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Ellis ML, Terreaux A, Alwis I, Smythe R, Perdomo J, Eckly A, Cranmer SL, Passam FH, Maclean J, Schoenwaelder SM, Ruggeri ZM, Lanza F, Taoudi S, Yuan Y, Jackson SP. GPIbα-filamin A interaction regulates megakaryocyte localization and budding during platelet biogenesis. Blood 2024; 143:342-356. [PMID: 37922495 DOI: 10.1182/blood.2023021292] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/27/2023] [Accepted: 10/24/2023] [Indexed: 11/05/2023] Open
Abstract
ABSTRACT Glycoprotein Ibα (GPIbα) is expressed on the surface of platelets and megakaryocytes (MKs) and anchored to the membrane skeleton by filamin A (flnA). Although GPIb and flnA have fundamental roles in platelet biogenesis, the nature of this interaction in megakaryocyte biology remains ill-defined. We generated a mouse model expressing either human wild-type (WT) GPIbα (hGPIbαWT) or a flnA-binding mutant (hGPIbαFW) and lacking endogenous mouse GPIbα. Mice expressing the mutant GPIbα transgene exhibited macrothrombocytopenia with preserved GPIb surface expression. Platelet clearance was normal and differentiation of MKs to proplatelets was unimpaired in hGPIbαFW mice. The most striking abnormalities in hGPIbαFW MKs were the defective formation of the demarcation membrane system (DMS) and the redistribution of flnA from the cytoplasm to the peripheral margin of MKs. These abnormalities led to disorganized internal MK membranes and the generation of enlarged megakaryocyte membrane buds. The defective flnA-GPIbα interaction also resulted in misdirected release of buds away from the vasculature into bone marrow interstitium. Restoring the linkage between flnA and GPIbα corrected the flnA redistribution within MKs and DMS ultrastructural defects as well as restored normal bud size and release into sinusoids. These studies define a new mechanism of macrothrombocytopenia resulting from dysregulated MK budding. The link between flnA and GPIbα is not essential for the MK budding process, however, it plays a major role in regulating the structure of the DMS, bud morphogenesis, and the localized release of buds into the circulation.
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Affiliation(s)
- Marc L Ellis
- Thrombosis Research Group, The Heart Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Antoine Terreaux
- Blood Cell Formation Lab, Walter and Eliza Hall Institute, Parkville, VIC, Australia
| | - Imala Alwis
- Thrombosis Research Group, The Heart Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Rhyll Smythe
- Thrombosis Research Group, The Heart Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Jose Perdomo
- Haematology Research Unit, St George and Sutherland Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Anita Eckly
- Université de Strasbourg, INSERM, French Blood Establishment (EFS) Grand Est, BPPS UMR-S 1255, FMTS, Strasbourg, France
| | - Susan L Cranmer
- Eastern Health Clinical School, Monash University, Box Hill, VIC, Australia
| | - Freda H Passam
- Thrombosis Research Group, The Heart Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Jessica Maclean
- Thrombosis Research Group, The Heart Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Simone M Schoenwaelder
- Thrombosis Research Group, The Heart Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
| | - Zaverio M Ruggeri
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA
| | - Francois Lanza
- Université de Strasbourg, INSERM, French Blood Establishment (EFS) Grand Est, BPPS UMR-S 1255, FMTS, Strasbourg, France
| | - Samir Taoudi
- Blood Cell Formation Lab, Walter and Eliza Hall Institute, Parkville, VIC, Australia
- The University of Melbourne, Parkville, VIC, Australia
| | - Yuping Yuan
- Thrombosis Research Group, The Heart Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Shaun P Jackson
- Thrombosis Research Group, The Heart Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA
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Sokolovskaya AA, Popov MA, Sergeeva EA, Metelkin AA, Zybin DI, Shumakov DV, Kubatiev AA. Investigation of Platelet Apoptosis in Patients after Surgical Myocardial Revascularization. Biomedicines 2023; 11:251. [PMID: 36830787 PMCID: PMC9952963 DOI: 10.3390/biomedicines11020251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/13/2023] [Accepted: 01/15/2023] [Indexed: 01/19/2023] Open
Abstract
Platelets are one of the main participants in vascular accidents in cases of coronary heart disease (CHD). In this study, we sought to detect platelet apoptosis in patients with coronary artery disease who underwent scheduled myocardial revascularization surgery. To identify apoptotic events, we analyzed phosphatidylserine (PS) expression on the surface of platelets and mitochondrial membrane potential (ΔΨm) by flow cytometry in two groups of 30 patients aged 45-60 years: Group 1-patients before myocardial revascularization surgery and group 2-patients after myocardial revascularization surgery. The control group consisted of 10 healthy volunteers aged 45-60 years. According to our data, the percentage levels of PS expression in patients greatly decreased after surgery. We confirmed platelet apoptosis by recording depolarization of ΔΨm in pre- and postoperative patients. ΔΨm readings were considerably improved after surgery. Our data indicated that the functional parameters of platelets in patients with coronary heart disease differed from the characteristics of platelets in patients who underwent myocardial revascularization, and from those of patients in a control group. Future studies of platelet phenotypic characteristics and platelet apoptosis biomarkers should greatly advance our understanding of the pathophysiology of coronary heart disease, and further promote the development of methods for predicting adverse outcomes after surgery.
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Affiliation(s)
- Alisa A. Sokolovskaya
- Department of Molecular and Cellular Pathophysiology, Research Institute of General Pathology and Pathophysiology, Baltiyskaya 8, 125315 Moscow, Russia
| | - Mikhail A. Popov
- Department of Cardiosurgery, Vladimirsky Moscow Regional Research Clinical Institute, Shepkina 61/2, 129110 Moscow, Russia
| | - Ekaterina A. Sergeeva
- Department of Molecular and Cellular Pathophysiology, Research Institute of General Pathology and Pathophysiology, Baltiyskaya 8, 125315 Moscow, Russia
| | - Arkadiy A. Metelkin
- Department of Molecular and Cellular Pathophysiology, Research Institute of General Pathology and Pathophysiology, Baltiyskaya 8, 125315 Moscow, Russia
| | - Dmitry I. Zybin
- Department of Cardiosurgery, Vladimirsky Moscow Regional Research Clinical Institute, Shepkina 61/2, 129110 Moscow, Russia
| | - Dmitry V. Shumakov
- Department of Cardiosurgery, Vladimirsky Moscow Regional Research Clinical Institute, Shepkina 61/2, 129110 Moscow, Russia
| | - Aslan A. Kubatiev
- Department of Molecular and Cellular Pathophysiology, Research Institute of General Pathology and Pathophysiology, Baltiyskaya 8, 125315 Moscow, Russia
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3
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Wu YH, Chen HY, Hong WC, Wei CY, Pang JHS. Carboplatin-Induced Thrombocytopenia through JAK2 Downregulation, S-Phase Cell Cycle Arrest and Apoptosis in Megakaryocytes. Int J Mol Sci 2022; 23:ijms23116290. [PMID: 35682967 PMCID: PMC9181531 DOI: 10.3390/ijms23116290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/28/2022] [Accepted: 06/02/2022] [Indexed: 02/01/2023] Open
Abstract
Chemotherapy-induced thrombocytopenia (CIT) is a common complication when treating malignancies with cytotoxic agents wherein carboplatin is one of the most typical agents causing CIT. Janus kinase 2 (JAK2) is one of the critical enzymes to megakaryocyte proliferation and differentiation. However, the role of the JAK2 in CIT remains unclear. In this study, we used both carboplatin-induced CIT mice and MEG-01 cell line to examine the expression of JAK2 and signal transducer and activator of transcription 3 (STAT3) pathway. Under CIT, the expression of JAK2 was significantly reduced in vivo and in vitro. More surprisingly, the JAK2/STAT3 pathway remained inactivated even when thrombopoietin (TPO) was administered. On the other hand, carboplatin could cause prominent S phase cell cycle arrest and markedly increased apoptosis in MEG-01 cells. These results showed that the thrombopoiesis might be interfered through the downregulation of JAK2/STAT3 pathway by carboplatin in CIT, and the fact that exogenous TPO supplement cannot reactivate this pathway.
