1
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Jooss NJ, Diender MG, Fernández DI, Huang J, Heubel-Moenen FCJ, van der Veer A, Kuijpers MJE, Poulter NS, Henskens YMC, Te Loo M, Heemskerk JWM. Restraining of glycoprotein VI- and integrin α2β1-dependent thrombus formation by platelet PECAM1. Cell Mol Life Sci 2024; 81:44. [PMID: 38236412 PMCID: PMC10796532 DOI: 10.1007/s00018-023-05058-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/15/2023] [Accepted: 11/21/2023] [Indexed: 01/19/2024]
Abstract
The platelet receptors, glycoprotein VI (GPVI) and integrin α2β1 jointly control collagen-dependent thrombus formation via protein tyrosine kinases. It is unresolved to which extent the ITIM (immunoreceptor tyrosine-based inhibitory motif) receptor PECAM1 and its downstream acting protein tyrosine phosphatase PTPN11 interfere in this process. Here, we hypothesized that integrin α2β1 has a co-regulatory role in the PECAM1- and PTPN11-dependent restraint of thrombus formation. We investigated platelet activation under flow on collagens with a different GPVI dependency and using integrin α2β1 blockage. Blood was obtained from healthy subjects and from patients with Noonan syndrome with a gain-of-function mutation of PTPN11 and variable bleeding phenotype. On collagens with decreasing GPVI activity (types I, III, IV), the surface-dependent inhibition of PECAM1 did not alter thrombus parameters using control blood. Blockage of α2β1 generally reduced thrombus parameters, most effectively on collagen IV. Strikingly, simultaneous inhibition of PECAM1 and α2β1 led to a restoration of thrombus formation, indicating that the suppressing signaling effect of PECAM1 is masked by the platelet-adhesive receptor α2β1. Blood from 4 out of 6 Noonan patients showed subnormal thrombus formation on collagen IV. In these patients, effects of α2β1 blockage were counterbalanced by PECAM1 inhibition to a normal phenotype. In summary, we conclude that the suppression of GPVI-dependent thrombus formation by either PECAM1 or a gain-of-function of PTPN11 can be overruled by α2β1 engagement.
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Affiliation(s)
- Natalie J Jooss
- Department of Biochemistry, Maastricht University, Maastricht, The Netherlands
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
- Molecular Haematology Unit, University of Oxford, Headington, OX3 9DS, UK
| | - Marije G Diender
- Department of Pediatric Hematology, Amalia Children's Hospital, Radboud UMC, Nijmegen, The Netherlands
| | - Delia I Fernández
- Department of Biochemistry, Maastricht University, Maastricht, The Netherlands
- Platelet Proteomics Group, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Jingnan Huang
- Department of Biochemistry, Maastricht University, Maastricht, The Netherlands
- Platelet Proteomics Group, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Floor C J Heubel-Moenen
- Department of Internal Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Arian van der Veer
- Department of Pediatric Hematology, Amalia Children's Hospital, Radboud UMC, Nijmegen, The Netherlands
- Department of Pediatric Hematology, Maastricht University Medical Center, Maastricht, The Netherlands
| | | | - Natalie S Poulter
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, Nottingham, Midlands, UK
| | - Yvonne M C Henskens
- Central Diagnostic Laboratory, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Maroeska Te Loo
- Department of Pediatric Hematology, Amalia Children's Hospital, Radboud UMC, Nijmegen, The Netherlands
| | - Johan W M Heemskerk
- Department of Biochemistry, Maastricht University, Maastricht, The Netherlands.
- Synapse Research Institute Maastricht, Kon. Emmaplein 7, 6217 KD, Maastricht, The Netherlands.
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2
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Konstorum A, Mohanty S, Zhao Y, Melillo A, Vander Wyk B, Nelson A, Tsang S, Blevins TP, Belshe R, Chawla DG, Rondina MT, Gill TM, Montgomery RR, Allore HG, Kleinstein SH, Shaw AC. Platelet response to influenza vaccination reflects effects of aging. Aging Cell 2023; 22:e13749. [PMID: 36656789 PMCID: PMC9924941 DOI: 10.1111/acel.13749] [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: 05/16/2022] [Revised: 10/21/2022] [Accepted: 11/15/2022] [Indexed: 01/20/2023] Open
Abstract
Platelets are uniquely positioned as mediators of not only hemostasis but also innate immunity. However, how age and geriatric conditions such as frailty influence platelet function during an immune response remains unclear. We assessed the platelet transcriptome at baseline and following influenza vaccination in Younger (age 21-35) and Older (age ≥65) adults (including community-dwelling individuals who were largely non-frail and skilled nursing facility (SNF)-resident adults who nearly all met criteria for frailty). Prior to vaccination, we observed an age-associated increase in the expression of platelet activation and mitochondrial RNAs and decrease in RNAs encoding proteins mediating translation. Age-associated differences were also identified in post-vaccination response trajectories over 28 days. Using tensor decomposition analysis, we found increasing RNA expression of genes in platelet activation pathways in young participants, but decreasing levels in (SNF)-resident adults. Translation RNA trajectories were inversely correlated with these activation pathways. Enhanced platelet activation was found in community-dwelling older adults at the protein level, compared to young individuals both prior to and post-vaccination; whereas SNF residents showed decreased platelet activation compared to community-dwelling older adults that could reflect the influence of decreased translation RNA expression. Our results reveal alterations in the platelet transcriptome and activation responses that may contribute to age-associated chronic inflammation and the increased incidence of thrombotic and pro-inflammatory diseases in older adults.
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Affiliation(s)
- Anna Konstorum
- Department of PathologyYale School of MedicineNew HavenConnecticutUSA
| | - Subhasis Mohanty
- Department of Internal Medicine, Section of Infectious DiseasesYale School of MedicineNew HavenConnecticutUSA
| | - Yujiao Zhao
- Section of Rheumatology, Department of Internal MedicineYale School of MedicineNew HavenConnecticutUSA
| | - Anthony Melillo
- Department of PathologyYale School of MedicineNew HavenConnecticutUSA
| | - Brent Vander Wyk
- Department of Internal Medicine, Section of Geriatrics and Program on AgingYale School of MedicineNew HavenConnecticutUSA
| | - Allison Nelson
- Department of Internal Medicine, Section of Infectious DiseasesYale School of MedicineNew HavenConnecticutUSA
| | - Sui Tsang
- Department of Internal Medicine, Section of Geriatrics and Program on AgingYale School of MedicineNew HavenConnecticutUSA
| | - Tamara P. Blevins
- Division of Infectious Diseases, Department of MedicineSaint Louis University School of MedicineSt. LouisMissouriUSA
| | - Robert B. Belshe
- Division of Infectious Diseases, Department of MedicineSaint Louis University School of MedicineSt. LouisMissouriUSA
| | - Daniel G. Chawla
- Program in Computational Biology and BioinformaticsYale UniversityNew HavenConnecticutUSA
| | - Matthew T. Rondina
- Departments of Internal Medicine and Pathology, and the Molecular Medicine ProgramUniversity of Utah HealthSalt Lake CityUtahUSA
- Department of Medicine and the GRECCGeorge E. Wahlen VAMCSalt Lake CityUtahUSA
| | - Thomas M. Gill
- Department of Internal Medicine, Section of Geriatrics and Program on AgingYale School of MedicineNew HavenConnecticutUSA
| | - Ruth R. Montgomery
- Section of Rheumatology, Department of Internal MedicineYale School of MedicineNew HavenConnecticutUSA
| | - Heather G. Allore
- Department of Internal Medicine, Section of Geriatrics and Program on AgingYale School of MedicineNew HavenConnecticutUSA
| | - Steven H. Kleinstein
- Department of PathologyYale School of MedicineNew HavenConnecticutUSA
- Program in Computational Biology and BioinformaticsYale UniversityNew HavenConnecticutUSA
| | - Albert C. Shaw
- Department of Internal Medicine, Section of Infectious DiseasesYale School of MedicineNew HavenConnecticutUSA
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3
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The Molecular Interaction of Collagen with Cell Receptors for Biological Function. Polymers (Basel) 2022; 14:polym14050876. [PMID: 35267698 PMCID: PMC8912536 DOI: 10.3390/polym14050876] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 01/25/2023] Open
Abstract
Collagen, an extracellular protein, covers the entire human body and has several important biological functions in normal physiology. Recently, collagen from non-human sources has attracted attention for therapeutic management and biomedical applications. In this regard, both land-based animals such as cow, pig, chicken, camel, and sheep, and marine-based resources such as fish, octopus, starfish, sea-cucumber, and jellyfish are widely used for collagen extraction. The extracted collagen is transformed into collagen peptides, hydrolysates, films, hydrogels, scaffolds, sponges and 3D matrix for food and biomedical applications. In addition, many strategic ideas are continuously emerging to develop innovative advanced collagen biomaterials. For this purpose, it is important to understand the fundamental perception of how collagen communicates with receptors of biological cells to trigger cell signaling pathways. Therefore, this review discloses the molecular interaction of collagen with cell receptor molecules to carry out cellular signaling in biological pathways. By understanding the actual mechanism, this review opens up several new concepts to carry out next level research in collagen biomaterials.
