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Witkowski M, Landmesser U, Rauch U. Tissue factor as a link between inflammation and coagulation. Trends Cardiovasc Med 2016; 26:297-303. [DOI: 10.1016/j.tcm.2015.12.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 12/08/2015] [Accepted: 12/08/2015] [Indexed: 10/22/2022]
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102
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Rondina MT, Freitag M, Pluthero FG, Kahr WHA, Rowley JW, Kraiss LW, Franks Z, Zimmerman GA, Weyrich AS, Schwertz H. Non-genomic activities of retinoic acid receptor alpha control actin cytoskeletal events in human platelets. J Thromb Haemost 2016; 14:1082-94. [PMID: 26848712 PMCID: PMC5497578 DOI: 10.1111/jth.13281] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Indexed: 12/29/2022]
Abstract
UNLABELLED Essentials Platelets employ proteins/signaling pathways traditionally thought reserved for nuclear niche. We determined retinoic-acid-receptor alpha (RARα) expression and function in human platelets. RARα/actin-related protein-2/3 complex (Arp2/3) interact via non-genomic signaling in platelets. RARα regulates Arp2/3-mediated actin cytoskeletal dynamics and platelet spreading. SUMMARY Background Platelets utilize proteins and pathways classically reserved for the nuclear niche. Methods We determined whether human platelets express retinoic-acid-receptor family members, traditionally thought of as nuclear transcription factors, and deciphered the function of RARα. Results We found that RARα is robustly expressed in human platelets and megakaryocytes and interacts directly with actin-related protein-2/3 complex (Arp2/3) subunit 5 (Arp2/3s5). Arp2/3s5 co-localized with RARα in situ and regulated platelet cytoskeletal processes. The RARα ligand all-trans retinoic acid (atRA) disrupted RARα-Arp2/3 interactions. When isolated human platelets were treated with atRA, rapid cytoskeletal events (e.g. platelet spreading) were inhibited. In addition, when platelets were cultured for 18 h in the presence of atRA, actin-dependent morphological changes (e.g. extended cell body formation) were similarly inhibited. Using in vitro actin branching assays, RARα and Arp2/3-regulated complex actin branch formation was demonstrated. Consistent with inhibition of cytoskeletal processes in platelets, atRA, when added to this branching assay, resulted in dysregulated actin branching. Conclusion Our findings identify a previously unknown mechanism by which RARα regulates Arp2/3-mediated actin cytoskeletal dynamics through a non-genomic signaling pathway. These findings have broad implications in both nucleated and anucleate cells, where actin cytoskeletal events regulate cell morphology, movement and division.
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Affiliation(s)
- M T Rondina
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
- Department of Internal Medicine, George E. Wahlen Salt Lake City VAMC, Salt Lake City, UT, USA
| | - M Freitag
- Department of Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany
| | - F G Pluthero
- Program in Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - W H A Kahr
- Program in Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
- Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, ON, Canada
| | - J W Rowley
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA
| | - L W Kraiss
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA
- Division of Vascular Surgery, Department of Surgery, University of Utah, Salt Lake City, UT, USA
| | - Z Franks
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA
| | - G A Zimmerman
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - A S Weyrich
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - H Schwertz
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA
- Department of Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany
- Division of Vascular Surgery, Department of Surgery, University of Utah, Salt Lake City, UT, USA
- Lichtenberg-Professor for Experimental Hemostasis, University of Greifswald, Greifswald, Germany
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Sirotkina OV, Laskovets AB, Andoskin PA, Emelyanov AK, Zabotina AM, Vavilova TV. Increase in GP IIb-IIIa and P2Y12 receptors in activated platelets as the possible indicator of de novo protein synthesis. Mol Biol 2016. [DOI: 10.1134/s0026893316010180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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104
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Abstract
Intron retention (IR) is a form of alternative splicing that can impact mRNA levels through nonsense-mediated decay or by nuclear mRNA detention. A complex, dynamic IR pattern has been described in maturing mammalian granulocytes, but it is unknown whether IR occurs broadly in other hematopoietic lineages. We globally assessed IR in primary maturing mammalian erythroid and megakaryocyte (MK) lineages as well as their common progenitor cells (MEPs). Both lineages exhibit an extensive differential IR program involving hundreds of introns and genes with an overwhelming loss of IR in erythroid cells and MKs compared to MEPs. Moreover, complex IR patterns were seen throughout murine erythroid maturation. Similarly complex patterns were observed in human erythroid differentiation, but not involving the murine orthologous introns or genes. Despite the common origin of erythroid cells and MKs, and overlapping gene expression patterns, the MK IR program is entirely distinct from that of the erythroid lineage with regards to introns, genes, and affected gene ontologies. Importantly, our results suggest that IR serves to broadly regulate mRNA levels. These findings highlight the importance of this understudied form of alternative splicing in gene regulation and provide a useful resource for studies on gene expression in the MK and erythroid lineages.
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105
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Abstract
Enterohemorrhagic Escherichia coli (EHEC) is a highly pathogenic bacterial strain capable of causing watery or bloody diarrhea, the latter termed hemorrhagic colitis, and hemolytic-uremic syndrome (HUS). HUS is defined as the simultaneous development of non-immune hemolytic anemia, thrombocytopenia, and acute renal failure. The mechanism by which EHEC bacteria colonize and cause severe colitis, followed by renal failure with activated blood cells, as well as neurological symptoms, involves the interaction of bacterial virulence factors and specific pathogen-associated molecular patterns with host cells as well as the host response. The innate immune host response comprises the release of antimicrobial peptides as well as cytokines and chemokines in addition to activation and/or injury to leukocytes, platelets, and erythrocytes and activation of the complement system. Some of the bacterial interactions with the host may be protective in nature, but, when excessive, contribute to extensive tissue injury, inflammation, and thrombosis, effects that may worsen the clinical outcome of EHEC infection. This article describes aspects of the host response occurring during EHEC infection and their effects on specific organs.
