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Swinkels M, Hordijk S, Bürgisser PE, Slotman JA, Carter T, Leebeek FWG, Jansen AJG, Voorberg J, Bierings R. Quantitative super-resolution imaging of platelet degranulation reveals differential release of von Willebrand factor and von Willebrand factor propeptide from alpha-granules. J Thromb Haemost 2023; 21:1967-1980. [PMID: 37061132 DOI: 10.1016/j.jtha.2023.03.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 03/10/2023] [Accepted: 03/31/2023] [Indexed: 04/17/2023]
Abstract
BACKGROUND Von Willebrand factor (VWF) and VWF propeptide (VWFpp) are stored in eccentric nanodomains within platelet alpha-granules. VWF and VWFpp can undergo differential secretion following Weibel-Palade body exocytosis in endothelial cells; however, it is unclear if the same process occurs during platelet alpha-granule exocytosis. Using a high-throughput 3-dimensional super-resolution imaging workflow for quantification of individual platelet alpha-granule cargo, we studied alpha-granule cargo release in response to different physiological stimuli. OBJECTIVES To investigate how VWF and VWFpp are released from alpha-granules in response to physiological stimuli. METHODS Platelets were activated with protease-activated receptor 1 (PAR-1) activating peptide (PAR-1 ap) or collagen-related peptide (CRP-XL). Alpha-tubulin, VWF, VWFpp, secreted protein acidic and cysteine rich (SPARC), and fibrinogen were imaged using 3-dimensional structured illumination microscopy, followed by semiautomated analysis in FIJI. Uptake of anti-VWF nanobody during degranulation was used to identify alpha-granules that partially released content. RESULTS VWFpp overlapped with VWF in eccentric alpha-granule subdomains in resting platelets and showed a higher degree of overlap with VWF than SPARC or fibrinogen. Activation of PAR-1 (0.6-20 μM PAR-1 ap) or glycoprotein VI (GPVI) (0.25-1 μg/mL CRP-XL) signaling pathways caused a dose-dependent increase in alpha-granule exocytosis. More than 80% of alpha-granules remained positive for VWF, even at the highest agonist concentrations. In contrast, the residual fraction of alpha-granules containing VWFpp decreased in a dose-dependent manner to 23%, whereas SPARC and fibrinogen were detected in 60% to 70% of alpha-granules when stimulated with 20 μM PAR-1 ap. Similar results were obtained using CRP-XL. Using an extracellular anti-VWF nanobody, we identified VWF in postexocytotic alpha-granules. CONCLUSION We provide evidence for differential secretion of VWF and VWFpp from individual alpha-granules.
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Affiliation(s)
- Maurice Swinkels
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. https://twitter.com/MauriceSwinkels
| | - Sophie Hordijk
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. https://twitter.com/sophiehordijk
| | - Petra E Bürgisser
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Johan A Slotman
- Optical Imaging Center, Department of Pathology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Tom Carter
- Molecular and Clinical Sciences Research Institute, St George's University of London, London, United Kingdom
| | - Frank W G Leebeek
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - A J Gerard Jansen
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jan Voorberg
- Molecular Hematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Experimental Vascular Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ruben Bierings
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
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Ward SE, O'Sullivan JM, Moran AB, Spencer DIR, Gardner RA, Sharma J, Fazavana J, Monopoli M, McKinnon TAJ, Chion A, Haberichter S, O'Donnell JS. Sialylation on O-linked glycans protects von Willebrand factor from macrophage galactose lectin-mediated clearance. Haematologica 2022; 107:668-679. [PMID: 33763999 PMCID: PMC8883566 DOI: 10.3324/haematol.2020.274720] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 03/12/2021] [Indexed: 11/17/2022] Open
Abstract
Terminal sialylation determines the plasma half-life of von Willebrand factor (VWF). A role for macrophage galactose lectin (MGL) in regulating hyposialylated VWF clearance has recently been proposed. In this study, we showed that MGL influences physiological plasma VWF clearance. MGL inhibition was associated with a significantly extended mean residence time and 3-fold increase in endogenous plasma VWF antigen levels (P<0.05). Using a series of VWF truncations, we further demonstrated that the A1 domain of VWF is predominantly responsible for enabling the MGL interaction. Binding of both full-length and VWF-A1-A2-A3 to MGL was significantly enhanced in the presence of ristocetin (P<0.05), suggesting that the MGL-binding site in A1 is not fully accessible in globular VWF. Additional studies using different VWF glycoforms demonstrated that VWF O-linked glycans, clustered at either end of the A1 domain, play a key role in protecting VWF against MGLmediated clearance. Reduced sialylation has been associated with pathological, increased clearance of VWF in patients with von Willebrand disease. Herein, we demonstrate that specific loss of α2-3 linked sialylation from O-glycans results in markedly increased MGL-binding in vitro, and markedly enhanced MGL-mediated clearance of VWF in vivo. Our data further show that the asialoglycoprotein receptor (ASGPR) does not have a significant role in mediating the increased clearance of VWF following loss of O-sialylation. Conversely however, we observed that loss of N-linked sialylation from VWF drives enhanced circulatory clearance predominantly via the ASGPR. Collectively, our data support the hypothesis that in addition to regulating physiological VWF clearance, the MGL receptor works in tandem with ASGPR to modulate enhanced clearance of aberrantly sialylated VWF in the pathogenesis of von Willebrand disease.