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Affiliation(s)
- Yi-Hong Wu
- Department of Chinese Medicine, Chang Gung Memorial Hospital, Guishan, Taoyuan 333, Taiwan; (Y.-H.W.); (H.-Y.C.); (W.-C.H.); (C.-Y.W.)
- School of Traditional Chinese Medicine, Chang Gung University, Guishan, Taoyuan 333, Taiwan
| | - Hsing-Yu Chen
- Department of Chinese Medicine, Chang Gung Memorial Hospital, Guishan, Taoyuan 333, Taiwan; (Y.-H.W.); (H.-Y.C.); (W.-C.H.); (C.-Y.W.)
- School of Traditional Chinese Medicine, Chang Gung University, Guishan, Taoyuan 333, Taiwan
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Guishan, Taoyuan 333, Taiwan
| | - Wei-Chin Hong
- Department of Chinese Medicine, Chang Gung Memorial Hospital, Guishan, Taoyuan 333, Taiwan; (Y.-H.W.); (H.-Y.C.); (W.-C.H.); (C.-Y.W.)
| | - Chen-Ying Wei
- Department of Chinese Medicine, Chang Gung Memorial Hospital, Guishan, Taoyuan 333, Taiwan; (Y.-H.W.); (H.-Y.C.); (W.-C.H.); (C.-Y.W.)
| | - Jong-Hwei Su Pang
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Guishan, Taoyuan 333, Taiwan
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Guishan, Taoyuan 333, Taiwan
- Correspondence: ; Tel.: +886-3-2118800 (ext. 3482); Fax: +886-3-2118800 (ext. 3484)
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Marini I, Uzun G, Jamal K, Bakchoul T. Treatment of drug-induced immune thrombocytopenias. Haematologica 2022; 107:1264-1277. [PMID: 35642486 PMCID: PMC9152960 DOI: 10.3324/haematol.2021.279484] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Indexed: 01/19/2023] Open
Abstract
Several therapeutic agents can cause thrombocytopenia by either immune-mediated or non-immune-mediated mechanisms. Non-immune-mediated thrombocytopenia is due to direct toxicity of drug molecules to platelets or megakaryocytes. Immune-mediated thrombocytopenia, on the other hand, involves the formation of antibodies that react to platelet-specific glycoprotein complexes, as in classic drug-induced immune thrombocytopenia (DITP), or to platelet factor 4, as in heparin-induced thrombocytopenia (HIT) and vaccine-induced immune thrombotic thrombocytopenia (VITT). Clinical signs include a rapid drop in platelet count, bleeding or thrombosis. Since the patient's condition can deteriorate rapidly, prompt diagnosis and management are critical. However, the necessary diagnostic tests are only available in specialized laboratories. Therefore, the most demanding step in treatment is to identify the agent responsible for thrombocytopenia, which often proves difficult because many patients are taking multiple medications and have comorbidities that can themselves also cause thrombocytopenia. While DITP is commonly associated with an increased risk of bleeding, HIT and VITT have a high mortality rate due to the high incidence of thromboembolic complications. A structured approach to drug-associated thrombocytopenia/thrombosis can lead to successful treatment and a lower mortality rate. In addition to describing the treatment of DITP, HIT, VITT, and vaccine-associated immune thrombocytopenia, this review also provides the pathophysiological and clinical information necessary for correct patient management.
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Affiliation(s)
- Irene Marini
- Centre for Clinical Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen
| | - Gunalp Uzun
- Centre for Clinical Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen
| | - Kinan Jamal
- Centre for Clinical Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen
| | - Tamam Bakchoul
- Centre for Clinical Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen.
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5
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Kuter DJ. Treatment of chemotherapy-induced thrombocytopenia in patients with non-hematologic malignancies. Haematologica 2022; 107:1243-1263. [PMID: 35642485 PMCID: PMC9152964 DOI: 10.3324/haematol.2021.279512] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Indexed: 01/19/2023] Open
Abstract
Chemotherapy-induced thrombocytopenia (CIT) is a common complication of the treatment of non-hematologic malignancies. Many patient-related variables (e.g., age, tumor type, number of prior chemotherapy cycles, amount of bone marrow tumor involvement) determine the extent of CIT. CIT is related to the type and dose of chemotherapy, with regimens containing gemcitabine, platinum, or temozolomide producing it most commonly. Bleeding and the need for platelet transfusions in CIT are rather uncommon except in patients with platelet counts below 25x109/L in whom bleeding rates increase significantly and platelet transfusions are the only treatment. Nonetheless, platelet counts below 70x109/L present a challenge. In patients with such counts, it is important to exclude other causes of thrombocytopenia (medications, infection, thrombotic microangiopathy, post-transfusion purpura, coagulopathy and immune thrombocytopenia). If these are not present, the common approach is to reduce chemotherapy dose intensity or switch to other agents. Unfortunately decreasing relative dose intensity is associated with reduced tumor response and remission rates. Thrombopoietic growth factors (recombinant human thrombopoietin, pegylated human megakaryocyte growth and development factor, romiplostim, eltrombopag, avatrombopag and hetrombopag) improve pretreatment and nadir platelet counts, reduce the need for platelet transfusions, and enable chemotherapy dose intensity to be maintained. National Comprehensive Cancer Network guidelines permit their use but their widespread adoption awaits adequate phase III randomized, placebo-controlled studies demonstrating maintenance of relative dose intensity, reduction of platelet transfusions and bleeding, and possibly improved survival. Their potential appropriate use also depends on consensus by the oncology community as to what constitutes an appropriate pretreatment platelet count as well as identification of patient-related and treatment variables that might predict bleeding.
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Affiliation(s)
- David J Kuter
- Massachusetts General Hospital, Harvard Medical School, Boston, MA.
