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Xue J, Deng J, Qin H, Yan S, Zhao Z, Qin L, Liu J, Wang H. The interaction of platelet-related factors with tumor cells promotes tumor metastasis. J Transl Med 2024; 22:371. [PMID: 38637802 PMCID: PMC11025228 DOI: 10.1186/s12967-024-05126-6] [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: 01/16/2024] [Accepted: 03/22/2024] [Indexed: 04/20/2024] Open
Abstract
Platelets not only participate in thrombosis and hemostasis but also interact with tumor cells and protect them from mechanical damage caused by hemodynamic shear stress and natural killer cell lysis, thereby promoting their colonization and metastasis to distant organs. Platelets can affect the tumor microenvironment via interactions between platelet-related factors and tumor cells. Metastasis is a key event in cancer-related death and is associated with platelet-related factors in lung, breast, and colorectal cancers. Although the factors that promote platelet expression vary slightly in terms of their type and mode of action, they all contribute to the overall process. Recognizing the correlation and mechanisms between these factors is crucial for studying the colonization of distant target organs and developing targeted therapies for these three types of tumors. This paper reviews studies on major platelet-related factors closely associated with metastasis in lung, breast, and colorectal cancers.
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Affiliation(s)
- Jie Xue
- Department of Blood Transfusion, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Shinan District, Qingdao, 266000, Shandong, China
- Department of Blood Transfusion, The Central Hospital of Qingdao Jiaozhou, 99 Yunxi River South Road, Qingdao, 266300, Shandong, China
| | - Jianzhao Deng
- Clinical Laboratory, The Central Hospital of Qingdao Jiaozhou, 99 Yunxi River South Road, Qingdao, 266300, Shandong, China
| | - Hongwei Qin
- Department of Blood Transfusion, The Central Hospital of Qingdao Jiaozhou, 99 Yunxi River South Road, Qingdao, 266300, Shandong, China
| | - Songxia Yan
- Department of Blood Transfusion, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Shinan District, Qingdao, 266000, Shandong, China
| | - Zhen Zhao
- Department of Blood Transfusion, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Shinan District, Qingdao, 266000, Shandong, China
| | - Lifeng Qin
- Department of Blood Transfusion, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Shinan District, Qingdao, 266000, Shandong, China
| | - Jiao Liu
- Department of Blood Transfusion, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Shinan District, Qingdao, 266000, Shandong, China
| | - Haiyan Wang
- Department of Blood Transfusion, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Shinan District, Qingdao, 266000, Shandong, China.
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2
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Janus-Bell E, Mangin PH. The relative importance of platelet integrins in hemostasis, thrombosis and beyond. Haematologica 2023; 108:1734-1747. [PMID: 36700400 PMCID: PMC10316258 DOI: 10.3324/haematol.2022.282136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 01/09/2023] [Indexed: 01/27/2023] Open
Abstract
Integrins are heterodimeric transmembrane receptors composed of α and β chains, with an N-terminal extracellular domain forming a globular head corresponding to the ligand binding site. Integrins regulate various cellular functions including adhesion, migration, proliferation, spreading and apoptosis. On platelets, integrins play a central role in adhesion and aggregation on subendothelial matrix proteins of the vascular wall, thereby ensuring hemostasis. Platelet integrins belong either to the β1 family (α2β1, α5β1 and α6β1) or to the β3 family (αIIbβ3 and αvβ3). On resting platelets, integrins can engage their ligands when the latter are immobilized but not in their soluble form. The effects of various agonists promote an inside-out signal in platelets, increasing the affinity of integrins for their ligands and conveying a modest signal reinforcing platelet activation, called outside-in signaling. This outside-in signal ensures platelet adhesion, shape change, granule secretion and aggregation. In this review, we examine the role of each platelet integrin in hemostatic plug formation, hemostasis and arterial thrombosis and also beyond these classical functions, notably in tumor metastasis and sepsis.
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Affiliation(s)
- Emily Janus-Bell
- Université de Strasbourg, INSERM, EFS Grand-Est, BPPS UMR-S1255, FMTS, F-67065 Strasbourg.
| | - Pierre H Mangin
- Université de Strasbourg, INSERM, EFS Grand-Est, BPPS UMR-S1255, FMTS, F-67065 Strasbourg
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3
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O’Sullivan LR, Cahill MR, Young PW. The Importance of Alpha-Actinin Proteins in Platelet Formation and Function, and Their Causative Role in Congenital Macrothrombocytopenia. Int J Mol Sci 2021; 22:9363. [PMID: 34502272 PMCID: PMC8431150 DOI: 10.3390/ijms22179363] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/04/2022] Open
Abstract
The actin cytoskeleton plays a central role in platelet formation and function. Alpha-actinins (actinins) are actin filament crosslinking proteins that are prominently expressed in platelets and have been studied in relation to their role in platelet activation since the 1970s. However, within the past decade, several groups have described mutations in ACTN1/actinin-1 that cause congenital macrothrombocytopenia (CMTP)-accounting for approximately 5% of all cases of this condition. These findings are suggestive of potentially novel functions for actinins in platelet formation from megakaryocytes in the bone marrow and/or platelet maturation in circulation. Here, we review some recent insights into the well-known functions of actinins in platelet activation before considering possible roles for actinins in platelet formation that could explain their association with CMTP. We describe what is known about the consequences of CMTP-linked mutations on actinin-1 function at a molecular and cellular level and speculate how these changes might lead to the alterations in platelet count and morphology observed in CMTP patients. Finally, we outline some unanswered questions in this area and how they might be addressed in future studies.
