scholarly journals Platelet heterogeneity in activation-induced glycoprotein shedding: functional effects

2018 ◽  
Vol 2 (18) ◽  
pp. 2320-2331 ◽  
Author(s):  
Constance C. F. M. J. Baaten ◽  
Frauke Swieringa ◽  
Tomasz Misztal ◽  
Tom G. Mastenbroek ◽  
Marion A. H. Feijge ◽  
...  
Keyword(s):  
Thrombus Formation ◽  
Coagulation Factors ◽  
Fibrin Formation ◽  
Kinase C ◽  
Receptor Shedding ◽  
Adam Family ◽  
Activation Pathways ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Stimulation Of

Abstract The platelet receptors glycoprotein Ibα (GPIbα) and GPVI are known to be cleaved by members of a disintegrin and metalloprotease (ADAM) family (ADAM10 and ADAM17), but the mechanisms and consequences of this shedding are not well understood. Our results revealed that (1) glycoprotein shedding is confined to distinct platelet populations showing near-complete shedding, (2) the heterogeneity between (non)shed platelets is independent of agonist type but coincides with exposure of phosphatidylserine (PS), and (3) distinct pathways of shedding are induced by elevated Ca2+, low Ca2+ protein kinase C (PKC), or apoptotic activation. Furthermore, we found that receptor shedding reduces binding of von Willebrand factor, enhances binding of coagulation factors, and augments fibrin formation. In response to Ca2+-increasing agents, shedding of GPIbα was abolished by ADAM10/17 inhibition but not by blockage of calpain. Stimulation of PKC induced shedding of only GPIbα, which was annulled by kinase inhibition. The proapoptotic agent ABT-737 induced shedding, which was caspase dependent. In Scott syndrome platelets that are deficient in Ca2+-dependent PS exposure, shedding occurred normally, indicating that PS exposure is not a prerequisite for ADAM activity. In whole-blood thrombus formation, ADAM-dependent glycoprotein shedding enhanced thrombin generation and fibrin formation. Together, these findings indicate that 2 major activation pathways can evoke ADAM-mediated glycoprotein shedding in distinct platelet populations and that shedding modulates platelet function from less adhesive to more procoagulant.

Signaling through GP Ib-IX-V activates αIIbβ3 independently of other receptors

Blood ◽  
2004 ◽  
Vol 103 (9) ◽  
pp. 3403-3411 ◽  
Author(s):  
Ana Kasirer-Friede ◽  
Maria Rita Cozzi ◽  
Mario Mazzucato ◽  
Luigi De Marco ◽  
Zaverio M. Ruggeri ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Platelet Adhesion ◽  
Thrombus Formation ◽  
Signaling Proteins ◽  
Phosphatidylinositol 3 Kinase ◽  
Kinase C ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Pharmacologic Inhibition

Abstract Platelet adhesion to von Willebrand factor (VWF) activates αIIbβ3, a prerequisite for thrombus formation. However, it is unclear whether the primary VWF receptor, glycoprotein (GP) Ib-IX-V, mediates αIIbβ3 activation directly or through other signaling proteins physically associated with it (eg, FcR γ-chain), possibly with the contribution of other agonist receptors and of VWF signaling through αIIbβ3. To resolve this question, human and GP Ibα transgenic mouse platelets were plated on dimeric VWF A1 domain (dA1VWF), which engages only GP Ib-IX-V, in the presence of inhibitors of other agonist receptors. Platelet adhesion to dA1VWF induced Src kinase-dependent tyrosine phosphorylation of the FcR γ-chain and the adapter molecule, ADAP, and triggered intracellular Ca2+ oscillations and αIIbβ3 activation. Inhibition of Ca2+ oscillations with BAPTA-AM prevented αIIbβ3 activation but not tyrosine phosphorylation. Pharmacologic inhibition of protein kinase C (PKC) or phosphatidylinositol 3-kinase (PI 3-kinase) prevented αIIbβ3 activation but not Ca2+ oscillations. Inhibition of Src with 2 distinct compounds blocked all responses downstream of GP Ib-IX-V under static or flow conditions. However, dA1VWF-induced responses were reduced only slightly in GP Ibα transgenic platelets lacking FcR γ-chain. These data establish that GP Ib-IX-V itself can signal to activate αIIbβ3, through sequential actions of Src kinases, Ca2+ oscillations, and PI 3-kinase/PKC. (Blood. 2004;103:3403-3411)