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Affiliation(s)
- Soracha E Ward
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland
| | - Jamie M O'Sullivan
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland
| | - Alan B Moran
- Ludger, Ltd., Culham Science Centre, Abingdon, Oxfordshire OX14 3EB, United Kingdom; Leiden University Medical Centre, Centre for Proteomics and Metabolomics, 2300 RC Leiden
| | | | | | - Jyotika Sharma
- Department of Basic Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota
| | - Judicael Fazavana
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland
| | - Marco Monopoli
- Department of Chemistry, RCSI, 123 St. Stephen's Green, Dublin 2
| | - Thomas A J McKinnon
- Faculty of Medicine, Imperial College, Hammersmith Hospital, Ducane Road, London
| | - Alain Chion
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland
| | | | - James S O'Donnell
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland; National Children's Research Centre, Our Lady's Children's Hospital, Dublin, Ireland; National Coagulation Centre, St James's Hospital, Dublin.
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Kragh T, Pekrul I, Ott HW, Spannagl M, Möhnle P. A novel approach to laboratory assessment and reporting of platelet von Willebrand factor. Platelets 2021; 33:242-248. [PMID: 33427003 DOI: 10.1080/09537104.2020.1869715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The interaction of platelets with von Willebrand factor is essential for primary hemostasis. Concentration and activity of plasma von Willebrand factor are routine parameters in the assessment of hemostasis disorders. In addition to plasma von Willebrand factor, platelet von Willebrand factor, synthesized in megakaryocytes and stored in α-granules of circulating platelets, is known to contribute to primary hemostasis and the microenvironment of thrombus formation. The laboratory assessment of platelet von Willebrand factor however is cumbersome and not widely established as a routine parameter. We here propose a method for laboratory assessment and reporting of platelet von Willebrand factor potentially useful for laboratory routines in specialized laboratories. Our model allows to describe platelet von Willebrand factor as 1. the concentration of platelet von Willebrand factor in whole blood, 2. the amount of platelet von Willebrand factor in a sample with a defined concentration of 1000 platelets/nl, and 3. the concentration of platelet von Willebrand factor in one platelet. According to our results in healthy individuals, the proportion of platelet von Willebrand factor activity is estimated to be about 10% of total von Willebrand factor in human plasma under physiological circumstances. The concentration of platelet von Willebrand factor is estimated to be 0.4 IU/ml in a sample with a defined concentration of 1000 platelets/nl and to be about 42 IU/ml in one platelet (both expressed as VWF:Ag).
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Affiliation(s)
- Thorsten Kragh
- Department of Transfusion Medicine, Cell Therapeutics and Haemostaseology, LMU Klinikum, München, Germany
| | - Isabell Pekrul
- Department of Transfusion Medicine, Cell Therapeutics and Haemostaseology, LMU Klinikum, München, Germany.,Department of Anaesthesiology, LMU Klinikum, München, Germany
| | | | - Michael Spannagl
- Department of Transfusion Medicine, Cell Therapeutics and Haemostaseology, LMU Klinikum, München, Germany
| | - Patrick Möhnle
- Department of Transfusion Medicine, Cell Therapeutics and Haemostaseology, LMU Klinikum, München, Germany
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Ward S, O'Sullivan JM, O'Donnell JS. von Willebrand factor sialylation-A critical regulator of biological function. J Thromb Haemost 2019; 17:1018-1029. [PMID: 31055873 DOI: 10.1111/jth.14471] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/24/2019] [Indexed: 12/29/2022]
Abstract
Essentials Von Willebrand Factor (VWF) is extensively glycosylated with serial studies demonstrating that these carbohydrate determinants play critical roles in regulating multiple aspects of VWF biology. Terminal sialic acid residues, expressed on both the N- and O-linked glycans of VWF, regulate VWF functional activity, susceptibility to proteolysis and plasma clearance in vivo. Quantitative and qualitative variations in VWF sialylation have been reported in patients with von Willebrand Disease, as well as in a number of other physiological and pathological states. Further studies are warranted to define the molecular mechanisms through which N- and O-linked sialylation impacts upon the multiple biological activities of VWF. von Willebrand factor (VWF) undergoes complex post-translational modification prior to its secretion into the plasma. Consequently, VWF monomers contain complex N-glycan and O-glycan structures that, together, account for approximately 20% of the final monomeric mass. An increasing body of evidence has confirmed that these carbohydrate determinants play critical roles in regulating multiple aspects of VWF biology. In particular, studies have demonstrated that terminal ABO blood group has an important effect on plasma VWF levels. This effect is interesting, given that only 15% of the N-glycans and 1% of the O-glycans of VWF actually express terminal ABO(H) determinants. In contrast, the vast majority of the N-glycans and O-glycans on human VWF are capped by terminal negatively charged sialic acid residues. Recent data suggest that sialylation significantly regulates VWF functional activity, susceptibility to proteolysis, and clearance, through a number of independent pathways. These findings are of direct clinical relevence, in that quantitative and qualitative variations in VWF sialylation have been described in patients with VWD, as well as in patients with a number of other physiologic and pathologic conditions. Moreover, platelet-derived VWF is significantly hyposialylated as compared with plasma-derived VWF, whereas the recently licensed recombinant VWF therapeutic is hypersialylated. In this review, we examine the evidence supporting the hypothesis that VWF sialylation plays multiple biological roles. In addition, we consider data suggesting that quantitative and qualitative variations in VWF sialylation may play specific roles in the pathogenesis of VWD, and that sialic acid expression on VWF may also differ across a number of other physiologic and pathologic conditions.