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106
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Swieringa F, Baaten CCFMJ, Verdoold R, Mastenbroek TG, Rijnveld N, van der Laan KO, Breel EJ, Collins PW, Lancé MD, Henskens YMC, Cosemans JMEM, Heemskerk JWM, van der Meijden PEJ. Platelet Control of Fibrin Distribution and Microelasticity in Thrombus Formation Under Flow. Arterioscler Thromb Vasc Biol 2016; 36:692-9. [PMID: 26848157 DOI: 10.1161/atvbaha.115.306537] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/15/2016] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Platelet- and fibrin-dependent thrombus formation is regulated by blood flow and exposure of collagen and tissue factor. However, interactions between these blood-borne and vascular components are not well understood. APPROACH AND RESULTS Here, we developed a method to assess whole-blood thrombus formation on microspots with defined amounts of collagen and tissue factor, allowing determination of the mechanical properties and intrathrombus composition. Confining the collagen content resulted in diminished platelet deposition and fibrin formation at high shear flow conditions, but this effect was compensated by a larger thrombus size and increased accumulation of fibrin in the luminal regions of the thrombi at the expense of the base regions. These thrombi were more dependent on tissue factor-triggered thrombin generation. Microforce nanoindentation analysis revealed a significantly increased microelasticity of thrombi with luminal-oriented fibrin. At a low shear rate, fibrin fibers tended to luminally cover the thrombi, again resulting in a higher microelasticity. Studies with blood from patients with distinct hemostatic insufficiencies indicated an impairment in the formation of a platelet-fibrin thrombus in the cases of dilutional coagulopathy, thrombocytopenia, Scott syndrome, and hemophilia B. CONCLUSIONS Taken together, our data indicate that (1) thrombin increases the platelet thrombus volume; (2) tissue factor drives the formation of fibrin outside of the platelet thrombus; (3) limitation of platelet adhesion redirects fibrin from bottom to top of the thrombus; (4) a lower shear rate promotes thrombus coverage with fibrin; (5) the fibrin distribution pattern determines thrombus microelasticity; and (6) the thrombus-forming process is reduced in patients with diverse hemostatic defects.
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Affiliation(s)
- Frauke Swieringa
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Constance C F M J Baaten
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Remco Verdoold
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Tom G Mastenbroek
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Niek Rijnveld
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Koen O van der Laan
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Ernst J Breel
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Peter W Collins
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Marcus D Lancé
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Yvonne M C Henskens
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Judith M E M Cosemans
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Johan W M Heemskerk
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Paola E J van der Meijden
- From the Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands (F.S., C.C.F.M.J.B., R.V., T.G.M., J.M.E.M.C., J.W.M.H., P.E.J.v.d.M.); Research and Development, Optics11, Amsterdam, The Netherlands (N.R., K.O.v.d.L., E.J.B.); Arthur Bloom Haemophilia Centre, Cardiff Institute of Infection & Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom (P.W.C.); and Central Diagnostic Laboratory (Y.M.C.H.), Departments of Anaesthesiology (M.D.L.) and Internal Medicine (Y.M.C.H.), Maastricht University Medical Center, Maastricht, The Netherlands.
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107
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Circular RNA enrichment in platelets is a signature of transcriptome degradation. Blood 2015; 127:e1-e11. [PMID: 26660425 DOI: 10.1182/blood-2015-06-649434] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 12/01/2015] [Indexed: 02/07/2023] Open
Abstract
In platelets, splicing and translation occur in the absence of a nucleus. However, the integrity and stability of mRNAs derived from megakaryocyte progenitor cells remain poorly quantified on a transcriptome-wide level. As circular RNAs (circRNAs) are resistant to degradation by exonucleases, their abundance relative to linear RNAs can be used as a surrogate marker for mRNA stability in the absence of transcription. Here we show that circRNAs are enriched in human platelets 17- to 188-fold relative to nucleated tissues and 14- to 26-fold relative to samples digested with RNAse R to selectively remove linear RNA. We compare RNAseq read depths inside and outside circRNAs to provide in silico evidence of transcript circularity, show that exons within circRNAs are enriched on average 12.7 times in platelets relative to nucleated tissues and identify 3162 genes significantly enriched for circRNAs, including some where all RNAseq reads appear to be derived from circular molecules. We also confirm that this is a feature of other anucleate cells through transcriptome sequencing of mature erythrocytes, demonstrate that circRNAs are not enriched in cultured megakaryocytes, and demonstrate that linear RNAs decay more rapidly than circRNAs in platelet preparations. Collectively, these results suggest that circulating platelets have lost >90% of their progenitor mRNAs and that translation in platelets occurs against the backdrop of a highly degraded transcriptome. Finally, we find that transcripts previously classified as products of reverse transcriptase template switching are both enriched in platelets and resistant to decay, countering the recent suggestion that up to 50% of rearranged RNAs are artifacts.
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108
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Ruf W. Diverse packaging of TF into platelets. Thromb Haemost 2015; 114:445. [PMID: 26145707 DOI: 10.1160/th15-06-0451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 06/03/2015] [Indexed: 11/05/2022]
Affiliation(s)
- Wolfram Ruf
- Wolfram Ruf, Center for Thrombosis and Haemostasis, University Medical Center, Mainz, Germany, E-mail:
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109
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Abstract
Platelets are anucleate blood cells, long known to be critically involved in hemostasis and thrombosis. In addition to their role in blood clots, increasing evidence reveals significant roles for platelets in inflammation and immunity. However, the notion that platelets represent immune cells is not broadly recognized in the field of Physiology. This article reviews the role of platelets in inflammation and immune responses, and highlights their interactions with other immune cells, including examples of major functional consequences of these interactions.
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Affiliation(s)
- Fong W Lam
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey VA Medical Center, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA
| | - K Vinod Vijayan
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey VA Medical Center, Houston, Texas, USA
- Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA
| | - Rolando E Rumbaut
- Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey VA Medical Center, Houston, Texas, USA
- Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA
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110
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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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111
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Abdel-Bakky MS, Helal GK, El-Sayed EM, Saad AS. Carbon tetrachloride-induced liver injury in mice is tissue factor dependent. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 39:1199-1205. [PMID: 25982951 DOI: 10.1016/j.etap.2015.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 02/17/2015] [Accepted: 02/19/2015] [Indexed: 06/04/2023]
Abstract
Tissue factor (TF) is a membranous glycoprotein that activates the coagulation system when blood vessels or tissues are damaged. TF was up-regulated in monocrotaline (MCT)/lipopolysaccharide (LPS) hepatotoxicity model. The present study aimed to test the hypothesis that TF-dependent fibrin deposition occurs in liver toxicity induced by CCl4 in mice. Pericentral deposition of TF and fibrin is induced after CCl4-induced liver toxicity. The toxicity was evaluated by determination of serum activities of ALT, AST and ALP as well as GSH content and histopathological changes. The results showed that injection of mice with TF-antisense deoxyoligonucleotide (TF-AS) prevented the accumulation of TF and fibrin in the hepatic tissues. Furthermore, it significantly restored blood biochemical parameters, GSH content and distorted histopathological features caused by CCl4. The current study demonstrates that TF activation is associated with CCl4-induced liver injury. Furthermore, administration of TF-AS successfully prevented this type of liver injury.
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Affiliation(s)
- M S Abdel-Bakky
- Faculty of pharmacy, Al-Azhar university, Cairo 11884 Egypt; Faculty of pharmacy, Aljouf university, Aljouf, Saudi Arabia
| | - G K Helal
- Faculty of pharmacy, Al-Azhar university, Cairo 11884 Egypt; Faculty of pharmacy, Nahda university, Bani Suef, Egypt
| | - E M El-Sayed
- Faculty of pharmacy, Al-Azhar university, Cairo 11884 Egypt
| | - A S Saad
- Faculty of Pharmacy, Delta University for Science and Technology, Mansoura, Egypt.