Lack of Stability of Aggregates after Thrombin-Induced Reaggregation of Thrombin-Degranulated Platelets

1992 ◽  
Vol 67 (04) ◽  
pp. 453-457 ◽  
Author(s):  
Raelene L Kinlough-Rathbone ◽  
Marian A Packham ◽  
Dennis W Perry ◽  
J Fraser Mustard ◽  
Marco Cattaneo
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Rich Plasma ◽  
Thrombus Formation ◽  
Aggregate Stability ◽  
Relative Importance ◽  
Platelet Aggregates ◽  
The Stability ◽  
Von Willebrand ◽  
Induced Aggregation ◽  
Willebrand Factor

SummaryThe stability of platelet aggregates is influenced by the extent of the release of granule contents; if release is extensive and aggregation is prolonged, deaggregation is difficult to achieve. The relative importance of the contributions of released substances to aggregate stability are not known, although stable thrombin-induced aggregates form in platelet-rich plasma from patients with barely detectable plasma or platelet fibrinogen, and ADP stabilizes thrombin-induced aggregates of platelets from patients with delta storage pool deficiency which otherwise deaggregate more readily than normal platelets. We degranulated platelets with thrombin (0.9 U/ml caused greater than 90% loss of delta and alpha granule contents) and recovered them as individual platelets in fresh medium. The degranulated platelets were reaggregated by thrombin (2 U/ml). To prevent continuing effects of thrombin, FPRCH2C1 was added when thrombin-induced aggregation of thrombin-degranulated platelets reached its maximum. EDTA (5 mM) or EGTA (5 mM) added at maximum aggregation did not deaggregate these platelets, indicating that the stability of these aggregates does not depend on Ca2+ in the medium. Whereas with control platelets a combination of PGE1 (10 μM) and chymotrypsin(10 U/ml) was required for deaggregation, with thrombin-degranulated platelets either PGE1 or chymo-trypsin alone caused extensive deaggregation. The rate and extent of deaggregation of thrombin-degranulated platelets by a combination of PGE1 and chymotrypsin was greater than with control platelets.Electron microscope gold immunocytochemistry using antihuman fibrinogen IgG, anti-von Willebrand factor and anti-fibronectin showed a) that fibrinogen in the vacuoles of degranulated platelets was visible at focal points of platelet contact in the aggregates, but that large areas of platelet contact had no fibrinogen detectable between them; and b) in comparison to fibrinogen, little fibronectin or von Willebrand factor (vWf) was detectable in the platelets.Since the linkages between thrombin-degranulated platelets reaggregated by thrombin can be disrupted either by raising cAMP (thus making glycoprotein IIb/IIIa unavailable) or by proteolysis, these linkages are less stable than those formed between normal platelets. It might therefore be expected that platelets that take part in thrombus formation and then recirculate are likely to form less stable thrombi than platelets that have not released their granule contents.

scholarly journals Immunohistological Evaluation of Von Willebrand Factor in the Left Atrial Endocardium and Atrial Thrombi from Cats with Cardiomyopathy

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1240
Author(s):  
Wan-Ching Cheng ◽  
Lois Wilkie ◽  
Tsumugi Anne Kurosawa ◽  
Melanie Dobromylskyj ◽  
Simon Lawrence Priestnall ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Left Atrial ◽  
Thrombus Formation ◽  
Clinical Signs ◽  
Naturally Occurring ◽  
Feline Model ◽  
Von Willebrand ◽  
And Control ◽  
Endocardial Endothelium ◽  
Willebrand Factor

Aortic thromboembolism (ATE) occurs in cats with cardiomyopathy and often results in euthanasia due to poor prognosis. However, the underlying predisposing mechanisms leading to left atrial (LA) thrombus formation are not fully characterised. von Willebrand Factor (vWF) is a marker of endothelium and shows increased expression following endothelial injury. In people with poor LA function and LA remodelling, vWF has been implicated in the development of LA thrombosis. In this study we have shown (1) the expression of endocardial vWF protein detected using immunohistofluorescence was elevated in cats with cardiomyopathy, LA enlargement (LAE) and clinical signs compared to cats with subclinical cardiomyopathy and control cats; (2) vWF was present at the periphery of microthrombi and macrothrombi within the LA where they come into contact with the LA endocardium and (3) vWF was integral to the structure of the macrothrombi retrieved from the atria. These results provide evidence for damage of the endocardial endothelium in the remodelled LA and support a role for endocardial vWF as a pro-thrombotic substrate potentially contributing to the development of ATE in cats with underlying cardiomyopathy and LAE. Results from this naturally occurring feline model may inform research into human thrombogenesis.

