scholarly journals Evidence for the Misfolding of the A1 Domain within Multimeric von Willebrand Factor in Type 2 von Willebrand Disease

2020 ◽  
Vol 432 (2) ◽  
pp. 305-323 ◽  
Author(s):  
Alexander Tischer ◽  
Maria A. Brehm ◽  
Venkata R. Machha ◽  
Laurie Moon-Tasson ◽  
Linda M. Benson ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

Molecular Background of “Smeary” von Willebrand Factor Multimers.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2711-2711
Author(s):  
Reinhard Schneppenheim ◽  
Olivier Marggraf ◽  
Heike Eckert ◽  
Tobias Obser ◽  
Florian Oyen ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Disulfide Bonds ◽  
Von Willebrand Disease ◽  
Molecular Testing ◽  
Functional Deficits ◽  
Intermolecular Disulfide Bonds ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Background: Multimer analysis of von Willebrand factor (VWF) is a most important technique to classify patients with von Willebrand disease (VWD) type 2. Besides “classical” multimer patterns a “smeary” appearance of individual VWF oligomers is increasingly observed and has previously been regarded as a pre-analytical artifact. Objective: To phenotypically and genotypically assess the molecular background of “smeary” VWF multimers. Patients and methods: Samples of 8 VWD patients were analyzed in our reference lab (UB) for further classification and molecular testing. Multimer profiles were assessed by intermediate resolution gels. VWF:CB and VWF:GpIb binding were used as functional assays. VWF gene mutation analysis was performed in all index cases (IC). The causal relationship between genotype and phenotype was studied by analyzing recombinant mutants in comparison to wildtype VWF. Results: In all IC the phenotype correlated with particular mutations in the VWF D3 domain (G1172D), the A1 domain (R1315C, R1374S, R1374C, R1399C), the D4 domain (C2257R), the C1 domain (R2464C) and in the region close to the CK domain (C2671Y), respectively. The multimer patterns of recombinant mutant VWF was of a “smeary” appearance and closely resembled those of mutant plasma VWF. Mutations in the A1 domain additionally correlated with severe GpIb binding deficiency. Conclusions: Our data suggest a molecular cause of the “smeary” multimer structure rather than pre-analytical artifacts. Most of the mutations identified involved cysteine residues suggesting an influence on the VWF secondary structure which is determined by intra- and intermolecular disulfide bonds. This could explain the peculiar multimer appearance. The functional deficits, however, seem to depend on the location of the mutations with a significant impact on GpIb binding of mutants in the A1 domain.

Defect of Heparin Binding in Plasma and Recombinant von Willebrand Factor with Type 2 von Willebrand Disease Mutations

2001 ◽  
Vol 86 (12) ◽  
pp. 1459-1465 ◽  
Author(s):  
Ghassem Rastegar-Lari ◽  
Nadine Ajzenberg ◽  
Anne-Sophie Ribba ◽  
Valérie Vereycken-Holler ◽  
Paulette Legendre ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Three Dimensional ◽  
Von Willebrand Disease ◽  
Dimensional Structure ◽  
Heparin Binding ◽  
Disease Mutations ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryThe aim of our study was to characterise heparin-binding properties of mutated von Willebrand factor (VWF) in 24 patients plasmas with type 2 von Willebrand disease (VWD), and in 15 recombinant VWF (rVWF) with the corresponding mutations. Binding of mutated rVWF or plasma VWF was compared to that of WT-rVWF or normal pool plasma VWF. Four mutations, at positions C509, V551, R552 and R611 lead to significantly decreased binding to heparin in both plasma and rVWF. Interestingly, whereas these four residues are distant in the primary structure of VWF-A1 domain, they are close to each other in its three-dimensional structure. Structural analysis suggested how folding problems and destabilisation due to these mutations could induce reorganisation of surface regions involved in heparin binding. In contrast, no heparin-binding defect was found associated with different type 2 VWF mutants, at positions G561, E596, I662, R543, R545, V553, R578 or L697.