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Affiliation(s)
- Soracha Ward
- Haemostasis Research Group, Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jamie M O'Sullivan
- Haemostasis Research Group, Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - James S O'Donnell
- Haemostasis Research Group, Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
- National Coagulation Centre, St James's Hospital, Dublin, Ireland
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Tsai HM. Thrombotic Thrombocytopenic Purpura and Hemolytic-Uremic Syndromes. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00042-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Riddell A, Vinayagam S, Gomez K, Laffan M, McKinnon T. Evaluation of von Willebrand factor concentrates by platelet adhesion to collagen using an in vitro flow assay. Res Pract Thromb Haemost 2019; 3:126-135. [PMID: 30656286 PMCID: PMC6332833 DOI: 10.1002/rth2.12166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 10/19/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Von Willebrand disease (VWD) results from quantitative or qualitative deficiency of von Willebrand factor (VWF) and is treated using VWF-containing concentrates. Several studies have compared the function of various VWF containing concentrates however this has not been performed using shear based assays. OBJECTIVES To compare the platelet-capture potential of 10 commercially available, plasma-derived VWF concentrates under shear conditions. METHODS VWF containing concentrates were assessed for VWF:Ag, VWF:CB, VWF:RCo, factor VIII:C ADAMTS13 content, VWF multimeric profile and glycan content using lectin binding assays. Free-thiol content of each concentrate was investigated using MPB binding assays. An in vitro flow assay was used to determine the ability of each concentrate to mediate platelet capture to collagen. RESULTS VWF multimeric analysis revealed reduction of high molecular weight (HMW) forms in four of the concentrates (Alphante, Octanate and Haemoctin, and 8Y). The high MW multimer distribution of the remaining six concentrates (Optivate, Wilate, Fandhi, Wilfactin, Haemate P, and Voncento) was similar to the plasma control. Lectin analysis demonstrated that 8Y had increased amount of T-antigen. Although platelet capture after 5 minutes perfusion was similar for all concentrates; Alphante, Octanate, and Haemoctin, demonstrated the lowest levels of platelet capture after 60 seconds of perfusion. Free-thiol content and ADAMTS13 levels varied widely between the concentrates but was not correlated with function. CONCLUSION Alphanate, Octanate, and Haemoctin, lacked HMW multimers and had the lowest initial platelet capture levels suggesting that the presence of VWF HMW multimers are required for initial platelet deposition.
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Affiliation(s)
- Anne Riddell
- Katharine Dormandy Haemophilia Centre and Thrombosis UnitRoyal Free London NHS Foundation TrustLondonUK
| | - Saravanan Vinayagam
- Katharine Dormandy Haemophilia Centre and Thrombosis UnitRoyal Free London NHS Foundation TrustLondonUK
| | - Keith Gomez
- Katharine Dormandy Haemophilia Centre and Thrombosis UnitRoyal Free London NHS Foundation TrustLondonUK
| | - Mike Laffan
- Department of HaematologyImperial College of Science Technology and MedicineLondonUK
| | - Tom McKinnon
- Department of HaematologyImperial College of Science Technology and MedicineLondonUK
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Doddapattar P, Dhanesha N, Chorawala MR, Tinsman C, Jain M, Nayak MK, Staber JM, Chauhan AK. Endothelial Cell-Derived Von Willebrand Factor, But Not Platelet-Derived, Promotes Atherosclerosis in Apolipoprotein E-Deficient Mice. Arterioscler Thromb Vasc Biol 2018; 38:520-528. [PMID: 29348121 DOI: 10.1161/atvbaha.117.309918] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 01/08/2018] [Indexed: 12/31/2022]
Abstract
OBJECTIVE VWF (von Willebrand factor) is synthesized by endothelial cells and megakaryocytes and is known to contribute to atherosclerosis. In vitro studies suggest that platelet-derived VWF (Plt-VWF) is biochemically and functionally different from endothelial cell-derived VWF (EC-VWF). We determined the role of different pools of VWF in the pathophysiology of atherosclerosis. APPROACH AND RESULTS Using bone marrow transplantation, we generated chimeric Plt-VWF, EC-VWF, and Plt-VWF mice lacking a disintegrin and metalloprotease with thrombospondin type I repeats-13 in platelets and plasma on apolipoprotein E-deficient (Apoe-/-) background. Controls were chimeric Apoe-/- mice transplanted with bone marrow from Apoe-/- mice (wild type) and Vwf-/-Apoe-/- mice transplanted with bone marrow from Vwf-/-Apoe-/- mice (VWF-knock out). Susceptibility to atherosclerosis was evaluated in whole aortae and cross-sections of the aortic sinus in female mice fed a high-fat Western diet for 14 weeks. VWF-knock out, Plt-VWF, and Plt-VWF mice lacking a disintegrin and metalloprotease with thrombospondin type I repeats-13 exhibited reduced plaque size characterized by smaller necrotic cores, reduced neutrophil and monocytes/macrophages content, decreased MMP9 (matrix metalloproteinase), MMP2, and CX3CL1 (chemokine [C-X3-C motif] ligand 1)-positive area, and abundant interstitial collagen (P<0.05 versus wild-type or EC-VWF mice). Atherosclerotic lesion size and composition were comparable between wild-type or EC-VWF mice. Together these findings suggest that EC-VWF, but not Plt-VWF, promotes atherosclerosis exacerbation. Furthermore, intravital microscopy experiments revealed that EC-VWF, but not Plt-VWF, contributes to platelet and leukocyte adhesion under inflammatory conditions at the arterial shear rate. CONCLUSIONS EC-VWF, but not Plt-VWF, contributes to VWF-dependent atherosclerosis by promoting platelet adhesion and vascular inflammation. Plt-VWF even in the absence of a disintegrin and metalloprotease with thrombospondin type I repeats-13, both in platelet and plasma, was not sufficient to promote atherosclerosis.
