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Weber S, Arnold JBZ, Sachs UJ, Luppa PB. Recombinantly Expressed Tagged SUrface Protein (RETSUP) assay: a new diagnostic system for the detection of antibodies to platelets. J Thromb Haemost 2024; 22:1187-1201. [PMID: 38184205 DOI: 10.1016/j.jtha.2023.12.030] [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: 10/26/2023] [Revised: 12/11/2023] [Accepted: 12/28/2023] [Indexed: 01/08/2024]
Abstract
BACKGROUND Current assays for the detection of (allo)antibodies to platelet antigens are often laborious and widely based on the presence of well-characterized donor platelets. OBJECTIVES To develop an easy-to-perform, sensitive, and specific test for the detection of antibodies against platelet antigens, in particular, glycoprotein (GP) antigens, called "Recombinantly Expressed Tagged SUrface Protein" (RETSUP) assay, which does not require donor platelets. METHODS Twin-Strep-tagged GP complexes were recombinantly expressed in human embryonic kidney 293 cells after stable transfection. These cell lines were used as antigen sources in the RETSUP assay, combining cell-based and enzyme-linked immunosorbent assay-based assay procedures. The assay performance was tested with recombinant antibodies, anti-human platelet antigen (HPA) reference plasmas, and anti-HPA patient sera. RESULTS Human embryonic kidney 293 cell lines stably expressing either Twin-Strep-labeled GPIa/IIa, GPIIb/IIIa, GPIb/IX, or GPIb/IX/V complexes or GPV as well as the distinct HPA-1, HPA-3, and HPA-5 epitopes were successfully generated. Applying the generated GP-expressing cell lines, the developed RETSUP assay proved very sensitive and specific with recombinant antibodies targeting different GPs and human plasma/serum samples. The results of the test were not affected by the GP carrying the Twin-Strep-tag or by using freshly harvested or cryopreserved cells. CONCLUSION The RETSUP assay is an easy-to-perform, sensitive, and specific assay for the detection of plasma/serum antibodies to platelet GP, with performance comparable to or better than those of current state-of-the-art assays in antiplatelet antibody diagnostics. Owing to the recombinant nature of the target antigens, it can be easily adapted to detect antibodies in other antibody-mediated diseases.
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Affiliation(s)
- Susanne Weber
- Institute of Clinical Chemistry and Pathobiochemistry, Klinikum rechts der Isar of the Technische Universität München, Munich, Germany.
| | - Jasmin Birgit Zuzana Arnold
- Institute of Clinical Chemistry and Pathobiochemistry, Klinikum rechts der Isar of the Technische Universität München, Munich, Germany
| | - Ulrich Jörg Sachs
- Institute for Clinical Immunology, Transfusion Medicine, and Haemostasis, Justus Liebig University, Giessen, Germany; Department of Thrombosis and Haemostasis, Giessen University Hospital, Giessen, Germany
| | - Peter Bruno Luppa
- Institute of Clinical Chemistry and Pathobiochemistry, Klinikum rechts der Isar of the Technische Universität München, Munich, Germany
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Garzon Dasgupta AK, Martyanov AA, Ignatova AA, Zgoda VG, Novichkova GA, Panteleev MA, Sveshnikova AN. Comparison of platelet proteomic profiles between children and adults reveals origins of functional differences. Pediatr Res 2024; 95:966-973. [PMID: 37872237 DOI: 10.1038/s41390-023-02865-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/25/2023] [Accepted: 09/26/2023] [Indexed: 10/25/2023]
Abstract
BACKGROUND Platelets are blood cells responsible for the prevention of blood loss upon vessel wall disruption. It has been demonstrated that platelet functioning differs significantly between adult and pediatric donors. This study aimed to identify potential differences between the protein composition of platelets of pediatric, adolescent, and adult donors. METHODS Platelet functional testing was conducted with live cell flow cytometry. Using a straightforward approach to platelet washing based on the sequential platelets centrifugation-resuspension, we were able to obtain stable and robust proteomics results, which corresponded to previously published data. RESULTS We have identified that pediatric donors' platelets have increased amounts of proteins, responsible for mitochondrial activity, proteasome activity, and vesicle transport. Flow cytometry analysis of platelet intracellular signaling and functional responses revealed that platelets of the pediatric donors have diminished granule secretion and increased quiescent platelet calcium concentration and decreased calcium mobilization in response to ADP. We could explain the observed changes in calcium responses by the increased mitochondria protein content, and the changes in granule secretion could be explained by the differences in vesicle transport protein content. CONCLUSIONS Therefore, we can conclude that the age-dependence of platelet functional responses originates from the difference in platelet protein content. IMPACT Platelets of infants are known to functionally differ from the platelet of adult donors, although the longevity and persistivity of these differences are debatable. Pediatric donor platelets have enhanced amounts of mitochondrial, proteasomal, and vesicle transport proteins. Platelets of the pediatric donors had increased cytosolic calcium in the resting state, what is explained by the increased numbers of mitochondrial proteins. Infants had decreased platelet granule release, which resolved upon adolescence. Thus, platelets of the infants should be assessed differently from adult platelets. Differences in platelet proteomic contents persisted in adolescent groups, yet, no significant differences in platelet function were observed.