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112
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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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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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114
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Ohe K, Hagiwara M. Modulation of alternative splicing with chemical compounds in new therapeutics for human diseases. ACS Chem Biol 2015; 10:914-24. [PMID: 25560473 DOI: 10.1021/cb500697f] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alternative splicing is a critical step where a limited number of human genes generate a complex and diverse proteome. Various diseases, including inherited diseases with abnormalities in the "genome code," have been found to result in an aberrant mis-spliced "transcript code" with correlation to the resulting phenotype. Chemical compound-based and nucleic acid-based strategies are trying to target this mis-spliced "transcript code". We will briefly mention about how to obtain splicing-modifying-compounds by high-throughput screening and overview of what is known about compounds that modify splicing pathways. The main focus will be on RNA-binding protein kinase inhibitors. In the main text, we will refer to diseases where splicing-modifying-compounds have been intensively investigated, with comparison to nucleic acid-based strategies. The information on their involvement in mis-splicing as well as nonsplicing events will be helpful in finding better compounds with less off-target effects for future implications in mis-splicing therapy.
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Affiliation(s)
- Kenji Ohe
- †Department of Anatomy and Developmental Biology and ‡Training Program of Leaders for Integrated Medical System for Fruitful Healthy-Longevity Society (LIMS), Kyoto University Graduate School of Medicine, Kyoto 606-8315, Japan
| | - Masatoshi Hagiwara
- †Department of Anatomy and Developmental Biology and ‡Training Program of Leaders for Integrated Medical System for Fruitful Healthy-Longevity Society (LIMS), Kyoto University Graduate School of Medicine, Kyoto 606-8315, Japan
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115
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Nording HM, Seizer P, Langer HF. Platelets in inflammation and atherogenesis. Front Immunol 2015; 6:98. [PMID: 25798138 PMCID: PMC4351644 DOI: 10.3389/fimmu.2015.00098] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/19/2015] [Indexed: 12/12/2022] Open
Abstract
Platelets contribute to processes beyond thrombus formation and may play a so far underestimated role as an immune cell in various circumstances. This review outlines immune functions of platelets in host defense, but also how they may contribute to mechanisms of infectious diseases. A particular emphasis is placed on the interaction of platelets with other immune cells. Furthermore, this article outlines the features of atherosclerosis as an inflammatory vascular disease highlighting the role of platelet crosstalk with cellular and soluble factors involved in atheroprogression. Understanding, how platelets influence these processes of vascular remodeling will shed light on their role for tissue homeostasis beyond intravascular thrombosis. Finally, translational implications of platelet-mediated inflammation in atherosclerosis are discussed.
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Affiliation(s)
- Henry M. Nording
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
- Section for Cardioimmunology, Eberhard Karls-University Tübingen, Tübingen, Germany
| | - Peter Seizer
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
| | - Harald F. Langer
- University Clinic for Cardiology and Cardiovascular Medicine, Eberhard Karls-University Tübingen, Tübingen, Germany
- Section for Cardioimmunology, Eberhard Karls-University Tübingen, Tübingen, Germany
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116
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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: 285] [Impact Index Per Article: 31.7] [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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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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118
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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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Abstract
Epidemiologic studies have revealed that modification of the levels of individual components of the hemostatic system may have effects on the development of thrombosis or hemorrhage. To maintain the necessary equilibrium, the hemostatic system is finely regulated. It is known that acquired factors and/or alterations in genes (single-nucleotide polymorphisms or mutations) may be the cause of interindividual differences or exacerbated levels of hemostatic proteins in plasma, but there are still many non-characterized factors that provoke such variations. The search for new elements, such as microRNAs (miRNAs), a family of small non-coding RNAs that are novel regulators of protein expression, may reveal an additional layer at which to investigate the causes of hemostatic diseases. In this review, we discuss the latest developments in research into the role of miRNAs in the regulation of several hemostatic factors, and the potential use of miRNAs as prognostic or diagnostic tools in hemostasis and thrombosis.
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Affiliation(s)
- R Teruel-Montoya
- Centro Regional de Hemodonación, IMIB-Arrixaca, University of Murcia, Murcia, Spain
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120
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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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121
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Rao AK, Freishtat RJ, Jalagadugula G, Singh A, Mao G, Wiles A, Cheung P, Boden G. Alterations in insulin-signaling and coagulation pathways in platelets during hyperglycemia-hyperinsulinemia in healthy non-diabetic subject. Thromb Res 2014; 134:704-10. [PMID: 25042561 PMCID: PMC4148207 DOI: 10.1016/j.thromres.2014.06.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/25/2014] [Accepted: 06/26/2014] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Diabetes mellitus (DM) is a prothrombotic and proinflammatory state. Hyperglycemia (HG) is encountered even in patients without DM. We have shown that combined HG and hyperinsulinemia (HI) in healthy non-diabetic subjects increased circulating tissue factor (TF) and thrombin generation. To understand the changes in platelet and monocyte pathways induced by combined HG and HI in healthy non-diabetic state, we performed whole genome expression profiling of leukocyte-depleted platelets and monocytes before and after 24 hours of combined HG (glucose ~200mg/dL) and HI by glucose infusion clamp in a healthy non-diabetic subject. RESULTS We defined time-dependent differential mRNA expression (24 versus 0 hour fold change (FC) ≥ 2) common to platelets and monocytes. Ingenuity Pathways Analysis revealed alterations in canonical insulin receptor signaling and coagulation pathways. A preliminary group of 9 differentially expressed genes was selected for qRT-PCR confirmation. Platelet 24 hour sample was compared to the 0 hour sample plus 4 controls. Five transcripts in platelets and 6 in monocytes were confirmed. Platelet GSK3B and PTPN1 were upregulated, and STXBP4 was downregulated in insulin signaling, and F3 and TFPI were upregulated in coagulation pathways. Monocyte, PIK3C3, PTPN11 and TFPI were downregulated. Platelet GSKβ3 and PTPN11 protein and TF antigen in platelets and monocytes was increased. CONCLUSIONS Even in non-diabetic state, HG+HI for 24 hours induces changes in platelets and monocytes. They suggest downregulation of insulin signaling and upregulation of TF. Further studies are needed to elucidate cellular alterations leading to the prothrombotic and proinflammatory state in DM.
