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Zhu Z, Luo Y, Liao H, Guo R, Hao D, Lu Z, Huang M, Sun C, Yao J, Wei N, Zeng K, Tu P, Zhang G. Icaritin Sensitizes Thrombin- and TxA2-Induced Platelet Activation and Promotes Hemostasis via Enhancing PLCγ2-PKC Signaling Pathways. Thromb Haemost 2024. [PMID: 38224965 DOI: 10.1055/a-2245-8457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
BACKGROUND Vascular injury results in uncontrollable hemorrhage in hemorrhagic diseases and excessive antithrombotic therapy. Safe and efficient hemostatic agents which can be orally administered are urgently needed. Platelets play indispensable roles in hemostasis, but there is no drug exerting hemostatic effects through enhancing platelet function. METHODS The regulatory effects of icaritin, a natural compound isolated from Herba Epimedii, on the dense granule release, thromboxane A2 (TxA2) synthesis, α-granule release, activation of integrin αIIbβ3, and aggregation of platelets induced by multiple agonists were investigated. The effects of icaritin on tail vein bleeding times of warfarin-treated mice were also evaluated. Furthermore, we investigated the underlying mechanisms by which icaritin exerted its pharmacological effects. RESULTS Icaritin alone did not activate platelets, but significantly potentiated the dense granule release, α-granule release, activation of integrin αIIbβ3, and aggregation of platelets induced by thrombin and U46619. Icaritin also shortened tail vein bleeding times of mice treated with warfarin. In addition, phosphorylated proteome analysis, immunoblotting analysis, and pharmacological research revealed that icaritin sensitized the activation of phospholipase Cγ2 (PLCγ2)-protein kinase C (PKC) signaling pathways, which play important roles in platelet activation. CONCLUSION Icaritin can sensitize platelet activation induced by thrombin and TxA2 through enhancing the activation of PLCγ2-PKC signaling pathways and promote hemostasis, and has potential to be developed into a novel orally deliverable therapeutic agent for hemorrhages.
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Affiliation(s)
- Zhixiang Zhu
- Modern Research Center for Traditional Chinese Medicine, Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Yanggan Luo
- Modern Research Center for Traditional Chinese Medicine, Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Hanjing Liao
- Modern Research Center for Traditional Chinese Medicine, Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Ran Guo
- Modern Research Center for Traditional Chinese Medicine, Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Doudou Hao
- Modern Research Center for Traditional Chinese Medicine, Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Zihan Lu
- Modern Research Center for Traditional Chinese Medicine, Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Manjing Huang
- Modern Research Center for Traditional Chinese Medicine, Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Chenghong Sun
- State Key Laboratory of Integration and Innovation of Classic Formula and Modern Chinese Medicine, Lunan Pharmaceutical Group Co. Ltd., Linyi City, Shandong Province, China
| | - Jingchun Yao
- State Key Laboratory of Integration and Innovation of Classic Formula and Modern Chinese Medicine, Lunan Pharmaceutical Group Co. Ltd., Linyi City, Shandong Province, China
| | - Ning Wei
- Department of Oncology and Cancer Therapeutics Program, Montefiore Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Kewu Zeng
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Pengfei Tu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Guimin Zhang
- State Key Laboratory of Integration and Innovation of Classic Formula and Modern Chinese Medicine, Lunan Pharmaceutical Group Co. Ltd., Linyi City, Shandong Province, China
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Kwon HW, Shin JH, Rhee MH, Park CE, Lee DH. Anti-thrombotic effects of ginsenoside Rk3 by regulating cAMP and PI3K/MAPK pathway on human platelets. J Ginseng Res 2023; 47:706-713. [PMID: 38107398 PMCID: PMC10721468 DOI: 10.1016/j.jgr.2023.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/20/2023] [Accepted: 04/20/2023] [Indexed: 12/19/2023] Open
Abstract
Background and objective The ability to inhibit aggregation has been demonstrated with synthetically derived ginsenoside compounds G-Rp (1, 3, and 4) and ginsenosides naturally found in Panax ginseng 20(S)-Rg3, Rg6, F4, and Ro. Among these compounds, Rk3 (G-Rk3) from Panax ginseng needs to be further explored in order to reveal the mechanisms of action during inhibition. Methodology Our study focused to investigate the action of G-Rk3 on agonist-stimulated human platelet aggregation, inhibition of platelet signaling molecules such as fibrinogen binding with integrin αIIbβ3 using flow cytometry, intracellular calcium mobilization, dense granule secretion, and thromboxane B2 secretion. In addition, we checked the regulation of phosphorylation on PI3K/MAPK pathway, and thrombin-induced clot retraction was also observed in platelets rich plasma. Key Results G-Rk3 significantly increased amounts of cyclic adenosine monophosphate (cAMP) and led to significant phosphorylation of cAMP-dependent kinase substrates vasodilator-stimulated phosphoprotein (VASP) and inositol 1,4,5-trisphosphate receptor (IP3R). In the presence of G-Rk3, dense tubular system Ca2+ was inhibited, and platelet activity was lowered by inactivating the integrin αIIb/β3 and reducing the binding of fibrinogen. Furthermore, the effect of G-Rk3 extended to the inhibition of MAPK and PI3K/Akt phosphorylation resulting in the reduced secretion of intracellular granules and reduced production of TXA2. Lastly, G-Rk3 inhibited platelet aggregation and thrombus formation via fibrin clot. Conclusions and implications These results suggest that when dealing with cardiovascular diseases brought upon by faulty aggregation among platelets or through the formation of a thrombus, the G-Rk3 compound can play a role as an effective prophylactic or therapeutic agent.
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Affiliation(s)
- Hyuk-Woo Kwon
- Department of Biomedical Laboratory Science, Far East University, Eumseong, Republic of Korea
| | - Jung-Hae Shin
- Department of Veterinary Medicine, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Man Hee Rhee
- Department of Veterinary Medicine, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Chang-Eun Park
- Department of Biomedical Laboratory Science, Namseoul University, Cheonan, Republic of Korea
- Molecular Diagnostics Research Institute, Namseoul University, Cheonan, Republic of Korea
| | - Dong-Ha Lee
- Department of Biomedical Laboratory Science, Namseoul University, Cheonan, Republic of Korea
- Molecular Diagnostics Research Institute, Namseoul University, Cheonan, Republic of Korea
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3
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Elgheznawy A, Öftering P, Englert M, Mott K, Kaiser F, Kusch C, Gbureck U, Bösl MR, Schulze H, Nieswandt B, Vögtle T, Hermanns HM. Loss of zinc transporters ZIP1 and ZIP3 augments platelet reactivity in response to thrombin and accelerates thrombus formation in vivo. Front Immunol 2023; 14:1197894. [PMID: 37359521 PMCID: PMC10285393 DOI: 10.3389/fimmu.2023.1197894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
Zinc (Zn2+) is considered as important mediator of immune cell function, thrombosis and haemostasis. However, our understanding of the transport mechanisms that regulate Zn2+ homeostasis in platelets is limited. Zn2+ transporters, ZIPs and ZnTs, are widely expressed in eukaryotic cells. Using mice globally lacking ZIP1 and ZIP3 (ZIP1/3 DKO), our aim was to explore the potential role of these Zn2+ transporters in maintaining platelet Zn2+ homeostasis and in the regulation of platelet function. While ICP-MS measurements indicated unaltered overall Zn2+ concentrations in platelets of ZIP1/3 DKO mice, we observed a significantly increased content of FluoZin3-stainable free Zn2+, which, however, appears to be released less efficiently upon thrombin-stimulated platelet activation. On the functional level, ZIP1/3 DKO platelets exhibited a hyperactive response towards threshold concentrations of G protein-coupled receptor (GPCR) agonists, while immunoreceptor tyrosine-based activation motif (ITAM)-coupled receptor agonist signalling was unaffected. This resulted in enhanced platelet aggregation towards thrombin, bigger thrombus volume under flow ex vivo and faster in vivo thrombus formation in ZIP1/3 DKO mice. Molecularly, augmented GPCR responses were accompanied by enhanced Ca2+ and PKC, CamKII and ERK1/2 signalling. The current study thereby identifies ZIP1 and ZIP3 as important regulators for the maintenance of platelet Zn2+ homeostasis and function.
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Affiliation(s)
- Amro Elgheznawy
- Medical Clinic II, Division of Hepatology, University Hospital Würzburg, Würzburg, Germany
| | - Patricia Öftering
- Institute of Experimental Biomedicine I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Maximilian Englert
- Institute of Experimental Biomedicine I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Kristina Mott
- Institute of Experimental Biomedicine I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Friederike Kaiser
- Department for Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Würzburg, Germany
| | - Charly Kusch
- Institute of Experimental Biomedicine I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Uwe Gbureck
- Department for Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Würzburg, Germany
| | - Michael R. Bösl
- Institute of Experimental Biomedicine I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Harald Schulze
- Institute of Experimental Biomedicine I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Bernhard Nieswandt
- Institute of Experimental Biomedicine I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Timo Vögtle
- Institute of Experimental Biomedicine I, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Heike M. Hermanns
- Medical Clinic II, Division of Hepatology, University Hospital Würzburg, Würzburg, Germany
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4
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Kerstholt M, van de Schoor FR, Oosting M, Moorlag SJCFM, Li Y, Jaeger M, van der Heijden WA, Tunjungputri RN, dos Santos JC, Kischkel B, Vrijmoeth HD, Baarsma ME, Kullberg BJ, Lupse M, Hovius JW, van den Wijngaard CC, Netea MG, de Mast Q, Joosten LAB. Identifying platelet-derived factors as amplifiers of B. burgdorferi-induced cytokine production. Clin Exp Immunol 2022; 210:53-67. [PMID: 36001729 PMCID: PMC9585555 DOI: 10.1093/cei/uxac073] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 07/07/2022] [Accepted: 08/11/2022] [Indexed: 01/25/2023] Open
Abstract
Previous studies have shown that monocytes can be 'trained' or tolerized by certain stimuli to respond stronger or weaker to a secondary stimulation. Rewiring of glucose metabolism was found to be important in inducing this phenotype. As we previously found that Borrelia burgdorferi (B. burgdorferi), the causative agent of Lyme borreliosis (LB), alters glucose metabolism in monocytes, we hypothesized that this may also induce long-term changes in innate immune responses. We found that exposure to B. burgdorferi decreased cytokine production in response to the TLR4-ligand lipopolysaccharide (LPS). In addition, B. burgdorferi exposure decreased baseline levels of glycolysis, as assessed by lactate production. Using GWAS analysis, we identified a gene, microfibril-associated protein 3-like (MFAP3L) as a factor influencing lactate production after B. burgdorferi exposure. Validation experiments proved that MFAP3L affects lactate- and cytokine production following B. burgdorferi stimulation. This is mediated by functions of MFAP3L, which includes activating ERK2 and through activation of platelet degranulation. Moreover, we showed that platelets and platelet-derived factors play important roles in B. burgdorferi-induced cytokine production. Certain platelet-derived factors, such chemokine C-X-C motif ligand 7 (CXCL7) and (C-C motif) ligand 5 (CCL5), were elevated in the circulation of LB patients in comparison to healthy individuals.