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Affiliation(s)
- Leanne R. O’Sullivan
- School of Biochemistry & Cell Biology, University College Cork, T12 XF62 Cork, Ireland;
| | - Mary R. Cahill
- Department of Haematology and CancerResearch@UCC, Cork University Hospital, University College Cork, T12 XF62 Cork, Ireland;
| | - Paul W. Young
- School of Biochemistry & Cell Biology, University College Cork, T12 XF62 Cork, Ireland;
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4
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Bioactive Ether Lipids: Primordial Modulators of Cellular Signaling. Metabolites 2021; 11:metabo11010041. [PMID: 33430006 PMCID: PMC7827237 DOI: 10.3390/metabo11010041] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/01/2021] [Accepted: 01/03/2021] [Indexed: 12/14/2022] Open
Abstract
The primacy of lipids as essential components of cellular membranes is conserved across taxonomic domains. In addition to this crucial role as a semi-permeable barrier, lipids are also increasingly recognized as important signaling molecules with diverse functional mechanisms ranging from cell surface receptor binding to the intracellular regulation of enzymatic cascades. In this review, we focus on ether lipids, an ancient family of lipids having ether-linked structures that chemically differ from their more prevalent acyl relatives. In particular, we examine ether lipid biosynthesis in the peroxisome of mammalian cells, the roles of selected glycerolipids and glycerophospholipids in signal transduction in both prokaryotes and eukaryotes, and finally, the potential therapeutic contributions of synthetic ether lipids to the treatment of cancer.
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5
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Abstract
Simple Summary Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment. Abstract Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.
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O'Sullivan LR, Ajaykumar AP, Dembicka KM, Murphy A, Grennan EP, Young PW. Investigation of calmodulin-like and rod domain mutations suggests common molecular mechanism for α-actinin-1-linked congenital macrothrombocytopenia. FEBS Lett 2019; 594:161-174. [PMID: 31365757 DOI: 10.1002/1873-3468.13562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/22/2019] [Accepted: 07/29/2019] [Indexed: 11/11/2022]
Abstract
Actinin-1 mutations cause dominantly inherited congenital macrothrombocytopenia (CMTP), with mutations in the actin-binding domain increasing actinin's affinity for F-actin. In this study, we examined nine CMTP-causing mutations in the calmodulin-like and rod domains of actinin-1. These mutations increase, to varying degrees, actinin's ability to bundle actin filaments in vitro. Mutations within the calmodulin-like domain decrease its thermal stability slightly but do not dramatically affect calcium binding, with mutant proteins retaining calcium-dependent regulation of filament bundling in vitro. The G764S and E769K mutations increase cytoskeletal association of actinin in cells, and all mutant proteins colocalize with F-actin in cultured HeLa cells. Thus, CMTP-causing actinin-1 mutations outside the actin-binding domain also increase actin association, suggesting a common molecular mechanism underlying actinin-1 related CMTP.
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Affiliation(s)
- Leanne Rose O'Sullivan
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland
| | | | - Kornelia Maria Dembicka
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland
| | - Aidan Murphy
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland
| | - Eamonn Paul Grennan
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland
| | - Paul William Young
- School of Biochemistry and Cell Biology, Western Gateway Building, University College Cork, Cork, Ireland
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7
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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: 208] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 02/21/2019] [Indexed: 12/18/2022] Open
Abstract
Integrins are a family of transmembrane glycoprotein signaling receptors that can transmit bioinformation bidirectionally across the plasma membrane. Integrin αIIbβ3 is expressed at a high level in platelets and their progenitors, where it plays a central role in platelet functions, hemostasis, and arterial thrombosis. Integrin αIIbβ3 also participates in cancer progression, such as tumor cell proliferation and metastasis. In resting platelets, integrin αIIbβ3 adopts an inactive conformation. Upon agonist stimulation, the transduction of inside-out signals leads integrin αIIbβ3 to switch from a low- to high-affinity state for fibrinogen and other ligands. Ligand binding causes integrin clustering and subsequently promotes outside-in signaling, which initiates and amplifies a range of cellular events to drive essential platelet functions such as spreading, aggregation, clot retraction, and thrombus consolidation. Regulation of the bidirectional signaling of integrin αIIbβ3 requires the involvement of numerous interacting proteins, which associate with the cytoplasmic tails of αIIbβ3 in particular. Integrin αIIbβ3 and its signaling pathways are considered promising targets for antithrombotic therapy. This review describes the bidirectional signal transduction of integrin αIIbβ3 in platelets, as well as the proteins responsible for its regulation and therapeutic agents that target integrin αIIbβ3 and its signaling pathways.