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Affiliation(s)
- A Koneti Rao
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, USA; Department of Medicine, Temple University School of Medicine, Philadelphia, PA, USA.
| | - Robert J Freishtat
- Division of Emergency Medicine, Children's National Medical Center, Washington, DC, USA
| | - Gauthami Jalagadugula
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - Anamika Singh
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - Guangfen Mao
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - Andrew Wiles
- Division of Emergency Medicine, Children's National Medical Center, Washington, DC, USA
| | - Peter Cheung
- General Clinical Research Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - Guenther Boden
- Department of Medicine, Temple University School of Medicine, Philadelphia, PA, USA; General Clinical Research Center, Temple University School of Medicine, Philadelphia, PA, USA
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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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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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124
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125
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Human podoplanin-positive monocytes and platelets enhance lymphangiogenesis through the activation of the podoplanin/CLEC-2 axis. Mol Ther 2014; 22:1518-1529. [PMID: 24736277 DOI: 10.1038/mt.2014.61] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 03/18/2014] [Indexed: 01/12/2023] Open
Abstract
Emerging studies suggested that murine podoplanin-positive monocytes (PPMs) are involved in lymphangiogenesis. The goal of this study was to demonstrate the therapeutic lymphangiogenesis of human PPMs by the interaction with platelets. Aggregation culture of human peripheral blood mononuclear cells (PBMCs) resulted in cellular aggregates termed hematospheres. During 5-day culture, PPMs expanded exponentially and expressed several lymphatic endothelial cell-specific markers including vascular endothelial growth factor receptor (VEGFR)-3 and well-established lymphangiogenic transcription factors. Next, we investigated the potential interaction of PPMs with platelets that had C-type lectin-like receptor-2 (CLEC-2), a receptor of podoplanin. In vitro coculture of PPMs and platelets stimulated PPMs to strongly express lymphatic endothelial markers and upregulate lymphangiogenic cytokines. Recombinant human CLEC-2 also stimulated PPMs through Akt and Erk signaling. Likewise, platelets in coculture with PPMs augmented secretion of a lymphangiogenic cytokine, interleukin (IL)-1-β, via podoplanin/CLEC-2 axis. The supernatant obtained from coculture was able to enhance the migration, viability, and proliferation of lymphatic endothelial cell. Local injection of hematospheres with platelets significantly increased lymphatic neovascularization and facilitated wound healing in the full-thickness skin wounds of nude mice. Cotreatment with PPMs and platelets augments lymphangiogenesis through podoplanin/CLEC-2 axis, which thus would be a promising novel strategy of cell therapy to treat human lymphatic vessel disease.
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126
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Iwase H, Ezzelarab MB, Ekser B, Cooper DKC. The role of platelets in coagulation dysfunction in xenotransplantation, and therapeutic options. Xenotransplantation 2014; 21:201-20. [PMID: 24571124 DOI: 10.1111/xen.12085] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 01/08/2014] [Indexed: 12/11/2022]
Abstract
Xenotransplantation could resolve the increasing discrepancy between the availability of deceased human donor organs and the demand for transplantation. Most advances in this field have resulted from the introduction of genetically engineered pigs, e.g., α1,3-galactosyltransferase gene-knockout (GTKO) pigs transgenic for one or more human complement-regulatory proteins (e.g., CD55, CD46, CD59). Failure of these grafts has not been associated with the classical features of acute humoral xenograft rejection, but with the development of thrombotic microangiopathy in the graft and/or consumptive coagulopathy in the recipient. Although the precise mechanisms of coagulation dysregulation remain unclear, molecular incompatibilities between primate coagulation factors and pig natural anticoagulants exacerbate the thrombotic state within the xenograft vasculature. Platelets play a crucial role in thrombosis and contribute to the coagulation disorder in xenotransplantation. They are therefore important targets if this barrier is to be overcome. Further genetic manipulation of the organ-source pigs, such as pigs that express one or more coagulation-regulatory genes (e.g., thrombomodulin, endothelial protein C receptor, tissue factor pathway inhibitor, CD39), is anticipated to inhibit platelet activation and the generation of thrombus. In addition, adjunctive pharmacologic anti-platelet therapy may be required. The genetic manipulations that are currently being tested are reviewed, as are the potential pharmacologic agents that may prove beneficial.
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Affiliation(s)
- Hayato Iwase
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
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127
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Kalev-Zylinska ML, Green TN, Morel-Kopp MC, Sun PP, Park YE, Lasham A, During MJ, Ward CM. N-methyl-D-aspartate receptors amplify activation and aggregation of human platelets. Thromb Res 2014; 133:837-47. [PMID: 24593912 DOI: 10.1016/j.thromres.2014.02.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 01/23/2014] [Accepted: 02/13/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND Glutamate is stored in platelet dense granules and large amounts (>400 μM) are released during thrombus formation. N-methyl-d-aspartate glutamate receptors (NMDARs) have been shown in platelets but their roles are unclear. MATERIALS AND METHODS Platelet activation indices (CD62P expression and PAC-1 binding) and platelet aggregation were tested in the presence of well-characterized agonists (glutamate, NMDA, glycine) and antagonists (MK-801, memantine, AP5) of neuronal NMDARs. Expression of NMDAR subunits in platelets was determined. RESULTS NMDAR agonists facilitated and NMDAR antagonists inhibited platelet activation and aggregation. Low concentrations (100 μM) of MK-801 and memantine reduced adrenaline-induced CD62P expression by 47 ± 5 and 42 ± 3%, respectively, and inhibited adrenaline-induced platelet aggregation by 17 ± 6 and 25 ± 5%, respectively (P<0.05). AP5 caused less inhibition of platelet function, requiring concentrations of at least 250 μM to inhibit aggregation. NMDAR agonists did not aggregate platelets by themselves but enhanced aggregation initiated by low concentrations of ADP. Exogenous glutamate helped reverse inhibition of platelet aggregation by riluzole (inhibitor of glutamate release). Compared with seven possible NMDAR subunits in neurons, human platelets contained four: GluN1, GluN2A, GluN2D and GluN3A, a combination rarely seen in neurons. The presence of NMDAR transcripts in platelets implied platelet ability to regulate NMDAR expression presumably 'on demand'. Flow cytometry and electron microscopy demonstrated that in non-activated platelets, NMDAR subunits were contained inside platelets but relocated onto platelet blebs, filopodia and microparticles after platelet activation. CONCLUSIONS Our results support an active role for NMDARs in platelets, in a process that involves activation-dependent receptor relocation towards the platelet surface.