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Affiliation(s)
| | | | - Marije Oosting
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Simone J C F M Moorlag
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Yang Li
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands,Department of Computational Biology for Individualised Medicine, Centre for Individualised Infection Medicine (CiiM) and TWINCORE, Joint Ventures Between the Helmholtz-Centre for Infection Research (HZI) and the Hannover Medical School (MHH), Hannover, Germany
| | - Martin Jaeger
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wouter A van der Heijden
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rahajeng N Tunjungputri
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands,Center for Tropical and Infectious Diseases (CENTRID), Faculty of Medicine Diponegoro University, Dr. Kariadi Hospital, Semarang, Indonesia
| | - Jéssica C dos Santos
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Brenda Kischkel
- Department of Internal Medicine and Radboud Institute of Molecular Life Sciences (RIMLS), Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Hedwig D Vrijmoeth
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - M E Baarsma
- Amsterdam Institute of Infection and Immunology, Center for Experimental and Molecular Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Bart-Jan Kullberg
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mihaela Lupse
- Department of Infectious Diseases, University of Medicine and Pharmacy ‘Iuliu Hatieganu’, Cluj-Napoca, Romania
| | - Joppe W Hovius
- Amsterdam Institute of Infection and Immunology, Center for Experimental and Molecular Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Cees C van den Wijngaard
- National Institute for Public Health and the Environment (RIVM), Center of Infectious Disease Control, Bilthoven, The Netherlands
| | - Mihai G Netea
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands,Department for Immunology and Metabolism, Life and Medical Sciences Institute (LIMES), University of Bonn, Germany
| | - Quirijn de Mast
- Department of Internal Medicine and Radboudumc Center for Infectious diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Leo A B Joosten
- Correspondence: Leo A.B. Joosten, Lab Experimentele geneeskunde, Radboudumc, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands. E-mail:
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5
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Tamang HK, Yang R, Song Z, Hsu S, Peng C, Tung Y, Tzeng B, Chen C. Ca v 3.2 T-type calcium channel regulates mouse platelet activation and arterial thrombosis. J Thromb Haemost 2022; 20:1887-1899. [PMID: 35490411 PMCID: PMC9541131 DOI: 10.1111/jth.15745] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cav 3.2 is a T-type calcium channel that causes low-threshold exocytosis. T-type calcium channel blockers reduce platelet granule exocytosis and aggregation. However, studies of the T-type calcium channel in platelets are lacking. OBJECTIVE To examine the expression and role of Cav 3.2 in platelet function. METHODS Global Cav 3.2-/- and platelet-specific Cav 3.2-/- mice and littermate controls were used for this study. Western blot analysis was used to detect the presence of Cav 3.2 and activation of the calcium-responsive protein extracellular signal-regulated kinase (ERK). Fura-2 dye was used to assess platelet calcium. Flow cytometry and light transmission aggregometry were used to evaluate platelet activation markers and aggregation, respectively. FeCl3 -induced thrombosis and a microfluidic flow device were used to assess in vivo and ex vivo thrombosis, respectively. RESULTS Cav 3.2 was expressed in mouse platelets. As compared with wild-type controls, Cav 3.2-/- mouse platelets showed reduced calcium influx. Similarly, treatment with the T-type calcium channel inhibitor Ni2+ decreased the calcium influx in wild-type platelets. As compared with controls, both Cav 3.2-/- and Ni2+ -treated wild-type platelets showed reduced activation of ERK. ATP release, P-selectin exposure, and αIIb β3 activation were reduced in Cav 3.2-/- and Ni2+ -treated wild-type platelets, as was platelet aggregation. On in vivo and ex vivo thrombosis assay, Cav3.2 deletion caused delayed thrombus formation. However, tail bleeding assay showed intact hemostasis. CONCLUSION These results suggest that Cav 3.2 is required for the optimal activation of platelets.
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Affiliation(s)
- Hem Kumar Tamang
- Taiwan International Graduate Program in Molecular MedicineNational Yang Ming Chiao Tung University and Academia SinicaTaipeiTaiwan
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
| | - Ruey‐Bing Yang
- Taiwan International Graduate Program in Molecular MedicineNational Yang Ming Chiao Tung University and Academia SinicaTaipeiTaiwan
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
| | - Zong‐Han Song
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
| | - Shao‐Chun Hsu
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
| | | | - Yi‐Chung Tung
- Research Center for Applied SciencesAcademia SinicaTaipeiTaiwan
| | - Bing‐Hsiean Tzeng
- Division of CardiologyFar Eastern Memorial Hospital and Tri‐Service General HospitalNational Defense Medical CenterTaipeiTaiwan
| | - Chien‐Chang Chen
- Taiwan International Graduate Program in Molecular MedicineNational Yang Ming Chiao Tung University and Academia SinicaTaipeiTaiwan
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
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6
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Yoon SS, Kwon HW, Shin JH, Rhee MH, Park CE, Lee DH. Anti-Thrombotic Effects of Artesunate through Regulation of cAMP and PI3K/MAPK Pathway on Human Platelets. Int J Mol Sci 2022; 23:ijms23031586. [PMID: 35163507 PMCID: PMC8836205 DOI: 10.3390/ijms23031586] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 12/29/2022] Open
Abstract
Normal activation of platelets and their aggregation are crucial for proper hemostasis. It appears that excessive or abnormal aggregation of platelets may bring about cardiovascular diseases such as stroke, atherosclerosis, and thrombosis. For this reason, finding a substance that can regulate platelet aggregation or suppress aggregation will aid in the prevention and treatment of cardiovascular diseases. Artesunate is a compound extracted from the plant roots of Artemisia or Scopolia, and its effects have shown to be promising in areas of anticancer and Alzheimer’s disease. However, the role and mechanisms by which artesunate affects the aggregation of platelets and the formation of a thrombus are currently not understood. This study examines the ways artesunate affects the aggregation of platelets and the formation of a thrombus on platelets induced by U46619. As a result, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) production were increased significantly by artesunate relative to the doses, as well as phosphorylated vasodilator-stimulated phosphoprotein (VASP) and inositol 1,4,5-trisphosphate receptor (IP3R), substrates to cAMP-dependent kinase and cGMP-dependent kinase, in a significant manner. The Ca2+, normally mobilized from the dense tubular system, was inhibited due to IP3R phosphorylation from artesunate, and phosphorylated VASP aided in inhibiting platelet activity via αIIb/β3 platelet membrane inactivation and inhibiting fibrinogen binding. In addition, MAPK and PI3K/Akt phosphorylation was inhibited via artesunate in a significant manner, causing the production of TXA2 and intracellular granular secretion (serotonin and ATP release) to be reduced. Therefore, we suggest that artesunate has value as a substance that inhibits platelet aggregation and thrombus formation through an antiplatelet mechanism.
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Affiliation(s)
- Shin-Sook Yoon
- Department of Biomedical Laboratory Science, Namseoul University, Cheonan 31020, Korea; (S.-S.Y.); (C.-E.P.)
| | - Hyuk-Woo Kwon
- Department of Biomedical Laboratory Science, Far East University, Eumseong 27601, Korea;
| | - Jung-Hae Shin
- Department of Veterinary Medicine, College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea; (J.-H.S.); (M.H.R.)
| | - Man Hee Rhee
- Department of Veterinary Medicine, College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea; (J.-H.S.); (M.H.R.)
| | - Chang-Eun Park
- Department of Biomedical Laboratory Science, Namseoul University, Cheonan 31020, Korea; (S.-S.Y.); (C.-E.P.)
- Molecular Diagnostics Research Institute, Namseoul University, Cheonan 31020, Korea
| | - Dong-Ha Lee
- Department of Biomedical Laboratory Science, Namseoul University, Cheonan 31020, Korea; (S.-S.Y.); (C.-E.P.)
- Molecular Diagnostics Research Institute, Namseoul University, Cheonan 31020, Korea
- Correspondence:
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7
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Abstract
Until recently, the nucleic acid content of platelets was considered to be fully determined by their progenitor megakaryocyte. However, it is now well understood that additional mediators (eg, cancer cells) can intervene, thereby influencing the RNA repertoire of platelets. Platelets are highly dynamic cells that are able to communicate and influence their environment. For instance, platelets have been involved in various steps of cancer development and progression by supporting tumor growth, survival, and dissemination. Cancer cells can directly and/or indirectly influence platelet RNA content, resulting in tumor-mediated "education" of platelets. Alterations in the tumor-educated platelet RNA profile have been described as a novel source of potential biomarkers. Individual platelet RNA biomarkers as well as complex RNA signatures may be used for early detection of cancer and treatment monitoring. Here, we review the RNA transfer occurring between cancer cells and platelets. We explore the potential use of platelet RNA biomarkers as a liquid biopsy biosource and discuss methods to evaluate the transcriptomic content of platelets.
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8
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Nam GS, Park HJ, Nam KS. The antithrombotic effect of caffeic acid is associated with a cAMP-dependent pathway and clot retraction in human platelets. Thromb Res 2020; 195:87-94. [DOI: 10.1016/j.thromres.2020.07.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/25/2020] [Accepted: 07/08/2020] [Indexed: 10/23/2022]
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9
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Patel P, Naik UP. Platelet MAPKs-a 20+ year history: What do we really know? J Thromb Haemost 2020; 18:2087-2102. [PMID: 32574399 DOI: 10.1111/jth.14967] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 01/01/2023]
Abstract
The existence of mitogen activated protein kinases (MAPKs) in platelets has been known for more than 20 years. Since that time hundreds of reports have been published describing the conditions that cause MAPK activation in platelets and their role in regulating diverse platelet functions from the molecular to physiological level. However, this cacophony of reports, with inconsistent and sometimes contradictory findings, has muddied the waters leading to great confusion. Since the last review of platelet MAPKs was published more than a decade ago, there have been more than 50 reports, including the description of novel knockout mouse models, that have furthered our knowledge. Therefore, we undertook an extensive literature review to delineate what is known about platelet MAPKs. We specifically discuss what is currently known about how MAPKs are activated and what signaling cascades they regulate in platelets incorporating recent findings from knockout mouse models. In addition, we will discuss the role each MAPK plays in regulating distinct platelet functions. In doing so, we hope to clarify the role for MAPKs and identify knowledge gaps in this field that await future researchers. In addition, we discuss the limitations of current studies with a particular focus on the off-target effects of commonly used MAPK inhibitors. We conclude with a look at the clinical utility of MAPK inhibitors as potential antithrombotic therapies with an analysis of current clinical trial data.
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Affiliation(s)
- Pravin Patel
- Department of Medicine, Cardeza Center for Hemostasis, Thrombosis, and Vascular Biology, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA, USA
| | - Ulhas P Naik
- Department of Medicine, Cardeza Center for Hemostasis, Thrombosis, and Vascular Biology, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA, USA
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10
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Gutiérrez-Herrero S, Fernández-Infante C, Hernández-Cano L, Ortiz-Rivero S, Guijas C, Martín-Granado V, González-Porras JR, Balsinde J, Porras A, Guerrero C. C3G contributes to platelet activation and aggregation by regulating major signaling pathways. Signal Transduct Target Ther 2020; 5:29. [PMID: 32296045 PMCID: PMC7109025 DOI: 10.1038/s41392-020-0119-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 01/17/2020] [Accepted: 01/18/2020] [Indexed: 01/25/2023] Open
Abstract
C3G is a GEF (guanine nucleotide exchange factor) for Rap GTPases, among which the isoform Rap1b is an essential protein in platelet biology. Using transgenic mouse models with platelet-specific overexpression of C3G or mutant C3GΔCat, we have unveiled a new function of C3G in regulating the hemostatic function of platelets through its participation in the thrombin-PKC-Rap1b pathway. C3G also plays important roles in angiogenesis, tumor growth, and metastasis through its regulation of the platelet secretome. In addition, C3G contributes to megakaryopoiesis and thrombopoiesis. Here, we used a platelet-specific C3G-KO mouse model to further support the role of C3G in hemostasis. C3G-KO platelets showed a significant delay in platelet activation and aggregation as a consequence of the defective activation of Rap1, which resulted in decreased thrombus formation in vivo. Additionally, we explored the contribution of C3G-Rap1b to platelet signaling pathways triggered by thrombin, PMA or ADP, in the referenced transgenic mouse model, through the use of a battery of specific inhibitors. We found that platelet C3G is phosphorylated at Tyr504 by a mechanism involving PKC-Src. This phosphorylation was shown to be positively regulated by ERKs through their inhibition of the tyrosine phosphatase Shp2. Moreover, C3G participates in the ADP-P2Y12-PI3K-Rap1b pathway and is a mediator of thrombin-TXA2 activities. However, it inhibits the synthesis of TXA2 through cPLA2 regulation. Taken together, our data reveal the critical role of C3G in the main pathways leading to platelet activation and aggregation through the regulation of Rap1b.
