Soluble plasma-derived von Willebrand factor assembles to a haemostatically active filamentous network

2007 ◽  
Vol 97 (04) ◽  
pp. 514-526 ◽  
Author(s):  
Alexej Barg ◽  
Rainer Ossig ◽  
Tobias Goerge ◽  
Hermann Schillers ◽  
Hans Oberleithner ◽  
...  
Keyword(s):  
Self Assembly ◽  
Collagen Matrix ◽  
Cellular Membrane ◽  
Force Microscopy ◽  
Atomic Force ◽  
Binding Surface ◽  
Self Association ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Microscopy Images

SummaryThe large glycoprotein vonWillebrand factor (VWF) is involved in the initial haemostatic reaction mediating the interaction between platelets and the injured vessel wall. It has been demonstrated that unusually large VWF (ULVWF) multimers after being released from endothelium are capable of developing elongated membrane-anchored strings that are hyperactive to bind platelets. In the present study we investigated whether soluble plasma-derived VWF is competent to develop similar thrombotically active multimers. We demonstrated that soluble VWF multimers isolated from human plasma self-assemble to a network of fibers immobilized on a collagen matrix and are functionally active to bind platelets. Formation of these VWF fibers depends on shear flow, concentration of solubleVWF, and a suitable binding surface. Self-assembly of soluble VWF does not require the presence of cellular membrane ligands. The network of fibers is subjected to rapid degradation by proteolytic activity of plasma ADAMTS-13.Atomic force microscopy images elucidate the nanostructure of VWF fibers and illustrate self-association and -aggregation of several filamentous multimers. Together, these results suggest that circulatingVWF can contribute to a formation of hyperactive VWF fibers on exposed subendothelial collagen during vascular injury.

Investigation of the Morphology of Recombinant Von Willebrand Factor by Two High-Resolution Microscopic Techniques

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1409-1409
Author(s):  
Hanspeter Rottensteiner ◽  
Birgit K Seyfried ◽  
Gernot Friedbacher ◽  
Guenter Allmaier ◽  
Nicola Ilk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Life Sciences ◽  
Force Microscopy ◽  
Atomic Force ◽  
University Of Technology ◽  
Transmission Electron ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Mode Atomic Force Microscopy

Abstract Abstract 1409 Von Willebrand factor (VWF) is the largest known glycoprotein circulating in human blood plasma and is composed of a series of multimers with molecular weights ranging from 600 to 20,000 kDa or even more. In this study, we investigated the morphology of recombinant VWF (rVWF) and compared it to that of plasma-derived VWF (pdVWF) by tapping mode atomic force microscopy and transmission electron microscopy. Tapping mode atomic force microscopy showed that both rVWF and pdVWF contain globular and stretched domains. Mean chain lengths of the filaments and diameters of the core globular domains were determined and analyzed on a statistical basis. About 70% of the rVWF and pdVWF molecules were 100–300 nm long. The portion of very long molecules (>300 nm) was only slightly greater in rVWF than in pdVWF (20% versus 18%). The diameters of the globular core structures were in the range of 12 to 30 nm for both types of VWF. Inspection of a purified rVWF dimer revealed a similar range for the globular domain (14-32 nm). Upon exposure to high shear stress, a dramatic conformational change was observed for rVWF, just as has been reported for pdVWF. Investigation of negatively stained preparations of rVWF by transmission electron microscopy showed a highly organized structure. The heterogeneity in size observed was as expected for a polymeric VWF that consists of a mixture of multimers of varying sizes. The micrographs also revealed the presence of coiled and elongated structures. Analysis of pdVWF led to similar results, which were also in agreement with data from the literature. The results confirmed that the morphology of rVWF is similar to that observed for VWF purified from human normal plasma. Disclosures: Rottensteiner: Baxter Innovations GmbH: Employment. Seyfried:Baxter Innovations GmbH: Employment. Friedbacher:Vienna University of Technology: Consultancy. Allmaier:Vienna University of Technology: Consultancy. Ilk:University of Natural Resources and Applied Life Sciences: Consultancy. Sleytr:University of Natural Resources and Applied Life Sciences: Consultancy. Ehrlich:Baxter Innovations GmbH: Employment. Turecek:Baxter BioScience: Employment.