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Affiliation(s)
- Andrei K Garzon Dasgupta
- Center for Theoretical Problems of Physico-Сhemical Pharmacology, Russian Academy of Sciences, 30 Srednyaya Kalitnikovskaya str., Moscow, 109029, Russia
| | - Alexey A Martyanov
- Center for Theoretical Problems of Physico-Сhemical Pharmacology, Russian Academy of Sciences, 30 Srednyaya Kalitnikovskaya str., Moscow, 109029, Russia
- National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology named after Dmitry Rogachev, 1 Samory Mashela St, Moscow, 117198, Russia
| | - Anastasia A Ignatova
- Center for Theoretical Problems of Physico-Сhemical Pharmacology, Russian Academy of Sciences, 30 Srednyaya Kalitnikovskaya str., Moscow, 109029, Russia
- National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology named after Dmitry Rogachev, 1 Samory Mashela St, Moscow, 117198, Russia
| | - Victor G Zgoda
- Institute of Biomedical Chemistry, 10 bld. 8, Pogodinskaya str., 119121, Moscow, Russia
| | - Galina A Novichkova
- National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology named after Dmitry Rogachev, 1 Samory Mashela St, Moscow, 117198, Russia
| | - Mikhail A Panteleev
- Center for Theoretical Problems of Physico-Сhemical Pharmacology, Russian Academy of Sciences, 30 Srednyaya Kalitnikovskaya str., Moscow, 109029, Russia
- National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology named after Dmitry Rogachev, 1 Samory Mashela St, Moscow, 117198, Russia
- Lomonosov Moscow State University, 1/2 Leninskie gory, Moscow, 119991, Russia
| | - Anastasia N Sveshnikova
- Center for Theoretical Problems of Physico-Сhemical Pharmacology, Russian Academy of Sciences, 30 Srednyaya Kalitnikovskaya str., Moscow, 109029, Russia.
- National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology named after Dmitry Rogachev, 1 Samory Mashela St, Moscow, 117198, Russia.
- Lomonosov Moscow State University, 1/2 Leninskie gory, Moscow, 119991, Russia.
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3
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Lu J, Zhang C, Shi S, Li S, Liu J, Wu J, Huang C, Lei M. Stoichiometry and architecture of the platelet membrane complex glycoprotein Ib-IX-V. Biol Chem 2024; 405:91-104. [PMID: 36942505 DOI: 10.1515/hsz-2022-0227] [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: 07/12/2022] [Accepted: 03/06/2023] [Indexed: 03/23/2023]
Abstract
Glycoprotein (GP) Ib-IX-V is the second most abundant platelet receptor for thrombin and other ligands crucial for hemostasis and thrombosis. Its activity is involved in platelet adhesion to vascular injury sites and thrombin-induced platelet aggregation. GPIb-IX-V is a heteromeric complex composed of four subunits, GPIbα, GPIbβ, GPV and GPIX, in a stoichiometric ratio that has been wildly debated. Despite its important physiological roles, the overall structure and molecular arrangement of GPIb-IX-V are not yet fully understood. Here, we purify stable and functional human GPIb-IX-V complex from reconstituted EXPi293F cells in high homogeneity, and perform biochemical and structural characterization of this complex. Single-particle cryo-electron microscopy structure of GPIb-IX-V is determined at ∼11 Å resolution, which unveils the architecture of GPIb-IX-V and its subunit organization. Size-exclusion chromatography-multi-angle static light scattering analysis reveals that GPIb-IX-V contains GPIb-IX and GPV at a 1:1 stoichiometric ratio and surface plasmon resonance assays show that association of GPV leads to slow kinetics of thrombin binding to GPIb-IX-V. Taken together, our results provide the first three-dimensional architecture of the intact GPIb-IX-V complex, which extends our understanding of the structure and functional mechanism of this complex in hemostasis and thrombosis.
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Affiliation(s)
- Juanjuan Lu
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Chunli Zhang
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Shaohua Shi
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Shaobai Li
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Junling Liu
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Wu
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Chenhui Huang
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Ming Lei
- Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
- State Key laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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4
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陶 人, 谢 旭, 吴 建, 方 颖. [Molecular dynamics simulation of force-regulated interaction between glycoprotein Ib α and filamin]. SHENG WU YI XUE GONG CHENG XUE ZA ZHI = JOURNAL OF BIOMEDICAL ENGINEERING = SHENGWU YIXUE GONGCHENGXUE ZAZHI 2023; 40:876-885. [PMID: 37879916 PMCID: PMC10600417 DOI: 10.7507/1001-5515.202302043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 06/06/2023] [Indexed: 10/27/2023]
Abstract
In resting platelets, the 17 th domain of filamin a (FLNa17) constitutively binds to the platelet membrane glycoprotein Ibα (GPIbα) at its cytoplasmic tail (GPIbα-CT) and inhibits the downstream signal activation, while the binding of ligand and blood shear force can activate platelets. To imitate the pull force transmitted from the extracellular ligand of GPIbα and the lateral tension from platelet cytoskeleton deformation, two pulling modes were applied on the GPIbα-CT/FLNa17 complex, and the molecular dynamics simulation method was used to explore the mechanical regulation on the affinity and mechanical stability of the complex. In this study, at first, nine pairs of key hydrogen bonds on the interface between GPIbα-CT and FLNa17 were identified, which was the basis for maintaining the complex structural stability. Secondly, it was found that these hydrogen bonding networks would be broken down and lead to the dissociation of FLNa17 from GPIbα-CT only under the axial pull force; but, under the lateral tension, the secondary structures at both terminals of FLNa17 would unfold to protect the interface of the GPIbα-CT/FLNa17 complex from mechanical damage. In the range of 0~40 pN, the increase of pull force promoted outward-rotation of the nitrogen atom of the 563 rd phenylalanine (PHE 563-N) at GPIbα-CT and the dissociation of the complex. This study for the first time revealed that the extracellular ligand-transmitted axial force could more effectively relieve the inhibition of FLNa17 on the downstream signal of GPIbα than pure mechanical tension at the atomic level, and would be useful for further understanding the platelet intracellular force-regulated signal pathway.