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Affiliation(s)
- Sara Gutiérrez-Herrero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
| | - Cristina Fernández-Infante
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Luis Hernández-Cano
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Sara Ortiz-Rivero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
| | - Carlos Guijas
- Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC), University of Valladolid, Valladolid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Víctor Martín-Granado
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
| | - José Ramón González-Porras
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
- Departamento de Hematología, Hospital Universitario de Salamanca (HUS), Salamanca, Spain
| | - Jesús Balsinde
- Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC), University of Valladolid, Valladolid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Almudena Porras
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Complutense University of Madrid. Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.
| | - Carmen Guerrero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain.
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain.
- Departamento de Medicina, University of Salamanca, Salamanca, Spain.
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11
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Kim S, Kim YE, Hong S, Kim KT, Sung DK, Lee Y, Park WS, Chang YS, Song MR. Reactive microglia and astrocytes in neonatal intraventricular hemorrhage model are blocked by mesenchymal stem cells. Glia 2019; 68:178-192. [PMID: 31441125 DOI: 10.1002/glia.23712] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 07/08/2019] [Accepted: 08/01/2019] [Indexed: 12/12/2022]
Abstract
Severe intraventricular hemorrhage (IVH) in premature infants triggers reactive gliosis, causing acute neuronal death and glial scar formation. Transplantation of mesenchymal stem cells (MSCs) has often showed improved CNS recovery in an IVH model, but whether this response is related to reactive glial cells is still unclear. Herein, we suggest that MSCs impede the response of reactive microglia rather than astrocytes, thereby blocking neuronal damage. Astrocytes alone showed mild reactiveness under hemorrhagic conditions mimicked by thrombin treatment, and this was not blocked by MSC-conditioned medium (MSC-CM) in vitro. In contrast, thrombin-induced microglial activation and release of proinflammatory cytokines were inhibited by MSC-CM. Interestingly, astrocytes showed greater reactive response when co-cultured with microglia, and this was abolished in the presence of MSC-CM. Gene expression profiles in microglia revealed that transcript levels of genes for immune response and proinflammatory cytokines were altered by thrombin treatment. This result coincided with the robust phosphorylation of STAT1 and p38 MAPK, which might be responsible for the production and release of proinflammatory cytokines. Furthermore, application of MSC-CM diminished thrombin-mediated phosphorylation of STAT1 and p38 MAPK, supporting the acute anti-inflammatory role of MSCs under hemorrhagic conditions. In line with this, activation of microglia and consequent cytokine release were impaired in Stat1-null mice. However, reactive response in Stat1-deficient astrocytes was maintained. Taken together, our results demonstrate that MSCs mainly block the activation of microglia involving STAT1-mediated cytokine release and subsequent reduction of reactive astrocytes.
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Affiliation(s)
- Seojeong Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Young Eun Kim
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.,Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Sungkyunkwan University, Seoul, Republic of Korea
| | - Sujeong Hong
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Kyung-Tai Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Dong Kyung Sung
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Yunjeong Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Won Soon Park
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Yun Sil Chang
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.,Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Sungkyunkwan University, Seoul, Republic of Korea
| | - Mi-Ryoung Song
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
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12
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Inamdar VV, Reddy H, Dangelmaier C, Kostyak JC, Kunapuli SP. The protein tyrosine phosphatase PTPN7 is a negative regulator of ERK activation and thromboxane generation in platelets. J Biol Chem 2019; 294:12547-12554. [PMID: 31266805 DOI: 10.1074/jbc.ra119.007735] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 06/20/2019] [Indexed: 11/06/2022] Open
Abstract
Protein tyrosine phosphatase nonreceptor type 7 (PTPN7), also called hematopoietic protein tyrosine phosphatase, controls extracellular signal-regulated protein kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase in T lymphocytes. Because ERK1/2 plays an important role in regulating thromboxane A2 (TXA2) generation in platelets, we investigated the function of PTPN7 in these cells. Using immunoblot analysis, we detected PTPN7 in both human and mouse platelets but not in PTPN7-null mice. PTPN7 KO mouse platelets exhibited increased platelet functional responses, including aggregation, dense granule secretion, and TXA2 generation, compared with platelets from WT littermates, upon stimulation with both G protein-coupled receptor (GPCR) and glycoprotein VI (GPVI) agonists. Using the GPCR agonist AYPGKF in the presence of the COX inhibitor indomethacin, we found that PTPN7 KO mouse platelets aggregated and secreted to the same extent as WT platelets, suggesting that elevated TXA2 is responsible for the potentiation of platelet functional responses in PTPN7-KO platelets. Phosphorylation of ERK1/2 was also elevated in PTPN7 KO platelets. Stimulation of platelets with the GPVI agonist collagen-related peptide along with the COX inhibitor indomethacin did not result in phosphorylation of ERK1/2, indicating that GPVI-mediated ERK phosphorylation occurs through TXA2 Although bleeding times did not significantly differ between PTPN7-null and WT mice, time to death was significantly faster in PTPN7-null mice than in WT mice in a pulmonary thromboembolism model. We conclude that PTPN7 regulates platelet functional responses downstream of GPCR agonists, but not GPVI agonists, through inhibition of ERK activation and thromboxane generation.
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Affiliation(s)
- Vaishali V Inamdar
- Sol Sherry Thrombosis Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140
| | - Haritha Reddy
- Sol Sherry Thrombosis Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140
| | - Carol Dangelmaier
- Sol Sherry Thrombosis Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140
| | - John C Kostyak
- Sol Sherry Thrombosis Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140
| | - Satya P Kunapuli
- Sol Sherry Thrombosis Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140.
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13
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Platelet MEKK3 regulates arterial thrombosis and myocardial infarct expansion in mice. Blood Adv 2019; 2:1439-1448. [PMID: 29941457 DOI: 10.1182/bloodadvances.2017015149] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 05/20/2018] [Indexed: 12/25/2022] Open
Abstract
MAPKs play important roles in platelet activation. However, the molecular mechanisms by which MAPKs are regulated in platelets remain largely unknown. Real-time polymerase chain reaction and western blot data showed that MEKK3, a key MAP3K family member, was expressed in human and mouse platelets. Then, megakaryocyte/platelet-specific MEKK3-deletion (MEKK3-/- ) mice were developed to elucidate the platelet-related function(s) of MEKK3. We found that agonist-induced aggregation and degranulation were reduced in MEKK3-/- platelets in vitro. MEKK3 deficiency significantly impaired integrin αIIbβ3-mediated inside-out signaling but did not affect the outside-in signaling. At the molecular level, MEKK3 deficiency led to severely impaired activation of extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun NH2-terminal kinase 2 but not p38 or ERK5. In vivo, MEKK3-/- mice showed delayed thrombus formation following FeCl3-induced carotid artery injury. Interestingly, the tail bleeding time was normal in MEKK3-/- mice. Moreover, MEKK3-/- mice had fewer microthrombi, reduced myocardial infarction (MI) size, and improved post-MI heart function in a mouse model of MI. These results suggest that MEKK3 plays important roles in platelet MAPK activation and may be used as a new effective target for antithrombosis and prevention of MI expansion.
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14
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Abstract
Liquid biopsies have been considered the holy grail in achieving effective cancer management, with blood tests offering a minimally invasive, safe, and sensitive alternative or complementary approach for tissue biopsies. Currently, blood-based liquid biopsy measurements focus on the evaluation of biomarker types, including circulating tumor DNA, circulating tumor cells, extracellular vesicles (exosomes and oncosomes), and tumor-educated platelets (TEPs). Despite the potential of individual techniques, each has its own advantages and disadvantages. Here, we provide further insight into TEPs.
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15
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Liao W, Ma X, Li J, Li X, Guo Z, Zhou S, Sun H. A review of the mechanism of action of Dantonic® for the treatment of chronic stable angina. Biomed Pharmacother 2019; 109:690-700. [DOI: 10.1016/j.biopha.2018.10.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/30/2018] [Accepted: 10/03/2018] [Indexed: 01/04/2023] Open
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16
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Unsworth AJ, Bye AP, Kriek N, Sage T, Osborne AA, Donaghy D, Gibbins JM. Cobimetinib and trametinib inhibit platelet MEK but do not cause platelet dysfunction. Platelets 2018; 30:762-772. [PMID: 30252580 PMCID: PMC6594423 DOI: 10.1080/09537104.2018.1514107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The MEK inhibitors cobimetinib and trametinib are used in combination with BRAF inhibitors to treat metastatic melanoma but increase rates of hemorrhage relative to BRAF inhibitors alone. Platelets express several members of the MAPK signalling cascade including MEK1 and MEK2 and ERK1 and ERK2 but their role in platelet function and haemostasis is ambiguous as previous reports have been contradictory. It is therefore unclear if MEK inhibitors might be causing platelet dysfunction and contributing to increased hemorrhage. In the present study we performed pharmacological characterisation of cobimetinib and trametinib in vitro to investigate potential for MEK inhibitors to cause platelet dysfunction. We report that whilst both cobimetinib and trametinib are potent inhibitors of platelet MEK activity, treatment with trametinib did not alter platelet function. Treatment with cobimetinib results in inhibition of platelet aggregation, integrin activation, alpha-granule secretion and adhesion but only at suprapharmacological concentrations. We identified that the inhibitory effects of high concentrations of cobimetinib are associated with off-target inhibition on Akt and PKC. Neither inhibitor caused any alteration in thrombus formation on collagen under flow conditions in vitro. Our findings demonstrate that platelets are able to function normally when MEK activity is fully inhibited, indicating MEK activity is dispensable for normal platelet function. We conclude that the MEK inhibitors cobimetinib and trametinib do not induce platelet dysfunction and are therefore unlikely to contribute to increased incidence of bleeding reported during MEK inhibitor therapy.