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6
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Wright JR, Jones S, Parvathy S, Kaczmarek LK, Forsythe I, Farndale RW, Gibbins JM, Mahaut-Smith MP. The voltage-gated K + channel Kv1.3 modulates platelet motility and α 2β 1 integrin-dependent adhesion to collagen. Platelets 2022; 33:451-461. [PMID: 34348571 PMCID: PMC8935947 DOI: 10.1080/09537104.2021.1942818] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/03/2021] [Accepted: 06/03/2021] [Indexed: 12/13/2022]
Abstract
Kv1.3 is a voltage-gated K+-selective channel with roles in immunity, insulin-sensitivity, neuronal excitability and olfaction. Despite being one of the largest ionic conductances of the platelet surface membrane, its contribution to platelet function is poorly understood. Here we show that Kv1.3-deficient platelets display enhanced ADP-evoked platelet aggregation and secretion, and an increased surface expression of platelet integrin αIIb. In contrast, platelet adhesion and thrombus formation in vitro under arterial shear conditions on surfaces coated with collagen were reduced for samples from Kv1.3-/- compared to wild type mice. Use of collagen-mimetic peptides revealed a specific defect in the engagement with α2β1. Kv1.3-/- platelets developed significantly fewer, and shorter, filopodia than wild type platelets during adhesion to collagen fibrils. Kv1.3-/- mice displayed no significant difference in thrombus formation within cremaster muscle arterioles using a laser-induced injury model, thus other pro-thrombotic pathways compensate in vivo for the adhesion defect observed in vitro. This may include the increased platelet counts of Kv1.3-/- mice, due in part to a prolonged lifespan. The ability of Kv1.3 to modulate integrin-dependent platelet adhesion has important implications for understanding its contribution to normal physiological platelet function in addition to its reported roles in auto-immune diseases and thromboinflammatory models of stroke.
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Affiliation(s)
- Joy R Wright
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Sarah Jones
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
- Department of Life Sciences, Manchester Metropolitan University, Manchester, UK
| | - Sasikumar Parvathy
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, UK
| | - Leonard K Kaczmarek
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, USA
| | - Ian Forsythe
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | | | - Jonathan M Gibbins
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, UK
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7
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The necroptotic cell death pathway operates in megakaryocytes, but not in platelet synthesis. Cell Death Dis 2021; 12:133. [PMID: 33510145 PMCID: PMC7843594 DOI: 10.1038/s41419-021-03418-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 02/06/2023]
Abstract
Necroptosis is a pro-inflammatory cell death program executed by the terminal effector, mixed lineage kinase domain-like (MLKL). Previous studies suggested a role for the necroptotic machinery in platelets, where loss of MLKL or its upstream regulator, RIPK3 kinase, impacted thrombosis and haemostasis. However, it remains unknown whether necroptosis operates within megakaryocytes, the progenitors of platelets, and whether necroptotic cell death might contribute to or diminish platelet production. Here, we demonstrate that megakaryocytes possess a functional necroptosis signalling cascade. Necroptosis activation leads to phosphorylation of MLKL, loss of viability and cell swelling. Analyses at steady state and post antibody-mediated thrombocytopenia revealed that platelet production was normal in the absence of MLKL, however, platelet activation and haemostasis were impaired with prolonged tail re-bleeding times. We conclude that MLKL plays a role in regulating platelet function and haemostasis and that necroptosis signalling in megakaryocytes is dispensable for platelet production.
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Martínez-Botía P, Acebes-Huerta A, Seghatchian J, Gutiérrez L. On the Quest for In Vitro Platelet Production by Re-Tailoring the Concepts of Megakaryocyte Differentiation. ACTA ACUST UNITED AC 2020; 56:medicina56120671. [PMID: 33287459 PMCID: PMC7761839 DOI: 10.3390/medicina56120671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 11/26/2020] [Accepted: 11/30/2020] [Indexed: 12/14/2022]
Abstract
The demand of platelet transfusions is steadily growing worldwide, inter-donor variation, donor dependency, or storability/viability being the main contributing factors to the current global, donor-dependent platelet concentrate shortage concern. In vitro platelet production has been proposed as a plausible alternative to cover, at least partially, the increasing demand. However, in practice, such a logical production strategy does not lack complexity, and hence, efforts are focused internationally on developing large scale industrial methods and technologies to provide efficient, viable, and functional platelet production. This would allow obtaining not only sufficient numbers of platelets but also functional ones fit for all clinical purposes and civil scenarios. In this review, we cover the evolution around the in vitro culture and differentiation of megakaryocytes into platelets, the progress made thus far to bring the culture concept from basic research towards good manufacturing practices certified production, and subsequent clinical trial studies. However, little is known about how these in vitro products should be stored or whether any safety measure should be implemented (e.g., pathogen reduction technology), as well as their quality assessment (how to isolate platelets from the rest of the culture cells, debris, microvesicles, or what their molecular and functional profile is). Importantly, we highlight how the scientific community has overcome the old dogmas and how the new perspectives influence the future of platelet-based therapy for transfusion purposes.
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Affiliation(s)
- Patricia Martínez-Botía
- Platelet Research Lab, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain; (P.M.-B.); (A.A.-H.)
- Department of Medicine, University of Oviedo, 33003 Oviedo, Spain
| | - Andrea Acebes-Huerta
- Platelet Research Lab, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain; (P.M.-B.); (A.A.-H.)
| | - Jerard Seghatchian
- International Consultancy in Strategic Safety/Quality Improvements of Blood-Derived Bioproducts and Suppliers Quality Audit/Inspection, London NW3 3AA, UK;
| | - Laura Gutiérrez
- Platelet Research Lab, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain; (P.M.-B.); (A.A.-H.)