scholarly journals Effect of aspirin on platelet-von Willebrand factor surface expression on thrombin and ADP-stimulated platelets

Blood ◽  
1989 ◽  
Vol 74 (6) ◽  
pp. 2016-2021 ◽  
Author(s):  
RI Parker ◽  
HR Gralnick
Keyword(s):  
Von Willebrand Factor ◽  
Shape Change ◽  
Adenosine Diphosphate ◽  
Surface Expression ◽  
Platelet Surface ◽  
Granule Secretion ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Platelet Shape ◽  
Stimulation Of

Abstract Platelets contain a pool of endogenous platelet-von Willebrand factor (vWF) that becomes expressed on the platelet surface when platelets are stimulated by a variety of agonists. Maximal platelet-vWF expression occurs in concert with platelet alpha-granule secretion. Aspirin (ASA) is known to impair platelet activation and alpha-granule secretion by irreversible inhibition of platelet cyclo-oxygenase. We studied native and ASA-treated platelets for their ability to mobilize and to express platelet-vWF in response to adenosine diphosphate (ADP) or thrombin. We found that each agonist was effective in promoting increased platelet- vWF surface expression on native and ASA-treated platelets. ASA-treated platelets responded identically to native platelets to low (0.01 U/mL) and high (1.0 U/mL) concentrations of thrombin, while the ADP-induced increase in ASA-treated platelets was only 50% to 60% of that for control platelets. Measurement of secreted platelet-vWF and beta- thromboglobulin indicated that the increase seen with ADP was largely independent of alpha-granule secretion. Using monoclonal antibodies (MoAbs) against the platelet glycoproteins (GP) IIb/IIIa and Ib (MoAbs 10E5 and 6D1, respectively), we demonstrated that the ADP-induced increase in platelet-vWF expression on control platelets primarily involved the binding of secreted platelet-vWF to the platelet GPIIb/IIIa. In contrast, the increase in platelet-vWF that occurred following ADP stimulation of ASA-treated platelets was largely insensitive to GPIIb/IIIa blockade. No effect of GPIb blockade in platelet-vWf expression was noted for either control or ASA-treated platelets. When platelet shape change was prevented by the addition of cytochalasin D, ADP-induced platelet-vWf surface expression on ASA- treated platelets was reduced by more than 80%. Our data indicate that platelets in which the cyclooxygenase pathway is blocked by the action of aspirin can increase surface expression of platelet-vWf as a consequence of platelet shape change. We speculate that this process exposes platelet-vWf bound to GPIIb/IIIa, or possibly GPIb, within the surface connected canalicular system.

Levels of von Willebrand factor and ADAMTS13 determine clinical outcome after cardioversion for atrial fibrillation

2011 ◽  
Vol 105 (03) ◽  
pp. 435-443 ◽  
Author(s):  
Veronika Bruno ◽  
Rudolf Jarai ◽  
Susanne Gruber ◽  
Thomas Höchtl ◽  
Ivan Brozovic ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Independent Predictor ◽  
Thrombus Formation ◽  
Critical Role ◽  
Inverse Correlation ◽  
Von Willebrand ◽  
Rhythm Stability ◽  
Willebrand Factor

