251
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Nishimura S, Nagasaki M, Kunishima S, Sawaguchi A, Sakata A, Sakaguchi H, Ohmori T, Manabe I, Italiano JE, Ryu T, Takayama N, Komuro I, Kadowaki T, Eto K, Nagai R. IL-1α induces thrombopoiesis through megakaryocyte rupture in response to acute platelet needs. ACTA ACUST UNITED AC 2015; 209:453-66. [PMID: 25963822 PMCID: PMC4427781 DOI: 10.1083/jcb.201410052] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
An alternative pathway triggering enhanced platelet release from bone marrow megakaryocytes via a rupture-based mechanism is regulated by IL-1α in response to acute platelet requirements. Intravital visualization of thrombopoiesis revealed that formation of proplatelets, which are cytoplasmic protrusions in bone marrow megakaryocytes (MKs), is dominant in the steady state. However, it was unclear whether this is the only path to platelet biogenesis. We have identified an alternative MK rupture, which entails rapid cytoplasmic fragmentation and release of much larger numbers of platelets, primarily into blood vessels, which is morphologically and temporally different than typical FasL-induced apoptosis. Serum levels of the inflammatory cytokine IL-1α were acutely elevated after platelet loss or administration of an inflammatory stimulus to mice, whereas the MK-regulator thrombopoietin (TPO) was not elevated. Moreover, IL-1α administration rapidly induced MK rupture–dependent thrombopoiesis and increased platelet counts. IL-1α–IL-1R1 signaling activated caspase-3, which reduced plasma membrane stability and appeared to inhibit regulated tubulin expression and proplatelet formation, and ultimately led to MK rupture. Collectively, it appears the balance between TPO and IL-1α determines the MK cellular programming for thrombopoiesis in response to acute and chronic platelet needs.
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Affiliation(s)
- Satoshi Nishimura
- Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Saitama 332-0012, Japan
| | - Mika Nagasaki
- Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan
| | - Shinji Kunishima
- Department of Advanced Diagnosis, Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya 460-001, Japan
| | - Akira Sawaguchi
- Department of Anatomy, Ultrastructural Cell Biology, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Asuka Sakata
- Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | | | - Tsukasa Ohmori
- Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan
| | - Ichiro Manabe
- Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan
| | - Joseph E Italiano
- Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Vascular Biology Program at Boston Children's Hospital, Harvard Medical School, Boston, MA 02215
| | - Tomiko Ryu
- Internal medicine, Social Insurance Central General Hospital, Tokyo 105-8330, Japan
| | - Naoya Takayama
- Center for iPS Cell Research and Application, Kyoto University, Kyoto 606-8507, Japan
| | - Issei Komuro
- Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan
| | - Takashi Kadowaki
- Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan Department of Cardiovascular Medicine, Translational Systems Biology and Medicine Initiative, Computational Diagnostic Radiology and Preventive Medicine, Department of Diabetes and Metabolic Diseases, The University of Tokyo, Tokyo 113-8654, Japan
| | - Koji Eto
- Center for iPS Cell Research and Application, Kyoto University, Kyoto 606-8507, Japan
| | - Ryozo Nagai
- Center for Molecular Medicine, Jichi Medical University, Tochigi 329-0498, Japan
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252
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Bernlochner I, Goedel A, Plischke C, Schüpke S, Haller B, Schulz C, Mayer K, Morath T, Braun S, Schunkert H, Siess W, Kastrati A, Laugwitz KL. Impact of immature platelets on platelet response to ticagrelor and prasugrel in patients with acute coronary syndrome. Eur Heart J 2015. [DOI: 10.1093/eurheartj/ehv326] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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253
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Ahrens I, Chen YC, Topcic D, Bode M, Haenel D, Hagemeyer CE, Seeba H, Duerschmied D, Bassler N, Jandeleit-Dahm KA, Sweet MJ, Agrotis A, Bobik A, Peter K. HMGB1 binds to activated platelets via the receptor for advanced glycation end products and is present in platelet rich human coronary artery thrombi. Thromb Haemost 2015. [PMID: 26202300 DOI: 10.1160/th14-12-1073] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
High mobility group box 1 (HMGB1) acts as both a nuclear protein that regulates gene expression, as well as a pro-inflammatory alarmin that is released from necrotic or activated cells. Recently, HMGB1-expression in human atherosclerotic plaques was identified. Therapeutic blockade of HMGB1 reduced the development of diet-induced atherosclerosis in ApoE knockout mice. Thus, we hypothesised an interaction between HMGB1 and activated platelets. Binding of recombinant HMGB1 to platelets was assessed by flow cytometry. HMGB1 bound to thrombin-activated human platelets (MFI 2.49 vs 25.01, p=0.0079). Blood from wild-type, TLR4 and RAGE knockout mice was used to determine potential HMGB1 receptors on platelets. HMGB1 bound to platelets from wild type C57Bl6 (MFI 2.64 vs 20.3, p< 0.05), and TLR4-/- mice (MFI 2.11 vs 25.65, p< 0.05) but failed to show binding to platelets from RAGE-/- mice (p > 0.05). RAGE expression on human platelets was detected by RT-PCR with mRNA extracted from highly purified platelets and confirmed by Western blot and immunofluorescence microscopy. Platelet activation increased RAGE surface expression (MFI 4.85 vs 6.74, p< 0.05). Expression of HMGB1 in human coronary artery thrombi was demonstrated by immunohistochemistry and revealed high expression levels. Platelets bind HMGB1 upon thrombin-induced activation. Platelet specific expression of RAGE could be detected at the mRNA and protein level and is involved in the binding of HMGB1. Furthermore, platelet activation up-regulates platelet surface expression of RAGE. HMGB1 is highly expressed in platelet-rich human coronary artery thrombi pointing towards a central role for HMGB1 in atherothrombosis, thereby suggesting the possibility of platelet targeted anti-inflammatory therapies for atherothrombosis.
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Affiliation(s)
- Ingo Ahrens
- PD Dr. Ingo Ahrens, Heart Center, University of Freiburg, Cardiology and Angiology I, Hugstetter Str. 55, 79106 Freiburg, Germany, E-mail:
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254
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Artificial MiRNA Knockdown of Platelet Glycoprotein lbα: A Tool for Platelet Gene Silencing. PLoS One 2015; 10:e0132899. [PMID: 26176854 PMCID: PMC4503784 DOI: 10.1371/journal.pone.0132899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 05/28/2015] [Indexed: 11/19/2022] Open
Abstract
In recent years, candidate genes and proteins implicated in platelet function have been identified by various genomic approaches. To elucidate their exact role, we aimed to develop a method to apply miRNA interference in platelet progenitor cells by using GPIbα as a proof-of-concept target protein. After in silico and in vitro screening of siRNAs targeting GPIbα (siGPIBAs), we developed artificial miRNAs (miGPIBAs), which were tested in CHO cells stably expressing GPIb-IX complex and megakaryoblastic DAMI cells. Introduction of siGPIBAs in CHO GPIb-IX cells resulted in 44 to 75% and up to 80% knockdown of GPIbα expression using single or combined siRNAs, respectively. Conversion of siGPIBAs to miGPIBAs resulted in reduced silencing efficiency, which could however be circumvented by tandem integration of two hairpins targeting different regions of GPIBA mRNA where 72% GPIbα knockdown was achieved. CHO GPIb-IX cells transfected with the miGPIBA construct displayed a significant decrease in their ability to aggregate characterized by lower aggregate numbers and size compared to control CHO GPIb-IX cells. More importantly, we successfully silenced GPIbα in differentiating megakaryoblastic DAMI cells that exhibited morphological changes associated with actin organization. In conclusion, we here report the successful use of miRNA technology to silence a platelet protein in megakaryoblastic cells and demonstrate its usefulness in functional assays. Hence, we believe that artificial miRNAs are suitable tools to unravel the role of a protein of interest in stem cells, megakaryocytes and platelets, thereby expanding their application to novel fields of basic and translational research.
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255
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Platelet microparticles are internalized in neutrophils via the concerted activity of 12-lipoxygenase and secreted phospholipase A2-IIA. Proc Natl Acad Sci U S A 2015; 112:E3564-73. [PMID: 26106157 DOI: 10.1073/pnas.1507905112] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Platelets are anucleated blood elements highly potent at generating extracellular vesicles (EVs) called microparticles (MPs). Whereas EVs are accepted as an important means of intercellular communication, the mechanisms underlying platelet MP internalization in recipient cells are poorly understood. Our lipidomic analyses identified 12(S)-hydroxyeicosatetranoic acid [12(S)-HETE] as the predominant eicosanoid generated by MPs. Mechanistically, 12(S)-HETE is produced through the concerted activity of secreted phospholipase A2 IIA (sPLA2-IIA), present in inflammatory fluids, and platelet-type 12-lipoxygenase (12-LO), expressed by platelet MPs. Platelet MPs convey an elaborate set of transcription factors and nucleic acids, and contain mitochondria. We observed that MPs and their cargo are internalized by activated neutrophils in the endomembrane system via 12(S)-HETE. Platelet MPs are found inside neutrophils isolated from the joints of arthritic patients, and are found in neutrophils only in the presence of sPLA2-IIA and 12-LO in an in vivo model of autoimmune inflammatory arthritis. Using a combination of genetically modified mice, we show that the coordinated action of sPLA2-IIA and 12-LO promotes inflammatory arthritis. These findings identify 12(S)-HETE as a trigger of platelet MP internalization by neutrophils, a mechanism highly relevant to inflammatory processes. Because sPLA2-IIA is induced during inflammation, and 12-LO expression is restricted mainly to platelets, these observations demonstrate that platelet MPs promote their internalization in recipient cells through highly regulated mechanisms.
