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Alenazy FO, Harbi MH, Kavanagh DP, Price J, Brady P, Hargreaves O, Harrison P, Slater A, Tiwari A, Nicolson PLR, Connolly DL, Kirchhof P, Kalia N, Jandrot-Perrus M, Mangin PH, Watson SP, Thomas MR. Amplified inhibition of atherosclerotic plaque-induced platelet activation by glenzocimab with dual antiplatelet therapy. J Thromb Haemost 2023; 21:3236-3251. [PMID: 37541591 DOI: 10.1016/j.jtha.2023.07.018] [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: 01/22/2023] [Revised: 06/23/2023] [Accepted: 07/16/2023] [Indexed: 08/06/2023]
Abstract
BACKGROUND Aspirin and platelet P2Y12 inhibitors, such as ticagrelor, suboptimally inhibit microvascular thrombosis during ST-elevation myocardial infarction. Glycoprotein (GP) IIb/IIIa inhibitors may further inhibit this but cause excessive bleeding. OBJECTIVES We investigated whether combination of glenzocimab, a GPVI inhibitor, with aspirin and ticagrelor provides additional antithrombotic effects, as GPVI has a critical role in atherothrombosis but minimal involvement in hemostasis. METHODS We investigated the effects of glenzocimab (monoclonal antibody Fab fragment) using blood from healthy donors and patients with acute coronary syndrome treated with aspirin and ticagrelor. Platelets were stimulated with multiple agonists, including atherosclerotic plaque, from patients undergoing carotid endarterectomy. RESULTS Aspirin and ticagrelor partially inhibited atherosclerotic plaque-induced platelet aggregation by 48% compared with control (34 ± 3 vs 65 ± 4 U; P < .001). Plaque-induced platelet aggregation, adhesion, secretion, and activation were critically dependent on GPVI activation. Glenzocimab alone reduced plaque-induced aggregation by 75% compared with control (16 ± 4 vs 65 ± 4 U; P < .001) and by >95% when combined with aspirin and ticagrelor (3 ± 1 vs 65 ± 4 U; P < .001). Glenzocimab reduced platelet aggregation, adhesion, and thrombin generation when added to blood of aspirin- and ticagrelor-treated patients with acute coronary syndrome. Glenzocimab shared several antithrombotic effects with the GPIIb/IIIa inhibitor eptifibatide with less effect on general hemostasis assessed by rotational thromboelastometry. In a murine intravital model of ST-elevation myocardial infarction, genetic depletion of GPVI reduced microvascular thrombosis. CONCLUSION Addition of glenzocimab to aspirin and ticagrelor enhances platelet inhibition via multiple mechanisms of atherothrombosis. Compared with a GPIIb/IIIa inhibitor, glenzocimab shares multiple antithrombotic effects, with less inhibition of mechanisms involved in general hemostasis.
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Affiliation(s)
- Fawaz O Alenazy
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka, Saudi Arabia
| | - Maan H Harbi
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Pharmacology and Toxicology Department, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Dean P Kavanagh
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Joshua Price
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Paul Brady
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiology, Sandwell and West Birmingham Hospitals National Health Service (NHS) Trust, Birmingham, United Kingdom
| | - Oscar Hargreaves
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Paul Harrison
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, United Kingdom
| | - Alexandre Slater
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Alok Tiwari
- Department of Vascular Surgery, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Phillip L R Nicolson
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Derek L Connolly
- Department of Cardiology, Sandwell and West Birmingham Hospitals National Health Service (NHS) Trust, Birmingham, United Kingdom
| | - Paulus Kirchhof
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiology, University Heart and Vascular Center (UKE) Hamburg, Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Germany
| | - Neena Kalia
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | | | - Pierre H Mangin
- UMR_S1255, INSERM, Etablissement Francais du Sang-Alsace, Strasbourg, France
| | - Steve P Watson
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), The Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Mark R Thomas
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom; Department of Cardiology, Sandwell and West Birmingham Hospitals National Health Service (NHS) Trust, Birmingham, United Kingdom; Department of Cardiology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.
