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Abstract
Platelets are megakaryocyte-derived cellular fragments, which lack a nucleus and are the smallest circulating cells and are classically known to have a major role in supporting hemostasis. Apart from this well-established role, it is now becoming evident that platelets are also capable of conveying other important functions, such as during infection and inflammation. This paper will outline these nonhemostatic functions in two major sections termed "Platelets versus pathogens" and "Platelet-target cell communication". Platelets actively contribute to protection against invading pathogens and are capable of regulating immune functions in various target cells, all through sophisticated and efficient mechanisms. These relatively novel features will be highlighted, illustrating the multifunctional role of platelets in inflammation.
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Affiliation(s)
- Rick Kapur
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael׳s Hospital, Canadian Blood Services, Toronto, Ontario, Canada
| | - John W Semple
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael׳s Hospital, Canadian Blood Services, Toronto, Ontario, Canada; Departments of Pharmacology, Medicine, and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
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252
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Platelet protective efficacy of 3,4,5 trisubstituted isoxazole analogue by inhibiting ROS-mediated apoptosis and platelet aggregation. Mol Cell Biochem 2016; 414:137-51. [DOI: 10.1007/s11010-016-2667-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/11/2016] [Indexed: 12/23/2022]
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253
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Krishna S, Dodd CA, Filipov NM. Behavioral and monoamine perturbations in adult male mice with chronic inflammation induced by repeated peripheral lipopolysaccharide administration. Behav Brain Res 2016; 302:279-90. [PMID: 26802725 DOI: 10.1016/j.bbr.2016.01.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/27/2015] [Accepted: 01/17/2016] [Indexed: 02/07/2023]
Abstract
Considering the limited information on the ability of chronic peripheral inflammation to induce behavioral alterations, including on their persistence after inflammatory stimuli termination and on associated neurochemical perturbations, this study assessed the effects of chronic (0.25 mg/kg; i.p.; twice weekly) lipopolysaccharide (LPS) treatment on selected behavioral, neurochemical and molecular measures at different time points in adult male C57BL/6 mice. Behaviorally, LPS-treated mice were hypoactive after 6 weeks, whereas significant hyperactivity was observed after 12 weeks of LPS and 11 weeks after 13 week LPS treatment termination. Similar biphasic responses, i.e., early decrease followed by a delayed increase were observed in the open field test center time, suggestive of, respectively, increased and decreased anxiety. In a forced swim test, mice exhibited increased immobility (depressive behavior) at all times they were tested. Chronic LPS also produced persistent increase in splenic serotonin (5-HT) and time-dependent, brain region-specific alterations in striatal and prefrontocortical dopamine and 5-HT homeostasis. Microglia, but not astrocytes, were activated by LPS early and late, but their activation did not persist after LPS treatment termination. Above findings demonstrate that chronic peripheral inflammation initially causes hypoactivity and increased anxiety, followed by persistent hyperactivity and decreased anxiety. Notably, chronic LPS-induced depressive behavior appears early, persists long after LPS termination, and is associated with increased splenic 5-HT. Collectively, our data highlight the need for a greater focus on the peripheral/central monoamine alterations and lasting behavioral deficits induced by chronic peripheral inflammation as there are many pathological conditions where inflammation of a chronic nature is a hallmark feature.
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Affiliation(s)
- Saritha Krishna
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Celia A Dodd
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Nikolay M Filipov
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
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254
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Kapur R, Zufferey A, Boilard E, Semple JW. Nouvelle cuisine: platelets served with inflammation. THE JOURNAL OF IMMUNOLOGY 2015; 194:5579-87. [PMID: 26048965 DOI: 10.4049/jimmunol.1500259] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Platelets are small cellular fragments with the primary physiological role of maintaining hemostasis. In addition to this well-described classical function, it is becoming increasingly clear that platelets have an intimate connection with infection and inflammation. This stems from several platelet characteristics, including their ability to bind infectious agents and secrete many immunomodulatory cytokines and chemokines, as well as their expression of receptors for various immune effector and regulatory functions, such as TLRs, which allow them to sense pathogen-associated molecular patterns. Furthermore, platelets contain RNA that can be nascently translated under different environmental stresses, and they are able to release membrane microparticles that can transport inflammatory cargo to inflammatory cells. Interestingly, acute infections can also result in platelet breakdown and thrombocytopenia. This report highlights these relatively new aspects of platelets and, thus, their nonhemostatic nature in an inflammatory setting.