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256
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Horizontal RNA transfer mediates platelet-induced hepatocyte proliferation. Blood 2015; 126:798-806. [PMID: 26056167 DOI: 10.1182/blood-2014-09-600312] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 06/03/2015] [Indexed: 02/07/2023] Open
Abstract
Liver regeneration is stimulated by blood platelets, but the molecular mechanisms involved are largely unexplored. Although platelets are anucleate, they do contain coding or regulatory RNAs that can be functional within the platelet or, after transfer, in other cell types. Here, we show that platelets and platelet-like particles (PLPs) derived from the megakaryoblastic cell line MEG-01 stimulate proliferation of HepG2 cells. Platelets or PLPs were internalized within 1 hour by HepG2 cells and accumulated in the perinuclear region of the hepatocyte. Platelet internalization also occurred following a partial hepatectomy in mice. Annexin A5 blocked platelet internalization and HepG2 proliferation. We labeled total RNA of MEG-01 cells by incorporation of 5-ethynyluridine (EU) and added EU-labeled PLPs to HepG2 cells. PLP-derived RNA was detected in the cytoplasm of the HepG2 cell. We next generated PLPs containing green fluorescent protein (GFP)-tagged actin messenger RNA. PLPs did not synthesize GFP, but in coculture with HepG2 cells, significant GFP protein synthesis was demonstrated. RNA-degrading enzymes partly blocked the stimulating effect of platelets on hepatocyte proliferation. Thus, platelets stimulate hepatocyte proliferation via a mechanism that is dependent on platelet internalization by hepatocytes followed by functional transfer of RNA stored in the anucleate platelet. This mechanism may contribute to platelet-mediated liver regeneration.
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257
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Abstract
Platelets are generated from nucleated precursors referred to as megakaryocytes. The formation of platelets is one of the most elegant and unique developmental processes in eukaryotes. Because they enter the circulation without nuclei, platelets are often considered simple, non-complex cells that have limited functions beyond halting blood flow. However, emerging evidence over the past decade demonstrates that platelets are more sophisticated than previously considered. Platelets carry a rich repertoire of messenger RNAs (mRNAs), microRNAs (miRNAs), and proteins that contribute to primary (adhesion, aggregation, secretion) and alternative (immune regulation, RNA transfer, translation) functions. It is also becoming increasingly clear that the 'genetic code' of platelets changes with race, genetic disorders, or disease. Changes in the 'genetic code' can occur at multiple points including megakaryocyte development, platelet formation, or in circulating platelets. This review focuses on regulation of the 'genetic code' in megakaryocytes and platelets and its potential contribution to health and disease.
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Affiliation(s)
- M T Rondina
- The Molecular Medicine Program and Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - A S Weyrich
- The Molecular Medicine Program and Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
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258
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Dengue virus binding and replication by platelets. Blood 2015; 126:378-85. [PMID: 25943787 DOI: 10.1182/blood-2014-09-598029] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 04/28/2015] [Indexed: 02/07/2023] Open
Abstract
Dengue virus (DENV) infection causes ∼200 million cases of severe flulike illness annually, escalating to life-threatening hemorrhagic fever or shock syndrome in ∼500,000. Although thrombocytopenia is typical of both mild and severe diseases, the mechanism triggering platelet reduction is incompletely understood. As a probable initiating event, direct purified DENV-platelet binding was followed in the current study by quantitative reverse transcription-polymerase chain reaction and confirmed antigenically. Approximately 800 viruses specifically bound per platelet at 37°C. Fewer sites were observed at 25°C, the blood bank storage temperature (∼350 sites), or 4°C, known to attenuate virus cell entry (∼200 sites). Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and heparan sulfate proteoglycan were implicated as coreceptors because only the combination of anti-DC-SIGN and low-molecular-weight heparin prevented binding. Interestingly, at 37°C and 25°C, platelets replicated the positive sense single-stranded RNA genome of DENV by up to ∼4-fold over 7 days. Further time course experiments demonstrated production of viral NS1 protein, which is known to be highly antigenic in patient serum. The infectivity of DENV intrinsically decayed in vitro, which was moderated by platelet-mediated generation of viable progeny. This was shown using a transcription inhibitor and confirmed by freeze-denatured platelets being incapable of replicating the DENV genome. For the first time, these data demonstrate that platelets directly bind DENV saturably and produce infectious virus. Thus, expression of antigen encoded by DENV is a novel consideration in the pathogen-induced thrombocytopenia mechanism. These results furthermore draw attention to the possibility that platelets may produce permissive RNA viruses in addition to DENV.
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259
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Thrombocytopenia in Dengue: Interrelationship between Virus and the Imbalance between Coagulation and Fibrinolysis and Inflammatory Mediators. Mediators Inflamm 2015; 2015:313842. [PMID: 25999666 PMCID: PMC4427128 DOI: 10.1155/2015/313842] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 01/22/2015] [Indexed: 01/15/2023] Open
Abstract
Dengue is an infectious disease caused by dengue virus (DENV). In general, dengue is a self-limiting acute febrile illness followed by a phase of critical defervescence, in which patients may improve or progress to a severe form. Severe illness is characterized by hemodynamic disturbances, increased vascular permeability, hypovolemia, hypotension, and shock. Thrombocytopenia and platelet dysfunction are common in both cases and are related to the clinical outcome. Different mechanisms have been hypothesized to explain DENV-associated thrombocytopenia, including the suppression of bone marrow and the peripheral destruction of platelets. Studies have shown DENV-infected hematopoietic progenitors or bone marrow stromal cells. Moreover, anti-platelet antibodies would be involved in peripheral platelet destruction as platelets interact with endothelial cells, immune cells, and/or DENV. It is not yet clear whether platelets play a role in the viral spread. Here, we focus on the mechanisms of thrombocytopenia and platelet dysfunction in DENV infection. Because platelets participate in the inflammatory and immune response by promoting cytokine, chemokine, and inflammatory mediator secretion, their relevance as "immune-like effector cells" will be discussed. Finally, an implication for platelets in plasma leakage will be also regarded, as thrombocytopenia is associated with clinical outcome and higher mortality.
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260
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Cimmino G, Tarallo R, Nassa G, De Filippo MR, Giurato G, Ravo M, Rizzo F, Conte S, Pellegrino G, Cirillo P, Calabro P, Öhman T, Nyman TA, Weisz A, Golino P. Activating stimuli induce platelet microRNA modulation and proteome reorganisation. Thromb Haemost 2015; 114:96-108. [PMID: 25903651 DOI: 10.1160/th14-09-0726] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/27/2015] [Indexed: 11/05/2022]
Abstract
Platelets carry megakaryocyte-derived mRNAs whose translation efficiency before and during activation is not known, although this can greatly affect platelet functions, both under basal conditions and in response to physiological and pathological stimuli, such as those involved in acute coronary syndromes. Aim of the present study was to determine whether changes in microRNA (miRNA) expression occur in response to activating stimuli and whether this affects activity and composition of platelet transcriptome and proteome. Purified platelet-rich plasmas from healthy volunteers were collected and activated with ADP, collagen, or thrombin receptor activating peptide. Transcriptome analysis by RNA-Seq revealed that platelet transcriptome remained largely unaffected within the first 2 hours of stimulation. In contrast, quantitative proteomics showed that almost half of > 700 proteins quantified were modulated under the same conditions. Global miRNA analysis indicated that reorganisation of platelet proteome occurring during activation reflected changes in mature miRNA expression, which therefore, appears to be the main driver of the observed discrepancy between transcriptome and proteome changes. Platelet functions significantly affected by modulated miRNAs include, among others, the integrin/cytoskeletal, coagulation and inflammatory-immune response pathways. These results demonstrate a significant reprogramming of the platelet miRNome during activation, with consequent significant changes in platelet proteome and provide for the first time substantial evidence that fine-tuning of resident mRNA translation by miRNAs is a key event in platelet pathophysiology.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Alessandro Weisz
- Prof. Alessandro Weisz, MD, Laboratory of Molecular Medicine and Genomics, University of Salerno, via S. Allende, 1, 84081 Baronissi (SA), Italy, Tel.: +39 089 965043, Fax: +39 089 969657, E-mail:
| | - Paolo Golino
- Prof. Paolo Golino, MD, Department of Cardiothoracic and Respiratory Sciences, Second University of Naples, Via L. Bianchi, 1, 80131 Naples, Italy, Tel.: +39 0823 306395, Fax: +39 0823 232395, E-mail:
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261
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Binsker U, Kohler TP, Krauel K, Kohler S, Schwertz H, Hammerschmidt S. Pneumococcal Adhesins PavB and PspC Are Important for the Interplay with Human Thrombospondin-1. J Biol Chem 2015; 290:14542-55. [PMID: 25897078 DOI: 10.1074/jbc.m114.623876] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Indexed: 11/06/2022] Open
Abstract
The human matricellular glycoprotein thrombospondin-1 (hTSP-1) is released by activated platelets and mediates adhesion of Gram-positive bacteria to various host cells. In staphylococci, the adhesins extracellular adherence protein (Eap) and autolysin (Atl), both surface-exposed proteins containing repeating structures, were shown to be involved in the acquisition of hTSP-1 to the bacterial surface. The interaction partner(s) on the pneumococcal surface was hitherto unknown. Here, we demonstrate for the first time that pneumococcal adherence and virulence factor B (PavB) and pneumococcal surface protein C (PspC) are key players for the interaction of Streptococcus pneumoniae with matricellular hTSP-1. PavB and PspC are pneumococcal surface-exposed adhesins and virulence factors exhibiting repetitive sequences in their core structure. Heterologously expressed fragments of PavB and PspC containing repetitive structures exhibit hTSP-1 binding activity as shown by ELISA and surface plasmon resonance studies. Binding of hTSP-1 is charge-dependent and inhibited by heparin. Importantly, the deficiency in PavB and PspC reduces the recruitment of soluble hTSP-1 by pneumococci and decreases hTSP-1-mediated pneumococcal adherence to human epithelial cells. Platelet activation assays suggested that PavB and PspC are not involved in the activation of purified human platelets by pneumococci. In conclusion, this study indicates a pivotal role of PavB and PspC for pneumococcal recruitment of soluble hTSP-1 to the bacterial surface and binding of pneumococci to host cell-bound hTSP-1 during adhesion.
