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Moon MJ, Rai A, Sharma P, Fang H, McFadyen JD, Greening DW, Peter K. Differential effects of physiological agonists on the proteome of platelet-derived extracellular vesicles. Proteomics 2024; 24:e2300391. [PMID: 38556629 DOI: 10.1002/pmic.202300391] [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: 10/17/2023] [Revised: 03/12/2024] [Accepted: 03/15/2024] [Indexed: 04/02/2024]
Abstract
Arterial thrombosis manifesting as heart attack and stroke is the leading cause of death worldwide. Platelets are central mediators of thrombosis that can be activated through multiple activation pathways. Platelet-derived extracellular vesicles (pEVs), also known as platelet-derived microparticles, are granular mixtures of membrane structures produced by platelets in response to various activating stimuli. Initial studies have attracted interest on how platelet agonists influence the composition of the pEV proteome. In the current study, we used physiological platelet agonists of varying potencies which reflect the microenvironments that platelets experience during thrombus formation: adenosine diphosphate, collagen, thrombin as well as a combination of thrombin/collagen to induce platelet activation and pEV generation. Proteomic profiling revealed that pEVs have an agonist-dependent altered proteome in comparison to their cells of origin, activated platelets. Furthermore, we found that various protein classes including those related to coagulation and complement (prothrombin, antithrombin, and plasminogen) and platelet activation (fibrinogen) are attributed to platelet EVs following agonist stimulation. This agonist-dependent altered proteome suggests that protein packaging is an active process that appears to occur without de novo protein synthesis. This study provides new information on the influence of physiological agonist stimuli on the biogenesis and proteome landscape of pEVs.
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Affiliation(s)
- Mitchell J Moon
- Department of Cardiometabolic Health, University of Melbourne, Melbourne, Victoria, Australia
- Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Alin Rai
- Department of Cardiometabolic Health, University of Melbourne, Melbourne, Victoria, Australia
- Molecular Proteomics, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Baker Department of Cardiovascular Research, Translation and Implementation, La Trobe University, Melbourne, Victoria, Australia
| | - Prerna Sharma
- Department of Cardiometabolic Health, University of Melbourne, Melbourne, Victoria, Australia
- Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Haoyun Fang
- Department of Cardiometabolic Health, University of Melbourne, Melbourne, Victoria, Australia
- Molecular Proteomics, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - James D McFadyen
- Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Department of Haematology, Alfred Hospital, Melbourne, Victoria, Australia
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - David W Greening
- Department of Cardiometabolic Health, University of Melbourne, Melbourne, Victoria, Australia
- Molecular Proteomics, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Baker Department of Cardiovascular Research, Translation and Implementation, La Trobe University, Melbourne, Victoria, Australia
| | - Karlheinz Peter
- Department of Cardiometabolic Health, University of Melbourne, Melbourne, Victoria, Australia
- Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Baker Department of Cardiovascular Research, Translation and Implementation, La Trobe University, Melbourne, Victoria, Australia
- Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia
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2
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Edwards ESJ, Ojaimi S, Ngui J, Seo GH, Kim J, Chunilal S, Yablonski D, O'Hehir RE, van Zelm MC. Combined immunodeficiency and impaired PI3K signaling in a patient with biallelic LCP2 variants. J Allergy Clin Immunol 2023; 152:807-813.e7. [PMID: 37211057 DOI: 10.1016/j.jaci.2023.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 04/25/2023] [Accepted: 04/28/2023] [Indexed: 05/23/2023]
Abstract
BACKGROUND Inborn errors affecting components of the T-cell receptor signaling cascade cause combined immunodeficiency with various degrees of severity. Recently, homozygous variants in LCP2 were reported to cause pediatric onset of severe combined immunodeficiency with neutrophil, platelet, and T- and B-cell defects. OBJECTIVE We sought to unravel the genetic cause of combined immunodeficiency and early-onset immune dysregulation in a 26-year-old man who presented with specific antibody deficiency, autoimmunity, and inflammatory bowel disease since early childhood. METHODS The patient was subjected to whole-exome sequencing of genomic DNA and examination of blood neutrophils, platelets, and T and B cells. Expression levels of the Src homology domain 2-containing leukocyte protein of 76 kDa (SLP76) and tonic and ligand-induced PI3K signaling were evaluated by flow-cytometric detection of phosphorylated ribosomal protein S6 in B and T cells. RESULTS Compound heterozygous missense variants were identified in LCP2, affecting the proline-rich repeat domain of SLP76 (p.P190R and p.R204W). The patient's total B- and T-cell numbers were within the normal range, as was platelet function. However, neutrophil function, numbers of unswitched and class-switched memory B cells, and serum IgA were decreased. Moreover, intracellular SLP76 protein levels were reduced in the patient's B cells, CD4+ and CD8+ T cells, and natural killer cells. Tonic and ligand-induced levels of phosphorylated ribosomal protein S6 and ligand-induced phosphorylated PLCγ1 were decreased in the patient's B cells and CD4+ and CD8+ T cells. CONCLUSIONS Biallelic variants in LCP2 impair neutrophil function and T-cell and B-cell antigen-receptor signaling and can cause combined immunodeficiency with early-onset immune dysregulation, even in the absence of platelet defects.
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Affiliation(s)
- Emily S J Edwards
- Allergy and Clinical Immunology Laboratory, Department of Immunology, Central Clinical School, Monash University, Melbourne, Australia; Jeffrey Modell Diagnostic and Research Centre for Primary Immunodeficiencies, Melbourne, Australia
| | - Samar Ojaimi
- Jeffrey Modell Diagnostic and Research Centre for Primary Immunodeficiencies, Melbourne, Australia; Monash Pathology, Monash Health, Melbourne, Australia; Monash Infectious Diseases, Monash Health, Melbourne, Australia; Monash Lung Sleep Allergy Immunology, Monash Health, Melbourne, Australia; Department of Medicine, Southern Clinical School, Monash Health and Monash University, Melbourne, Australia.
| | - James Ngui
- Monash Pathology, Monash Health, Melbourne, Australia
| | - Go Hun Seo
- Division of Medical Genetics, 3billion Inc, Seoul, Korea
| | - JiHye Kim
- Division of Medical Genetics, 3billion Inc, Seoul, Korea
| | - Sanjeev Chunilal
- Department of Pathology and Radiology, Monash Health, Melbourne, Australia
| | - Deborah Yablonski
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Robyn E O'Hehir
- Allergy and Clinical Immunology Laboratory, Department of Immunology, Central Clinical School, Monash University, Melbourne, Australia; Jeffrey Modell Diagnostic and Research Centre for Primary Immunodeficiencies, Melbourne, Australia; Department of Allergy, Immunology and Respiratory Medicine, Central Clinical School, Alfred Hospital, Melbourne, Australia
| | - Menno C van Zelm
- Allergy and Clinical Immunology Laboratory, Department of Immunology, Central Clinical School, Monash University, Melbourne, Australia; Jeffrey Modell Diagnostic and Research Centre for Primary Immunodeficiencies, Melbourne, Australia; Department of Allergy, Immunology and Respiratory Medicine, Central Clinical School, Alfred Hospital, Melbourne, Australia.
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3
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Koretzky GA. Building on the Past, Meeting the Moment. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:849-854. [PMID: 36947823 DOI: 10.4049/jimmunol.2390003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Affiliation(s)
- Gary A Koretzky
- Department of Internal Medicine, Weill Cornell Medicine, New York, NY
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca NY
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4
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Dinur-Schejter Y, Zaidman I, Mor-Shaked H, Stepensky P. The Clinical Aspect of Adaptor Molecules in T Cell Signaling: Lessons Learnt From Inborn Errors of Immunity. Front Immunol 2021; 12:701704. [PMID: 34456914 PMCID: PMC8397411 DOI: 10.3389/fimmu.2021.701704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 07/26/2021] [Indexed: 12/22/2022] Open
Abstract
Adaptor molecules lack enzymatic and transcriptional activities. Instead, they exert their function by linking multiple proteins into intricate complexes, allowing for transmitting and fine-tuning of signals. Many adaptor molecules play a crucial role in T-cell signaling, following engagement of the T-cell receptor (TCR). In this review, we focus on Linker of Activation of T cells (LAT) and SH2 domain-containing leukocyte protein of 76 KDa (SLP-76). Monogenic defects in these adaptor proteins, with known roles in T-cell signaling, have been described as the cause of human inborn errors of immunity (IEI). We describe the current knowledge based on defects in cell lines, murine models and human patients. Germline mutations in Adhesion and degranulation adaptor protein (ADAP), have not resulted in a T-cell defect.
