scholarly journals Expressed full-length von Willebrand factor containing missense mutations linked to type IIB von Willebrand disease shows enhanced binding to platelets

Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2048-2055 ◽  
Author(s):  
PA Kroner ◽  
ML Kluessendorf ◽  
JP Scott ◽  
RR Montgomery
Keyword(s):  
Von Willebrand Factor ◽  
Messenger Rna ◽  
Von Willebrand Disease ◽  
Full Length ◽  
Platelet Glycoprotein ◽  
Missense Mutations ◽  
Mutant Proteins ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract von Willebrand disease (vWD) variant type IIB is an inherited bleeding disorder resulting from the spontaneous binding of defective von Willebrand factor (vWF) to platelets in vivo. To identify the molecular basis for type IIB vWD, we used reverse transcription and the polymerase chain reaction to examine the nucleotide sequence of the platelet glycoprotein (GP) Ib-binding domain encoded by the vWF messenger RNA in an affected family, and in an unrelated affected individual. We identified two different missense mutations linked with expression of type IIB vWD. These mutations, which lead to Pro574---- Leu and Val553----Met substitutions, respectively, were each introduced into the full-length vWF expression vector pvW198, and both wild-type (wt) and mutant vWF were transiently expressed in COS-7 cells. Binding assays showed that both mutant proteins showed significant non- ristocetin-dependent spontaneous binding to platelets, and that complete binding was induced by low concentrations of ristocetin that failed to induce platelet binding by wt vWF. The vWF/platelet interaction was inhibited by the anti-vWF monoclonal antibody (MoAb) AvW3, and the anti-GPIb MoAb AP1, which both block vWF binding to platelets. These results show that the identified missense mutations are the likely basis for the expression of type IIB vWD in these affected individuals.

scholarly journals Expressed full-length von Willebrand factor containing missense mutations linked to type IIB von Willebrand disease shows enhanced binding to platelets

Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2048-2055 ◽  
Author(s):  
PA Kroner ◽  
ML Kluessendorf ◽  
JP Scott ◽  
RR Montgomery
Keyword(s):  
Von Willebrand Factor ◽  
Messenger Rna ◽  
Von Willebrand Disease ◽  
Full Length ◽  
Platelet Glycoprotein ◽  
Missense Mutations ◽  
Mutant Proteins ◽  
Von Willebrand ◽  
Willebrand Factor

von Willebrand disease (vWD) variant type IIB is an inherited bleeding disorder resulting from the spontaneous binding of defective von Willebrand factor (vWF) to platelets in vivo. To identify the molecular basis for type IIB vWD, we used reverse transcription and the polymerase chain reaction to examine the nucleotide sequence of the platelet glycoprotein (GP) Ib-binding domain encoded by the vWF messenger RNA in an affected family, and in an unrelated affected individual. We identified two different missense mutations linked with expression of type IIB vWD. These mutations, which lead to Pro574---- Leu and Val553----Met substitutions, respectively, were each introduced into the full-length vWF expression vector pvW198, and both wild-type (wt) and mutant vWF were transiently expressed in COS-7 cells. Binding assays showed that both mutant proteins showed significant non- ristocetin-dependent spontaneous binding to platelets, and that complete binding was induced by low concentrations of ristocetin that failed to induce platelet binding by wt vWF. The vWF/platelet interaction was inhibited by the anti-vWF monoclonal antibody (MoAb) AvW3, and the anti-GPIb MoAb AP1, which both block vWF binding to platelets. These results show that the identified missense mutations are the likely basis for the expression of type IIB vWD in these affected individuals.

