scholarly journals Proteolytic resistance conferred to fibrinogen by von Willebrand factor

2010 ◽  
Vol 103 (02) ◽  
pp. 291-298 ◽  
Author(s):  
Anna Tanka-Salamon ◽  
Raymund Machovich ◽  
Erzsebet Komorowicz ◽  
Krasimir Kolev
Keyword(s):  
Von Willebrand Factor ◽  
Active Site ◽  
Competitive Inhibition ◽  
Dissociation Constants ◽  
Degradation Products ◽  
Kinetic Measurements ◽  
Proteolytic Resistance ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryThe formation of platelet-rich thrombi under high shear rates requires both fibrinogen and von Willebrand factor (VWF) as molecular adhesives between platelets. We attempted to describe the role of VWF as a potential substrate and modulator of the fibrinolytic system using binding assays, as well as kinetic measurements on the cleavage of fibrin(ogen) and a synthetic plasmin substrate (Spectrozyme-PL). The similar dissociation constants for the binding of plasminogen, plasmin, and active site-blocked plasmin onto immobilised VWF suggest that the primary binding site in plasmin(ogen) is not the active site. The progressive loss of clottability and generation of degradation products during fibrinogen digestion with plasmin were delayed in the presence of VWF at physiological concentrations, while VWF cleavage was not detectable. Determination of kinetic parameters for fibrinogen degradation by plasmin, miniplasmin and microplasmin showed that VWF did not modify the Km, whereas kcat values decreased with increasing VWF concentrations following the kinetic model of non-competitive inhibition. Inhibitory constants calculated for VWF were in the range of its physiological plasma concentration (5.4 μg/ml, 5.7 μg/ml and 10.0 μg/ ml for plasmin, miniplasmin and microplasmin, respectively) and their values suggested a modulating role of the kringle 5 domain in the interaction between VWF and (mini)plasmin. VWF had no effect on the amidolytic activity of plasmin on Spectrozyme-PL, or on fibrin dissolution by (mini)plasmin. Our data suggest that VWF, while a poor plasmin substrate relative to fibrinogen, protects fibrinogen against degradation by plasmin preserving its clottability in plasma and its adhesive role in platelet-rich thrombi.

The role of von Willebrand factor in the development of systemic infl ammation, coagulopathy and organ dysfunctions

2021 ◽  
Author(s):  
А.В. Лянгузов ◽  
О.Ю. Сергунина ◽  
С.В. Игнатьев ◽  
М.Е. Ковтунова ◽  
С.Л. Калинина ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Degradation Products ◽  
Kidney Injury ◽  
Multiple Organ ◽  
Local Inhibition ◽  
Inflammatory Processes ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
The Complement System

Фактор фон Виллебранда (vWF) является мультимерным гликопротеином, который играет ключевую роль в осуществлении тромбоцитарного и плазменного гемостаза. В последние годы выявлено участие vWF в ангиогенезе, апоптозе нормальных и опухолевых клеток, определена его транспортная роль. Комплекс vWF и фермента ADAMTS-13, который отвечает за его расщепление, имеет существенное значение в развитии воспалительных процессов. Механизмы такого участия vWF различны и включают в себя взаимодействие с микроорганизмами, форменными элементами крови и продуктами их распада, внеклеточными ловушками нейтрофилов, системой комплемента и др. Уникальные свойства молекулы vWF при сепсисе способствуют развитию и прогрессированию коагулопатии. Системное воспаление вносит дополнительный вклад в опосредованное ADAMTS-13 локальное ингибирование расщепления vWF и усугубляет дисбаланс соотношения vWF/ADAMTS-13, тем самым способствуя развитию распространенной внутрисосудистой коагуляции. Образование ультрабольших мультимеров vWF и дефицит ADAMTS-13 выявлены при сепсисе, тяжелом течении COVID-19, черепно-мозговой и сочетанной травме, остром повреждении почек и др. В основе патогенеза возникающей при этом полиорганной недостаточности лежит развитие микроангиопатии и микрососудистых тромбозов. Возможными методами коррекции нарушений в системе vWF/ADAMTS-13 являются применение терапевтического плазмообмена, гепарина, N-ацетилцистеина, рекомбинантного ADAMTS-13, препаратов магния. Von Willebrand factor (vWF) is a multimeric glycoprotein that plays a key role in platelet and plasma hemostasis. In recent years, the involvement of vWF in angiogenesis, apoptosis of normal and tumor cells has been revealed, and its transport role has been determined. The complex of vWF and enzyme ADAMTS-13, which is responsible for its splitting, is essential in the development of inflammatory processes. The mechanisms of vWF participation in inflammatory processes varies and include interaction with microorganisms, blood cells and their degradation products, neutrophil extracellular traps, the complement system, etc. The unique qualities of the vWF contribute to the development and progression of coagulopathy in sepsis. Systemic inflammation enhances local inhibition of vWF cleavage and exacerbates an imbalance in the vWF/ADAMTS-13 ratio, which contributes to the development of intravascular coagulation. The formation of ultralarge vWF (ULvWF) multimers and ADAMTS-13 deficiency were detected in sepsis, severe COVID-19, craniocerebral and concomitant trauma, acute kidney injury, etc. The pathogenesis of the resulting multiple organ failure due to the accumulation of ULvWF is based on the development of microangiopathy and microvascular thrombosis. Possible methods for correcting disorders in the vWF/АDAMTS-13 system are the use of therapeutic plasma exchange, heparin, N-acetylcysteine, recombinant ADAMTS-13, and magnesium preparations.