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2
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Jooss NJ, Henskens YMC, Watson SP, Farndale RW, Gawaz MP, Jandrot-Perrus M, Poulter NS, Heemskerk JWM. Pharmacological Inhibition of Glycoprotein VI- and Integrin α2β1-Induced Thrombus Formation Modulated by the Collagen Type. Thromb Haemost 2023; 123:597-612. [PMID: 36807826 DOI: 10.1055/s-0043-1761463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND In secondary cardiovascular disease prevention, treatments blocking platelet-derived secondary mediators pose a risk of bleeding. Pharmacological interference of the interaction of platelets with exposed vascular collagens is an attractive alternative, with clinical trials ongoing. Antagonists of the collagen receptors, glycoprotein VI (GPVI), and integrin α2β1, include recombinant GPVI-Fc dimer construct Revacept, 9O12 mAb based on the GPVI-blocking reagent Glenzocimab, Syk tyrosine-kinase inhibitor PRT-060318, and anti-α2β1 mAb 6F1. No direct comparison has been made of the antithrombic potential of these drugs. METHODS Using a multiparameter whole-blood microfluidic assay, we compared the effects of Revacept, 9O12-Fab, PRT-060318, or 6F1 mAb intervention with vascular collagens and collagen-related substrates with varying dependencies on GPVI and α2β1. To inform on Revacept binding to collagen, we used fluorescent-labelled anti-GPVI nanobody-28. RESULTS AND CONCLUSION In this first comparison of four inhibitors of platelet-collagen interactions with antithrombotic potential, we find that at arterial shear rate: (1) the thrombus-inhibiting effect of Revacept was restricted to highly GPVI-activating surfaces; (2) 9O12-Fab consistently but partly inhibited thrombus size on all surfaces; (3) effects of GPVI-directed interventions were surpassed by Syk inhibition; and (4) α2β1-directed intervention with 6F1 mAb was strongest for collagens where Revacept and 9O12-Fab were limitedly effective. Our data hence reveal a distinct pharmacological profile for GPVI-binding competition (Revacept), GPVI receptor blockage (9O12-Fab), GPVI signaling (PRT-060318), and α2β1 blockage (6F1 mAb) in flow-dependent thrombus formation, depending on the platelet-activating potential of the collagen substrate. This work thus points to additive antithrombotic action mechanisms of the investigated drugs.
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Affiliation(s)
- Natalie J Jooss
- Department of Biochemistry, Cardiovascular Research Institute, Maastricht University, Maastricht, The Netherlands.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Yvonne M C Henskens
- Central Diagnostic Laboratory, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Steve P Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, United Kingdom
| | - Richard W Farndale
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.,CambCol Laboratories, Ely, United Kingdom
| | - Meinrad P Gawaz
- Department of Cardiology and Angiology, University Hospital Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Martine Jandrot-Perrus
- UMR_S1148, Laboratory for Vascular Translational Science, INSERM, University Paris Cité, Paris, France
| | - Natalie S Poulter
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, United Kingdom
| | - Johan W M Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute, Maastricht University, Maastricht, The Netherlands.,Synapse Research Institute, Maastricht, The Netherlands
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3
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Bourne JH, Smith CW, Jooss NJ, Di Y, Brown HC, Montague SJ, Thomas MR, Poulter NS, Rayes J, Watson SP. CLEC-2 Supports Platelet Aggregation in Mouse but not Human Blood at Arterial Shear. Thromb Haemost 2022; 122:1988-2000. [PMID: 35817083 PMCID: PMC9718592 DOI: 10.1055/a-1896-6992] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 06/01/2022] [Indexed: 10/17/2022]
Abstract
C-type lectin-like receptor 2 (CLEC-2) is highly expressed on platelets and a subpopulation of myeloid cells, and is critical in lymphatic development. CLEC-2 has been shown to support thrombus formation at sites of inflammation, but to have a minor/negligible role in hemostasis. This identifies CLEC-2 as a promising therapeutic target in thromboinflammatory disorders, without hemostatic detriment. We utilized a GPIbα-Cre recombinase mouse for more restricted deletion of platelet-CLEC-2 than the previously used PF4-Cre mouse. clec1bfl/flGPIbα-Cre+ mice are born at a Mendelian ratio, with a mild reduction in platelet count, and present with reduced thrombus size post-FeCl3-induced thrombosis, compared to littermates. Antibody-mediated depletion of platelet count in C57BL/6 mice, to match clec1bfl/flGPIbα-Cre+ mice, revealed that the reduced thrombus size post-FeCl3-injury was due to the loss of CLEC-2, and not mild thrombocytopenia. Similarly, clec1bfl/flGPIbα-Cre+ mouse blood replenished with CLEC-2-deficient platelets ex vivo to match littermates had reduced aggregate formation when perfused over collagen at arterial flow rates. In contrast, platelet-rich thrombi formed following perfusion of human blood under flow conditions over collagen types I or III, atherosclerotic plaque, or inflammatory endothelial cells were unaltered in the presence of CLEC-2-blocking antibody, AYP1, or recombinant CLEC-2-Fc. The reduction in platelet aggregation observed in clec1bfl/flGPIbα-Cre+ mice during arterial thrombosis is mediated by the loss of CLEC-2 on mouse platelets. In contrast, CLEC-2 does not support thrombus generation on collagen, atherosclerotic plaque, or inflamed endothelial cells in human at arterial shear.
