To investigate the influence of the structure of heparin on its binding to vWF, we compared heparin fractions of different molecular weight (MW) or affinity for antithrombin III (ATIII). We studied the interaction of purified 125I-vWF or plasma vWF, labeled with a pool of 125I-monoclonal antibodies to vWF, with unfractionated heparin immobilized on agarose beads. Fractions were compared as competitors of these interactions and their effect was quantitated by their half-maximal inhibition (IC50). When the MW of the fractions decreased, especially below 7500, their IC50 increased, indicating that the affinity of the fractions for vWF decreased with their MW. Using heparin-derived oligosaccharides, we also demonstrated that a minimal chain length of 18 monosaccharides was required for heparin binding to vWF. In addition, different fractions with low affinity for ATIII were compared as competitors of 125-vWF binding to heparin-agarose. Despite a very low content of ATIII binding sites, some fractions retained a low IC50. Thus, heparin interaction with vWF is independent of the presence of the ATIII binding site and is mostly dependent on the length of the heparin chain. These data suggest that unfractionated heparin is a more potent inhibitor of vWF-dependent functions than low MW heparin fractions.
References
1
Ruggeri ZM,
Ware J.
The structure and function of von Willebrand factor. Thromb Haemostas 1992; 67: 594-9
2
Heremans A,
de Cock B,
Cassiman JJ,
van den Berghe H,
David G.
The core protein of the matrix-associated heparin sulfate proteoglycan binds to fibronectin. J Biol Chem 1990; 265: 8716-24
3
Fujimura Y,
Titani K,
Holland LZ,
Roberts JR,
Kostel P,
Ruggeri ZM,
Zimmerman TS.
A heparin-binding domain of human von Willebrand factor. J Biol Chem 1987; 262: 1734-9
4
Denis C,
Baruch D,
Kielty CM,
Ajzenberg N,
Christophe O,
Meyer D.
Localization of von Willebrand factor binding domains to endothelial extra-cellular matrix and to type VI collagen. Arterioscler and Thrombos 1993; 13: 398-406
5
Sobel M,
Me Neil PM,
Carlson PI,
Kermode JC,
Adelman B,
Conroy R,
Marques D.
Heparin inhibition of von Willebrand factor-dependent platelet function in vivo and in vitro. J Clin Invest 1991; 87: 1787-93
6
Fretto LJ,
Fowler WE,
Mc Caslin DR,
Erickson HP,
Mc Kee PA.
Substructure of human von Willebrand factor: proteolysis by V8 and characterization of two functional domains. J Biol Chem 1986; 261: 15679-89
7
Mohri H,
Yoshioka A,
Zimmerman TS,
Ruggeri ZM.
Isolation of the von Willebrand factor domain interacting with platelet glycoprotein lb, heparin and collagen and characterization of its three distinct functional sites. J Biol Chem 1989; 264: 17361-7
8
Sobel M,
Soler DF,
Kermode JC,
Harris RB.
Localization and characterization of a heparin binding domain peptide of human von Willebrand factor. J Biol Chem 1992; 267: 8857-62
9
Lindahl U,
Hook M,
Backstrom G,
Jacobsson I,
Riesenfeld J,
Malmstrom A,
Roden L,
Feingold DS.
Structure and biosynthesis of heparin-like polysaccharides. Fed Proc 1977; 36: 19-24
12
Choay J,
Petitou M,
Lormeau JC,
Synaï P,
Casu B,
Gatti G.
Structure activity relationship in heparin: A synthetic pentasaccharide with high affinity for antithrombin III and eliciting high anti-factor Xa activity. Biochem Biophys Res Comm 1983; 116: 492-9
13
Lane DA,
Denton J,
Flynn AM,
Thunberg L,
Lindahl U.
Anticoagulant activities of heparin oligosaccharides and their neutralization by platelet factor 4. Biochem J 1984; 218: 725-32
14
Höök M,
Björk I,
Hopwood J,
Lindahl U.
Anticoagulant activity of heparin: separation of high-activity and low-activity heparin species by affinity chromatography on immobilized antithrombin. FEBS Letter 1976; 66: 90-3
15
Schoen P,
Wielders S,
Petitou M,
Lindhout T.
The effect of sulfation on the anticoagulant and antithrombin Ill-binding properties of a heparin fraction with low affinity for Antithrombin III. Thromb Res 1990; 57: 415-23
17
Funahashi M,
Matsumoto I,
Seno N.
Preparation of three types of heparin-Sepharose and their binding activities to thrombin and antithrombin III. Anal Biochem 1982; 126: 414-21
20
Hoylaerts M,
Owen WG,
Collen D.
Involvement of heparin chain length in the heparin-catalyzed inhibition of thrombin by antithrombin III. J Biol Chem 1984; 259: 5670-7
21
Ogamo A,
Nagai A,
Nagasawa K.
Binding of heparin fractions and other polysulfated polysaccharides to plasma fibronectin: effects of molecular size and degree of sulfation of polysaccharides. Biochim Biophys Acta 1985; 841: 30-41
23
Lane DA,
Flynn AM,
Pejler G,
Lindahl U,
Choay J,
Preissner K.
Structural requirements for the neutralization of heparin-like saccharides by complement S protein/vitronectin. J Biol Chem 1987; 262: 16343-8
24
de Boer HC,
Preissner KT,
Bouma BN,
de Groot PG.
Binding of vitronectin-thrombin-antithrombin III complex to human endothelial cells is mediated by the heparin binding site of vitronectin. J Biol Chem 1992; 267: 2264-8
26
Bendetowicz AV,
Pacaud E,
Béguin S,
Uzan A,
Hemker HC.
On the relationship between molecular mass and anticoagulant activity in a low molecular weight heparin (Enoxaparin). Thromb Haemostas 1992; 66: 556-62
27
Hurst RE,
Poon MC,
Griffith MJ.
Structure-activity relationships of heparin. Independence of heparin charge density and antithrombin binding domains in thrombin inhibition by antithrombin and heparin cofactor II. J Clin Invest 1983; 72: 1042-5
28
Scott JP,
Montgomery RR,
Retzinger GS.
Dimeric ristocetin flocculates proteins, binds to platelets, and mediates von Willebrand factor-dependent agglutination of platelets. J Biol Chem 1991; 266: 8149-55