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Affiliation(s)
- 人才 陶
- 华南理工大学 生物科学与工程学院(广州 510006)School of Bioscience & Bioengineering, South China University of Technology, Guangzhou 510006, P. R. China
| | - 旭斌 谢
- 华南理工大学 生物科学与工程学院(广州 510006)School of Bioscience & Bioengineering, South China University of Technology, Guangzhou 510006, P. R. China
| | - 建华 吴
- 华南理工大学 生物科学与工程学院(广州 510006)School of Bioscience & Bioengineering, South China University of Technology, Guangzhou 510006, P. R. China
| | - 颖 方
- 华南理工大学 生物科学与工程学院(广州 510006)School of Bioscience & Bioengineering, South China University of Technology, Guangzhou 510006, P. R. China
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5
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Beck S, Öftering P, Li R, Hemmen K, Nagy M, Wang Y, Zarpellon A, Schuhmann MK, Stoll G, Ruggeri ZM, Heinze KG, Heemskerk JW, Ruf W, Stegner D, Nieswandt B. Platelet glycoprotein V spatio-temporally controls fibrin formation. NATURE CARDIOVASCULAR RESEARCH 2023; 2:368-382. [PMID: 37206993 PMCID: PMC10195106 DOI: 10.1038/s44161-023-00254-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 02/15/2023] [Indexed: 05/21/2023]
Abstract
The activation of platelets and coagulation at vascular injury sites is crucial for haemostasis but can promote thrombosis and inflammation in vascular pathologies. Here, we delineate an unexpected spatio-temporal control mechanism of thrombin activity that is platelet orchestrated and locally limits excessive fibrin formation after initial haemostatic platelet deposition. During platelet activation, the abundant platelet glycoprotein (GP) V is cleaved by thrombin. We demonstrate with genetic and pharmacological approaches that thrombin-mediated shedding of GPV does not primarily regulate platelet activation in thrombus formation, but rather has a distinct function after platelet deposition and specifically limits thrombin-dependent generation of fibrin, a crucial mediator of vascular thrombo-inflammation. Genetic or pharmacologic defects in haemostatic platelet function are unexpectedly attenuated by specific blockade of GPV shedding, indicating that the spatio-temporal control of thrombin-dependent fibrin generation also represents a potential therapeutic target to improve haemostasis.
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Affiliation(s)
- Sarah Beck
- Julius-Maximilians-Universität Würzburg, Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
- University Hospital Würzburg, Institute of Experimental Biomedicine, Würzburg, Germany
| | - Patricia Öftering
- Julius-Maximilians-Universität Würzburg, Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
- University Hospital Würzburg, Institute of Experimental Biomedicine, Würzburg, Germany
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine; Atlanta, USA
| | - Katherina Hemmen
- Julius-Maximilians-Universität Würzburg, Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
| | - Magdolna Nagy
- Department of Biochemistry, CARIM, Maastricht University; Maastricht, The Netherlands
| | - Yingchun Wang
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine; Atlanta, USA
| | | | | | - Guido Stoll
- University Hospital Würzburg, Department of Neurology, Würzburg, Germany
| | | | - Katrin G. Heinze
- Julius-Maximilians-Universität Würzburg, Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
| | - Johan W.M. Heemskerk
- Department of Biochemistry, CARIM, Maastricht University; Maastricht, The Netherlands
| | - Wolfram Ruf
- Center for Thrombosis and Hemostasis (CTH), Johannes Gutenberg University Medical Center Mainz; Mainz, Germany
- Department of Immunology and Microbiology, Scripps Research; La Jolla, CA, USA
| | - David Stegner
- Julius-Maximilians-Universität Würzburg, Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
- University Hospital Würzburg, Institute of Experimental Biomedicine, Würzburg, Germany
| | - Bernhard Nieswandt
- Julius-Maximilians-Universität Würzburg, Rudolf Virchow Center for Integrative and Translational Bioimaging, Würzburg, Germany
- University Hospital Würzburg, Institute of Experimental Biomedicine, Würzburg, Germany
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6
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Bendas G, Schlesinger M. The GPIb-IX complex on platelets: insight into its novel physiological functions affecting immune surveillance, hepatic thrombopoietin generation, platelet clearance and its relevance for cancer development and metastasis. Exp Hematol Oncol 2022; 11:19. [PMID: 35366951 PMCID: PMC8976409 DOI: 10.1186/s40164-022-00273-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/19/2022] [Indexed: 12/13/2022] Open
Abstract
The glycoprotein (GP) Ib-IX complex is a platelet receptor that mediates the initial interaction with subendothelial von Willebrand factor (VWF) causing platelet arrest at sites of vascular injury even under conditions of high shear. GPIb-IX dysfunction or deficiency is the reason for the rare but severe Bernard-Soulier syndrome (BSS), a congenital bleeding disorder. Although knowledge on GPIb-IX structure, its basic functions, ligands, and intracellular signaling cascades have been well established, several advances in GPIb-IX biology have been made in the recent years. Thus, two mechanosensitive domains and a trigger sequence in GPIb were characterized and its role as a thrombin receptor was deciphered. Furthermore, it became clear that GPIb-IX is involved in the regulation of platelet production, clearance and thrombopoietin secretion. GPIb is deemed to contribute to liver cancer development and metastasis. This review recapitulates these novel findings highlighting GPIb-IX in its multiple functions as a key for immune regulation, host defense, and liver cancer development.
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Affiliation(s)
- Gerd Bendas
- Department of Pharmacy, Rheinische Friedrich-Wilhelms-University Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Martin Schlesinger
- Department of Pharmacy, Rheinische Friedrich-Wilhelms-University Bonn, An der Immenburg 4, 53121, Bonn, Germany. .,Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany.