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Affiliation(s)
- Yael Dinur-Schejter
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,The Bone Marrow Transplantation and Cancer Immunotherapy Department, Hadassah Ein Kerem Medical Center, Jerusalem, Israel.,Allergy and Clinical Immunology Unit, Hadassah Ein-Kerem Medical Center, Jerusalem, Israel
| | - Irina Zaidman
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,The Bone Marrow Transplantation and Cancer Immunotherapy Department, Hadassah Ein Kerem Medical Center, Jerusalem, Israel
| | - Hagar Mor-Shaked
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,Monique and Jacques Roboh Department of Genetic Research, Hadassah Ein Kerem Medical Center, Jerusalem, Israel
| | - Polina Stepensky
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,The Bone Marrow Transplantation and Cancer Immunotherapy Department, Hadassah Ein Kerem Medical Center, Jerusalem, Israel
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5
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Zhang Y, Wu X, Zhang W, Gao J, Zhang Y, Zhang X. Platelet indices and varicocele: A systematic review and meta-analysis. Andrologia 2020; 53:e13939. [PMID: 33369777 DOI: 10.1111/and.13939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/17/2020] [Accepted: 11/25/2020] [Indexed: 01/11/2023] Open
Abstract
The updated systematic review and meta-analysis was conducted to assess the platelet indices between patients with varicocele and healthy subject. The main purpose of our study was to explore the relationship between platelet and the pathogenesis of varicocele. Databases including Cochrane Library, PubMed, and MEDLINE were retrieved to identify studies. Two independent investigators extracted the related information of the included original passages. In order to estimate the difference of varicocele patients and healthy subjects, we applied the standardised mean difference (SMD) and the corresponding 95% confidence intervals (95% CIs). 1,156 patients and 797 healthy subjects of nine studies met the pre-set inclusion criteria. The estimated SMD in MPV between varicocele patients and healthy subjects was 0.61 (95% CI: 0.29-0.93, p < 0.001). The estimated SMD in MPV between preoperative varicocele patients and post-operative varicocele patients was 0.22 (95% CI: 0.03-0.41, p = 0.02). The estimated SMD in PLT between varicocele patients and healthy subjects was -0.19 (95% CI: -0.28, -0.08, p = 0.001). The available data suggest that a higher MPV level in varicocele patients, and the varicocele operation can normalise the preoperatively elevated mean platelet volume levels. Further researches are needed to investigate the potential role of platelet with varicocele.
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Affiliation(s)
- Yuyang Zhang
- The Department of Urology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xu Wu
- The Department of Urology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Wei Zhang
- The Department of Urology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Jingjing Gao
- The Department of Urology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yao Zhang
- The Department of Urology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Xiansheng Zhang
- The Department of Urology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
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6
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Lev A, Lee YN, Sun G, Hallumi E, Simon AJ, Zrihen KS, Levy S, Beit Halevi T, Papazian M, Shwartz N, Somekh I, Levy-Mendelovich S, Wolach B, Gavrieli R, Vernitsky H, Barel O, Javasky E, Stauber T, Ma CA, Zhang Y, Amariglio N, Rechavi G, Hendel A, Yablonski D, Milner JD, Somech R. Inherited SLP76 deficiency in humans causes severe combined immunodeficiency, neutrophil and platelet defects. J Exp Med 2020; 218:211562. [PMID: 33231617 PMCID: PMC7690938 DOI: 10.1084/jem.20201062] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 09/06/2020] [Accepted: 10/08/2020] [Indexed: 12/30/2022] Open
Abstract
The T cell receptor (TCR) signaling pathway is an ensemble of numerous proteins that are crucial for an adequate immune response. Disruption of any protein involved in this pathway leads to severe immunodeficiency and unfavorable clinical outcomes. Here, we describe an infant with severe immunodeficiency who was found to have novel biallelic mutations in SLP76. SLP76 is a key protein involved in TCR signaling and in other hematopoietic pathways. Previous studies of this protein were performed using Jurkat-derived human leukemic T cell lines and SLP76-deficient mice. Our current study links this gene, for the first time, to a human immunodeficiency characterized by early-onset life-threatening infections, combined T and B cell immunodeficiency, severe neutrophil defects, and impaired platelet aggregation. Hereby, we characterized aspects of the patient's immune phenotype, modeled them with an SLP76-deficient Jurkat-derived T cell line, and rescued some consequences using ectopic expression of wild-type SLP76. Understanding human diseases due to SLP76 deficiency is helpful in explaining the mixed T cell and neutrophil defects, providing a guide for exploring human SLP76 biology.
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Affiliation(s)
- Atar Lev
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel.,The Mina and Everard Goodman Faculty of Life Sciences, Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat Gan, Israel
| | - Yu Nee Lee
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Guangping Sun
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Enas Hallumi
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Amos J Simon
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel.,Division of Haematology and Bone Marrow Transplantation, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Keren S Zrihen
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Shiran Levy
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Tal Beit Halevi
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Maria Papazian
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Neta Shwartz
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Ido Somekh
- Department of Pediatric Hematology Oncology, Schneider Children's Medical Center of Israel, Petah Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sarina Levy-Mendelovich
- The Israeli National Hemophilia Center and Thrombosis Unit, The Amalia Biron Research Institute of Thrombosis and Hemostasis, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Baruch Wolach
- Department of Pediatrics and Laboratory for Leukocyte Function, Meir Medical Center, Kfar Saba, Israel
| | - Ronit Gavrieli
- Department of Pediatrics and Laboratory for Leukocyte Function, Meir Medical Center, Kfar Saba, Israel
| | - Helly Vernitsky
- Division of Haematology and Bone Marrow Transplantation, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ortal Barel
- The Genomic Unit, Sheba Cancer Research Center, Sheba Medical Center, Tel Hashomer, Israel.,Cancer Research Center, Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Israel
| | - Elisheva Javasky
- The Genomic Unit, Sheba Cancer Research Center, Sheba Medical Center, Tel Hashomer, Israel.,Cancer Research Center, Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Israel
| | - Tali Stauber
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Chi A Ma
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Yuan Zhang
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD.,Department of Pediatrics, Columbia University Irving Medical Center, New York, NY
| | - Ninette Amariglio
- The Mina and Everard Goodman Faculty of Life Sciences, Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat Gan, Israel.,Cancer Research Center, Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
| | - Gideon Rechavi
- Cancer Research Center, Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ayal Hendel
- The Mina and Everard Goodman Faculty of Life Sciences, Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat Gan, Israel
| | - Deborah Yablonski
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Joshua D Milner
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD.,Department of Pediatrics, Columbia University Irving Medical Center, New York, NY
| | - Raz Somech
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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7
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Borowicz P, Chan H, Hauge A, Spurkland A. Adaptor proteins: Flexible and dynamic modulators of immune cell signalling. Scand J Immunol 2020; 92:e12951. [DOI: 10.1111/sji.12951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/22/2020] [Accepted: 07/26/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Paweł Borowicz
- Department of Molecular Medicine Institute of Basic Medical Sciences University of Oslo Oslo Norway
| | - Hanna Chan
- Department of Molecular Medicine Institute of Basic Medical Sciences University of Oslo Oslo Norway
| | - Anette Hauge
- Department of Molecular Medicine Institute of Basic Medical Sciences University of Oslo Oslo Norway
| | - Anne Spurkland
- Department of Molecular Medicine Institute of Basic Medical Sciences University of Oslo Oslo Norway
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8
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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: 179] [Impact Index Per Article: 35.8] [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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9
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Rayes J, Watson SP, Nieswandt B. Functional significance of the platelet immune receptors GPVI and CLEC-2. J Clin Invest 2019; 129:12-23. [PMID: 30601137 DOI: 10.1172/jci122955] [Citation(s) in RCA: 192] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although platelets are best known for their role in hemostasis, they are also crucial in development, host defense, inflammation, and tissue repair. Many of these roles are regulated by the immune-like receptors glycoprotein VI (GPVI) and C-type lectin receptor 2 (CLEC-2), which signal through an immunoreceptor tyrosine-based activation motif (ITAM). GPVI is activated by collagen in the subendothelial matrix, by fibrin and fibrinogen in the thrombus, and by a remarkable number of other ligands. CLEC-2 is activated by the transmembrane protein podoplanin, which is found outside of the vasculature and is upregulated in development, inflammation, and cancer, but there is also evidence for additional ligands. In this Review, we discuss the physiological and pathological roles of CLEC-2 and GPVI and their potential as targets in thrombosis and thrombo-inflammatory disorders (i.e., disorders in which inflammation plays a critical role in the ensuing thrombosis) relative to current antiplatelet drugs.
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Affiliation(s)
- Julie Rayes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Steve P Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, United Kingdom
| | - Bernhard Nieswandt
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
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10
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Rodgers TD, Reagan PM. Targeting the B-cell receptor pathway: a review of current and future therapies for non-Hodgkin's lymphoma. Expert Opin Emerg Drugs 2018; 23:111-122. [PMID: 29781323 DOI: 10.1080/14728214.2018.1479396] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
INTRODUCTION The B-cell receptor (BCR) pathway is a crucial aspect of mature lymphocytes and is maintained in B-cell neoplasms. Many small module inhibitors targeting kinases within the BCR pathway are approved, with others in development, offering alternative treatment options to standard chemoimmunotherapy. Areas covered: This review covers both approved inhibitors and investigational inhibitors of spleen tyrosine kinase (SYK), Bruton's tyrosine kinase (BTK), and phosphoinositide-3-kinase (PI3K) in the treatment of B-cell lymphomas. To collect relevant articles, a literature search was completed through the use of PubMed and abstracts from ASH and ASCO national meetings. Search terms including non-Hodgkin lymphoma, and BCR inhibitors, as well as the individual drug names, were utilized. The majority of included studies are dated from 2012 to March 2018. Expert opinion: BCR pathway inhibitors, such as ibrutinib and idelalisib, are novel treatments for non-Hodgkin lymphomas. While providing alternative treatment options to those with high-risk disease, poor functional status, and relapsed disease, outside of chronic lymphocytic leukemia (CLL), they have been limited to the relapsed/refractory setting. Their mechanisms of action, off/on-target effects, and resistance patterns create unique therapeutic dilemmas. It is our opinion that more specific inhibitors, as well as combination therapy, will define the future for BCR inhibitors.