- Department of Medicine, University of Oviedo, 33003 Oviedo, Spain
- Correspondence:
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Nevzorova TA, Mordakhanova ER, Daminova AG, Ponomareva AA, Andrianova IA, Le Minh G, Rauova L, Litvinov RI, Weisel JW. Platelet factor 4-containing immune complexes induce platelet activation followed by calpain-dependent platelet death. Cell Death Discov 2019; 5:106. [PMID: 31263574 PMCID: PMC6591288 DOI: 10.1038/s41420-019-0188-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/29/2019] [Accepted: 06/05/2019] [Indexed: 01/23/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is a complication of heparin therapy sometimes associated with thrombosis. The hallmark of HIT is antibodies to the heparin/platelet factor 4 (PF4) complex that cause thrombocytopenia and thrombosis through platelet activation. Despite the clinical importance, the molecular mechanisms and late consequences of immune platelet activation are not fully understood. Here, we studied immediate and delayed effects of the complexes formed by human PF4 and HIT-like monoclonal mouse anti-human-PF4/heparin IgG antibodies (named KKO) on isolated human platelets in vitro. Direct platelet-activating effect of the KKO/PF4 complexes was corroborated by the overexpression of phosphatidylserine (PS) and P-selectin on the platelet surface. The immune platelet activation was accompanied by a decrease of the mitochondrial transmembrane potential (ΔΨm), concurrent with a significant gradual reduction of the ATP content in platelets, indicating disruption of energy metabolism. A combination of PS expression and mitochondrial depolarization induced by the PF4-containing immune complexes observed in a substantial fraction of platelets was considered as a sign of ongoing platelet death, as opposed to a subpopulation of activated live platelets with PS on the plasma membrane but normal ΔΨm. Both activated and dying platelets treated with KKO/PF4 formed procoagulant extracellular microvesicles bearing PS on their surface. Scanning and transmission electron microscopy revealed dramatic morphological changes of KKO/PF4-treated platelets, including their fragmentation, another indicator of cell death. Most of the effects of KKO/PF4 were prevented by an anti-FcγRII monoclonal antibody IV.3. The adverse functional and structural changes in platelets induced by the KKO/PF4 complexes were associated with strong time-dependent activation of calpain, but only trace cleavage of caspase 3. The results indicate that the pathogenic PF4-containing HIT-like immune complexes induce direct prothrombotic platelet activation via FcγRIIA receptors followed by non-apoptotic calpain-dependent death of platelets, which can be an important mechanism of thrombocytopenia during HIT development.
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Affiliation(s)
- Tatiana A. Nevzorova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russian Federation 420008 Russia
| | - Elmira R. Mordakhanova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russian Federation 420008 Russia
| | - Amina G. Daminova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russian Federation 420008 Russia
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky str., Kazan, Russian Federation 420111 Russia
| | - Anastasia A. Ponomareva
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russian Federation 420008 Russia
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky str., Kazan, Russian Federation 420111 Russia
| | - Izabella A. Andrianova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russian Federation 420008 Russia
| | - Giang Le Minh
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russian Federation 420008 Russia
| | - Lubica Rauova
- Children’s Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104 USA
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, 3401 Civic Center Blvd, Philadelphia, PA 19104 USA
| | - Rustem I. Litvinov
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russian Federation 420008 Russia
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, 421 Curie Boulevard, Philadelphia, PA 19104 USA
| | - John W. Weisel
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., Kazan, Russian Federation 420008 Russia
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, 421 Curie Boulevard, Philadelphia, PA 19104 USA
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Ijaz SH, Jamal SM, Qayyum R. Relationship Between Thyroid Hormone Levels and Mean Platelet Count and Volume: Quantitative Assessment. Cureus 2018; 10:e3421. [PMID: 30546973 PMCID: PMC6289553 DOI: 10.7759/cureus.3421] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background The hormones of the hypophysis-thyroid axis (HTA), thyroid stimulating hormone (TSH), and thyroid hormones, L-thyroxine (T4) and 3, 3′, 5-L-triiodothyronine (T3), modulate the metabolism, differentiation, and proliferation of almost every cell in the body. Several studies have examined the effect of HTA hormones on platelet count and mean platelet volume (MPV), but have reported inconsistent results. Our aim was to examine the association between HTA hormones and platelet count and MPV in a large cohort of the adult population of the United States. Methods We used the continuous National Health and Nutritional Examination Survey (NHANES) which made available data on HTA hormones (1999-2000, 2001-2002, 2007-2008, 2009-2010, and 2011-2012) to examine the association between HTA hormones and platelet count and MPV. Analyses were performed with adjustments for the complex survey sampling methods of NHANES data. Unadjusted and adjusted generalized linear regressions were performed to examine the relationship between HTA hormones and platelet count and MPV. Regression models were adjusted for age, sex, race, alcohol use, smoking status, serum c-reactive protein, red blood cell folate, diabetes mellitus, glomerular filtration rate, body mass index, and hypertension. Results Of the 10,619 individuals eligible for inclusion in the analyses, 5,267 (49.6%) were females and 2,132 (20.08%) were African Americans. The mean ± standard deviation of platelet count was 256.4 ± 67.1 109/L, MPV 8.04 ± 0.92 fL, serum T4 7.92 ± 1.68 mg/dL, and serum T3 114.08 ± 24.6 ng/dL. In unadjusted analyses, an increase in the serum levels of T4 or T3 was associated with a significant increase in the platelet count and MPV (all p-values < 0.05). In contrast, an increase in serum TSH level was associated with a significant decrease in the platelet count (p-value = 0.05) but had no effect on MPV. After adjustment for potential confounders, serum T4 levels were significantly associated with platelet count but not with MPV. Individuals in the lowest quartile of T4 had 18.73 x 109/L lower platelet count than individuals in the upper-most quartile (p-value = 0.03). Serum TSH and serum T3 levels had no effect on platelet count or MPV after adjusting for potential confounding variables. Conclusions We report that only serum T4 levels, and not TSH or T3 levels, are independently associated with platelet count and there is no independent association between HTA hormones and MPV. Our findings suggest a possible role of serum T4 on thrombopoiesis or on platelet lifespan.
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Affiliation(s)
- Sardar H Ijaz
- Internal Medicine, Oklahoma University of Health Sciences, Oklahoma City, USA
| | - Shakeel M Jamal
- Internal Medicine, Central Michigan University College of Medicine, Saginaw, USA
| | - Rehan Qayyum
- Internal Medicine, Virginia Commonwealth University, Richmond, USA
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11
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Schubert P, Johnson L, Marks DC, Devine DV. Ultraviolet-Based Pathogen Inactivation Systems: Untangling the Molecular Targets Activated in Platelets. Front Med (Lausanne) 2018; 5:129. [PMID: 29868586 PMCID: PMC5949320 DOI: 10.3389/fmed.2018.00129] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/19/2018] [Indexed: 12/13/2022] Open
Abstract
Transfusions of platelets are an important cornerstone of medicine; however, recipients may be subject to risk of adverse events associated with the potential transmission of pathogens, especially bacteria. Pathogen inactivation (PI) technologies based on ultraviolet illumination have been developed in the last decades to mitigate this risk. This review discusses studies of platelet concentrates treated with the current generation of PI technologies to assess their impact on quality, PI capacity, safety, and clinical efficacy. Improved safety seems to come with the cost of reduced platelet functionality, and hence transfusion efficacy. In order to understand these negative impacts in more detail, several molecular analyses have identified signaling pathways linked to platelet function that are altered by PI. Because some of these biochemical alterations are similar to those seen arising in the context of routine platelet storage lesion development occurring during blood bank storage, we lack a complete picture of the contribution of PI treatment to impaired platelet functionality. A model generated using data from currently available publications places the signaling protein kinase p38 as a central player regulating a variety of mechanisms triggered in platelets by PI systems.