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Affiliation(s)
- Jiansong Huang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xia Li
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaofeng Shi
- Department of Hematology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Mark Zhu
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jinghan Wang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shujuan Huang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xin Huang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Huafeng Wang
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Department of Hematological Malignancies Translational Science, Gehr Family Center for Leukemia Research, Hematologic Malignancies and Stem Cell Transplantation Institute, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, 91010, USA
| | - Ling Li
- Department of Hematological Malignancies Translational Science, Gehr Family Center for Leukemia Research, Hematologic Malignancies and Stem Cell Transplantation Institute, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, 91010, USA
| | - Huan Deng
- Department of Pathology, The Fourth Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yulan Zhou
- Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Jianhua Mao
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Sino-French Research Centre for Life Sciences and Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhangbiao Long
- Department of Hematology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Zhixin Ma
- Clinical Prenatal Diagnosis Center, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Wenle Ye
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jiajia Pan
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China.,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaodong Xi
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Sino-French Research Centre for Life Sciences and Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jie Jin
- Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. .,Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China. .,Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
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8
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Wan H, Xie T, Xu Q, Hu X, Xing S, Yang H, Gao Y, He Z. Thy-1 depletion and integrin β3 upregulation-mediated PI3K-Akt-mTOR pathway activation inhibits lung fibroblast autophagy in lipopolysaccharide-induced pulmonary fibrosis. J Transl Med 2019; 99:1636-1649. [PMID: 31249375 PMCID: PMC7102294 DOI: 10.1038/s41374-019-0281-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/13/2019] [Accepted: 05/02/2019] [Indexed: 12/24/2022] Open
Abstract
Lipopolysaccharide (LPS)-induced autophagy inhibition in lung fibroblasts is closely associated with the activation of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K-Akt-mTOR) pathway. However, the underlying mechanism remains unknown. In this study, we demonstrated that LPS activated the PI3K-Akt-mTOR pathway and inhibited lung fibroblast autophagy by depleting thymocyte differentiation antigen-1 (Thy-1) and upregulating integrin β3 (Itgb3). Challenge of the human lung fibroblast MRC-5 cell line with LPS resulted in significant upregulation of integrin β3, activation of the PI3K-Akt-mTOR pathway and inhibition of autophagy, which could be abolished by integrin β3 silencing by specific shRNA or treatment with the integrin β3 inhibitor cilengitide. Meanwhile, LPS could inhibit Thy-1 expression accompanied with PI3K-Akt-mTOR pathway activation and lung fibroblast autophagy inhibition; these effects could be prevented by Thy-1 overexpression. Meanwhile, Thy-1 downregulation with Thy-1 shRNA could mimic the effects of LPS, inducing the activation of PI3K-Akt-mTOR pathway and inhibiting lung fibroblast autophagy. Furthermore, protein immunoprecipitation analysis demonstrated that LPS reduced the binding of Thy-1 to integrin β3. Thy-1 downregulation, integrin β3 upregulation and autophagy inhibition were also detected in a mouse model of LPS-induced pulmonary fibrosis, which could be prohibited by intratracheal injection of Thy-1 overexpressing adeno-associated virus (AAV) or intraperitoneal injection of the integrin β3 inhibitor cilengitide. In conclusion, this study demonstrated that Thy-1 depletion and integrin β3 upregulation are involved in LPS-induced pulmonary fibrosis, and may serve as potential therapeutic targets for pulmonary fibrosis.
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Affiliation(s)
- Hanxi Wan
- 0000 0004 0368 8293grid.16821.3cDepartment of Critical Care Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 200127 Shanghai, China
| | - Tingting Xie
- 0000 0004 0368 8293grid.16821.3cDepartment of Critical Care Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 200127 Shanghai, China
| | - Qiaoyi Xu
- 0000 0004 0368 8293grid.16821.3cDepartment of Critical Care Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 200127 Shanghai, China
| | - Xiaoting Hu
- 0000 0004 0368 8293grid.16821.3cDepartment of Critical Care Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 200127 Shanghai, China
| | - Shunpeng Xing
- 0000 0004 0368 8293grid.16821.3cDepartment of Critical Care Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 200127 Shanghai, China
| | - Hao Yang
- 0000000123704535grid.24516.34Department of Anesthesiology, Shanghai Pulmonary Hospital, Tongji University School of Medicine, 200433 Shanghai, China
| | - Yuan Gao
- Department of Critical Care Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 200127, Shanghai, China.
| | - Zhengyu He
- Department of Critical Care Medicine, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 200127, Shanghai, China.