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Affiliation(s)
- Thomas D Rodgers
- a James P. Wilmot Cancer Institute, University of Rochester Medical Center , Rochester , NY.,b Department of Medicine , Division of Hematology Oncology , United States
| | - Patrick M Reagan
- b Department of Medicine , Division of Hematology Oncology , United States
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11
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Estevez B, Du X. New Concepts and Mechanisms of Platelet Activation Signaling. Physiology (Bethesda) 2017; 32:162-177. [PMID: 28228483 DOI: 10.1152/physiol.00020.2016] [Citation(s) in RCA: 189] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Upon blood vessel injury, platelets are exposed to adhesive proteins in the vascular wall and soluble agonists, which initiate platelet activation, leading to formation of hemostatic thrombi. Pathological activation of platelets can induce occlusive thrombosis, resulting in ischemic events such as heart attack and stroke, which are leading causes of death globally. Platelet activation requires intracellular signal transduction initiated by platelet receptors for adhesion proteins and soluble agonists. Whereas many platelet activation signaling pathways have been established for many years, significant recent progress reveals much more complex and sophisticated signaling and amplification networks. With the discovery of new receptor signaling pathways and regulatory networks, some of the long-standing concepts of platelet signaling have been challenged. This review provides an overview of the new developments and concepts in platelet activation signaling.
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Affiliation(s)
- Brian Estevez
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Xiaoping Du
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
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12
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Abstract
Integrin αIIbβ3 is a highly abundant heterodimeric platelet receptor that can transmit information bidirectionally across the plasma membrane, and plays a critical role in hemostasis and thrombosis. Upon platelet activation, inside-out signaling pathways increase the affinity of αIIbβ3 for fibrinogen and other ligands. Ligand binding and integrin clustering subsequently stimulate outside-in signaling, which initiates and amplifies a range of cellular events driving essential platelet processes such as spreading, thrombus consolidation, and clot retraction. Integrin αIIbβ3 has served as an excellent model for the study of integrin biology, and it has become clear that integrin outside-in signaling is highly complex and involves a vast array of enzymes, signaling adaptors, and cytoskeletal components. In this review, we provide a concise but comprehensive overview of αIIbβ3 outside-in signaling, focusing on the key players involved, and how they cooperate to orchestrate this critical aspect of platelet biology. We also discuss gaps in the current understanding of αIIbβ3 outside-in signaling and highlight avenues for future investigation.
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13
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Mokada-Gopal L, Boeser A, Lehmann CHK, Drepper F, Dudziak D, Warscheid B, Voehringer D. Identification of Novel STAT6-Regulated Proteins in Mouse B Cells by Comparative Transcriptome and Proteome Analysis. THE JOURNAL OF IMMUNOLOGY 2017; 198:3737-3745. [DOI: 10.4049/jimmunol.1601838] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 03/03/2017] [Indexed: 12/13/2022]
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14
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Zhou Y, Abraham S, Renna S, Edelstein LC, Dangelmaier CA, Tsygankov AY, Kunapuli SP, Bray PF, McKenzie SE. TULA-2 (T-Cell Ubiquitin Ligand-2) Inhibits the Platelet Fc Receptor for IgG IIA (FcγRIIA) Signaling Pathway and Heparin-Induced Thrombocytopenia in Mice. Arterioscler Thromb Vasc Biol 2016; 36:2315-2323. [PMID: 27765766 DOI: 10.1161/atvbaha.116.307979] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 10/04/2016] [Indexed: 12/19/2022]
Abstract
OBJECTIVE The objective of this study is to investigate the role of T-cell ubiquitin ligand-2 (TULA-2) in the platelet Fc receptor for IgG IIA (FcγRIIA) pathway and in the pathogenesis of heparin-induced thrombocytopenia (HIT). APPROACH AND RESULTS HIT is a life-threatening thrombotic disease in which IgG antibodies against the heparin-platelet factor 4 complex activate platelets via FcγRIIA. We reported previously differential expression of TULA-2 in human population was linked to FcγRIIA responsiveness. In this study, we investigated the role of TULA-2, a protein phosphatase, in the FcγRIIA pathway and HIT pathogenesis by crossing TULA-2-/- mice with transgenic FcγRIIA +/+ mice. Ablation of TULA-2 resulted in hyperphosphorylation of spleen tyrosine kinase, linker for the activation of T cells, and phospholipase Cγ2 in platelets via FcγRIIA activation. Platelet integrin activation, granule secretion, phosphatidylserine exposure, and aggregation were also enhanced in TULA-2-/- murine platelets. Compared with wild-type mice, TULA-2-/- mice showed aggravated antibody-mediated thrombocytopenia, augmented thrombin generation, and shortened tail bleeding time. In contrast, there was no significant difference between TULA-2-/- and TULA-2+/+ platelets in platelet spreading and clot retraction. Of note, heterozygous TULA-2+/- mice, whose platelets contained 50% as much protein as the TULA-2+/+ platelets, showed significantly increased platelet reactivity and more severe thrombocytopenia in vivo compared with TULA-2+/+ mice. CONCLUSIONS Together, the data demonstrate that not only the absence of TULA-2 but also the relative level of TULA-2 expression modulates FcγRIIA-mediated platelet reactivity and HIT in vivo. TULA-2 expression could be a valuable marker for HIT and inhibiting TULA-2 may serve as a potential therapy to reverse the bleeding adverse effect of anticoagulants.
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Affiliation(s)
- Yuhang Zhou
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Shaji Abraham
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Stephanie Renna
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Leonard C Edelstein
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Carol A Dangelmaier
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Alexander Y Tsygankov
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Satya P Kunapuli
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Paul F Bray
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.)
| | - Steven E McKenzie
- From the Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA (Y.Z., S.A., S.R., L.C.E., P.F.B., S.E.M.); and Department of Physiology, Sol Sherry Thrombosis Research Center, Temple University, Philadelphia, PA (C.A.D., A.Y.T., S.P.K.).
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Dezorella N, Katz BZ, Shapiro M, Polliack A, Perry C, Herishanu Y. SLP76 integrates into the B-cell receptor signaling cascade in chronic lymphocytic leukemia cells and is associated with an aggressive disease course. Haematologica 2016; 101:1553-1562. [PMID: 27443285 DOI: 10.3324/haematol.2015.139154] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 07/12/2016] [Indexed: 01/07/2023] Open
Abstract
I In the last decade, the B-cell receptor has emerged as a pivotal stimulus in the pathogenesis of chronic lymphocytic leukemia, and a very feasible therapeutic target in this disease. B-cell receptor responsiveness in chronic lymphocytic leukemia cells is heterogeneous among patients and correlates with aggressiveness of the disease. Here we show, for the first time, that SLP76, a key scaffold protein in T-cell receptor signaling, is ectopically expressed in chronic lymphocytic leukemia cells, with variable levels among patients, and correlates positively with unmutated immunoglobulin heavy chain variable gene status and ZAP-70 expression. We found that SLP76 was functionally active in chronic lymphocytic leukemia cells. A SYK-dependent basal level of phosphorylated SLP76 exists in the cells, and upon B-cell receptor engagement, SLP76 tyrosine phosphorylation is significantly enhanced concomitantly with increased physical association with BTK. B-cell receptor-induced SLP76 phosphorylation is mediated by upstream signaling events involving LCK and SYK. Knockdown of SLP76 in the cells resulted in decreased induction of BTK, PLCγ2 and IκB phosphorylation, as well as cell viability after B-cell receptor activation with anti-IgM. Consistent with our biochemical findings, high total SLP76 expression in chronic lymphocytic leukemia cells correlated with a more aggressive disease course. IN CONCLUSION SLP76 is ectopically expressed in chronic lymphocytic leukemia cells where it plays a role in B-cell receptor signaling.
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Affiliation(s)
- Nili Dezorella
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Jerusalem, Israel
| | - Ben-Zion Katz
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Jerusalem, Israel
| | - Mika Shapiro
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel
| | - Aaron Polliack
- Department of Hematology, Hadassah University Hospital and Hebrew University Medical School, Jerusalem, Israel
| | - Chava Perry
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel
| | - Yair Herishanu
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel .,Sackler Faculty of Medicine, Tel-Aviv University, Jerusalem, Israel
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16
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Lee RH, Bergmeier W. Platelet immunoreceptor tyrosine-based activation motif (ITAM) and hemITAM signaling and vascular integrity in inflammation and development. J Thromb Haemost 2016; 14:645-54. [PMID: 26749528 DOI: 10.1111/jth.13250] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/24/2015] [Indexed: 01/13/2023]
Abstract
Platelets are essential for maintaining hemostasis following mechanical injury to the vasculature. Besides this established function, novel roles of platelets are becoming increasingly recognized, which are critical in non-injury settings to maintain vascular barrier integrity. For example, during embryogenesis platelets act to support the proper separation of blood and lymphatic vessels. This role continues beyond birth, where platelets prevent leakage of blood into the lymphatic vessel network. During the course of inflammation, platelets are necessary to prevent local hemorrhage due to neutrophil diapedesis and disruption of endothelial cell-cell junctions. Surprisingly, platelets also work to secure tumor-associated blood vessels, inhibiting excessive vessel permeability and intra-tumor hemorrhaging. Interestingly, many of these novel platelet functions depend on immunoreceptor tyrosine-based activation motif (ITAM) signaling but not on signaling via G protein-coupled receptors, which plays a crucial role in platelet plug formation at sites of mechanical injury. Murine platelets express two ITAM-containing receptors: the Fc receptor γ-chain (FcRγ), which functionally associates with the collagen receptor GPVI, and the C-type lectin-like 2 (CLEC-2) receptor, a hemITAM receptor for the mucin-type glycoprotein podoplanin. Human platelets express an additional ITAM receptor, FcγRIIA. These receptors share common downstream effectors, including Syk, SLP-76 and PLCγ2. Here we will review the recent literature that highlights a critical role for platelet GPVI/FcRγ and CLEC-2 in vascular integrity during development and inflammation in mice and discuss the relevance to human disease.