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Affiliation(s)
- Peter Schubert
- Canadian Blood Services, Vancouver, BC, Canada.,Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Lacey Johnson
- Research and Development, Australian Red Cross Blood Service, Sydney, NSW, Australia
| | - Denese C Marks
- Research and Development, Australian Red Cross Blood Service, Sydney, NSW, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Dana V Devine
- Canadian Blood Services, Vancouver, BC, Canada.,Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
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12
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Serebruany V. Viewpoint: Reversible nature of platelet binding causing transfusion-related acute lung injury (TRALI) syndrome may explain dyspnea after ticagrelor and elinogrel. Thromb Haemost 2017; 108:1024-7. [DOI: 10.1160/th12-03-0180] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 05/07/2012] [Indexed: 11/05/2022]
Abstract
SummaryThere may be a universal mechanism explaining dyspnea after ticagrelor and elinogrel, namely, transfusion-related acute lung injury (TRALI). Indeed, recent clinical trials with ticagrelor (DISPERSE, DISPERSE-II, and PLATO), and elinogrel (INNOVATE PCI) revealed double-digit rates of dyspnea after novel reversible antiplatelet agents. In contrast, dyspnea is not associated with conventional non-reversible agents such as aspirin, or thienopyridines (ticlopidine, clopidogrel, or prasugrel) suggesting distinct mechanism of shortness of breath after ticagrelor and elinogrel. The adenosine hypothesis has been offered to explain such adverse association. However, despite obvious similarity between ticagrelor and adenosine molecules, the chemical structure of elinogrel is entirely different. In fact, ticagrelor is a cyclopentyl-triazolo-pyrimidine, while elinogrel is a quinazolinedione. Since both agents cause dyspnea, the adenosine hypothesis is no longer valid. In contrast, the reversible nature of platelet inhibition attributable to both ticagrelor and elinogrel causing premature cell ageing, apoptosis, impaired turnover due to sequestration of overloaded, exhausted platelets in the pulmonary circulation are among potential autoimmune mechanism(s) resulting in the development of a TRALI-like reaction, and frequent dyspnea. Despite expected benefit for better bleeding control, further development of reversible antithrombins is severely limited due to the existence of a potentially universal serious adverse event, such as TRALI-syndrome with dyspnea as a predominant clinical manifestation. Since TRALI is an established number one contributor to mortality after blood transfusions, ticagrelor death “benefit”in PLATO is challenged further.
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13
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Pleines I, Woods J, Chappaz S, Kew V, Foad N, Ballester-Beltrán J, Aurbach K, Lincetto C, Lane RM, Schevzov G, Alexander WS, Hilton DJ, Astle WJ, Downes K, Nurden P, Westbury SK, Mumford AD, Obaji SG, Collins PW, Delerue F, Ittner LM, Bryce NS, Holliday M, Lucas CA, Hardeman EC, Ouwehand WH, Gunning PW, Turro E, Tijssen MR, Kile BT. Mutations in tropomyosin 4 underlie a rare form of human macrothrombocytopenia. J Clin Invest 2017; 127:814-829. [PMID: 28134622 PMCID: PMC5330761 DOI: 10.1172/jci86154] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 12/01/2016] [Indexed: 01/12/2023] Open
Abstract
Platelets are anuclear cells that are essential for blood clotting. They are produced by large polyploid precursor cells called megakaryocytes. Previous genome-wide association studies in nearly 70,000 individuals indicated that single nucleotide variants (SNVs) in the gene encoding the actin cytoskeletal regulator tropomyosin 4 (TPM4) exert an effect on the count and volume of platelets. Platelet number and volume are independent risk factors for heart attack and stroke. Here, we have identified 2 unrelated families in the BRIDGE Bleeding and Platelet Disorders (BPD) collection who carry a TPM4 variant that causes truncation of the TPM4 protein and segregates with macrothrombocytopenia, a disorder characterized by low platelet count. N-Ethyl-N-nitrosourea–induced (ENU-induced) missense mutations in Tpm4 or targeted inactivation of the Tpm4 locus led to gene dosage–dependent macrothrombocytopenia in mice. All other blood cell counts in Tpm4-deficient mice were normal. Insufficient TPM4 expression in human and mouse megakaryocytes resulted in a defect in the terminal stages of platelet production and had a mild effect on platelet function. Together, our findings demonstrate a nonredundant role for TPM4 in platelet biogenesis in humans and mice and reveal that truncating variants in TPM4 cause a previously undescribed dominant Mendelian platelet disorder.
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Affiliation(s)
- Irina Pleines
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Joanne Woods
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Stephane Chappaz
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Verity Kew
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Nicola Foad
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - José Ballester-Beltrán
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Katja Aurbach
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Wuerzburg, Wuerzburg, Germany
| | - Chiara Lincetto
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Rachael M. Lane
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Galina Schevzov
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Warren S. Alexander
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Douglas J. Hilton
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - William J. Astle
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Kate Downes
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Paquita Nurden
- Institut Hospitalo-Universitaire LIRYC, Plateforme Technologique d’Innovation Biomédicale, Hôpital Xavier Arnozan, Pessac, France
| | - Sarah K. Westbury
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Andrew D. Mumford
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Samya G. Obaji
- Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom
| | - Peter W. Collins
- Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom
| | - NIHR BioResource
- NIHR BioResource–Rare Diseases, Cambridge University Hospitals, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Fabien Delerue
- Transgenic Animal Unit, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, Australia
| | - Lars M. Ittner
- Transgenic Animal Unit, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, Australia
| | - Nicole S. Bryce
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Mira Holliday
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Christine A. Lucas
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Edna C. Hardeman
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Willem H. Ouwehand
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NIHR BioResource–Rare Diseases, Cambridge University Hospitals, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Peter W. Gunning
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Ernest Turro
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge, United Kingdom
| | - Marloes R. Tijssen
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Benjamin T. Kile
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
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14
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ÇEVİK Ö, ADIGÜZEL Z, BAYKAL AT, ŞENER A. Tumor necrosis factor-alpha induced caspase-3 activation-related iNOS gene expression in ADP-activated platelets. Turk J Biol 2017. [DOI: 10.3906/biy-1509-64] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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15
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Abstract
The BCL2-selective BH3 mimetic venetoclax was recently approved for the treatment of relapsed, chromosome 17p-deleted chronic lymphocytic leukemia (CLL) and is undergoing extensive testing, alone and in combination, in lymphomas, acute leukemias, and solid tumors. Here we summarize recent advances in understanding of the biology of BCL2 family members that shed light on the action of BH3 mimetics, review preclinical and clinical studies leading to the regulatory approval of venetoclax, and discuss future investigation of this new class of antineoplastic agent.