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4
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Batis H, Almugairi A, Almugren O, Aljabry M, Alqahtani F, Elbashir E, Elfaki M, Alsultan A. Detrimental variants in MPIG6B in two children with myelofibrosis: Does immune dysregulation contribute to myelofibrosis? Pediatr Blood Cancer 2021; 68:e29062. [PMID: 33871931 DOI: 10.1002/pbc.29062] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/29/2021] [Accepted: 03/30/2021] [Indexed: 12/26/2022]
Affiliation(s)
- Hasan Batis
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Oncology Center, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Areej Almugairi
- Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City and National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Omar Almugren
- Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mansour Aljabry
- Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Fatima Alqahtani
- Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Enas Elbashir
- Department of Pediatric Hematology/Oncology, King Abdullah Specialist Children's Hospital, Riyadh, Saudi Arabia
| | - Mohammed Elfaki
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Oncology Center, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Abdulrahman Alsultan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Oncology Center, King Saud University Medical City, Riyadh, Saudi Arabia
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5
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Soriano Jerez EM, Gibbins JM, Hughes CE. Targeting platelet inhibition receptors for novel therapies: PECAM-1 and G6b-B. Platelets 2021; 32:761-769. [PMID: 33646086 DOI: 10.1080/09537104.2021.1882668] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
While current oral antiplatelet therapies benefit many patients, they deregulate the hemostatic balance leaving patients at risk of systemic side-effects such as hemorrhage. Dual antiplatelet treatment is the standard approach, combining aspirin with P2Y12 blockers. These therapies mainly target autocrine activation mechanisms (TxA2, ADP) and, more recently, the use of thrombin or thrombin receptor antagonists have been added to the available approaches. Recent efforts to develop new classes of anti-platelet drugs have begun to focus on primary platelet activation pathways such as through the immunoreceptor tyrosine-based activation motif (ITAM)-containing collagen receptor GPVI/FcRγ-chain complex. There are already encouraging results from targeting GPVI, with reduced aggregation and smaller arterial thrombi, without major bleeding complications, likely due to overlapping activation signaling pathways with other receptors such as the GPIb-V-IX complex. An alternative approach to reduce platelet activation could be to inhibit this signaling pathway by targeting the inhibitory pathways intrinsic to platelets. Stimulation of endogenous negative modulators could provide more specific inhibition of platelet function, but is this feasible? In this review, we explore the potential of the two major platelet immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing inhibitory receptors, G6b-B and PECAM-1, as antithrombotic targets.
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Affiliation(s)
- Eva M Soriano Jerez
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, UK.,Institute of Experimental Biomedicine, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Jonathan M Gibbins
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, UK
| | - Craig E Hughes
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, UK
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6
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Li Yim AY, Duijvis NW, Ghiboub M, Sharp C, Ferrero E, Mannens MM, D’Haens GR, de Jonge WJ, te Velde AA, Henneman P. Whole-Genome DNA Methylation Profiling of CD14+ Monocytes Reveals Disease Status and Activity Differences in Crohn's Disease Patients. J Clin Med 2020; 9:E1055. [PMID: 32276386 PMCID: PMC7230341 DOI: 10.3390/jcm9041055] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/04/2020] [Accepted: 04/06/2020] [Indexed: 12/13/2022] Open
Abstract
Crohn's disease (CD) is a multifactorial incurable chronic disorder. Current medical treatment seeks to induce and maintain a state of remission. During episodes of inflammation, monocytes infiltrate the inflamed mucosa whereupon they differentiate into macrophages with a pro-inflammatory phenotype. Here, we sought to characterize the circulating monocytes by profiling their DNA methylome and relate it to the level of CD activity. We gathered an all-female age-matched cohort of 16 CD patients and 7 non-CD volunteers. CD patients were further subdivided into 8 CD patients with active disease (CD-active) and 8 CD patients in remission (CD-remissive) as determined by the physician global assessment. We identified 15 and 12 differentially methylated genes (DMGs) when comparing CD with non-CD and CD-active with CD-remissive, respectively. Differential methylation was predominantly found in the promoter regions of inflammatory genes. Comparing our observations with gene expression data on classical (CD14++CD16-), non-classical (CD14+CD16++) and intermediate (CD14++CD16+) monocytes indicated that while 7 DMGs were differentially expressed across the 3 subsets, the remaining DMGs could not immediately be associated with differences in known populations. We conclude that CD activity is associated with differences in DNA methylation at the promoter region of inflammation-associated genes.
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Affiliation(s)
- Andrew Y.F. Li Yim
- Department of Clinical Genetics, Amsterdam University Medical Centers, University of Amsterdam, Genome Diagnostics Laboratory, Amsterdam Reproduction & Development, 1105 AZ Amsterdam, The Netherlands
- R&D GlaxoSmithKline, Stevenage SG1 2NY, UK; (M.G.); (C.S.); (E.F.)
| | - Nicolette W. Duijvis
- Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, 1105 BK Amsterdam, The Netherlands; (N.W.D.); (W.J.d.J.)
- Department of Gastroenterology and Hepatology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, 1105 AZ Amsterdam, The Netherlands;
| | - Mohammed Ghiboub
- R&D GlaxoSmithKline, Stevenage SG1 2NY, UK; (M.G.); (C.S.); (E.F.)
- Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, 1105 BK Amsterdam, The Netherlands; (N.W.D.); (W.J.d.J.)
| | - Catriona Sharp
- R&D GlaxoSmithKline, Stevenage SG1 2NY, UK; (M.G.); (C.S.); (E.F.)
| | - Enrico Ferrero
- R&D GlaxoSmithKline, Stevenage SG1 2NY, UK; (M.G.); (C.S.); (E.F.)
| | - Marcel M.A.M. Mannens
- Department of Clinical Genetics, Amsterdam University Medical Centers, University of Amsterdam, Genome Diagnostics Laboratory, Amsterdam Reproduction & Development, 1105 AZ Amsterdam, The Netherlands
| | - Geert R. D’Haens
- Department of Gastroenterology and Hepatology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, 1105 AZ Amsterdam, The Netherlands;
| | - Wouter J. de Jonge
- Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, 1105 BK Amsterdam, The Netherlands; (N.W.D.); (W.J.d.J.)
- Department of Surgery, University Clinic of Bonn, 53127 Bonn, Germany
| | - Anje A. te Velde
- Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, 1105 BK Amsterdam, The Netherlands; (N.W.D.); (W.J.d.J.)
| | - Peter Henneman
- Department of Clinical Genetics, Amsterdam University Medical Centers, University of Amsterdam, Genome Diagnostics Laboratory, Amsterdam Reproduction & Development, 1105 AZ Amsterdam, The Netherlands
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7
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Zheng J, Zhu MY, Wu F, Kang B, Liang J, Heskia F, Shan YF, Zhang XX. A blood-based 22-gene expression signature for hepatocellular carcinoma identification. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:195. [PMID: 32309342 PMCID: PMC7154425 DOI: 10.21037/atm.2020.01.93] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Background Hepatocellular carcinoma (HCC) is one of the most common and lethal malignancies. Early detection of HCC could largely reduce mortalities. Ultrasonography (US) and serum Alpha Fetoprotein (AFP) test are the screening methods that are most frequently applied to high-risk populations. Due to the poor performance of AFP testing, and the highly operator-dependent nature of US, a biomarker for HCC early diagnosis is highly sought after. We developed a method for HCC screening using a 22-gene expression signature. Methods Peripheral whole blood of 98 patients were processed through microarrays for the first round of feature selection via two strategies, Minimal Redundancy Maximal Relevance and Least Absolute Shrinkage and Selection Operator combined with Support Vector Machine (SVM). Candidate genes were combined for further validation through qPCR in an enlarged population with 316 samples with 104 chronic hepatitis, 112 liver cirrhosis (LC), and 100 HCC. Results A 22-gene signature was established in classifying HCC and non-cancer samples with good performance. The area under curve reached 0.94 in all of the samples and 0.93 in the AFP -negative samples. Conclusions We have established a blood mRNA signature with high performance for HCC screening. Our results show transcriptome of peripheral blood could be valuable source for biomarkers.
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Affiliation(s)
- Jie Zheng
- Department of Interventional Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Ming-Yu Zhu
- Department of Gastroenterology, Ruijin Hospital North, School of Medicine, Shanghai Jiao Tong University, Shanghai 201800, China
| | - Fei Wu
- Fudan University Shanghai Cancer Center - Institut Mérieux Laboratory, Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai 200032, China
| | - Bin Kang
- Fudan University Shanghai Cancer Center - Institut Mérieux Laboratory, Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai 200032, China
| | - Ji Liang
- Fudan University Shanghai Cancer Center - Institut Mérieux Laboratory, Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai 200032, China
| | - Fabienne Heskia
- Medical Diagnostics Discovery Department, bioMérieux, Marcy l'Etoile, France
| | - Yun-Feng Shan
- Department of Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Xin-Xin Zhang
- Research Laboratory of Clinical Virology, Ruijin Hospital and Ruijin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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8
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Hansen M, Zeddies S, Meinders M, di Summa F, Rollmann E, van Alphen FP, Hoogendijk AJ, Moore KS, Halbach M, Gutiérrez L, van den Biggelaar M, Thijssen-Timmer DC, Auburger GW, van den Akker E, von Lindern M. The RNA-Binding Protein ATXN2 is Expressed during Megakaryopoiesis and May Control Timing of Gene Expression. Int J Mol Sci 2020; 21:ijms21030967. [PMID: 32024018 PMCID: PMC7037754 DOI: 10.3390/ijms21030967] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/21/2020] [Accepted: 01/30/2020] [Indexed: 12/13/2022] Open
Abstract
Megakaryopoiesis is the process during which megakaryoblasts differentiate to polyploid megakaryocytes that can subsequently shed thousands of platelets in the circulation. Megakaryocytes accumulate mRNA during their maturation, which is required for the correct spatio-temporal production of cytoskeletal proteins, membranes and platelet-specific granules, and for the subsequent shedding of thousands of platelets per cell. Gene expression profiling identified the RNA binding protein ATAXIN2 (ATXN2) as a putative novel regulator of megakaryopoiesis. ATXN2 expression is high in CD34+/CD41+ megakaryoblasts and sharply decreases upon maturation to megakaryocytes. ATXN2 associates with DDX6 suggesting that it may mediate repression of mRNA translation during early megakaryopoiesis. Comparative transcriptome and proteome analysis on megakaryoid cells (MEG-01) with differential ATXN2 expression identified ATXN2 dependent gene expression of mRNA and protein involved in processes linked to hemostasis. Mice deficient for Atxn2 did not display differences in bleeding times, but the expression of key surface receptors on platelets, such as ITGB3 (carries the CD61 antigen) and CD31 (PECAM1), was deregulated and platelet aggregation upon specific triggers was reduced.