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9
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Pan L, Zhao Y, Farouk MH, Bao N, Wang T, Qin G. Integrins Were Involved in Soybean Agglutinin Induced Cell Apoptosis in IPEC-J2. Int J Mol Sci 2018; 19:E587. [PMID: 29462933 PMCID: PMC5855809 DOI: 10.3390/ijms19020587] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 02/02/2018] [Accepted: 02/09/2018] [Indexed: 12/30/2022] Open
Abstract
Soybean agglutinin (SBA), is a non-fiber carbohydrate related protein and a major anti-nutritional factor. Integrins, transmembrane glycoproteins, are involved in many biological processes. Although recent work suggested that integrins are involved in SBA-induced cell-cycle alterations, no comprehensive study has reported whether integrins are involved in SBA-induced cell apoptosis (SCA) in IPEC-J2. The relationship between SBA and integrins are still unclear. We aimed to elucidate the effects of SBA on IPEC-J2 cell proliferation and cell apoptosis; to study the roles of integrins in IPEC-J2 normal cell apoptosis (NCA) and SCA; and to illustrate the relationship and connection type between SBA and integrins. Thus, IPEC-J2 cells were treated with SBA at the levels of 0, 0.125, 0.25, 0.5, 1.0 or 2.0 mg/mL to determine cell proliferation and cell apoptosis. The cells were divided into control, SBA treated groups, integrin inhibitor groups, and SBA + integrin inhibitor groups to determine the integrin function in SCA. The results showed that SBA significantly (p < 0.05) lowered cell proliferation and induced cell apoptosis in IPEC-J2 (p < 0.05). Inhibition of any integrin type induced the cell apoptosis (p < 0.05) and these integrins were involved in SCA (p < 0.05). Even SBA had no physical connection with integrins, an association was detected between SBA and α-actinin-2 ACTN2 (integrin-binding protein). Additionally, SBA reduced the mRNA expression of integrins by down regulating the gene expression level of ACTN2. We concluded an evidence for the anti-nutritional mechanism of SBA by ACTN2 with integrins. Further trials are needed to prove whether ACTN2 is the only protein for connecting SBA with integrin.
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Affiliation(s)
- Li Pan
- Key Laboratory of Animal Production, Product Quality and Security, Ministry of Education, Key Laboratory of Animal Nutrition and Feed Science, Jilin Province, College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Yuan Zhao
- Key Laboratory of Animal Production, Product Quality and Security, Ministry of Education, Key Laboratory of Animal Nutrition and Feed Science, Jilin Province, College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Mohamed Hamdy Farouk
- Key Laboratory of Animal Production, Product Quality and Security, Ministry of Education, Key Laboratory of Animal Nutrition and Feed Science, Jilin Province, College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
- Department of Animal Production, Faculty of Agriculture, Al-Azhar University, Nasr City, Cairo 11884, Egypt.
| | - Nan Bao
- Key Laboratory of Animal Production, Product Quality and Security, Ministry of Education, Key Laboratory of Animal Nutrition and Feed Science, Jilin Province, College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Tao Wang
- Key Laboratory of Animal Production, Product Quality and Security, Ministry of Education, Key Laboratory of Animal Nutrition and Feed Science, Jilin Province, College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Guixin Qin
- Key Laboratory of Animal Production, Product Quality and Security, Ministry of Education, Key Laboratory of Animal Nutrition and Feed Science, Jilin Province, College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
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10
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Affiliation(s)
- Sarah K Westbury
- a School of Clinical Sciences, University of Bristol , Bristol , UK
| | | | - Andrew D Mumford
- c School of Cellular and Molecular Medicine, University of Bristol , Bristol , UK
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11
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Shams H, Mofrad MRK. α-Actinin Induces a Kink in the Transmembrane Domain of β 3-Integrin and Impairs Activation via Talin. Biophys J 2017; 113:948-956. [PMID: 28834730 PMCID: PMC5567591 DOI: 10.1016/j.bpj.2017.06.064] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 06/18/2017] [Accepted: 06/28/2017] [Indexed: 01/09/2023] Open
Abstract
Integrin-mediated signaling is crucial for cell-substrate adhesion and can be triggered from both intra- and extracellular interactions. Although talin binding is sufficient for inside-out activation of integrin, other cytoplasmic proteins such as α-actinin and filamin can directly interfere with talin-mediated integrin activation. Specifically, α-actinin plays distinct roles in regulating αIIbβ3 versus α5β1 integrin. It has been shown that α-actinin competes with talin for binding to the cytoplasmic tail of β3-integrin, whereas it cooperates with talin for activating integrin α5β1. In this study, molecular dynamics simulations were employed to compare and contrast molecular mechanisms of αIIbβ3 and α5β1 activation in the presence and absence of α-actinin. Our results suggest that α-actinin impairs integrin signaling by both undermining talin binding to the β3-integrin cytoplasmic tail and inducing a kink in the transmembrane domain of β3-integrin. Furthermore, we showed that α-actinin promote talin association with β1-integrin by restricting the motion of the cytoplasmic tail and reducing the entropic barrier for talin binding. Taken together, our results showed that the interplay between talin and α-actinin regulates signal transmission via controlling the conformation of the transmembrane domain and altering natural response modes of integrins in a type-specific manner.
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Affiliation(s)
- Hengameh Shams
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California.