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7
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Kimmerlin Q, Moog S, Ravanat C, Strassel C, Lanza F. Glycoprotein V : the unsolved GPV puzzle. Platelets 2022; 33:833-840. [PMID: 34994277 DOI: 10.1080/09537104.2021.2022114] [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: 10/19/2022]
Abstract
Glycoprotein V (GPV) is a highly expressed 82 KDa platelet surface transmembrane protein which is loosely attached to the GPIb-IX complex. Despite remaining questions concerning its function, GPV presents several unique features which have repercussions in hematology, atherothrombosis, immunology and transfusion. GPV is specifically expressed in platelets and megakaryocytes and is an ideal marker and reporter gene for the late stages of megakaryopoiesis. The ectodomain of GPV can be released by a number of proteases, namely thrombin, elastase and ADAM10 and 17. Although it was originally proposed as a thrombin receptor, this hypothesis was abandoned since thrombin activation was preserved after blockade of GPV cleavage and in Gp5 knockout mice. The combined potential of GPV to reflect the direct action of thrombin, platelet exposure to strong agonists and inflammatory conditions has led one to evaluate its utility as a marker in the context of atherothrombosis. Increased plasma levels of soluble GPV have notably been recorded in myocardial infarction, stroke and venous thromboembolism. It is also highly valued in transfusion to monitor platelet storage lesions. GPV presents several polymorphisms, which are a possible source of alloantibodies, while autoantibodies have been frequently detected in immune thrombocytopenia. The real biological function of this glycoprotein nevertheless remains an enigma, despite the respectively decreased and increased responses to low concentrations of collagen and thrombin observed in Gp5 knockout mice. Current studies are exploring its role in modulating general or VWF-induced platelet signaling, which could bear relevance in thrombosis and platelet clearance.
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Affiliation(s)
- Quentin Kimmerlin
- Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Sylvie Moog
- Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Catherine Ravanat
- Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Catherine Strassel
- Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - François Lanza
- Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
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8
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Abstract
Platelet adhesion to the site of vascular damage is a critical early step in hemostasis. The platelet glycoprotein (GP) Ib-IX-V plays a key role in this step via its interaction with immobilized von Willebrand Factor (VWF). In addition to its well-known role in adhesion, GPIb-IX-V is critical for platelets' survival in circulation and plays an important role in the regulation of platelet clearance. Several mechanisms of platelet clearance work in concert to maintain a normal platelet count and ensure that circulating platelets are functionally viable via removal of senescent or activated platelets. Furthermore, dysregulation of platelet clearance underlies several bleeding disorders. GPIb-IX-V is central to many physiological mechanisms of platelet clearance including clearance via glycan receptors, clearance of VWF-platelet complexes, and fast clearance of transfused platelets. GPIb-IX-V dependent clearance also underlies thrombocytopenia in several bleeding disorders, including von Willebrand disease (VWD) and immune thrombocytopenia. This review will cover physiological and pathological mechanisms of platelet clearance, focusing on the role of GPIb-IX-V.
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Affiliation(s)
- M Edward Quach
- Stem Cell Program, Boston Children's Hospital, Boston, MA, USA.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
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9
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Quach ME, Li R. Structure-function of platelet glycoprotein Ib-IX. J Thromb Haemost 2020; 18:3131-3141. [PMID: 32735697 PMCID: PMC7854888 DOI: 10.1111/jth.15035] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 12/20/2022]
Abstract
The glycoprotein (GP)Ib-IX receptor complex plays a critical role in platelet physiology and pathology. Its interaction with von Willebrand factor (VWF) on the subendothelial matrix instigates platelet arrest at the site of vascular injury and is vital to primary hemostasis. Its reception to other ligands and counter-receptors in the bloodstream also contribute to various processes of platelet biology that are still being discovered. While its basic composition and its link to congenital bleeding disorders were well documented and firmly established more than 25 years ago, recent years have witnessed critical advances in the organization, dynamics, activation, regulation, and functions of the GPIb-IX complex. This review summarizes important findings and identifies questions that remain about this unique platelet mechanoreceptor complex.
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Affiliation(s)
- M Edward Quach
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, USA
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, USA
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10
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Tao Y, Gan C, Zhang X, Liu L, Zakas PM, Doering CB, Mo X, Li R. Unaccompanied mechanosensory domain mediates low expression of glycoprotein Ibα: implications for Bernard-Soulier syndrome. J Thromb Haemost 2020; 18:510-517. [PMID: 31749281 PMCID: PMC7592420 DOI: 10.1111/jth.14684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/18/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND Disruption of protein folding or inter-subunit interactions in the platelet glycoprotein (GP)Ib-IX complex leads to its abnormally low expression in the plasma membrane, the hallmark of Bernard-Soulier syndrome (BSS). OBJECTIVE To discover the molecular mechanism by which GPIbα in the absence of GPIbβ and GPIX subunits is targeted for rapid degradation. METHOD The expression of GPIbα mutants with deletion or replacement of various domains were measured in transiently transfected Chinese hamster ovary cells. RESULTS We report evidence to suggest that induction of the unfolded protein response by the unaccompanied mechanosensory domain (MSD) is a major factor for intracellular degradation and low expression of GPIbα. Removal of the MSD produced the first GPIbα variant that, even in the absence of GPIbβ and GPIX, expressed at a level comparable to that of wild-type GPIbα in the GPIb-IX complex, while retaining its native ligand-binding activity. CONCLUSION Our finding has important implications on the molecular pathogenesis of BSS and the function of the GPIb-IX complex.