Shear and Substrate Dependent Changes in Fibrinogen and Von Willebrand Factor Studied by Atomic Force Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 924-925
Author(s):  
Roger E. Marchant ◽  
P. Sidney Sit ◽  
Madhusudan Raghavachari ◽  
Christopher A. Siedlecki
Keyword(s):  
Atomic Force Microscopy ◽  
Von Willebrand Factor ◽  
Hydrophobic Surface ◽  
Three Dimensions ◽  
Human Fibrinogen ◽  
Force Microscopy ◽  
Atomic Force ◽  
Aqueous Conditions ◽  
Von Willebrand ◽  
Willebrand Factor

Atomic force microscopy (AFM) provides unique opportunities to study cell-surface and molecular scale interactions in three dimensions under aqueous conditions. Two plasma proteins, von Willebrand Factor (vWf) and fibrinogen, play central roles in the regulation of hemostasis and thrombosis by participating in coagulation and facilitating adhesion and aggregation of activated platelets. vWf and fibrinogen are believed to facilitate platelet adhesion under regions of relatively high and low vascular wall shear stress, respectively. Consequently, elucidating vWf and fibrinogen structure-function relations under shear is of considerable importance in developing a comprehensive understanding of the pathophysiology of thrombogenesis. Previously, we reported on molecular level AFM images of human vWf during shear-induced structural transition and human fibrinogen under aqueous conditions when both proteins were adsorbed on a hydrophobic surface. This presentation will report on the shear dependent interactions of dimeric and multimeric vWf with a hydrophobic surface and the substrate-dependent interactions of fibrinogen.

scholarly journals Interactions of von Willebrand factor on mica studied by atomic force microscopy

1992 ◽  
Vol 148 (1) ◽  
pp. 261-272 ◽  
Author(s):  
Roger E Marchant ◽  
A.Scott Lea ◽  
Joseph D Andrade ◽  
Paula Bockenstedt
Keyword(s):  
Atomic Force Microscopy ◽  
Von Willebrand Factor ◽  
Force Microscopy ◽  
Atomic Force ◽  
Von Willebrand ◽  
Willebrand Factor

scholarly journals Force sensing by the vascular protein von Willebrand factor is tuned by a strong intermonomer interaction

2016 ◽  
Vol 113 (5) ◽  
pp. 1208-1213 ◽  
Author(s):  
Jochen P. Müller ◽  
Salomé Mielke ◽  
Achim Löf ◽  
Tobias Obser ◽  
Christof Beer ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Single Molecule ◽  
Effective Length ◽  
Force Sensing ◽  
Force Microscopy ◽  
Atomic Force ◽  
Increased Risk ◽  
Afm Imaging ◽  
Von Willebrand ◽  
Willebrand Factor

The large plasma glycoprotein von Willebrand factor (VWF) senses hydrodynamic forces in the bloodstream and responds to elevated forces with abrupt elongation, thereby increasing its adhesiveness to platelets and collagen. Remarkably, forces on VWF are elevated at sites of vascular injury, where VWF’s hemostatic potential is important to mediate platelet aggregation and to recruit platelets to the subendothelial layer. Adversely, elevated forces in stenosed vessels lead to an increased risk of VWF-mediated thrombosis. To dissect the remarkable force-sensing ability of VWF, we have performed atomic force microscopy (AFM)-based single-molecule force measurements on dimers, the smallest repeating subunits of VWF multimers. We have identified a strong intermonomer interaction that involves the D4 domain and critically depends on the presence of divalent ions, consistent with results from small-angle X-ray scattering (SAXS). Dissociation of this strong interaction occurred at forces above ∼50 pN and provided ∼80 nm of additional length to the elongation of dimers. Corroborated by the static conformation of VWF, visualized by AFM imaging, we estimate that in VWF multimers approximately one-half of the constituent dimers are firmly closed via the strong intermonomer interaction. As firmly closed dimers markedly shorten VWF’s effective length contributing to force sensing, they can be expected to tune VWF’s sensitivity to hydrodynamic flow in the blood and to thereby significantly affect VWF’s function in hemostasis and thrombosis.