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Affiliation(s)
- Prakash Doddapattar
- From the Department of Internal Medicine (P.D., N.D., M.R.C., M.J., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (C.T., J.M.S.), University of Iowa, Iowa City
| | - Nirav Dhanesha
- From the Department of Internal Medicine (P.D., N.D., M.R.C., M.J., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (C.T., J.M.S.), University of Iowa, Iowa City
| | - Mehul R Chorawala
- From the Department of Internal Medicine (P.D., N.D., M.R.C., M.J., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (C.T., J.M.S.), University of Iowa, Iowa City
| | - Chandler Tinsman
- From the Department of Internal Medicine (P.D., N.D., M.R.C., M.J., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (C.T., J.M.S.), University of Iowa, Iowa City
| | - Manish Jain
- From the Department of Internal Medicine (P.D., N.D., M.R.C., M.J., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (C.T., J.M.S.), University of Iowa, Iowa City
| | - Manasa K Nayak
- From the Department of Internal Medicine (P.D., N.D., M.R.C., M.J., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (C.T., J.M.S.), University of Iowa, Iowa City
| | - Janice M Staber
- From the Department of Internal Medicine (P.D., N.D., M.R.C., M.J., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (C.T., J.M.S.), University of Iowa, Iowa City
| | - Anil K Chauhan
- From the Department of Internal Medicine (P.D., N.D., M.R.C., M.J., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (C.T., J.M.S.), University of Iowa, Iowa City.
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Brehm MA. Von Willebrand factor processing. Hamostaseologie 2016; 37:59-72. [PMID: 28139814 DOI: 10.5482/hamo-16-06-0018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 11/03/2016] [Indexed: 11/05/2022] Open
Abstract
Von Willebrand factor (VWF) is a multimeric glycoprotein essential for primary haemostasis that is produced only in endothelial cells and megakaryocytes. Key to VWF's function in recruitment of platelets to the site of vascular injury is its multimeric structure. The individual steps of VWF multimer biosynthesis rely on distinct posttranslational modifications at specific pH conditions, which are realized by spatial separation of the involved processes to different cell organelles. Production of multimers starts with translocation and modification of the VWF prepropolypeptide in the endoplasmic reticulum to produce dimers primed for glycosylation. In the Golgi apparatus they are further processed to multimers that carry more than 300 complex glycan structures functionalized by sialylation, sulfation and blood group determinants. Of special importance is the sequential formation of disulfide bonds with different functions in structural support of VWF multimers, which are packaged, stored and further processed after secretion. Here, all these processes are being reviewed in detail including background information on the occurring biochemical reactions.
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Affiliation(s)
- Maria A Brehm
- PD Dr. Maria A. Brehm, Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 22399 Hamburg, Germany, Tel.: +49 40 7410 58523, Fax: +49 40 7410 54601, E-Mail:
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Diagnostic Value of Measuring Platelet Von Willebrand Factor in Von Willebrand Disease. PLoS One 2016; 11:e0161310. [PMID: 27532107 PMCID: PMC4988781 DOI: 10.1371/journal.pone.0161310] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/03/2016] [Indexed: 11/19/2022] Open
Abstract
Von Willebrand disease (VWD) may be caused by an impaired von Willebrand factor (VWF) synthesis, its increased clearance or abnormal function, or combinations of these factors. It may be difficult to recognize the different contributions of these anomalies. Here we demonstrate that VWD diagnostics gains from measuring platelet VWF, which can reveal a defective VWF synthesis. Measuring platelet VWF revealed that: severe type 1 VWD always coincided with significantly lower platelet and plasma VWF levels, whereas mild forms revealed low plasma VWF levels associated with low or normal platelet VWF levels, and the latter were associated with a slightly shorter VWF survival; type Vicenza (the archetype VWD caused by a reduced VWF survival) featured normal platelet VWF levels despite significantly reduced plasma VWF levels; type 2B patients could have either normal platelet VWF levels associated with abnormal multimer patterns, or reduced platelet VWF levels associated with normal multimer patterns; type 2A patients could have reduced or normal platelet VWF levels, the former associated mainly with type 2A-I, the latter with type 2A-II; plasma and platelet VWF levels were normal in type 2N, except when the defect was associated with a quantitative VWF mutation. Our findings show that measuring platelet VWF helps to characterize VWD, especially the ambiguous phenotypes, shedding light on the mechanisms underlying the disorder.