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Affiliation(s)
- Haiming Dai
- Division of Oncology Research , Mayo Clinic, Rochester, MN, 55905, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA.,Center for Medical Physics and Technology, Hefei Institute of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
| | - X Wei Meng
- Division of Oncology Research , Mayo Clinic, Rochester, MN, 55905, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Scott H Kaufmann
- Division of Oncology Research , Mayo Clinic, Rochester, MN, 55905, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
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16
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Lebois M, Dowling MR, Gangatirkar P, Hodgkin PD, Kile BT, Alexander WS, Josefsson EC. Regulation of platelet lifespan in the presence and absence of thrombopoietin signaling. J Thromb Haemost 2016; 14:1882-7. [PMID: 27344013 DOI: 10.1111/jth.13397] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Indexed: 01/09/2023]
Abstract
UNLABELLED Essentials We examined platelet survival in models of absent or enhanced thrombopoietin (TPO) signaling. Platelet lifespan is normal in transgenic mice with chronically enhanced TPO signaling. Mpl deficiency does not negatively affect platelet lifespan in the absence of thrombocytopenia. We conclude that TPO and its receptor Mpl are dispensable for platelet survival in adult mice. SUMMARY Background It is well established that thrombopoietin (TPO), acting via its receptor Mpl, is the major cytokine regulator of platelet biogenesis. The primary mechanism by which TPO signaling stimulates thrombopoiesis is via stimulation of Mpl-expressing hematopoietic progenitors; Mpl on megakaryocytes and platelets acts to control the amount of TPO available. TPO could potentially reduce platelet and/or megakaryocyte apoptosis, and therefore increase the platelet count. However, the effect of TPO receptor signaling on platelet survival is unresolved. Methods and results Here, we investigated platelet survival in mouse models of absent or enhanced TPO signaling. In the absence of thrombocytopenia, Mpl deficiency did not negatively influence platelet lifespan, and nor was platelet survival affected in transgenic mice with chronically increased TPO signaling. Conclusions We conclude that TPO and its receptor Mpl are dispensable for platelet survival in adult mice.
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Affiliation(s)
- M Lebois
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - M R Dowling
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - P Gangatirkar
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - P D Hodgkin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - B T Kile
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - W S Alexander
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - E C Josefsson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.
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17
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Alvarez-Diaz S, Dillon CP, Lalaoui N, Tanzer MC, Rodriguez DA, Lin A, Lebois M, Hakem R, Josefsson EC, O'Reilly LA, Silke J, Alexander WS, Green DR, Strasser A. The Pseudokinase MLKL and the Kinase RIPK3 Have Distinct Roles in Autoimmune Disease Caused by Loss of Death-Receptor-Induced Apoptosis. Immunity 2016; 45:513-526. [PMID: 27523270 DOI: 10.1016/j.immuni.2016.07.016] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 05/23/2016] [Accepted: 06/06/2016] [Indexed: 12/12/2022]
Abstract
The kinases RIPK1 and RIPK3 and the pseudo-kinase MLKL have been identified as key regulators of the necroptotic cell death pathway, although a role for MLKL within the whole animal has not yet been established. Here, we have shown that MLKL deficiency rescued the embryonic lethality caused by loss of Caspase-8 or FADD. Casp8(-/-)Mlkl(-/-) and Fadd(-/-)Mlkl(-/-) mice were viable and fertile but rapidly developed severe lymphadenopathy, systemic autoimmune disease, and thrombocytopenia. These morbidities occurred more rapidly and with increased severity in Casp8(-/-)Mlkl(-/-) and Fadd(-/-)Mlkl(-/-) mice compared to Casp8(-/-)Ripk3(-/-) or Fadd(-/-)Ripk3(-/-) mice, respectively. These results demonstrate that MLKL is an essential effector of aberrant necroptosis in embryos caused by loss of Caspase-8 or FADD. Furthermore, they suggest that RIPK3 and/or MLKL may exert functions independently of necroptosis. It appears that non-necroptotic functions of RIPK3 contribute to the lymphadenopathy, autoimmunity, and excess cytokine production that occur when FADD or Caspase-8-mediated apoptosis is abrogated.
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Affiliation(s)
- Silvia Alvarez-Diaz
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3050, Australia
| | - Christopher P Dillon
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Najoua Lalaoui
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3050, Australia
| | - Maria C Tanzer
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3050, Australia
| | - Diego A Rodriguez
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ann Lin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Marion Lebois
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Razq Hakem
- Ontario Cancer Institute, University Health Network, and Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 2M9, Canada
| | - Emma C Josefsson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3050, Australia
| | - Lorraine A O'Reilly
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3050, Australia
| | - John Silke
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3050, Australia
| | - Warren S Alexander
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3050, Australia.
| | - Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Andreas Strasser
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3050, Australia.
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18
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Lee EF, Grabow S, Chappaz S, Dewson G, Hockings C, Kluck RM, Debrincat MA, Gray DH, Witkowski MT, Evangelista M, Pettikiriarachchi A, Bouillet P, Lane RM, Czabotar PE, Colman PM, Smith BJ, Kile BT, Fairlie WD. Physiological restraint of Bak by Bcl-xL is essential for cell survival. Genes Dev 2016; 30:1240-50. [PMID: 27198225 PMCID: PMC4888843 DOI: 10.1101/gad.279414.116] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 04/18/2016] [Indexed: 12/21/2022]
Abstract
Lee et al. describe a mutation in mouse and human Bak that specifically disrupts its interaction with the prosurvival protein Bcl-xL. In vivo, loss of Bcl-xL binding to Bak led to significant defects in T-cell and blood platelet survival. Due to the myriad interactions between prosurvival and proapoptotic members of the Bcl-2 family of proteins, establishing the mechanisms that regulate the intrinsic apoptotic pathway has proven challenging. Mechanistic insights have primarily been gleaned from in vitro studies because genetic approaches in mammals that produce unambiguous data are difficult to design. Here we describe a mutation in mouse and human Bak that specifically disrupts its interaction with the prosurvival protein Bcl-xL. Substitution of Glu75 in mBak (hBAK Q77) for leucine does not affect the three-dimensional structure of Bak or killing activity but reduces its affinity for Bcl-xL via loss of a single hydrogen bond. Using this mutant, we investigated the requirement for physical restraint of Bak by Bcl-xL in apoptotic regulation. In vitro, BakQ75L cells were significantly more sensitive to various apoptotic stimuli. In vivo, loss of Bcl-xL binding to Bak led to significant defects in T-cell and blood platelet survival. Thus, we provide the first definitive in vivo evidence that prosurvival proteins maintain cellular viability by interacting with and inhibiting Bak.