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Affiliation(s)
- Joshua H. Bourne
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Christopher W. Smith
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Natalie J. Jooss
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Ying Di
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Helena C. Brown
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Institute of Experimental Biomedicine I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany.
| | - Samantha J. Montague
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Mark R. Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- UHB and SWBH NHS Trusts, Birmingham, United Kingdom
| | - Natalie S. Poulter
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Julie Rayes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Steve P. Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, United Kingdom
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Duan R, Goldmann L, Brandl R, Spannagl M, Weber C, Siess W, von Hundelshausen P. Effects of the Btk-Inhibitors Remibrutinib (LOU064) and Rilzabrutinib (PRN1008) With Varying Btk Selectivity Over Tec on Platelet Aggregation and in vitro Bleeding Time. Front Cardiovasc Med 2021; 8:749022. [PMID: 34631841 PMCID: PMC8498029 DOI: 10.3389/fcvm.2021.749022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 08/31/2021] [Indexed: 12/02/2022] Open
Abstract
Background: Bruton tyrosine kinase inhibitors (BTKi) are used in B-cell malignancies and in development against various autoimmune diseases. Since Btk is also involved in specific pathways of platelet activation, BTKi might be considered to target platelet GPVI/GPIb-mediated atherothrombosis and platelet FcγRIIA-dependent immune disorders. However, BTKi treatment of patients with B-cell malignancies is frequently associated with mild bleeding events caused possibly by off-target inhibition of Tec. Here, we compared the platelet effects of two novel BTKi that exhibit a high (remibrutinib) or low (rilzabrutinib) selectivity for Btk over Tec. Methods and Results: Remibrutinib and rilzabrutinib were pre-incubated with anticoagulated blood. Platelet aggregation and in vitro bleeding time (closure time) were studied by multiple electrode aggregometry (MEA) and platelet-function analyzer-200 (PFA-200), respectively. Both BTKi inhibited atherosclerotic plaque-stimulated GPVI-mediated platelet aggregation, remibrutinib being more potent (IC50 = 0.03 μM) than rilzabrutinib (IC50 = 0.16 μM). Concentrations of remibrutinib (0.1 μM) and rilzabrutinib (0.5 μM), >80% inhibitory for plaque-induced aggregation, also significantly suppressed (>90%) the Btk-dependent pathways of platelet aggregation upon GPVI, von Willebrand factor/GPIb and FcγRIIA activation stimulated by low collagen concentrations, ristocetin and antibody cross-linking, respectively. Both BTKi did not inhibit aggregation stimulated by ADP, TRAP-6 or arachidonic acid. Remibrutinib (0.1 μM) only slightly prolonged closure time and significantly less than rilzabrutinib (0.5 μM). Conclusion: Remibrutinib and rilzabrutinib inhibit Btk-dependent pathways of platelet aggregation upon GPVI, VWF/GPIb, and FcγRIIA activation. Remibrutinib being more potent and showing a better profile of inhibition of Btk-dependent platelet activation vs. hemostatic impairment than rilzabrutinib may be considered for further development as an antiplatelet drug.