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Affiliation(s)
- R H Lee
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | - W Bergmeier
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, USA
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17
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Podoplanin and CLEC-2 drive cerebrovascular patterning and integrity during development. Blood 2015; 125:3769-77. [PMID: 25908104 DOI: 10.1182/blood-2014-09-603803] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 04/15/2015] [Indexed: 02/06/2023] Open
Abstract
Mice with a constitutive or platelet-specific deletion of the C-type-lectin-like receptor (CLEC-2) exhibit hemorrhaging in the brain at mid-gestation. We sought to investigate the basis of this defect, hypothesizing that it is mediated by the loss of CLEC-2 activation by its endogenous ligand, podoplanin, which is expressed on the developing neural tube. To induce deletion of podoplanin at the 2-cell stage, we generated a podoplanin(fl/fl) mouse crossed to a PGK-Cre mouse. Using 3-dimensional light-sheet microscopy, we observed cerebral vessels were tortuous and aberrantly patterned at embryonic (E) day 10.5 in podoplanin- and CLEC-2-deficient mice, preceding the formation of large hemorrhages throughout the fore-, mid-, and hindbrain by E11.5. Immunofluorescence and electron microscopy revealed defective pericyte recruitment and misconnections between the endothelium of developing blood vessels and surrounding pericytes and neuro-epithelial cells. Nestin-Cre-driven deletion of podoplanin on neural progenitors also caused widespread cerebral hemorrhaging. Hemorrhaging was also seen in the ventricles of embryos deficient in the platelet integrin subunit glycoprotein IIb or in embryos in which platelet α-granule and dense granule secretion is abolished. We propose a novel role for podoplanin on the neuro-epithelium, which interacts with CLEC-2 on platelets, mediating platelet adhesion, aggregation, and secretion to guide the maturation and integrity of the developing vasculature and prevent hemorrhage.
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18
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Marjoram RJ, Li Z, He L, Tollefsen DM, Kunicki TJ, Dickeson SK, Santoro SA, Zutter MM. α2β1 integrin, GPVI receptor, and common FcRγ chain on mouse platelets mediate distinct responses to collagen in models of thrombosis. PLoS One 2014; 9:e114035. [PMID: 25415203 PMCID: PMC4240667 DOI: 10.1371/journal.pone.0114035] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 11/03/2014] [Indexed: 12/29/2022] Open
Abstract
Objective Platelets express the α2β1 integrin and the glycoprotein VI (GPVI)/FcRγ complex, both collagen receptors. Understanding platelet-collagen receptor function has been enhanced through use of genetically modified mouse models. Previous studies of GPVI/FcRγ-mediated collagen-induced platelet activation were perfomed with mice in which the FcRγ subunit was genetically deleted (FcRγ−/−) or the complex was depleted. The development of α2β1−/− and GPVI−/− mice permits side-by-side comparison to address contributions of these collagen receptors in vivo and in vitro. Approach and Results To understand the different roles played by the α2β1 integrin, the GPVI receptor or FcRγ subunit in collagen-stimulated hemostasis and thrombosis, we compared α2β1−/−, FcRγ−/−, and GPVI−/− mice in models of endothelial injury and intravascular thrombosis in vivo and their platelets in collagen-stimulated activation in vitro. We demonstrate that both the α2β1 integrin and the GPVI receptor, but not the FcRγ subunit influence carotid artery occlusion in vivo. In contrast, the GPVI receptor and the FcRγ chain, but not the α2β1 integrin, play similar roles in intravascular thrombosis in response to soluble Type I collagen. FcRγ−/− platelets showed less attenuation of tyrosine phosphorylation of several proteins including RhoGDI when compared to GPVI−/− and wild type platelets. The difference between FcRγ−/− and GPVI−/− platelet phosphotyrosine levels correlated with the in vivo thrombosis findings. Conclusion Our data demonstrate that genetic deletion of GPVI receptor, FcRγ chain, or the α2β1 integrin changes the thrombotic potentials of these platelets to collagen dependent on the stimulus mechanism. The data suggest that the FcRγ chain may provide a dominant negative effect through modulating signaling pathways in platelets involving several tyrosine phosphorylated proteins such as RhoGDI. In addition, these findings suggest a more complex signaling network downstream of the platelet collagen receptors than previously appreciated.
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Affiliation(s)
- Robin J. Marjoram
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Zhengzhi Li
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Li He
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Douglas M. Tollefsen
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Thomas J. Kunicki
- Children's Hospital of Orange County, Orange, CA, United States of America
| | - S. Kent Dickeson
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Samuel A. Santoro
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Mary M. Zutter
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- * E-mail:
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The N-terminal SH2 domain of Syk is required for (hem)ITAM, but not integrin, signaling in mouse platelets. Blood 2014; 125:144-54. [PMID: 25352128 DOI: 10.1182/blood-2014-05-579375] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have used a novel knockin mouse to investigate the effect of disruption of phosphotyrosine binding of the N-terminal SH2 domain of Syk on platelet activation by GPVI, CLEC-2, and integrin αIIbβ3. The Syk(R41Afl/fl) mouse was crossed to a PF4-Cre(+) mouse to induce expression of the Syk mutant in the megakaryocyte/platelet lineage. Syk(R41Afl/fl;PF4-Cre) mice are born at approximately 50% of the expected frequency and have a similar phenotype to Syk(fl/fl;PF4-Cre) mice, including blood-lymphatic mixing and chyloascites. Anastomosis of the venous and lymphatic vasculatures can be seen in the mesenteric circulation accounting for rapid and continuous mixing of the 2 vasculatures. Platelet activation by CLEC-2 and GPVI is abolished in Syk(R41Afl/fl;PF4-Cre) platelets. Syk phosphorylation on Tyr519/20 is blocked in CLEC-2-stimulated platelets, suggesting a model in which binding of Syk via its N-terminal SH2 domain regulates autophosphorylation. In contrast, outside-in signaling by integrin αIIbβ3 is not altered, but it is inhibited in the presence of inhibitors of Src and Syk tyrosine kinases. These results demonstrate that αIIbβ3 regulates Syk through an ITAM-independent pathway in mice and provide novel insight into the course of events underlying Syk activation and hemITAM phosphorylation by CLEC-2.
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20
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Boulaftali Y, Hess PR, Kahn ML, Bergmeier W. Platelet immunoreceptor tyrosine-based activation motif (ITAM) signaling and vascular integrity. Circ Res 2014; 114:1174-84. [PMID: 24677237 PMCID: PMC4000726 DOI: 10.1161/circresaha.114.301611] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 02/18/2014] [Indexed: 01/27/2023]
Abstract
Platelets are well-known for their critical role in hemostasis, that is, the prevention of blood loss at sites of mechanical vessel injury. Inappropriate platelet activation and adhesion, however, can lead to thrombotic complications, such as myocardial infarction and stroke. To fulfill its role in hemostasis, the platelet is equipped with various G protein-coupled receptors that mediate the response to soluble agonists such as thrombin, ADP, and thromboxane A2. In addition to G protein-coupled receptors, platelets express 3 glycoproteins that belong to the family of immunoreceptor tyrosine-based activation motif receptors: Fc receptor γ chain, which is noncovalently associated with the glycoprotein VI collagen receptor, C-type lectin 2, the receptor for podoplanin, and Fc receptor γII A, a low-affinity receptor for immune complexes. Although both genetic and chemical approaches have documented a critical role for platelet G protein-coupled receptors in hemostasis, the contribution of immunoreceptor tyrosine-based activation motif receptors to this process is less defined. Studies performed during the past decade, however, have identified new roles for platelet immunoreceptor tyrosine-based activation motif signaling in vascular integrity in utero and at sites of inflammation. The purpose of this review is to summarize recent findings on how platelet immunoreceptor tyrosine-based activation motif signaling controls vascular integrity, both in the presence and absence of mechanical injury.
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Affiliation(s)
- Yacine Boulaftali
- From the McAllister Heart Institute (Y.B., W.B.) and Department of Biochemistry and Biophysics (W.B.), University of North Carolina, Chapel Hill; and Department of Medicine and Division of Cardiology, University of Pennsylvania, Philadelphia (P.R.H., M.L.K.)
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21
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Overview of platelet physiology: its hemostatic and nonhemostatic role in disease pathogenesis. ScientificWorldJournal 2014; 2014:781857. [PMID: 24729754 PMCID: PMC3960550 DOI: 10.1155/2014/781857] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 11/10/2013] [Indexed: 12/23/2022] Open
Abstract
Platelets are small anucleate cell fragments that circulate in blood playing crucial role in managing vascular integrity and regulating hemostasis. Platelets are also involved in the fundamental biological process of chronic inflammation associated with disease pathology. Platelet indices like mean platelets volume (MPV), platelets distributed width (PDW), and platelet crit (PCT) are useful as cheap noninvasive biomarkers for assessing the diseased states. Dynamic platelets bear distinct morphology, where α and dense granule are actively involved in secretion of molecules like GPIIb , IIIa, fibrinogen, vWf, catecholamines, serotonin, calcium, ATP, ADP, and so forth, which are involved in aggregation. Differential expressions of surface receptors like CD36, CD41, CD61 and so forth have also been quantitated in several diseases. Platelet clinical research faces challenges due to the vulnerable nature of platelet structure functions and lack of accurate assay techniques. But recent advancement in flow cytometry inputs huge progress in the field of platelets study. Platelets activation and dysfunction have been implicated in diabetes, renal diseases, tumorigenesis, Alzheimer's, and CVD. In conclusion, this paper elucidates that platelets are not that innocent as they keep showing and thus numerous novel platelet biomarkers are upcoming very soon in the field of clinical research which can be important for predicting and diagnosing disease state.
