scholarly journals Platelet adhesion to collagen in healthy volunteers is influenced by variation of both α2β1 density and von Willebrand factor

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1433-1437 ◽  
Author(s):  
Mark Roest ◽  
Jan J. Sixma ◽  
Ya-Ping Wu ◽  
Martin J. W. Ijsseldijk ◽  
Mariëlle Tempelman ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Normal Subjects ◽  
Collagen Type Iv ◽  
Collagen Types ◽  
Platelet Surface ◽  
Type Iv ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Platelet thrombus formation on collagen is initiated by platelet GPIb interaction with von Willebrand factor (vWF) bound to collagen, followed by firm attachment of the platelet to collagen by the integrin α2β1. Platelet and plasma vWF levels and α2β1 density on the platelet surface are highly variable among normal subjects; however, little is known about the consequences of this variability on platelet adhesion to collagen. A population of 32 normal subjects was studied to evaluate the relation between genetic and phenotypic variations of α2β1 density on the platelet surface, plasma vWF levels, platelet vWF levels, and adenosine diphosphate and adenosine triphosphate concentrations on the one hand and platelet adhesion to collagen under flow on the other hand. Platelet adhesion to collagen types I and III under flow was correlated with plasma levels of vWF (r2 = 0.45 and 0.42, respectively) and α2β1 density on the platelet surface (r2 = 0.35 and 0.17, not significant). Platelet adhesion to collagen type IV under flow was significantly correlated with platelet vWF levels (r2 = 0.34) and α2β1 density on the platelet surface (r2 = 0.42). Platelet adhesion to collagen types I and III depends on both plasma levels of vWF and α2β1 density on the platelet surface, whereas platelet adhesion to collagen type IV is mediated by both platelet vWF levels and α2β1 density on the platelet surface.

scholarly journals Platelet adhesion to collagen in healthy volunteers is influenced by variation of both α2β1 density and von Willebrand factor

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1433-1437 ◽  
Author(s):  
Mark Roest ◽  
Jan J. Sixma ◽  
Ya-Ping Wu ◽  
Martin J. W. Ijsseldijk ◽  
Mariëlle Tempelman ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Normal Subjects ◽  
Collagen Type Iv ◽  
Collagen Types ◽  
Platelet Surface ◽  
Type Iv ◽  
Von Willebrand ◽  
Willebrand Factor

Platelet thrombus formation on collagen is initiated by platelet GPIb interaction with von Willebrand factor (vWF) bound to collagen, followed by firm attachment of the platelet to collagen by the integrin α2β1. Platelet and plasma vWF levels and α2β1 density on the platelet surface are highly variable among normal subjects; however, little is known about the consequences of this variability on platelet adhesion to collagen. A population of 32 normal subjects was studied to evaluate the relation between genetic and phenotypic variations of α2β1 density on the platelet surface, plasma vWF levels, platelet vWF levels, and adenosine diphosphate and adenosine triphosphate concentrations on the one hand and platelet adhesion to collagen under flow on the other hand. Platelet adhesion to collagen types I and III under flow was correlated with plasma levels of vWF (r2 = 0.45 and 0.42, respectively) and α2β1 density on the platelet surface (r2 = 0.35 and 0.17, not significant). Platelet adhesion to collagen type IV under flow was significantly correlated with platelet vWF levels (r2 = 0.34) and α2β1 density on the platelet surface (r2 = 0.42). Platelet adhesion to collagen types I and III depends on both plasma levels of vWF and α2β1 density on the platelet surface, whereas platelet adhesion to collagen type IV is mediated by both platelet vWF levels and α2β1 density on the platelet surface.

