Characterization of a novel mutation in the von Willebrand factor propeptide in a distinct subtype of recessive von Willebrand disease

2008 ◽  
Vol 100 (08) ◽  
pp. 211-216 ◽  
Author(s):  
Elsa Lanke ◽  
Ann-Charlotte Kristoffersson ◽  
Malou Philips ◽  
Lars Holmberg ◽  
Stefan Lethagen

SummaryvonWillebrand factor (VWF) is a plasma protein that consists of a series of multimers of which the high-molecular-weight VWF multimers are the most potent in platelet adhesion and aggre-gation. The propeptide of theVWF (VWFpp) is known to be essential in the process of multimer assembly. Genetic studies were performed in a patient with a phenotype of vonWillebrand disease (VWD) characterized by very low plasma factorVIII and VWF levels and a VWF consisting of only a dimeric band and total absence of all multimers in plasma. The patient was found to be homozygous for the novel C570S mutation, caused by a 1709G>C transition in exon 14 of theVWF gene coding for the propeptide. Three asymptomatic relatives were found to be heterozygous. In-vitro mutagenesis and expression in COS-7 cells confirmed the detrimental effect of the mutation on VWF multimerization. Our findings show that the C570S mutation in the VWFpp abolishes multimerization of VWF. The mutation probably disrupts the normal configuration of the VWFpp, which is essential for correct orientation of the protomers and ultimately multimerization. The mutant amino acid is located in a region that is highly conserved across several species which underlines its critical role. This variant constitutes a distinct subtype of recessive 2AVWD with the exclusive presence of the dimeric form of VWF in plasma.

1998 ◽  
Vol 79 (04) ◽  
pp. 718-722 ◽  
Author(s):  
D. Karpman ◽  
C. Isaksson ◽  
A. C. Kristoffersson ◽  
S. Lethagen ◽  
R. Schneppenheim ◽  
...  

SummaryThe molecular defects of the von Willebrand factor (vWF) have been studied in the patient in whom the von Willebrand disease phenotype IIC was originally described. A six nucleotide insert, AATCCC, was found in exon 11 of the vWF gene, predicting the insertion of the amino acids asparagine and proline between phenylala-nine 404 and threonine 405 of the vWF propeptide. The mutation was present in one allele. Analysis of amplification products derived from platelet vWF mRNA showed the other allele to be silent. The patient is thus a compound heterozygote for a null allele and the IIC allele, in accord with the recessive mode of inheritance of the IIC phenotype. Family studies indicated the IIC mutation to have occurred de novo, possibly as a result of a duplication event. In vitro mutagenesis and expression in COS-7 cells confirmed the detrimental effect of the mutation on vWF multimer assembly. Taken together with those of earlier studies the present findings suggest that the IIC phenotype may well be exclusively caused by mutations which result in changes of the amino acid sequence in certain regions of the vWF propeptide. Although in the recently revised classification of von Willebrand’s disease variants, the IIC type is included in the 2A category, obviously it constitutes a very distinct subtype.


Blood ◽  
2001 ◽  
Vol 97 (4) ◽  
pp. 952-959 ◽  
Author(s):  
Anne-Sophie Ribba ◽  
Lysiane Hilbert ◽  
Jean-Maurice Lavergne ◽  
Edith Fressinaud ◽  
Catherine Boyer-Neumann ◽  
...  

Abstract The study identified 10 patients from 6 families with prolonged bleeding time, decreased von Willebrand factor (vWF) ristocetin cofactor activity (RCoF) to vWF:Ag (antigen) ratio, and reduced ristocetin-induced platelet agglutination as well as ristocetin- or botrocetin-induced binding of plasma vWF to platelet glycoprotein Ib (GpIb). In addition, all patients showed a decrease of intermediate-molecular-weight (intermediate-MW) and high-molecular-weight (HMW) multimers of vWF. In the heterozygous state, a cysteine-to-threonine (C → T) transversion was detected at nucleotide 4193 of the VWF gene of all patients and lead to the arginine (R)522C substitution in the A1 loop of vWF mature subunit (R1315C in the preprovWF). By in vitro mutagenesis of full-length complementary DNA (cDNA) of vWF and transient expression in COS-7 cells, the mutated C552 recombinant vWF (C552rvWF) was found to exhibit decreased expression, abnormal folding, and lack of intermediate-MW and HMW multimers. In addition, direct binding of botrocetin to C552rvWF, as well as ristocetin- and botrocetin-induced binding of C552rvWF to GpIb, was markedly decreased. Although being localized in an area of the A1 loop of vWF where most of the type 2B mutations that induce a gain-of-function have been identified, the R552C mutation induces a 2A-like phenotype with a decrease of intermediate-MW and HMW multimers as well as a loss-of-function of vWF in the presence of either ristocetin or botrocetin.