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Affiliation(s)
- Ulrike Binsker
- From the Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany and
| | - Thomas P Kohler
- From the Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany and
| | - Krystin Krauel
- Institute for Immunology and Transfusion Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Strasse, D-17489 Greifswald, Germany
| | - Sylvia Kohler
- From the Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany and
| | - Hansjörg Schwertz
- Institute for Immunology and Transfusion Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Strasse, D-17489 Greifswald, Germany
| | - Sven Hammerschmidt
- From the Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany and
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262
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Affiliation(s)
- L. H. Boudreau
- Centre de Recherche en Rhumatologie et Immunologie; Centre de Recherche du Centre Hospitalier Universitaire de Québec; Faculté de Médecine de l'Université Laval; Québec QC Canada
| | - G. Marcoux
- Centre de Recherche en Rhumatologie et Immunologie; Centre de Recherche du Centre Hospitalier Universitaire de Québec; Faculté de Médecine de l'Université Laval; Québec QC Canada
| | - E. Boilard
- Centre de Recherche en Rhumatologie et Immunologie; Centre de Recherche du Centre Hospitalier Universitaire de Québec; Faculté de Médecine de l'Université Laval; Québec QC Canada
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263
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Lunghi M, Galizi R, Magini A, Carruthers VB, Di Cristina M. Expression of the glycolytic enzymes enolase and lactate dehydrogenase during the early phase ofToxoplasmadifferentiation is regulated by an intron retention mechanism. Mol Microbiol 2015; 96:1159-75. [DOI: 10.1111/mmi.12999] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2015] [Indexed: 01/12/2023]
Affiliation(s)
- Matteo Lunghi
- Department of Chemistry, Biology and Biotechnology; University of Perugia; Perugia Italy
| | - Roberto Galizi
- Department of Experimental Medicine; University of Perugia; Perugia Italy
| | - Alessandro Magini
- Department of Chemistry, Biology and Biotechnology; University of Perugia; Perugia Italy
| | - Vern B. Carruthers
- Department of Microbiology and Immunology; University of Michigan Medical School; Ann Arbor MI USA
| | - Manlio Di Cristina
- Department of Chemistry, Biology and Biotechnology; University of Perugia; Perugia Italy
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264
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Ferdous F, Scott T. Bacterial and viral induction of chicken thrombocyte inflammatory responses. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2015; 49:225-230. [PMID: 25475960 DOI: 10.1016/j.dci.2014.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
Thrombocytes express Toll-like receptors (TLRs) that detect bacterial or viral pathogens to signal the release of cytokines and mediators. We examined inflammatory responses when thrombocytes were exposed to four TLR ligands. Treatment of thrombocytes with TLR ligands demonstrates differential effects on gene expression of interleukin (IL)-6. Among the TLR ligands examined, lipopolysaccharide stimulation led to the most significant up-regulation of the IL-6 gene and a significant amount of active IL-6 in thrombocyte culture media. Lipoteichoic acid stimulation led to only marginal up-regulation of IL-6 gene expression. Although gene expression of inducible nitric oxide synthase (iNOS) did not increase due to different ligand exposure, a low level constitutive expression of iNOS was observed in all cases. Only thrombocytes treated with polyinosinic-polycytidylic acid and thymidine homopolymer phosphorothioate oligodeoxynucleotides induced rapid, significant production of nitric oxide. We also observed that thrombocytes are able to respond faster upon TLR ligand exposure compared to MQ.NCSU macrophages.
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Affiliation(s)
- F Ferdous
- Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634-0311, USA
| | - T Scott
- Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634-0311, USA.
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265
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Abstract
Bacteria that enter the bloodstream will encounter components of the cellular and soluble immune response. Platelets contribute to this response and have emerged as an important target for bacterial pathogens. Bacteria produce diverse extracellular proteins and toxins that have been reported to modulate platelet function. These interactions can result in complete or incomplete platelet activation or inhibition of platelet activation, depending on the bacteria and bacterial product. The nature of the platelet response may be highly relevant to disease pathogenesis.
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Affiliation(s)
- Oonagh Shannon
- Division of Infection Medicine, Department of Clinical Sciences, Lund University , Lund , Sweden
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266
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Abstract
Although platelets are traditionally recognized for their central role in hemostasis, many lines of research clearly demonstrate these rather ubiquitous blood components are potent immune modulators and effectors. Platelets have been shown to directly recognize, sequester and kill pathogens, to activated and recruit leukocytes to sites of infection and inflammation, and to modulate leukocyte behavior, enhancing their ability to phagocytose and kill pathogens and inducing unique effector functions, such as the production of Neutrophil Extracellular Traps (NETs). This multifaceted response to infection and inflammation is due, in part, to the huge array of soluble mediators and cell surface molecules expressed by platelets. From their earliest origins as primordial hemocytes in invertebrates to their current form as megakaryocyte-derived cytoplasts, platelets have evolved to be one of the key regulators of host intravascular immunity and inflammation. In this review, we present the diverse roles platelets play in immunity and inflammation associated with autoimmune diseases and infection. Additionally, we highlight recent advances in our understanding of platelet behavior made possible through the use of advanced imaging techniques that allow us to visualize platelets and their interactions, in real-time, within the intact blood vessels of a living host.
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Affiliation(s)
- Craig N Jenne
- Department of Microbiology, Immunology and Infectious Diseases and
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267
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Dewitte A, Tanga A, Villeneuve J, Lepreux S, Ouattara A, Desmoulière A, Combe C, Ripoche J. New frontiers for platelet CD154. Exp Hematol Oncol 2015; 4:6. [PMID: 25763299 PMCID: PMC4355125 DOI: 10.1186/s40164-015-0001-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 02/03/2015] [Indexed: 02/07/2023] Open
Abstract
The role of platelets extends beyond hemostasis. The pivotal role of platelets in inflammation has shed new light on the natural history of conditions associated with acute or chronic inflammation. Beyond the preservation of vascular integrity, platelets are essential to tissue homeostasis and platelet-derived products are already used in the clinics. Unanticipated was the role of platelets in the adaptative immune response, allowing a renewed conceptual approach of auto-immune diseases. Platelets are also important players in cancer growth and dissemination. Platelets fulfill most of their functions through the expression of still incompletely characterized membrane-bound or soluble mediators. Among them, CD154 holds a peculiar position, as platelets represent a major source of CD154 and as CD154 contributes to most of these new platelet attributes. Here, we provide an overview of some of the new frontiers that the study of platelet CD154 is opening, in inflammation, tissue homeostasis, immune response, hematopoiesis and cancer.