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Dhanesha N, Prakash P, Doddapattar P, Khanna I, Pollpeter MJ, Nayak MK, Staber JM, Chauhan AK. Endothelial Cell-Derived von Willebrand Factor Is the Major Determinant That Mediates von Willebrand Factor-Dependent Acute Ischemic Stroke by Promoting Postischemic Thrombo-Inflammation. Arterioscler Thromb Vasc Biol 2016; 36:1829-37. [PMID: 27444201 DOI: 10.1161/atvbaha.116.307660] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/11/2016] [Indexed: 01/01/2023]
Abstract
OBJECTIVE von Willebrand factor (VWF), which is synthesized in endothelial cells and megakaryocytes, is known to worsen stroke outcome. In vitro studies suggest that platelet-derived VWF (Plt-VWF) is biochemically different from the endothelial cell-derived VWF (EC-VWF). However, little is known about relative contribution of different pools of VWF in stroke. APPROACH AND RESULTS Using bone marrow transplantation, we generated chimeric Plt-VWF mice, Plt-VWF mice that lack ADAMTS13 in platelets and plasma (Plt-VWF/Adamts13(-/-)), and EC-VWF mice to determine relative contribution of different pools of VWF in stroke. In brain ischemia/reperfusion injury model, we found that infarct size and postischemic intracerebral thrombo-inflammation (fibrin(ogen) deposition, neutrophil infiltration, interleukin-1β, and tumor necrosis factor-α levels) within lesions were comparable between EC-VWF and wild-type mice. Infarct size and postischemic thrombo-inflammation were comparable between Plt-VWF and Plt-VWF/Adamts13(-/-) mice, but decreased compared with EC-VWF and wild-type mice (P<0.05) and increased compared with Vwf(-/-) mice (P<0.05). Susceptibility to FeCl3 injury-induced carotid artery thrombosis was comparable between wild-type and EC-VWF mice, whereas Plt-VWF and Plt-VWF/Adamts13(-/-) mice exhibited defective thrombosis. Although most of the injured vessels did not occlude, slope over time showed that thrombus growth rate was increased in both Plt-VWF and Plt-VWF/Adamts13(-/-) mice compared with Vwf(-/-) mice (P<0.05), but decreased compared with wild-type or EC-VWF mice. CONCLUSIONS Plt-VWF, either in presence or absence of ADAMTS13, partially contributes to VWF-dependent injury and postischemic thrombo-inflammation after stroke. EC-VWF is the major determinant that mediates VWF-dependent ischemic stroke by promoting postischemic thrombo-inflammation.
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Affiliation(s)
- Nirav Dhanesha
- From the Department of Internal Medicine (N.D., P.P., P.D., I.K., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (M.J.P., J.M.S.), University of Iowa, Iowa City
| | - Prem Prakash
- From the Department of Internal Medicine (N.D., P.P., P.D., I.K., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (M.J.P., J.M.S.), University of Iowa, Iowa City
| | - Prakash Doddapattar
- From the Department of Internal Medicine (N.D., P.P., P.D., I.K., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (M.J.P., J.M.S.), University of Iowa, Iowa City
| | - Ira Khanna
- From the Department of Internal Medicine (N.D., P.P., P.D., I.K., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (M.J.P., J.M.S.), University of Iowa, Iowa City
| | - Molly J Pollpeter
- From the Department of Internal Medicine (N.D., P.P., P.D., I.K., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (M.J.P., J.M.S.), University of Iowa, Iowa City
| | - Manasa K Nayak
- From the Department of Internal Medicine (N.D., P.P., P.D., I.K., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (M.J.P., J.M.S.), University of Iowa, Iowa City
| | - Janice M Staber
- From the Department of Internal Medicine (N.D., P.P., P.D., I.K., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (M.J.P., J.M.S.), University of Iowa, Iowa City
| | - Anil K Chauhan
- From the Department of Internal Medicine (N.D., P.P., P.D., I.K., M.K.N., A.K.C.) and Stead Family Department of Pediatrics (M.J.P., J.M.S.), University of Iowa, Iowa City.
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Shahidi M. Thrombosis and von Willebrand Factor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 906:285-306. [DOI: 10.1007/5584_2016_122] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Platelet-derived VWF is not essential for normal thrombosis and hemostasis but fosters ischemic stroke injury in mice. Blood 2015. [PMID: 26209660 DOI: 10.1182/blood-2015-03-632901] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Von Willebrand factor (VWF) is a key hemostatic protein synthesized in both endothelial cells and megakaryocytes. Megakaryocyte-derived VWF is stored in α-granules of platelets and is enriched in hyperactive "ultra-large" VWF multimers. To elucidate the specific contribution of platelet VWF in hemostasis and thrombosis, we performed crossed bone marrow transplantations between C57BL/6J and Vwf(-/-) mice to generate chimeric mice. Chimeric mice specifically lacking platelet VWF showed normal tail bleeding and carotid artery thrombosis, similar to wild-type mice. Chimeric mice with VWF present only in platelets were not able to support normal thrombosis and hemostasis. However, using a mouse model of transient middle cerebral artery occlusion, we observed that cerebral infarct sizes and fibrin(ogen) deposition in chimeric mice with only platelet VWF were significantly increased compared with Vwf(-/-) mice (P < .01). Blocking of the platelet VWF-glycoprotein (GP)Ib interaction abrogated this platelet VWF-mediated injury. These data suggest that whereas platelet-derived VWF does not play a crucial role in hemostasis and arterial thrombosis, it aggravates thrombo-inflammatory diseases such as stroke via a GPIb-dependent mechanism.