scholarly journals Clearance of von Willebrand factor

2008 ◽  
Vol 99 (02) ◽  
pp. 271-278 ◽  
Author(s):  
Olivier D. Christophe ◽  
Beatrijs D. Oortwijn ◽  
Peter J. Lenting ◽  
Cécile V. Denis
Keyword(s):  
Von Willebrand Factor ◽  
Half Life ◽  
Von Willebrand Disease ◽  
In Vivo Studies ◽  
Missense Mutations ◽  
Common Component ◽  
Starting Point ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryThe life cycle of von Willebrand factor (VWF) comprises a number of distinct steps, ranging from the controlled expression of theVWF gene in endothelial cells and megakaryocytes to the removal of VWF from the circulation. The various aspects of VWF clearance have been the objects of intense research in the last few years, stimulated by observations thatVWF clearance is a relatively common component of the pathogenesis of type 1 von Willebrand disease (VWD). Moreover, improving the survival of VWF is now considered as a viable therapeutic strategy to prolong the half-life of factor VIII in order to optimise treatment of haemophilia A. The present review aims to provide an overview of recent findings with regard to the molecular basis of VWF clearance. A number of parameters have been identified that influence VWF clearance, including its glycosylation profile and a number of VWF missense mutations. In addition, in-vivo studies have been used to identify cells that contribute to the catabolism of VWF, providing a starting point for the identification of receptors that mediate the cellular uptake ofVWF.Finally, we discuss recent data describing chemically modification of VWF as an approach to prolong the half-life of the VWF/FVIII complex.

Effect of Type IIB von Willebrand Disease Mutation Arg(545)Cys on Platelet Glycoprotein Ib Binding – Studies with Recombinant von Willebrand Factor

1993 ◽  
Vol 70 (06) ◽  
pp. 1058-1062 ◽  
Author(s):  
Aida Inbal ◽  
Nurit Kornbrot ◽  
Paul Harrison ◽  
Anna M Randi ◽  
J Evan Sadler
Keyword(s):  
Molecular Weight ◽  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Missense Mutations ◽  
Wild Type ◽  
Binding Studies ◽  
Function Type ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryType IIB von Willebrand disease (vWD) is characterized by a selective loss of high molecular weight von Willebrand factor (vWF) multimers in plasma due to their abnormally enhanced reactivity with platelets. Several missense mutations in the platelet glycoprotein lb (GPIb) binding domain of vWF were recently characterized that cause type IIB vWD. The effect of type IIB mutation Arg(545)Cys on vWF binding to platelet GPIb was studied using recombinant wild type (rvWFWT) and mutant rvWFR545C expressed in COS-7 cells. In the absence of ristocetin, 50% of rvWFR545C bound spontaneously to platelet GPIb and the binding increased to 70% in the presence of 0.2 mg/ml ristocetin; rvWFWT did not bind significantly under either condition. Botrocetin-induced binding of rvWFR545C was only slightly increased compared to rvWFWT. These data demonstrate that the Arg(545)Cys mutation increases the affinity of vWF for GPIb, resulting in the characteristic gain-of-function type IIB vWD phenotype.

scholarly journals Visualizing the von Willebrand factor/glycoprotein Ib-IX axis with a platelet-type von Willebrand disease mutation

Blood ◽  
2009 ◽  
Vol 114 (27) ◽  
pp. 5541-5546 ◽  
Author(s):  
Jose A. Guerrero ◽  
Mark Kyei ◽  
Susan Russell ◽  
Junling Liu ◽  
T. Kent Gartner ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Thrombus Formation ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Ligand Interaction ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractPlatelet-type von Willebrand disease (PT-VWD) is a bleeding disorder of the platelet glycoprotein Ib-IX/von Willebrand factor (VWF) axis caused by mutations in the glycoprotein Ib-IX receptor that lead to an increased affinity with VWF. In this report, platelets from a mouse expressing a mutation associated with PT-VWD have been visualized using state-of-the art image collection and processing. Confocal analysis revealed that VWF bound to the surface of single platelets and bridging micro-aggregates of platelets. Surface-bound VWF appears as a large, linear structure on the surface of 50% of the PT-VWD platelets. In vivo thrombus formation after chemical injury to the carotid artery revealed a severe impairment to occlusion as a consequence of the PT-VWD mutation. In vitro stimulation of PT-VWD platelets with adenosine diphosphate or thrombin demonstrates a significant block in their ability to bind fibrinogen. The impairment of in vivo thrombus formation and in vitro fibrinogen binding are more significant than might be expected from the observed platelet binding to VWF polymers over a small portion of the plasma membrane. Visualization of the receptor/ligand interaction and characterization of a severe antithrombotic phenotype provide a new understanding on the molecular basis of bleeding associated with the PT-VWD phenotype.