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Affiliation(s)
- Antoine Dewitte
- INSERM U1026, and Université de Bordeaux, F-33000 Bordeaux, France ; Service d'Anesthésie-Réanimation II, CHU de Bordeaux, F-33600 Pessac, France
| | - Annabelle Tanga
- INSERM U1026, and Université de Bordeaux, F-33000 Bordeaux, France
| | - Julien Villeneuve
- Cell and Developmental Biology Programme, Centre for Genomic Regulation, 08003 Barcelona, Spain ; Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3200 USA
| | | | - Alexandre Ouattara
- Service d'Anesthésie-Réanimation II, CHU de Bordeaux, F-33600 Pessac, France
| | | | - Christian Combe
- INSERM U1026, and Université de Bordeaux, F-33000 Bordeaux, France ; Service de Néphrologie Transplantation Dialyse, CHU de Bordeaux, F-33076 Bordeaux, France
| | - Jean Ripoche
- INSERM U1026, and Université de Bordeaux, F-33000 Bordeaux, France
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268
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Boutz PL, Bhutkar A, Sharp PA. Detained introns are a novel, widespread class of post-transcriptionally spliced introns. Genes Dev 2015; 29:63-80. [PMID: 25561496 PMCID: PMC4281565 DOI: 10.1101/gad.247361.114] [Citation(s) in RCA: 275] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Deep sequencing of embryonic stem cell RNA revealed many specific internal introns that are significantly more abundant than the other introns within polyadenylated transcripts. Boutz et al. identified thousands of these “detained” introns (DIs) in human and mouse cell lines as well as the adult mouse liver. Drug inhibition of Clk, a stress-responsive kinase, triggered rapid splicing changes for a specific subset of DIs, altering transcript pools of >300 genes. Srsf4 regulates the splicing of some DIs, particularly in genes encoding RNA processing and splicing factors. Deep sequencing of embryonic stem cell RNA revealed many specific internal introns that are significantly more abundant than the other introns within polyadenylated transcripts; we classified these as “detained” introns (DIs). We identified thousands of DIs, many of which are evolutionarily conserved, in human and mouse cell lines as well as the adult mouse liver. DIs can have half-lives of over an hour yet remain in the nucleus and are not subject to nonsense-mediated decay (NMD). Drug inhibition of Clk, a stress-responsive kinase, triggered rapid splicing changes for a specific subset of DIs; half showed increased splicing, and half showed increased intron detention, altering transcript pools of >300 genes. Srsf4, which undergoes a dramatic phosphorylation shift in response to Clk kinase inhibition, regulates the splicing of some DIs, particularly in genes encoding RNA processing and splicing factors. The splicing of some DIs—including those in Mdm4, a negative regulator of p53—was also altered following DNA damage. After 4 h of Clk inhibition, the expression of >400 genes changed significantly, and almost one-third of these are p53 transcriptional targets. These data suggest a widespread mechanism by which the rate of splicing of DIs contributes to the level of gene expression.
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Affiliation(s)
- Paul L Boutz
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Arjun Bhutkar
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Phillip A Sharp
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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269
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Inflammasome in platelets: allying coagulation and inflammation in infectious and sterile diseases? Mediators Inflamm 2015; 2015:435783. [PMID: 25814789 PMCID: PMC4357129 DOI: 10.1155/2015/435783] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 01/24/2015] [Accepted: 01/26/2015] [Indexed: 12/27/2022] Open
Abstract
Platelets are crucial effector cells in hemostasis. In addition, platelets are increasingly recognized as major inflammatory cells with key roles in innate and adaptive immune responses. Activated platelets have key thromboinflammatory activities linking coagulation to inflammatory response in a variety of coagulation disorders and vasculopathies. Recently identified inflammatory activities of platelets include the synthesis of IL-1β from spliced pre-RNA, as well as the presence and assembly of inflammasome which intermediate IL-1β secretion. Here we review the mechanisms by which platelets activate translation machinery and inflammasome assembly to synthesize and release IL-1β. The contributions of these processes to protective and pathogenic responses during infectious and inflammatory diseases are discussed.
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270
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Mammalian introns: when the junk generates molecular diversity. Int J Mol Sci 2015; 16:4429-52. [PMID: 25710723 PMCID: PMC4394429 DOI: 10.3390/ijms16034429] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 02/06/2015] [Accepted: 02/11/2015] [Indexed: 01/14/2023] Open
Abstract
Introns represent almost half of the human genome, yet their vast majority is eliminated from eukaryotic transcripts through RNA splicing. Nevertheless, they feature key elements and functions that deserve further interest. At the level of DNA, introns are genomic segments that can shelter independent transcription units for coding and non-coding RNAs which transcription may interfere with that of the host gene, and regulatory elements that can influence gene expression and splicing itself. From the RNA perspective, some introns can be subjected to alternative splicing. Intron retention appear to provide some plasticity to the nature of the protein produced, its distribution in a given cell type and timing of its translation. Intron retention may also serve as a switch to produce coding or non-coding RNAs from the same transcription unit. Conversely, splicing of introns has been directly implicated in the production of small regulatory RNAs. Hence, splicing of introns also appears to provide plasticity to the type of RNA produced from a genetic locus (coding, non-coding, short or long). We addressed these aspects to add to our understanding of mechanisms that control the fate of introns and could be instrumental in regulating genomic output and hence cell fate.
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271
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Garraud O, Cognasse F. Are Platelets Cells? And if Yes, are They Immune Cells? Front Immunol 2015; 6:70. [PMID: 25750642 PMCID: PMC4335469 DOI: 10.3389/fimmu.2015.00070] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 02/03/2015] [Indexed: 02/06/2023] Open
Abstract
Small fragments circulating in the blood were formally identified by the end of the nineteenth century, and it was suggested that they assisted coagulation via interactions with vessel endothelia. Wright, at the beginning of the twentieth century, identified their bone-marrow origin. For long, platelets have been considered sticky assistants of hemostasis and pollutants of blood or tissue samples; they were just cell fragments. As such, however, they were acknowledged as immunizing (to specific HPA and HLA markers): the platelet’s dark face. The enlightened face showed that besides hemostasis, platelets contained factors involved in healing. As early as 1930s, platelets entered the arsenal of medicines were transfused, and were soon manipulated to become a kind of glue to repair damaged tissues. Some gladly categorized platelets as cells but they were certainly not fully licensed as such for cell physiologists. Actually, platelets possess almost every characteristic of cells, apart from being capable of organizing their genes: they have neither a nucleus nor genes. This view prevailed until it became evident that platelets play a role in homeostasis and interact with cells other than with vascular endothelial cells; then began the era of physiological and also pathological inflammation. Platelets have now entered the field of immunity as inflammatory cells. Does assistance to immune cells itself suffice to license a cell as an “immune cell”? Platelets prove capable of sensing different types of signals and organizing an appropriate response. Many cells can do that. However, platelets can use a complete signalosome (apart from the last transcription step, though it is likely that this step can be circumvented by retrotranscribing RNA messages). The question has also arisen as to whether platelets can present antigen via their abundantly expressed MHC class I molecules. In combination, these properties argue in favor of allowing platelets the title of immune cells.
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Affiliation(s)
- Olivier Garraud
- Institut National de la Transfusion Sanguine , Paris , France ; EA3064, Université de Lyon , Saint-Etienne , France
| | - Fabrice Cognasse
- EA3064, Université de Lyon , Saint-Etienne , France ; Etablissement Français du Sang Auvergne-Loire , Saint-Etienne , France
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272
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Lannan KL, Sahler J, Kim N, Spinelli SL, Maggirwar SB, Garraud O, Cognasse F, Blumberg N, Phipps RP. Breaking the mold: transcription factors in the anucleate platelet and platelet-derived microparticles. Front Immunol 2015; 6:48. [PMID: 25762994 PMCID: PMC4327621 DOI: 10.3389/fimmu.2015.00048] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 01/26/2015] [Indexed: 01/15/2023] Open
Abstract
Platelets are small anucleate blood cells derived from megakaryocytes. In addition to their pivotal roles in hemostasis, platelets are the smallest, yet most abundant, immune cells and regulate inflammation, immunity, and disease progression. Although platelets lack DNA, and thus no functional transcriptional activities, they are nonetheless rich sources of RNAs, possess an intact spliceosome, and are thus capable of synthesizing proteins. Previously, it was thought that platelet RNAs and translational machinery were remnants from the megakaryocyte. We now know that the initial description of platelets as "cellular fragments" is an antiquated notion, as mounting evidence suggests otherwise. Therefore, it is reasonable to hypothesize that platelet transcription factors are not vestigial remnants from megakaryocytes, but have important, if only partly understood functions. Proteins play multiple cellular roles to minimize energy expenditure for maximum cellular function; thus, the same can be expected for transcription factors. In fact, numerous transcription factors have non-genomic roles, both in platelets and in nucleated cells. Our lab and others have discovered the presence and non-genomic roles of transcription factors in platelets, such as the nuclear factor kappa β (NFκB) family of proteins and peroxisome proliferator-activated receptor gamma (PPARγ). In addition to numerous roles in regulating platelet activation, functional transcription factors can be transferred to vascular and immune cells through platelet microparticles. This method of transcellular delivery of key immune molecules may be a vital mechanism by which platelet transcription factors regulate inflammation and immunity. At the very least, platelets are an ideal model cell to dissect out the non-genomic roles of transcription factors in nucleated cells. There is abundant evidence to suggest that transcription factors in platelets play key roles in regulating inflammatory and hemostatic functions.