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Shi Q, Schroeder JA, Kuether EL, Montgomery RR. The important role of von Willebrand factor in platelet-derived FVIII gene therapy for murine hemophilia A in the presence of inhibitory antibodies. J Thromb Haemost 2015; 13:1301-9. [PMID: 25955153 PMCID: PMC4496307 DOI: 10.1111/jth.13001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/16/2015] [Indexed: 12/01/2022]
Abstract
BACKGROUND Our previous studies have demonstrated that targeting FVIII expression to platelets results in FVIII storage together with von Willebrand factor (VWF) in platelet α-granules and that platelet-derived FVIII (2bF8) corrects the murine hemophilia A phenotype even in the presence of high-titer anti-FVIII inhibitory antibodies (inhibitors). OBJECTIVE To explore how VWF has an impact on platelet gene therapy for hemophilia A with inhibitors. METHODS 2bF8 transgenic mice in the FVIII(-/-) background (2bF8(tg+/-) F8(-/-) ) with varying VWF phenotypes were used in this study. Animals were analyzed by VWF ELISA, FVIII activity assay, Bethesda assay and tail clip survival test. RESULTS Only 18% of 2bF8(tg+/-) F8(-/-) VWF(-/-) animals, in which VWF was deficient, survived the tail clip challenge with inhibitor titers of 3-8000 BU mL(-1) . In contrast, 82% of 2bF8(tg+/-) F8(-/-) VWF(+/+) mice, which had normal VWF levels, survived tail clipping with inhibitor titers of 10-50,000 BU mL(-1) . All 2bF8(tg+/-) F8(-/-) VWF(-/-) mice without inhibitors survived tail clipping and no VWF(-/-) F8(-/-) mice survived this challenge. Because VWF is synthesized by endothelial cells and megakaryocytes and is distributed in both plasma and platelets in peripheral blood, we further investigated the effect of each compartment of VWF on platelet-FVIII gene therapy for hemophilia A with inhibitors. In the presence of inhibitors, 42% of animals survived tail clipping in the group with plasma-VWF and 50% survived in the platelet-VWF group. CONCLUSION VWF is essential for platelet gene therapy for hemophilia A with inhibitors. Both platelet-VWF and plasma-VWF are required for optimal platelet-derived FVIII gene therapy for hemophilia A in the presence of inhibitors.
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Affiliation(s)
- Q Shi
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Blood Research Institute, Blood Center of Wisconsin, Milwaukee, WI, USA
- Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI, USA
- MACC Fund Research Center, Milwaukee, WI, USA
| | - J A Schroeder
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Blood Research Institute, Blood Center of Wisconsin, Milwaukee, WI, USA
- Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI, USA
| | - E L Kuether
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Blood Research Institute, Blood Center of Wisconsin, Milwaukee, WI, USA
- Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI, USA
| | - R R Montgomery
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Blood Research Institute, Blood Center of Wisconsin, Milwaukee, WI, USA
- Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI, USA
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Abstract
In this issue of Blood, McGrath et al show that the terminal glycan structures of platelet von Willebrand factor (VWF) are markedly different compared with such structures present on plasma VWF.1 Unexpectedly, these differences endow platelet VWF with a specific resistance against proteolysis by the VWF-cleaving protease ADAMTS13, thereby potentially increasing the hemostatic potential of platelet VWF during the formation of platelet-rich thrombi.
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Altered glycosylation of platelet-derived von Willebrand factor confers resistance to ADAMTS13 proteolysis. Blood 2013; 122:4107-10. [DOI: 10.1182/blood-2013-04-496851] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Key Points
Platelet-VWF exists as a distinct natural glycoform. Platelet-VWF is resistant to ADAMTS13 proteolysis.
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Berntorp E, Fuchs B, Makris M, Montgomery R, Flood V, O'Donnell JS, Federici AB, Lillicrap D, James P, Budde U, Morfini M, Petrini P, Austin S, Kannicht C, Jiménez-Yuste V, Lee C. Third Åland islands conference on von Willebrand disease, 26-28 September 2012: meeting report. Haemophilia 2013; 19 Suppl 3:1-18. [PMID: 23383607 DOI: 10.1111/hae.12078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2012] [Indexed: 01/03/2023]
Abstract
The first meeting of international specialists in the field of von Willebrand disease (VWD) was held in the Åland islands in 1998 where Erik von Willebrand had first observed a bleeding disorder in some members of a family from Föglö and a summary of the meeting was published in 1999. The second meeting was held in 2010 and a report of the meeting was published in 2012. Topics covered included progress in understanding of VWD over the last 50 years; multimers; classification of VWD; pharmacokinetics and laboratory assays; genetics; treating the paediatric patient; prophylaxis; geriatrics; gene therapy and treatment guidelines. This third meeting held over 3 days covered the structure and function of von Willebrand factor (VWF); type 1 VWD, the most common form of the disease; a lifespan of pharmacokinetics in VWD; detecting inhibitors in VWD patients; and special challenges in understanding and treating the female VWD patient.
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Affiliation(s)
- E Berntorp
- Department of Hematology and Coagulation Disorders, Lund University, Skåne University Hospital, Malmö, Sweden.
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17
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Tsai HM. Thrombotic Thrombocytopenic Purpura and the Hemolytic-Uremic Syndrome. Platelets 2013. [DOI: 10.1016/b978-0-12-387837-3.00043-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kanaji S, Fahs SA, Shi Q, Haberichter SL, Montgomery RR. Contribution of platelet vs. endothelial VWF to platelet adhesion and hemostasis. J Thromb Haemost 2012; 10:1646-52. [PMID: 22642380 PMCID: PMC3419786 DOI: 10.1111/j.1538-7836.2012.04797.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND von Willebrand factor (VWF) is a glycoprotein that plays an important role in primary hemostasis. VWF is synthesized and stored in endothelial cells (ECs) and megakaryocytes/platelets. Plasma VWF is primarily derived from ECs and is generally believed to be essential for hemostasis. VWF synthesized in megakaryocytes is stored in platelet α-granules, from which it is released following platelet activation. The relative contribution of VWF stored in ECs or megakaryocytes/platelets or present in plasma to hemostasis is not clear. OBJECTIVES We investigated whether EC-derived VWF plays the major role in hemostasis while the contribution of platelet-derived VWF is negligible, or if platelet-derived VWF also significantly contributes to hemostasis. METHODS AND RESULTS Mice expressing VWF only in ECs (EC-VWF) or platelets (Plt-VWF) were created by reciprocal bone marrow transplantation between C57BL/6J (WT) and VWF knockout mice (VWF-/-). Plasma VWF levels in EC-VWF were similar to WT. Plt-VWF mice had a trace amount of VWF in their plasma while VWF levels in platelet lysate were comparable to WT. Tail bleeding time was normal in EC-VWF. Interestingly, Plt-VWF showed partially corrected bleeding time and significantly decreased blood loss volume compared with VWF-/-. Adhesion of platelets perfused over immobilized collagen under shear stress was significantly higher in both EC-VWF and Plt-VWF compared with VWF-/-. CONCLUSION VWF synthesized in ECs is sufficient to support hemostasis in VWF-/- mice, and VWF produced in megakaryocytes/platelets can also contribute to hemostasis in the absence of EC-derived VWF.