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Affiliation(s)
- Amanda J Unsworth
- a Institute for Cardiovascular and Metabolic Research , University of Reading, School of Biological Sciences , Reading , UK
| | - Alexander P Bye
- a Institute for Cardiovascular and Metabolic Research , University of Reading, School of Biological Sciences , Reading , UK
| | - Neline Kriek
- a Institute for Cardiovascular and Metabolic Research , University of Reading, School of Biological Sciences , Reading , UK
| | - Tanya Sage
- a Institute for Cardiovascular and Metabolic Research , University of Reading, School of Biological Sciences , Reading , UK
| | - Ashley A Osborne
- a Institute for Cardiovascular and Metabolic Research , University of Reading, School of Biological Sciences , Reading , UK
| | - Dillon Donaghy
- b Department of Microbiology Immunology and Pathology , Colorado State University , Fort Collins , CO , USA
| | - Jonathan M Gibbins
- a Institute for Cardiovascular and Metabolic Research , University of Reading, School of Biological Sciences , Reading , UK
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17
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Bekeschus S, Brüggemeier J, Hackbarth C, Weltmann KD, von Woedtke T, Partecke LI, van der Linde J. The feed gas composition determines the degree of physical plasma-induced platelet activation for blood coagulation. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/1361-6595/aaaf0e] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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18
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Shin JH, Kwon HW, Rhee MH, Park HJ. Inhibitory effects of thromboxane A 2 generation by ginsenoside Ro due to attenuation of cytosolic phospholipase A 2 phosphorylation and arachidonic acid release. J Ginseng Res 2018; 43:236-241. [PMID: 30976161 PMCID: PMC6437639 DOI: 10.1016/j.jgr.2017.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 12/04/2017] [Accepted: 12/12/2017] [Indexed: 12/19/2022] Open
Abstract
Background Thromboxane A2 (TXA2) induces platelet aggregation and promotes thrombus formation. Although ginsenoside Ro (G-Ro) from Panax ginseng is known to exhibit a Ca2+-antagonistic antiplatelet effect, whether it inhibits Ca2+-dependent cytosolic phospholipase A2 (cPLA2α) activity to prevent the release of arachidonic acid (AA), a TXA2 precursor, is unknown. In this study, we attempted to identify the mechanism underlying G-Ro-mediated TXA2 inhibition. Methods We investigated whether G-Ro attenuates TXA2 production and its associated molecules, such as cyclooxygenase-1 (COX-1), TXA2 synthase (TXAS), cPLA2α, mitogen-activated protein kinases, and AA. To assay COX-1 and TXAS, we used microsomal fraction of platelets. Results G-Ro reduced TXA2 production by inhibiting AA release. It acted by decreasing the phosphorylation of cPLA2α, p38-mitogen-activated protein kinase, and c-Jun N-terminal kinase1, rather than by inhibiting COX-1 and TXAS in thrombin-activated human platelets. Conclusion G-Ro inhibits AA release to attenuate TXA2 production, which may counteract TXA2-associated thrombosis.
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Affiliation(s)
- Jung-Hae Shin
- Department of Biomedical Laboratory Science, College of Biomedical Science and Engineering, Inje University, Gimhae, Republic of Korea
| | - Hyuk-Woo Kwon
- Department of Biomedical Laboratory Science, Far East University, Eumseong, Republic of Korea
| | - Man Hee Rhee
- Laboratory of Veterinary Physiology and Signaling, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Hwa-Jin Park
- Department of Biomedical Laboratory Science, College of Biomedical Science and Engineering, Inje University, Gimhae, Republic of Korea
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19
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Tatour M, Shapira M, Axelman E, Ghanem S, Keren-Politansky A, Bonstein L, Brenner B, Nadir Y. Thrombin is a selective inducer of heparanase release from platelets and granulocytes via protease-activated receptor-1. Thromb Haemost 2017; 117:1391-1401. [DOI: 10.1160/th16-10-0766] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 04/09/2017] [Indexed: 12/23/2022]
Abstract
SummaryHeparanase, known to be involved in angiogenesis and metastasis, was shown to form a complex with tissue factor (TF) and to enhance the generation of factor Xa. Platelets and granulocytes contain abundant amounts of heparanase that may enhance the coagulation system upon discharge. It was the aim of this study to identify the inducer and pathway of heparanase release from these cells. Platelets and granulocytes were purified from pooled normal plasma and were incubated with ATP, ADP, epinephrine, collagen, ristocetin, arachidonic acid, serotonin, LPS and thrombin. Heparanase levels were assessed by ELISA, heparanase procoagulant activity assay and western blot analysis. The effects of selective protease-activated receptor (PAR)-1 and 2 inhibitors and PAR-1 and 4 activators were studied. An in-house synthesised inhibitory peptide to heparanase was used to evaluate platelet heparanase involvement in activation of the coagulation system. Heparanase was released from platelets only by thrombin induction while other inducers exerted no such effect. The heparanase level in a platelet was found to be 40 % higher than in a granulocyte. Heparanase released from platelets or granulocytes increased factor Xa generation by three-fold. PAR-1 activation via ERK intracellular pathway was found to induce heparanase release. In conclusion, heparanase is selectively released from platelets and granulocytes by thrombin interacting with PAR-1. Heparanase derived from platelets and granulocytes is involved in activation of the extrinsic coagulation pathway. The present study implies on a potential anticoagulant effect, in addition to anti-platelet effect, of the new clinically studied PAR-1 inhibitors.
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20
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Ask1 regulates murine platelet granule secretion, thromboxane A 2 generation, and thrombus formation. Blood 2016; 129:1197-1209. [PMID: 28028021 DOI: 10.1182/blood-2016-07-729780] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 12/12/2016] [Indexed: 12/26/2022] Open
Abstract
Mitogen-activated protein kinases (MAPKs) are expressed in platelets and are activated downstream of physiological agonists. Pharmacological and genetic evidence indicate that MAPKs play a significant role in hemostasis and thrombosis, but it is not well understood how MAPKs are activated upon platelet stimulation. Here, we show that apoptosis signal-regulating kinase 1 (ASK1), a member of the MAP3K family, is expressed in both human and murine platelets. ASK1 is rapidly and robustly activated upon platelet stimulation by physiological agonists. Disruption of Ask1 (Ask1-/- ) resulted in a marked functional defect in platelets. Ask1-/- platelets showed an impaired agonist-induced integrin αIIbβ3 activation and platelet aggregation. Although there was no difference in Ca2+ rise, platelet granule secretion and thromboxane A2 (TxA2) generation were significantly attenuated in Ask1-/- platelets. The defective granule secretion observed in Ask1-/- platelets was a consequence of impaired TxA2 generation. Biochemical studies showed that platelet agonists failed to activate p38 MAPK in Ask1-/- platelets. On the contrary, activation of c-Jun N-terminal kinases and extracellular signal-regulated kinase 1/2 MAPKs was augmented in Ask1-/- platelets. The defect in p38 MAPK results in failed phosphorylation of cPLA2 in Ask1-/- platelets and impaired platelet aggregate formation under flow. The absence of Ask1 renders mice defective in hemostasis as assessed by prolonged tail-bleeding times. Deletion of Ask1 also reduces thrombosis as assessed by delayed vessel occlusion of carotid artery after FeCl3-induced injury and protects against collagen/epinephrine-induced pulmonary thromboembolism. These results suggest that the platelet Ask1 plays an important role in regulation of hemostasis and thrombosis.
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21
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Pellerin D, Çaku A, Fradet M, Bouvier P, Dubé J, Corbin F. Lovastatin corrects ERK pathway hyperactivation in fragile X syndrome: potential of platelet’s signaling cascades as new outcome measures in clinical trials. Biomarkers 2016; 21:497-508. [DOI: 10.3109/1354750x.2016.1160289] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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22
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Karim ZA, Alshbool FZ, Vemana HP, Conlon C, Druey KM, Khasawneh FT. CXCL12 regulates platelet activation via the regulator of G-protein signaling 16. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1863:314-21. [PMID: 26628381 PMCID: PMC10983798 DOI: 10.1016/j.bbamcr.2015.11.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/27/2015] [Accepted: 11/24/2015] [Indexed: 01/17/2023]
Abstract
The regulators of G protein signaling (RGS) protein superfamily negatively controls G protein-coupled receptor signal transduction pathways. One of the members of this family, RGS16, is highly expressed in megakaryocytes and platelets. Studies of its function in platelet and megakaryocyte biology have been limited, in part, due to lack of pharmacological inhibitors. For example, RGS16 overexpression inhibited CXC chemokine receptor 4 (CXCR4)-mediated megakaryocyte migration. More recent studies showed that the chemokine stromal cell-derived factor (SDF1α or CXCL12) regulates platelet function via CXCR4. Based on these considerations, the present study investigated the capacity of RGS16 to regulate CXCL12-dependent platelet function, using the RGS16 knockout mouse model (Rgs16(-/-)). RGS16-deficient platelets had increased protease activated receptor 4 and collagen-induced aggregation, as well as increased CXCL12-dependent agonist-induced aggregation, dense and alpha granule secretion, integrin αIIbβ3 activation and phosphatidylserine exposure compared to those from WT littermates. CXCL12 alone did not stimulate aggregation or secretion in either RGS16-deficient or WT platelets. Furthermore, platelets from Rgs16(-/-) mice displayed enhanced phosphorylation of ERK and Akt following CXCL12 stimulation relative to controls. Finally, we also found that PKCδ is involved in regulating CXCL12-dependent activation of ERK and Akt, in the Rgs16-deficient platelets. Collectively, our findings provide the first evidence that RGS16 plays an important role in platelet function by modulating CXCL12-dependent platelet activation.
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Affiliation(s)
- Zubair A Karim
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Fatima Z Alshbool
- Department of Pharmacology, Loma Linda University, Loma Linda, CA 92354, USA
| | - Hari Priya Vemana
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Christine Conlon
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Kirk M Druey
- Molecular Signal Transduction Section, Laboratory of Allergic Diseases, NIAID/NIH, 50 South Drive Room 4154, Bethesda, MD 20892, USA
| | - Fadi T Khasawneh
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA 91766, USA.
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23
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Kim SD, Lee YJ, Baik JS, Han JY, Lee CG, Heo K, Park YS, Kim JS, Ji HD, Park SI, Rhee MH, Yang K. Baicalein inhibits agonist- and tumor cell-induced platelet aggregation while suppressing pulmonary tumor metastasis via cAMP-mediated VASP phosphorylation along with impaired MAPKs and PI3K-Akt activation. Biochem Pharmacol 2014; 92:251-65. [PMID: 25268843 DOI: 10.1016/j.bcp.2014.09.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/20/2014] [Accepted: 09/22/2014] [Indexed: 01/09/2023]
Abstract
Recently, the importance of platelet activation in cancer metastasis has become generally accepted. As a result, the development of new platelet inhibitors with minimal adverse effects is now a promising area of targeted cancer therapy. Baicalein is a functional ingredient derived from the root of Scutellaria baicalensis Georgi, a plant used intraditional medicine. The pharmacological effects of this compound including anti-oxidative and anti-inflammatory activities have already been demonstrated. However, its effects on platelet activation are unknown. We therefore investigated the effects of baicalein on ligand-induced platelet aggregation and pulmonary cancer metastasis. In the present study, baicalein inhibited agonist-induced platelet aggregation, granule secretion markers (P-selectin expression and ATP release), [Ca(2+)]i mobilization, and integrin αIIbβ3 expression. Additionally, baicalein attenuated ERK2, p38, and Akt activation, and enhanced VASP phosphorylation. Indeed, baicalein was shown to directly inhibit PI3K kinase activity. Moreover, baicalein attenuated the platelet aggregation induced by C6 rat glioma tumor cells in vitro and suppressed CT26 colon cancer metastasis in mice. These features indicate that baicalein is a potential therapeutic drug for the prevention of cancer metastasis.