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Affiliation(s)
- Katie L Lannan
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA
| | - Julie Sahler
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA ; Department of Biological and Environmental Engineering, Cornell University , Ithaca, NY , USA
| | - Nina Kim
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA
| | - Sherry L Spinelli
- Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA
| | - Sanjay B Maggirwar
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA
| | - Olivier Garraud
- Faculté de Médecine, Université de Lyon , Saint-Etienne , France
| | - Fabrice Cognasse
- Faculté de Médecine, Université de Lyon , Saint-Etienne , France ; Etablissement Français du Sang Auvergne-Loire , Saint-Etienne , France
| | - Neil Blumberg
- Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA
| | - Richard P Phipps
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA ; Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA ; Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry , Rochester, NY , USA
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273
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Stolla M, Refaai MA, Heal JM, Spinelli SL, Garraud O, Phipps RP, Blumberg N. Platelet transfusion - the new immunology of an old therapy. Front Immunol 2015; 6:28. [PMID: 25699046 PMCID: PMC4313719 DOI: 10.3389/fimmu.2015.00028] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/14/2015] [Indexed: 01/14/2023] Open
Abstract
Platelet transfusion has been a vital therapeutic approach in patients with hematologic malignancies for close to half a century. Randomized trials show that prophylactic platelet transfusions mitigate bleeding in patients with acute myeloid leukemia. However, even with prophylactic transfusions, as many as 75% of patients, experience hemorrhage. While platelet transfusion efficacy is modest, questions and concerns have arisen about the risks of platelet transfusion therapy. The acknowledged serious risks of platelet transfusion include viral transmission, bacterial sepsis, and acute lung injury. Less serious adverse effects include allergic and non-hemolytic febrile reactions. Rare hemolytic reactions have occurred due to a common policy of transfusing without regard to ABO type. In the last decade or so, new concerns have arisen; platelet-derived lipids are implicated in transfusion-related acute lung injury after transfusion. With the recognition that platelets are immune cells came the discoveries that supernatant IL-6, IL-27 sCD40L, and OX40L are closely linked to febrile reactions and sCD40L with acute lung injury. Platelet transfusions are pro-inflammatory, and may be pro-thrombotic. Anti-A and anti-B can bind to incompatible recipient or donor platelets and soluble antigens, impair hemostasis and thus increase bleeding. Finally, stored platelet supernatants contain biological mediators such as VEGF and TGF-β1 that may compromise the host versus tumor response. This is particularly of concern in patients receiving many platelet transfusions, as for acute leukemia. New evidence suggests that removing stored supernatant will improve clinical outcomes. This new view of platelets as pro-inflammatory and immunomodulatory agents suggests that innovative approaches to improving platelet storage and pre-transfusion manipulations to reduce toxicity could substantially improve the efficacy and safety of this long-employed therapy.
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Affiliation(s)
- Moritz Stolla
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA
| | - Majed A Refaai
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA
| | - Joanna M Heal
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA
| | - Sherry L Spinelli
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA
| | - Olivier Garraud
- Etablissement Francais du Sang Auvergne-Loire, Universite de Lyon , Saint-Etienne , France
| | - Richard P Phipps
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA ; Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA ; Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA ; Department of Medicine, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA
| | - Neil Blumberg
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester Medical Center , Rochester, NY , USA
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274
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Patzelt J, Mueller K, Breuning S, Karathanos A, Schleicher R, Seizer P, Gawaz M, Langer H, Geisler T. Expression of anaphylatoxin receptors on platelets in patients with coronary heart disease. Atherosclerosis 2015; 238:289-95. [DOI: 10.1016/j.atherosclerosis.2014.12.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 10/15/2014] [Accepted: 12/04/2014] [Indexed: 01/06/2023]
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275
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Chronic hepatitis B: role of anti-platelet therapy in inflammation control. Cell Mol Immunol 2015; 12:264-8. [PMID: 25578311 DOI: 10.1038/cmi.2014.124] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/30/2014] [Accepted: 11/19/2014] [Indexed: 01/04/2023] Open
Abstract
Platelets play a known role in the maintenance of vascular homeostasis, but these cells are emerging as important cellular mediators of acute and chronic inflammatory diseases. Platelets are key elements in the pathogenesis of acute and chronic liver disease associated with hepatitis B virus (HBV) infection by promoting the accumulation of virus-specific CD8(+) T cells and nonspecific inflammatory cells into the liver parenchyma. This review discusses major platelet functions in immune and inflammatory responses, with an emphasis on recent pre-clinical studies that suggest that the inhibition of platelet activation pathways represent an alternative therapeutic strategy with potential use in the reduction of virus-specific T cell-mediated chronic inflammation, liver fibrosis and hepatocellular carcinoma in patients who are chronically infected with HBV.
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276
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Lang F, Gawaz M, Borst O. The serum- & glucocorticoid-inducible kinase in the regulation of platelet function. Acta Physiol (Oxf) 2015; 213:181-90. [PMID: 24947805 DOI: 10.1111/apha.12334] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 06/02/2014] [Accepted: 06/15/2014] [Indexed: 12/23/2022]
Abstract
The serum- and glucocorticoid-inducible kinase 1 (SGK1) is expressed in megakaryocytes and circulating platelets. In megakaryocytes, SGK1 activates transcription factor nuclear factor kappa-B (NF-κB), which in turn stimulates expression of Orai1, a Ca(2+) channel protein accomplishing store-operated Ca(2+) enrty (SOCE). SGK1 enhances SOCE and several Ca(2+) -sensitive platelet functions, including degranulation, integrin αII b β3 activation, phosphatidylserine exposure, aggregation and thrombus formation. As shown in other cell types, stimulators of SGK1 expression include ischaemia, oxidative stress, hyperglycaemia, advanced glycation end products (AGEs) and a variety of hormones such as glucocorticoids, mineralocorticoids, transforming growth factor beta (TGFβ), interleukin 6 (IL-6), platelet-derived growth factor (PDGF), thrombin and endothelin. Thus, SGK1-sensitive Ca(2+) signalling may contribute to altered platelet function in several clinical conditions including inflammation, metabolic syndrome, diabetes mellitus and chronic renal failure. Nevertheless, further studies are needed defining the contribution of altered SGK1 expression and activity to physiology and pathophysiology of platelets.
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Affiliation(s)
- F. Lang
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - M. Gawaz
- Department of Cardiology & Cardiovascular Medicine; University of Tübingen; Tübingen Germany
| | - O. Borst
- Department of Physiology; University of Tübingen; Tübingen Germany
- Department of Cardiology & Cardiovascular Medicine; University of Tübingen; Tübingen Germany
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277
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Ferdous F, Scott T. A comparative examination of thrombocyte/platelet immunity. Immunol Lett 2015; 163:32-9. [DOI: 10.1016/j.imlet.2014.11.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 10/30/2014] [Accepted: 11/12/2014] [Indexed: 10/24/2022]
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278
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Rondina MT, Garraud O. Emerging evidence for platelets as immune and inflammatory effector cells. Front Immunol 2014; 5:653. [PMID: 25566264 PMCID: PMC4270189 DOI: 10.3389/fimmu.2014.00653] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/06/2014] [Indexed: 12/20/2022] Open
Abstract
While traditionally recognized for their roles in hemostatic pathways, emerging evidence demonstrates that platelets have previously unrecognized, dynamic roles that span the immune continuum. These newly recognized platelet functions, including the secretion of immune mediators, interactions with endothelial cells, monocytes, and neutrophils, toll-like receptor (TLR) mediated responses, and induction of neutrophil extracellular trap formation, bridge thrombotic and inflammatory pathways and contribute to host defense mechanisms against invading pathogens. In this focused review, we highlight several of these emerging aspects of platelet biology and their implications in clinical infectious syndromes.
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Affiliation(s)
- Matthew T Rondina
- Division of General Internal Medicine, University of Utah , Salt Lake City, UT , USA ; Program in Molecular Medicine, University of Utah School of Medicine , Salt Lake City, UT , USA ; Department of Internal Medicine, George E. Wahlen Department of Veterans Affairs Medical Center , Salt Lake City, UT , USA
| | - Olivier Garraud
- Faculty of Medicine of Saint-Etienne, University of Lyon , Lyon , France ; French Blood Establishment, Auvergne-Loire , Saint-Etienne , France
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279
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Gabbasov Z, Sabo J, Petrovic D, Martell-Claros N, Zagatina A, Mrdovic I, Ciccocioppo R, Cangemi GC, Klimas J, Kruzliak P. Impact of platelet phenotype on myocardial infarction. Biomarkers 2014; 20:17-25. [PMID: 25510672 DOI: 10.3109/1354750x.2014.993707] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In acute myocardial infarction patients the injured vascular wall triggers thrombus formation in the damage site. Fibrin fibers and blood cellular elements are the major components of thrombus formed in acute occlusion of coronary arteries. It has been established that the initial thrombus is primarily composed of activated platelets rapidly stabilized by fibrin fibers. This review highlights the role of platelet membrane phenotype in pathophysiology of myocardial infarction. Here, we regard platelet phenotype as quantitative and qualitative parameters of the plasma membrane outer surface, which are crucial for platelet participation in blood coagulation, development of local inflammation and tissue repair.
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Affiliation(s)
- Zufar Gabbasov
- Institute of Experimental Cardiology, Cardiology Research Center , Moscow , Russia
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280
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Weyrich AS. Platelets: more than a sack of glue. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2014; 2014:400-403. [PMID: 25696885 DOI: 10.1182/asheducation-2014.1.400] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Platelets are primary effector cells in hemostasis. Emerging evidence over the last decade, however, demonstrates that platelets also have critical roles in immunity and inflammation. These nontraditional functions of platelets influence the development, progression, and evolution of numerous diseases, including arthritis, cancer, cardiovascular disease, and infectious syndromes. This chapters reviews recently discovered attributes of platelets that contribute to human disease, paying particular attention to the inflammatory activities of this anucleate cytoplast.