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Affiliation(s)
- Maggie L Kalev-Zylinska
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand; LabPlus Haematology, Auckland District Health Board, Auckland, New Zealand.
| | - Taryn N Green
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Marie-Christine Morel-Kopp
- Department of Haematology and Transfusion Medicine, Royal North Shore Hospital, Sydney, Australia; Northern Blood Research Centre, Kolling Institute, University of Sydney, Sydney, Australia
| | - Paul P Sun
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Young-Eun Park
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Annette Lasham
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Matthew J During
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand; Departments of Molecular Virology, Immunology and Medical Genetics, Neuroscience and Neurological Surgery, Ohio State University, Columbus, OH, USA
| | - Christopher M Ward
- Department of Haematology and Transfusion Medicine, Royal North Shore Hospital, Sydney, Australia; Northern Blood Research Centre, Kolling Institute, University of Sydney, Sydney, Australia
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128
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Liu G, Liu G, Alzoubi K, Umbach AT, Pelzl L, Borst O, Gawaz M, Lang F. Upregulation of store operated Ca channel Orai1, stimulation of Ca(2+) entry and triggering of cell membrane scrambling in platelets by mineralocorticoid DOCA. Kidney Blood Press Res 2014; 38:21-30. [PMID: 24525794 DOI: 10.1159/000355750] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Mineralocorticoid excess leads to vascular injury, which is partially due to hypertension but in addition involves increased concentration of cytosolic Ca(2+) concentration in platelets, key players in the pathophysiology of occlusive vascular disease. Mineralocorticoids are in part effective by rapid nongenomic mechanisms including phosphatidylinositide-3-kinase (PI3K) signaling, which involves activation of the serum & glucocorticoid inducible kinase (SGK) isoforms. SGK1 has in turn been shown to participate in the regulation of the pore forming Ca(2+) channel protein Orai1 in platelets. Orai1 accomplishes entry of Ca(2+), which is in turn known to trigger cell membrane scrambling. Platelets lack nuclei but are able to express protein by translation, which is stimulated by PI3K signaling. The present study explored whether the mineralocorticoid desoxycorticosterone acetate (DOCA) influences platelet Orai1 protein abundance, cytosolic Ca(2+)-activity ([Ca(2+)]i), phosphatidylserine abundance at the cell surface and/or cell volume. METHODS Orai1 protein abundance was estimated utilizing CF™488A conjugated antibodies, [Ca(2+)]i utilizing Fluo3-fluorescence, phosphatidylserine abundance utilizing FITC-labelled annexin V, and cell volume utilizing forward scatter in flow cytometry. RESULTS DOCA (10 µg/ml) treatment of murine platelets was followed by a significant increase of Orai1 protein abundance, [Ca(2+)]i, percentage of phosphatidylserine exposing platelets and platelet swelling. The effect on [Ca(2+)]i, phosphatidylserine abundance and cell volume were completely abrogated by addition of the specific SGK inhibitor EMD638683 (50 µM) CONCLUSIONS: The mineralocorticoid DOCA upregulates Orai1 protein abundance in the cell membrane, thus increasing [Ca(2+)]i and triggering phosphatidylserine abundance, effects paralleled by platelet swelling.
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Affiliation(s)
- Guoxing Liu
- Department of Physiology, University of Tübingen, Tübingen, Germany
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129
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Ezzelarab MB, Liu YW, Lin CC, Long C, Ayares D, Dorling A, Cooper DKC. Role of P-selectin and P-selectin glycoprotein ligand-1 interaction in the induction of tissue factor expression on human platelets after incubation with porcine aortic endothelial cells. Xenotransplantation 2014; 21:16-24. [DOI: 10.1111/xen.12068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Mohamed B. Ezzelarab
- Thomas E. Starzl Transplantation Institute; University of Pittsburgh; Pittsburgh PA USA
| | - Yueh Wei Liu
- Department of Surgery; Kaohsiung Chang Gung Memorial Hospital; Kaoksiung Taiwan
| | - Chih Che Lin
- Thomas E. Starzl Transplantation Institute; University of Pittsburgh; Pittsburgh PA USA
- Department of Surgery; Kaohsiung Chang Gung Memorial Hospital; Kaoksiung Taiwan
| | - Cassandra Long
- Thomas E. Starzl Transplantation Institute; University of Pittsburgh; Pittsburgh PA USA
| | | | - Anthony Dorling
- Division of Transplantation Immunology and Mucosal Biology; MRC Centre for Transplantation; King's College London; Guy's Hospital; London UK
| | - David K. C. Cooper
- Thomas E. Starzl Transplantation Institute; University of Pittsburgh; Pittsburgh PA USA
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130
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Platelets do not express the oxidized or reduced forms of tissue factor. Biochim Biophys Acta Gen Subj 2013; 1840:1188-93. [PMID: 24361609 DOI: 10.1016/j.bbagen.2013.11.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/11/2013] [Accepted: 11/25/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Expression of tissue factor (TF) antigen and activity in platelets is controversial and dependent upon the laboratory and reagents used. Two forms of TF were described: an oxidized functional form and a reduced nonfunctional form that is converted to the active form through the formation of an allosteric disulfide. This study tests the hypothesis that the discrepancies regarding platelet TF expression are due to differential expression of the two forms. METHODS Specific reagents that recognize both oxidized and reduced TF were used in flow cytometry of unactivated and activated platelets and western blotting of whole platelet lysates. TF-dependent activity measurements were used to confirm the results. RESULTS Western blotting analyses of placental TF demonstrated that, in contrast to anti-TF#5, which is directed against the oxidized form of TF, a sheep anti-human TF polyclonal antibody recognizes both the reduced and oxidized forms. Flow cytometric analyses demonstrated that the sheep antibody did not react with the surface of unactivated platelets or platelets activated with thrombin receptor agonist peptide, PAR-1. This observation was confirmed using biotinylated active site-blocked factor (F)VIIa: no binding was observed. Likewise, neither form of TF was detected by western blotting of whole platelet lysates with sheep anti-hTF. Consistent with these observations, no FXa or FIXa generation by FVIIa was detected at the surface of these platelets. Similarly, no TF-related activity was observed in whole blood using thromboelastography. CONCLUSION AND SIGNIFICANCE Platelets from healthy donors do not express either oxidized (functional) or reduced (nonfunctional) forms of TF.
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131
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Kissopoulou A, Jonasson J, Lindahl TL, Osman A. Next generation sequencing analysis of human platelet PolyA+ mRNAs and rRNA-depleted total RNA. PLoS One 2013; 8:e81809. [PMID: 24349131 PMCID: PMC3859545 DOI: 10.1371/journal.pone.0081809] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 10/16/2013] [Indexed: 01/01/2023] Open
Abstract
Background Platelets are small anucleate cells circulating in the blood vessels where they play a key role in hemostasis and thrombosis. Here, we compared platelet RNA-Seq results obtained from polyA+ mRNA and rRNA-depleted total RNA. Materials and Methods We used purified, CD45 depleted, human blood platelets collected by apheresis from three male and one female healthy blood donors. The Illumina HiSeq 2000 platform was employed to sequence cDNA converted either from oligo(dT) isolated polyA+ RNA or from rRNA-depleted total RNA. The reads were aligned to the GRCh37 reference assembly with the TopHat/Cufflinks alignment package using Ensembl annotations. A de novo assembly of the platelet transcriptome using the Trinity software package and RSEM was also performed. The bioinformatic tools HTSeq and DESeq from Bioconductor were employed for further statistical analyses of read counts. Results Consistent with previous findings our data suggests that mitochondrially expressed genes comprise a substantial fraction of the platelet transcriptome. We also identified high transcript levels for protein coding genes related to the cytoskeleton function, chemokine signaling, cell adhesion, aggregation, as well as receptor interaction between cells. Certain transcripts were particularly abundant in platelets compared with other cell and tissue types represented by RNA-Seq data from the Illumina Human Body Map 2.0 project. Irrespective of the different library preparation and sequencing protocols, there was good agreement between samples from the 4 individuals. Eighteen differentially expressed genes were identified in the two sexes at 10% false discovery rate using DESeq. Conclusion The present data suggests that platelets may have a unique transcriptome profile characterized by a relative over-expression of mitochondrially encoded genes and also of genomic transcripts related to the cytoskeleton function, chemokine signaling and surface components compared with other cell and tissue types. The in vivo functional significance of the non-mitochondrial transcripts remains to be shown.