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Affiliation(s)
- Sung Dae Kim
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea
| | - Young Ji Lee
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea
| | - Ji Sue Baik
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea
| | - Joeng Yoon Han
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea
| | - Chang Geun Lee
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea
| | - Kyu Heo
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea
| | - You Soo Park
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea
| | - Joong Sun Kim
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea
| | - Hyun Dong Ji
- Laboratory of Veterinary Physiology and Cell Signaling, College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Se Il Park
- Cardiovascular Product Evaluation Center, College of Medicine, Yonsei University, Seoul 120-752, Republic of Korea
| | - Man Hee Rhee
- Laboratory of Veterinary Physiology and Cell Signaling, College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Republic of Korea.
| | - Kwangmo Yang
- Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea; Department of Radiation Oncology, Dongnam Institute of Radiological and Medical Sciences, Busan 619-953, Republic of Korea; Department of Radiaton Oncology, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Republic of Korea.
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Moore SF, Hunter RW, Hers I. Protein kinase C and P2Y12 take center stage in thrombin-mediated activation of mammalian target of rapamycin complex 1 in human platelets. J Thromb Haemost 2014; 12:748-60. [PMID: 24612393 PMCID: PMC4238809 DOI: 10.1111/jth.12552] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 02/25/2014] [Indexed: 01/24/2023]
Abstract
BACKGROUND Rapamycin, an inhibitor of mammalian target of rapamycin complex-1 (mTORC1), reduces platelet spreading, thrombus stability, and clot retraction. Despite an important role of mTORC1 in platelet function, little is known about how it is regulated. The objective of this study was to determine the signaling pathways that regulate mTORC1 in human platelets. METHODS Mammalian target of rapamycin complex-1 activation was assessed by measuring the phosphorylation of its downstream substrate ribosomal S6 kinase 1 (p70S6K). RESULTS Thrombin or the protein kinase C (PKC) activator phorbal 12-myristate 13-acetate stimulated activation of mTORC1 in a PKC-dependent, Akt-independent manner that correlated with phosphorylation of tuberin/tuberous sclerosis 2 (TSC2) (Ser939 and Thr1462). In contrast, insulin-like growth factor 1 (IGF-1)-stimulated TSC2 phosphorylation was completely dependent on phosphoinositide 3 kinase (PI3 kinase)/Akt but did not result in any detectable mTORC1 activation. Early (Ser939 and Thr1462) and late (Thr1462) TSC2 phosphorylation in response to thrombin were directly PKC dependent, whereas later TSC2 (Ser939) and p70S6K phosphorylation were largely dependent on paracrine signaling through P2Y(12). PKC-mediated adenosine diphosphate (ADP) secretion was essential for thrombin-stimulated mTORC1 activation, as (i) ADP rescued p70S6K phosphorylation in the presence of a PKC inhibitor and (ii) P2Y(12) antagonism prevented thrombin-mediated mTORC1 activation. Rescue of mTORC1 activation with exogenous ADP was completely dependent on the Src family kinases but independent of PI3 kinase/Akt. Interestingly, although inhibition of Src blocked the ADP rescue, it had little effect on thrombin-stimulated p70S6K phosphorylation under conditions where PKC was not inhibited. CONCLUSION These results demonstrate that thrombin activates the mTORC1 pathway in human platelets through PKC-mediated ADP secretion and subsequent activation of P2Y(12), in a manner largely independent of the canonical PI3 kinase/Akt pathway.
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Affiliation(s)
- S F Moore
- School of Physiology and Pharmacology, Medical Sciences Building, University of Bristol, Bristol, UK
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Zhou Q, Jiang L, Xu C, Luo D, Zeng C, Liu P, Yue M, Liu Y, Hu X, Hu H. Ginsenoside Rg1 inhibits platelet activation and arterial thrombosis. Thromb Res 2013; 133:57-65. [PMID: 24196231 DOI: 10.1016/j.thromres.2013.10.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 10/19/2013] [Accepted: 10/20/2013] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Derived from the root of Panax ginseng C.A.Mey, Panax notoginsenosides (PNS) is a widely used herbal medicine to treat atherothrombotic diseases in Asian medicine. Ginsenoside Rg1 is one of the main compounds responsible for the pharmaceutical actions of PNS. As platelets play pivotal roles in atherothrombogenesis, we therefore studied the effect of Rg1 on platelet activation and its underlying mechanisms. MATERIALS AND METHODS Human platelets are obtained from healthy subjects. Platelet activation and the inhibition of Rg1 were assessed by Born aggregometer, flow cytmetry, flow chamber and western blot. The in vivo thrombosis model was induced by 10% FeCl3 on mesenteric arterioles of wild type B57/b6 mice. RESULTS Rg1 significantly inhibited platelet aggregation induced by thrombin, ADP, collagen and U46619, e.g., aggregation rate stimulated by 0.1UmL(-1) thrombin was decreased 46% by Rg1. Rg1 also reduced thrombin (0.1UmL(-1))-enhanced fibrinogen binding and P-selectin expression of single platelet by 81% and 66%, respectively. Rg1 affected αIIbβ3-mediated outside-in signaling as demonstrated by diminished platelet spreading on immobilized fibrinogen. Rg1 also decreased the rate of clot retraction in platelet rich plasma. Furthermore, Rg1 decreased platelet adhesion on collagen surface under a shear rate correlated to the arterial flow (1000s(-1)) by approximately 70%. Western blot showed that Rg1 potently inhibited ERK phosphrylation. The in vitro findings were further evaluated in the mouse model of in vivo arterial thrombosis, and Rg1 was found to prolong the mesenteric arterial occlusion time (34.9±4.1min without and 64.3±4.9min with Rg1; p<0.01). CONCLUSIONS Rg1 inhibits platelet activation via the inhibition of ERK pathway, and attenuates arterial thrombus formation in vivo.
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Affiliation(s)
- Qi Zhou
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Lei Jiang
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Chunhua Xu
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Dongjiao Luo
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Chunlai Zeng
- Department of Cardiology, Lishui Central Hospital, Lishui, China
| | - Pu Liu
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Ming Yue
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yangyang Liu
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaosheng Hu
- Department of Cardiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Hu Hu
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China.
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Bonilla L, O‘Donnell V, Clark S, Rubbo H, Trostchansky A. Regulation of protein kinase C by nitroarachidonic acid: Impact on human platelet activation. Arch Biochem Biophys 2013; 533:55-61. [DOI: 10.1016/j.abb.2013.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/28/2013] [Accepted: 03/02/2013] [Indexed: 11/17/2022]
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Yeung J, Apopa PL, Vesci J, Kenyon V, Rai G, Jadhav A, Simeonov A, Holman TR, Maloney DJ, Boutaud O, Holinstat M. Protein kinase C regulation of 12-lipoxygenase-mediated human platelet activation. Mol Pharmacol 2011; 81:420-30. [PMID: 22155783 DOI: 10.1124/mol.111.075630] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Platelet activation is important in the regulation of hemostasis and thrombosis. Uncontrolled activation of platelets may lead to arterial thrombosis, which is a major cause of myocardial infarction and stroke. After activation, metabolism of arachidonic acid (AA) by 12-lipoxygenase (12-LOX) may play a significant role in regulating the degree and stability of platelet activation because inhibition of 12-LOX significantly attenuates platelet aggregation in response to various agonists. Protein kinase C (PKC) activation is also known to be an important regulator of platelet activity. Using a newly developed selective inhibitor for 12-LOX and a pan-PKC inhibitor, we investigated the role of PKC in 12-LOX-mediated regulation of agonist signaling in the platelet. To determine the role of PKC within the 12-LOX pathway, a number of biochemical endpoints were measured, including platelet aggregation, calcium mobilization, and integrin activation. Inhibition of 12-LOX or PKC resulted in inhibition of dense granule secretion and attenuation of both aggregation and αIIbβ(3) activation. However, activation of PKC downstream of 12-LOX inhibition rescued agonist-induced aggregation and integrin activation. Furthermore, inhibition of 12-LOX had no effect on PKC-mediated aggregation, indicating that 12-LOX is upstream of PKC. These studies support an essential role for PKC downstream of 12-LOX activation in human platelets and suggest 12-LOX as a possible target for antiplatelet therapy.
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Affiliation(s)
- Jennifer Yeung
- Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Kamruzzaman SM, Endale M, Oh WJ, Park SC, Kim TH, Lee IK, Cho JY, Park HJ, Kim SK, Yun BS, Rhee MH. Antiplatelet activity of Phellinus baummii methanol extract is mediated by cyclic AMP elevation and inhibition of collagen-activated integrin-α(IIb) β₃ and MAP kinase. Phytother Res 2011; 25:1596-603. [PMID: 21394810 DOI: 10.1002/ptr.3450] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 01/09/2011] [Accepted: 01/26/2011] [Indexed: 01/12/2023]
Abstract
Phellinus baumii is a mushroom that has been used as folk medicine against various diseases and is reported to have antidiabetic, anticancer, antioxidant, antiinflammatory and antihypertensive activities. However, information on the effects of P. baumii extract in platelet function is limited. Therefore, the aim of this study was to examine the impact of a P. baumii methanol extract (PBME) on platelet activation and to investigate the mechanism behind its antiplatelet activity. PBME effects on agonist-induced platelet aggregation, granule secretion, [Ca²⁺](i) mobilization, α(IIb) β₃ activation, cyclic AMP release and mitogen-activated protein kinase (MAPK) phosphorylations were studied using rat platelets. PBME dose-dependently inhibited collagen, thrombin and ADP-induced platelet aggregation with an IC₅₀ of 51.0 ± 2.4, 54.0 ± 2.1 and 53.0 ± 4.3 μg/mL, respectively. Likewise, thrombin-induced [Ca²⁺](i) and collagen-activated ATP secretions were suppressed in PBME treated platelets. Aggregation and ATP secretion were also markedly attenuated by PBME alone or in combination with PP2 (Src inhibitor) and U-73122 (PLC inhibitor) in collagen-stimulated platelets. Besides, PBME treatment elevated basal cyclic AMP levels and inhibited collagen-induced integrin-α(IIb) β₃ activation. Moreover, PBME attenuated extracellular-signal-regulated protein kinase 2 (ERK2) and c-Jun N-terminal kinase 1 (JNK1) phosphorylations. Further PD98059 (ERK inhibitor) and SP60025 (JNK inhibitor) reduced collagen-induced platelet aggregation and ATP secretion. In conclusion, the observed PBME antiplatelet activity may be mediated by activation of cyclic AMP and inhibition of ERK2 and JNK1 phosphorylations. Finally, these data suggest that PBME may have therapeutic potential for the treatment of cardiovascular diseases that involve aberrant platelet function.
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Affiliation(s)
- S M Kamruzzaman
- College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Republic of Korea
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Platelet activation in essential hypertension: implications for antiplatelet treatment. Am J Hypertens 2010; 23:229-36. [PMID: 20094035 DOI: 10.1038/ajh.2009.247] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Essential hypertension is associated with increased risk of arterial thrombotic disease. Among other factors, enhanced platelet activity contributes significantly to this phenomenon. An increased level of circulating monocyte-platelet aggregates (MPAs) represents one of the most robust markers of platelet activation; furthermore, these aggregates are also believed to contribute to the pathophysiology of atherothrombotic disease. Putative mechanisms that contribute to platelet activation in essential hypertension include endothelial dysfunction, neurohumoral (sympathetic and renin-angiotensin systems) overactivity, decreased platelet nitric oxide (NO) biosynthesis, and platelet degranulation secondary to increased shear. Current recommendations are that hypertensive patients receive aspirin therapy only if their calculated cardiovascular risk is high and their blood pressure (BP) is adequately controlled. By contrast, the use of antiplatelet treatment in low-risk hypertensive patients is not established and merits further investigation. Moreover, the place of alternative antiplatelet agents other than aspirin, such as clopidogrel, is unclear at present. Some experimental evidence suggests that clopidogrel may confer an additive protective effect over and above aspirin in hypertensive patients, by virtue of effects on the evolution of the atherosclerotic process. This now needs to be investigated in long-term clinical outcome studies.
