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Liu H, Welburn JPI. A circle of life: platelet and megakaryocyte cytoskeleton dynamics in health and disease. Open Biol 2024; 14:240041. [PMID: 38835242 DOI: 10.1098/rsob.240041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 04/24/2024] [Indexed: 06/06/2024] Open
Abstract
Platelets are blood cells derived from megakaryocytes that play a central role in regulating haemostasis and vascular integrity. The microtubule cytoskeleton of megakaryocytes undergoes a critical dynamic reorganization during cycles of endomitosis and platelet biogenesis. Quiescent platelets have a discoid shape maintained by a marginal band composed of microtubule bundles, which undergoes remarkable remodelling during platelet activation, driving shape change and platelet function. Disrupting or enhancing this process can cause platelet dysfunction such as bleeding disorders or thrombosis. However, little is known about the molecular mechanisms underlying the reorganization of the cytoskeleton in the platelet lineage. Recent studies indicate that the emergence of a unique platelet tubulin code and specific pathogenic tubulin mutations cause platelet defects and bleeding disorders. Frequently, these mutations exhibit dominant negative effects, offering valuable insights into both platelet disease mechanisms and the functioning of tubulins. This review will highlight our current understanding of the role of the microtubule cytoskeleton in the life and death of platelets, along with its relevance to platelet disorders.
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Affiliation(s)
- Haonan Liu
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Julie P I Welburn
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
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2
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Loss of α4A- and β1-tubulins leads to severe platelet spherocytosis and strongly impairs hemostasis in mice. Blood 2022; 140:2290-2299. [PMID: 36026602 DOI: 10.1182/blood.2022016729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 08/16/2022] [Indexed: 11/20/2022] Open
Abstract
Native circulating blood platelets present with a discoid flat morphology maintained by a submembranous peripheral ring of microtubules, named marginal band. The functional importance of this particular shape is still debated, but it was initially hypothesized to facilitate platelet interaction with the injured vessel wall and to contribute to hemostasis. The importance of the platelet discoid morphology has since been questioned on the absence of clear bleeding tendency in mice lacking the platelet-specific β1-tubulin isotype, which exhibits platelets with a thinner marginal band and an ovoid shape. Here, we generated a mouse model inactivated for β1-tubulin and α4A-tubulin, an α-tubulin isotype strongly enriched in platelets. These mice present with fully spherical platelets completely devoid of a marginal band. In contrast to the single knockouts, the double deletion resulted in a severe bleeding defect in a tail-clipping assay, which was not corrected by increasing the platelet count to normal values by the thrombopoietin-analog romiplostim. In vivo, thrombus formation was almost abolished in a ferric chloride-injury model, with only a thin layer of loosely packed platelets, and mice were protected against death in a model of thromboembolism. In vitro, platelets adhered less efficiently and formed smaller-sized and loosely assembled aggregates when perfused over von Willebrand factor and collagen matrices. In conclusion, this study shows that blood platelets require 2 unique α- and β-tubulin isotypes to acquire their characteristic discoid morphology. Lack of these 2 isotypes has a deleterious effect on flow-dependent aggregate formation and stability, leading to a severe bleeding disorder.
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4
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Bourguignon A, Tasneem S, Hayward CP. Screening and diagnosis of inherited platelet disorders. Crit Rev Clin Lab Sci 2022; 59:405-444. [PMID: 35341454 DOI: 10.1080/10408363.2022.2049199] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Inherited platelet disorders are important conditions that often manifest with bleeding. These disorders have heterogeneous underlying pathologies. Some are syndromic disorders with non-blood phenotypic features, and others are associated with an increased predisposition to developing myelodysplasia and leukemia. Platelet disorders can present with thrombocytopenia, defects in platelet function, or both. As the underlying pathogenesis of inherited thrombocytopenias and platelet function disorders are quite diverse, their evaluation requires a thorough clinical assessment and specialized diagnostic tests, that often challenge diagnostic laboratories. At present, many of the commonly encountered, non-syndromic platelet disorders do not have a defined molecular cause. Nonetheless, significant progress has been made over the past few decades to improve the diagnostic evaluation of inherited platelet disorders, from the assessment of the bleeding history to improved standardization of light transmission aggregometry, which remains a "gold standard" test of platelet function. Some platelet disorder test findings are highly predictive of a bleeding disorder and some show association to symptoms of prolonged bleeding, surgical bleeding, and wound healing problems. Multiple assays can be required to diagnose common and rare platelet disorders, each requiring control of preanalytical, analytical, and post-analytical variables. The laboratory investigations of platelet disorders include evaluations of platelet counts, size, and morphology by light microscopy; assessments for aggregation defects; tests for dense granule deficiency; analyses of granule constituents and their release; platelet protein analysis by immunofluorescent staining or flow cytometry; tests of platelet procoagulant function; evaluations of platelet ultrastructure; high-throughput sequencing and other molecular diagnostic tests. The focus of this article is to review current methods for the diagnostic assessment of platelet function, with a focus on contemporary, best diagnostic laboratory practices, and relationships between clinical and laboratory findings.