Interventional Thermal Injury of the Arterial Wall: Unfolding of von Willebrand Factor and Its Increased Binding to Collagen after 55° C Heating

1996 ◽  
Vol 75 (03) ◽  
pp. 515-519 ◽  
Author(s):  
Mark J Post ◽  
Anke N de Graaf-Bos ◽  
George Posthuma ◽  
Philip G de Groot ◽  
Jan J Sixma ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Conformational Changes ◽  
Arterial Wall ◽  
Platelet Adhesion ◽  
Type I ◽  
Temperature Dependent ◽  
Collagen Types ◽  
Electron Microscopic ◽  
Von Willebrand ◽  
Willebrand Factor

Summary Purpose. Thermal angioplasty alters the thrombogenicity of the arterial wall. In previous studies, platelet adhesion was found to increase after heating human subendothelium to 55° C and decrease after heating to 90° C. In the present electron microscopic study, the mechanism of this temperature-dependent platelet adhesion to the heated arterial wall is elucidated by investigating temperature-dependent conformational changes of von Willebrand factor (vWF) and collagen types I and III and the binding of vWF to heated collagen. Methods. Purified vWF and/or collagen was applied to electron microscopic grids and heated by floating on a salt-solution of 37° C, 55° C or 90° C for 15 s. After incubation with a polyclonal antibody against vWF and incubation with protein A/gold, the grids were examined by electron microscopy. Results. At 37° C, vWF was coiled. At 55° C, vWF unfolded, whereas heating at 90° C caused a reduction in antigenicity. Collagen fibers heated to 37° C were 60.3 ± 3.1 nm wide. Heating to 55° C resulted in the unwinding of the fibers, increasing the width to 87.5 ± 8.2 nm (p < 0.01). Heating to 90° C resulted in denatured fibers with an enlarged width of 85.1 ± 6.1 nm (p < 0.05). Heating of collagen to 55° C resulted in an increased vWF binding as compared to collagen heated to 37° C or to 90° C. Incubation of collagen with vWF, prior to heating, resulted in a vWF binding after heating to 55° C that was similar to the 37° C binding and a decreased binding after 90° C. Conclusions. After 55° C heating, the von Willebrand factor molecule unfolds and collagen types I and III exhibit an increased adhesiveness for von Willebrand factor. Heating to 90° C denatures von Willebrand factor and collagen. The conformation changes of von Willebrand factor and its altered binding to collagen type I and III may explain the increased and decreased platelet adhesion to subendothelium after 55° C and 90° C heating, respectively.

PRIMARY BINDING SITE OF VON WILLEBRAND FACTOR IN THE SUBENDOTHELIUM WHICH MEDIATES PLATELET ADHESION IS NOT COLLAGEN

1987 ◽  
Author(s):  
Philip G de Groot ◽  
Jan A van Mourik ◽  
Jan J Sixma
Keyword(s):  
Monoclonal Antibody ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Collagen Type I ◽  
Extracellular Matrices ◽  
Type I ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

We have studies the binding of von Willebrand factor (vWF) to extracellular matrices of endothelial cells and smooth muscle cells and to the vessel wall of human umbilical arteries in relation to its function in supporting platelet adhesion at high shear rates. CLB-RAg 38, a monoclonal antibody directed against vWF inhibits the binding of 125I-vWF extracellular matrices completely. The binding of 125I-vWF to subendothelium is not inhibited, because there are many different binding sites. CLB-RAg 38 inhibits platelet adhesion to extracellular matrices and subendothelium, in sofar as it is dependent on plasma vWF. CLB-RAg 38 has no effect on adhesion depending on vWF already bound to the matrix or subendothelium. CLB-RAg 38 does not inhibit binding of vWF to collagen type I and type III. Another monoclonal antibody against vWF, CLB-RAg 201, completely inhibits binding of vWF to collagen type I and type III. CLB-RAg 201 does not inhibit binding of 125I-vWF ot the extracellular matrices. CLB-RAg 201 partly inhibits platelet adhesion but this inhibition is also present when the adhesion depends on vWF already present in matrix or subendothelium, indicating that CLB-RAg 201 also inhibits the adhesion of platelets directly, this in contrast to CLB-RAg 38. The epitopes for CLB-RAg 201 and 38 were found on different tryptic fragments of vWF. These data indicate that vWF binds to subendothelium and to matrices of cultured cells by mechanism that is different from binding to collagen.

scholarly journals Platelet adhesion involves a novel interaction between vimentin and von Willebrand factor under high shear stress