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Rex S, Beaulieu LM, Perlman DH, Vitseva O, Blair PS, McComb ME, Costello CE, Freedman JE. Immune versus thrombotic stimulation of platelets differentially regulates signalling pathways, intracellular protein-protein interactions, and alpha-granule release. Thromb Haemost 2009; 102:97-110. [PMID: 19572074 DOI: 10.1160/th08-08-0513] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In addition to haemostasis, platelets mediate inflammation and clearance of bacteria from the bloodstream. As with platelet-platelet interactions, platelet-bacteria interactions involve cytoskeletal rearrangements and release of granular content. Stimulation of the immune Toll-like receptor 2 (TLR2) on the platelet surface, activates phosphoinositide-3-kinase (PI3K) and causes platelet activation and platelet-dependent thrombosis. It remains unknown if platelet activation by immune versus thrombotic pathways leads to the differential regulation of signal transduction, protein-protein interactions, and alpha-granule release, and the physiological relevance of these potential differences. We investigated these processes after immune versus thrombotic platelet stimulation. We examined selected signalling pathways and found that phosphorylation kinetics of Akt, ERK1/2 and p38 differed dramatically between agonists. Next, we investigated platelet protein-protein interactions by mass spectrometry (MS)-based proteomics specifically targeting cytosolic factor XIIIa (FXIIIa) because of its function as a cytoskeleton-crosslinking protein whose binding partners have limited characterisation. Four FXIIIa-binding proteins were identified, two of which are novel interactions: FXIIIa-focal adhesion kinase (FAK) and FXIIIa-gelsolin. The binding of FAK to FXIIIa was found to be altered differentially by immune versus thrombotic stimulation. Lastly, we studied the effect of thrombin versus Pam(3)CSK(4) stimulation on alpha-granule release and observed differential release patterns for selected granule proteins and decreased fibrin clot formation compared with thrombin. The inhibition of PI3K caused a decrease in protein release after Pam(3)CSK(4)- but not after thrombin-stimulation. In summary, stimulation of platelets by either thrombotic or immune receptors leads to markedly different signalling responses and granular protein release consistent with differential contribution to coagulation and thrombosis.
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Affiliation(s)
- Sybille Rex
- Whitaker Cardiovascular Institute, Department of Medicine, Boston University School of Medicine, Boston, 02118 MA, USA
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Abstract
The importance of the second messengers calcium (Ca(2+)) and diacylglycerol (DAG) in platelet signal transduction was established more than 30 years ago. Whereas protein kinase C (PKC) family members were discovered as the targets of DAG, little is known about the molecular identity of the main Ca(2+) sensor(s). We here identify Ca(2+) and DAG-regulated guanine nucleotide exchange factor I (CalDAG-GEFI) as a critical molecule in Ca(2+)-dependent platelet activation. CalDAG-GEFI, through activation of the small GTPase Rap1, directly triggers integrin activation and extracellular signal-regulated kinase-dependent thromboxane A(2) (TxA(2)) release. CalDAG-GEFI-dependent TxA(2) generation provides crucial feedback for PKC activation and granule release, particularly at threshold agonist concentrations. PKC/P2Y12 signaling in turn mediates a second wave of Rap1 activation, necessary for sustained platelet activation and thrombus stabilization. Our results lead to a revised model for platelet activation that establishes one molecule, CalDAG-GEFI, at the nexus of Ca(2+)-induced integrin activation, TxA(2) generation, and granule release. The preferential activation of CalDAG-GEFI over PKC downstream of phospholipase C activation, and the different kinetics of CalDAG-GEFI- and PKC/P2Y12-mediated Rap1 activation demonstrate an unexpected complexity to the platelet activation process, and they challenge the current model that DAG/PKC-dependent signaling events are crucial for the initiation of platelet adhesion.
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Abstract
A rise in the intracellular calcium (Ca2+) concentration is a major component of the signaling mechanisms regulating platelet function in thrombosis and hemostasis. Previous studies, however, failed to identify many key molecules regulating Ca2+ signaling in platelets. Here, we review recent findings, which identified CalDAG-GEFI as a critical Ca2+ sensor that links increases in intracellular Ca2+ to integrin activation, TxA2 formation, and granule release in stimulated platelets. Furthermore, we summarize work that lead to the discovery of STIM1 and Orai1 as key regulators of store-operated calcium entry (SOCE) in platelets. A short discussion on the usefulness of each molecule as a potential new target for antiplatelet therapy is included.
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Affiliation(s)
- W Bergmeier
- Cardeza Foundation and Department of Medicine, Thomas Jefferson University, Philadelphia, PA, USA.
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Abstract
Protein kinase C (PKC) isoforms have been implicated in several platelet functional responses, but the contribution of individual isoforms has not been thoroughly evaluated. Novel PKC isoform PKC-theta is activated by glycoprotein VI (GPVI) and protease-activated receptor (PAR) agonists, but not by adenosine diphosphate. In human platelets, PKC-theta-selective antagonistic (RACK; receptor for activated C kinase) peptide significantly inhibited GPVI and PAR-induced aggregation, dense and alpha-granule secretion at low agonist concentrations. Consistently, in murine platelets lacking PKC-theta, platelet aggregation and secretion were also impaired. PKC-mediated phosphorylation of tSNARE protein syntaxin-4 was strongly reduced in human platelets pretreated with PKC-theta RACK peptide, which may contribute to the lower levels of granule secretion when PKC-theta function is lost. Furthermore, the level of JON/A binding to activated alpha(IIb)beta(3) receptor was also significantly decreased in PKC-theta(-/-) mice compared with wild-type littermates. PKC-theta(-/-) murine platelets showed significantly lower agonist-induced thromboxane A(2) (TXA(2)) release through reduced extracellular signal-regulated kinase phosphorylation. Finally, PKC-theta(-/-) mice displayed unstable thrombus formation and prolonged arterial occlusion in the FeCl(3) in vivo thrombosis model compared with wild-type mice. In conclusion, PKC-theta isoform plays a significant role in platelet functional responses downstream of PAR and GPVI receptors.
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Adam F, Kauskot A, Rosa JP, Bryckaert M. Mitogen-activated protein kinases in hemostasis and thrombosis. J Thromb Haemost 2008; 6:2007-16. [PMID: 18826389 DOI: 10.1111/j.1538-7836.2008.03169.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The mitogen-activated protein (MAP) kinases ERK2, p38 and JNK1 are present in platelets and are activated by various stimuli, such as thrombin, collagen, von Willebrand factor (VWF) and ADP. Until recently, MAP kinases were only studied in the conventional model of agonist-induced platelet aggregation mediated by fibrinogen and integrin alphaIIbbeta3. However, this approach is likely to be too limited for a physiological understanding of platelet MAP kinases and their signaling pathways. Recent studies with varying blood-flow conditions and animal models of thrombosis have provided deeper insight into the role of MAP kinases in thrombus formation and the dependence of these kinases on shear conditions. This review summarizes and discusses the physiological functions of these kinases in hemostasis and thrombosis as revealed by various technical approaches.
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Affiliation(s)
- F Adam
- Centre de Recherche Cardiovasculaire INSERM Lariboisiére U689, Hôpital Lariboisiére, Paris, France
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Hunter RW, Harper MT, Hers I. The PKB inhibitor Akti-1/2 potentiates PAR-1-mediated platelet function independently of its ability to block PKB. J Thromb Haemost 2008; 6:1923-32. [PMID: 18761726 DOI: 10.1111/j.1538-7836.2008.03140.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND The role of PKB in platelet function is poorly defined due to the lack of genuinely selective small-molecule inhibitors and limiting genetic models. Recently, a selective, non-ATP-competitive PKB inhibitor, Akti-1/2 has been reported, but the efficacy and specificity against PKB activation in platelet function is unknown. OBJECTIVE AND METHODS To determine the effect of the PKB inhibitor Akti-1/2 on PKB activation and platelet function by Western blotting and aggregometry/flow cytometry, respectively. RESULTS Akti-1/2 potently inhibited thrombin-mediated PKB phosphorylation on Thr(308) and Ser(473) and phosphorylation of its downstream substrate GSK3beta, with a negligible effect on the phosphorylation of pleckstrin, p38, ERK and JNK. Surprisingly, Akti-1/2 strongly potentiated PAR-1-mediated platelet aggregation. This effect persisted in the presence of PI3 kinase inhibitors, indicating a mechanism of action that is independent of PKB. Potentiation of aggregation by Akti-1/2 was associated with increased [Ca(++)](i), PKC activation and degranulation and was ablated by agents that antagonized this pathway. CONCLUSIONS The PKB inhibitor Akti-1/2 increases PAR-1-mediated platelet responses in a PKB-independent, Ca(++)/PKC-dependent manner. This effect is strong and rapid and may impact on the therapeutic application of Akti-1/2 and structurally related compounds.
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Affiliation(s)
- R W Hunter
- Department of Biochemistry, School of Medicine Sciences, University of Bristol, Bristol, UK
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Yacoub D, Théorêt JF, Villeneuve L, Abou-Saleh H, Mourad W, Allen BG, Merhi Y. Essential Role of Protein Kinase Cδ in Platelet Signaling, αIIbβ3 Activation, and Thromboxane A2 Release. J Biol Chem 2006; 281:30024-35. [PMID: 16895913 DOI: 10.1074/jbc.m604504200] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protein kinase C (PKC) family is an essential signaling mediator in platelet activation and aggregation. However, the relative importance of the major platelet PKC isoforms and their downstream effectors in platelet signaling and function remain unclear. Using isolated human platelets, we report that PKCdelta, but not PKCalpha or PKCbeta, is required for collagen-induced phospholipase C-dependent signaling, activation of alpha(IIb)beta(3), and platelet aggregation. Analysis of PKCdelta phosphorylation and translocation to the membrane following activation by both collagen and thrombin indicates that it is positively regulated by alpha(IIb)beta(3) outside-in signaling. Moreover, PKCdelta triggers activation of the mitogen-activated protein kinase-kinase (MEK)/extracellular-signal regulated kinase (ERK) and the p38 MAPK signaling. This leads to the subsequent release of thromboxane A(2), which is essential for collagen-induced but not thrombin-induced platelet activation and aggregation. This study adds new insight to the role of PKCs in platelet function, where PKCdelta signaling, via the MEK/ERK and p38 MAPK pathways, is required for the secretion of thromboxane A(2).
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Affiliation(s)
- Daniel Yacoub
- Research Center, Montreal Heart Institute and University of Montreal, Montreal, Quebec H1T 1C8, Canada
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Integration of P2Y receptor-activated signal transduction pathways in G protein-dependent signalling networks. Purinergic Signal 2006; 2:451-69. [PMID: 18404483 PMCID: PMC2254474 DOI: 10.1007/s11302-006-9008-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Accepted: 03/17/2006] [Indexed: 12/21/2022] Open
Abstract
The role of nucleotides in intracellular energy provision and nucleic acid synthesis has been known for a long time. In the past decade, evidence has been presented that, in addition to these functions, nucleotides are also autocrine and paracrine messenger molecules that initiate and regulate a large number of biological processes. The actions of extracellular nucleotides are mediated by ionotropic P2X and metabotropic P2Y receptors, while hydrolysis by ecto-enzymes modulates the initial signal. An increasing number of studies have been performed to obtain information on the signal transduction pathways activated by nucleotide receptors. The development of specific and stable purinergic receptor agonists and antagonists with therapeutical potential largely contributed to the identification of receptors responsible for nucleotide-activated pathways. This article reviews the signal transduction pathways activated by P2Y receptors, the involved second messenger systems, GTPases and protein kinases, as well as recent findings concerning P2Y receptor signalling in C6 glioma cells. Besides vertical signal transduction, lateral cross-talks with pathways activated by other G protein-coupled receptors and growth factor receptors are discussed.
