455:Peptides; D010716:Phosphatidylinositols; D010982:Platelet-Derived Growth Factor; D011422:Propionates; D011956:Receptors, Cell Surface; D015842:Serine Proteinase Inhibitors; D000077022:Survivin; D004815:Epidermal Growth Factor; D005170:Factor X; D013917:Thrombin; D015951:Factor Xa