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22
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Lowe KL, Navarro-Nunez L, Watson SP. Platelet CLEC-2 and podoplanin in cancer metastasis. Thromb Res 2012; 129 Suppl 1:S30-7. [PMID: 22682130 DOI: 10.1016/s0049-3848(12)70013-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It has long been recognised that the function of platelets in health and disease span far beyond their roles in haemostasis and thrombosis. The observation that tumour cells induce platelet aggregation was followed by extensive experimental evidence linking platelets to cancer progression. Aggregated platelets coat tumour cells during their transit through the bloodstream and mediate adherence to vascular endothelium, protection from shear stresses, evasion from immune molecules, and release of an array of bioactive molecules that facilitate tumour cell extravasation and growth at metastatic sites. The sialyated membrane glycoprotein podoplanin is found on the leading edge of tumour cells and is thought to influence their migratory and invasive properties. Podoplanin elicits powerful platelet aggregation and is the endogenous ligand for the platelet C-type lectin receptor, CLEC-2, which itself regulates podoplanin signalling. Here, the bidirectional relationship between CLEC-2 and podoplanin is described and considered in the context of tumour growth and metastasis.
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Affiliation(s)
- Kate L Lowe
- Centre for Cardiovascular Sciences, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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23
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Chen CY, Bertozzi C, Zou Z, Yuan L, Lee JS, Lu M, Stachelek SJ, Srinivasan S, Guo L, Vicente A, Vincente A, Mericko P, Levy RJ, Makinen T, Oliver G, Kahn ML. Blood flow reprograms lymphatic vessels to blood vessels. J Clin Invest 2012; 122:2006-17. [PMID: 22622036 DOI: 10.1172/jci57513] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 04/05/2012] [Indexed: 01/30/2023] Open
Abstract
Human vascular malformations cause disease as a result of changes in blood flow and vascular hemodynamic forces. Although the genetic mutations that underlie the formation of many human vascular malformations are known, the extent to which abnormal blood flow can subsequently influence the vascular genetic program and natural history is not. Loss of the SH2 domain-containing leukocyte protein of 76 kDa (SLP76) resulted in a vascular malformation that directed blood flow through mesenteric lymphatic vessels after birth in mice. Mesenteric vessels in the position of the congenital lymphatic in mature Slp76-null mice lacked lymphatic identity and expressed a marker of blood vessel identity. Genetic lineage tracing demonstrated that this change in vessel identity was the result of lymphatic endothelial cell reprogramming rather than replacement by blood endothelial cells. Exposure of lymphatic vessels to blood in the absence of significant flow did not alter vessel identity in vivo, but lymphatic endothelial cells exposed to similar levels of shear stress ex vivo rapidly lost expression of PROX1, a lymphatic fate-specifying transcription factor. These findings reveal that blood flow can convert lymphatic vessels to blood vessels, demonstrating that hemodynamic forces may reprogram endothelial and vessel identity in cardiovascular diseases associated with abnormal flow.
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Affiliation(s)
- Chiu-Yu Chen
- Department of Medicine and Division of Cardiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Block H, Herter JM, Rossaint J, Stadtmann A, Kliche S, Lowell CA, Zarbock A. Crucial role of SLP-76 and ADAP for neutrophil recruitment in mouse kidney ischemia-reperfusion injury. ACTA ACUST UNITED AC 2012; 209:407-21. [PMID: 22291096 PMCID: PMC3280874 DOI: 10.1084/jem.20111493] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Leukocyte recruitment to the kidney during acute injury is mediated by E-selectin–mediated rolling and requires SLP-76 and the adaptor protein ADAP. Neutrophils trigger inflammation-induced acute kidney injury (AKI), a frequent and potentially lethal occurrence in humans. Molecular mechanisms underlying neutrophil recruitment to sites of inflammation have proved elusive. In this study, we demonstrate that SLP-76 (SH2 domain–containing leukocyte phosphoprotein of 76 kD) and ADAP (adhesion and degranulation promoting adaptor protein) are involved in E-selectin–mediated integrin activation and slow leukocyte rolling, which promotes ischemia-reperfusion–induced AKI in mice. By using genetically engineered mice and transduced Slp76−/− primary leukocytes, we demonstrate that ADAP as well as two N-terminal–located tyrosines and the SH2 domain of SLP-76 are required for downstream signaling and slow leukocyte rolling. The Tec family kinase Bruton tyrosine kinase is downstream of SLP-76 and, together with ADAP, regulates PI3Kγ (phosphoinositide 3-kinase–γ)- and PLCγ2 (phospholipase Cγ2)-dependent pathways. Blocking both pathways completely abolishes integrin affinity and avidity regulation. Thus, SLP-76 and ADAP are involved in E-selectin–mediated integrin activation and neutrophil recruitment to inflamed kidneys, which may underlie the development of life-threatening ischemia-reperfusion–induced AKI in humans.
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Affiliation(s)
- Helena Block
- Department of Anesthesiology and Critical Care Medicine, University of Münster, 48149 Münster, Germany
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25
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Abstract
Three classes of inhibitors of platelet aggregation have demonstrated substantial clinical benfits. Aspirin acts by irreversibly inhibiting COX-1 and therefore blocking the synthesis of proaggregatory thromboxane A (2) (TxA(2)). The indirect acting (ticlopidine, clopidogrel, prasugrel) and the direct acting (ticagrelor) antagonists of P2Y(12) block the thrombus stabilizing activity of ADP. Parenteral GP IIb-IIIa inhibitors directly block platelet-platelet interactions. Despite well-established benefits, all antiplatelet agents have important limitations: increased bleeding and gastrointestinal toxicities (aspirin), high incidence of thrombotic thrombocytopenic purpura (ticlopidine), potentially nonresponders (clopidogrel), severe bleeding (prasugrel, GP IIb-IIIa antagonists) and "complicated" relationships with aspirin ticagrelor). In this chapter, we present the genetic and pharmacological evidence that supports the development and expectations associated with novel antiplatelet strategies directed at intrasignaling pathways.
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Affiliation(s)
- Patrick Andre
- Portola Pharmaceuticals Inc, 270 E. Grand Avenue, Suite 22 South, San Francisco, CA 94080, USA.
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26
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Wondimu A, Weir L, Robertson D, Mezentsev A, Kalachikov S, Panteleyev AA. Loss of Arnt (Hif1β) in mouse epidermis triggers dermal angiogenesis, blood vessel dilation and clotting defects. J Transl Med 2012; 92:110-24. [PMID: 21946855 DOI: 10.1038/labinvest.2011.134] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Targeted ablation of Aryl hydrocarbon receptor nuclear translocator (Arnt) in the mouse epidermis results in severe abnormalities in dermal vasculature reminiscent of petechia induced in human skin by anticoagulants or certain genetic disorders. Lack of Arnt leads to downregulation of Egln3/Phd3 hydroxylase and concomitant hypoxia-independent stabilization of hypoxia-induced factor 1α (Hif1α) along with compensatory induction of Arnt2. Ectopic induction of Arnt2 results in its heterodimerization with stabilized Hif1α and is associated with activation of genes coding for secreted proteins implicated in control of angiogenesis, coagulation, vasodilation and blood vessel permeability such as S100a8/S100a9, S100a10, Serpine1, Defb3, Socs3, Cxcl1 and Thbd. Since ARNT and ARNT2 heterodimers with HIF1α are known to have different (yet overlapping) downstream targets our findings suggest that loss of Arnt in the epidermis activates an aberrant paracrine regulatory pathway responsible for dermal vascular phenotype in K14-Arnt KO mice. This assumption is supported by a significant decline of von Willebrand factor in dermal vasculature of these mice where Arnt level remains normal. Given the essential role of ARNT in the adaptive response to environmental stress and striking similarity between skin vascular phenotype in K14-Arnt KO mice and specific vascular features of tumour stroma and psoriatic skin, we believe that further characterization of Arnt-dependent epidermal-dermal signalling may provide insight into the role of macro- and micro-environmental factors in control of skin vasculature and in pathogenesis of environmentally modulated skin disorders.
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Affiliation(s)
- Assefa Wondimu
- Department of Dermatology, Columbia University, New York, NY, USA
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27
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Takiguchi M, James C, Josefsson EC, Carmichael CL, Premsrirut PK, Lowe SW, Hamilton JR, Huang DCS, Kile BT, Dickins RA. Transgenic, inducible RNAi in megakaryocytes and platelets in mice. J Thromb Haemost 2010; 8:2751-6. [PMID: 21138522 PMCID: PMC3285240 DOI: 10.1111/j.1538-7836.2010.04077.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND RNA interference (RNAi) is a powerful tool for suppressing gene function. The tetracycline (tet)-regulated expression system has recently been adapted to allow inducible RNAi in mice, however its efficiency in a particular cell type in vivo depends on a transgenic tet transactivator expression pattern and is often highly variable. OBJECTIVE We aimed to establish a transgenic strategy that allows efficient and inducible gene knockdown in particular hematopoietic lineages in mice. METHODS AND RESULTS Using a tet-regulated reporter gene strategy, we found that transgenic mice expressing the rtTA (tet-on) transactivator under control of the cytomegalovirus (CMV) promoter (CMV-rtTA mice) display inducible reporter gene expression with unusual and near-complete efficiency in megakaryocytes and platelets. To test whether the CMV-rtTA transgene can drive inducible and efficient gene knockdown within this lineage, we generated a novel mouse strain harboring a tet-regulated short hairpin RNA (shRNA) targeting Bcl-x(L) , a pro-survival Bcl-2 family member known to be essential for maintaining platelet survival. Doxycycline treatment of adult mice carrying both transgenes induces shRNA expression, depletes Bcl-x(L) in megakaryocytes and triggers severe thrombocytopenia, whereas doxycycline withdrawal shuts off shRNA expression, normalizes Bcl-x(L) levels and restores platelet numbers. These effects are akin to those observed with drugs that target Bcl-x(L) , clearly demonstrating that this transgenic system allows efficient and inducible inhibition of genes in megakaryocytes and platelets. CONCLUSIONS We have established a novel transgenic strategy for inducible gene knockdown in megakaryocytes and platelets that will be useful for characterizing genes involved in platelet production and function in adult mice.