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Affiliation(s)
- Rick Kapur
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Canadian Blood Services, Toronto, Ontario M5B 1W8, Canada
| | - Anne Zufferey
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
| | - Eric Boilard
- Centre de Recherche en Rhumatologie et Immunologie, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Faculté de Médecine de l'Université Laval, Quebec City, Quebec G1V 4G2, Canada
| | - John W Semple
- Toronto Platelet Immunobiology Group, Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Canadian Blood Services, Toronto, Ontario M5B 1W8, Canada; Department of Pharmacology, University of Toronto, Toronto, Ontario M5B 1W8, Canada; Department of Medicine, University of Toronto, Toronto, Ontario M5B 1W8, Canada; and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5B 1W8, Canada
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255
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256
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Garraud O. Editorial: Platelets as Immune Cells in Physiology and Immunopathology. Front Immunol 2015; 6:274. [PMID: 26089822 PMCID: PMC4453471 DOI: 10.3389/fimmu.2015.00274] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 05/18/2015] [Indexed: 12/12/2022] Open
Affiliation(s)
- Olivier Garraud
- EA3064, University of Lyon Saint-Etienne , Saint-Etienne , France ; Institut National de la Transfusion Sanguine (INTS) , Paris , France
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257
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Schrottmaier WC, Kral JB, Badrnya S, Assinger A. Aspirin and P2Y12 Inhibitors in platelet-mediated activation of neutrophils and monocytes. Thromb Haemost 2015; 114:478-89. [PMID: 25904241 DOI: 10.1160/th14-11-0943] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/28/2015] [Indexed: 01/19/2023]
Abstract
Platelets are key players in haemostasis and represent a pivotal link between inflammation, immunity and atherogenesis. Depending on the (patho)physiological environment platelets modulate various leukocyte functions via release of inflammatory mediators and direct cell-cell interactions. Elevated levels of circulating platelet-leukocyte aggregates are found in patients suffering from several thrombotic or inflammatory conditions. Platelet-monocyte and platelet-neutrophil interaction can trigger pro- and anti-inflammatory responses and modulate effector functions of all leukocyte subpopulations. These platelet-mediated immune responses have implications for the progression of cardiovascular diseases and also play a crucial role during infections, cancer, transplantations and other inflammatory diseases of several organs. Antiplatelet therapy including the COX inhibitor aspirin and/or ADP receptor P2Y12 inhibitors such as clopidogrel, prasugrel and ticagrelor are the therapy of choice for various cardiovascular complications. Both aspirin and P2Y12 inhibitors attenuate platelet-leukocyte interactions, thereby also modulating immune responses. This may have beneficial effects in some pathological conditions, while it might be detrimental in others. This review aims to summarise the current knowledge on platelet-leukocyte interactions and the impact of aspirin and P2Y12 inhibition on platelet-mediated immune responses and to give an overview on the effects of antiplatelet therapy on platelet-leukocyte interplay in various diseases.
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Affiliation(s)
| | | | | | - Alice Assinger
- Dr. Alice Assinger, Centre for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria, Tel.: +43 1 40160 31405, E-mail:
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258
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Nording HM, Seizer P, Langer HF. Platelets in inflammation and atherogenesis. Front Immunol 2015; 6:98. [PMID: 25798138 PMCID: PMC4351644 DOI: 10.3389/fimmu.2015.00098] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/19/2015] [Indexed: 12/12/2022] Open
Abstract
Platelets contribute to processes beyond thrombus formation and may play a so far underestimated role as an immune cell in various circumstances. This review outlines immune functions of platelets in host defense, but also how they may contribute to mechanisms of infectious diseases. A particular emphasis is placed on the interaction of platelets with other immune cells. Furthermore, this article outlines the features of atherosclerosis as an inflammatory vascular disease highlighting the role of platelet crosstalk with cellular and soluble factors involved in atheroprogression. Understanding, how platelets influence these processes of vascular remodeling will shed light on their role for tissue homeostasis beyond intravascular thrombosis. Finally, translational implications of platelet-mediated inflammation in atherosclerosis are discussed.
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Affiliation(s)
- Henry M. Nording
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
- Section for Cardioimmunology, Eberhard Karls-University Tübingen, Tübingen, Germany
| | - Peter Seizer
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
| | - Harald F. Langer
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
- Section for Cardioimmunology, Eberhard Karls-University Tübingen, Tübingen, Germany
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