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Affiliation(s)
- S Kanaji
- Blood Research Institute, BloodCenter of Wisconsin, Department of Pediatrics, Medical College of Wisconsin, Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA.
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McGrath RT, McRae E, Smith OP, O’Donnell JS. Platelet von Willebrand factor - structure, function and biological importance. Br J Haematol 2010; 148:834-43. [DOI: 10.1111/j.1365-2141.2009.08052.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Liu L, Choi H, Bernardo A, Bergeron AL, Nolasco L, Ruan C, Moake JL, Dong JF. Platelet-derived VWF-cleaving metalloprotease ADAMTS-13. J Thromb Haemost 2005; 3:2536-44. [PMID: 16176307 DOI: 10.1111/j.1538-7836.2005.01561.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The adhesion ligand von Willebrand factor (VWF) is synthesized and stored in vascular endothelial cells and megakaryocytes/platelets. As in endothelial cells, platelet VWF also contains ultra-large (UL) multimers that are hyperactive in aggregating platelets. ULVWF in platelet lysates of thrombin-stimulated platelets was only detected in the presence of EDTA, suggesting that ULVWF is cleaved by a divalent cation-dependent protease. A recent study shows that platelets contain the VWF-cleaving metalloprotease ADAMTS-13, but its activity remains unknown. In this study, we show that platelet lysates cleave endothelial cell-derived ULVWF under static and flow conditions. This activity is inhibited by EDTA and by an ADAMTS-13 antibody from the plasma of a patient with acquired TTP. ADAMTS-13 was detected in platelet lysates and on the platelet surface by four antibodies that bind to different domains of the metalloprotease. Expression of ADAMTS-13 on the platelet surface increases significantly upon platelet activation by the thrombin receptor-activating peptide, but not by ADP. These results demonstrate that platelets contain functionally active ADAMTS-13. This intrinsic activity may be physiologically important to prevent the sudden release of hyperactive ULVWF from platelets and serves as the second pool of ADAMTS-13 to encounter the increase in ULVWF release from endothelial cells.
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Affiliation(s)
- L Liu
- Department of Medicine, Thrombosis Research Section, Baylor College of Medicine, Houston, TX 77030, USA
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Abstract
Snake venom toxins affecting haemostasis have facilitated extensively the routine assays of haemostatic parameters in the coagulation laboratory. Snake venom thrombin-like enzymes (SVTLE) are used for fibrinogen/fibrinogen breakdown product assay and for the detection of fibrinogen dysfunction. SVTLE are not inhibited by heparin and can thus can be used for assaying antithrombin III and other haemostatic variables in heparin-containing samples. Snake venoms are a rich source of prothrombin activators and these are utilised in prothrombin assays, for studying dysprothrombinaemias and for preparing meizothrombin and non-enzymic forms of prothrombin. Russell's viper (Daboia russelli) venom (RVV) contains toxins which have been used to assay blood clotting factors V, VII, X, platelet factor 3 and, importantly, lupus anticoagulants (LA). Other prothrombin activators (from the taipan, Australian brown snake and saw-scaled viper) have now been used to assay LA. Protein C and activated protein C resistance can be measured by means of RVV and Protac, a fast acting inhibitor from Southern copperhead snake venom and von Willebrand factor can be studied with botrocetin from Bothrops jararaca venom. The disintegrins, a large family of Arg-Gly-Asp (RGD)-containing snake venom proteins, show potential for studying platelet glycoprotein receptors, notably, GPIIb/IIIa and Ib. Snake venom toxins affecting haemostasis are also used in the therapeutic setting: Ancrod (from the Malayan pit viper, Calloselasma rhodostoma), in particular, has been used as an anticoagulant to achieve 'therapeutic defibrination'. Other snake venom proteins show promise in the treatment of a range of haemostatic disorders.
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Abstract
AbstractShear-induced binding of von Willebrand factor (vWf) to the platelet glycoprotein (GP) Ib/V/IX complex plays a key role in initiating platelet adhesion and aggregation at sites of vascular injury. This study demonstrated that pretreating human platelets with inhibitors of actin polymerization, cytochalasin D or latrunculin B, dramatically enhances platelet aggregation induced by vWf. The effects of these inhibitors were specific to the vWf-GPIbα interaction because they enhanced vWf-induced aggregation of Glanzmann thrombasthenic platelets and Chinese hamster ovary (CHO) cells transfected with GPIb/V/IX. Moreover, cytochalasin D enhanced the extent of platelet aggregation induced by high shear stress (5000 s−1) and also lowered the shear threshold required to induce aggregation from 3000 s−1 to as low as 500 s−1. Studies of CHO cells expressing GPIbα cytoplasmic tail truncation mutants that failed to bind actin-binding protein-280 (deletion of residues 569-610 or 535-568) demonstrated that the linkage between GPIb and actin-binding protein-280 was not required for vWf-induced actin polymerization, but was critical for the enhancing effects of cytochalasin D on vWf-induced cell aggregation. Taken together, these studies suggest a fundamentally important role for the cytoskeleton in regulating the adhesive function of GPIb/V/IX.