The Anti Von Willebrand Factor Aptamer ARC1779 Prevents the Desmopressin-Induced Thrombocytopenia in VWD Type 2B.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3374-3374
Author(s):  
Petra Paulinska ◽  
Bernd Jilma ◽  
Christa Firbas ◽  
Robert G Schaub ◽  
James C. Gilbert ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Double Blind ◽  
Platelet Counts ◽  
Multiple Blood ◽  
Pre Treatment ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Introduction: Von Willebrand Disease (VWD) Type 2B is characterized by increased affinity of VWF for the platelet glycoprotein receptor Ib (GPIb). Consequently, infusion of desmopressin, a standard of treatment for other forms of VWD, causes transient thrombocytopenia in patients with VWD-2B. The aim of the study was to test whether the novel anti-VWF aptamer ARC1779, which inhibits the interaction of VWF with GPIb, could abrogate the transient desmopressin-induced thrombocytopenia in VWD-2B. Patients and Methods: This was part of a clinical trial using a double-blind, randomized, placebo-controlled, crossover design. A patient with VWD 2B received desmopressin (0.4 mcg/kg) alone, or desmopressin after pre-treatment with ARC1779 targeted to a plasma concentration of 10 mcg/mL. Multiple blood samples were obtained over 24 hours to measure von Willebrand Factor Antigen, Ristocetin Cofactor (RiCO), FVIII activity and multimers. Results: Desmopressin alone (open circles) increased VWF:Ag by 38% (not shown), and VWF:RiCo 3.4-fold within 30 min, and profoundly decreased platelet counts by 87%. In striking contrast, ARC1779 (solid triangles) completely prevented the desmopressin induced fall in platelet counts (Figure), although the increase in vWF:Ag and vWF:RiCO was greater (2.7-fold and 12-fold, respectively). Conclusions: This randomized, double-blind, placebo-controlled experiment shows that ARC1779 effectively prevents consumption of VWF and platelets in response to desmopressin in VWD Type 2B. It provides in vivo proof of concept that ARC1779 is a potent inhibitor of the VWF A1 domain interaction with GPIb. Figure Figure

Platelet Activation and Aggregation Induced by Recombinant von Willebrand Factors Reproducing Four Type 2B von Willebrand Disease Missense Mutations

1998 ◽  
Vol 79 (01) ◽  
pp. 211-216 ◽  
Author(s):  
Lysiane Hilbert ◽  
Claudine Mazurier ◽  
Christophe de Romeuf
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Missense Mutations ◽  
Inhibit Platelet Aggregation ◽  
Wild Type ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryType 2B of von Willebrand disease (vWD) refers to qualitative variants with increased affinity of von Willebrand factor (vWF) for platelet glycoprotein Ib (GPIb). All the mutations responsible for type 2B vWD have been located in the A1 domain of vWF. In this study, various recombinant von Willebrand factors (rvWF) reproducing four type 2B vWD missense mutations were compared to wild-type rvWF (WT-rvWF) for their spontaneous binding to platelets and their capacity to induce platelet activation and aggregation. Our data show that the multimeric pattern of each mutated rvWF is similar to that of WT-rvWF but the extent of spontaneous binding and the capacity to induce platelet activation and aggregation are more important for the R543Q and V553M mutations than for the L697V and A698V mutations. Both the binding of mutated rvWFs to platelets and platelet aggregation induced by type 2B rvWFs are inhibited by monoclonal anti-GPIb and anti-vWF antibodies, inhibitors of vWF binding to platelets in the presence of ristocetin, as well as by aurin tricarboxylic acid. On the other hand, EDTA and a monoclonal antibody directed against GPIIb/IIIa only inhibit platelet aggregation. Furthermore, the incubation of type 2B rvWFs with platelets, under stirring conditions, results in the decrease in high molecular weight vWF multimers in solution, the extent of which appears correlated with that of plasma vWF from type 2B vWD patients harboring the corresponding missense mutation. This study supports that the binding of different mutated type 2B vWFs onto platelet GPIb induces various degrees of platelet activation and aggregation and thus suggests that the phenotypic heterogeneity of type 2B vWD may be related to the nature and/or location of the causative point mutation.