1996 ◽  
Vol 76 (02) ◽  
pp. 253-257 ◽  
Author(s):  
Takeshi Hagiwara ◽  
Hiroshi Inaba ◽  
Shinichi Yoshida ◽  
Keiko Nagaizumi ◽  
Morio Arai ◽  
...  

SummaryGenetic materials from 16 unrelated Japanese patients with von Willebrand disease (vWD) were analyzed for mutations. Exon 28 of the von Willebrand factor (vWF) gene, where point mutations have been found most frequent, was screened by various restriction-enzyme analyses. Six patients were observed to have abnormal restriction patterns. By sequence analyses of the polymerase chain-reaction products, we identified a homozygous R1308C missense mutation in a patient with type 2B vWD; R1597W, R1597Q, G1609R and G1672R missense mutations in five patients with type 2A; and a G1659ter nonsense mutation in a patient with type 3 vWD. The G1672R was a novel missense mutation of the carboxyl-terminal end of the A2 domain. In addition, we detected an A/C polymorphism at nucleotide 4915 with HaeIII. There was no particular linkage disequilibrium of the A/C polymorphism, either with the G/A polymorphism at nucleotide 4391 detected with Hphl or with the C/T at 4891 detected with BstEll.


2010 ◽  
Vol 104 (09) ◽  
pp. 563-570 ◽  
Author(s):  
Petra Paulinska ◽  
Petra Jilma-Stohlawetz ◽  
James Gilbert ◽  
Renta Hutabarat ◽  
Paul Knöbl ◽  
...  

SummaryDesmopressin aggravates thrombocytopenia in type 2B von Willebrand disease (VWF type 2B) by release of large and hyper-adhesive von Wille-brand Factor (VWF) multimers. This pilot study investigated whether the anti-VWF aptamer ARC1779 can prevent desmopressin-induced thrombocytopenia and interferes with the excessive VWF turnover in patients with VWF type 2B. Concentration effect curves of ARC1779 were established for five patients in vitro and two patients with VWF type 2B were treated by infusion of ARC1779, desmopressin, or their combination in a randomised, controlled, double-blind design. ARC1779 concentrations in the range of 1–3 μg/ml blocked free A1 domain binding sites by 90% in vitro. In vivo, desmopressin alone induced a profound (-90%) drop in platelet counts in one of the patients. ARC1779 (4–5 μg/ml) completely inhibited VWF A1 domains and prevented this desmopress-in-induced platelet drop. Desmopressin alone increased VWF antigen two- to three-fold, accompanied by concordant changes in VWF Ristocetin cofactor activity (RCo) and coagulation factor VIII activity. ARC1779 substantially enhanced the desmopressin-induced maximal increase in these parameters, and improved multimer patterns. No treatment related adverse events were observed and no bleeding occurred despite marked thrombocytopenia. These data provide first proof of concept in humans and evidence that ARC1779 is a potent inhibitor of VWF. ARC1779 prevented the rapid consumption of VWF multimers together with agglutinated platelets that occurred in response to desmopressin challenge in patients with VWD type 2B.Clinical Trial registration number: NCT00632242.