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Affiliation(s)
- M Takiguchi
- Molecular Medicine Division Chemical Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
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28
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Understanding signal integration through targeted mutations of an adapter protein. FEBS Lett 2010; 584:4901-9. [PMID: 20965179 DOI: 10.1016/j.febslet.2010.10.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 10/13/2010] [Indexed: 11/23/2022]
Abstract
Immunoreceptor engagement leads to the activation of multiple second messenger cascades, and integration of these pathways requires proper function of a number of adapter proteins. Although adapters possess no intrinsic enzymatic function, they nucleate the formation of multi-molecular protein complexes to support downstream signaling. Since adapters contain functionally distinct domains, intense investigation has been devoted to understanding how these regions act to integrate signals. This review describes the evolution of studies investigating one of these adapters, the SH2 domain-containing leukocyte protein of 76 kDa. Through utilizing biochemical, genetic and imaging techniques, a model has emerged describing how this adapter regulates signals resulting in complex immune responses.
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29
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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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30
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Mócsai A, Ruland J, Tybulewicz VLJ. The SYK tyrosine kinase: a crucial player in diverse biological functions. Nat Rev Immunol 2010; 10:387-402. [PMID: 20467426 PMCID: PMC4782221 DOI: 10.1038/nri2765] [Citation(s) in RCA: 925] [Impact Index Per Article: 66.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Spleen tyrosine kinase (SYK) is known to have a crucial role in adaptive immune receptor signalling. However, recent reports indicate that SYK also mediates other, unexpectedly diverse biological functions, including cellular adhesion, innate immune recognition, osteoclast maturation, platelet activation and vascular development. SYK is activated by C-type lectins and integrins, and activates new targets, including the CARD9-BCL-10-MALT1 pathway and the NLRP3 inflammasome. Studies using Drosophila melanogaster suggest that there is an evolutionarily ancient origin of SYK-mediated signalling. Moreover, SYK has a crucial role in autoimmune diseases and haematological malignancies. This Review summarizes our current understanding of the diverse functions of SYK and how this is being translated for therapeutic purposes.
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Affiliation(s)
- Attila Mócsai
- Department of Physiology, Semmelweis University School of Medicine, 1094 Budapest, Hungary.
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31
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Jordan MS, Koretzky GA. Coordination of receptor signaling in multiple hematopoietic cell lineages by the adaptor protein SLP-76. Cold Spring Harb Perspect Biol 2010; 2:a002501. [PMID: 20452948 DOI: 10.1101/cshperspect.a002501] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The adaptor protein SLP-76 is expressed in multiple hematopoietic lineages including T cells, platelets, and neutrophils. SLP-76 mediated signaling is dependent on its multiple protein interaction domains, as it creates a scaffold on which key signaling complexes are built. SLP-76 is critical for supporting signaling downstream of both immunoreceptors and integrins. The signaling molecules used both upstream and downstream of SLP-76 are similar among these receptors and across cell types; however, important differences exist. Appreciating how SLP-76 coordinates signal transduction across different cell and receptor types provides insights into the complex interplay of pathways critical for activation of cells of the immune system that are essential for host defense.
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Affiliation(s)
- Martha S Jordan
- Abramson Family Cancer Institute, University of Pennsylvania, Philadelphia, 19104, USA
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32
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Novel function for blood platelets and podoplanin in developmental separation of blood and lymphatic circulation. Blood 2010; 115:3997-4005. [PMID: 20110424 DOI: 10.1182/blood-2009-04-216069] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
During embryonic development, lymph sacs form from the cardinal vein, and sprout centrifugally to form mature lymphatic networks. Separation of the lymphatic from the blood circulation by a hitherto unknown mechanism is essential for the homeostatic function of the lymphatic system. O-glycans on the lymphatic endothelium have recently been suggested to be required for establishment and maintenance of distinct blood and lymphatic systems, primarily by mediating proper function of podoplanin. Here, we show that this separation process critically involves platelet activation by podoplanin. We found that platelet aggregates build up in wild-type embryos at the separation zone of podoplanin(+) lymph sacs and cardinal veins, but not in podoplanin(-/-) embryos. Thus, podoplanin(-/-) mice develop a "nonseparation" phenotype, characterized by a blood-filled lymphatic network after approximately embryonic day 13.5, which, however, partially resolves in postnatal mice. The same embryonic phenotype is also induced by treatment of pregnant mice with acetyl salicylic acid, podoplanin-blocking antibodies, or by inactivation of the kindlin-3 gene required for platelet aggregation. Therefore, interaction of endothelial podoplanin of the developing lymph sac with circulating platelets from the cardinal vein is critical for separating the lymphatic from the blood vascular system.
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33
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Jackson SP, Schoenwaelder SM. PI 3-Kinase p110β regulation of platelet integrin α(IIb)β3. Curr Top Microbiol Immunol 2010; 346:203-24. [PMID: 20517720 DOI: 10.1007/82_2010_61] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hemopoietic cells express relatively high levels of the type I phosphoinositide (PI) 3-kinase isoforms, with p110δ and γ exhibiting specialized signaling functions in neutrophils, monocytes, mast cells, and lymphocytes. In platelets, p110β appears to be the dominant PI 3-kinase isoform regulating platelet activation, irrespective of the nature of the primary platelet activating stimulus. Based on findings with isoform-selective p110β pharmacological inhibitors and more recently with p110β-deficient platelets, p110β appears to primarily signal downstream of G(i)- and tyrosine kinase-coupled receptors. Functionally, inhibition of p110β kinase function leads to a marked defect in integrin α(IIb)β₃ adhesion and reduced platelet thrombus formation in vivo. This defect in platelet adhesive function is not associated with increased bleeding, suggesting that therapeutic targeting of p110β may represent a safe approach to reduce thrombotic complications in patients with cardiovascular disease.
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Affiliation(s)
- Shaun P Jackson
- Australian Centre for Blood Diseases, Alfred Medical Research and Education Precinct (AMREP), Monash University, Melbourne, VIC, 3004, Australia.
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34
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O’Callaghan CA. Thrombomodulation via CLEC-2 targeting. Curr Opin Pharmacol 2009; 9:90-5. [DOI: 10.1016/j.coph.2008.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 11/03/2008] [Indexed: 12/22/2022]
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35
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Hughes CE, Auger JM, McGlade J, Eble JA, Pearce AC, Watson SP. Differential roles for the adapters Gads and LAT in platelet activation by GPVI and CLEC-2. J Thromb Haemost 2008; 6:2152-9. [PMID: 18826392 PMCID: PMC2710801 DOI: 10.1111/j.1538-7836.2008.03166.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 08/25/2008] [Indexed: 11/27/2022]
Abstract
BACKGROUND The adapter proteins SLP-76 and LAT have been shown to play critical roles in the activation of PLCgamma2 in platelets downstream of GPVI/FcRgamma and the C-type lectin receptor CLEC-2. SLP-76 is constitutively associated with the adapter Gads in platelets, which also binds to tyrosine phosphorylated LAT, thereby providing a potential pathway of regulation of SLP-76. OBJECTIVE In the present study, we have compared the role of Gads alongside that of LAT following activation of the major platelet glycoprotein receptors using mice deficient in the two adapter proteins. RESULTS Gads was found to be required for the efficient onset of aggregation and secretion in response to submaximal stimulation of GPVI and CLEC-2, but to be dispensable for activation following stronger stimulation of the two receptors. Gads was also dispensable for spreading induced through integrin alpha(IIb)beta(3) or the GPIb-IX-V complex. Further, Gads plays a negligible role in aggregate formation on collagen at an arteriolar rate of shear. In stark contrast, platelets deficient in the adapter LAT exhibit a marked decrease in aggregation and secretion following activation of GPVI and CLEC-2, and are unable to form stable aggregates on collagen at arteriolar shear. CONCLUSIONS The results demonstrate that Gads plays a key role in linking the adapter LAT to SLP-76 in response to weak activation of GPVI and CLEC-2 whereas LAT is required for full activation over a wider range of agonist concentrations. These results reveal the presence of a Gads-independent pathway of platelet activation downstream of LAT.
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Affiliation(s)
- C E Hughes
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, Medical School, University of Birmingham, Birmingham, UK.
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36
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Bezman NA, Lian L, Abrams CS, Brass LF, Kahn ML, Jordan MS, Koretzky GA. Requirements of SLP76 tyrosines in ITAM and integrin receptor signaling and in platelet function in vivo. ACTA ACUST UNITED AC 2008; 205:1775-88. [PMID: 18663126 PMCID: PMC2525600 DOI: 10.1084/jem.20080240] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Src homology 2 domain–containing leukocyte phosphoprotein of 76 kD (SLP76), an adaptor that plays a critical role in platelet activation in vitro, contains three N-terminal tyrosine residues that are essential for its function. We demonstrate that mice containing complementary tyrosine to phenylalanine mutations in Y145 (Y145F) and Y112 and Y128 (Y112/128F) differentially regulate integrin and collagen receptor signaling. We show that mutation of Y145 leads to severe impairment of glycoprotein VI (GPVI)–mediated responses while preserving outside-in integrin signaling. Platelets from Y112/128F mice, although having mild defects in GPVI signaling, exhibit defective actin reorganization after GPVI or αIIbβ3 engagement. The in vivo consequences of these signaling defects correlate with the mild protection from thrombosis seen in Y112/128F mice and the near complete protection observed in Y145F mice. Using genetic complementation, we further demonstrate that all three phosphorylatable tyrosines are required within the same SLP76 molecule to support platelet activation by GPVI.