scholarly journals The cooperative activity between the carboxyl-terminal TSP1 repeats and the CUB domains of ADAMTS13 is crucial for recognition of von Willebrand factor under flow

Blood ◽  
2007 ◽  
Vol 110 (6) ◽  
pp. 1887-1894 ◽  
Author(s):  
Ping Zhang ◽  
Weilan Pan ◽  
Ann H. Rux ◽  
Bruce S. Sachais ◽  
X. Long Zheng
Keyword(s):  
Von Willebrand Factor ◽  
Dissociation Constants ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cooperative Activity ◽  
Carboxyl Terminal ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract ADAMTS13 cleaves von Willebrand factor (VWF) between Tyr1605 and Met1606 residues at the central A2 subunit. The amino-terminus of ADAMTS13 protease appears to be sufficient to bind and cleave VWF under static and denatured condition. However, the role of the carboxyl-terminus of ADAMTS13 in substrate recognition remains controversial. Present study demonstrates that ADAMTS13 cleaves VWF in a rotation speed– and protease concentration–dependent manner on a mini vortexer. Removal of the CUB domains (delCUB) or truncation after the spacer domain (MDTCS) significantly impairs its ability to cleave VWF under the same condition. ADAMTS13 and delCUB (but not MDTCS) bind VWF under flow with dissociation constants (KD) of about 50 nM and about 274 nM, respectively. The isolated CUB domains are neither sufficient to bind VWF detectably nor capable of inhibiting proteolytic cleavage of VWF by ADAMTS13 under flow. Addition of the TSP1 5-8 (T5-8CUB) or TSP1 2-8 repeats (T2-8CUB) to the CUB domains restores the binding affinity toward VWF and the inhibitory effect on cleavage of VWF by ADAMTS13 under flow. These data demonstrate directly and quantitatively that the cooperative activity between the middle carboxyl-terminal TSP1 repeats and the distal carboxyl-terminal CUB domains may be crucial for recognition and cleavage of VWF under flow.

Ristocetin and Botrocetin Involve Two Distinct Domains of von Willebrand Factor for Binding to Platelet Membrane Glycoprotein lb

1990 ◽  
Vol 64 (02) ◽  
pp. 326-332 ◽  
Author(s):  
J P Girma ◽  
Y Takahashi ◽  
A Yoshioka ◽  
J Diaz ◽  
D Meyer
Keyword(s):  
Von Willebrand Factor ◽  
Synthetic Peptides ◽  
Competitive Inhibition ◽  
Final Concentration ◽  
Binding Domain ◽  
Platelet Membrane ◽  
Platelet Glycoprotein ◽  
Membrane Glycoprotein ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryWe have evidence that ristocetin and botrocetin mediate binding of von Willebrand Factor (vWF) to platelet glycoprotein lb (GPIb) through two distinct domains on the vWF molecule. This was established by using monoclonal antibodies (MAbs) to vWF and synthetic peptides derived from the sequence of vWF. MAb 322 and MAb NMC/vW 4 both recognize native vWF as well as fragments containing the GPIb-binding domain of vWF, obtained with the following enzymes: trypsin (116 kDa), V-8 pro tease (Spill, 320 kDa) and V-8 protease plus subtilisin (33-28 kDa). Nevertheless, the lack of reciprocal displacement between the two MAbs in experiments of competitive inhibition for binding to vWF demonstrate that their respective epitopes are separate. Both MAbs inhibit 125I-vWF binding to platelet membrane GPIb and vWF-dependent platelet agglutination induced by ristocetin. However, only MAb NMC/vW4 inhibits these functions in the presence of botrocetin and when ristocetin-induced platelet agglutination is inhibited by MAb 322, botrocetin is still able to restore the agglutination. The involvement of two distinct domains of vWF for binding to GPIb in the presence of ristocetin or botrocetin was confirmed in experiments of binding of 125I-vWF to platelets using as competitor synthetic peptides corresponding to the GPIb binding domain of vWF (Cys 474 to Pro 488 and Ser 692 to Pro 708). At a final concentration of 2.5 mM both peptides inhibit more than 90% of the binding of vWF to ristocetin-treated platelets but are unable to modify this binding in the presence of botrocetin. In conclusion our data suggest that botrocetin and ristocetin involve distinct sites on vWF for binding to GPIb.