Toward Personalized Treatment for Patients with Low von Willebrand Factor and Quantitative von Willebrand Disease

2021 ◽  
Vol 47 (02) ◽  
pp. 192-200
Author(s):  
James S. O'Donnell
Keyword(s):  
Von Willebrand Factor ◽  
Bleeding Risk ◽  
Von Willebrand Disease ◽  
Personalized Treatment ◽  
Treatment Plans ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractThe biological mechanisms involved in the pathogenesis of type 2 and type 3 von Willebrand disease (VWD) have been studied extensively. In contrast, although accounting for the majority of VWD cases, the pathobiology underlying partial quantitative VWD has remained somewhat elusive. However, important insights have been attained following several recent cohort studies that have investigated mechanisms in patients with type 1 VWD and low von Willebrand factor (VWF), respectively. These studies have demonstrated that reduced plasma VWF levels may result from either (1) decreased VWF biosynthesis and/or secretion in endothelial cells and (2) pathological increased VWF clearance. In addition, it has become clear that some patients with only mild to moderate reductions in plasma VWF levels in the 30 to 50 IU/dL range may have significant bleeding phenotypes. Importantly in these low VWF patients, bleeding risk fails to correlate with plasma VWF levels and inheritance is typically independent of the VWF gene. Although plasma VWF levels may increase to > 50 IU/dL with progressive aging or pregnancy in these subjects, emerging data suggest that this apparent normalization in VWF levels does not necessarily equate to a complete correction in bleeding phenotype in patients with partial quantitative VWD. In this review, these recent advances in our understanding of quantitative VWD pathogenesis are discussed. Furthermore, the translational implications of these emerging findings are considered, particularly with respect to designing personalized treatment plans for VWD patients undergoing elective procedures.

Effect of recombinant von Willebrand factor reproducing type 2B or type 2M mutations on shear-induced platelet aggregation

Blood ◽  
2000 ◽  
Vol 95 (12) ◽  
pp. 3796-3803 ◽  
Author(s):  
Nadine Ajzenberg ◽  
Anne-Sophie Ribba ◽  
Ghassem Rastegar-Lari ◽  
Dominique Meyer ◽  
Dominique Baruch
Keyword(s):  
Platelet Aggregation ◽  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
High Shear ◽  
Shear Rates ◽  
High Shear Rates ◽  
Consistent Increase ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The aim was to better understand the function of von Willebrand factor (vWF) A1 domain in shear-induced platelet aggregation (SIPA), at low (200) and high shear rate (4000 seconds-1) generated by a Couette viscometer. We report on 9 fully multimerized recombinant vWFs (rvWFs) expressing type 2M or type 2B von Willebrand disease (vWD) mutations, characterized respectively by a decreased or increased binding of vWF to GPIb in the presence of ristocetin. We expressed 4 type 2M (-G561A, -E596K, -R611H, and -I662F) and 5 type 2B (rvWF-M540MM, -V551F, -V553M, -R578Q, and -L697V). SIPA was strongly impaired in all type 2M rvWFs at 200 and 4000 seconds-1. Decreased aggregation was correlated with ristocetin binding to platelets. In contrast, a distinct effect of botrocetin was observed, since type 2M rvWFs (-G561A, -E596K, and -I662F) were able to bind to platelets to the same extent as wild type rvWF (rvWF-WT). Interestingly, SIPA at 200 and 4000 seconds-1 confirmed the gain-of-function phenotype of the 5 type 2B rvWFs. Our data indicated a consistent increase of SIPA at both low and high shear rates, reaching 95% of total platelets, whereas SIPA did not exceed 40% in the presence of rvWF-WT. Aggregation was completely inhibited by monoclonal antibody 6D1 directed to GPIb, underlining the importance of vWF-GPIb interaction in type 2B rvWF. Impaired SIPA of type 2M rvWF could account for the hemorrhagic syndrome observed in type 2M vWD. Increased SIPA of type 2B rvWF could be responsible for unstable aggregates and explain the fluctuant thrombocytopenia of type 2B vWD.

scholarly journals Identification of two mutations (Arg611Cys and Arg611His) in the A1 loop of von Willebrand factor (vWF) responsible for type 2 von Willebrand disease with decreased platelet-dependent function of vWF [see comments]

Blood ◽  
1995 ◽  
Vol 86 (3) ◽  
pp. 1010-1018 ◽  
Author(s):  
L Hilbert ◽  
C Gaucher ◽  
C Mazurier
Keyword(s):  
Von Willebrand Factor ◽  
Functional Characterization ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
In Vitro Mutagenesis ◽  
Nucleotide Substitutions ◽  
Dependent Function ◽  
Von Willebrand ◽  
Willebrand Factor