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Affiliation(s)
- Yue Tao
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Chi Gan
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Xiaoqin Zhang
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Lanbo Liu
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Philip M. Zakas
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Christopher B. Doering
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Xi Mo
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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11
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Chen Q, Yang H, Li Y, Wang X, Wei L, Du Y. Effects of Yak skin gelatin on platelet activation. Food Funct 2019; 10:3379-3385. [PMID: 31107473 DOI: 10.1039/c8fo02513d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Studies have shown that gelatin is not only a good hemostatic material, but also a food additive with potentially broad use. Yak skin gelatin is a new gelatin resource, but its oral coagulant effects have not been studied. Given the central role of platelets in hemostasis, in this study we examined the pharmacodynamical differences between different molecular Yak skin gelatins on platelet activation. The hemostatic effects of Yak skin gelatins with different molecular weight distributions were evaluated for bleeding time (BT), clotting time (CT), and platelet activity by measuring the contents of P-selectin, platelet membrane glycoprotein Ia/IIa (GP Ia/IIa), platelet membrane glycoprotein IIb/IIIa (GP IIb/IIIa), and platelet membrane glycoprotein IV (GP IV). Intragastric administration of Yak skin gelatin resulted in a significant reduction in CT and BT, and an increase in the contents of P-selectin, GP Ia/IIa, GP IIb/IIIa, and GP IV in all groups in comparison with the control group. The strongest activation of platelets by Yak skin gelatin was observed with size between 0.1 μm and 0.22 μm, and activation may have been in response to improving GP IIb/IIIa and GP IV levels. When measuring the levels of an established indicator of platelet activation, platelet activation-dependent granule membrane protein (CD62P), its promotion was observed for all molecular weight ranges of Yak skin gelatins. In brief, Yak skin gelatin has hemostatic effects, and Yak skin gelatin fractions between 0.1 μm and 0.22 μm are the primary effectors of hemostasis via promoting platelet membrane glycoprotein activities and strengthening platelet function.
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Affiliation(s)
- Qi Chen
- Qinghai Key Laboratory of Tibetan Medicine Pharmacology and Safety Evaluation, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Chinese Academy of Sciences, 810008 Xining, China.
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Tseytin I, Mitrovic B, David N, Langenfeld K, Zarivach R, Diepold A, Sal-Man N. The Role of the Small Export Apparatus Protein, SctS, in the Activity of the Type III Secretion System. Front Microbiol 2019; 10:2551. [PMID: 31798543 PMCID: PMC6863770 DOI: 10.3389/fmicb.2019.02551] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/22/2019] [Indexed: 12/15/2022] Open
Abstract
Many gram-negative pathogens utilize a protein complex, termed the type III secretion system (T3SS), to inject virulence factors from their cytoplasm directly into the host cell. An export apparatus that is formed by five putative integral membrane proteins (SctR/S/T/U/V), resides at the center of the T3SS complex. In this study, we characterized the smallest export apparatus protein, SctS, which contains two putative transmembrane domains (PTMD) that dynamically extract from the inner membrane and adopt a helix-turn-helix structure upon assembly of the T3SS. Replacement of each SctS PTMD with an alternative hydrophobic sequence resulted in abolishment of the T3SS activity, yet SctS self- and hetero-interactions as well as the overall assembly of the T3SS complex were unaffected. Our findings suggest that SctS PTMDs are not crucial for the interactions or the assembly of the T3SS base complex but rather that they are involved in adjusting the orientation of the export apparatus relative to additional T3SS sub-structures, such as the cytoplasmic- and the inner-membrane rings. This ensures the fittings between the dynamic and static components of the T3SS and supports the functionality of the T3SS complex.
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Affiliation(s)
- Irit Tseytin
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Bosko Mitrovic
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Nofar David
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Katja Langenfeld
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Raz Zarivach
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
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[Platelet GPⅠb-Ⅸ-Ⅴ receptor-mediated mechanism and its application in thrombotic diseases]. ZHONGHUA XUE YE XUE ZA ZHI = ZHONGHUA XUEYEXUE ZAZHI 2019; 40:532-536. [PMID: 31340631 PMCID: PMC7342399 DOI: 10.3760/cma.j.issn.0253-2727.2019.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Chen J, Schroeder JA, Luo X, Montgomery RR, Shi Q. The impact of GPIbα on platelet-targeted FVIII gene therapy in hemophilia A mice with pre-existing anti-FVIII immunity. J Thromb Haemost 2019; 17:449-459. [PMID: 30609275 PMCID: PMC6397061 DOI: 10.1111/jth.14379] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Indexed: 01/13/2023]
Abstract
Essentials Platelet-specific FVIII gene therapy is effective in hemophilia A mice even with inhibitors. The impact of platelet adherence via VWF/GPIbα binding on platelet gene therapy was investigated. GPIbα does not significantly affect platelet gene therapy of hemophilia A with inhibitors. Platelet gene therapy induces immune tolerance in hemophilia A mice with pre-existing immunity. SUMMARY: Background We have previously demonstrated that von Willebrand factor (VWF) is essential in platelet-specific FVIII (2bF8) gene therapy of hemophilia A (HA) with inhibitory antibodies (inhibitors). At the site of injury, platelet adherence is initiated by VWF binding to the platelet GPIb complex. Objective To investigate the impact of GPIbα on platelet gene therapy of HA with inhibitors. Methods Platelet-FVIII expression was introduced by 2bF8 lentivirus (2bF8LV) transduction of hematopoietic stem cells (HSCs) from GPIbαnull (Ibnull ) mice or rhF8-primed FVIIInull (F8null ) mice followed by transplantation into lethally irradiated rhF8-primed F8null recipients. Animals were analyzed by flow cytometry, FVIII assays and the tail bleeding test. Results After transplantation, 99% of platelets were derived from donors. The macrothrombocytopenia phenotype was maintained in F8null mice that received 2bF8LV-transduced Ibnull HSCs (2bF8-Ibnull /F8null ). The platelet-FVIII expression level in 2bF8-Ibnull /F8null recipients was similar to that obtained from F8null mice that received 2bF8LV-transduced F8null HSCs (2bF8-F8null /F8null ). The tail bleeding test showed that the remaining hemoglobin level in the 2bF8-Ibnull /F8null group was significantly higher than in the F8null control group, but there was no significant difference between the 2bF8-Ibnull /F8null and 2bF8-F8null /F8null groups. The half-life of inhibitor disappearance time was comparable between the 2bF8-Ibnull /F8null and 2bF8-F8null /F8null groups. The rhF8 re-challenge did not elicit a memory immune response once inhibitor titers dropped to undetectable levels after 2bF8 gene therapy. Conclusion GPIbα does not significantly impact platelet gene therapy of HA with inhibitors. 2bF8 gene therapy restores hemostasis and promotes immune tolerance in HA mice with pre-existing immunity.