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Affiliation(s)
- Andrew S Weyrich
- Molecular Medicine Program and the Department of Internal Medicine, University of Utah, Salt Lake City, UT
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281
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Hinckley J, Di Paola J. Genetic basis of congenital platelet disorders. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2014; 2014:337-342. [PMID: 25696876 DOI: 10.1182/asheducation-2014.1.337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Over the past 4 decades, a better understanding of the genetic origins of inherited platelet disorders has illuminated avenues of investigation in megakaryopoiesis and has identified targets of pharmacologic intervention. Many of these discoveries have been translated into clinical medicine. The success of inherited platelet disorder research is underpinned by broader advances in methodology through the biochemical and molecular revolution of the 20(th) and 21(st) centuries, respectively. Recently, modern genomics techniques have affected platelet and platelet disorders research, allowing for the discovery of several genes involved in platelet production and function and for a deeper understanding of the RNA and miRNA networks that govern platelet function. In this short review, we focus on recent developments in the genetic elucidation of several disorders of platelet number and in the molecular architecture that determines the "genetic makeup" of a platelet in health and disease.
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Affiliation(s)
- Jesse Hinckley
- Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO
| | - Jorge Di Paola
- Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO
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282
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The signaling role of CD40 ligand in platelet biology and in platelet component transfusion. Int J Mol Sci 2014; 15:22342-64. [PMID: 25479079 PMCID: PMC4284712 DOI: 10.3390/ijms151222342] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 11/25/2014] [Accepted: 11/27/2014] [Indexed: 12/13/2022] Open
Abstract
The CD40 ligand (CD40L) is a transmembrane molecule of crucial interest in cell signaling in innate and adaptive immunity. It is expressed by a variety of cells, but mainly by activated T-lymphocytes and platelets. CD40L may be cleaved into a soluble form (sCD40L) that has a cytokine-like activity. Both forms bind to several receptors, including CD40. This interaction is necessary for the antigen specific immune response. Furthermore, CD40L and sCD40L are involved in inflammation and a panoply of immune related and vascular pathologies. Soluble CD40L is primarily produced by platelets after activation, degranulation and cleavage, which may present a problem for transfusion. Soluble CD40L is involved in adverse transfusion events including transfusion related acute lung injury (TRALI). Although platelet storage designed for transfusion occurs in sterile conditions, platelets are activated and release sCD40L without known agonists. Recently, proteomic studies identified signaling pathways activated in platelet concentrates. Soluble CD40L is a good candidate for platelet activation in an auto-amplification loop. In this review, we describe the immunomodulatory role of CD40L in physiological and pathological conditions. We will focus on the main signaling pathways activated by CD40L after binding to its different receptors.
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283
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Heyn P, Kalinka AT, Tomancak P, Neugebauer KM. Introns and gene expression: cellular constraints, transcriptional regulation, and evolutionary consequences. Bioessays 2014; 37:148-54. [PMID: 25400101 PMCID: PMC4654234 DOI: 10.1002/bies.201400138] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A gene's “expression profile” denotes the number of transcripts present relative to all other transcripts. The overall rate of transcript production is determined by transcription and RNA processing rates. While the speed of elongating RNA polymerase II has been characterized for many different genes and organisms, gene-architectural features – primarily the number and length of exons and introns – have recently emerged as important regulatory players. Several new studies indicate that rapidly cycling cells constrain gene-architecture toward short genes with a few introns, allowing efficient expression during short cell cycles. In contrast, longer genes with long introns exhibit delayed expression, which can serve as timing mechanisms for patterning processes. These findings indicate that cell cycle constraints drive the evolution of gene-architecture and shape the transcriptome of a given cell type. Furthermore, a tendency for short genes to be evolutionarily young hints at links between cellular constraints and the evolution of animal ontogeny.
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Affiliation(s)
- Patricia Heyn
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
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284
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Ibrahim H, Schutt RC, Hannawi B, DeLao T, Barker CM, Kleiman NS. Association of immature platelets with adverse cardiovascular outcomes. J Am Coll Cardiol 2014; 64:2122-9. [PMID: 25457402 DOI: 10.1016/j.jacc.2014.06.1210] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/11/2014] [Accepted: 06/30/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND Immature platelets are less responsive to the effects of antiplatelet drugs and contain messenger ribonucleic acid that is translationally active. They can be measured easily using an automated hematoanalyzer and reported as part of the complete blood count. OBJECTIVES The purpose of this study was to determine the prognostic significance of elevated immature platelet count (IPC) in patients with coronary artery disease (CAD). METHODS In this prospective cohort study in patients with CAD, patients underwent IPC measurement and were then followed up for the composite endpoint of major adverse cardiovascular events (MACE), defined as a composite of all-cause mortality, myocardial infarction, unplanned revascularization, or hospitalization for angina. For the purposes of analysis, patients were stratified into tertiles of IPC. RESULTS Eighty-nine patients were followed up for a median of 31 months. Stratification to the high IPC tertile was associated with higher rates of MACE compared with the intermediate and low tertiles (60% vs. 24% vs. 16%, respectively; p < 0.001). Time-dependent receiver-operating characteristic analysis revealed that an IPC level ≥7,632 platelets/μl was 70.7% sensitive and 82.1% specific for MACE. After adjustment for age, admission diagnosis, index revascularization, heart failure, smoking, hematocrit, and baseline platelet count, patients with an IPC level ≥7,632 platelets/μl were more likely to experience a MACE (hazard ratio: 4.65; 95% confidence interval: 1.78 to 12.16; p < 0.002). CONCLUSIONS IPC is a novel biomarker for MACE risk stratification in patients with CAD. Future studies should focus on the utilization of this marker for individualized antiplatelet therapy.
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Affiliation(s)
- Homam Ibrahim
- Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas; Weill-Cornell Medical College, New York, New York
| | - Robert C Schutt
- Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas; Weill-Cornell Medical College, New York, New York
| | - Bashar Hannawi
- Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas; Weill-Cornell Medical College, New York, New York
| | - Timothy DeLao
- Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas
| | - Colin M Barker
- Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas; Weill-Cornell Medical College, New York, New York
| | - Neal S Kleiman
- Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas; Weill-Cornell Medical College, New York, New York.
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285
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Herter JM, Rossaint J, Zarbock A. Platelets in inflammation and immunity. J Thromb Haemost 2014; 12:1764-75. [PMID: 25224706 DOI: 10.1111/jth.12730] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 09/01/2014] [Indexed: 02/06/2023]
Abstract
The paradigm of platelets as mere mediators of hemostasis has long since been replaced by a dual role: hemostasis and inflammation. Now recognized as key players in innate and adaptive immune responses, platelets have the capacity to interact with almost all known immune cells. These platelet-immune cell interactions represent a hallmark of immunity, as they can potently enhance immune cell functions and, in some cases, even constitute a prerequisite for host defense mechanisms such as NETosis. In addition, recent studies have revealed a new role for platelets in immunity: They are ubiquitous sentinels and rapid first-line immune responders, as platelet-pathogen interactions within the vasculature appear to precede all other host defense mechanisms. Here, we discuss recent advances in our understanding of platelets as inflammatory cells, and provide an exemplary review of their role in acute inflammation.
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Affiliation(s)
- J M Herter
- Center for Excellence in Vascular Biology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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286
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Diner I, Hales CM, Bishof I, Rabenold L, Duong DM, Yi H, Laur O, Gearing M, Troncoso J, Thambisetty M, Lah JJ, Levey AI, Seyfried NT. Aggregation properties of the small nuclear ribonucleoprotein U1-70K in Alzheimer disease. J Biol Chem 2014; 289:35296-313. [PMID: 25355317 DOI: 10.1074/jbc.m114.562959] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent evidence indicates that U1-70K and other U1 small nuclear ribonucleoproteins are Sarkosyl-insoluble and associate with Tau neurofibrillary tangles selectively in Alzheimer disease (AD). Currently, the mechanisms underlying the conversion of soluble nuclear U1 small nuclear ribonucleoproteins into insoluble cytoplasmic aggregates remain elusive. Based on the biochemical and subcellular distribution properties of U1-70K in AD, we hypothesized that aggregated U1-70K itself or other biopolymers (e.g. proteins or nucleic acids) interact with and sequester natively folded soluble U1-70K into insoluble aggregates. Here, we demonstrate that total homogenates from AD brain induce soluble U1-70K from control brain or recombinant U1-70K to become Sarkosyl-insoluble. This effect was not dependent on RNA and did not correlate with detergent-insoluble Tau levels as AD homogenates with reduced levels of these components were still capable of inducing U1-70K aggregation. In contrast, proteinase K-treated AD homogenates and Sarkosyl-soluble AD fractions were unable to induce U1-70K aggregation, indicating that aggregated proteins in AD brain are responsible for inducing soluble U1-70K aggregation. It was determined that the C terminus of U1-70K, which harbors two disordered low complexity (LC) domains, is necessary for U1-70K aggregation. Moreover, both LC1 and LC2 domains were sufficient for aggregation. Finally, protein cross-linking and mass spectrometry studies demonstrated that a U1-70K fragment harboring the LC1 domain directly interacts with aggregated U1-70K in AD brain. Our results support a hypothesis that aberrant forms of U1-70K in AD can directly sequester soluble forms of U1-70K into insoluble aggregates.