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Affiliation(s)
- Rundan Duan
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany
| | - Luise Goldmann
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany
| | - Richard Brandl
- Institute for Vascular Surgery and Phlebology am Marienplatz, Munich, Germany
| | - Michael Spannagl
- Department of Transfusion Medicine, Cell Therapeutics and Hemostaseology, Ludwig-Maximilians University, Munich, Germany
| | - Christian Weber
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany.,German Centre for Cardiovascular Research, Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK), Partner Site Munich Heart Alliance, Munich, Germany.,Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Wolfgang Siess
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany.,German Centre for Cardiovascular Research, Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - Philipp von Hundelshausen
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany.,German Centre for Cardiovascular Research, Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
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5
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Wang L, Tang C. Targeting Platelet in Atherosclerosis Plaque Formation: Current Knowledge and Future Perspectives. Int J Mol Sci 2020; 21:ijms21249760. [PMID: 33371312 PMCID: PMC7767086 DOI: 10.3390/ijms21249760] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/09/2020] [Accepted: 12/16/2020] [Indexed: 12/23/2022] Open
Abstract
Besides their role in hemostasis and thrombosis, it has become increasingly clear that platelets are also involved in many other pathological processes of the vascular system, such as atherosclerotic plaque formation. Atherosclerosis is a chronic vascular inflammatory disease, which preferentially develops at sites under disturbed blood flow with low speeds and chaotic directions. Hyperglycemia, hyperlipidemia, and hypertension are all risk factors for atherosclerosis. When the vascular microenvironment changes, platelets can respond quickly to interact with endothelial cells and leukocytes, participating in atherosclerosis. This review discusses the important roles of platelets in the plaque formation under pro-atherogenic factors. Specifically, we discussed the platelet behaviors under disturbed flow, hyperglycemia, and hyperlipidemia conditions. We also summarized the molecular mechanisms involved in vascular inflammation during atherogenesis based on platelet receptors and secretion of inflammatory factors. Finally, we highlighted the studies of platelet migration in atherogenesis. In general, we elaborated an atherogenic role of platelets and the aspects that should be further studied in the future.
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Affiliation(s)
- Lei Wang
- Cyrus Tang Hematology Center, Cyrus Tang Medical Institute, Soochow University, Suzhou 215123, China;
| | - Chaojun Tang
- Cyrus Tang Hematology Center, Cyrus Tang Medical Institute, Soochow University, Suzhou 215123, China;
- Collaborative Innovation Center of Hematology of Jiangsu Province, Soochow University, Suzhou 215123, China
- National Clinical Research Center for Hematologic Diseases, the First Affiliated Hospital of Soochow University, Suzhou 215123, China
- Correspondence: ; Tel.: +86-512-6588-0899
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Glycoprotein VI (GPVI)-functionalized nanoparticles targeting arterial injury sites under physiological flow. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2020; 29:102274. [PMID: 32712174 DOI: 10.1016/j.nano.2020.102274] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/31/2022]
Abstract
Thrombus formation at athero-thrombotic sites is initiated by the exposure of collagen followed by platelet adhesion mediated by the platelet-specific collagen receptor glycoprotein VI (GPVI). Here, dimeric GPVI was used as a targeting motif to functionalize polymeric nanoparticle-based drug carriers and to show that with proper design, such GPVI-coated nanoparticles (GPNs) can efficiently and specifically target arterial injury sites while withstanding physiological flow. In a microfluidic model, under physiological shear levels (1-40 dyne/cm2), 200 nm and 2 μm GPNs exhibited a >60 and >10-fold increase in binding to collagen compared to control particles, respectively. In vitro experiments in an arterial stenosis injury model, subjected to physiological pulsatile flow, showed shear-enhanced adhesion of 200 nm GPNs at the stenosis region which was confirmed in vivo in a mice ligation carotid injury model using intravital microscopy. Altogether, our results illustrate how engineering tools can be harnessed to design nano-carriers that efficiently target cardiovascular disease sites.
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7
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Agarwal G, Smith AW, Jones B. Discoidin domain receptors: Micro insights into macro assemblies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118496. [PMID: 31229648 DOI: 10.1016/j.bbamcr.2019.06.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/19/2022]
Abstract
Assembly of cell-surface receptors into specific oligomeric states and/or clusters before and after ligand binding is an important feature governing their biological function. Receptor oligomerization can be mediated by specific domains of the receptor, ligand binding, configurational changes or other interacting molecules. In this review we summarize our understanding of the oligomeric state of discoidin domain receptors (DDR1 and DDR2), which belong to the receptor tyrosine kinase family (RTK). DDRs form an interesting system from an oligomerization perspective as their ligand collagen(s) can also undergo supramolecular assembly to form fibrils. Even though DDR1 and DDR2 differ in the domains responsible to form ligand-free dimers they share similarities in binding to soluble, monomeric collagen. However, only DDR1b forms globular clusters in response to monomeric collagen and not DDR2. Interestingly, both DDR1 and DDR2 are assembled into linear clusters by the collagen fibril. Formation of these clusters is important for receptor phosphorylation and is mediated in part by other membrane components. We summarize how the oligomeric status of DDRs shares similarities with other members of the RTK family and with collagen receptors. Unraveling the multiple macro-molecular configurations adopted by this receptor-ligand pair can provide novel insights into the intricacies of cell-matrix interactions.