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Affiliation(s)
- Juan Chen
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
| | - Jocelyn A. Schroeder
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Children’s Research Institute, Children’s Hospital of Wisconsin, Milwaukee, Wisconsin, USA
- MACC Fund Research Center, Milwaukee, WI, USA
| | - Xiaofeng Luo
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
| | - Robert R. Montgomery
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Children’s Research Institute, Children’s Hospital of Wisconsin, Milwaukee, Wisconsin, USA
- MACC Fund Research Center, Milwaukee, WI, USA
| | - Qizhen Shi
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Children’s Research Institute, Children’s Hospital of Wisconsin, Milwaukee, Wisconsin, USA
- MACC Fund Research Center, Milwaukee, WI, USA
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15
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The Glycoprotein Ib-IX-V Complex. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00010-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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The Third Transmembrane Domain of EscR Is Critical for Function of the Enteropathogenic Escherichia coli Type III Secretion System. mSphere 2018; 3:3/4/e00162-18. [PMID: 30045964 PMCID: PMC6060343 DOI: 10.1128/msphere.00162-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Many Gram-negative bacterial pathogens that cause life-threatening diseases employ a type III secretion system (T3SS) for their virulence. The T3SS comprises several proteins that assemble into a syringe-like structure dedicated to the injection of bacterial virulence factors into the host cells. Although many T3SS proteins are transmembrane proteins, our knowledge of these proteins is limited mostly to their soluble domains. In this study, we found that the third transmembrane domain (TMD) of EscR, a central protein of the T3SS in enteropathogenic E. coli, contributes to protein self-oligomerization. Moreover, we demonstrated that a single aspartic acid residue, located at the core of this TMD, is critical for the activity of the full-length protein and the function of the entire T3SS, possibly due to its involvement in mediating TMD-TMD interactions. Our findings should encourage the mapping of the entire interactome of the T3SS components, including interactions mediated through their TMDs. Many Gram-negative bacterial pathogens utilize a specialized protein delivery system, called the type III secretion system (T3SS), to translocate effector proteins into the host cells. The translocated effectors are crucial for bacterial infection and survival. The base of the T3SS transverses both bacterial membranes and contains an export apparatus that comprises five membrane proteins. Here, we study the export apparatus of enteropathogenic Escherichia coli (EPEC) and characterize its central component, called the EscR protein. We found that the third transmembrane domain (TMD) of EscR mediates strong self-oligomerization in an isolated genetic reporter system. Replacing this TMD sequence with an alternative hydrophobic sequence within the full-length protein resulted in a complete loss of function of the T3SS, further suggesting that the EscR TMD3 sequence has another functional role in addition to its role as a membrane anchor. Moreover, we found that an aspartic acid residue, located at the core of EscR TMD3, is important for the oligomerization propensity of TMD3 and that a point mutation of this residue within the full-length protein abolishes the T3SS activity and the ability of the bacteria to translocate effectors into host cells. IMPORTANCE Many Gram-negative bacterial pathogens that cause life-threatening diseases employ a type III secretion system (T3SS) for their virulence. The T3SS comprises several proteins that assemble into a syringe-like structure dedicated to the injection of bacterial virulence factors into the host cells. Although many T3SS proteins are transmembrane proteins, our knowledge of these proteins is limited mostly to their soluble domains. In this study, we found that the third transmembrane domain (TMD) of EscR, a central protein of the T3SS in enteropathogenic E. coli, contributes to protein self-oligomerization. Moreover, we demonstrated that a single aspartic acid residue, located at the core of this TMD, is critical for the activity of the full-length protein and the function of the entire T3SS, possibly due to its involvement in mediating TMD-TMD interactions. Our findings should encourage the mapping of the entire interactome of the T3SS components, including interactions mediated through their TMDs.
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17
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Platelet clearance via shear-induced unfolding of a membrane mechanoreceptor. Nat Commun 2016; 7:12863. [PMID: 27670775 PMCID: PMC5052631 DOI: 10.1038/ncomms12863] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 08/10/2016] [Indexed: 12/26/2022] Open
Abstract
Mechanisms by which blood cells sense shear stress are poorly characterized. In platelets, glycoprotein (GP)Ib–IX receptor complex has been long suggested to be a shear sensor and receptor. Recently, a relatively unstable and mechanosensitive domain in the GPIbα subunit of GPIb–IX was identified. Here we show that binding of its ligand, von Willebrand factor, under physiological shear stress induces unfolding of this mechanosensory domain (MSD) on the platelet surface. The unfolded MSD, particularly the juxtamembrane ‘Trigger' sequence therein, leads to intracellular signalling and rapid platelet clearance. These results illustrate the initial molecular event underlying platelet shear sensing and provide a mechanism linking GPIb–IX to platelet clearance. Our results have implications on the mechanism of platelet activation, and on the pathophysiology of von Willebrand disease and related thrombocytopenic disorders. The mechanosensation via receptor unfolding may be applicable for many other cell adhesion receptors. The platelets detect and respond to shear stress generated by blood flow. Here the authors show that the binding of the soluble von Willebrand factor to its receptor GPIba under physiological shear stress induces receptor's domain unfolding on the platelet and signalling into the platelet, leading to platelets clearance.