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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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Thomas SG, Poulter NS, Bem D, Finney B, Machesky LM, Watson SP. The actin binding proteins cortactin and HS1 are dispensable for platelet actin nodule and megakaryocyte podosome formation. Platelets 2017; 28:372-379. [PMID: 27778524 PMCID: PMC5274539 DOI: 10.1080/09537104.2016.1235688] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/06/2016] [Accepted: 08/22/2016] [Indexed: 11/08/2022]
Abstract
A dynamic, properly organised actin cytoskeleton is critical for the production and haemostatic function of platelets. The Wiskott Aldrich Syndrome protein (WASp) and Actin-Related Proteins 2 & 3 Complex (Arp2/3 complex) are critical mediators of actin polymerisation and organisation in many cell types. In platelets and megakaryocytes, these proteins have been shown to be important for proper platelet production and function. The cortactin family of proteins (Cttn & HS1) are known to regulate WASp-Arp2/3-mediated actin polymerisation in other cell types and so here we address the role of these proteins in platelets using knockout mouse models. We generated mice lacking Cttn and HS1 in the megakaryocyte/platelet lineage. These mice had normal platelet production, with platelet number, size and surface receptor profile comparable to controls. Platelet function was also unaffected by loss of Cttn/HS1 with no differences observed in a range of platelet function assays including aggregation, secretion, spreading, clot retraction or tyrosine phosphorylation. No effect on tail bleeding time or in thrombosis models was observed. In addition, platelet actin nodules, and megakaryocyte podosomes, actin-based structures known to be dependent on WASp and the Arp2/3 complex, formed normally. We conclude that despite the importance of WASp and the Arp2/3 complex in regulating F-actin dynamics in many cells types, the role of cortactin in their regulation appears to be fulfilled by other proteins in platelets.
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Affiliation(s)
- Steven G. Thomas
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Natalie S. Poulter
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Danai Bem
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Brenda Finney
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Laura M. Machesky
- Cancer Research UK Beatson Institute, College of Medical. Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Stephen P. Watson
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
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14
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Taylor KA, Pugh N. The contribution of zinc to platelet behaviour during haemostasis and thrombosis. Metallomics 2016; 8:144-55. [PMID: 26727074 DOI: 10.1039/c5mt00251f] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Platelets are the primary cellular determinants of haemostasis and pathological thrombus formation leading to myocardial infarction and stroke. Following vascular injury or atherosclerotic plaque rupture, platelets are recruited to sites of damage and undergo activation induced by a variety of soluble and/or insoluble agonists. Platelet activation is a multi-step process culminating in the formation of thrombi, which contribute to the haemostatic process. Zinc (Zn(2+)) is acknowledged as an important signalling molecule in a diverse range of cellular systems, however there is limited understanding of the influence of Zn(2+) on platelet behaviour during thrombus formation. This review evaluates the contributions of exogenous and intracellular Zn(2+) to platelet function and assesses the potential pathophysiological implications of Zn(2+) signalling. We also provide a speculative assessment of the mechanisms by which platelets could respond to changes in extracellular and intracellular Zn(2+) concentration.
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Affiliation(s)
- K A Taylor
- Department of Biomedical and Forensic Sciences, Faculty of Science and Technology, Anglia Ruskin University, Cambridge, CB1 1PT, UK.
| | - N Pugh
- Department of Biomedical and Forensic Sciences, Faculty of Science and Technology, Anglia Ruskin University, Cambridge, CB1 1PT, UK.
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15
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Human CalDAG-GEFI deficiency increases bleeding and delays αIIbβ3 activation. Blood 2016; 128:2729-2733. [PMID: 27663674 DOI: 10.1182/blood-2016-03-704825] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 09/17/2016] [Indexed: 11/20/2022] Open
Abstract
Affinity regulation of integrin αIIbβ3 for fibrinogen by inside-out signaling plays a critical role in hemostasis. Calcium and diacylglycerol (DAG)-regulated guanine nucleotide exchange factor I (CalDAG-GEFI) was identified as a Rap1-activating molecule, and its role in inside-out αIIbβ3 activation was established in CalDAG-GEFI-deficient mice. However, little information regarding CalDAG-GEFI in human platelets is available. Here, we report a 16-year-old girl with CalDAG-GEFI deficiency who has been suffering from severe bleeding tendency. Although talin and kindlin-3 were normally detected, CalDAG-GEFI was undetectable in her platelets by western blotting. Genetic analysis revealed compound heterozygous CalDAG-GEFI mutations, Lys309X and Leu360del, which were responsible for CalDAG-GEFI deficiency. The functional analysis demonstrated impaired αIIbβ3 activation by various agonists except for phorbol myristate acetate, normal calcium mobilization, and impaired Rap1 activation, which were consistent with the phenotype of CalDAG-GEFI-deficient mice. Despite substantial αIIbβ3 activation at high agonist concentrations, she had severe bleeding tendency. Further functional analysis demonstrated markedly delayed αIIbβ3 activation velocity and decreased shear-induced thrombus formation. Contrary to CalDAG-GEFI-deficient mice, which showed integrin-dependent neutrophil functional abnormality, neutrophil β2 integrin activation was not impaired in the patient. Our results demonstrate the critical role of CalDAG-GEFI in rapid αIIbβ3 activation of human platelets.