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Affiliation(s)
- Alex Bourguignon
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Subia Tasneem
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Catherine P Hayward
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada.,Department of Medicine, McMaster University, Hamilton, Canada
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6
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Chen D, Uhl CB, Bryant SC, Krumwiede M, Barness RL, Olson MC, Gossman SC, Erdogan Damgard S, Gamb SI, Cummins LA, Charlesworth JE, Wood-Wentz CM, Salisbury JL, Plumhoff EA, Van Cott EM, He R, Warad DM, Pruthi RK, Heit JA, Nichols WL, White JG. Diagnostic laboratory standardization and validation of platelet transmission electron microscopy. Platelets 2018; 29:574-582. [PMID: 29863946 DOI: 10.1080/09537104.2018.1476682] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Platelet transmission electron microscopy (PTEM) is considered the gold standard test for assessing distinct ultrastructural abnormalities in inherited platelet disorders (IPDs). Nevertheless, PTEM remains mainly a research tool due to the lack of standardized procedures, a validated dense granule (DG) count reference range, and standardized image interpretation criteria. The aim of this study was to standardize and validate PTEM as a clinical laboratory test. Based on previously established methods, we optimized and standardized preanalytical, analytical, and postanalytical procedures for both whole mount (WM) and thin section (TS) PTEM. Mean number of DG/platelet (plt), percentage of plts without DG, platelet count (PC), mean platelet volume (MPV), immature platelet fraction (IPF), and plt light transmission aggregometry analyses were measured on blood samples from 113 healthy donors. Quantile regression was used to estimate the reference range for DG/plt, and linear regression was used to assess the association of DG/plt with other plt measurements. All PTEM procedures were standardized using commercially available materials and reagents. DG interpretation criteria were established based on previous publications and expert consensus, and resulted in improved operator agreement. Mean DG/plt was stable for 2 days after blood sample collection. The median within patient coefficient of variation for mean DG/plt was 22.2%; the mean DG/plt reference range (mid-95th %) was 1.2-4.0. Mean DG/plt was associated with IPF (p = .01, R2 = 0.06) but not age, sex, PC, MPV, or plt maximum aggregation or primary slope of aggregation (p > .17, R2 < 0.02). Baseline ultrastructural features were established for TS-PTEM. PTEM was validated using samples from patients with previously established diagnoses of IPDs. Standardization and validation of PTEM procedures and interpretation, and establishment of the normal mean DG/plt reference range and PTEM baseline ultrastructural features, will facilitate implementation of PTEM as a valid clinical laboratory test for evaluating ultrastructural abnormalities in IPDs.