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18
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Strassel C, Bull A, Moog S, Receveur N, Mallo L, Mangin P, Eckly A, Freund M, Dubart-Kupperschmitt A, Gachet C, Lanza F. Lentiviral gene rescue of a Bernard-Soulier mouse model to study platelet glycoprotein Ibβ function. J Thromb Haemost 2016; 14:1470-9. [PMID: 27148783 DOI: 10.1111/jth.13355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 03/29/2016] [Indexed: 12/01/2022]
Abstract
UNLABELLED Essentials A signaling role of glycoprotein (GP)Ibβ is postulated but not formally demonstrated in platelets. Lentiviral-mediated rescue in knock-out mice can be used to evaluate GPIbβ function in vivo. Transduction of the native subunit corrected the main defects associated with GPIb-IX deficiency Deletion of intracellular 159-170 segment increased thrombosis, 150-160 removal increased bleeding. SUMMARY Background The platelet glycoprotein (GP)Ib-V-IX complex is required for normal hemostasis and megakaryopoiesis. A role in GPIb-dependent responses has been ascribed to the less well characterized GPIbβ subunit using a specific antibody and GPIb-IX transfected cells. Objectives Our aim was to evaluate, in vivo, the role of the GPIbβ in hemostasis and thrombosis. Methods GPIbβ(null) Sca-1(+) progenitors transduced with viral particles harboring hGPIbβ were transplanted into lethally irradiated GPIbβ(-/-) recipient mice. Results hGPIbβ transplanted into the bone marrow of GPIbβ(null) mice rescued GPIb-IX expression in 97% of circulating platelets. These platelets efficiently bound von Willebrand factor (VWF) and extended filopodia on a VWF matrix, demonstrating the restoration of GPIb-dependent adhesive and signaling properties. These mice exhibited less severe macrothrombocytopenia and had normal tail bleeding times as compared with GPIbβ(null) mice. This strategy was employed to manipulate and evaluate the role of the GPIbβ intracellular domain. Removal of the membrane proximal segment (Δ(150-160) ) decreased GPIb-IX expression by 43%, confirming its involvement in receptor assembly and biosynthesis, and resulted in increased bleeding times and decreased thrombosis in a mechanical injury model in the aorta. On the other hand, deletion of the C-flanking 159-170 segment allowed normal GPIb-IX expression, VWF-dependent responses and bleeding times, but resulted in enhanced arterial thrombosis. Conclusion This pointed to a repressor role of GPIbβ in thrombus formation in vivo that was not predicted in studies of heterologous cells. These results highlight the utility of this lentiviral strategy for the structure-function evaluation of GPIb-IX in platelets.
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Affiliation(s)
- C Strassel
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - A Bull
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - S Moog
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - N Receveur
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - L Mallo
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - P Mangin
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - A Eckly
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - M Freund
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - A Dubart-Kupperschmitt
- INSERM U1193, Hôpital Paul Brousse, Villejuif, France
- UMR_S1193, Université Paris-Sud, Hôpital Paul Brousse, Villejuif, France
- Département hospitalo-universitaire Hepatinov, Hôpital Paul Brousse, Villejuif, France
| | - C Gachet
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - F Lanza
- UMR_S949 INSERM, Strasbourg, France
- Etablissement Français du Sang (EFS)-Alsace, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France
- Université de Strasbourg, Strasbourg, France
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Shlebak A, Poles A, Manning R, Almuhareb S, De La Funte J, Mitchell M, Lucas G. A Novel Homozygous c.800C>G Substitution in GP1BA Exon 2 in a Kuwaiti Family with Bernard-Soulier Syndrome. Acta Haematol 2015; 134:193-8. [PMID: 26044173 DOI: 10.1159/000381328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 03/02/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND Bernard-Soulier syndrome (BSS) is a congenital bleeding disorder characterised by thrombocytopenia, giant platelets and decreased platelet adhesion resulting from genetic alterations of the glycoprotein (GP) Ib/IX/V complex. OBJECTIVES Three sisters with a lifelong bleeding history and a provisional diagnosis of BSS were referred for further characterisation of their bleeding diathesis. The siblings' symptoms varied in severity from skin and gum bleeding to menorrhagia associated with iron-deficiency anaemia requiring regular transfusion of red cells and platelets. The parents were consanguineous but did not demonstrate any bleeding disorder. METHODS The family were investigated using standard haematological techniques, platelet aggregometry, platelet membrane GP analysis and DNA sequencing of the genes encoding the GPIb/IX complex. RESULTS All 3 sisters had thrombocytopenia and giant platelets. Platelet aggregation and flow cytometry studies confirmed the lack of aggregation with ristocetin and a markedly reduced GPIb/IX surface expression. Molecular analysis demonstrated a novel homozygous c.800C>G substitution in GP1BA exon 2 leading to a serine 267 Ter stop codon in all 3 siblings. CONCLUSIONS A novel, nonsense mutation was identified as the cause of the bleeding disorder in this family. This is the first reported BSS mutation identified in a family from Kuwait.
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Affiliation(s)
- Abdul Shlebak
- Haemostasis and Thrombosis Unit, Imperial College Healthcare, St. Thomas' Hospital, London, UK
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Zhou L, Yang W, Li R. Analysis of inter-subunit contacts reveals the structural malleability of extracellular domains in platelet glycoprotein Ib-IX complex. J Thromb Haemost 2014; 12:82-9. [PMID: 24406065 PMCID: PMC4137403 DOI: 10.1111/jth.12437] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND The glycoprotein (GP)Ib-IX complex is critical to hemostasis and thrombosis. Its proper assembly is closely correlated with its surface expression level and requires cooperative interactions among extracellular and transmembrane domains of Ibα, Ibβ and IX subunits. Two interfaces have been previously identified between the extracellular domains of Ibβ and IX. OBJECTIVE To understand how extracellular domains interact in GPIb-IX. METHODS The Ibβ extracellular domain (IbβE ) or the IX counterpart (IXE ) in GPIb-IX was replaced with a well-folded IbβE /IXE chimera called IbβEabc , and the effect of domain replacement on assembly and expression of the receptor complex in transiently transfected Chinese hamster ovary cells was analyzed. RESULTS Replacing IXE with IbβEabc in GPIb-IX retained interface 1 but not interface 2 between the extracellular domains. While this domain replacement preserved complex integrity, the expression levels of Ibβ and Ibα were significantly reduced. Additional domain replacement with IbβEabc or IbβE in GPIb-IX produced the complex at disparate expression levels that cannot be simply explained by two separate interfaces. In particular, when IbβE in GPIb-IX was replaced by IbβEabc , Ibα and IX were expressed at approximately 70% of the wild-type level. Their levels were not reduced when IXE was changed further to IbβE . CONCLUSIONS Our results demonstrate the importance of the association between Ibβ and IX extracellular domains for complex assembly and efficient expression, and provide evidence for the structural malleability of these domains that may accommodate and propagate conformational changes therein.