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Affiliation(s)
- Gunjan Agarwal
- Biomedical Engineering Department, The Ohio State University, Columbus, OH 43210, USA.
| | - Adam W Smith
- Department of Chemistry, University of Akron, Akron, OH 44325, USA
| | - Blain Jones
- Biomedical Engineering Department, The Ohio State University, Columbus, OH 43210, USA
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Abstract
Superresolution microscopy has become increasingly widespread over the past 5 years and allows users to image biological processes below the diffraction limit of traditional fluorescence microscopy where resolution is restricted to approximately 250 nm. Superresolution refers to a wide range of techniques which employ different approaches to circumvent the diffraction limit. Two of these approaches, structured illumination microscopy (SIM) and single-molecule localization microscopy (SMLM), which provide a doubling and tenfold increase in resolution respectively, are dominating the field. This is partly because of the insights into biology they offer and partly because of their commercialization by the main microscope manufacturers. This chapter provides background to the two techniques, practical considerations for their use, and protocols for their application to platelet biology.
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9
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Degen H, Borst O, Ziegler M, Mojica Munoz AK, Jamasbi J, Walker B, Göbel S, Fassbender J, Adler K, Brandl R, Münch G, Lorenz R, Siess W, Gawaz M, Ungerer M. ADPase CD39 Fused to Glycoprotein VI-Fc Boosts Local Antithrombotic Effects at Vascular Lesions. J Am Heart Assoc 2017; 6:JAHA.117.005991. [PMID: 28751543 PMCID: PMC5586441 DOI: 10.1161/jaha.117.005991] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND GPVI (Glycoprotein VI) is the essential platelet collagen receptor in atherothrombosis. Dimeric GPVI-Fc (Revacept) binds to GPVI binding sites on plaque collagen. As expected, it did not increase bleeding in clinical studies. GPVI-Fc is a potent inhibitor of atherosclerotic plaque-induced platelet aggregation at high shear flow, but its inhibition at low shear flow is limited. We sought to increase the platelet inhibitory potential by fusing GPVI-Fc to the ectonucleotidase CD39 (fusion protein GPVI-CD39), which inhibits local ADP accumulation at vascular plaques, and thus to create a lesion-directed dual antiplatelet therapy that is expected to lack systemic bleeding risks. METHODS AND RESULTS GPVI-CD39 effectively stimulated local ADP degradation and, compared with GPVI-Fc alone, led to significantly increased inhibition of ADP-, collagen-, and human plaque-induced platelet aggregation in Multiplate aggregometry and plaque-induced platelet thrombus formation under arterial flow conditions. GPVI-CD39 did not increase bleeding time in an in vitro assay simulating primary hemostasis. In a mouse model of ferric chloride-induced arterial thrombosis, GPVI-CD39 effectively delayed vascular thrombosis but did not increase tail bleeding time in vivo. CONCLUSIONS GPVI-CD39 is a novel approach to increase local antithrombotic activity at sites of atherosclerotic plaque rupture or injury. It enhances GPVI-Fc-mediated platelet inhibition and presents a potentially effective and safe molecule for the treatment of acute atherothrombotic events, with a favorable risk-benefit ratio.