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Affiliation(s)
- Marten Hansen
- Department Hematopoiesis, Sanquin Research, and Landsteiner Laboratory, Amsterdam University Medical Centre, 1066CX Amsterdam, The Netherlands; (M.H.); (S.Z.); (F.d.S.); (K.S.M.); (D.C.T.-T.); (E.v.d.A.)
| | - Sabrina Zeddies
- Department Hematopoiesis, Sanquin Research, and Landsteiner Laboratory, Amsterdam University Medical Centre, 1066CX Amsterdam, The Netherlands; (M.H.); (S.Z.); (F.d.S.); (K.S.M.); (D.C.T.-T.); (E.v.d.A.)
| | - Marjolein Meinders
- Department Blood Cell Research, Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam,1066CX Amsterdam, The Netherlands; (M.M.); (L.G.)
| | - Franca di Summa
- Department Hematopoiesis, Sanquin Research, and Landsteiner Laboratory, Amsterdam University Medical Centre, 1066CX Amsterdam, The Netherlands; (M.H.); (S.Z.); (F.d.S.); (K.S.M.); (D.C.T.-T.); (E.v.d.A.)
| | - Ewa Rollmann
- Experimental Neurology, Goethe University Medical School, 60528 Frankfurt am Main, Germany; (E.R.); (M.H.)
| | - Floris P.J. van Alphen
- Department of Molecular and Cellular Hemostasis, Sanquin Research, 1066CX Amsterdam, The Netherlands (A.J.H.); (M.v.d.B.)
| | - Arjan J. Hoogendijk
- Department of Molecular and Cellular Hemostasis, Sanquin Research, 1066CX Amsterdam, The Netherlands (A.J.H.); (M.v.d.B.)
| | - Kat S. Moore
- Department Hematopoiesis, Sanquin Research, and Landsteiner Laboratory, Amsterdam University Medical Centre, 1066CX Amsterdam, The Netherlands; (M.H.); (S.Z.); (F.d.S.); (K.S.M.); (D.C.T.-T.); (E.v.d.A.)
| | - Melanie Halbach
- Experimental Neurology, Goethe University Medical School, 60528 Frankfurt am Main, Germany; (E.R.); (M.H.)
| | - Laura Gutiérrez
- Department Blood Cell Research, Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam,1066CX Amsterdam, The Netherlands; (M.M.); (L.G.)
| | - Maartje van den Biggelaar
- Department of Molecular and Cellular Hemostasis, Sanquin Research, 1066CX Amsterdam, The Netherlands (A.J.H.); (M.v.d.B.)
| | - Daphne C. Thijssen-Timmer
- Department Hematopoiesis, Sanquin Research, and Landsteiner Laboratory, Amsterdam University Medical Centre, 1066CX Amsterdam, The Netherlands; (M.H.); (S.Z.); (F.d.S.); (K.S.M.); (D.C.T.-T.); (E.v.d.A.)
| | - Georg W.J. Auburger
- Experimental Neurology, Goethe University Medical School, 60528 Frankfurt am Main, Germany; (E.R.); (M.H.)
| | - Emile van den Akker
- Department Hematopoiesis, Sanquin Research, and Landsteiner Laboratory, Amsterdam University Medical Centre, 1066CX Amsterdam, The Netherlands; (M.H.); (S.Z.); (F.d.S.); (K.S.M.); (D.C.T.-T.); (E.v.d.A.)
| | - Marieke von Lindern
- Department Hematopoiesis, Sanquin Research, and Landsteiner Laboratory, Amsterdam University Medical Centre, 1066CX Amsterdam, The Netherlands; (M.H.); (S.Z.); (F.d.S.); (K.S.M.); (D.C.T.-T.); (E.v.d.A.)
- Correspondence: ; Tel.: +31-6-1203-7801
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9
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Vögtle T, Sharma S, Mori J, Nagy Z, Semeniak D, Scandola C, Geer MJ, Smith CW, Lane J, Pollack S, Lassila R, Jouppila A, Barr AJ, Ogg DJ, Howard TD, McMiken HJ, Warwicker J, Geh C, Rowlinson R, Abbott WM, Eckly A, Schulze H, Wright GJ, Mazharian A, Fütterer K, Rajesh S, Douglas MR, Senis YA. Heparan sulfates are critical regulators of the inhibitory megakaryocyte-platelet receptor G6b-B. eLife 2019; 8:e46840. [PMID: 31436532 PMCID: PMC6742478 DOI: 10.7554/elife.46840] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/21/2019] [Indexed: 02/06/2023] Open
Abstract
The immunoreceptor tyrosine-based inhibition motif (ITIM)-containing receptor G6b-B is critical for platelet production and activation. Loss of G6b-B results in severe macrothrombocytopenia, myelofibrosis and aberrant platelet function in mice and humans. Using a combination of immunohistochemistry, affinity chromatography and proteomics, we identified the extracellular matrix heparan sulfate (HS) proteoglycan perlecan as a G6b-B binding partner. Subsequent in vitro biochemical studies and a cell-based genetic screen demonstrated that the interaction is specifically mediated by the HS chains of perlecan. Biophysical analysis revealed that heparin forms a high-affinity complex with G6b-B and mediates dimerization. Using platelets from humans and genetically modified mice, we demonstrate that binding of G6b-B to HS and multivalent heparin inhibits platelet and megakaryocyte function by inducing downstream signaling via the tyrosine phosphatases Shp1 and Shp2. Our findings provide novel insights into how G6b-B is regulated and contribute to our understanding of the interaction of megakaryocytes and platelets with glycans.
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Affiliation(s)
- Timo Vögtle
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Sumana Sharma
- Cell Surface Signalling LaboratoryWellcome Trust Sanger InstituteCambridgeUnited Kingdom
| | - Jun Mori
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Zoltan Nagy
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Daniela Semeniak
- Institute of Experimental BiomedicineUniversity Hospital WürzburgWürzburgGermany
| | - Cyril Scandola
- Université de Strasbourg, Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de StrasbourgStrasbourgFrance
| | - Mitchell J Geer
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Christopher W Smith
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Jordan Lane
- Sygnature Discovery LimitedNottinghamUnited Kingdom
| | | | - Riitta Lassila
- Coagulation Disorders Unit, Department of Hematology, Comprehensive Cancer CenterUniversity of Helsinki, Helsinki University HospitalHelsinkiFinland
- Aplagon OyHelsinkiFinland
| | - Annukka Jouppila
- Coagulation Disorders UnitHelsinki University Hospital Research InstituteHelsinkiFinland
| | - Alastair J Barr
- Department of Biomedical Science, Faculty of Science & TechnologyUniversity of WestminsterLondonUnited Kingdom
| | - Derek J Ogg
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | - Tina D Howard
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | | | - Juli Warwicker
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | - Catherine Geh
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | | | - W Mark Abbott
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | - Anita Eckly
- Université de Strasbourg, Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de StrasbourgStrasbourgFrance
| | - Harald Schulze
- Institute of Experimental BiomedicineUniversity Hospital WürzburgWürzburgGermany
| | - Gavin J Wright
- Cell Surface Signalling LaboratoryWellcome Trust Sanger InstituteCambridgeUnited Kingdom
| | - Alexandra Mazharian
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Klaus Fütterer
- School of Biosciences, College of Life and Environmental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Sundaresan Rajesh
- Institute of Cancer and Genomic Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Michael R Douglas
- Institute of Inflammation and Ageing, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
- Department of NeurologyDudley Group NHS Foundation TrustDudleyUnited Kingdom
- School of Life and Health SciencesAston UniversityBirminghamUnited Kingdom
| | - Yotis A Senis
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
- Université de Strasbourg, Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de StrasbourgStrasbourgFrance
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10
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Kuriri FA, O'Malley CJ, Jackson DE. Molecular mechanisms of immunoreceptors in platelets. Thromb Res 2019; 176:108-114. [DOI: 10.1016/j.thromres.2019.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/20/2019] [Accepted: 01/28/2019] [Indexed: 01/05/2023]
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11
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Huang J, Li X, Shi X, Zhu M, Wang J, Huang S, Huang X, Wang H, Li L, Deng H, Zhou Y, Mao J, Long Z, Ma Z, Ye W, Pan J, Xi X, Jin J. Platelet integrin αIIbβ3: signal transduction, regulation, and its therapeutic targeting. J Hematol Oncol 2019; 12:26. [PMID: 30845955 PMCID: PMC6407232 DOI: 10.1186/s13045-019-0709-6] [Citation(s) in RCA: 198] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 02/21/2019] [Indexed: 12/18/2022] Open
Abstract
Integrins are a family of transmembrane glycoprotein signaling receptors that can transmit bioinformation bidirectionally across the plasma membrane. Integrin αIIbβ3 is expressed at a high level in platelets and their progenitors, where it plays a central role in platelet functions, hemostasis, and arterial thrombosis. Integrin αIIbβ3 also participates in cancer progression, such as tumor cell proliferation and metastasis. In resting platelets, integrin αIIbβ3 adopts an inactive conformation. Upon agonist stimulation, the transduction of inside-out signals leads integrin αIIbβ3 to switch from a low- to high-affinity state for fibrinogen and other ligands. Ligand binding causes integrin clustering and subsequently promotes outside-in signaling, which initiates and amplifies a range of cellular events to drive essential platelet functions such as spreading, aggregation, clot retraction, and thrombus consolidation. Regulation of the bidirectional signaling of integrin αIIbβ3 requires the involvement of numerous interacting proteins, which associate with the cytoplasmic tails of αIIbβ3 in particular. Integrin αIIbβ3 and its signaling pathways are considered promising targets for antithrombotic therapy. This review describes the bidirectional signal transduction of integrin αIIbβ3 in platelets, as well as the proteins responsible for its regulation and therapeutic agents that target integrin αIIbβ3 and its signaling pathways.