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Affiliation(s)
- L Zhou
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University School of Medicine, Atlanta, GA, USA
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Brandt KJ, Kruithof EKO, de Moerloose P. Receptors involved in cell activation by antiphospholipid antibodies. Thromb Res 2013; 132:408-13. [PMID: 24054056 DOI: 10.1016/j.thromres.2013.08.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 08/16/2013] [Accepted: 08/18/2013] [Indexed: 02/08/2023]
Abstract
The antiphospholipid syndrome (APS) is an autoimmune disease associated with arterial or venous thrombosis and/or recurrent fetal loss and is caused by pathogenic antiphospholipid antibodies (aPLA). The plasma protein β2-glycoprotein 1 (β2GP1) has been identified as a major target of aPLA associated with APS. Cell activation by aPLA appears to be a major pathogenic cause in the pathogenesis of APS. Receptors, co-receptors and accessory molecules are known to assist the pathogenic effects of aPLA. Members of the TLR family and the platelet receptor apolipoprotein E receptor 2' (apoER2'), a receptor belonging to the low-density lipoprotein receptor (LDL-R) family, as well as GPIbα, were identified as putative candidates for aPLA recognition. CD14, a co-receptor for TLR2 and TLR4, and annexin A2, a ubiquitous Ca2+ -binding protein that is essential for actin-dependent vesicle transport, could serve as important accessory molecules in mediating the pathogenic effects of aPLA. Finally, complement activation has been reported in association with the pathogenicity of APS. The relative contribution of these different mechanisms in the pathogenesis of APS is controversial. Here, we review the various in vivo and in vitro models that have been used to investigate the pathogenic mechanisms of aPLA in APS.
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Affiliation(s)
- Karim J Brandt
- Division of Angiology and Hemostasis, University Hospital of Geneva and Faculty of Medicine, Geneva, Switzerland.
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Maurer E, Tang C, Schaff M, Bourdon C, Receveur N, Ravanat C, Eckly A, Hechler B, Gachet C, Lanza F, Mangin PH. Targeting platelet GPIbβ reduces platelet adhesion, GPIb signaling and thrombin generation and prevents arterial thrombosis. Arterioscler Thromb Vasc Biol 2013; 33:1221-9. [PMID: 23559635 DOI: 10.1161/atvbaha.112.301013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The glycoprotein (GP) Ib-V-IX complex regulates the adhesion, activation, and procoagulant activity of platelets. We previously reported that RAM.1, a rat monoclonal antibody directed against the extracellular domain of mouse GPIbβ, diminished adhesion of platelets and chinese hamster ovary cells transfected with the human GPIb-IX complex to von Willebrand factor under flow conditions. Here, we further evaluated the functional importance of GPIbβ by studying the impact of RAM.1 on GPIb-mediated platelet responses and in vitro and in vivo thrombus formation. APPROACH AND RESULTS We show that RAM.1 dramatically reduced GPIb-mediated filopodia extension of chinese hamster ovary GPIb-IX cells after adhesion to von Willebrand factor. RAM.1 also reduced filopodia extension and GPIb-mediated Ca(2+) signaling after adhesion of mouse platelets to von Willebrand factor. RAM.1 inhibited thrombin generation in platelet-rich plasma without impairing phosphatidylserine exposure. In addition, RAM.1 reduced thrombus formation after perfusion of mouse whole blood over collagen in a shear-dependent manner. This effect was confirmed in vivo, because injection of F(ab)'2 fragments of RAM.1 diminished thrombus formation induced by laser beam injury of mesenteric arterioles and forceps injury of the abdominal aorta. In contrast, RAM.1 F(ab)'2 did not prolong the tail-bleeding time or increase the volume of blood lost. CONCLUSIONS These findings are the first evidence that targeting a subunit other than GPIbα can lead to an antithrombotic effect via the GPIb-V-IX complex. This could represent an alternative way to reduce thrombus formation with a minor impact on hemostasis.
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Affiliation(s)
- Eric Maurer
- Inserm UMR-S949, Université Université de Strasbourg, Etablissement Français du Sang-Alsace (EFS-Alsace), Strasbourg, France
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Li R, Emsley J. The organizing principle of the platelet glycoprotein Ib-IX-V complex. J Thromb Haemost 2013; 11:605-14. [PMID: 23336709 PMCID: PMC3696474 DOI: 10.1111/jth.12144] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 01/17/2013] [Indexed: 11/28/2022]
Abstract
The glycoprotein (GP)Ib-IX-V complex is the platelet receptor for von Willebrand factor and many other molecules that are critically involved in hemostasis and thrombosis. The lack of functional GPIb-IX-V complexes on the platelet surface is the cause of Bernard-Soulier syndrome, a rare hereditary bleeding disorder that is also associated with macrothrombocytopenia. GPIb-IX-V contains GPIbα, GPIbβ, GPIX and GPV subunits, all of which are type I transmembrane proteins containing leucine-rich repeat domains. Although all of the subunits were identified decades ago, not until recently did the mechanism of complex assembly begin to emerge from a systematic characterization of inter-subunit interactions. This review summarizes the forces driving the assembly of GPIb-IX-V, discusses their implications for the pathogenesis of Bernard-Soulier syndrome, and identifies questions that remain about the structure and organization of GPIb-IX-V.
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Affiliation(s)
- R Li
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University School of Medicine, Atlanta, GA30322, USA.
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