Comparison of plasma-derived and recombinant von Willebrand factor by atomic force microscopy

2010 ◽  
Vol 104 (09) ◽  
pp. 523-530 ◽  
Author(s):  
Birgit Seyfried ◽  
Gernot Friedbacher ◽  
Hanspeter Rottensteiner ◽  
Hans Peter Schwarz ◽  
Hartmut Ehrlich ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Shear Stress ◽  
Von Willebrand Factor ◽  
Globular Domain ◽  
Force Microscopy ◽  
Molecular Weights ◽  
Atomic Force ◽  
Similar Range ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryHuman plasma protein von Willebrand factor (VWF) is composed of a series of multimers with molecular weights ranging from 600 to 20,000 kDa or even more. Plasma-derived VWF (pdVWF) and recombinant VWF (rVWF) differ in that the ultra-large molecular weight multimer portion present in rVWF is usually missing in pdVWF due to partial cleavage of VWF by the plasma protease ADAMTS13. Here, tapping mode atomic force microscopy (TM-AFM) was used to visualise the shape and size of rVWF and pdVWF. The morphology of the variants of VWF was comparable, containing both globular and stretched domains. Mean chain lengths of the filaments and diameters of the core globular domains were determined and analysed on a statistical basis. About 72% of the pdVWF molecules and 70% of the rVWF molecules were 100–300 nm long. The portion of very long molecules (>300 nm) was only slightly greater in rVWF than in pdVWF (20% vs. 18%). The diameters of the globular core structures were in the range of 12 to 30 nm for both types of VWF. Inspection of a purified rVWF dimer revealed a similar range for the globular domain (14–32 nm). Finally, we demonstrate a dramatic conformational change for rVWF upon exposure to high shear stress, as has been reported for pdVWF. Our TM-AFM data show that the overall structure of rVWF is similar to that of pdVWF and that rVWF will extend its conformation under shear stress, which is required to exert its function in primary haemostasis.

scholarly journals PlA2 Polymorphism in Glycoprotein IIb/IIIa Modulates the Morphology and Nanomechanics of Platelets

2017 ◽  
Vol 23 (8) ◽  
pp. 951-960 ◽  
Author(s):  
Svetla Todinova ◽  
Regina Komsa-Penkova ◽  
Sashka Krumova ◽  
Stefka G. Taneva ◽  
Georgy Golemanov ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Membrane Elasticity ◽  
Platelet Surface ◽  
Force Microscopy ◽  
Topographic Features ◽  
Atomic Force ◽  
Afm Imaging ◽  
Surface Receptor ◽  
Von Willebrand ◽  
Willebrand Factor

Glycoprotein IIb/IIIa (GPIIb/IIIa) is the most abundant platelet surface receptor for fibrinogen and von Willebrand factor. Polymorphism PlA1/A2 in the gene of GPIIb/IIIa is among the risk factors for the development of arterial and venous thrombosis. The aim of this study is to evaluate the effect of the carriage of PlA1/A2 on the size, topographic features, and membrane stiffness of platelets from healthy controls and patients with deep venous thrombosis (DVT). Atomic force microscopy (AFM) imaging and nanoindentation (force–distance curves) were applied to investigate the morphological and nanomechanical properties (Young’s modulus) of platelets immobilized on glass surface. The surface roughness ( Ra) and height ( h) of platelets from patients with DVT, carriers of mutant allele PlA2 ( Ra = 30.2 ± 6 nm; h = 766 ± 182 nm) and noncarriers ( Ra = 28.6 ± 6 nm; h = 865 ± 290 nm), were lower than those of healthy carriers of allele PlA2 ( Ra = 48.1 ± 12 nm; h = 1072 ± 338 nm) and healthy noncarriers ( Ra = 49.7 ± 14 nm; h = 1021 ± 433 nm), respectively. Platelets isolated from patients with DVT, both carriers and noncarriers, exhibit much higher degree of stiffness at the stage of spreading ( E = 327 ± 85 kPa and 341 ± 102 kPa, respectively) compared to healthy noncarriers ( E = 198 ± 50 kPa). In addition, more pronounced level of platelet activation was found in polymorphism carriers. In conclusion, the carriage of PlA2 allele modulates the activation state, morphology, and membrane elasticity of platelets.

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