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Affiliation(s)
- Jiansong Huang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xia Li
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaofeng Shi
- Department of Hematology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Mark Zhu
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jinghan Wang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shujuan Huang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xin Huang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Huafeng Wang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Department of Hematological Malignancies Translational Science, Gehr Family Center for Leukemia Research, Hematologic Malignancies and Stem Cell Transplantation Institute, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, 91010, USA
| | - Ling Li
- Department of Hematological Malignancies Translational Science, Gehr Family Center for Leukemia Research, Hematologic Malignancies and Stem Cell Transplantation Institute, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, 91010, USA
| | - Huan Deng
- Department of Pathology, The Fourth Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yulan Zhou
- Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Jianhua Mao
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Sino-French Research Centre for Life Sciences and Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhangbiao Long
- Department of Hematology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Zhixin Ma
- Clinical Prenatal Diagnosis Center, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Wenle Ye
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jiajia Pan
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaodong Xi
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Sino-French Research Centre for Life Sciences and Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jie Jin
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. .,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China. .,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
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14
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Abstract
In this issue of Blood, Hofmann et al and Geer et al describe signal-transducing properties of G6b-B that are required for normal platelet production by megakaryocytes in both humans and mice.1,2
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Stefanini L, Bergmeier W. Negative regulators of platelet activation and adhesion. J Thromb Haemost 2018; 16:220-230. [PMID: 29193689 PMCID: PMC5809258 DOI: 10.1111/jth.13910] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Indexed: 12/29/2022]
Abstract
Platelets are small anucleated cells that constantly patrol the cardiovascular system to preserve its integrity and prevent excessive blood loss where the vessel lining is breached. Their key challenge is to form a hemostatic plug under conditions of high shear forces. To do so, platelets have evolved a molecular machinery that enables them to sense trace amounts of signals at the site of damage and to rapidly shift from a non-adhesive to a pro-adhesive state. However, this highly efficient molecular machinery can also lead to unintended platelet activation and cause clinical complications such as thrombocytopenia and thrombosis. Thus, several checkpoints are in place to tightly control platelet activation and adhesiveness in space and time. In this review, we will discuss select negative regulators of platelet activation, which are critical to maintain patrolling platelets in a quiescent, non-adhesive state and/or to limit platelet adhesion to sites of injury.
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Affiliation(s)
- L Stefanini
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - W Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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16
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ITIM receptors: more than just inhibitors of platelet activation. Blood 2017; 129:3407-3418. [PMID: 28465343 DOI: 10.1182/blood-2016-12-720185] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/24/2017] [Indexed: 12/12/2022] Open
Abstract
Since their discovery, immunoreceptor tyrosine-based inhibition motif (ITIM)-containing receptors have been shown to inhibit signaling from immunoreceptor tyrosine-based activation motif (ITAM)-containing receptors in almost all hematopoietic cells, including platelets. However, a growing body of evidence has emerged demonstrating that this is an oversimplification, and that ITIM-containing receptors are versatile regulators of platelet signal transduction, with functions beyond inhibiting ITAM-mediated platelet activation. PECAM-1 was the first ITIM-containing receptor identified in platelets and appeared to conform to the established model of ITIM-mediated attenuation of ITAM-driven activation. PECAM-1 was therefore widely accepted as a major negative regulator of platelet activation and thrombosis for many years, but more recent findings suggest a more complex role for this receptor, including the facilitation of αIIbβ3-mediated platelet functions. Since the identification of PECAM-1, several other ITIM-containing platelet receptors have been discovered. These include G6b-B, a critical regulator of platelet reactivity and production, and the noncanonical ITIM-containing receptor TREM-like transcript-1, which is localized to α-granules in resting platelets, binds fibrinogen, and acts as a positive regulator of platelet activation. Despite structural similarities and shared binding partners, including the Src homology 2 domain-containing protein-tyrosine phosphatases Shp1 and Shp2, knockout and transgenic mouse models have revealed distinct phenotypes and nonredundant functions for each ITIM-containing receptor in the context of platelet homeostasis. These roles are likely influenced by receptor density, compartmentalization, and as-yet unknown binding partners. In this review, we discuss the diverse repertoire of ITIM-containing receptors in platelets, highlighting intriguing new functions, controversies, and future areas of investigation.
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17
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Unsworth AJ, Kriek N, Bye AP, Naran K, Sage T, Flora GD, Gibbins JM. PPARγ agonists negatively regulate αIIbβ3 integrin outside-in signaling and platelet function through up-regulation of protein kinase A activity. J Thromb Haemost 2017; 15:356-369. [PMID: 27896950 PMCID: PMC5396324 DOI: 10.1111/jth.13578] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Indexed: 12/31/2022]
Abstract
Essentials peroxisome proliferator-activated receptor γ (PPARγ) agonists inhibit platelet function. PPARγ agonists negatively regulate outside-in signaling via integrin αIIbβ3. PPARγ agonists disrupt the interaction of Gα13 with integrin β3. This is attributed to an upregulation of protein kinase A activity. SUMMARY Background Agonists for the peroxisome proliferator-activated receptor (PPARγ) have been shown to have inhibitory effects on platelet activity following stimulation by GPVI and GPCR agonists. Objectives Profound effects on thrombus formation led us to suspect a role for PPARγ agonists in the regulation of integrin αIIbβ3 mediated signaling. Both GPVI and GPCR signaling pathways lead to αIIbβ3 activation, and signaling through αIIbβ3 plays a critical role in platelet function and normal hemostasis. Methods The effects of PPARγ agonists on the regulation of αIIbβ3 outside-in signaling was determined by monitoring the ability of platelets to adhere and spread on fibrinogen and undergo clot retraction. Effects on signaling components downstream of αIIbβ3 activation were also determined following adhesion to fibrinogen by Western blotting. Results Treatment of platelets with PPARγ agonists inhibited platelet adhesion and spreading on fibrinogen and diminished clot retraction. A reduction in phosphorylation of several components of αIIbβ3 signaling, including the integrin β3 subunit, Syk, PLCγ2, focal adhesion kinase (FAK) and Akt, was also observed as a result of reduced interaction of the integrin β3 subunit with Gα13. Studies of VASP phosphorylation revealed that this was because of an increase in PKA activity following treatment with PPARγ receptor agonists. Conclusions This study provides further evidence for antiplatelet actions of PPARγ agonists, identifies a negative regulatory role for PPARγ agonists in the control of integrin αIIbβ3 outside-in signaling, and provides a molecular basis by which the PPARγ agonists negatively regulate platelet activation and thrombus formation.
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Affiliation(s)
- A. J. Unsworth
- Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingUK
| | - N. Kriek
- Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingUK
| | - A. P. Bye
- Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingUK
| | - K. Naran
- Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingUK
| | - T. Sage
- Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingUK
| | - G. D. Flora
- Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingUK
| | - J. M. Gibbins
- Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingUK
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18
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Melhem M, Abu-Farha M, Antony D, Madhoun AA, Bacchelli C, Alkayal F, AlKhairi I, John S, Alomari M, Beales PL, Alsmadi O. Novel G6B gene variant causes familial autosomal recessive thrombocytopenia and anemia. Eur J Haematol 2017; 98:218-227. [PMID: 27743390 DOI: 10.1111/ejh.12819] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2016] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To characterize the underlying genetic and molecular defects in a consanguineous family with lifelong blood disorder manifested with thrombocytopenia (low platelets count) and anemia. METHODS Genetic linkage analysis, exome sequencing, and functional genomics were carried out to identify and characterize the defective gene. RESULTS We identified a novel truncation mutation (p.C108*) in chromosome 6 open reading frame 25 (C6orf25) gene in this family. We also showed the p.C108* mutation was responsible for destabilizing the encoded truncated G6B protein. Unlike the truncated form, wild-type G6B expression resulted in enhanced K562 differentiation into megakaryocytes and erythrocytes. C6orf25, also known as G6B, is an effector protein for the key hematopoiesis regulators, Src homology region 2 domain-containing phosphatases SHP-1 and SHP-2. CONCLUSION G6B seems to act through an autosomal recessive mode of disease transmission in this family and regarded as the gene responsible for the observed hematological disorder. This inference is well supported further by in vivo evidence where similar outcomes were reported from G6b-/- and SHP1/2 DKO mouse models.
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Affiliation(s)
- Motasem Melhem
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Mohamed Abu-Farha
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Dinu Antony
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Ashraf Al Madhoun
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Chiara Bacchelli
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Fadi Alkayal
- Pancreatic Islet Biology & Transplantation Unit, Dasman Diabetes Institute, Dasman, Kuwait
| | - Irina AlKhairi
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Sumi John
- Integrative Informatics, Dasman Diabetes Institute, Dasman, Kuwait
| | - Mohamad Alomari
- Department of Pathology, Windsor Regional Hospital, Windsor, ON, Canada
| | - Phillip L Beales
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Osama Alsmadi
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
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19
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Unsworth AJ, Bye AP, Gibbins JM. Platelet-Derived Inhibitors of Platelet Activation. PLATELETS IN THROMBOTIC AND NON-THROMBOTIC DISORDERS 2017. [PMCID: PMC7123044 DOI: 10.1007/978-3-319-47462-5_37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Bye AP, Unsworth AJ, Gibbins JM. Platelet signaling: a complex interplay between inhibitory and activatory networks. J Thromb Haemost 2016; 14:918-30. [PMID: 26929147 PMCID: PMC4879507 DOI: 10.1111/jth.13302] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/11/2016] [Indexed: 01/22/2023]
Abstract
The role of platelets in hemostasis and thrombosis is dependent on a complex balance of activatory and inhibitory signaling pathways. Inhibitory signals released from the healthy vasculature suppress platelet activation in the absence of platelet receptor agonists. Activatory signals present at a site of injury initiate platelet activation and thrombus formation; subsequently, endogenous negative signaling regulators dampen activatory signals to control thrombus growth. Understanding the complex interplay between activatory and inhibitory signaling networks is an emerging challenge in the study of platelet biology, and necessitates a systematic approach to utilize experimental data effectively. In this review, we will explore the key points of platelet regulation and signaling that maintain platelets in a resting state, mediate activation to elicit thrombus formation, or provide negative feedback. Platelet signaling will be described in terms of key signaling molecules that are common to the pathways activated by platelet agonists and can be described as regulatory nodes for both positive and negative regulators.