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Shankar H, Garcia A, Prabhakar J, Kim S, Kunapuli SP. P2Y12 receptor-mediated potentiation of thrombin-induced thromboxane A2 generation in platelets occurs through regulation of Erk1/2 activation. J Thromb Haemost 2006; 4:638-47. [PMID: 16460446 DOI: 10.1111/j.1538-7836.2006.01789.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Thromboxane A2 (TXA2) is a positive feedback lipid mediator that is generated upon stimulation of platelets with various agonists. Aspirin works as an antithrombotic drug by blocking the generation of TXA2. The aim of this study was to evaluate the role of the purinergic P2Y receptors in thrombin-induced TXA2 generation. RESULTS PAR1-activating peptide (SFLLRN), PAR4-activating peptide (AYPGKF), and thrombin, induced the activation of cytosolic phospholipase A2 (cPLA2), release of arachidonic acid (AA) from membrane-bound phospholipids, and subsequent TXA2 generation in human platelets. The actions of these agonists were significantly inhibited in the presence of the P2Y12 receptor antagonist, AR-C69931MX, but not the P2Y1 receptor antagonist, MRS2179. In addition, AYPGKF- and thrombin-induced TXA2 generation was significantly reduced in platelets from mice dosed with clopidogrel, confirming the results obtained with the human platelets. Also, Pearl mouse platelets that lack releasable nucleotides generated significantly less TXA2 when compared with the wild-type littermates in response to PAR stimulation. Inhibition of extracellular signal-regulated protein kinase 1/2 (Erk 1/2) activation using U0126, an inhibitor of MAP kinase kinase (MEK), suppressed PAR-mediated cPLA2 phosphorylation and TXA2 generation. Further, platelets that were pretreated with AR-C69931MX, as well as Pearl mouse platelets, displayed the reduced levels of Erk1/2 phosphorylation upon stimulation with the PAR agonists. CONCLUSIONS Based on these findings, we conclude that thrombin-induced Erk1/2 activation is essential for PAR-mediated TXA2 generation, which is potentiated by the P2Y12 receptor-mediated signaling pathway but not the P2Y1 receptor-mediated signaling pathway. Finally, using selective inhibitors of Src kinases, we show that PAR-mediated Src activation precedes Erk1/2 activation.
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Affiliation(s)
- H Shankar
- Department of Physiology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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Oury C, Daenens K, Hu H, Toth-Zsamboki E, Bryckaert M, Hoylaerts MF. ERK2 activation in arteriolar and venular murine thrombosis: platelet receptor GPIb vs. P2X. J Thromb Haemost 2006; 4:443-52. [PMID: 16420578 DOI: 10.1111/j.1538-7836.2006.01745.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The functional significance of extracellular signal-regulated kinase 2 (ERK2) activation was investigated during shear induced human platelet aggregation (SIPA) in vitro and during shear controlled thrombosis in vivo in intestinal arterioles and venules of wild type (WT) and transgenic (TG) mice with platelet-specific overexpression of human P2X(1) (TG). In SIPA, ERK2 was rapidly phosphorylated during GPIb stimulation, its activation contributing to SIPA for 50%, independently of P2X(1) regulation. Thrombotic occlusion of injured arterioles occurred considerably faster in TG (4.3 +/- 2.3 min) than in WT (38 +/- 8 min) arterioles, but occlusion times in TG (19 +/- 12) and WT (48 +/- 4.5 min) venules differed less. Both the alphabeta-meATP triggered desensitization of platelet P2X(1), as well as P2X(1) antagonism by NF279 or NF449 prolonged mean occlusion to about 75 min in WT and 65 min in TG arterioles, but venular occlusion times were less affected. Preventing ERK2 activation by U0126 prolonged occlusion times in TG (41 +/- 10 min) and WT (51 +/- 17) arterioles more than in TG (46 +/- 5 min) and WT (56 +/- 6 min) venules, uncovering a role for ERK2 in shear controlled thrombosis. Antagonism of GPIb by a recombinant murine von Willebrand factor (VWF)-A1 fragment prolonged occlusion times to comparable values, ranging from 55 to 58 min, both in TG and WT arterioles and venules. Further inhibition strategies, combining VWF-A1, U0126 and NF449 in WT and TG mice and resulting in occlusion in various time windows, identified that inhibition by VWF-A1 largely abrogated the ERK2 contribution to thrombosis. In conclusion, P2X(1) and ERK2 both participate in shear stress controlled thrombosis, but ERK2 activation is initiated predominantly via GPIb-VWF interactions.
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Affiliation(s)
- C Oury
- Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium
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Vijayan KV, Liu Y, Sun W, Ito M, Bray PF. The Pro33 isoform of integrin beta3 enhances outside-in signaling in human platelets by regulating the activation of serine/threonine phosphatases. J Biol Chem 2005; 280:21756-62. [PMID: 15826939 DOI: 10.1074/jbc.m500872200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Integrin beta(3) is polymorphic at residue 33 (Leu(33) or Pro(33)), and the Pro(33)-positive platelets display enhanced aggregation, P-selectin secretion, and shorter bleeding times. Because outside-in signaling is critical for platelet function, we hypothesized that the Pro(33) variant provides a more efficient signaling than the Leu(33) isoform. When compared with Pro(33)-negative platelets, Pro(33)-positive platelets demonstrated significantly greater serine/threonine phosphorylation of extracellular signal-regulated kinase (ERK2) and myosin light chain (MLC) but not cytoplasmic phospholipase A2 upon thrombin-induced aggregation. Tyrosine phosphorylation of integrin beta(3) and the adaptor protein Shc was no different in the fibrinogen-engaged platelets from both genotypes. The addition of Integrilin (alpha(IIb)beta(3)-fibrinogen blocker) or okadaic acid (serine/threonine phosphatase inhibitor) dramatically enhanced ERK2 and MLC phosphorylation in the Pro(33)-negative platelets when compared with Pro(33)-positive platelets, suggesting that integrin engagement during platelet aggregation activates serine/threonine phosphatases. The phosphatase activity of myosin phosphatase (MP) that dephosphorylates MLC is inactivated by phosphorylation of the myosin binding subunit of MP at Thr(696), and aggregating Pro(33)-positive platelets exhibited an increased Thr(696) phosphorylation of MP. These studies highlight a role for the dephosphorylation events via the serine/threonine phosphatases during the integrin outside-in signaling mechanism, and the Leu(33) --> Pro polymorphism regulates this process. Furthermore, these findings support a mechanism whereby the reported enhanced alpha granule secretion in the Pro(33)-positive platelets could be mediated by an increased phosphorylation of MLC, which in turn is caused by an increased phosphorylation and subsequent inactivation of myosin phosphatase.
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Affiliation(s)
- K Vinod Vijayan
- Department of Medicine, Baylor College of Medicine, One Baylor Plaza, BCM 286, N1319, Houston, TX 77030, USA.
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Roger S, Pawlowski M, Habib A, Jandrot-Perrus M, Rosa JP, Bryckaert M. Costimulation of the Gi-coupled ADP receptor and the Gq-coupled TXA2 receptor is required for ERK2 activation in collagen-induced platelet aggregation. FEBS Lett 2004; 556:227-35. [PMID: 14706855 DOI: 10.1016/s0014-5793(03)01430-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The stimulation of platelets by low doses of collagen induces extracellular signal-regulated kinase 2 (ERK2) activation. In this report, we demonstrate that collagen-induced ERK2 activation depends on thromboxane A(2) (TXA(2)) formation and ADP release. The collagen-induced ERK2 activation was inhibited by indomethacin (88%) and by AR-C69931MX (70%), a specific antagonist of P2Y12, a Gi-coupled ADP receptor. AR-C69931MX (10 microM) inhibition was overcome by epinephrine (1 microM), an agonist of the Gi-coupled alpha(2A)-adrenergic receptor, suggesting that the Gi-coupled receptor was necessary for ERK2 activation by collagen. By contrast, MRS 2179 (10 microM), a specific antagonist of P2Y1, a Gq-coupled ADP receptor, did not affect collagen-induced ERK2 activation. Little or no ERK2 activation was observed with ADP alone (10 microM). By contrast, U46619 (10 microM), a stable analog of TXA(2), induced ERK2 activation in an ADP-dependent manner, via the P2Y12 receptor. These results suggest that the Gi-dependent signaling pathway, stimulated by ADP or epinephrine, was not the only pathway required for ERK2 activation by collagen. Costimulation of the specific G(12/13)-coupled TXA(2) receptor with a low dose of U46619 (10 nM) and of Gi- and Gq-coupled ADP receptor (10 microM) induced very low levels of ERK2 activation, similar to those observed with ADP alone, suggesting that G(12/13) is not involved or not sufficient to induce the additional pathway necessary for ERK2 activation. The Gq-coupled TXA(2) receptor was required for ERK2 activation by U46619 (10 microM) and low doses of collagen, clearly showing that a coordinated pathway through both Gq from TXA(2) and Gi from ADP was necessary for ERK2 activation. Finally, we demonstrate that ERK2 activation is involved in collagen-induced aggregation and secretion.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/metabolism
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Adenosine Diphosphate/analogs & derivatives
- Adenosine Diphosphate/pharmacology
- Adenosine Monophosphate/analogs & derivatives
- Adenosine Monophosphate/pharmacology
- Animals
- Cattle
- Collagen/metabolism
- Collagen/pharmacology
- Enzyme Activation/drug effects
- Epinephrine/pharmacology
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Humans
- Integrin alpha2beta1/metabolism
- Membrane Proteins/antagonists & inhibitors
- Membrane Proteins/metabolism
- Mitogen-Activated Protein Kinase 1/metabolism
- Phosphorylation
- Platelet Aggregation/drug effects
- Platelet Membrane Glycoproteins/metabolism
- Protein Kinase C/metabolism
- Purinergic P2 Receptor Antagonists
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2Y12
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
- Signal Transduction
- Thromboxane A2/metabolism
- Thromboxane A2/pharmacology
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Affiliation(s)
- Séverine Roger
- U348 INSERM, IFR 6 Circulation Lariboisière, Hôpital Lariboisière, 41 Bd de la Chapelle, 75475 Cedex 10, Paris, France
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Vega-Ostertag M, Harris EN, Pierangeli SS. Intracellular events in platelet activation induced by antiphospholipid antibodies in the presence of low doses of thrombin. ACTA ACUST UNITED AC 2004; 50:2911-9. [PMID: 15457460 DOI: 10.1002/art.20434] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Thrombosis and thrombocytopenia are features of the antiphospholipid syndrome (APS), suggesting that antiphospholipid antibodies (aPL) may bind platelets, causing activation and aggregation of platelets and thrombosis. The intracellular events involved in aPL-mediated platelet activation are not fully understood and are therefore the subject of this study. METHODS IgG fractions and their F(ab')(2) fragments were purified from the sera of 7 patients with APS and from the pooled sera of 10 healthy subjects (as controls). Phosphorylation of p38 MAPK, ERK-1/2, and [Ca(2+)]-dependent cytosolic phospholipase A(2) (cPLA(2)) was determined in lysates of washed platelets pretreated with low doses of thrombin and aPL or control IgG or their F(ab')(2) fragments, by immunoblot. The effects of aPL on platelet aggregation in the presence or absence of a p38 MAPK inhibitor, SB203580, were examined. Thromboxane B(2) (TXB(2)) production was detected by enzyme-linked immunosorbent assay on gel-filtered platelets treated with aPL and thrombin, with or without SB203580. Calcium mobilization studies were done utilizing a fluorometric assay. RESULTS Treatment of platelets with IgG aPL, or their F(ab')(2) fragments, in conjunction with subactivating doses of thrombin resulted in a significant increase in phosphorylation of p38 MAPK. Neither the IgG aPL nor their F(ab')(2) fragments increased significantly the phosphorylation of ERK-1/2 MAPKs. Furthermore, pretreatment of platelets with SB203580 completely abrogated the aPL-mediated enhanced aggregation of the platelets. Platelets treated with F(ab')(2) aPL and thrombin produced significantly larger amounts of TXB(2) when compared with controls, and this effect was completely abrogated by treatment with SB203580. In addition, cPLA(2) was also significantly phosphorylated in platelets treated with thrombin and F(ab')(2) aPL. There were no significant changes in intracellular [Ca(2+)] when platelets were treated with aPL and low doses of thrombin. CONCLUSION The data strongly indicate that aPL in the presence of subactivating doses of thrombin induce the production of TXB(2) mainly through the activation of p38 MAPK and subsequent phosphorylation of cPLA(2). The ERK-1/2 pathway does not seem to be involved in this process, at least in the early stages of aPL-mediated platelet activation.