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16
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Differences in intracellular calcium dynamics cause differences in α-granule secretion and phosphatidylserine expression in platelets adhering on glass and TiO2. Biointerphases 2016; 11:029807. [DOI: 10.1116/1.4947047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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17
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Shams H, Golji J, Garakani K, Mofrad MRK. Dynamic Regulation of α-Actinin's Calponin Homology Domains on F-Actin. Biophys J 2016; 110:1444-55. [PMID: 27028653 PMCID: PMC4816760 DOI: 10.1016/j.bpj.2016.02.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 01/22/2016] [Accepted: 02/01/2016] [Indexed: 11/24/2022] Open
Abstract
α-Actinin is an essential actin cross-linker involved in cytoskeletal organization and dynamics. The molecular conformation of α-actinin's actin-binding domain (ABD) regulates its association with actin and thus mutations in this domain can lead to severe pathogenic conditions. A point mutation at lysine 255 in human α-actinin-4 to glutamate increases the binding affinity resulting in stiffer cytoskeletal structures. The role of different ABD conformations and the effect of K255E mutation on ABD conformations remain elusive. To evaluate the impact of K255E mutation on ABD binding to actin we use all-atom molecular dynamics and free energy calculation methods and study the molecular mechanism of actin association in both wild-type α-actinin and in the K225E mutant. Our models illustrate that the strength of actin association is indeed sensitive to the ABD conformation, predict the effect of K255E mutation--based on simulations with the K237E mutant chicken α-actinin--and evaluate the mechanism of α-actinin binding to actin. Furthermore, our simulations showed that the calmodulin domain binding to the linker region was important for regulating the distance between actin and ABD. Our results provide valuable insights into the molecular details of this critical cellular phenomenon and further contribute to an understanding of cytoskeletal dynamics in health and disease.
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Affiliation(s)
- Hengameh Shams
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California
| | - Javad Golji
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California
| | - Kiavash Garakani
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California; Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California.
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18
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19
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Reviakine I. New horizons in platelet research: Understanding and harnessing platelet functional diversity. Clin Hemorheol Microcirc 2015; 60:133-52. [DOI: 10.3233/ch-151942] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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20
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Poulter NS, Pollitt AY, Davies A, Malinova D, Nash GB, Hannon MJ, Pikramenou Z, Rappoport JZ, Hartwig JH, Owen DM, Thrasher AJ, Watson SP, Thomas SG. Platelet actin nodules are podosome-like structures dependent on Wiskott-Aldrich syndrome protein and ARP2/3 complex. Nat Commun 2015; 6:7254. [PMID: 26028144 PMCID: PMC4458878 DOI: 10.1038/ncomms8254] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/21/2015] [Indexed: 11/09/2022] Open
Abstract
The actin nodule is a novel F-actin structure present in platelets during early spreading. However, only limited detail is known regarding nodule organization and function. Here we use electron microscopy, SIM and dSTORM super-resolution, and live-cell TIRF microscopy to characterize the structural organization and signalling pathways associated with nodule formation. Nodules are composed of up to four actin-rich structures linked together by actin bundles. They are enriched in the adhesion-related proteins talin and vinculin, have a central core of tyrosine phosphorylated proteins and are depleted of integrins at the plasma membrane. Nodule formation is dependent on Wiskott–Aldrich syndrome protein (WASp) and the ARP2/3 complex. WASp−/− mouse blood displays impaired platelet aggregate formation at arteriolar shear rates. We propose actin nodules are platelet podosome-related structures required for platelet–platelet interaction and their absence contributes to the bleeding diathesis of Wiskott–Aldrich syndrome. During early platelet spreading a novel F-actin structure forms, called the actin nodule. Here Poulter et al. demonstrate that actin nodule formation depends on WASp and the Arp2/3 complex, and using super-resolution microscopy they show that nodules bear a structural resemblance to podosomes.
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Affiliation(s)
- Natalie S Poulter
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Alice Y Pollitt
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Amy Davies
- PSIBS doctoral training centre, School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Dessislava Malinova
- Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Gerard B Nash
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Mike J Hannon
- PSIBS doctoral training centre, School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Zoe Pikramenou
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Joshua Z Rappoport
- The Center for Advanced Microscopy and Nikon Imaging Center, Morton 2-681, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, Illinois 60611, USA
| | - John H Hartwig
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Dylan M Owen
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Adrian J Thrasher
- Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Stephen P Watson
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Steven G Thomas
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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21
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The sweeter aspects of platelet activation: A lectin-based assay reveals agonist-specific glycosylation patterns. Biochim Biophys Acta Gen Subj 2014; 1840:3423-33. [PMID: 25175560 DOI: 10.1016/j.bbagen.2014.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 08/17/2014] [Accepted: 08/21/2014] [Indexed: 01/28/2023]
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22
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Abstract
Src family kinases (SFKs) play a central role in mediating the rapid response of platelets to vascular injury. They transmit activation signals from a diverse repertoire of platelet surface receptors, including the integrin αIIbβ3, the immunoreceptor tyrosine-based activation motif-containing collagen receptor complex GPVI-FcR γ-chain, and the von Willebrand factor receptor complex GPIb-IX-V, which are essential for thrombus growth and stability. Ligand-mediated clustering of these receptors triggers an increase in SFK activity and downstream tyrosine phosphorylation of enzymes, adaptors, and cytoskeletal proteins that collectively propagate the signal and coordinate platelet activation. A growing body of evidence has established that SFKs also contribute to Gq- and Gi-coupled receptor signaling that synergizes with primary activation signals to maximally activate platelets and render them prothrombotic. Interestingly, SFKs concomitantly activate inhibitory pathways that limit platelet activation and thrombus size. In this review, we discuss past discoveries that laid the foundation for this fundamental area of platelet signal transduction, recent progress in our understanding of the distinct and overlapping functions of SFKs in platelets, and new avenues of research into mechanisms of SFK regulation. We also highlight the thrombotic and hemostatic consequences of targeting platelet SFKs.