The Interaction of Botrocetin with Normal or Variant von Willebrand Factor (Types IIA and IIB) and Its Inhibition by Monoclonal Antibodies that Block Receptor Binding

1992 ◽  
Vol 68 (04) ◽  
pp. 464-469 ◽  
Author(s):  
Y Fujimura ◽  
S Miyata ◽  
S Nishida ◽  
S Miura ◽  
M Kaneda ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Von Willebrand Factor ◽  
Binding Activity ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Normal Individuals ◽  
Rag 1 ◽  
The One ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryWe have recently shown the existence of two distinct forms of botrocetin (one-chain and two-chain), and demonstrated that the two-chain species is approximately 30 times more active than the one-chain in promoting von Willebrand factor (vWF) binding to platelet glycoprotein (GP) Ib. The N-terminal sequence of two-chain botrocetin is highly homologous to sea-urchin Echinoidin and other Ca2+-dependent lectins (Fujimura et al., Biochemistry 1991; 30: 1957–64).Present data indicate that purified two-chain botrocetin binds to vWF from plasmas of patients with type IIA or IIB von Willebrand disease and its interaction is indistinguishable from that with vWF from normal individuals. However, an “activated complex” formed between botrocetin and IIB vWF expresses an enhanced biological activity for binding to GP Ib whereas the complex with IIA vWF has a decreased binding activity. Among several anti-vWF monoclonal antibodies (MoAbs) which inhibit ristocetin-induced platelet aggregation and/or vWF binding to GPIb, only two MoAbs (NMC-4 and RFF-VIII RAG:1) abolished direct binding between purified botrocetin and vWF. This suggests that they recognize an epitope(s) on the vWF molecule in close proximity to the botrocetin binding site.

scholarly journals The von willebrand factor domain-mediating botrocetin-induced binding to glycoprotein IB lies between Val449 and Lys728

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 985-988 ◽  
Author(s):  
Y Fujimura ◽  
LZ Holland ◽  
ZM Ruggeri ◽  
TS Zimmerman
Keyword(s):  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Von Willebrand Factor ◽  
Amino Acid Residue ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Tryptic Fragment ◽  
Alternative Agent ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Botrocetin, a component of Bothrops jararaca venom, induces von Willebrand factor (vWF)-dependent platelet agglutination and has been proposed as an alternative agent to ristocetin for evaluating vWF function. However, important differences between the vWF-platelet interactions induced by these two agents have suggested that different regions of vWF and the platelet may be involved in the interactions induced by the two agonists. We have recently demonstrated that binding of vWF to the platelet glycoprotein (GP) Ib receptor, either induced by ristocetin or as occurs spontaneously with asialo-vWF or vWF from IIb von Willebrand disease, is mediated by a domain residing on a 52/48- kilodalton (kD) tryptic fragment of vWF. This fragment extends from amino acid residue Val (449) to Lys (728). We have now found that this 52/48-kD fragment blocks botrocetin-induced binding of vWF to platelets and completely inhibits botrocetin-induced platelet agglutination. These results provide evidence that the vWF domain-mediating, botrocetin-induced platelet agglutination lies within the region delimited by this fragment and is therefore close to or identical with that which mediates ristocetin-induced binding and spontaneous binding of vWF to platelet GPIb. Anti-GPIb monoclonal antibodies also blocked agglutination, which showed that botrocetin, like ristocetin, induces binding of vWF to the GPIb receptor.