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Affiliation(s)
- Antheia Kissopoulou
- Department of Clinical and Experimental Medicine, University of Linköping, Linköping, Sweden
| | - Jon Jonasson
- Department of Clinical and Experimental Medicine, University of Linköping, Linköping, Sweden
| | - Tomas L. Lindahl
- Department of Clinical and Experimental Medicine, University of Linköping, Linköping, Sweden
| | - Abdimajid Osman
- Department of Clinical and Experimental Medicine, University of Linköping, Linköping, Sweden
- * E-mail:
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132
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Altered expression of platelet proteins and calpain activity mediate hypoxia-induced prothrombotic phenotype. Blood 2013; 123:1250-60. [PMID: 24297866 DOI: 10.1182/blood-2013-05-501924] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Oxygen-compromised environments, such as high altitude, air travel, and sports, and pathological conditions, such as solid tumors, have been suggested to be prothrombotic. Despite the indispensable role of platelets in thrombus formation, the studies linking hypoxia, platelet reactivity, and thrombus formation are limited. In the present study, platelet proteome/reactivity was analyzed to elucidate the acute hypoxia-induced prothrombotic phenotype. Rats exposed to acute simulated hypoxia (282 torr/8% oxygen) demonstrated a decreased bleeding propensity and increased platelet reactivity. Proteomic analysis of hypoxic platelets revealed 27 differentially expressed proteins, including those involved in coagulation. Among these proteins, calpain small subunit 1, a 28-kDa regulatory component for calpain function, was significantly upregulated under hypoxic conditions. Moreover, intraplatelet Ca(2+) level and platelet calpain activity were also found to be in accordance with calpain small subunit 1 expression. The inhibition of calpain activity demonstrated reversal of hypoxia-induced platelet hyperreactivity. The prothrombotic role for calpain was further confirmed by an in vivo model of hypoxia-induced thrombosis. Interestingly, patients who developed thrombosis while at extreme altitude had elevated plasma calpain activities and increased soluble P-selectin level. In summary, this study suggests that augmented calpain activity is associated with increased incidence of thrombosis under hypoxic environments.
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133
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Regulation of vascular function on posttranscriptional level. THROMBOSIS 2013; 2013:948765. [PMID: 24288605 PMCID: PMC3833109 DOI: 10.1155/2013/948765] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/17/2013] [Indexed: 11/17/2022]
Abstract
Posttranscriptional control of gene expression is crucial for regulating plurality of proteins and functional plasticity of the proteome under (patho)physiologic conditions. Alternative splicing as well as micro (mi)RNA-mediated mechanisms play an important role for the regulation of protein expression on posttranscriptional level. Both alternative splicing and miRNAs were shown to influence cardiovascular functions, such as endothelial thrombogenicity and the vascular tone, by regulating the expression of several vascular proteins and their isoforms, such as Tissue Factor (TF) or the endothelial nitric oxide synthase (eNOS). This review will summarize and discuss the latest findings on the (patho)physiologic role of alternative splicing processes as well as of miRNAs on modulation of vascular functions, such as coagulation, thrombosis, and regulation of the vascular tone.
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134
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Abstract
Clinical and epidemiological studies support a connection between obesity and thrombosis, involving elevated expression of the prothrombotic molecules plasminogen activator inhibitor-1 and tissue factor (TF) and increased platelet activation. Cardiovascular diseases and metabolic syndrome-associated disorders, including obesity, insulin resistance, type 2 diabetes, and hepatic steatosis, involve inflammation elicited by infiltration and activation of immune cells, particularly macrophages, into adipose tissue. Although TF has been clearly linked to a procoagulant state in obesity, emerging genetic and pharmacologic evidence indicate that TF signaling via G protein-coupled protease-activated receptors (PAR2, PAR1) additionally drives multiple aspects of the metabolic syndrome. TF-PAR2 signaling in adipocytes contributes to diet-induced obesity by decreasing metabolism and energy expenditure, whereas TF-PAR2 signaling in hematopoietic and myeloid cells drives adipose tissue inflammation, hepatic steatosis, and insulin resistance. TF-initiated coagulation leading to thrombin-PAR1 signaling also contributes to diet-induced hepatic steatosis and inflammation in certain models. Thus, in obese patients, clinical markers of a prothrombotic state may indicate a risk for the development of complications of the metabolic syndrome. Furthermore, TF-induced signaling could provide new therapeutic targets for drug development at the intersection between obesity, inflammation, and thrombosis.
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135
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Brown GT, Narayanan P, Li W, Silverstein RL, McIntyre TM. Lipopolysaccharide stimulates platelets through an IL-1β autocrine loop. THE JOURNAL OF IMMUNOLOGY 2013; 191:5196-203. [PMID: 24081990 DOI: 10.4049/jimmunol.1300354] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
LPS activates platelets through TLR4, aiding productive sepsis, with stimulated splicing and translation of stored heteronuclear pro-IL-1β RNA. Although the IL-1R type 1 (IL-1R1) receptor for IL-1 shares downstream components with the TLR4 receptor, platelets are not known to express IL-1R1, nor are they known to respond to this cytokine. We show by flow cytometry and Western blotting that platelets express IL-1R1, and that IL-1β and IL-1α stimulate heteronuclear I-1β splicing and translation of the newly made mRNA in platelets. Platelets also respond to the IL-1β they make, which is exclusively associated with shed microparticles. Specific blockade of IL-1R1 with IL-1R antagonist suppressed platelet stimulation by IL-1, so IL-1β stimulates its own synthesis in an autocrine signaling loop. Strikingly, IL-1R antagonist inhibition, pharmacologic or genetic suppression of pro-IL-1β processing to active cytokine by caspase-1, or blockade of de novo protein synthesis also blocked LPS-induced IL-1β mRNA production. Robust stimulation of platelets by LPS therefore also required IL-1β amplification. Activated platelets made IL-1β in vivo as IL-1β rapidly accumulated in occluded murine carotid arteries by posttranscriptional RNA splicing unique to platelets. We conclude that IL-1β is a platelet agonist, that IL-1β acts through an autocrine stimulatory loop, that an IL-1β autocrine loop is required to amplify platelet activation by LPS, and that platelets immobilized in occlusive thrombi are activated over time to produce IL-1β. IL-1 is a new platelet agonist that promotes its own synthesis, connecting thrombosis with immunity.