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Abstract
Shear-induced binding of von Willebrand factor (vWf) to the platelet glycoprotein (GP) Ib/V/IX complex plays a key role in initiating platelet adhesion and aggregation at sites of vascular injury. This study demonstrated that pretreating human platelets with inhibitors of actin polymerization, cytochalasin D or latrunculin B, dramatically enhances platelet aggregation induced by vWf. The effects of these inhibitors were specific to the vWf-GPIbα interaction because they enhanced vWf-induced aggregation of Glanzmann thrombasthenic platelets and Chinese hamster ovary (CHO) cells transfected with GPIb/V/IX. Moreover, cytochalasin D enhanced the extent of platelet aggregation induced by high shear stress (5000 s−1) and also lowered the shear threshold required to induce aggregation from 3000 s−1 to as low as 500 s−1. Studies of CHO cells expressing GPIbα cytoplasmic tail truncation mutants that failed to bind actin-binding protein-280 (deletion of residues 569-610 or 535-568) demonstrated that the linkage between GPIb and actin-binding protein-280 was not required for vWf-induced actin polymerization, but was critical for the enhancing effects of cytochalasin D on vWf-induced cell aggregation. Taken together, these studies suggest a fundamentally important role for the cytoskeleton in regulating the adhesive function of GPIb/V/IX.
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Sarode R, Goldstein J, Sussman II, Nagel RL, Tsai HM. Role of A and B blood group antigens in the expression of adhesive activity of von Willebrand factor. Br J Haematol 2000; 109:857-64. [PMID: 10929042 DOI: 10.1046/j.1365-2141.2000.02113.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABO (H) blood group antigens are covalently linked to the oligosaccharide side-chains of von Willebrand factor (VWF). In this study, we investigated the role of the A and B antigens in the expression of VWF adhesive activity. VWF of type A, B or O was purified from fresh frozen plasma. Presence of A or B antigen on the VWF was confirmed by enzyme-linked immunosorbent assay (ELISA) and by immunoblotting with monoclonal anti-A or anti-B. The A or B antigen was also detected in the 48/52-kDa fragment of the respective VWF after trypsin digestion. Removal of A antigen with alpha-N-acetylgalactosaminidase or B antigen with alpha-galactosidase did not affect its multimer size or antigenic level, but decreased the ristocetin cofactor (RCoF) activity of the respective VWF by 33-39% (P < 0.01-0.002). Removal of A or B antigen from VWF did not affect the binding of the VWF to immobilized type III collagen. A and B antigens were not detected in platelet VWF. These results indicate that AB structures play a role in platelet aggregating activity of VWF.
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Affiliation(s)
- R Sarode
- Department of Pathology, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, OH 44106, USA.
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Kulkarni S, Dopheide SM, Yap CL, Ravanat C, Freund M, Mangin P, Heel KA, Street A, Harper IS, Lanza F, Jackson SP. A revised model of platelet aggregation. J Clin Invest 2000; 105:783-91. [PMID: 10727447 PMCID: PMC377457 DOI: 10.1172/jci7569] [Citation(s) in RCA: 251] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In this study we have examined the mechanism of platelet aggregation under physiological flow conditions using an in vitro flow-based platelet aggregation assay and an in vivo rat thrombosis model. Our studies demonstrate an unexpected complexity to the platelet aggregation process in which platelets in flowing blood continuously tether, translocate, and/or detach from the luminal surface of a growing platelet thrombus at both arterial and venous shear rates. Studies of platelets congenitally deficient in von Willebrand factor (vWf) or integrin alpha(IIb)beta(3) demonstrated a key role for platelet vWf in mediating platelet tethering and translocation, whereas integrin alpha(IIb)beta(3) mediated cell arrest. Platelet aggregation under flow appears to be a multistep process involving: (a) exposure of vWf on the surface of immobilized platelets; (b) a reversible phase of platelet aggregation mediated by the binding of GPIbalpha on the surface of free-flowing platelets to vWf on the surface of immobilized platelets; and (c) an irreversible phase of aggregation dependent on integrin alpha(IIb)beta(3). Studies of platelet thrombus formation in vivo demonstrate that this multistep adhesion mechanism is indispensable for platelet aggregation in arterioles and also appears to promote platelet aggregate formation in venules. Together, our studies demonstrate an important role for platelet vWf in initiating the platelet aggregation process under flow and challenge the currently accepted view that the vWf-GPIbalpha interaction is exclusively involved in initiating platelet aggregation at elevated shear rates.
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Affiliation(s)
- S Kulkarni
- Australian Centre for Blood Diseases, Department of Medicine, Monash Medical School, Box Hill Hospital, Box Hill, Victoria 3128, Australia
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Mannucci PM. Platelet von Willebrand factor in inherited and acquired bleeding disorders. Proc Natl Acad Sci U S A 1995; 92:2428-32. [PMID: 7708659 PMCID: PMC42231 DOI: 10.1073/pnas.92.7.2428] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- P M Mannucci
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, IRCCS Maggiore Hospital, Milan, Italy
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