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Pierangeli SS, Vega-Ostertag M, Harris EN. Intracellular signaling triggered by antiphospholipid antibodies in platelets and endothelial cells: a pathway to targeted therapies. Thromb Res 2004; 114:467-76. [PMID: 15507280 DOI: 10.1016/j.thromres.2004.06.031] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 06/11/2004] [Accepted: 06/23/2004] [Indexed: 10/26/2022]
Abstract
Understanding the intracellular events triggered by antiphospholipid (aPL) antibodies in platelets and endothelial cells (ECs) is important in designing new modalities of targeted therapies for the treatment of thrombosis in Antiphospholipid Syndrome (APS). A recent study showed a significant increase in the expression of GPIIb/IIIa on platelets treated with aPL antibodies and a thrombin receptor peptide agonist (TRAP), and these effects were abrogated by hydroxychloroquine (HQ). Hydroxychloroquine has also been shown to reduce in vivo aPL-induced thrombus formation. Furthermore, aPL-enhanced thrombosis in vivo can be abrogated by infusions of a GPIIb/IIIa antagonist (1B5) monoclonal antibody, and aPL-mediated thrombophilia is not observed in GPIIb/IIIa-deficient mice. Treatment of platelets with aPL antibodies has resulted in a significant increase in p38 mitogen-activated protein kinase (p38MAPK) phosphorylation and aPL-induced platelet aggregation and thromboxane B2 (TXB2) production was abrogated by SB203580 (a p38MAPK inhibitor). aPL antibodies induce increased expression, function and transcription of tissue factor (TF) on EC. Activation of ECs and thrombogenicity of aPL in vivo can be reversed by treatment of the animals with statins. Upregulation of TF on ECs can also be abrogated by treatment of the cells with fluvastatin. There is also indication of activation of nuclear factor kappa B (NFkappaB), increase in phosphorylation of p38MAPK in ECs by aPL antibodies that can be reversed by specific inhibitors MG132 and SB203580, respectively. The data open the possibility to new treatment modalities that may include the use of hydroxychloroquine, statins, specific antagonists of GPIIb/IIIa (such as abciximab or equivalent) and specific p38MAPK inhibitors, after the completion of well-designed clinical studies.
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Affiliation(s)
- Silvia S Pierangeli
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310-1495, USA.
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Chen Z, Rola-Pleszczynski M, Stankova J. Activation of ERK1/2 by platelet-activating factor receptor is independent of receptor internalisation and G-protein activation. Cell Signal 2003; 15:843-50. [PMID: 12834809 DOI: 10.1016/s0898-6568(03)00056-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Platelet-activating factor (PAF) is a potent pro-inflammatory phospholipid mediator involved in a broad range of physiological and pathophysiological processes. The receptor of PAF (PAFR) is a heptahelical G-protein-coupled receptor. We have shown previously that upon agonist stimulation, PAFR internalised through clathrin-coated vesicles in an arrestin-dependent, but G-protein-coupling-independent manner. In the current report, we demonstrate that PAF stimulates Erk1/2 phosphorylation and: (1). dominant negative mutants of arrestins and dynamin do not influence Erk1/2 activation, (2). hypertonic conditions do not decrease the extent of Erk1/2 phosphorylation, (3). internalisation-deficient and/or G-protein-coupling-deficient mutants of PAFR activate Erk1/2 as efficiently as the wild-type PAFR, and (4). inhibition of epidermal growth factor receptor (EGFR) does not block Erk1/2 activation. Taken together, our results suggest that PAFR-mediated activation of mitogen-activated protein kinases Erk1/2 does not require receptor endocytosis, receptor tyrosine kinase transactivation or G-protein activation. In addition, our studies reveal that PAFR-mediated signals of G-protein activation, receptor internalisation and MAPK activation are differentially regulated by receptor structure and/or conformation.
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Affiliation(s)
- Zhangguo Chen
- Department of Pediatrics, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1H 5N4
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45
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Kang KW, Choi SY, Cho MK, Lee CH, Kim SG. Thrombin induces nitric-oxide synthase via Galpha12/13-coupled protein kinase C-dependent I-kappaBalpha phosphorylation and JNK-mediated I-kappaBalpha degradation. J Biol Chem 2003; 278:17368-78. [PMID: 12606553 DOI: 10.1074/jbc.m300471200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An imbalance between thrombin and antithrombin III contributed to vascular hyporeactivity in sepsis, which can be attributed to excess NO production by inducible nitric-oxide synthase (iNOS). In view of the importance of the thrombin-activated coagulation pathway and excess NO as the culminating factors in vascular hyporeactivity, this study investigated the effects of thrombin on the induction of iNOS and NO production in macrophages. Thrombin induced iNOS protein in the Raw264.7 cells, which was inhibited by a thrombin inhibitor, LB30057. Thrombin increased NF-kappaB DNA binding, whose band was supershifted with anti-p65 and anti-p50 antibodies. Thrombin elicited the phosphorylation and degradation of I-kappaBalpha prior to the nuclear translocation of p65. The NF-kappaB-mediated iNOS induction was stimulated by the overexpression of activated mutants of Galpha(12/13) (Galpha(12/13)QL). Protein kinase C depletion inhibited I-kappaBalpha degradation, NF-kappaB activation, and iNOS induction by thrombin or the iNOS induction by Galpha(12/13)QL. JNK, p38 kinase, and ERK were all activated by thrombin. JNK inhibition by the stable transfection with a dominant negative mutant of JNK1 (JNK1(-)) completely suppressed the NF-kappaB-mediated iNOS induction by thrombin. Conversely, the inhibition of p38 kinase enhanced the expression of iNOS. In addition, JNK and p38 kinase oppositely controlled the NF-kappaB-mediated iNOS induction by Galpha(12/13)QL. Hence, iNOS induction by thrombin was regulated by the opposed functions of JNK and p38 kinase downstream of Galpha(12/13). In the JNK1(-) cells, thrombin did not increase either the NF-kappaB binding activity or I-kappaBalpha degradation despite I-kappaBalpha phosphorylation. These results demonstrated that thrombin induces iNOS in macrophages via Galpha(12) and Galpha(13), which leads to NF-kappaB activation involving the protein kinase C-dependent phosphorylation of I-kappaBalpha and the JNK-dependent degradation of phosphorylated I-kappaBalpha.
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Affiliation(s)
- Keon Wook Kang
- National Research Laboratory, College of Pharmacy, Seoul National University, Sillim-dong, Seoul 151-742, Korea
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Kamiguti AS, Harris RJ, Slupsky JR, Baker PK, Cawley JC, Zuzel M. Regulation of hairy-cell survival through constitutive activation of mitogen-activated protein kinase pathways. Oncogene 2003; 22:2272-84. [PMID: 12700663 DOI: 10.1038/sj.onc.1206398] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The hairy cells (HCs) of hairy-cell leukemia are intrinsically activated mature clonal B cells. The aims of this study were to gain further insights into the nature of this activation and to assess its importance for the prolonged HC survival in this chronic disease. We show that HCs contain phosphorylated/activated p38 MAPK, JNK and ERK1/ERK2 (ERK1/2). PKC inhibitors increased the activation of p38 and JNK, but reduced the phosphorylation of ERK1/2. Moreover, PKC inhibition resulted in cell death; cell death was also observed when the activation of ERK1/2 in HCs was abrogated with an inhibitor of MEK1/2 activation. In addition to PKC, active Src kinase was also shown to be involved in the maintenance of Raf-independent ERK activation in HCs. During cell culture on a nonadherent surface, ERK phosphorylation was sustained, while phosphorylation of p38 and JNK decreased. This decrease was not observed in HCs cultured on vitronectin (VN), indicating that p38/JNK activation is probably a consequence of in vivo HC interaction with VN present in abundance in the red pulp of the spleen. Taken together, these results suggest that active p38/JNK make HCs susceptible to apoptosis, but the cells are effectively rescued by ERK activation involving constitutively active PKC and Src. These findings are relevant for the understanding of the prolonged cell survival of HCs and their selective sensitivity to some chemotherapeutic agents.
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Affiliation(s)
- Aura S Kamiguti
- Department of Haematology, Royal Liverpool University Hospital, University of Liverpool, UK.
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Cichowski K, Santiago S, Jardim M, Johnson BW, Jacks T. Dynamic regulation of the Ras pathway via proteolysis of the NF1 tumor suppressor. Genes Dev 2003; 17:449-54. [PMID: 12600938 PMCID: PMC195996 DOI: 10.1101/gad.1054703] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mutations in the NF1 tumor suppressor underlie the familial tumor predisposition syndrome neurofibromatosis type I. Although its encoded protein, neurofibromin, functions as a Ras-GTPase activating protein (GAP), nothing is known about how it is normally regulated or its precise role in controlling Ras signaling pathways. We show here that neurofibromin is dynamically regulated by the ubiquitin-proteasome pathway. Degradation is rapidly triggered in response to a variety of growth factors and requires sequences adjacent to the catalytic GAP-related domain of neurofibromin. However, whereas degradation is rapid, neurofibromin levels are re-elevated shortly after growth factor treatment. Accordingly, Nf1-deficient mouse embryonic fibroblasts (MEFs) exhibit an enhanced activation of Ras, prolonged Ras and ERK activities, and proliferate in response to subthreshold levels of growth factors. Thus, the dynamic proteasomal regulation of neurofibromin represents an important mechanism of controlling both the amplitude and duration of Ras-mediated signaling. Furthermore, this previously unrecognized Ras regulatory mechanism may be exploited therapeutically.
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Affiliation(s)
- Karen Cichowski
- Genetics Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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