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23
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Abstract
α-Actinins are a major class of actin filament cross-linking proteins expressed in virtually all cells. In muscle, actinins cross-link thin filaments from adjacent sarcomeres. In non-muscle cells, different actinin isoforms play analogous roles in cross-linking actin filaments and anchoring them to structures such as cell-cell and cell-matrix junctions. Although actinins have long been known to play roles in cytokinesis, cell adhesion and cell migration, recent studies have provided further mechanistic insights into these functions. Roles for actinins in synaptic plasticity and membrane trafficking events have emerged more recently, as has a 'non-canonical' function for actinins in transcriptional regulation in the nucleus. In the present paper we review recent advances in our understanding of these diverse cell biological functions of actinins in non-muscle cells, as well as their roles in cancer and in genetic disorders affecting platelet and kidney physiology. We also make two proposals with regard to the actinin nomenclature. First, we argue that naming actinin isoforms according to their expression patterns is problematic and we suggest a more precise nomenclature system. Secondly, we suggest that the α in α-actinin is superfluous and can be omitted.
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24
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Khan A, Li D, Ibrahim S, Smyth E, Woulfe DS. The physical association of the P2Y12 receptor with PAR4 regulates arrestin-mediated Akt activation. Mol Pharmacol 2014; 86:1-11. [PMID: 24723492 DOI: 10.1124/mol.114.091595] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is now well accepted that protease activated receptor (PAR) 1 and PAR4 have differential roles in platelet activation. PAR4, a low-affinity thrombin receptor in human platelets, participates in sustained platelet activation in a P2Y12-dependent manner; however, the mechanisms are not defined. Our previous studies demonstrated that thrombin induces the association of PAR4 with P2Y12, together with arrestin recruitment to the complex. Here we show that PAR4 and P2Y12 directly interact to coregulate Akt signaling after PAR4 activation. We observed direct and specific interaction of P2Y12 with PAR4 but not PAR1 by bioluminescent resonance energy transfer when the receptors were coexpressed in human embryonic kidney 293T cells. PAR4-P2Y12 dimerization was promoted by PAR4-AP and inhibited by P2Y12 antagonist. By using sequence comparison of the transmembrane domains of PAR1 and PAR4, we designed a mutant form of PAR4, "PAR4SFT," by replacing LGL194-196 at the base of transmembrane domain 4 with the corresponding aligned PAR1 residues SFT 220-222. PAR4SFT supported only 8.74% of PAR4-P2Y12 interaction, abolishing P2Y12-dependent arrestin recruitment to PAR4 and Akt activation. Nonetheless, PAR4SFT still supported homodimerization with PAR4. PAR4SFT failed to induce a calcium flux when expressed independently; however, coexpression of increasing concentrations of PAR4SFT, together with PAR4 potentiated PAR4-mediated calcium flux, suggested that PAR4 act as homodimers to signal to Gq-coupled calcium responses. In conclusion, PAR4 LGL (194-196) governs agonist-dependent association of PAR4 with P2Y12 and contributes to Gq-coupled calcium responses. PAR4-P2Y12 association supports arrestin-mediated sustained signaling to Akt. Hence, PAR4-P2Y12 dimerization is likely to be important for the PAR4-P2Y12 dependent stabilization of platelet thrombi.
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Affiliation(s)
- Aasma Khan
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
| | - Dongjun Li
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
| | - Salam Ibrahim
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
| | - Emer Smyth
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
| | - Donna S Woulfe
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
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25
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Terada C, Mori J, Okazaki H, Satake M, Tadokoro K. Effects of riboflavin and ultraviolet light treatment on platelet thrombus formation on collagen via integrin αIIbβ3 activation. Transfusion 2014; 54:1808-16. [DOI: 10.1111/trf.12566] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 11/29/2013] [Accepted: 12/02/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Chikahiro Terada
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
| | - Junpei Mori
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
| | - Hitoshi Okazaki
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
| | - Masahiro Satake
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
| | - Kenji Tadokoro
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
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26
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Abstract
Integrins are heterodimeric cell surface adhesion receptors essential for multicellular life. They connect cells to the extracellular environment and transduce chemical and mechanical signals to and from the cell. Intracellular proteins that bind the integrin cytoplasmic tail regulate integrin engagement of extracellular ligands as well as integrin localization and trafficking. Cytoplasmic integrin-binding proteins also function downstream of integrins, mediating links to the cytoskeleton and to signaling cascades that impact cell motility, growth, and survival. Here, we review key integrin-interacting proteins and their roles in regulating integrin activity, localization, and signaling.