We report the identification of von Willebrand factor (vWF) gene mutations within exon 28 occurring in three unrelated families with an infrequent form of type 2 von Willebrand disease (vWD). A C-->T transition and a G-->A transition, both at the codon for arginine 611 of the mature vWF subunit, were found. They result in either a cysteine or an histidine substitution, respectively. Patients were found to be heterozygous for these substitutions and the vWD was transmitted dominantly. These substitutions have been reproduced by in vitro mutagenesis of full-length cDNA of vWF and transiently expressed in Cos- 7 cells. The corresponding recombinant vWFs (rvWF) exhibited decreased expression and a significant decrease in the high molecular weight multimeric forms. In addition, ristocetin- and botrocetin-induced binding of mutated rvWFs to platelets were markedly decreased as compared with that for the wild-type rvWFs. Thus, the structural and functional characterization of both mutated rvWFs confirmed that the two nucleotide substitutions identified at position 611 of the mature subunit of vWF are real mutations. Although they are located in the A1 loop containing most of the type 2B mutations inducing increased affinity of vWF for platelet glycoprotein Ib, they are responsible for abnormal vWF with decreased platelet-dependent function.

PFA-100 monitoring of von Willebrand factor (VWF) responses to desmopressin (DDAVP) and factor VIII/VWF concentrate substitution in von Willebrand disease type 1 and 2

2008 ◽  
Vol 100 (09) ◽  
pp. 462-468 ◽  
Author(s):  
Huub H. D. M. van Vliet ◽  
Mies C. Kappers-Klunne ◽  
Jan J. Michiels ◽  
Frank W. G. Leebeek
Keyword(s):  
Von Willebrand Factor ◽  
Von Willebrand Disease ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Before And After ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryDose-response relationship was studied between PFA-100 closure times (PFA CTs) and factor (F)VIII-von Willebrand factor (VWF) parameters in patients with von Willebrand disease (VWD) type 1 and type 2 before and after treatment with DDAVP (n=84) or FVIII/VWF concentrate (n=38). DDAVP treatment of patients with VWD type 1 normalised the PFA CTs by increasing VWF levels to normal. Of the 14 patients with VWD type 2, PFA CTs did not normalize in eight. Haemate-P substitution in patients with VWD type 1 induced a less favourable response as compared to DDAVP, because PFA CTs did not correct in all patients. Of 12 patients with VWD type 2 treated with Haemate-P, six showed a correction of PFA CTs (<250 sec), which correlated with the normalisation of the VWF CB/ Ag ratio. In-vitro studies were performed by using whole blood of patients with VWD and adding various amounts of FVIII/VWF concentrate. Addition of Haemate-P induced an increase of the VWF CB/Ag ratio from 0.30 to 0.70 in blood of patients with VWD type 2 with correction of the PFA CTs. Immunate did not result in an increase of VWF CB/Ag ratio in blood of VWD type 2 patients, and the PFA CTs remained prolonged. We conclude that PFA-100 might be an adequate instrument not only for diagnosis but also for monitoring of DDAVP responses and FVIII/ VWF substitution of patients with VWD type 1 and 2,but this is dependent upon the type of VWD and the concentrate used.

scholarly journals Type 2M:Milwaukee-1 von Willebrand disease: an in-frame deletion in the Cys509-Cys695 loop of the von Willebrand factor A1 domain causes deficient binding of von Willebrand factor to platelets

Blood ◽  
1996 ◽  
Vol 88 (7) ◽  
pp. 2559-2568 ◽  
Author(s):  
DJ Mancuso ◽  
PA Kroner ◽  
PA Christopherson ◽  
EA Vokac ◽  
JC Gill ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Genetic Defect ◽  
Binding Activity ◽  
Von Willebrand Disease ◽  
Variant Form ◽  
New Variant ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

This report examines the genetic basis of a variant form of moderately severe von Willebrand disease (vWD) characterized by low plasma von Willebrand factor antigen (vWF:Ag) levels and normal multimerization, typical of type 1 vWD, but disproportionately-low agonist-mediated platelet-binding activity. We identified an in-frame deletion in vWF exon 28 in three generations of affected family members, who are heterozygous for this mutation. The deletion of nucleotides 4,173–4,205 results in the loss of amino acids Arg629-Gln639 in the Cys509-Cys695 loop of the A1 domain in mature vWF. The secreted mutant vWF showed a normal multimeric profile but did not bind to platelets in the presence of optimal concentrations of either ristocetin or botrocetin. The mutant vWF also failed to interact with heparin, and with vWF monoclonal antibody AvW3, which blocks the binding of vWF to GPlb. In addition, mutant vWF showed reduced secretion from transfected cells concomitant with increased intracellular levels. These results confirm that the deletion is the genetic defect responsible for the reduced interaction of vWF with platelets. We have designated this new variant type 2M:Milwaukee-1 vWD. Our analysis suggests that the potential frequency of this phenotype in individuals diagnosed with type 1 vWD is about 0.5%.