VON WILLEBRAND FACTOR (VWF) ANTIGENS IN URINE

1987 ◽  
Author(s):  
A M V Silveira ◽  
B Hessel ◽  
B Blombäck
Keyword(s):  
Monoclonal Antibodies ◽  
Von Willebrand Factor ◽  
High Performance ◽  
Molecular Size ◽  
Von Willebrand Disease ◽  
Enzyme Linked Immunosorbent Assay ◽  
Normal Urine ◽  
Von Willebrand ◽  
Willebrand Factor

Human urine was analyzed using a sensitive enzyme linked immunosorbent assay (ELISA) for von Willebrand factor (VWF) antigen. Urine of healthy persons contained VWF immunoreactivity. In the urine of a patient with severe von Willebrand disease, the VWF antigen was only detectable after intravenous infusion of VWF-Factor VIII concentrate. The VWF antigen in normal urine was analyzed by gel permeation high performance liquid chromatography (HPLC) and gel electrophoresis combined with immunoblotting. These analyses revealed three immunoreactive components of Mr 350 kDa, 60 kDa, and 20 kDa, respectively, the 60 kDa being the major component. Monoclonal antibodies of known specificity to VWF molecule were used in ELISA and immunoblotting to analyze urinary VWF. The three components reacted with an antibody to the central part of VWF, which is called fragment I, and contains the binding site for collagen. No significant immunoreac-tion was observed with monoclonal antibodies to the Nor C-terminal portions of VWF.VWF derivatives of molecular size similar to the largest urinary antigens were also observed in normal plasma. However, there is not an obvious relationship between these plasma forms and the products in urine since reduction of plasma and urine yields different products.These results indicate that VWF antigens excreted in normal urine are most likely fragments of VWF produced by limited degradation in vivo. This degradation preserves the central part of VWF molecule, the one which reacts with the antibody that blocks the binding of VWF to collagen.

scholarly journals Influence of mutations and size of multimers in type II von Willebrand disease upon the function of von Willebrand factor

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3553-3561 ◽  
Author(s):  
O Christophe ◽  
AS Ribba ◽  
D Baruch ◽  
B Obert ◽  
C Rouault ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Point Mutations ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Binding Assays ◽  
Normal Individuals ◽  
Binding Isotherms ◽  
Significant Difference ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract We compared the properties of plasma von Willebrand factor (vWF) from normal individuals and from two patients with type IIA (Glu875Lys) and type IIB (duplication of Met 540) von Willebrand disease (vWD) with the corresponding fully multimerized recombinant proteins. We included cryosupernatant from normal human plasma and type IIA plasma (Cys509Arg). Functions of vWF were analyzed by binding assays to platelets in the presence of ristocetin or botrocetin. Parameters of binding (number of binding sites per vWF subunit, and dissociation constant Kd) were quantitatively estimated from the binding isotherms of 125I-botrocetin or glycocalicin to vWF, independently of the size of the multimers. We found that ristocetin- or botrocetin-induced binding to platelets was correlated in all cases with the size of vWF multimers. In the absence of inducer, only type IIB rvWF Met-Met540 spontaneously bound to platelets. No significant difference of binding of purified botrocetin to vWF was found between normal and patients' plasma, or between wild-type rvWF (rvWF-WT) and rvWF-Lys875. In contrast, affinity of botrocetin for type IIB rvWF Met-Met540 was decreased. Botrocetin-induced binding of glycocalicin to vWF from all plasma and cryosupernatant was similar. Compared with rvWF-WT, binding of glycocalicin to rvWF-Lys875 was normal. In contrast, the affinity for type IIB rvWF Met-Met540 was 10-fold greater. Thus, our data suggest that, in the patients tested, the abnormal IIA phenotype results from the lack of large-sized multimers and is independent of the point mutations. In contrast, the type IIB mutation is directly involved by providing a conformation to the vWF subunits that allows the high molecular weight multimers to spontaneously interact with platelet glycoprotein Ib.

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