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Affiliation(s)
- A P Bye
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK
| | - A J Unsworth
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK
| | - J M Gibbins
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK
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CEACAM2 negatively regulates hemi (ITAM-bearing) GPVI and CLEC-2 pathways and thrombus growth in vitro and in vivo. Blood 2014; 124:2431-41. [PMID: 25085348 DOI: 10.1182/blood-2014-04-569707] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Carcinoembryonic antigen-related cell adhesion molecule-2 (CEACAM2) is a cell-surface glycoprotein expressed on blood, epithelial, and vascular cells. CEACAM2 possesses adhesive and signaling properties mediated by immunoreceptor tyrosine-based inhibitory motifs. In this study, we demonstrate that CEACAM2 is expressed on the surface and in intracellular pools of platelets. Functional studies of platelets from Ceacam2(-/-)-deficient mice (Cc2(-/-)) revealed that CEACAM2 serves to negatively regulate collagen glycoprotein VI (platelet) (GPVI)-FcRγ-chain and the C-type lectinlike receptor 2 (CLEC-2) signaling. Cc2(-/-) platelets displayed enhanced GPVI and CLEC-2-selective ligands, collagen-related peptide (CRP), collagen, and rhodocytin (Rhod)-mediated platelet aggregation. They also exhibited increased adhesion on type I collagen, and hyperresponsive CRP and CLEC-2-induced α and dense granule release compared with wild-type platelets. Furthermore, using intravital microscopy to ferric chloride (FeCl3)-injured mesenteric arterioles and laser-induced injury of cremaster muscle arterioles, we herein show that thrombi formed in Cc2(-/-) mice were larger and more stable than wild-type controls in vivo. Thus, CEACAM2 is a novel platelet immunoreceptor that acts as a negative regulator of platelet GPVI-collagen interactions and of ITAM receptor CLEC-2 pathways.
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22
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Abstract
Murine paired immunoglobulin-like receptors B (PIRB), as the ortholog of human leukocyte immunoglobulin-like receptor B2 (LILRB2), is involved in a variety of biological functions. Here, we found that PIRB and LILRB2 were expressed in mouse and human platelets, respectively. PIRB intracellular domain deletion (PIRB-TM) mice had thrombocythemia and significantly higher proportions of megakaryocytes in bone marrow. Agonist-induced aggregation and spreading on immobilized fibrinogen were facilitated in PIRB-TM platelets. The rate of clot retraction in platelet-rich plasma containing PIRB-TM platelets was also increased. Characterization of signaling confirmed that PIRB associated with phosphatases Shp1/2 in platelets. The phosphorylation of Shp1/2 was significantly downregulated in PIRB-TM platelets stimulated with collagen-related peptide (CRP) or on spreading. The results further revealed that the phosphorylation levels of the linker for activation of T cells, SH2 domain-containing leukocyte protein of 76kDa, and phospholipase C were enhanced in PIRB-TM platelets stimulated with CRP. The phosphorylation levels of FAK Y397 and integrin β3 Y759 were also enhanced in PIRB-TM platelet spread on fibrinogen. The PIRB/LILRB2 ligand angiopoietin-like-protein 2 (ANGPTL2) was expressed and stored in platelet α-granules. ANGPTL2 inhibited agonist-induced platelet aggregation and spreading on fibrinogen. The data presented here reveal that PIRB and its ligand ANGPTL2 possess an antithrombotic function by suppressing collagen receptor glycoprotein VI and integrin αIIbβ3-mediated signaling.
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23
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Junctional adhesion molecule-A suppresses platelet integrin αIIbβ3 signaling by recruiting Csk to the integrin-c-Src complex. Blood 2013; 123:1393-402. [PMID: 24300854 DOI: 10.1182/blood-2013-04-496232] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Fibrinogen binding to activated integrin induces outside-in signaling that results in stable platelet aggregates and clot retraction. How integrin αIIbβ3 is discouraged from spontaneous activation is not known. We have recently shown that junctional adhesion molecule-A (JAM-A) renders protection from thrombosis by suppressing integrin outside-in signaling. In this study, we show that JAM-A associates with integrin αIIbβ3 in resting platelets and dissociates upon platelet activation by agonists. We also show that integrin-associated JAM-A is tyrosine phosphorylated and is rapidly dephosphorylated upon platelet activation. C-terminal Src kinase (Csk) binds to tyrosine phosphorylated JAM-A through its Src homology 2 domain. Thus, JAM-A recruits Csk to the integrin-c-Src complex in resting platelets. Csk, in turn, keeps integrin-associated c-Src in an inactive state by phosphorylating Y(529) in its regulatory domain. Absence of JAM-A results in impaired c-SrcY(529) phosphorylation and augmentation of outside-in signaling-dependent c-Src activation. Our results strongly suggest that tyrosine-phosphorylated JAM-A is a Csk-binding protein and functions as an endogenous inhibitor of integrin signaling. JAM-A recruits Csk to the integrin-c-Src complex, where Csk negatively regulates c-Src activation, thereby suppressing the initiation of outside-in signaling. Upon agonist stimulation, JAM-A is dephosphorylated on the tyrosine, allowing the dissociation of Csk from the integrin complex, and thus facilitating outside-in signaling.
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Schweigel H, Geiger J, Beck F, Buhs S, Gerull H, Walter U, Sickmann A, Nollau P. Deciphering of ADP-induced, phosphotyrosine-dependent signaling networks in human platelets by Src-homology 2 region (SH2)-profiling. Proteomics 2013; 13:1016-27. [PMID: 23322602 DOI: 10.1002/pmic.201200353] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 10/12/2012] [Accepted: 11/06/2012] [Indexed: 01/05/2023]
Abstract
Tyrosine phosphorylation plays a central role in signal transduction controlling many important biological processes. In platelets, the activity of several signaling proteins is controlled by tyrosine phosphorylation ensuring proper platelet activation and aggregation essential for regulation of the delicate balance between bleeding and hemostasis. Here, we applied Src-homology 2 region (SH2)-profiling for deciphering of the phosphotyrosine state of human platelets activated by adenosine diphosphate (ADP). Applying a panel of 31 SH2-domains, rapid and complex regulation of the phosphotyrosine state of platelets was observed after ADP stimulation. Specific inhibition of platelet P2Y receptors by synthetic drugs revealed a major role for the P2Y1 receptor in tyrosine phosphorylation. Concomitant activation of protein kinase A (PKA) abolished ADP-induced tyrosine phosphorylation in a time and concentration-dependent manner. Given the fact that PKA activity is negatively regulated by the P2Y12 receptor, our data provide evidence for a novel link of synergistic control of the state of tyrosine phosphorylation by both P2Y receptors. By SH2 domain pull down and MS/MS analysis, we identified distinct tyrosine phosphorylation sites in cell adhesion molecules, intracellular adapter proteins and phosphatases suggesting a major, functional role of tyrosine phosphorylation of theses candidate proteins in ADP-dependent signaling in human platelets.
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Affiliation(s)
- Hardy Schweigel
- Institute of Clinical Chemistry, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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25
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Aarnink A, Garchon HJ, Okada Y, Takahashi A, Matsuda K, Kubo M, Nakamura Y, Blancher A. Comparative analysis in cynomolgus macaque identifies a novel human MHC locus controlling platelet blood counts independently of BAK1. J Thromb Haemost 2013; 11:384-6. [PMID: 23217248 DOI: 10.1111/jth.12092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 11/11/2012] [Indexed: 11/28/2022]
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Coxon CH, Sadler AJ, Huo J, Campbell RD. An investigation of hierachical protein recruitment to the inhibitory platelet receptor, G6B-b. PLoS One 2012; 7:e49543. [PMID: 23185356 PMCID: PMC3501490 DOI: 10.1371/journal.pone.0049543] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 10/09/2012] [Indexed: 11/18/2022] Open
Abstract
Platelet activation is regulated by both positive and negative signals. G6B-b is an inhibitory platelet receptor with an immunoreceptor tyrosine-based inhibitory motif (ITIM) and an immunoreceptor tyrosine-based switch motif (ITSM). The molecular basis of inhibition by G6B-b is currently unknown but thought to involve the SH2 domain-containing tyrosine phosphatase SHP-1. Here we show that G6B-b also associates with SHP-2, as well as SHP-1, in human platelets. Using a number of biochemical approaches, we found these interactions to be direct and that the tandem SH2 domains of SHP-2 demonstrated a binding affinity for G6B-b 100-fold higher than that of SHP-1. It was also observed that while SHP-1 has an absolute requirement for phosphorylation at both motifs to bind, SHP-2 can associate with G6B-b when only one motif is phosphorylated, with the N-terminal SH2 domain and the ITIM being most important for the interaction. A number of other previously unreported SH2 domain-containing proteins, including Syk and PLCγ2, also demonstrated specificity for G6B-b phosphomotifs and may serve to explain the observation that G6B-b remains inhibitory in the absence of both SHP-1 and SHP-2. In addition, the presence of dual phosphorylated G6B-b in washed human platelets can reduce the EC(50) for both CRP and collagen.
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Affiliation(s)
- Carmen H. Coxon
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Amanda J. Sadler
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Jiandong Huo
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | - R. Duncan Campbell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Mazharian A, Wang YJ, Mori J, Bem D, Finney B, Heising S, Gissen P, White JG, Berndt MC, Gardiner EE, Nieswandt B, Douglas MR, Campbell RD, Watson SP, Senis YA. Mice lacking the ITIM-containing receptor G6b-B exhibit macrothrombocytopenia and aberrant platelet function. Sci Signal 2012; 5:ra78. [PMID: 23112346 PMCID: PMC4973664 DOI: 10.1126/scisignal.2002936] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Platelets are highly reactive cell fragments that adhere to exposed extracellular matrix (ECM) and prevent excessive blood loss by forming clots. Paradoxically, megakaryocytes, which produce platelets in the bone marrow, remain relatively refractory to the ECM-rich environment of the bone marrow despite having the same repertoire of receptors as platelets. These include the ITAM (immunoreceptor tyrosine-based activation motif)-containing collagen receptor complex, which consists of glycoprotein VI (GPVI) and the Fc receptor γ-chain, and the ITIM (immunoreceptor tyrosine-based inhibition motif)-containing receptor G6b-B. We showed that mice lacking G6b-B exhibited macrothrombocytopenia (reduced platelet numbers and the presence of enlarged platelets) and a susceptibility to bleeding as a result of aberrant platelet production and function. Platelet numbers were markedly reduced in G6b-B-deficient mice compared to those in wild-type mice because of increased platelet turnover. Furthermore, megakaryocytes in G6b-B-deficient mice showed enhanced metalloproteinase production, which led to increased shedding of cell-surface receptors, including GPVI and GPIbα. In addition, G6b-B-deficient megakaryocytes exhibited reduced integrin-mediated functions and defective formation of proplatelets, the long filamentous projections from which platelets bud off. Together, these findings establish G6b-B as a major inhibitory receptor regulating megakaryocyte activation, function, and platelet production.