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Affiliation(s)
- Ian Diner
- From the Departments of Biochemistry and the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Chadwick M Hales
- the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322 Neurology
| | - Isaac Bishof
- From the Departments of Biochemistry and the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Lake Rabenold
- From the Departments of Biochemistry and the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Duc M Duong
- From the Departments of Biochemistry and the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Hong Yi
- Emory University School of Medicine, Atlanta, Georgia 30322 Robert P. Apkarian Integrated Electron Microscopy Core
| | - Oskar Laur
- Emory University School of Medicine, Atlanta, Georgia 30322 Division of Microbiology, and Yerkes Research Center, Emory University, Atlanta, Georgia 30322
| | - Marla Gearing
- the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322 the Departments of Experimental Pathology and
| | - Juan Troncoso
- Pathology and Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205
| | | | - James J Lah
- the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322 Neurology
| | - Allan I Levey
- the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322 Neurology
| | - Nicholas T Seyfried
- From the Departments of Biochemistry and the Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322 Neurology,
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287
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Abstract
Coherent splicing networks arise from many discrete splicing decisions regulated in unison. Here, we examine the properties of robust, context-specific splicing networks. We propose that a subset of key splicing regulators, or "master splicing factors," respond to environmental cues to establish and maintain tissue transcriptomes during development.
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Affiliation(s)
- Mohini Jangi
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Phillip A Sharp
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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288
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Abstract
Atherosclerosis reduces platelet survival and thereby increases the percentage of younger platelets in the circulation assuming steady-state thrombocytopoiesis. We hypothesized that younger platelets have an increased propensity for arterial thrombus participation compared to older counterparts. Platelet-rich thrombi were generated by perfusing human heparinized whole blood from normal donors over arterial cross-sections under shear conditions (3,350 s(-1)) corresponding to significant coronary artery stenosis using a perfusion chamber. Harvested thrombi were disaggregated, stained with thiazole orange, anti-integrin β3, glycoprotein (GP) Ibα, GP IX and P-selectin, and compared to paired whole blood samples from the same donor by flow cytometry. Thiazole orange staining intensity provides a measure of platelet m-RNA content and age. Thiazole orange staining intensity (MN ± SEM) of platelets harvested from thrombi (62 ± 13) was twofold greater compared to paired intra-individual whole blood samples (31 ± 1). Integrin β3 receptor density was also greater for thrombus platelets (12.0 ± 1.0) compared to whole blood platelets (7.0 ± 0.6; p < 0.0001). GPs Ibα and IX were reduced from thrombus platelets possibly reflecting shedding. Younger "reticulated" platelets appear to have a greater propensity for thrombus participation under shear conditions of coronary artery stenosis compared to older counterparts. This predisposition may be explained by an increased receptor density of integrin β3 in younger platelets. By this mechanism, the atherosclerotic process may enhance the individual propensity for arterial thrombosis.
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289
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Mannhalter C. Infections and the role of plasma proteins and platelets. Thromb Haemost 2014; 112:630-1. [PMID: 25208736 DOI: 10.1160/th14-09-0721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/02/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Christine Mannhalter
- Prof. Christine Mannhalter, Department of Laboratory Medicine, Medical University Vienna, Vienna, Austria, E-mail:
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290
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Duerschmied D, Bode C, Ahrens I. Immune functions of platelets. Thromb Haemost 2014; 112:678-91. [PMID: 25209670 DOI: 10.1160/th14-02-0146] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 09/03/2014] [Indexed: 01/12/2023]
Abstract
This review collects evidence about immune and inflammatory functions of platelets from a clinician's point of view. A focus on clinically relevant immune functions aims at stimulating further research, because the complexity of platelet immunity is incompletely understood and not yet translated into patient care. Platelets promote chronic inflammatory reactions (e.g. in atherosclerosis), modulate acute inflammatory disorders such as sepsis and other infections (participating in the host defense against pathogens), and contribute to exacerbations of autoimmune conditions (like asthma or arthritis). It would hence be obsolete to restrict a description of platelet functions to thrombosis and haemostasis--platelets clearly are the most abundant cells with immune functions in the circulation.
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Affiliation(s)
- Daniel Duerschmied
- Daniel Duerschmied, MD, Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany, Tel.: +49 761 207 34410, Fax: +49 761 270 37855, E-mail:
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291
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Talhouarne GJS, Gall JG. Lariat intronic RNAs in the cytoplasm of Xenopus tropicalis oocytes. RNA (NEW YORK, N.Y.) 2014; 20:1476-87. [PMID: 25051970 PMCID: PMC4138330 DOI: 10.1261/rna.045781.114] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We previously demonstrated that the oocyte nucleus (germinal vesicle or GV) of Xenopus tropicalis contains a population of stable RNA molecules derived from the introns of most expressed genes. Here we show that similar stable intronic sequence (sis) RNAs occur in the oocyte cytoplasm. About 9000 cytoplasmic sisRNAs have been identified, all of which are resistant to the exonuclease RNase R. About half have been confirmed as lariat molecules and the rest are presumed to be lariats, whereas nuclear sisRNAs are a mixture of lariat and linear molecules. Cytoplasmic sisRNAs are more abundant on a molar basis than nuclear sisRNAs and are derived from short introns, mostly under 1 kb in length. Both nuclear and cytoplasmic sisRNAs are transmitted intact to the egg at GV breakdown and persist until at least the blastula stage of embryogenesis, when zygotic transcription begins. We compared cytoplasmic sisRNAs derived from orthologous genes of X. tropicalis and X. laevis, and found that the specific introns from which sisRNAs are derived are not conserved. The existence of sisRNAs in the cytoplasm of the oocyte, their transmission to the fertilized egg, and their persistence during early embryogenesis suggest that they might play a regulatory role in mRNA translation.
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Affiliation(s)
- Gaëlle J S Talhouarne
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA Department of Biology, Mudd Hall, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Joseph G Gall
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA Department of Biology, Mudd Hall, Johns Hopkins University, Baltimore, Maryland 21218, USA
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292
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Kuo HH, Fan R, Dvorina N, Chiesa-Vottero A, Baldwin WM. Platelets in early antibody-mediated rejection of renal transplants. J Am Soc Nephrol 2014; 26:855-63. [PMID: 25145937 DOI: 10.1681/asn.2013121289] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.
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Affiliation(s)
- Hsiao-Hsuan Kuo
- Departments of Immunology and Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio
| | - Ran Fan
- Departments of Immunology and
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293
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Platelets release mitochondria serving as substrate for bactericidal group IIA-secreted phospholipase A2 to promote inflammation. Blood 2014; 124:2173-83. [PMID: 25082876 DOI: 10.1182/blood-2014-05-573543] [Citation(s) in RCA: 446] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mitochondrial DNA (mtDNA) is a highly potent inflammatory trigger and is reportedly found outside the cells in blood in various pathologies. Platelets are abundant in blood where they promote hemostasis. Although lacking a nucleus, platelets contain functional mitochondria. On activation, platelets produce extracellular vesicles known as microparticles. We hypothesized that activated platelets could also release their mitochondria. We show that activated platelets release respiratory-competent mitochondria, both within membrane-encapsulated microparticles and as free organelles. Extracellular mitochondria are found in platelet concentrates used for transfusion and are present at higher levels in those that induced acute reactions (febrile nonhemolytic reactions, skin manifestations, and cardiovascular events) in transfused patients. We establish that the mitochondrion is an endogenous substrate of secreted phospholipase A2 IIA (sPLA2-IIA), a phospholipase otherwise specific for bacteria, likely reflecting the ancestral proteobacteria origin of mitochondria. The hydrolysis of the mitochondrial membrane by sPLA2-IIA yields inflammatory mediators (ie, lysophospholipids, fatty acids, and mtDNA) that promote leukocyte activation. Two-photon microscopy in live transfused animals revealed that extracellular mitochondria interact with neutrophils in vivo, triggering neutrophil adhesion to the endothelial wall. Our findings identify extracellular mitochondria, produced by platelets, at the midpoint of a potent mechanism leading to inflammatory responses.
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294
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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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295
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Schubert S, Weyrich AS, Rowley JW. A tour through the transcriptional landscape of platelets. Blood 2014; 124:493-502. [PMID: 24904119 PMCID: PMC4110657 DOI: 10.1182/blood-2014-04-512756] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 05/30/2014] [Indexed: 02/07/2023] Open
Abstract
The RNA code found within a platelet and alterations of that code continue to shed light onto the mechanistic underpinnings of platelet function and dysfunction. It is now known that features of messenger RNA (mRNA) in platelets mirror those of nucleated cells. This review serves as a tour guide for readers interested in developing a greater understanding of platelet mRNA. The tour provides an in-depth and interactive examination of platelet mRNA, especially in the context of next-generation RNA sequencing. At the end of the expedition, the reader will have a better grasp of the topography of platelet mRNA and how it impacts platelet function in health and disease.