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Affiliation(s)
- Natalie A Bezman
- Leonard and Madlyn Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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37
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Shin WS, Rockson SG. Animal models for the molecular and mechanistic study of lymphatic biology and disease. Ann N Y Acad Sci 2008; 1131:50-74. [PMID: 18519959 DOI: 10.1196/annals.1413.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The development of animal model systems for the study of the lymphatic system has resulted in an explosion of information regarding the mechanisms governing lymphatic development and the diseases associated with lymphatic dysfunction. Animal studies have led to a new molecular model of embryonic lymphatic vascular development, and have provided insight into the pathophysiology of both inherited and acquired lymphatic insufficiency. It has become apparent, however, that the importance of the lymphatic system to human disease extends, beyond its role in lymphedema, to many other diverse pathologic processes, including, very notably, inflammation and tumor lymphangiogenesis. Here, we have undertaken a systematic review of the models as they relate to molecular and functional characterization of the development, maturation, genetics, heritable and acquired diseases, and neoplastic implications of the lymphatic system. The translation of these advances into therapies for human diseases associated with lymphatic dysfunction will require the continued study of the lymphatic system through robust animal disease models that simulate their human counterparts.
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Affiliation(s)
- William S Shin
- Stanford Center for Lymphatic and Venous Disorders, Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA
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38
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Platelet-derived CD154 enables T-cell priming and protection against Listeria monocytogenes challenge. Blood 2008; 111:3684-91. [PMID: 18256321 DOI: 10.1182/blood-2007-05-091728] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Collagen exposure in tissue activates platelets, initiates wound healing, and modulates adaptive immunity. In this report, data are presented to demonstrate a requirement for platelet-derived CD154 for both collagen-induced augmentation of T-cell immunity and induction of pro-tective immunity to Listeria challenge. Specifically, we demonstrate that Ad5 encoding the membrane-bound form of ovalbumin (Ad5-mOVA) delivered in collagen induces higher ovalbumin-specific cytotoxic T lymphocyte (CTL) activity in a dose-dependent manner compared with Ad5-mOVA delivered in PBS. Increased CTL activity was dependent on the ability of platelets to respond to collagen and to express CD154. Furthermore, mice immunized with low-dose Ad5-mOVA in collagen were able to control a challenge of Listeria monocytogenes recombinant for ovalbumin expression (Lm-OVA), whereas mice immunized with low-dose Ad5-mOVA in PBS were not. These data indicate that in a physiologic setting that mimics wounding, platelets perform a sentinel function when antigen dose is too low to provoke an efficient immune response, and can enhance the generation of antigen-specific CD8 T cells that are functionally relevant to the host.
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39
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Jobe SM, Wilson KM, Leo L, Raimondi A, Molkentin JD, Lentz SR, Di Paola J. Critical role for the mitochondrial permeability transition pore and cyclophilin D in platelet activation and thrombosis. Blood 2008; 111:1257-65. [PMID: 17989312 PMCID: PMC2214770 DOI: 10.1182/blood-2007-05-092684] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 10/27/2007] [Indexed: 02/02/2023] Open
Abstract
Many of the cellular responses that occur in activated platelets resemble events that take place following activation of cell-death pathways in nucleated cells. We tested the hypothesis that formation of the mitochondrial permeability transition pore (MPTP), a key signaling event during cell death, also plays a critical role in platelet activation. Stimulation of murine platelets with thrombin plus the glycoprotein VI agonist convulxin resulted in a rapid loss of mitochondrial transmembrane potential (Deltapsi(m)) in a subpopulation of activated platelets. In the absence of cyclophilin D (CypD), an essential regulator of MPTP formation, murine platelet activation responses were altered. CypD-deficient platelets exhibited defects in phosphatidylserine externalization, high-level surface fibrinogen retention, membrane vesiculation, and procoagulant activity. Also, in CypD-deficient platelet-rich plasma, clot retraction was altered. Stimulation with thrombin plus H(2)O(2), a known activator of MPTP formation, also increased high-level surface fibrinogen retention, phosphatidylserine externalization, and platelet procoagulant activity in a CypD-dependent manner. In a model of carotid artery photochemical injury, thrombosis was markedly accelerated in CypD-deficient mice. These results implicate CypD and the MPTP as critical regulators of platelet activation and suggest a novel CypD-dependent negative-feedback mechanism regulating arterial thrombosis.
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Affiliation(s)
- Shawn M Jobe
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
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40
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Hidano S, Sasanuma H, Ohshima K, Seino KI, Kumar L, Hayashi K, Hikida M, Kurosaki T, Taniguchi M, Geha RS, Kitamura D, Goitsuka R. Distinct regulatory functions of SLP-76 and MIST in NK cell cytotoxicity and IFN-gamma production. Int Immunol 2008; 20:345-52. [PMID: 18203684 DOI: 10.1093/intimm/dxm150] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Activation of NK cells is triggered by multiple receptors. We demonstrate here that SLP-76 is required for CD16- and NKG2D-mediated NK cell cytotoxicity, while MIST negatively regulates these responses in an SLP-76-dependent manner. Exceptionally, MIST acts as a positive regulator of cytotoxicity against YAC-1 cells, although SLP-76 plays a more key role. SLP-76 acts as a dominant positive regulator for both NKG2D-mediated and YAC-1 cell-triggered IFN-gamma production. Although NKG2D-mediated IFN-gamma production depends on phospholipase C (PLC) gamma 2, YAC-1 cell-triggered IFN-gamma production is PLC gamma 2- and Syk/ZAP-70 independent and nuclear factor-kappa B mediated. SLP-76 is required for this process in the presence of MIST but is dispensable in the absence of MIST. Thus, YAC-1 cell-triggered NKG2D-independent IFN-gamma production appears to be regulated by SLP-76-dependent and -independent pathways, in which the latter is negatively regulated by MIST. Taken together, these results suggest that SLP-76 and MIST distinctly but interactively regulate NK cell cytotoxicity and IFN-gamma production.
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Affiliation(s)
- Shinya Hidano
- Division of Development and Aging, Research Institute for Biological Sciences, Tokyo University of Science, Noda, Chiba 278-0022, Japan
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41
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Platelet-mediated modulation of adaptive immunity: unique delivery of CD154 signal by platelet-derived membrane vesicles. Blood 2008; 111:5028-36. [PMID: 18198347 DOI: 10.1182/blood-2007-06-097410] [Citation(s) in RCA: 183] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although mounting evidence indicates that platelets participate in the modulation of both innate and adaptive immunity, the mechanisms by which platelets exert these effects have not been clearly defined. The study reported herein uses a previously documented adoptive transfer model to investigate the ability of platelet-derived membrane vesicles to communicate activation signals to the B-cell compartment. The findings demonstrate for the first time that platelet-derived membrane vesicles are sufficient to deliver CD154 to stimulate antigen-specific IgG production and modulate germinal center formation through cooperation with responses elicited by CD4(+) T cells. The data are consistent with the hypothesis that platelets modulate inflammation and adaptive immunity at sites distant from the location of activation and that platelet-derived membrane vesicles are sufficient to mediate the effect.
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42
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Surin WR, Barthwal MK, Dikshit M. Platelet collagen receptors, signaling and antagonism: Emerging approaches for the prevention of intravascular thrombosis. Thromb Res 2008; 122:786-803. [DOI: 10.1016/j.thromres.2007.10.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 10/17/2007] [Accepted: 10/21/2007] [Indexed: 02/02/2023]
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43
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Ohmori T, Kashiwakura Y, Ishiwata A, Madoiwa S, Mimuro J, Sakata Y. Silencing of a targeted protein in in vivo platelets using a lentiviral vector delivering short hairpin RNA sequence. Arterioscler Thromb Vasc Biol 2007; 27:2266-72. [PMID: 17872456 DOI: 10.1161/atvbaha.107.149872] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Because platelets are anucleate cells having a limited life span, direct gene manipulation cannot in principle be used to investigate the involvement of a specific signal transduction pathway in platelet activation. In this study, we examined whether the expression of a short hairpin RNA (shRNA) sequence in hematopoietic stem cells is maintained during megakaryocyte differentiation, thus resulting in inhibition of targeted protein in platelets. METHODS AND RESULTS To identify platelets derived from transduced stem cells, we generated a lentiviral vector that simultaneously expresses the shRNA sequence driven by the U6 promoter and GFP under the control of the glycoprotein (GP) Ib alpha promoter. Transplantation of mouse bone marrow cells transduced with the vector facilitated specifically mark platelets derived from the transduced cells. Transplantation of cells transduced with shRNA sequence targeting integrin alphaIIb caused a significant reduction of integrin alphaIIb beta3 (alphaIIb beta3) expression in GFP-positive platelets. It also inhibited alphaIIb beta3 activation assessed by the binding of JON/A, an antibody that recognizes activated alphaIIb beta3. Talin-1 silencing by the same method resulted in normal alphaIIb beta3 expression but deficient inside-out alphaIIb beta3 signaling. CONCLUSIONS shRNA expression driven by the U6 promoter is preserved during megakaryopoiesis. This method facilitates functional analysis of targeted protein in platelet activation.