Blood ◽  
2014 ◽  
Vol 123 (17) ◽  
pp. 2715-2721 ◽  
Author(s):  
Qi Da ◽  
Molly Behymer ◽  
Juliana I. Correa ◽  
K. Vinod Vijayan ◽  
Miguel A. Cruz
Keyword(s):  
Shear Stress ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
High Shear ◽  
High Shear Stress ◽  
Platelet Surface ◽  
Key Points ◽  
Von Willebrand ◽  
Willebrand Factor

Key Points Vimentin expressed on the platelet surface serves as adhesive receptor for VWF.

scholarly journals Platelet Adhesion to Multimeric and Dimeric von Willebrand Factor and to Collagen Type III Preincubated With von Willebrand Factor

1996 ◽  
Vol 16 (5) ◽  
pp. 611-620 ◽  
Author(s):  
Ya-Ping Wu ◽  
Hans H.F.I. van Breugel ◽  
Hanneke Lankhof ◽  
Robert J. Wise ◽  
Robert I. Handin ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Collagen Type Iii ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

Mutations in the von Willebrand Factor A1 Domain That Increase the Affinity for Collagen Have Different Effects on the Binding to Glycoprotein Ib.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3661-3661
Author(s):  
Miguel A. Cruz ◽  
Liza D. Morales
Keyword(s):  
Binding Site ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Type I ◽  
Fibrillar Collagen ◽  
Wild Type ◽  
Collagen Types ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The interaction of plasma von Willebrand factor (VWF) with collagen at the site of vascular injury plays a critical role in the initiation of thrombus formation under high shear stress. It does this by forming a bridge between the fibrils of collagen in the subendothelium and the platelet glycoprotein Ib-IX-V complex (GPIb). The A1 domain of VWF is the binding site for GPIb whereas the collagen-function of VWF is controlled by both A1 and A3 domains. The VWF-A3 domain is important to support binding to fibrils of collagen Types I and III while the A1 domain is involved in the binding to microfibrillar collagen Type VI. It is assumed that the interaction of VWF with fibrillar collagen (via the A3 domain) may regulate the expression of the GPIb-binding site in the A1 domain. However, there is no a definite data to substantiate that hypothesis. Our goal was to demonstrate that a direct interaction between the A1 domain and fibrillar collagen Types I or III exposes the GPIb binding site. Thus, we postulated that platelet GPIb is able to interact with isolated A1 domain that is bound to collagen. We have demonstrated that the VWF-A1 protein binds specifically to human placenta collagen Types I and III with a KD ~ 200 nM by using surface plasmon resonance (SPR). Using plasma-free blood, we have provided strong evidence that isolated VWF-A1 domain bound to either collagen Type I or III is able to support platelet adhesion under high flow conditions. This platelet interaction was effectively blocked with antibodies against either GPIb or A1 domain. These results clearly show the ability of the A1 domain to concurrently interact with both GPIb and collagen fibrils and they also suggest that the collagen-A1 binding may regulate the expression of the GPIb-binding site in the A1 domain. To test this hypothesis, we analyzed three residues that in a previous mutagenesis study they increased the binding of VWF to GPIb, reasoning that they may have an effect on the collagen binding activity as well. The three residues are located in the a7 helix (rear face) of the folded A1 domain and mutagenesis studies of other I(A)-domains have demonstrated that this helix plays a role in regulating the affinity of the ligand-binding. We introduced point mutations into the 3 residues and the recombinant mutant proteins were expressed in bacteria. The three mutants (R687E, D688R, and E689R) were purified as wild type and their structural integrity was confirmed with three conformation-specific antibodies. All the mutants bound to both collagens Type I or III with an affinity much higher than the wild type (WT) (KD~ 9 -1 nM). The mutants were assessed by their ability to mediate platelet adhesion to collagen, and their ability to inhibit both ristocetin-induced platelet agglutination and shear-induced platelet aggregation. Interestingly, in the three assays the R687E mutant had an activity higher than WT while the D688R had a markedly decrease activity. The mutant E689R had an activity similar to that of WT for the three assays. Together our data indicate that a direct association between the VWF-A1 domain and collagen fibrils influences the expression of GPIb binding function in VWF. Further, these data indicate that residue R687 located in the a7 helix plays a novel and important role in modulating the collagen/A1/GPIb binding.