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Affiliation(s)
- Dong Chen
- a Division of Hematopathology , Mayo Clinic , Rochester , Minnesota , USA
| | - Cindy B Uhl
- b Electron Microscope Core Facility , Mayo Clinic , Rochester , Minnesota , USA
| | - Sandra C Bryant
- c Division of Biomedical Statistics and Informatics , Mayo Clinic , Rochester , Minnesota , USA
| | - Marcy Krumwiede
- d Departments of Laboratory Medicine, Pathology, and Pediatrics , University of Minnesota School of Medicine , Minneapolis , Minnesota , USA
| | - Ryan L Barness
- b Electron Microscope Core Facility , Mayo Clinic , Rochester , Minnesota , USA
| | - Mary C Olson
- b Electron Microscope Core Facility , Mayo Clinic , Rochester , Minnesota , USA
| | - Susan C Gossman
- b Electron Microscope Core Facility , Mayo Clinic , Rochester , Minnesota , USA
| | | | - Scott I Gamb
- b Electron Microscope Core Facility , Mayo Clinic , Rochester , Minnesota , USA
| | - Lisa A Cummins
- b Electron Microscope Core Facility , Mayo Clinic , Rochester , Minnesota , USA
| | - Jon E Charlesworth
- b Electron Microscope Core Facility , Mayo Clinic , Rochester , Minnesota , USA
| | - Christina M Wood-Wentz
- c Division of Biomedical Statistics and Informatics , Mayo Clinic , Rochester , Minnesota , USA
| | - Jeffrey L Salisbury
- b Electron Microscope Core Facility , Mayo Clinic , Rochester , Minnesota , USA
| | | | - Elizabeth M Van Cott
- e Department of Pathology , Massachusetts General Hospital, Harvard Medical School , Boston , Massachusetts , USA
| | - Rong He
- a Division of Hematopathology , Mayo Clinic , Rochester , Minnesota , USA
| | - Deepti M Warad
- a Division of Hematopathology , Mayo Clinic , Rochester , Minnesota , USA
| | - Rajiv K Pruthi
- a Division of Hematopathology , Mayo Clinic , Rochester , Minnesota , USA
| | - John A Heit
- a Division of Hematopathology , Mayo Clinic , Rochester , Minnesota , USA
| | - William L Nichols
- a Division of Hematopathology , Mayo Clinic , Rochester , Minnesota , USA
| | - James G White
- d Departments of Laboratory Medicine, Pathology, and Pediatrics , University of Minnesota School of Medicine , Minneapolis , Minnesota , USA
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7
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Litvinenko A, Moskalensky A, Karmadonova N, Nekrasov V, Strokotov D, Konokhova A, Yurkin M, Pokushalov E, Chernyshev A, Maltsev V. Fluorescence-free flow cytometry for measurement of shape index distribution of resting, partially activated, and fully activated platelets. Cytometry A 2016; 89:1010-1016. [DOI: 10.1002/cyto.a.23003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 09/01/2016] [Accepted: 10/05/2016] [Indexed: 11/11/2022]
Affiliation(s)
- A.L. Litvinenko
- Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk Russian Federation
- Novosibirsk State University; Novosibirsk Russian Federation
| | - A.E. Moskalensky
- Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk Russian Federation
- Novosibirsk State University; Novosibirsk Russian Federation
| | - N.A. Karmadonova
- State Research Institute of Circulation Pathology; Novosibirsk Russian Federation
| | - V.M. Nekrasov
- Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk Russian Federation
- Novosibirsk State University; Novosibirsk Russian Federation
| | - D.I. Strokotov
- Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk Russian Federation
- Novosibirsk State Medical University; Novosibirsk Russian Federation
| | - A.I. Konokhova
- Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk Russian Federation
| | - M.A. Yurkin
- Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk Russian Federation
- Novosibirsk State University; Novosibirsk Russian Federation
| | - E.A. Pokushalov
- State Research Institute of Circulation Pathology; Novosibirsk Russian Federation
| | - A.V. Chernyshev
- Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk Russian Federation
- Novosibirsk State University; Novosibirsk Russian Federation
| | - V.P. Maltsev
- Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk Russian Federation
- Novosibirsk State University; Novosibirsk Russian Federation
- Novosibirsk State Medical University; Novosibirsk Russian Federation
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Infante AA, Infante D, Chan MC, How PC, Kutschera W, Linhartová I, Müllner EW, Wiche G, Propst F. Ferritin associates with marginal band microtubules. Exp Cell Res 2007; 313:1602-14. [PMID: 17391669 DOI: 10.1016/j.yexcr.2007.02.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2006] [Revised: 02/06/2007] [Accepted: 02/08/2007] [Indexed: 10/23/2022]
Abstract
We characterized chicken erythrocyte and human platelet ferritin by biochemical studies and immunofluorescence. Erythrocyte ferritin was found to be a homopolymer of H-ferritin subunits, resistant to proteinase K digestion, heat stable, and contained iron. In mature chicken erythrocytes and human platelets, ferritin was localized at the marginal band, a ring-shaped peripheral microtubule bundle, and displayed properties of bona fide microtubule-associated proteins such as tau. Red blood cell ferritin association with the marginal band was confirmed by temperature-induced disassembly-reassembly of microtubules. During erythrocyte differentiation, ferritin co-localized with coalescing microtubules during marginal band formation. In addition, ferritin was found in the nuclei of mature erythrocytes, but was not detectable in those of bone marrow erythrocyte precursors. These results suggest that ferritin has a function in marginal band formation and possibly in protection of the marginal band from damaging effects of reactive oxygen species by sequestering iron in the mature erythrocyte. Moreover, our data suggest that ferritin and syncolin, a previously identified erythrocyte microtubule-associated protein, are identical. Nuclear ferritin might contribute to transcriptional silencing or, alternatively, constitute a ferritin reservoir.