Author(s):  
И.В. Куртов ◽  
Е.С. Фатенкова ◽  
Н.А. Юдина ◽  
А.М. Осадчук ◽  
И.Л. Давыдкин

Болезнь Виллебранда (БВ) может представлять определенные трудности у рожениц с данной патологией. Приведены 2 клинических примера использования у женщин с БВ фактора VIII свертывания крови с фактором Виллебранда, показана эффективность и безопасность их применения. У одной пациентки было также показано использование фактора свертывания крови VIII с фактором Виллебранда во время экстракорпорального оплодотворения. Von Willebrand disease presents a certain hemostatic problem among parturients. This article shows the effectiveness and safety of using coagulation factor VIII with von Willebrand factor for the prevention of bleeding in childbirth in 2 patients with type 3 von Willebrand disease. In one patient, the use of coagulation factor VIII with von Willebrand factor during in vitro fertilization was also shown.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4010-4010
Author(s):  
Jianfeng Yang ◽  
Zhi Chen ◽  
Weiliang Zhu ◽  
Changgeng Ruan

Abstract Abstract 4010 Poster Board III-946 Introduction Interaction of glycoprotein (GP) Ibα with Von Willebrand factor (VWF) plays a critical role in platelet adhesion and signal transduction for αIIbβ3 activation under condition of high shear stress. Methods Based on the crystal structure of platelet GPIbα (PDB:1P9A), virtual screening was employed to identify active compounds. Compounds in SPECS database were docked to VWF binding site on the surface of GPIbα. The screening was carried out with the DOCK4.0 program. The 150 highest-scoring compounds were obtained for further bioassay and those with inhibitory activity of VWF binding to GPIbα were investigated the effect on platelet activation and aggregation. Results We found one compound, designated it as YC148, blocked ristocetin-induced plasma VWF binding to recombinant N-terminal fragment GPIbα (H1-V289) by ELISA method. More interestingly, YC148 did not inhibit ristocetin-induced platelet aggregation, on the contrary, it induced platelet aggregation itself in the absence of exogenous modulators such as ristocetin and botrocetin. A VWF A1 blocking antibody could not block platelet aggregation induced by YC148 despite it completely inhibited ristocetin-induced platelet agglutination. And YC148 also stimulated washed platelet aggregation where VWF was absent in the resuspension buffer. These indicated that the aggregation stimulated by YC148 could not the result from VWF binding. Flow cytomety also showed that YC148 increased P-selectin expression on platelet membrane and promoted monoclonal antibody PAC-1 binding to platelet. The platelet aggregation stimulated by YC148 was inhibited by anti-GPIbα monoclonal antibody AN51 and 6D1. Conclusion A novel exogenous small-molecule agonist was found to activate platelet through binding to GPIbα. It provides us a new tool for investigating platelet GPIb outside-in signaling pathway in platelet adhesion and aggregation. Furthermore, the structure of YC148 may provide a structural basis for developing new hemostatic drugs based on the inhibition of VWF-GPIb interaction. The effect of YC148 on platelet from Bernard-Soulier syndrome or GPIbα N-terminal fragment deficient platelet after in vitro cleavage will be further investigated. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
1998 ◽  
Vol 92 (12) ◽  
pp. 4663-4670 ◽  
Author(s):  
S. Jorieux ◽  
C. Gaucher ◽  
J. Goudemand ◽  
C. Mazurier

Abstract In type 2N von Willebrand disease (vWD), von Willebrand factor (vWF) is characterized by normal multimeric pattern, normal platelet-dependent function, but a markedly decreased affinity for factor VIII (FVIII). In this report, we describe the case of a vWD patient who has an abnormal vWF multimers distribution associated with a markedly decreased vWF ability to bind FVIII. Sequencing analysis of patient’s vWF gene showed, at heterozygous state, a G→A transition resulting in the substitution of Asn for Asp at position 116 of the mature vWF subunit and a C→T transition, changing the codon for Arg 896 into a stop codon. His sister who has a subnormal vWF level, but a normal FVIII/vWF interaction, was found to be heterozygous for the Arg896ter mutation only. Recombinant vWF (rvWF) containing the candidate (Asn116) missense mutation was expressed in COS-7 cells. The expression level of Asn116rvWF was significantly decreased compared with wild-type rvWF. The multimeric pattern of Asn116rvWF was greatly impaired as shown by the decrease in high molecular weight forms. The FVIII binding ability of Asn116rvWF was dramatically decreased. These data show that the Asp116Asn substitution is the cause of both the defective FVIII/vWF interaction and the impaired multimeric pattern observed in the patient’s vWF. The monoclonal antibody 31H3 against D’ domain of vWF (epitope aa 66-76) that partially inhibits the FVIII binding and recognizes only nonreduced vWF, showed a decreased ability to bind Asn116rvWF when used as capture-antibody in enzyme-linked immunosorbent assay (ELISA). This result suggests that a potential conformation change in the D’ domain is induced by the Asp116Asn substitution, which is localized in the D3 domain.