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Affiliation(s)
- Alexandra Mazharian
- Centre of Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Ying-Jie Wang
- Centre of Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Jun Mori
- Centre of Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Danai Bem
- Centre of Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Brenda Finney
- Centre of Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Silke Heising
- Centre of Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Paul Gissen
- Department of Medical and Molecular Genetics, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham B15 2TT, UK
| | - James G. White
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael C. Berndt
- Biomedical Diagnostics Institute, Dublin City University and Royal College of Surgeons in Ireland, Glasnevin, Dublin 9, Ireland
| | - Elizabeth E. Gardiner
- Australian Centre for Blood Diseases, Monash University, Alfred Medical Research and Education Precinct, Melbourne, Victoria 3004, Australia
| | - Bernhard Nieswandt
- University Hospital and Rudolf Virchow Center, DFG Research Center for Experimental Biomedicine, University of Würzburg, Würzburg 97080, Germany
| | - Michael R. Douglas
- Neuropharmacology and Neurobiology Section, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham B15 2TT, UK
- Department of Neurology, Dudley Group of Hospitals NHS Foundation Trust, Dudley DY1 2HQ, UK
| | - Robert D. Campbell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Steve P. Watson
- Centre of Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Yotis A. Senis
- Centre of Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
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JAMming the signals. Blood 2012; 119:3197-8. [PMID: 22493215 DOI: 10.1182/blood-2012-02-409060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this issue of Blood, Naik and colleagues have identified a new mechanism used by platelets to inhibit the signals that drive their activation through integrin αIIbβ3,which serves to prevent inappropriate or premature thrombus formation.
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Jones CI, Barrett NE, Moraes LA, Gibbins JM, Jackson DE. Endogenous inhibitory mechanisms and the regulation of platelet function. Methods Mol Biol 2012; 788:341-66. [PMID: 22130718 DOI: 10.1007/978-1-61779-307-3_23] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The response of platelets to changes in the immediate environment is always a balance between activatory and inhibitory signals, the cumulative effect of which is either activation or quiescence. This is true of platelets in free flowing blood and of their regulation of haemostasis and thrombosis. In this review, we consider the endogenous inhibitory mechanisms that combine to regulate platelet activation. These include those derived from the endothelium (nitric oxide, prostacyclin, CD39), inhibitory receptors on the surface of platelets (platelet endothelial cell adhesion molecule-1, carcinoembryonic antigen cell adhesion molecule 1, G6b-B - including evidence for the role of Ig-ITIM superfamily members in the negative regulation of ITAM-associated GPVI platelet-collagen interactions and GPCR-mediated signalling and in positive regulation of "outside-in" integrin α(IIb)β(3)-mediated signalling), intracellular inhibitory receptors (retinoic X receptor, glucocorticoid receptor, peroxisome proliferator-activated receptors, liver X receptor), and emerging inhibitory pathways (canonical Wnt signalling, Semaphorin 3A, endothelial cell specific adhesion molecule, and junctional adhesion molecule-A).
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Affiliation(s)
- Chris I Jones
- Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, The University of Reading, Reading, UK
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Abstract
Platelets pose unique challenges to cell biologists due to their lack of nucleus and low levels of messenger RNA. Platelets cannot be cultured in great abundance or manipulated using common recombinant DNA technologies. As a result, platelet research has lagged behind that of nucleated cells. The advent of mass spectrometry and its application to protein biochemistry brought with it great hopes for the platelet community that are now being realized. This technology is ideally suited for identifying low-abundance proteins, protein-protein interactions, and post-translational modifications in complex protein mixtures. Over the past 10 years, proteomics has delivered in many ways, providing platelet biologists with a comprehensive list of proteins expressed in platelets, information on post-translational modifications, protein interactions and sub-cellular localization. Several novel and important platelet membrane proteins, including CLEC-2, CD148, G6b-B, G6f, and Hsp47, have been identified using proteomics-based approaches. New, more sensitive instrumentation and novel approaches are making it increasingly possible to identify ever lower amounts of proteins. In this chapter we highlight some of the major achievements of platelet proteomics to date, discussing challenges and how they were overcome. We also discuss new frontiers and applications of proteomics to platelets and microparticles in health and disease, as we strive to better understand the molecular mechanisms underlying the platelet response to vascular injury.
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Affiliation(s)
- Yotis Senis
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK.
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Abstract
Atherothrombosis often underlies coronary artery disease, stroke, and peripheral arterial disease. Antiplatelet drugs have come to the forefront of prophylactic treatment of atherothrombotic disease. Dual antiplatelet therapy of aspirin plus clopidogrel-the current standard-has benefits, but it also has limitations with regard to pharmacologic properties and adverse effects with often severe bleeding complications. For these reasons, within the last decade or so, the investigation of novel antiplatelet targets has prospered. Target identification can be the result of large-scale genomic or proteomic studies, functional genomics in animal models, the genetic analysis of patients with inherited bleeding disorders, or a combination of these techniques.
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Suzuki-Inoue K, Inoue O, Ozaki Y. Novel platelet activation receptor CLEC-2: from discovery to prospects. J Thromb Haemost 2011; 9 Suppl 1:44-55. [PMID: 21781241 DOI: 10.1111/j.1538-7836.2011.04335.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
C-type lectin-like receptor 2 (CLEC-2) has been identified as a receptor for the platelet activating snake venom rhodocytin. CLEC-2 elicits powerful platelet activation signals in conjunction with Src, Syk kinases, and phospholipase Cγ2, similar to the collagen receptor glycoprotein (GP) VI/FcRγ-chain complex. In contrast to GPVI/FcRγ, which initiates platelet activation through the tandem YxxL motif immunoreceptor tyrosine-based activation motif (ITAM), CLEC-2 signals via the single YxxL motif hemi-ITAM. The endogenous ligand of CLEC-2 has been identified as podoplanin, which is expressed on the surface of tumour cells and facilitates tumour metastasis by inducing platelet activation. Studies of CLEC-2-deficient mice have revealed several physiological roles of CLEC-2. Podoplanin is also expressed in lymphatic endothelial cells as well as several other cells, including type I alveolar cells and kidney podocytes, but is absent from vascular endothelial cells. In the developmental stages, when the primary lymph sac is derived from the cardinal vein, podoplanin activates platelets in lymphatic endothelial cells by binding to CLEC-2, which facilitates blood/lymphatic vessel separation. Moreover, CLEC-2 is involved in thrombus stabilisation under flow conditions in part through homophilic interactions. However, the absence of CLEC-2 does not significantly increase bleeding tendency. CLEC-2 may be a good target protein for novel anti-platelet drugs or anti-metastatic drugs having therapeutic and preventive effects on arterial thrombosis and cancer, the primary causes of mortality in developed countries. In this article, we review the mechanisms of signal transduction, structure, expression, and function of CLEC-2.
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Affiliation(s)
- K Suzuki-Inoue
- Department of Clinical and Laboratory Medicine, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan
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35
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Platelet receptor signaling in thrombus formation. J Mol Med (Berl) 2010; 89:109-21. [DOI: 10.1007/s00109-010-0691-5] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 09/27/2010] [Accepted: 10/08/2010] [Indexed: 01/09/2023]
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Transcription profiling in human platelets reveals LRRFIP1 as a novel protein regulating platelet function. Blood 2010; 116:4646-56. [PMID: 20833976 DOI: 10.1182/blood-2010-04-280925] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Within the healthy population, there is substantial, heritable, and interindividual variability in the platelet response. We explored whether a proportion of this variability could be accounted for by interindividual variation in gene expression. Through a correlative analysis of genome-wide platelet RNA expression data from 37 subjects representing the normal range of platelet responsiveness within a cohort of 500 subjects, we identified 63 genes in which transcript levels correlated with variation in the platelet response to adenosine diphosphate and/or the collagen-mimetic peptide, cross-linked collagen-related peptide. Many of these encode proteins with no reported function in platelets. An association study of 6 of the 63 genes in 4235 cases and 6379 controls showed a putative association with myocardial infarction for COMMD7 (COMM domain-containing protein 7) and a major deviation from the null hypo thesis for LRRFIP1 [leucine-rich repeat (in FLII) interacting protein 1]. Morpholino-based silencing in Danio rerio identified a modest role for commd7 and a significant effect for lrrfip1 as positive regulators of thrombus formation. Proteomic analysis of human platelet LRRFIP1-interacting proteins indicated that LRRFIP1 functions as a component of the platelet cytoskeleton, where it interacts with the actin-remodeling proteins Flightless-1 and Drebrin. Taken together, these data reveal novel proteins regulating the platelet response.
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Abstract
SUMMARY The glycoprotein VI (GPVI)-FcR gamma-chain complex initiates powerful activation of platelets by the subendothelial matrix proteins collagen and laminin through an immunoreceptor tyrosine-based activation motif (ITAM)-regulated signaling pathway. ITAMs are characterized by two YxxL sequences separated by 6-12 amino acids and are found associated with several classes of immunoglobulin (Ig) and C-type lectin receptors in hematopoietic cells, including Fc receptors. Cross-linking of the Ig GPVI leads to phosphorylation of two conserved tyrosines in the FcR gamma-chain ITAM by Src family tyrosine kinases, followed by binding and activation of the tandem SH2 domain-containing Syk tyrosine kinase and stimulation of a downstream signaling cascade that culminates in activation of phospholipase Cgamma2 (PLCgamma2). In contrast, the C-type lectin receptor CLEC-2 mediates powerful platelet activation through Src and Syk kinases, but regulates Syk through a novel dimerization mechanism via a single YxxL motif known as a hemITAM. CLEC-2 is a receptor for podoplanin, which is expressed at high levels in several tissues, including type 1 lung alveolar cells, lymphatic endothelial cells, kidney podocytes and some tumors, but is absent from vascular endothelial cells and platelets. In this article, we compare the mechanism of platelet activation by GPVI and CLEC-2 and consider their functional roles in hemostasis and other vascular processes, including maintenance of vascular integrity, angiogenesis and lymphogenesis.