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Affiliation(s)
- Anthony A Infante
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT 06459, USA
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Hayward CPM, Rao AK, Cattaneo M. Congenital platelet disorders: overview of their mechanisms, diagnostic evaluation and treatment. Haemophilia 2006; 12 Suppl 3:128-36. [PMID: 16684008 DOI: 10.1111/j.1365-2516.2006.01270.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bleeding problems associated with common and rare inherited platelet disorders illustrate the importance of platelets to normal haemostasis. At sites of injury, platelets normally adhere, undergo activation, secretion and aggregate formation, and they provide the membrane surface for the assembly of coagulation to generate thrombin. The causes of inherited disorders that alter platelet haemostatic functions are quite diverse, ranging from defects in receptors critical to platelet adhesion and aggregation, to defects in signalling molecules or in transcription factors important for production of functional platelets. The mechanisms of impaired platelet function are largely unknown for the more common disorders that alter platelet activation, secretion and the secondary wave of platelet aggregation. The diagnostic evaluation of congenital platelet disorders has been challenging as some 'platelet-type' bleeding symptoms, such as bruising, are quite common in the general population. Moreover, the diagnostic tests used by clinical laboratories to evaluate disorders of platelet function have not been standardized. In individuals recognized to have an inherited defect in platelet function, therapy is important for controlling and preventing bleeding episodes. Presently, there are a number of choices to consider for the management of bleeding symptoms, including menorrhagia. This paper reviews the causes, diagnostic evaluation and therapies for common and rare congenital platelet disorders.
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Freson K, De Vos R, Wittevrongel C, Thys C, Defoor J, Vanhees L, Vermylen J, Peerlinck K, Van Geet C. The TUBB1 Q43P functional polymorphism reduces the risk of cardiovascular disease in men by modulating platelet function and structure. Blood 2005; 106:2356-62. [PMID: 15956286 DOI: 10.1182/blood-2005-02-0723] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The discoid form of platelets is maintained by a marginal band of tightly coiled microtubules. beta1-tubulin is the major isoform within platelet and megakaryocyte microtubules. In 24.2% of 33 unrelated inherited macrothrombocytopenia patients and in 10.6% of 272 subjects of a healthy population a P for Q substitution in beta1-tubulin was found in the highly conserved residue 43. Heterozygous carriers of the Q43P variant showed a reduced platelet protein beta1-tubulin expression. Transfection of green fluorescent protein (GFP)-tagged Q43P beta1-tubulin in megakaryocytic MEG01 cells resulted in a disturbed tubulin organization. Electron microscopy revealed enlarged spherocytic platelets with a disturbed marginal band and organelle-free zones. In addition, platelets with the Q43P beta1-tubulin variant had reduced adenosine triphosphate (ATP) secretion, thrombin receptor activating peptide (TRAP)-induced aggregation and collagen adhesion. The prevalence of the Q43P beta1-tubulin variant was also 2 times higher (odds ratio, [OR] = 2.1;95% confidence interval [CI], 1.22-3.59) among control subjects than among patients with cardiovascular disease (10.4% versus 5.2%, P < .001). By analyzing this protective factor in men and women separately, this association was only found in men. This study thus presents the functional consequences of the platelet Q43P beta1-tubulin substitution that is frequent in the healthy population and may protect men against arterial thrombosis.
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Affiliation(s)
- Kathleen Freson
- Center for Molecular and Vascular Biology, Department of Pathology, Cardiovascular Rehabilitation Unit, University of Leuven, Belgium.
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