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Affiliation(s)
- G Thomas Brown
- Department of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio.,Cell Biology Graduate Training Program, Medical Scientist Training Program, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Padmini Narayanan
- Department of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio
| | - Wei Li
- Department of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio
| | - Roy L Silverstein
- Department of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio
| | - Thomas M McIntyre
- Department of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio.,Cell Biology Graduate Training Program, Medical Scientist Training Program, Case Western Reserve University School of Medicine, Cleveland, Ohio
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136
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Kraemer BF, Weyrich AS, Lindemann S. Protein degradation systems in platelets. Thromb Haemost 2013; 110:920-4. [PMID: 24048267 DOI: 10.1160/th13-03-0183] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/28/2013] [Indexed: 01/05/2023]
Abstract
Protein synthesis and degradation are essential processes that allow cells to survive and adapt to their surrounding milieu. In nucleated cells, the degradation and/or cleavage of proteins is required to eliminate aberrant proteins. Cells also degrade proteins as a mechanism for cell signalling and complex cellular functions. Although the last decade has convincingly shown that platelets synthesise proteins, the roles of protein degradation in these anucleate cytoplasts are less clear. Here we review what is known about protein degradation in platelets placing particular emphasis on the proteasome and the cysteine protease calpain.
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Affiliation(s)
- B F Kraemer
- Andrew Weyrich, MD, Eccles Institute of Human Genetics, Department of Internal Medicine, University of Utah, Salt Lake City, Building 533 Room 4220, Salt Lake City, Utah 84112, USA, Tel: +1 801 5850702, Fax: +1 801 5850701, E-mail:
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137
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Platelets mediate increased endothelium permeability in dengue through NLRP3-inflammasome activation. Blood 2013; 122:3405-14. [PMID: 24009231 DOI: 10.1182/blood-2013-05-504449] [Citation(s) in RCA: 250] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dengue is the most frequent hemorrhagic viral disease and re-emergent infection in the world. Although thrombocytopenia is characteristically observed in mild and severe forms of dengue, the role of platelet activation in dengue pathogenesis has not been fully elucidated. We hypothesize that platelets have major roles in inflammatory amplification and increased vascular permeability during severe forms of dengue. Here we investigate interleukin (IL)-1β synthesis, processing, and secretion in platelets during dengue virus (DV) infection and potential contribution of these events to endothelial permeability during infection. We observed increased expression of IL-1β in platelets and platelet-derived microparticles from patients with dengue or after platelet exposure to DV in vitro. We demonstrated that DV infection leads to assembly of nucleotide-binding domain leucine rich repeat containing protein (NLRP3) inflammasomes, activation of caspase-1, and caspase-1-dependent IL-1β secretion. Our findings also indicate that platelet-derived IL-1β is chiefly released in microparticles through mechanisms dependent on mitochondrial reactive oxygen species-triggered NLRP3 inflammasomes. Inflammasome activation and platelet shedding of IL-1β-rich microparticles correlated with signs of increased vascular permeability. Moreover, microparticles from DV-stimulated platelets induced enhanced permeability in vitro in an IL-1-dependent manner. Our findings provide new evidence that platelets contribute to increased vascular permeability in DV infection by inflammasome-dependent release of IL-1β.
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138
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Diamond SL, Purvis J, Chatterjee M, Flamm MH. Systems biology of platelet-vessel wall interactions. Front Physiol 2013; 4:229. [PMID: 23986721 PMCID: PMC3752459 DOI: 10.3389/fphys.2013.00229] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 08/05/2013] [Indexed: 11/28/2022] Open
Abstract
Blood systems biology seeks to quantify outside-in signaling as platelets respond to numerous external stimuli, typically under flow conditions. Platelets can activate via GPVI collagen receptor and numerous G-protein coupled receptors (GPCRs) responsive to ADP, thromboxane, thrombin, and prostacyclin. A bottom-up ODE approach allowed prediction of platelet calcium and phosphoinositides following P2Y1 activation with ADP, either for a population average or single cell stochastic behavior. The homeostasis assumption (i.e., a resting platelet stays resting until activated) was particularly useful in finding global steady states for these large metabolic networks. Alternatively, a top-down approach involving Pairwise Agonist Scanning (PAS) allowed large data sets of measured calcium mobilization to predict an individual's platelet responses. The data was used to train neural network (NN) models of signaling to predict patient-specific responses to combinatorial stimulation. A kinetic description of platelet signaling then allows prediction of inside-out activation of platelets as they experience the complex biochemical milieu at the site of thrombosis. Multiscale lattice kinetic Monte Carlo (LKMC) utilizes these detailed descriptions of platelet signaling under flow conditions where released soluble species are solved by finite element method and the flow field around the growing thrombus is updated using computational fluid dynamics or lattice Boltzmann method. Since hemodynamic effects are included in a multiscale approach, thrombosis can then be predicted under arterial and venous thrombotic conditions for various anatomical geometries. Such systems biology approaches accommodate the effect of anti-platelet pharmacological intervention where COX1 pathways or ADP signaling are modulated in a patient-specific manner.
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Affiliation(s)
- Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania Philadelphia, PA, USA
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139
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Rondina MT, Weyrich AS, Zimmerman GA. Platelets as cellular effectors of inflammation in vascular diseases. Circ Res 2013; 112:1506-19. [PMID: 23704217 DOI: 10.1161/circresaha.113.300512] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Platelets are chief effector cells in hemostasis. In addition, they are multifaceted inflammatory cells with functions that span the continuum from innate immune responses to adaptive immunity. Activated platelets have key thromboinflammatory activities in a variety of vascular disorders and vasculopathies. Recently identified inflammatory and immune activities provide insights into the biology of these versatile blood cells that are directly relevant to human vascular diseases.
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Affiliation(s)
- Matthew T Rondina
- Department of Medicine and Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA
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140
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Lacroix R, Dubois C, Leroyer AS, Sabatier F, Dignat-George F. Revisited role of microparticles in arterial and venous thrombosis. J Thromb Haemost 2013; 11 Suppl 1:24-35. [PMID: 23809108 DOI: 10.1111/jth.12268] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Microparticles (MPs) represent a heterogeneous population of submicronic vesicles that are released in response to cell activation or apoptosis. MPs harbor a large repertoire of cell surface receptors and mRNA and biological activities representative of their parent cells and related to their involvement in many biological functions. Although MP generation is a physiological response, a dramatic increase in circulating MPs is detectable in a variety of thrombosis-associated disorders compared with healthy individuals. In this review, we will discuss a new vision of MPs as complex and ambivalent structures that express both activators and inhibitors of coagulation but also convey fibrinolytic properties. After summarizing our current knowledge about the role of MPs in venous and arterial thrombosis, this review will explore how this new vision of MPs influences their definition as emergent biomarkers in thrombotic diseases. Among the studies that have aimed to establish a link between thrombosis and MPs, a few studies have demonstrated a predictive value of MPs. So far, it is unclear whether this limited causative association is the result of current technical concerns and limited standardization or has to be integrated into a more complex vision of the role of MPs as key systems for regulating the balance between coagulation and fibrinolysis.