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Affiliation(s)
- S P Watson
- Centre for Cardiovascular Sciences, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
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38
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Tucker KL, Kaiser WJ, Bergeron AL, Hu H, Dong JF, Tan TH, Gibbins JM. Proteomic analysis of resting and thrombin-stimulated platelets reveals the translocation and functional relevance of HIP-55 in platelets. Proteomics 2009; 9:4340-54. [PMID: 19725075 DOI: 10.1002/pmic.200900024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The platelet surface is a dynamic interface that changes rapidly in response to stimuli to co-ordinate the formation of thrombi at sites of vascular injury. Tight control is essential as loss of organisation may result in the inappropriate formation of thrombi (thrombosis) or excessive bleeding. In this paper we describe the comparative analysis of resting and thrombin-stimulated platelet membrane proteomes and associated proteins to identify proteins important to platelet function. Surface proteins were labelled using a biotin tag and isolated by NeurtrAvidin affinity chromatography. Liquid phase IEF and SDS-PAGE were used to separate proteins, and bands of increased intensity in the stimulated platelet fractions were digested and identified by FT-ICR mass spectrometry. Novel proteins were identified along with proteins known to be translocated to the platelet surface. Furthermore, many platelet proteins revealed changes in location associated with function, including G6B and Hip-55. HIP-55 is an SH3-binding protein important in T-cell receptor signalling. Further analysis of HIP-55 revealed that this adaptor protein becomes increasingly associated with both Syk and integrin beta3 upon platelet activation. Analysis of HIP-55 deficient platelets revealed reduced fibrinogen binding upon thrombin stimulation, suggesting HIP-55 to be an important regulator of platelet function.
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Affiliation(s)
- Katherine L Tucker
- Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, The University of Reading, Whiteknights, Reading, UK.
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39
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Stalker TJ, Wu J, Morgans A, Traxler EA, Wang L, Chatterjee MS, Lee D, Quertermous T, Hall RA, Hammer DA, Diamond SL, Brass LF. Endothelial cell specific adhesion molecule (ESAM) localizes to platelet-platelet contacts and regulates thrombus formation in vivo. J Thromb Haemost 2009; 7:1886-96. [PMID: 19740102 PMCID: PMC4441405 DOI: 10.1111/j.1538-7836.2009.03606.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND In resting platelets, endothelial cell specific adhesion molecule (ESAM) is located in alpha granules, increasing its cell surface expression following platelet activation. However, the function of ESAM on platelets is unknown. OBJECTIVE To determine whether ESAM has a role in thrombus formation. METHODS AND RESULTS We found that following platelet activation ESAM localizes to the junctions between adjacent platelets, suggesting a role for this protein in contact-dependent events that regulate thrombus formation. To test this hypothesis we examined the effect of ESAM deletion on platelet function. In vivo, ESAM(-/-) mice achieved more stable hemostasis than wild-type mice following tail transection, and developed larger thrombi following laser injury of cremaster muscle arterioles. In vitro, ESAM(-/-) platelets aggregated at lower concentrations of G protein-dependent agonists than wild-type platelets, and were more resistant to disaggregation. In contrast, agonist-induced calcium mobilization, alpha(IIb)beta(3) activation, alpha-granule secretion and platelet spreading, were normal in ESAM-deficient platelets. To understand the molecular mechanism by which ESAM regulates platelet activity, we utilized a PDZ domain array to identify the scaffold protein NHERF-1 as an ESAM binding protein, and further demonstrated that it associates with ESAM in both resting and activated platelets. CONCLUSIONS These findings support a model in which ESAM localizes to platelet contacts following platelet activation in order to limit thrombus growth and stability so that the optimal hemostatic response occurs following vascular injury.
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Affiliation(s)
- T J Stalker
- Department of Medicine, The Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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40
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Kleiman NS, Freedman JE, Tracy PB, Furie BC, Bray PF, Rao SV, Phillips DR, Storey RF, Rusconi CP, French PA, Steinhubl SR, Becker RC. Platelets: Developmental biology, physiology, and translatable platforms for preclinical investigation and drug development. Platelets 2009; 19:239-51. [DOI: 10.1080/09537100801947442] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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41
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Abstract
Members of the Src family of protein tyrosine kinases play important roles in platelet adhesion, activation, and aggregation. The purpose of this review is to summarize current knowledge regarding how Src family kinase activity is regulated in general, to describe what is known about mechanisms underlying SFK activation in platelets, and to discuss platelet proteins that contribute to SFK inactivation, particularly those that use phosphotyrosine-containing sequences to recruit phosphatases and kinases to sites of SFK activity.
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Affiliation(s)
- D K Newman
- Blood Center of Wisconsin, Blood Research Institute, Milwaukee, WI 53226, USA.
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42
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The low-frequency isoform of platelet glycoprotein VIb attenuates ligand-mediated signal transduction but not receptor expression or ligand binding. Blood 2009; 114:1893-9. [PMID: 19465689 DOI: 10.1182/blood-2009-03-209510] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 2 most common haplotypes of human GP6, GP6a and GP6b, generate the allelic isoforms glycoprotein VI (GPVI)a and GPVIb that differ by 5 amino acids: S219P, K237E, and T249A in the ectodomains, and Q317L and H322N in the cytoplasmic domain. By quantitative Western blot, we found no association between GP6 genotype and total platelet GPVI content among 132 normal subjects. When expressed as soluble products or as membrane-associated receptors, GPVIa and GPVIb have identical affinities for type I collagen, collagen-related peptide, or convulxin. However, the cytoplasmic domain substitutions in GPVIb have a significant effect on GPVI-dependent subcellular associations and ligand-induced signal transduction. L317 increases binding to calmodulin, whereas N322 attenuates binding to Fyn/Lyn. Consistent with the latter finding, convulxin-induced Syk phosphorylation is significantly attenuated in Dami cells stably transfected with GPVIb, relative to GPVIa. This represents direct evidence that haplotype-related GPVI functional differences are inherent in the cytoplasmic domain substitutions, whereby GPVIb binds less strongly to Fyn/Lyn and attenuates the rate and extent of Syk phosphorylation. These allelic differences in GP6a and GP6b explain functional differences in the respective isoforms, but the molecular basis for the several-fold range in GPVI levels of human platelets remains to be determined.
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43
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Power KA, McRedmond JP, de Stefani A, Gallagher WM, Ó Gaora P. High-throughput proteomics detection of novel splice isoforms in human platelets. PLoS One 2009; 4:e5001. [PMID: 19308253 PMCID: PMC2654914 DOI: 10.1371/journal.pone.0005001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Accepted: 02/20/2009] [Indexed: 12/16/2022] Open
Abstract
Alternative splicing (AS) is an intrinsic regulatory mechanism of all metazoans. Recent findings suggest that 100% of multiexonic human genes give rise to splice isoforms. AS can be specific to tissue type, environment or developmentally regulated. Splice variants have also been implicated in various diseases including cancer. Detection of these variants will enhance our understanding of the complexity of the human genome and provide disease-specific and prognostic biomarkers. We adopted a proteomics approach to identify exon skip events - the most common form of AS. We constructed a database harboring the peptide sequences derived from all hypothetical exon skip junctions in the human genome. Searching tandem mass spectrometry (MS/MS) data against the database allows the detection of exon skip events, directly at the protein level. Here we describe the application of this approach to human platelets, including the mRNA-based verification of novel splice isoforms of ITGA2, NPEPPS and FH. This methodology is applicable to all new or existing MS/MS datasets.
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Affiliation(s)
- Karen A. Power
- UCD Conway Institute and UCD School of Biomolecular & Biomedical Sciences, UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - James P. McRedmond
- UCD Conway Institute and UCD School of Biomolecular & Biomedical Sciences, UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | | | - William M. Gallagher
- UCD Conway Institute and UCD School of Biomolecular & Biomedical Sciences, UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Peadar Ó Gaora
- UCD Conway Institute and UCD School of Medicine & Medical Sciences, UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland
- * E-mail:
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44
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CEACAM1 negatively regulates platelet-collagen interactions and thrombus growth in vitro and in vivo. Blood 2009; 113:1818-28. [DOI: 10.1182/blood-2008-06-165043] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Abstract
Carcinoembryonic antigen cell adhesion molecule-1 (CEACAM1) is a surface glycoprotein expressed on various blood cells, epithelial cells, and vascular cells. CEACAM1 possesses adhesive and signaling properties mediated by its intrinsic immunoreceptor tyrosine-based inhibitory motifs that recruit SHP-1 protein-tyrosine phosphatase. In this study, we demonstrate that CEACAM1 is expressed on the surface and in intracellular pools of platelets. In addition, CEACAM1 serves to negatively regulate signaling of platelets by collagen through the glycoprotein VI (GPVI)/Fc receptor (FcR)–γ-chain. ceacam1−/− platelets displayed enhanced type I collagen and GPVI-selective ligand, collagen-related peptide (CRP), CRP-mediated platelet aggregation, enhanced platelet adhesion on type I collagen, and elevated CRP-mediated alpha and dense granule secretion. Platelets derived from ceacam1−/− mice form larger thrombi when perfused over a collagen matrix under arterial flow compared with wild-type mice. Furthermore, using intravital microscopy to ferric chloride-injured mesenteric arterioles, we show that thrombi formed in vivo in ceacam1−/− mice were larger and were more stable than those in wild-type mice. GPVI depletion using monoclonal antibody JAQ1 treatment of ceacam1−/− mice showed a reversal in the more stable thrombus growth phenotype. ceacam1−/− mice were more susceptible to type I collagen–induced pulmonary thromboembolism than wild-type mice. Thus, CEACAM1 acts as a negative regulator of platelet-collagen interactions and of thrombus growth involving the collagen GPVI receptor in vitro and in vivo.