scholarly journals Identification of two mutations (Arg611Cys and Arg611His) in the A1 loop of von Willebrand factor (vWF) responsible for type 2 von Willebrand disease with decreased platelet-dependent function of vWF [see comments]

Blood ◽  
1995 ◽  
Vol 86 (3) ◽  
pp. 1010-1018 ◽  
Author(s):  
L Hilbert ◽  
C Gaucher ◽  
C Mazurier
Keyword(s):  
Von Willebrand Factor ◽  
Functional Characterization ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
In Vitro Mutagenesis ◽  
Nucleotide Substitutions ◽  
Dependent Function ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract We report the identification of von Willebrand factor (vWF) gene mutations within exon 28 occurring in three unrelated families with an infrequent form of type 2 von Willebrand disease (vWD). A C-->T transition and a G-->A transition, both at the codon for arginine 611 of the mature vWF subunit, were found. They result in either a cysteine or an histidine substitution, respectively. Patients were found to be heterozygous for these substitutions and the vWD was transmitted dominantly. These substitutions have been reproduced by in vitro mutagenesis of full-length cDNA of vWF and transiently expressed in Cos- 7 cells. The corresponding recombinant vWFs (rvWF) exhibited decreased expression and a significant decrease in the high molecular weight multimeric forms. In addition, ristocetin- and botrocetin-induced binding of mutated rvWFs to platelets were markedly decreased as compared with that for the wild-type rvWFs. Thus, the structural and functional characterization of both mutated rvWFs confirmed that the two nucleotide substitutions identified at position 611 of the mature subunit of vWF are real mutations. Although they are located in the A1 loop containing most of the type 2B mutations inducing increased affinity of vWF for platelet glycoprotein Ib, they are responsible for abnormal vWF with decreased platelet-dependent function.

Mutation distribution in the von Willebrand factor gene related to the different von Willebrand disease (VWD) types in a cohort of VWD patients

2012 ◽  
Vol 108 (10) ◽  
pp. 662-671 ◽  
Author(s):  
Hamideh Yadegari ◽  
Julia Driesen ◽  
Anna Pavlova ◽  
Arijit Biswas ◽  
Hans-Jörg Hertfelder ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Splice Site ◽  
Von Willebrand Disease ◽  
Missense Mutations ◽  
Large Deletions ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryVon Willebrand disease (VWD) is the most common inherited bleeding disorder caused by quantitative or qualitative defects of the von Willebrand factor (VWF). VWD is classified into three types – type 1 (partial quantitative deficiencies), type 2 (qualitative defects) and type 3 (complete deficiency of VWF). In this study we explored genotype and phenotype characteristics of patients with VWD with the aim of dissecting the distribution of mutations in different types of VWD. One hundred fourteen patients belonging to 78 families diagnosed to have VWD were studied. Mutation analysis was performed by direct sequencing of the VWF. Large deletions were investigated by multiplex ligation-dependent probe amplification (MLPA) analysis. The impact of novel candidate missense mutations and potential splice site mutations was predicted by in silico assessments. We identified mutations in 66 index patients (IPs) (84.6%). Mutation detection rate was 68%, 94% and 94% for VWD type 1, 2 and 3, respectively. In total, 68 different putative mutations were detected comprising 37 missense mutations (54.4%), 10 small deletions (14.7%), two small insertions (2.9%), seven nonsense mutations (10.3%), five splice-site mutations (7.4%), six large deletions (8.8%) and one silent mutation (1.5%). Twenty-six of these mutations were novel. Furthermore, in type 1 and type 2 VWD, the majority of identified mutations (74% vs. 88.1%) were missense substitutions while mutations in type 3 VWD mostly caused null alleles (82%). Genotyping in VWD is a helpful tool to further elucidate the pathogenesis of VWD and to establish the relationship between genotype and phenotype.

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