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Affiliation(s)
| | - Andrew S Weyrich
- The Molecular Medicine Program and Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT
| | - Jesse W Rowley
- The Molecular Medicine Program and Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT
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296
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Hottz ED, Medeiros-de-Moraes IM, Vieira-de-Abreu A, de Assis EF, Vals-de-Souza R, Castro-Faria-Neto HC, Weyrich AS, Zimmerman GA, Bozza FA, Bozza PT. Platelet activation and apoptosis modulate monocyte inflammatory responses in dengue. THE JOURNAL OF IMMUNOLOGY 2014; 193:1864-72. [PMID: 25015827 DOI: 10.4049/jimmunol.1400091] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Dengue is the most prevalent human arbovirus disease in the world. Dengue infection has a large spectrum of clinical manifestations, from self-limited febrile illness to severe syndromes accompanied by bleeding and shock. Thrombocytopenia and vascular leak with altered cytokine profiles in plasma are features of severe dengue. Although monocytes have been recognized as important sources of cytokines in dengue, the contributions of platelet-monocyte interactions to inflammatory responses in dengue have not been addressed. Patients with dengue were investigated for platelet-monocyte aggregate formation. Platelet-induced cytokine responses by monocytes and underlying mechanisms were also investigated in vitro. We observed increased levels of platelet-monocyte aggregates in blood samples from patients with dengue, especially patients with thrombocytopenia and increased vascular permeability. Moreover, the exposure of monocytes from healthy volunteers to platelets from patients with dengue induced the secretion of the cytokines IL-1β, IL-8, IL-10 and MCP-1, whereas exposure to platelets from healthy volunteers only induced the secretion of MCP-1. In addition to the well-established modulation of monocyte cytokine responses by activated platelets through P-selectin binding, we found that interaction of monocytes with apoptotic platelets mediate IL-10 secretion through phosphatidylserine recognition in platelet-monocyte aggregates. Moreover, IL-10 secretion required platelet-monocyte contact but not phagocytosis. Together, our results demonstrate that activated and apoptotic platelets aggregate with monocytes during dengue infection and signal specific cytokine responses that may contribute to the pathogenesis of dengue.
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Affiliation(s)
- Eugenio D Hottz
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil; Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro 21040-360, Brazil; Department of Medicine, University of Utah, Salt Lake City, UT 84112
| | - Isabel M Medeiros-de-Moraes
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil
| | - Adriana Vieira-de-Abreu
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil; Department of Medicine, University of Utah, Salt Lake City, UT 84112
| | - Edson F de Assis
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil
| | - Rogério Vals-de-Souza
- Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro 21040-360, Brazil
| | - Hugo C Castro-Faria-Neto
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil
| | - Andrew S Weyrich
- Department of Medicine, University of Utah, Salt Lake City, UT 84112; Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112; and
| | - Guy A Zimmerman
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil; Department of Medicine, University of Utah, Salt Lake City, UT 84112
| | - Fernando A Bozza
- Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro 21040-360, Brazil; Instituto D'Or de Pesquisa e Ensino, Rio de Janeiro 22281-110, Brazil
| | - Patrícia T Bozza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro 21045-900, Brazil;
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297
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Feng Y, Dorhoi A, Mollenkopf HJ, Yin H, Dong Z, Mao L, Zhou J, Bi A, Weber S, Maertzdorf J, Chen G, Chen Y, Kaufmann SHE. Platelets direct monocyte differentiation into epithelioid-like multinucleated giant foam cells with suppressive capacity upon mycobacterial stimulation. J Infect Dis 2014; 210:1700-10. [PMID: 24987031 PMCID: PMC4224136 DOI: 10.1093/infdis/jiu355] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Epithelioid, foam, and multinucleated giant cells (MNGCs) are characteristics of tuberculosis granulomas, yet the precise genesis and functions of these transformed macrophages are unclear. We evaluated the role of platelets as drivers of macrophage transformation in mycobacterial infection. METHODS We employed flow cytometry and microscopy to assess cellular phenotype and phagocytosis. Immune assays allowed quantification of cytokines and chemokines, whereas gene microarray technology was applied to estimate global transcriptome alterations. Immunohistochemical investigations of tuberculosis granulomas substantiated our findings at the site of infection. RESULTS Monocytes differentiated in presence of platelets (MP-Macs) acquired a foamy, epithelioid appearance and gave rise to MNGCs (MP-MNGCs). MP-Macs up-regulated activation markers, phagocytosed mycobacteria, and released abundant interleukin 10. Upon extended culture, MP-Macs shared transcriptional features with epithelioid cells and M2 macrophages and up-regulated CXCL5 transcripts. In line with this, CXCL5 concentrations were significantly increased in airways of active tuberculosis patients. The platelet-specific CD42b antigen was detected in MP-Macs, likewise in macrophages, MNGCs, and epithelioid cells within tuberculosis granulomas, along with the platelet aggregation-inducing factor PDPN. CONCLUSIONS Platelets drive macrophage differentiation into MNGCs with characteristics of epithelioid, foam, and giant cells observed in tuberculosis granulomas. Our data define platelets as novel participants in tuberculosis pathogenesis.
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Affiliation(s)
- Yonghong Feng
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany Shanghai Key Lab of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University, China
| | - Anca Dorhoi
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Hans-Joachim Mollenkopf
- Max Planck Institute for Infection Biology, Core Facility Microarray/Genomics, Berlin, Germany
| | - Hongyun Yin
- Shanghai Key Lab of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University, China
| | - Zhengwei Dong
- Department of Pathology, Shanghai Pulmonary Hospital, Tongji University
| | - Ling Mao
- Shanghai Key Lab of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University, China
| | - Jun Zhou
- Department of Pathology, Shanghai Pulmonary Hospital, Tongji University
| | - Aixiao Bi
- Shanghai Key Lab of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University, China
| | - Stephan Weber
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Jeroen Maertzdorf
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Gang Chen
- Department of Pathology, Shanghai Pulmonary Hospital, Tongji University
| | - Yang Chen
- Bioinformatics Division and Center for Synthetic and Systems Biology, TNLIST, Department of Automation, Tsinghua University, Beijing, China
| | - Stefan H E Kaufmann
- Department of Immunology, Max Planck Institute for Infection Biology, Berlin, Germany
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298
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Detection of apoptosis-associated microRNA in human apheresis platelets during storage by quantitative real-time polymerase chain reaction analysis. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2014; 12:541-7. [PMID: 24960647 DOI: 10.2450/2014.0291-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 02/13/2014] [Indexed: 01/13/2023]
Abstract
BACKGROUND Platelet transfusion is an essential part of the treatment of a variety of conditions such as thrombocytopenia and qualitative platelet disorders. As indicated in previous reports, during in vitro storage, platelets undergo morphological and physiological changes collectively known as the platelet storage lesion. Apoptosis is a programmed process of cell death, which has been considered as an important cause of platelet storage lesion under the common storage conditions in standard blood banks. Platelets are anucleate blood cells, but contain significant amounts of microRNA (miRNA, miR), which may play an important role in the regulation of gene expression. Drawing on previously published reports on cell apoptosis, we selected 49 miRNA for analysis to explore whether miRNA are of importance during the storage of platelets. MATERIALS AND METHODS We used quantitative real-time polymerase chain reaction analysis to determine the levels of expression of miRNA in apheresis platelets at different times of storage. Bioinformatics analysis was applied to explore target genes and the main functions of the selected miRNA. RESULTS Our observations suggest that apheresis platelets contain large amounts of apoptosis-associated miRNA. The levels of expression of 25 miRNA remained high and ten of these miRNA showed different expression from that at day 0. Of these ten miRNA, hsa-miR-326, hsa-miR-96, hsa-miR-16, hsa-miR-155 and hsa-miR-150 were up-regulated, while hsa-miR-7, hsa-miR-145, hsa-miR-24, hsa-miR-25 and hsa-miR-15a were down-regulated. The markedly increased expression of hsa-miR-326 in all platelets is noteworthy (p<0.001). DISCUSSION Since Bcl-xl and Bak1, members of the Bcl-2 family, are the targets of hsa-miR-326, our findings suggest that hsa-miR-326 may be involved in platelet apoptosis during storage.
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Jung H, Gkogkas CG, Sonenberg N, Holt CE. Remote control of gene function by local translation. Cell 2014; 157:26-40. [PMID: 24679524 PMCID: PMC3988848 DOI: 10.1016/j.cell.2014.03.005] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 02/04/2014] [Accepted: 03/04/2014] [Indexed: 12/12/2022]
Abstract
The subcellular position of a protein is a key determinant of its function. Mounting evidence indicates that RNA localization, where specific mRNAs are transported subcellularly and subsequently translated in response to localized signals, is an evolutionarily conserved mechanism to control protein localization. On-site synthesis confers novel signaling properties to a protein and helps to maintain local proteome homeostasis. Local translation plays particularly important roles in distal neuronal compartments, and dysregulated RNA localization and translation cause defects in neuronal wiring and survival. Here, we discuss key findings in this area and possible implications of this adaptable and swift mechanism for spatial control of gene function.
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Affiliation(s)
- Hosung Jung
- Department of Anatomy, Brain Research Institute, and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, South Korea
| | - Christos G Gkogkas
- Patrick Wild Centre, Centre for Integrative Physiology, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada.
| | - Christine E Holt
- Department of Physiology Development and Neuroscience, Anatomy Building, Downing Street, University of Cambridge, Cambridge CB2 3DY, UK.
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300
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Platelets join the world of "Omics". Blood 2014; 123:2446-7. [PMID: 24744250 DOI: 10.1182/blood-2014-02-557389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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