A3 Domain Is Essential for Interaction of von Willebrand Factor with Collagen Type III

1996 ◽  
Vol 75 (06) ◽  
pp. 950-958 ◽  
Author(s):  
Hanneke L Lankhof ◽  
Maggy van Hoeij ◽  
Marion E Schiphorst ◽  
Madelon Bracke ◽  
Ya-Ping Wu ◽  
...  
Keyword(s):  
Binding Site ◽  
Von Willebrand Factor ◽  
Binding Sites ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Collagen Type Iii ◽  
Collagen Binding ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

Summaryvon Willebrand factor (vWF) mediates platelet adhesion at sites of vascular damage. It acts as a bridge between receptors on platelets and collagens present in the connective tissue. Two collagen binding sites have been identified on the A1 and A3 domain of the vWF subunit. To study the functional importance of these binding sites, we have made two deletion mutants that lack the A1 domain (residues 478-716; ΔA1-vWF; Sixma et al. Eur. J. Biochem. 196,369,1991 [1]) or the A3 domain (residues 910-1113; ΔA3-vWF). After transfection in baby hamster kidney cells overexpressing furin, the mutants were processed and secreted efficiently. Ristocetin or botrocetin induced platelet binding was normal for ΔA3-vWF as was binding to heparin and factor VIII. As reported by Sixma et al. (1) ΔAl-vWF still binds to collagen type III, indicating that the A3 domain is sufficient for the interaction. In the current study, we investigated the binding of ΔA3-vWF to collagen type III. When preincubated on collagen type III it did not support platelet adhesion under flow conditions, whereas it was able to support platelet adhesion when coated directly to a glass surface. The binding of 125I-ΔA3-vWF to collagen was specific but maximal binding was about 40 times less compared to 125I-vWF. When added at 25 times excess, ΔA3-vWF did not compete with 125I-vWF for binding to collagen type III, whereas ΔAl-vWF did. The binding of 125I-ΔA3-vWF could be blocked by excess unlabeled vWF but not by ΔA1-vWF. In conclusion, we demonstrate that the A3 domain in vWF contains the major collagen binding site. The major binding site present on the A3 domain and the minor site present on A1 bind to different sites on collagen.

scholarly journals Functional Studies on Platelet Adhesion With Recombinant von Willebrand Factor Type 2B Mutants R543Q and R543W Under Conditions of Flow

Blood ◽  
1997 ◽  
Vol 89 (8) ◽  
pp. 2766-2772 ◽  
Author(s):  
Hanneke Lankhof ◽  
Conchi Damas ◽  
Marion E. Schiphorst ◽  
Martin J.W. IJsseldijk ◽  
Madelon Bracke ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Cell Culture Supernatant ◽  
Collagen Type Iii ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Type 2B von Willebrand disease (vWD) is characterized by the absence of the very high molecular weight von Willebrand factor (vWF ) multimers from plasma, which is caused by spontaneous binding to platelet receptor glycoprotein Ib (GPIb). We studied two mutations in the A1 domain at position 543 in which arginine (R) was replaced by glutamine (Q) or tryptophan (W), respectively. Both mutations were previously identified in vWD type 2B patients. The mutations R543Q and R543W were cloned into a eukaryotic expression vector and subsequently transfected in baby hamster kidney cells overexpressing furin (fur-BHK). Stable cell lines were established by which the mutants were secreted in the cell culture supernatant. The subunit composition and multimeric structure of R543Q and R543W were similar to wild-type (WT) vWF. The mutants showed a spontaneous binding to GPIb. R543Q and R543W showed normal binding to collagen type III or heparin. Both mutants supported platelet adhesion under conditions of flow, usually when preincubated on a collagen type III surface. A low dose (2.5% of the concentration present in normal pooled plasma) of recombinant R543Q or R543W added to normal whole blood inhibited platelet adhesion to collagen type III. No inhibition was found when vWF was used as an adhesive surface. These results indicate that point mutations identified in vWD type 2B cause bleeding symptoms by two mechanisms: (1) the mutants cause platelet aggregation, which in vivo is followed by removal of the aggregates leading to the loss of high molecular weight multimers and thrombocytopenia, (2) on binding to circulating platelets the mutants block platelet adhesion. Relatively few molecules are required for the latter effect.

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