scholarly journals The role of von Willebrand factor in breast cancer metastasis

2021 ◽  
Vol 14 (4) ◽  
pp. 101033
Author(s):  
Chia Yin Goh ◽  
Sean Patmore ◽  
Albert Smolenski ◽  
Jane Howard ◽  
Shane Evans ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Von Willebrand Factor ◽  
Cancer Metastasis ◽  
Breast Cancer Metastasis ◽  
Von Willebrand ◽  
Willebrand Factor

Role of Platelet Membrane Glycoproteins and Von Willebrand Factor in Adhesion of Platelets to Subendothelium and Collagen

1987 ◽  
Vol 516 (1 Blood in Cont) ◽  
pp. 52-65 ◽  
Author(s):  
KJELL S. SAKARIASSEN ◽  
EDITH FRESSINAUD ◽  
JEAN-PIERRE GIRMA ◽  
DOMINIQUE MEYER ◽  
HANS R. BAUMGARTNER
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Membrane ◽  
Membrane Glycoproteins ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Adhesion Of Platelets

scholarly journals Partial characterization of a binding site for von Willebrand factor on glycocalicin

Blood ◽  
1986 ◽  
Vol 67 (1) ◽  
pp. 19-26 ◽  
Author(s):  
AD Michelson ◽  
J Loscalzo ◽  
B Melnick ◽  
BS Coller ◽  
RI Handin
Keyword(s):  
Binding Site ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Binding Activity ◽  
Proteolytic Fragment ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Beta Galactosidase

The binding of von Willebrand factor (vWF) to platelet membrane glycoprotein Ib (GpIb) facilitates platelet adhesion to vascular subendothelium. In this study, we provide evidence that the vWF binding site is on glycocalicin (GC), a proteolytic fragment of GpIb, and we examine the role of the carbohydrate portion of GC on that binding. The binding to platelets of 6D1, a monoclonal antibody that recognizes an epitope on GpIb and blocks ristocetin-induced vWF binding to platelets, was inhibited by purified GC. In addition, purified GC inhibited ristocetin-dependent binding of 125I-labeled vWF to platelets. Since GC contains 60% carbohydrate by weight, we assessed the role of carbohydrate sequences on its interaction with antibody 6D1 and vWF. Based on the known sequence of the major oligosaccharide chain of GC--N- acetyl neuraminic acid, galactose, N-acetyl glucosamine, N-acetyl galactosamine--we treated GC sequentially with neuraminidase, beta- galactosidase, and beta-N-acetylglucosaminidase. Removal of sialic acid and galactose residues did not affect GC binding. Removal of N-acetyl glucosamine residues did not affect GC binding to 6D1 but did decrease the ability of GC to inhibit vWF binding to platelets, increasing the concentration needed to inhibit binding by 50% (IC50) 40-fold. This suggests that a portion of the oligosaccharide chains on GC contributes to the vWF binding activity of this molecule.

scholarly journals Platelet von Willebrand factor: evidence for its involvement in platelet adhesion to collagen

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 1214-1217
Author(s):  
E Fressinaud ◽  
D Baruch ◽  
C Rothschild ◽  
HR Baumgartner ◽  
D Meyer
Keyword(s):  
Shear Rate ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Von Willebrand Disease ◽  
High Shear ◽  
Shear Rates ◽  
High Shear Rates ◽  
Von Willebrand ◽  
Willebrand Factor

Although it is well established that plasma von Willebrand Factor (vWF) is essential to platelet adhesion to subendothelium at high shear rates, the role of platelet vWF is less clear. We studied the respective role of both plasma and platelet vWF in mediating platelet adhesion to fibrillar collagen in a parallel-plate perfusion chamber. Reconstituted blood containing RBCs, various mixtures of labeled washed platelets and plasma from controls or five patients with severe von Willebrand disease (vWD), was perfused through the chamber for five minutes at a shear rate of 1,600 s-1. Platelet-collagen interactions were estimated by counting the radioactivity in deposited platelets and by quantitative morphometry. When the perfusate consisted of normal platelets suspended in normal plasma, platelet deposition on the collagen was 24.7 +/- 3.6 X 10(6)/cm2 (mean +/- SEM, n = 6). Significantly less deposition (16 +/- 2.3) was observed when vWD platelets were substituted for normal platelets. In mixtures containing vWD plasma, significantly greater deposition (9 +/- 2.2) was obtained with normal than with vWD platelets (1 +/- 0.4) demonstrating a role for platelet vWF in mediating the deposition of platelets on collagen. Morphometric analysis confirmed these data. Our findings indicate that platelet, as well as plasma, vWF mediates platelet-collagen interactions at a high shear rate.

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