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Affiliation(s)
- Tsukasa Ohmori
- Research Division of Cell and Molecular Medicine, Center for Molecular Medicine, Jichi Medical University School of Medicine, 3111-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
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44
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Abstract
Adapters are multidomain molecules that recruit effector proteins during signal transduction by immunoreceptors and integrins. The absence of these scaffolding molecules profoundly affects development and function of various hematopoietic lineages, underscoring their importance as regulators of signaling cascades. An emerging aspect of the mechanism by which engaged immunoreceptors and integrins transmit signals within the cell is by differential usage of various adapters that function to nucleate formation of distinct signaling complexes in a specific location within the cell. In this review, we discuss the mechanisms by which adapter proteins coordinate signal transduction with an emphasis on the role of subcellular compartmentalization in adapter function.
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Affiliation(s)
- Natalie Bezman
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
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45
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Abstract
Stable platelet adhesion to extracellular matrices and the formation of a hemostatic or pathological thrombus are dependent on integrin alphaIIbbeta3, also known as GPIIb-IIIa. However, maximal platelet responses to vascular injury may involve the participation of other integrins expressed in platelets (alphaVbeta3, alpha2beta1, alpha5beta1, and alpha6beta1). Platelet membrane 'immunoreceptors' contain at least one subunit with an extracellular immunoglobulin superfamily domain and/or an intracellular stimulatory immunoreceptor tyrosine-based activation motif (ITAM) or immunoreceptor tyrosine-based inhibitory motif (ITIM). Platelet ITAM receptors, such as FcgammaRIIA and the GPVI-FcRgamma complex, promote activation of integrins, while ITIM receptors, such as platelet-endothelial cell adhesion molecule-1, may promote their inhibition. This review summarizes the structure and function of platelet integrins and immunoreceptors, the emerging functional relationships between these receptor classes, and the consequences of their interaction for platelet function in hemostasis and thrombosis.
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Affiliation(s)
- Ana Kasirer-Friede
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0726, USA.
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46
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Ragab A, Séverin S, Gratacap MP, Aguado E, Malissen M, Jandrot-Perrus M, Malissen B, Ragab-Thomas J, Payrastre B. Roles of the C-terminal tyrosine residues of LAT in GPVI-induced platelet activation: insights into the mechanism of PLC gamma 2 activation. Blood 2007; 110:2466-74. [PMID: 17579183 DOI: 10.1182/blood-2007-02-075432] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Linker for activation of T cells (LAT) is an adaptor protein required for organization of the signaling machinery downstream of the platelet collagen receptor, the glycoprotein VI (GPVI). Here, we investigated the effect of LAT mutations on specific signaling pathways and on platelet functions in response to GPVI triggering by convulxin (Cvx). Using mice containing tyrosine to phenylalanine mutations of the adaptor, we show the crucial role played by the tyrosine residues at positions 175, 195, and 235 in the phosphorylation of LAT and in the whole pattern of protein tyrosine phosphorylation in response to Cvx. These 3 C-terminal tyrosine residues are important to recruit the tyrosine kinase Fyn, which may be involved in LAT phosphorylation. Efficient phosphoinositide 3-kinase (PI3K) activation requires the 3 C-terminal tyrosine residues of LAT but not its tyrosine 136. Interestingly, single mutation of the tyrosine 136 results in the loss of phospholipase C gamma2 (PLCgamma2) activation without affecting its PI3K-dependent membrane association, and is sufficient to impair platelet responses to Cvx. Thus, activation of PLCgamma2 via GPVI is dependent on 2 complementary events: its interaction with the tyrosine 136 of LAT and its membrane location, which itself requires events mediated by the 3 C-terminal tyrosines of LAT.
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Affiliation(s)
- Ashraf Ragab
- Institut National de la Santé et de la Recherche Médicale (INSERM), U563, Centre de Physiopathologie de Toulouse Purpan, Département Oncogenèse, Signalisation et Innovation Thérapeutique, Toulouse, France
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47
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Clemens RA, Lenox LE, Kambayashi T, Bezman N, Maltzman JS, Nichols KE, Koretzky GA. Loss of SLP-76 expression within myeloid cells confers resistance to neutrophil-mediated tissue damage while maintaining effective bacterial killing. THE JOURNAL OF IMMUNOLOGY 2007; 178:4606-14. [PMID: 17372019 DOI: 10.4049/jimmunol.178.7.4606] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The Src homology 2 domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76) is an adaptor molecule critical for immunoreceptor and integrin signaling in multiple hemopoietic lineages. We showed previously that SLP-76 is required for neutrophil function in vitro, including integrin-induced adhesion and production of reactive oxygen intermediates, and to a lesser extent, FcgammaR-induced calcium flux and reactive oxygen intermediate production. It has been difficult to determine whether SLP-76 regulates neutrophil responses in vivo, because Slp-76(-/-) mice exhibit marked defects in thymocyte and vascular development, as well as platelet and mast cell function. To circumvent these issues, we generated mice with targeted loss of SLP-76 expression within myeloid cells. Neutrophils obtained from these animals failed to respond to integrin activation in vitro, similar to Slp-76(-/-) cells. Despite these abnormalities, SLP-76-deficient neutrophils migrated normally in vivo in response to Staphylococcus aureus infection and efficiently cleared micro-organisms. Interestingly, SLP-76-deficient neutrophils did not induce a robust inflammatory response in the localized Shwartzman reaction. Collectively, these data suggest that disruption of integrin signaling via loss of SLP-76 expression differentially impairs neutrophil functions in vivo, with preservation of migration and killing of S. aureus but reduction in LPS-induced tissue damage and vascular injury.
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Affiliation(s)
- Regina A Clemens
- Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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48
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Jirouskova M, Shet AS, Johnson GJ. A guide to murine platelet structure, function, assays, and genetic alterations. J Thromb Haemost 2007; 5:661-9. [PMID: 17403200 DOI: 10.1111/j.1538-7836.2007.02407.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Platelets play an important role in hemostasis, thrombosis and several other biological processes. The adaptability of mice to genetic manipulation and their genetic similarity to humans has resulted in a plethora of murine models to study platelet function. Although murine platelets differ from human platelets with regard to size, number and structure, functionally they are very similar. Thus, studies which employed these model systems have greatly improved our current understanding of the contribution of platelets to hemostasis and thrombosis. This review presents general recommendations with respect to collection, isolation and processing of murine platelets. It also describes the assays currently available to study platelet function and critically assesses their utility. The extensive literature on the effects of genetic alterations on murine platelet function is considered in detail. This review is intended to provide a convenient source of reference for platelet investigators.
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Affiliation(s)
- M Jirouskova
- Laboratory of Blood and Vascular Biology, Rockefeller University, NY, USA
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49
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Fuller GL, Williams JA, Tomlinson MG, Eble JA, Hanna SL, Pöhlmann S, Suzuki-Inoue K, Ozaki Y, Watson SP, Pearce AC. The C-type lectin receptors CLEC-2 and Dectin-1, but not DC-SIGN, signal via a novel YXXL-dependent signaling cascade. J Biol Chem 2007; 282:12397-409. [PMID: 17339324 PMCID: PMC1997429 DOI: 10.1074/jbc.m609558200] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The two lectin receptors, CLEC-2 and Dectin-1, have been shown to signal through a Syk-dependent pathway, despite the presence of only a single YXXL in their cytosolic tails. In this study, we show that stimulation of CLEC-2 in platelets and in two mutant cell lines is dependent on the YXXL motif and on proteins that participate in signaling by immunoreceptor tyrosine-based activation motif receptors, including Src, Syk, and Tec family kinases, and on phospholipase Cgamma. Strikingly, mutation of either Src homology (SH) 2 domain of Syk blocks signaling by CLEC-2 despite the fact that it has only a single YXXL motif. Furthermore, signaling by CLEC-2 is only partially dependent on the BLNK/SLP-76 family of adapter proteins in contrast to that of immunoreceptor tyrosine-based activation motif receptors. The C-type lectin receptor, Dectin-1, which contains a YXXL motif preceded by the same four amino acids as for CLEC-2 (DEDG), signals like CLEC-2 and also requires the two SH2 domains of Syk and is only partially dependent on the BLNK/SLP-76 family of adapters. In marked contrast, the C-type lectin receptor, DC-SIGN, which has a distinct series of amino acids preceding a single YXXL, signals independent of this motif. A mutational analysis of the DEDG sequence of CLEC-2 revealed that the glycine residue directly upstream of the YXXL tyrosine is important for CLEC-2 signaling. These results demonstrate that CLEC-2 and Dectin-1 signal through a single YXXL motif that requires the tandem SH2 domains of Syk but is only partially dependent on the SLP-76/BLNK family of adapters.
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Affiliation(s)
- Gemma L.J. Fuller
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Jennifer A.E. Williams
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Michael G. Tomlinson
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Johannes A. Eble
- Institute for Physiological Chemistry and Pathobiochemistry, Muenster University Hospital, Muenster, Germany
| | - Sheri L. Hanna
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Stefan Pöhlmann
- Institute for Clinical and Molecular Virology, University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Katsue Suzuki-Inoue
- Department of Clinical and Laboratory Medicine, University of Yamanashi, 1110 Shimokato Tamaho Nakakoma, Yamanashi 409-3898, Japan
| | - Yukio Ozaki
- Department of Clinical and Laboratory Medicine, University of Yamanashi, 1110 Shimokato Tamaho Nakakoma, Yamanashi 409-3898, Japan
| | - Steve P. Watson
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Andrew C. Pearce
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
- Corresponding author: Dr Andrew C. Pearce, Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK; Tel: +44 121 415 8679; Fax: +44 121 415 8817; E-mail:
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50
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Lee DH, Blajchman MA. Animal Models. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50795-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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