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Affiliation(s)
- Erinna F Lee
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia; Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia; Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria 3084, Australia; School of Cancer Medicine, La Trobe University, Melbourne, Victoria 3084, Australia
| | - Stephanie Grabow
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Stephane Chappaz
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Grant Dewson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Colin Hockings
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ruth M Kluck
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Marlyse A Debrincat
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Daniel H Gray
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Matthew T Witkowski
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Marco Evangelista
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria 3084, Australia; School of Cancer Medicine, La Trobe University, Melbourne, Victoria 3084, Australia
| | - Anne Pettikiriarachchi
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Philippe Bouillet
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Rachael M Lane
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Peter M Colman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Brian J Smith
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Benjamin T Kile
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - W Douglas Fairlie
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia; Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia; Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria 3084, Australia; School of Cancer Medicine, La Trobe University, Melbourne, Victoria 3084, Australia
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19
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Debrincat MA, Pleines I, Lebois M, Lane RM, Holmes ML, Corbin J, Vandenberg CJ, Alexander WS, Ng AP, Strasser A, Bouillet P, Sola-Visner M, Kile BT, Josefsson EC. BCL-2 is dispensable for thrombopoiesis and platelet survival. Cell Death Dis 2015; 6:e1721. [PMID: 25880088 PMCID: PMC4650559 DOI: 10.1038/cddis.2015.97] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 02/25/2015] [Accepted: 03/03/2015] [Indexed: 01/28/2023]
Abstract
Navitoclax (ABT-263), an inhibitor of the pro-survival BCL-2 family proteins BCL-2, BCL-XL and BCL-W, has shown clinical efficacy in certain BCL-2-dependent haematological cancers, but causes dose-limiting thrombocytopaenia. The latter effect is caused by Navitoclax directly inducing the apoptotic death of platelets, which are dependent on BCL-XL for survival. Recently, ABT-199, a selective BCL-2 antagonist, was developed. It has shown promising anti-leukaemia activity in patients whilst sparing platelets, suggesting that the megakaryocyte lineage does not require BCL-2. In order to elucidate the role of BCL-2 in megakaryocyte and platelet survival, we generated mice with a lineage-specific deletion of Bcl2, alone or in combination with loss of Mcl1 or Bclx. Platelet production and platelet survival were analysed. Additionally, we made use of BH3 mimetics that selectively inhibit BCL-2 or BCL-XL. We show that the deletion of BCL-2, on its own or in concert with MCL-1, does not affect platelet production or platelet lifespan. Thrombocytopaenia in Bclx-deficient mice was not affected by additional genetic loss or pharmacological inhibition of BCL-2. Thus, BCL-2 is dispensable for thrombopoiesis and platelet survival in mice.
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Affiliation(s)
- M A Debrincat
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
| | - I Pleines
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
| | - M Lebois
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
| | - R M Lane
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
| | - M L Holmes
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
| | - J Corbin
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
| | - C J Vandenberg
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
| | - W S Alexander
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
| | - A P Ng
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
| | - A Strasser
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
| | - P Bouillet
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
| | - M Sola-Visner
- Boston Children's Hospital, Division of Newborn Medicine, Boston, MA, USA
| | - B T Kile
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
| | - E C Josefsson
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, VIC, Australia
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Yu S, Huang H, Deng G, Xie Z, Ye Y, Guo R, Cai X, Hong J, Qian D, Zhou X, Tao Z, Chen B, Li Q. miR-326 targets antiapoptotic Bcl-xL and mediates apoptosis in human platelets. PLoS One 2015; 10:e0122784. [PMID: 25875481 PMCID: PMC4395162 DOI: 10.1371/journal.pone.0122784] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 02/15/2015] [Indexed: 12/20/2022] Open
Abstract
Platelets play crucial roles in hemostasis, thrombosis, wound healing, inflammation, angiogenesis, and tumor metastases. Because they are anucleated blood cells, platelets lack nuclear DNA, but they do contain mitochondrial DNA, which plays a key role in regulating apoptosis. Recent evidence has suggested that miRNAs are also involved in regulating gene expression and apoptosis in platelets. Our previous study showed that the expression of miR-326 increased visibly when apheresis platelets were stored in vitro. The antiapoptotic Bcl-2 family regulator Bcl-xL has been identified as a putative target of miR-326. In the present study, dual reporter luciferase assays were used to characterize the function of miR-326 in the regulation of the apoptosis of platelet cells. These assays demonstrated that miR-326 bound to the 3′-translated region of Bcl-xL. To directly assess the functional effects of miR-326 expression, levels of Bcl-xL and the apoptotic status of stored apheresis platelets were measured after transfection of miR-326 mimic or inhibitor. Results indicated that miR-326 inhibited Bcl-xL expression and induced apoptosis in stored platelets. Additionally, miR-326 inhibited Bcl-2 protein expression and enhanced Bak expression, possibly through an indirect mechanism, though there was no effect on the expression of Bax. The effect of miR-326 appeared to be limited to apoptosis, with no significant effect on platelet activation. These results provide new insight into the molecular mechanisms affecting differential platelet gene regulation, which may increase understanding of the role of platelet apoptosis in multiple diseases.
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Affiliation(s)
- Shifang Yu
- The Department of Transfusion Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
- The Department of Transfusion Medicine, The First Affiliated Hospital of the Wenzhou Medical University, Wenzhou, China
| | - Huicong Huang
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Gang Deng
- The Ningbo Central Blood Station, Ningbo, China
| | - Zuoting Xie
- The Department of Transfusion Medicine, The First Affiliated Hospital of the Wenzhou Medical University, Wenzhou, China
| | - Yincai Ye
- The Department of Transfusion Medicine, The First Affiliated Hospital of the Wenzhou Medical University, Wenzhou, China
| | - Ruide Guo
- The Department of Transfusion Medicine, The First Affiliated Hospital of the Wenzhou Medical University, Wenzhou, China
| | - Xuejiao Cai
- The Department of Transfusion Medicine, The First Affiliated Hospital of the Wenzhou Medical University, Wenzhou, China
| | - Junying Hong
- The Department of Transfusion Medicine, The First Affiliated Hospital of the Wenzhou Medical University, Wenzhou, China
| | - Dingliang Qian
- The Department of Laboratory Medicine, The Third Affiliated Hospital of the Wenzhou Medical University, Ruian, China
| | - Xiangjing Zhou
- The Department of Transfusion Medicine, The First Affiliated Hospital of the Wenzhou Medical University, Wenzhou, China
| | - Zhihua Tao
- The Department of Transfusion Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
- * E-mail: (QL); (ZT)
| | - Bile Chen
- The Department of Transfusion Medicine, The First Affiliated Hospital of the Wenzhou Medical University, Wenzhou, China
| | - Qiang Li
- The Department of Laboratory Medicine, The Third Affiliated Hospital of the Wenzhou Medical University, Ruian, China
- * E-mail: (QL); (ZT)
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Hamzeh-Cognasse H, Damien P, Chabert A, Pozzetto B, Cognasse F, Garraud O. Platelets and infections - complex interactions with bacteria. Front Immunol 2015; 6:82. [PMID: 25767472 PMCID: PMC4341565 DOI: 10.3389/fimmu.2015.00082] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/11/2015] [Indexed: 12/29/2022] Open
Abstract
Platelets can be considered sentinels of vascular system due to their high number in the circulation and to the range of functional immunoreceptors they express. Platelets express a wide range of potential bacterial receptors, including complement receptors, FcγRII, Toll-like receptors but also integrins conventionally described in the hemostatic response, such as GPIIb–IIIa or GPIb. Bacteria bind these receptors either directly, or indirectly via fibrinogen, fibronectin, the first complement C1q, the von Willebrand Factor, etc. The fate of platelet-bound bacteria is questioned. Several studies reported the ability of activated platelets to internalize bacteria such as Staphylococcus aureus or Porphyromonas gingivalis, though there is no clue on what happens thereafter. Are they sheltered from the immune system in the cytoplasm of platelets or are they lysed? Indeed, while the presence of phagolysosome has not been demonstrated in platelets, they contain antimicrobial peptides that were shown to be efficient on S. aureus. Besides, the fact that bacteria can bind to platelets via receptors involved in hemostasis suggests that they may induce aggregation; this has indeed been described for Streptococcus sanguinis, S. epidermidis, or C. pneumoniae. On the other hand, platelets are able to display an inflammatory response to an infectious triggering. We, and others, have shown that platelet release soluble immunomodulatory factors upon stimulation by bacterial components. Moreover, interactions between bacteria and platelets are not limited to only these two partners. Indeed, platelets are also essential for the formation of neutrophil extracellular traps by neutrophils, resulting in bacterial clearance by trapping bacteria and concentrating antibacterial factors but in enhancing thrombosis. In conclusion, the platelet–bacteria interplay is a complex game; its fine analysis is complicated by the fact that the inflammatory component adds to the aggregation response.