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Affiliation(s)
| | - Oliver Borst
- Medical Clinic III, University of Tübingen, Germany
| | | | | | - Janina Jamasbi
- IPEK - Institute for Prevention of Cardiovascular Diseases, University of Munich, Germany
| | | | | | | | | | - Richard Brandl
- St. Mary's Square Institute for Vascular Surgery and Phlebology, Munich, Germany
| | - Götz Münch
- advanceCOR - Procorde, Martinsried, Germany
| | - Reinhard Lorenz
- IPEK - Institute for Prevention of Cardiovascular Diseases, University of Munich, Germany
| | - Wolfgang Siess
- IPEK - Institute for Prevention of Cardiovascular Diseases, University of Munich, Germany.,DZHK (German Centre for Cardiovascular Research) partner site Munich Heart Alliance, Munich, Germany
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10
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Poulter NS, Pollitt AY, Owen DM, Gardiner EE, Andrews RK, Shimizu H, Ishikawa D, Bihan D, Farndale RW, Moroi M, Watson SP, Jung SM. Clustering of glycoprotein VI (GPVI) dimers upon adhesion to collagen as a mechanism to regulate GPVI signaling in platelets. J Thromb Haemost 2017; 15:549-564. [PMID: 28058806 PMCID: PMC5347898 DOI: 10.1111/jth.13613] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Indexed: 01/01/2023]
Abstract
Essentials Dimeric high-affinity collagen receptor glycoprotein VI (GPVI) is present on resting platelets. Spatio-temporal organization of platelet GPVI-dimers was evaluated using advanced microscopy. Upon platelet adhesion to collagenous substrates, GPVI-dimers coalesce to form clusters. Clustering of GPVI-dimers may increase avidity and facilitate platelet activation SUMMARY: Background Platelet glycoprotein VI (GPVI) binding to subendothelial collagen exposed upon blood vessel injury initiates thrombus formation. Dimeric GPVI has high affinity for collagen, and occurs constitutively on resting platelets. Objective To identify higher-order oligomerization (clustering) of pre-existing GPVI dimers upon interaction with collagen as a mechanism to initiate GPVI-mediated signaling. Methods GPVI was located by use of fluorophore-conjugated GPVI dimer-specific Fab (antigen-binding fragment). The tested substrates include Horm collagen I fibers, soluble collagen III, GPVI-specific collagen peptides, and fibrinogen. GPVI dimer clusters on the platelet surface interacting with these substrates were visualized with complementary imaging techniques: total internal reflection fluorescence microscopy to monitor real-time interactions, and direct stochastic optical reconstruction microscopy (dSTORM), providing relative quantification of GPVI cluster size and density. Confocal microscopy was used to locate GPVI dimer clusters, glycoprotein Ib, integrin α2 β1 , and phosphotyrosine. Results Upon platelet adhesion to all collagenous substrates, GPVI dimers coalesced to form clusters; notably clusters formed along the fibers of Horm collagen. dSTORM revealed that GPVI density within clusters depended on the substrate, collagen III being the most effective. Clusters on fibrinogen-adhered platelets were much smaller and more numerous; whether these are pre-existing oligomers of GPVI dimers or fibrinogen-induced is not clear. Some GPVI dimer clusters colocalized with areas of phosphotyrosine, indicative of signaling activity. Integrin α2 β1 was localized to collagen fibers close to GPVI dimer clusters. GPVI clustering depends on a dynamic actin cytoskeleton. Conclusions Platelet adhesion to collagen induces GPVI dimer clustering. GPVI clustering increases both avidity for collagen and the proximity of GPVI-associated signaling molecules, which may be crucial for the initiation and persistence of signaling.
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Affiliation(s)
- N. S. Poulter
- Institute of Cardiovascular SciencesCollege of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
- Centre for Membrane Proteins and Receptors (COMPARE)College of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
| | - A. Y. Pollitt
- Institute of Cardiovascular SciencesCollege of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
- Present address: Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingRG6 6ASUK
| | - D. M. Owen
- Department of Physics and Randall Division of Cell and Molecular BiophysicsKing's College LondonLondonUK
| | - E. E. Gardiner
- Department of Cancer Biology and TherapeuticsJohn Curtin School of Medical ResearchAustralian National UniversityCanberraACTAustralia
| | - R. K. Andrews
- Australian Centre for Blood DiseasesMonash UniversityMelbourneVictoriaAustralia
| | - H. Shimizu
- Research DepartmentChemo‐Sero‐Therapeutic Research InstituteKaketsukenKumamotoJapan
| | - D. Ishikawa
- Research DepartmentChemo‐Sero‐Therapeutic Research InstituteKaketsukenKumamotoJapan
| | - D. Bihan
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - R. W. Farndale
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - M. Moroi
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - S. P. Watson
- Institute of Cardiovascular SciencesCollege of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
- Centre for Membrane Proteins and Receptors (COMPARE)College of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
| | - S. M. Jung
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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