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Ollivier V, Arnaud B, Jandrot-Perrus M, Ajzenberg N. Monocytes downregulate the early stage of collagen-induced platelet activation by a PECAM-1-dependent mechanism. J Thromb Haemost 2009; 7:143-51. [PMID: 18983521 DOI: 10.1111/j.1538-7836.2008.03170.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Blood vessel damage results in exposure of the subendothelial matrix, to which platelets adhere. Monocytes are recruited and activated at the site of injury. OBJECTIVES Here we studied the effect of monocytes on platelet activation induced by exposure to fibrillar collagen. METHODS Washed platelets and isolated monocytes (100/1) were coincubated with type I collagen in static adhesion conditions or in suspension. Platelet activation was assessed by measuring RANTES production and alpha-granule secretion. Platelet adherence on immobilized collagen was analyzed by fluorescence confocal microscopy. Cell-cell contacts were prevented by incubating platelets and monocytes in transwell coculture dishes. Experiments were also performed in the presence of soluble recombinant platelet endothelial cell adhesion molecule-1 (PECAM-1) or of antibodies to PECAM-1. RESULTS Unexpectedly, unstimulated monocytes limited the initial phase of platelet activation by fibrillar collagen. In adhesion conditions, monocytes reduced the secretion by platelets of the inflammatory chemokine RANTES and of beta-thromboglobulin and the formation of platelet aggregates. The inhibitory effect of monocytes on platelet activation required direct cell-cell contacts between platelets and monocytes. Monocytes also inhibited collagen-induced platelet activation in suspension conditions as assessed by the reduction of P-selectin exposure and RANTES secretion. A recovery of platelet responses was observed in the presence of soluble PECAM-1 and of PECAM-1.3 Fab, indicating that PECAM-1 is involved in monocyte-triggered downregulation of platelet reactivity. CONCLUSIONS Our data provide the first evidence that unstimulated monocytes limit the initial phase of platelet activation by collagen via a mechanism that is, at least in part, PECAM-1-dependent.
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Affiliation(s)
- V Ollivier
- Inserm, U698, Paris, F-75018, AP-HP, Hôpital Bichat, Department of Haematology, CIB PhenoGen, University Paris7-Denis Diderot, Paris, France
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Korporaal SJA, Koekman CA, Verhoef S, van der Wal DE, Bezemer M, Van Eck M, Akkerman JWN. Downregulation of platelet responsiveness upon contact with LDL by the protein-tyrosine phosphatases SHP-1 and SHP-2. Arterioscler Thromb Vasc Biol 2008; 29:372-9. [PMID: 19096001 DOI: 10.1161/atvbaha.108.173278] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The sensitivity of platelets to aggregating agents increases when low-density lipoprotein (LDL) binds to apolipoprotein E receptor 2' (apoER2'), triggering activation of p38MAPK and formation of thromboxane A2. LDL signaling is terminated by PECAM-1 through recruitment and activation of the Ser/Thr protein phosphatase PP2A, but platelets remain unresponsive to LDL when PECAM-1 activation disappears. We report a second mechanism that halts LDL signaling and in addition lowers platelet responsiveness to aggregating agents. METHODS AND RESULTS After a first stimulation with LDL, platelets remain unresponsive to LDL for 60 minutes, despite normal apoER2' activation by a second dose of LDL. A possible cause is persistent activation of the tyrosine phosphatases SHP-1 and SHP-2, which may not only block a second activation of p38MAPK, PECAM-1, and PP2A by LDL but also seem to reduce aggregation by TRAP, collagen, and ADP. CONCLUSION These findings reveal that p38MAPK phosphorylation and platelet activation by LDL are suppressed by two mechanisms: (1) short activation of PECAM-1/PP2A, and (2) prolonged activation of SHP-1 and SHP-2. Activation of SHP-1 and SHP-2 is accompanied by reduced responsiveness to aggregating agents, which--if present in vivo--would make LDL an aggregation inhibitor during prolonged contact with platelets.
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Affiliation(s)
- Suzanne J A Korporaal
- Department of Clinical Chemistry and Haematology, University Medical Center, Utrecht, The Netherlands
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Mori J, Pearce AC, Spalton JC, Grygielska B, Eble JA, Tomlinson MG, Senis YA, Watson SP. G6b-B inhibits constitutive and agonist-induced signaling by glycoprotein VI and CLEC-2. J Biol Chem 2008; 283:35419-27. [PMID: 18955485 PMCID: PMC2602894 DOI: 10.1074/jbc.m806895200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Platelets play an essential role in wound healing by forming thrombi that
plug holes in the walls of damaged blood vessels. To achieve this, platelets
express a diverse array of cell surface receptors and signaling proteins that
induce rapid platelet activation. In this study we show that two platelet
glycoprotein receptors that signal via an immunoreceptor tyrosine-based
activation motif (ITAM) or an ITAM-like domain, namely the collagen receptor
complex glycoprotein VI (GPVI)-FcR γ-chain and the C-type lectin-like
receptor 2 (CLEC-2), respectively, support constitutive (i.e.
agonist-independent) signaling in a cell line model using a nuclear factor of
activated T-cells (NFAT) transcriptional reporter assay that can detect low
level activation of phospholipase Cγ (PLCγ). Constitutive and
agonist signaling by both receptors is dependent on Src and Syk family
kinases, and is inhibited by G6b-B, a platelet immunoglobulin receptor that
has two immunoreceptor tyrosine-based inhibitory motifs in its cytosolic tail.
Mutation of the conserved tyrosines in the two immunoreceptor tyrosine-based
inhibitory motifs prevents the inhibitory action of G6b-B. Interestingly, the
inhibitory activity of G6b-B is independent of the Src homology 2 (SH2)-domain
containing tyrosine phosphatases, SHP1 and SHP2, and the inositol
5′-phosphatase, SHIP. Constitutive signaling via Src and Syk tyrosine
kinases is observed in platelets and is associated with tyrosine
phosphorylation of GPVI-FcR γ-chain and CLEC-2. We speculate that
inhibition of constitutive signaling through Src and Syk tyrosine kinases by
G6b-B may help to prevent unwanted platelet activation.
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Affiliation(s)
- Jun Mori
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, B15 2TT, UK
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48
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Barrett NE, Holbrook L, Jones S, Kaiser WJ, Moraes LA, Rana R, Sage T, Stanley RG, Tucker KL, Wright B, Gibbins JM. Future innovations in anti-platelet therapies. Br J Pharmacol 2008; 154:918-39. [PMID: 18587441 PMCID: PMC2451055 DOI: 10.1038/bjp.2008.151] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 03/31/2008] [Accepted: 03/31/2008] [Indexed: 12/15/2022] Open
Abstract
Platelets have long been recognized to be of central importance in haemostasis, but their participation in pathological conditions such as thrombosis, atherosclerosis and inflammation is now also well established. The platelet has therefore become a key target in therapies to combat cardiovascular disease. Anti-platelet therapies are used widely, but current approaches lack efficacy in a proportion of patients, and are associated with side effects including problem bleeding. In the last decade, substantial progress has been made in understanding the regulation of platelet function, including the characterization of new ligands, platelet-specific receptors and cell signalling pathways. It is anticipated this progress will impact positively on the future innovations towards more effective and safer anti-platelet agents. In this review, the mechanisms of platelet regulation and current anti-platelet therapies are introduced, and strong, and some more speculative, potential candidate target molecules for future anti-platelet drug development are discussed.
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Affiliation(s)
- N E Barrett
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - L Holbrook
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - S Jones
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - W J Kaiser
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - L A Moraes
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - R Rana
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - T Sage
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - R G Stanley
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - K L Tucker
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - B Wright
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
| | - J M Gibbins
- School of Biological Sciences, University of Reading, Whiteknights, Reading Berkshire, UK
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49
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Zahedi RP, Lewandrowski U, Wiesner J, Wortelkamp S, Moebius J, Schütz C, Walter U, Gambaryan S, Sickmann A. Phosphoproteome of resting human platelets. J Proteome Res 2007; 7:526-34. [PMID: 18088087 DOI: 10.1021/pr0704130] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Beside their main physiological function in hemostasis, platelets are also highly involved in pathological processes, such as atherothrombosis and inflammation. During hemostasis, binding of adhesive substrates to tyrosine-kinase-linked adhesion receptors and/or soluble agonists to G-protein coupled receptors leads to a cascade of intracellular signaling processes based on substrate (de)phosphorylation. The same mechanisms are involved in platelet activation at sites of atherosclerotic plaque rupture, contributing to vessel occlusion and consequently to pathologic states, such as myocardial infarction, stroke, or peripheral artery disease. To gain a deeper insight into platelet function, we analyzed the phosphoproteome of resting platelets and identified 564 phosphorylation sites from more than 270 proteins, of which many have not been described in platelets before. Among those were several unknown potential protein kinase A (PKA) and protein kinase G (PKG) substrates. Because platelet inhibition is tightly regulated especially by PKA and PKG activity, these proteins may represent important new targets for cardiovascular research. Thus, our finding that GPIbalpha is phosphorylated at Ser603 in resting platelets may represent a novel mechanism for the regulation of one of the most important platelet receptor (GPIb-IX-V) mediated signaling pathways by PKA/PKG.
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Affiliation(s)
- René P Zahedi
- Rudolf Virchow Center/DFG Research Center for Experimental Biomedicine, University of Würzburg, Protein Mass Spectrometry and Functional Proteomics Group, Würzburg, D-97078 Germany
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50
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Abstract
Platelets play a pivotal role in atherothrombosis after coronary artery plaque rupture. The extent of response of platelets to such an event varies between individuals. This variation is for a large extent genetically controlled. A comprehensive study of sequence variation that modifies the platelet response to agonists is, however, lacking. We set out to discover the regulatory nodes of platelet function by an integrated systems biology approach. The high density genotyping of 110 genes in a cohort of more than 500 individuals, in whom the platelet response to ADP and collagen-related peptide was determined, allowed the robust definition of the first set of regulatory nodes. Microarray and proteomics studies on platelets from individuals with a so-called 'extreme end' response phenotype provided further insight into key regulators of platelet function. In addition, the completion of the HapMap project allows the comprehensive surveying of the genome for sequence variation by the testing of a limited number of single nucleotide polymorphisms (SNPs). With the advent of high density (i.e. 500,000 SNPs) genotyping arrays large number of case and control samples can be tested at an affordable cost. The recently completed Wellcome Trust Case Control Consortium (WTCCC) study has allowed us to address the question of whether common sequence variation confers risk for seven common diseases, one being myocardial infarction. The results of the WTCCC genome-wide association study and issues of case-control study design, particularly the selection of suitable controls, will be reviewed. In conclusion the integration of the results from the platelet systems biology study with those of the WTCCC project enhances our understanding of the mechanisms underlying common conditions such as atherothrombosis and provides pointers to novel cellular mechanisms and pathways.
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Affiliation(s)
- W H Ouwehand
- Department of Haematology, University of Cambridge and National Health Service Blood and Transplant, Cambridge, UK.
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