SummaryVon Willebrand factor (vWF) plays an essential role in platelet adhesion and thrombus formation. Patients with atrial fibrillation (AF) exhibit higher plasma vWF and lower ADAMTS13 antigen levels compared to controls. Little is known about vWF and ADAMTS13 in AF patients treated with cardioversion (CV). Thus we investigated the alterations of plasma vWF and ADAMTS13 after CV and evaluated the predictive value of these parameters for recurrence of AF. In this observational study we determined plasma levels of vWF and ADAMTS13 in 77 patients before and immediately after CV, as well as 24 hours (h) and six weeks thereafter, by means of commercially available assays. The vWF/ ADAMTS13-ratio was significantly elevated immediately after CV (p=0.02) and 24 h after CV (p=0.002) as compared to baseline levels. ADAMTS13, 24 h after CV, exhibited a significant association with recurrence of AF (HR: 0.97; p=0.037). Accordingly, tertiles of ADAMTS13 showed a stepwise inverse correlation with the risk of recurrent AF (HR: 0.50; p=0.009). After adjustment for confounders, ADAMTS13 remained significant as an independent predictor of recurrent AF (HR: 0.61; p=0.047). Similarly, the vWF/ADAMTS13-ratio, 24 h after CV, was associated with rhythm stability and remained an independent predictor of recurrent AF (HR: 1.88; p=0.028). The regulation of vWF and its cleaving protease ADAMTS13 after CV might play a critical role in producing a pro-thrombotic milieu immediately after CV for AF. Since ADAMTS13 plasma concentration and the vWF/ADAMTS13-ratio are independently associated with rhythm stability, these indexes might be used for prediction of recurrence of AF.

Simulation of platelet adhesion and aggregation regulated by fibrinogen and von Willebrand factor

2008 ◽  
Vol 99 (01) ◽  
pp. 108-115 ◽  
Author(s):  
Koichiro Yano ◽  
Ken-ichi Tsubota ◽  
Takuji Ishikawa ◽  
Shigeo Wada ◽  
Takami Yamaguchi ◽  
...  
Keyword(s):  
Platelet Adhesion ◽  
Thrombus Formation ◽  
Simple Shear Flow ◽  
Stokesian Dynamics ◽  
General Observation ◽  
Significant Development ◽  
Platelet Adhesion And Aggregation ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryWe propose a method to analyze platelet adhesion and aggregation computationally, taking into account the distinct properties of two plasma proteins, vonWillebrand factor (vWF) and fibrinogen (Fbg). In this method, the hydrodynamic interactions between platelet particles under simple shear flow were simulated using Stokesian dynamics based on the additivity of velocities. The binding force between particles mediated by vWF and Fbg was modeled using the Voigt model. Two Voigt models with different properties were introduced to consider the distinct behaviors of vWF and Fbg. Our results qualitatively agreed with the general observation of a previous in-vitro experiment, thus demonstrating that the significant development of thrombus formation in height requires not only vWF, but also Fbg. This agreement of simulation and experimental results qualitatively validates our model and suggests that consideration of the distinct roles of vWF and Fbg is essential to investigate the physiological and pathophysiological mechanisms of thrombus formation using a computational approach.

Abstract 2641: Plasma Von Willebrand Factor and ADAMTS13 Concentrations in Atrial Fibrillation

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Takashi Uemura ◽  
Koichi Kaikita ◽  
Hiroshige Yamabe ◽  
Masakazu Matsukawa ◽  
Kenji Soejima ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Von Willebrand Factor ◽  
Left Atrial ◽  
Thrombus Formation ◽  
Significant Negative Correlation ◽  
Platelet Surface ◽  
Control Subjects ◽  
Number Of Patients ◽  
Von Willebrand ◽  
Willebrand Factor

Background : Von Willebrand factor (VWF) is released from damaged endothelium, and has a role in platelet aggregation through a receptor on the platelet surface. A metalloprotease that cleaves VWF multimers has been identified, namely, ADAMTS13. We recently reported that the serial changes in plasma VWF and ADAMTS13 antigen levels in patients with acute myocardial infarction (AMI), and that the VWF/ADAMTS13 ratio was a useful prognostic indicator of long-term thrombotic events after AMI. Although previous studies have shown raised plasma VWF in patients with atrial fibrillation (AF), little is known about the role of ADAMTS13 in the pathogenesis of AF. In the present study, we examined the relation between VWF and ADAMTS13 in AF patients. Methods and Results : We measured the plasma VWF and ADAMTS13 antigen levels by ELISA in 45 AF patients and 49 control subjects, and also performed echocardiography to examine the relations between these markers and left atrial or ventricular functions. The plasma VWF antigen levels were significantly higher in AF patients compared with controls (2017±749 vs. 1504±497 mU/ml, P=0.0002). In contrast, the plasma ADAMTS13 antigen levels were significantly lower in AF patients compared with controls (825±181 vs. 911±193 mU/ml, P=0.03). The VWF/ADAMTS13 ratio was significantly higher in AF patients compared with controls (2.59±1.20 vs. 1.75±0.76, P<0.0001). The number of patients who received aspirin and warfarin was significantly higher in AF group than control subjects, however, those medical therapy did not affect the VWF and ADAMTS13 antigen levels. There was significant positive correlation between VWF antigen levels and the left atrial dimension (n=128, r=0.228, P=0.0095). Furthermore, there was significant negative correlation between VWF antigen levels and the left atrial appendage peak flow velocity measured by transesophageal echocardiography (n=23, r=-0.611, p=0.0015). Conclusions : These findings suggest that the balance between VWF and ADAMTS13 levels may play an important role in the intra-atrial thrombus formation in AF patients. The present results would open a new therapeutic target for prevention of thromboembolic complications in AF.