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Affiliation(s)
| | - Pauline Damien
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Adrien Chabert
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Bruno Pozzetto
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Fabrice Cognasse
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France ; Etablissement Français du Sang Auvergne-Loire , Saint-Etienne , France
| | - Olivier Garraud
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France ; Institut National de la Transfusion Sanguine , Paris , France
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22
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Shi DS, Smith MCP, Campbell RA, Zimmerman PW, Franks ZB, Kraemer BF, Machlus KR, Ling J, Kamba P, Schwertz H, Rowley JW, Miles RR, Liu ZJ, Sola-Visner M, Italiano JE, Christensen H, Kahr WHA, Li DY, Weyrich AS. Proteasome function is required for platelet production. J Clin Invest 2014; 124:3757-66. [PMID: 25061876 DOI: 10.1172/jci75247] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 06/05/2014] [Indexed: 01/03/2023] Open
Abstract
The proteasome inhibiter bortezomib has been successfully used to treat patients with relapsed multiple myeloma; however, many of these patients become thrombocytopenic, and it is not clear how the proteasome influences platelet production. Here we determined that pharmacologic inhibition of proteasome activity blocks proplatelet formation in human and mouse megakaryocytes. We also found that megakaryocytes isolated from mice deficient for PSMC1, an essential subunit of the 26S proteasome, fail to produce proplatelets. Consistent with decreased proplatelet formation, mice lacking PSMC1 in platelets (Psmc1(fl/fl) Pf4-Cre mice) exhibited severe thrombocytopenia and died shortly after birth. The failure to produce proplatelets in proteasome-inhibited megakaryocytes was due to upregulation and hyperactivation of the small GTPase, RhoA, rather than NF-κB, as has been previously suggested. Inhibition of RhoA or its downstream target, Rho-associated protein kinase (ROCK), restored megakaryocyte proplatelet formation in the setting of proteasome inhibition in vitro. Similarly, fasudil, a ROCK inhibitor used clinically to treat cerebral vasospasm, restored platelet counts in adult mice that were made thrombocytopenic by tamoxifen-induced suppression of proteasome activity in megakaryocytes and platelets (Psmc1(fl/fl) Pdgf-Cre-ER mice). These results indicate that proteasome function is critical for thrombopoiesis, and suggest inhibition of RhoA signaling as a potential strategy to treat thrombocytopenia in bortezomib-treated multiple myeloma patients.
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23
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Platelet production proceeds independently of the intrinsic and extrinsic apoptosis pathways. Nat Commun 2014; 5:3455. [PMID: 24632563 DOI: 10.1038/ncomms4455] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 02/14/2014] [Indexed: 12/18/2022] Open
Abstract
BH3 mimetic drugs that target BCL-2 family pro-survival proteins to induce tumour cell apoptosis represent a new era in cancer therapy. Clinical trials of navitoclax (ABT-263, which targets BCL-2, BCL-XL and BCL-W) have shown great promise, but encountered dose-limiting thrombocytopenia. Recent work has demonstrated that this is due to the inhibition of BCL-XL, which is essential for platelet survival. These findings raise new questions about the established model of platelet shedding by megakaryocytes, which is thought to be an apoptotic process. Here we generate mice with megakaryocyte-specific deletions of the essential mediators of extrinsic (Caspase-8) and intrinsic (BAK/BAX) apoptosis. We show that megakaryocytes possess a Fas ligand-inducible extrinsic apoptosis pathway. However, Fas activation does not stimulate platelet production, rather, it triggers Caspase-8-mediated killing. Combined loss of Caspase-8/BAK/BAX does not impair thrombopoiesis, but can protect megakaryocytes from death in mice infected with lymphocytic choriomeningitis virus. Thus, apoptosis is dispensable for platelet biogenesis.
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Dietary α-linolenic acid increases the platelet count in ApoE-/- mice by reducing clearance. Blood 2013; 122:1026-33. [PMID: 23801636 DOI: 10.1182/blood-2013-02-484741] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Previously we reported that dietary intake of alpha-linolenic acid (ALA) reduces atherogenesis and inhibits arterial thrombosis. Here, we analyze the substantial increase in platelet count induced by ALA and the mechanisms of reduced platelet clearance. Eight-week-old male apolipoprotein E knockout (ApoE(-/-)) mice were fed a 0.21g% cholesterol diet complemented by either a high- (7.3g%) or low-ALA (0.03g%) content. Platelet counts doubled after 16 weeks of ALA feeding, whereas the bleeding time remained similar. Plasma glycocalicin and glycocalicin index were reduced, while reticulated platelets, thrombopoietin, and bone marrow megakaryocyte colony-forming units remained unchanged. Platelet contents of liver and spleen were substantially reduced, without affecting macrophage function and number. Glycoprotein Ib (GPIb) shedding, exposure of P-selectin, and activated integrin αIIbβ3 upon activation with thrombin were reduced. Dietary ALA increased the platelet count by reducing platelet clearance in the reticulo-endothelial system. The latter appears to be mediated by reduced cleavage of GPIb by tumor necrosis factor-α-converting enzyme and reduced platelet activation/expression of procoagulant signaling. Ex vivo, there was less adhesion of human platelets to von Willebrand factor under high shear conditions after ALA treatment. Thus, ALA may be a promising tool in transfusion medicine and in high turnover/high activation platelet disorders.
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25
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Garraud O, Cognasse F, Hamzeh-Cognasse H, Laradi S, Pozzetto B, Muller JY. Transfusion sanguine et inflammation. Transfus Clin Biol 2013; 20:231-8. [DOI: 10.1016/j.tracli.2013.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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