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Affiliation(s)
- R Lacroix
- VRCM, UMR_S1076, UFR de Pharmacie, Aix Marseille Université, INSERM, Marseille, France
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141
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Mackman N, Luther T. Platelet tissue factor: to be or not to be. Thromb Res 2013; 132:3-5. [PMID: 23731564 DOI: 10.1016/j.thromres.2013.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 05/05/2013] [Accepted: 05/07/2013] [Indexed: 10/26/2022]
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142
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Münzer P, Tolios A, Pelzl L, Schmid E, Schmidt EM, Walker B, Fröhlich H, Borst O, Gawaz M, Lang F. Thrombin-sensitive expression of the store operated Ca(2+) channel Orai1 in platelets. Biochem Biophys Res Commun 2013; 436:25-30. [PMID: 23685155 DOI: 10.1016/j.bbrc.2013.05.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 05/08/2013] [Indexed: 12/23/2022]
Abstract
Thrombin activates pore forming channel protein Orai1 resulting in store operated Ca(2+) entry (SOCE) with subsequent Ca(2+)-dependent release of platelet granules, activation of integrin αIIbβ3, adhesion, aggregation and thrombus formation. Platelets lack nuclei and are thus unable to modify protein abundance by transcriptional regulation. Nevertheless, they still contain pre-mRNA and mRNA and are thus able to express protein by stimulation of rapid translation. Platelet translation is sensitive to phosphoinositide-3-kinase (PI3K) and actin polymerization. The present study explored whether platelet activation via thrombin modifies Orai1 protein abundance. According to RT-PCR platelets contain pre-mRNA and mRNA encoding Orai1. Activation with thrombin (0.1 U/ml) results in a significant decline of pre-mRNA, which is, according to Western blotting and confocal microscopy, paralleled by a marked and statistically significant increase of Orai1 protein abundance. The increase of Orai1 protein abundance is insensitive to inhibition of transcription with actinomycin (4 μg/ml), but is significantly blunted by inhibition of translation with puromycin (100 nM) and by inhibition of PI3K with wortmannin (100 nM) or LY294002 (25 μM). In conclusion, activation of platelets stimulates the translational expression of Orai1, thus augmenting platelet Ca(2+) signaling.
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Affiliation(s)
- Patrick Münzer
- Department of Physiology, University of Tübingen, Germany
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143
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Human platelets do not express tissue factor. Thromb Res 2013; 132:112-5. [PMID: 23623171 DOI: 10.1016/j.thromres.2013.04.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/09/2013] [Accepted: 04/09/2013] [Indexed: 11/22/2022]
Abstract
BACKGROUND The controversy about the expression of tissue factor (TF) in platelet after de novo synthesis prevail despite many groups recognize that platelet isolation, assays and reagents, particularly non-specific antibodies, may account for the diversity. In this study the potential of TF expression was evaluated using immune-purified human platelets and employing a very sensitive and highly specific TF activity assay. METHODS Isolated platelets in plasma anti-coagulated with Fragmin were subjected to stimulation by LPS plus PMA, IgG antibody or TRAP and tested for TF activity. RESULTS Platelets stimulated with LPS plus PMA for 4 hours expressed trace amounts of TF like activity (PCA), not inhibited by anti-TF antibody (0.2±0.1 mU/ml blood). Platelets, not immune-adsorbed to remove monocytes, showed significant TF activity (2.0±0.9 mU/ml blood) that was nearly abolished by anti-TF antibody. IgG antibody from patient with lupus anticoagulant failed to enhance the trace amount of PCA as compared to the control in contrast to high TF activity induced in monocytes (0.4±0.1 mU/ml blood versus 27.5±10.5 mU/10(6) cells) showing that activation of complement is not mediating TF expression. Platelet subjected to TRAP activation for 10 min possessed only trace amounts of PCA that was not inhibited by anti-TF antibody and slightly enhanced by anti-TFPI antibody. CONCLUSIONS It is concluded that platelets free of monocytes do not express TF activity when stimulated by LPS or activated complement factors, implying no role for Toll like receptor (TLR4) as suggested recently. There is no evidence of TF activity associated with platelets as a result of rapid and dynamic process.
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144
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EISENREICH ANDREAS, ZAKRZEWICZ ANDREAS, HUBER KILIAN, THIERBACH HANNES, PEPKE WOJCIECH, GOLDIN-LANG PETRA, SCHULTHEISS HEINZPETER, PRIES AXEL, RAUCH URSULA. Regulation of pro-angiogenic tissue factor expression in hypoxia-induced human lung cancer cells. Oncol Rep 2013; 30:462-70. [DOI: 10.3892/or.2013.2413] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/20/2013] [Indexed: 11/05/2022] Open
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145
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Burnouf T, Goubran HA, Chen TM, Ou KL, El-Ekiaby M, Radosevic M. Blood-derived biomaterials and platelet growth factors in regenerative medicine. Blood Rev 2013; 27:77-89. [DOI: 10.1016/j.blre.2013.02.001] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Abstract
Hemostasis encompasses the tightly regulated processes of blood clotting, platelet activation, and vascular repair. After wounding, the hemostatic system engages a plethora of vascular and extravascular receptors that act in concert with blood components to seal off the damage inflicted to the vasculature and the surrounding tissue. The first important component that contributes to hemostasis is the coagulation system, while the second important component starts with platelet activation, which not only contributes to the hemostatic plug, but also accelerates the coagulation system. Eventually, coagulation and platelet activation are switched off by blood-borne inhibitors and proteolytic feedback loops. This review summarizes new concepts of activation of proteases that regulate coagulation and anticoagulation, to give rise to transient thrombin generation and fibrin clot formation. It further speculates on the (patho)physiological roles of intra- and extravascular receptors that operate in response to these proteases. Furthermore, this review provides a new framework for understanding how signaling and adhesive interactions between endothelial cells, leukocytes, and platelets can regulate thrombus formation and modulate the coagulation process. Now that the key molecular players of coagulation and platelet activation have become clear, and their complex interactions with the vessel wall have been mapped out, we can also better speculate on the causes of thrombosis-related angiopathies.
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Affiliation(s)
- Henri H. Versteeg
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Johan W. M. Heemskerk
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Marcel Levi
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Pieter H. Reitsma
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Medicine, Academic Medical Center, Amsterdam, The Netherlands
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