2001 ◽  
Vol 86 (07) ◽  
pp. 246-258 ◽  
Author(s):  
Lisa Nannizzi-Alaimo ◽  
K. S. Srinivasa Prasad ◽  
David Phillips

SummaryThe platelet integrin αIIbβ3 not only binds fibrinogen and von Willebrand factor to mediate platelet aggregation and adhesion, it also serves as a signaling receptor. Platelet agonists such as ADP, thrombin and collagen induce “inside-out” signaling which activates the receptor function of αIIbβ3 for soluble fibrinogen. Subsequent platelet aggregation leads to “outside-in” signaling, inducing platelet aggregate stabilization and triggering a variety of functions important to platelet physiology. This review focuses on the role of β3 tyrosine phosphorylation in αIIbβ3 outside-in signaling. Tyrosine phosphorylation of β3 in platelets is a dynamic process which is initiated upon platelet aggregation and also by adhesion of platelets to immobilized fibrinogen. Tyrosine phosphorylation occurs on the β3 integrin cytoplasmic tyrosine (ICY) domain, a conserved motif found in thesubunits of several integrins. β3 ICY domain tyrosine phosphorylation induces the recruitment of two proteins to the cytoplasmic domains of αIIbβ3: the cytoskeletal protein myosin, important to clot retraction; and the signaling adapter protein Shc, important to platelet stimulation. The critical role of β3 tyrosine phosphorylation to platelet function was established by the diYF mouse, a novel strain which expresses an αIIbβ3 in which the two β3 ICY domain tyrosines have been mutated to phenylalanine. These mice are selectively impaired in outside-in αIIbβ3 signaling, with defective aggregation and clot-retraction responses in vitro, and an in vivo bleeding defect which is characterized by a pronounced tendency to rebleed. Taken together, the data suggest that the β3 tyrosine phosphorylation signaling mechanism is important to αIIbβ3 function and might be applicable to a wide variety of integrin-mediated events.


Blood ◽  
2001 ◽  
Vol 98 (2) ◽  
pp. 368-373 ◽  
Author(s):  
Heyu Ni ◽  
Vanitha Ramakrishnan ◽  
Zaverio M. Ruggeri ◽  
Jessie M. Papalia ◽  
David R. Phillips ◽  
...  

The glycoprotein (GP) Ib-V-IX complex plays a critical role in initiating platelet adhesion to von Willebrand factor (vWF) at the site of vascular injury. The complex also forms a high-affinity binding site for thrombin. Using an intravital microscopy mouse model, it was previously established that vWF plays a critical role in mediating platelet adhesion and thrombus formation following mesenteric arteriolar injury induced by ferric chloride. Further characterization of this model showed that these thrombotic events were also thrombin dependent. Using this vWF- and thrombin-dependent model, this study shows that GP V gene deficiency significantly accelerates both platelet adhesion and thrombus formation in mice following arteriolar injury. The time required for vessel occlusion in GP V–deficient (GP V−/−) mice was significantly shorter than that in wild-type mice. Interestingly, large emboli were also produced in GP V−/− mice, but not in wild-type mice, causing frequent downstream occlusion. However, when the 2 genotypes were compared in the in vitro perfusion chamber where thrombin was inhibited by heparin, no significant differences were found in either initial single-platelet adhesion or thrombus volume. These results demonstrate that GP V−/− mice have accelerated thrombus growth in response to vascular injury and suggest that this is caused by enhanced thrombin-induced platelet activation rather than enhanced binding of GPIb-V-IX to vWF. Absence of GP V also compromises thrombus stability.


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