«ADAMTS13 – VON WILLEBRAND FACTOR – PLATELETS» SYSTEM IN ATYPICAL HEMOLYTIC UREMIC SYNDROME IN CHILDREN

2021 ◽  
Vol 100 (4) ◽  
pp. 12-19
Author(s):  
Kh.М. Emirova ◽  
◽  
O.M. Orlova ◽  
E.M. Chichuga ◽  
А.L. Мuzurov ◽  
...  
Keyword(s):  
Hemolytic Uremic Syndrome ◽  
Von Willebrand Factor ◽  
Thrombus Formation ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Fluorescent Substrate ◽  
Uremic Syndrome ◽  
Von Willebrand ◽  
Willebrand Factor

Atypical hemolytic uremic syndrome (aHUS) is an orphan disease caused by hyperactivation of the alternative complement pathway. Objective of the study: to assess the state of the «ADAMTS13 – von Willebrand factor (vWF) – platelets» system in children with aHUS. Materials and methods of research: [by the FRET method (fluorescence resonance energy transfer) for the FRETSVWF73 (Peptide Institude, Inc., Japan)] hydrolysis of the fluorescent substrate and ADAMTS13 antigen [by ELISA using TECHNOZYM® ADAMTS13 5450551 ELISA (Technoclone GmbH, Austria)], vWF activity [for platelet agglutination (aggregation) in the presence of ristomycin (NPO Renam reagent kit for the ALAT-230LA-2 aggregometer, Russia)] and vWF antigen [by ELISA using the TECHNOZYM® vWF kit: Ag 5450201 ELISA (Technoclone GmbH , Austria)]. Results: there was a decrease in the activity and concentration of ADAMTS13 in 63% and 62% of patients, respectively. A decrease in vWF activity was noted in 44% of cases, an increase in its concentration – in 54% of children. Thrombocytopenia was diagnosed in 99% of children. Conclusion: the imbalance in the «ADAMTS13 – vWF – platelets» system supports the process of thrombus formation with the development of organ ischemia in aHUS under conditions of endothelial dysfunction. Reduced ADAMTS13 activity predicts the severity of the disease.

Computational Mechanical Analysis of the Platelets Behavior in the Blood Flow Using Discrete Element Method

2000 ◽  
Author(s):  
Hisako Miyazaki ◽  
Hao Liu ◽  
Takami Yamaguchi
Keyword(s):  
Blood Flow ◽  
Vessel Wall ◽  
Thrombus Formation ◽  
Mechanical Analysis ◽  
Soluble Form ◽  
Blood Constituents ◽  
Fibrin Network ◽  
Insoluble Form ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Platelets play an important role in blood coagulation, particularly in the formation of primary thrombi. It is thought that the aggregation of platelets, which initiates primary thrombi formation, is mediated by a macromolecule called von Willebrand Factor (vWF). vWF is a long chain macromolecule that exists in the blood flow as a soluble form and in the vessel wall as an insoluble form. Figure 1 schematically shows normal (a) and pathological (b) thrombus formation processes as illustrated by Ikeda (1998) In both cases, platelets adhere to the injured vessel wall and then form a thrombus in cooperation with the fibrin network, red cells, and other blood constituents. vWF is thought to play a more important role in pathological thrombosis formation than in the normal hemostatic process, particularly due to its ability to react to hemodynamic stress.

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