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Affiliation(s)
- Elizabeth M Morse
- Department of Cell Biology and ‡Department of Pharmacology, Yale University School of Medicine , 333 Cedar Street, New Haven, Connecticut 06520, United States
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27
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Jahed Z, Shams H, Mehrbod M, Mofrad MRK. Mechanotransduction pathways linking the extracellular matrix to the nucleus. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 310:171-220. [PMID: 24725427 DOI: 10.1016/b978-0-12-800180-6.00005-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cells contain several mechanosensing components that transduce mechanical signals into biochemical cascades. During cell-ECM adhesion, a complex network of molecules mechanically couples the extracellular matrix (ECM), cytoskeleton, and nucleoskeleton. The network comprises transmembrane receptor proteins and focal adhesions, which link the ECM and cytoskeleton. Additionally, recently identified protein complexes extend this linkage to the nucleus by linking the cytoskeleton and the nucleoskeleton. Despite numerous studies in this field, due to the complexity of this network, our knowledge of the mechanisms of cell-ECM adhesion at the molecular level remains remarkably incomplete. Herein, we present a review of the structures of key molecules involved in cell-ECM adhesion, along with an evaluation of their predicted roles in mechanical sensing. Additionally, specific binding events prompted by force-induced conformational changes of each molecule are discussed. Finally, we propose a model for the biomechanical events prominent in cell-ECM adhesion.
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Affiliation(s)
- Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Hengameh Shams
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Mehrdad Mehrbod
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA.
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28
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Senis YA. Protein-tyrosine phosphatases: a new frontier in platelet signal transduction. J Thromb Haemost 2013; 11:1800-13. [PMID: 24015866 DOI: 10.1111/jth.12359] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Indexed: 08/31/2023]
Abstract
Platelet activation must be tightly controlled in order to allow platelets to respond rapidly to vascular injury and prevent thrombosis from occurring. Protein-tyrosine phosphorylation is one of the main ways in which activation signals are transmitted in platelets. Although much is known about the protein-tyrosine kinases (PTKs) that initiate and propagate activation signals, relatively little is known about the protein-tyrosine phosphatases (PTPs) that modulate these signals in platelets. PTPs are a family of enzymes that dephosphorylate tyrosine residues in proteins and regulate signals transmitted within cells. PTPs have been implicated in a variety of pathological conditions, including cancer, diabetes and autoimmunity, but their functions in hemostasis and thrombosis remain largely undefined. Exciting new findings from a number of groups have revealed that PTPs are in fact critical regulators of platelet activation and thrombosis. The primary aim of this review is to highlight the unique and important functions of PTPs in regulating platelet activity. Establishing the functions of PTPs in platelets is essential to better understand the molecular basis of thrombosis and may lead to the development of improved antithrombotic therapies.
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Affiliation(s)
- Y A Senis
- Centre for Cardiovascular and Respiratory Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
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29
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Subramani J, Ghosh M, Rahman MM, Caromile LA, Gerber C, Rezaul K, Han DK, Shapiro LH. Tyrosine phosphorylation of CD13 regulates inflammatory cell-cell adhesion and monocyte trafficking. THE JOURNAL OF IMMUNOLOGY 2013; 191:3905-12. [PMID: 23997214 DOI: 10.4049/jimmunol.1301348] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CD13 is a large cell surface peptidase expressed on the monocytes and activated endothelial cells that is important for homing to and resolving the damaged tissue at sites of injury. We showed previously that cross-linking of human monocytic CD13 with activating Abs induces strong adhesion to endothelial cells in a tyrosine kinase- and microtubule-dependent manner. In the current study, we examined the molecular mechanisms underlying these observations in vitro and in vivo. We found that cross-linking of CD13 on U937 monocytic cells induced phosphorylation of a number of proteins, including Src, FAK, and ERK, and inhibition of these abrogated CD13-dependent adhesion. We found that CD13 itself was phosphorylated in a Src-dependent manner, which was an unexpected finding because its 7-aa cytoplasmic tail was assumed to be inert. Furthermore, CD13 was constitutively associated with the scaffolding protein IQGAP1, and CD13 cross-linking induced complex formation with the actin-binding protein α-actinin, linking membrane-bound CD13 to the cytoskeleton, further supporting CD13 as an inflammatory adhesion molecule. Mechanistically, mutation of the conserved CD13 cytoplasmic tyrosine to phenylalanine abrogated adhesion; Src, FAK, and ERK phosphorylation; and cytoskeletal alterations upon Ab cross-linking. Finally, CD13 was phosphorylated in isolated murine inflammatory peritoneal exudate cells, and adoptive transfer of monocytic cell lines engineered to express the mutant CD13 were severely impaired in their ability to migrate into the inflamed peritoneum, confirming that CD13 phosphorylation is relevant to inflammatory cell trafficking in vivo. Therefore, this study identifies CD13 as a novel, direct activator of intracellular signaling pathways in pathophysiological conditions.
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Affiliation(s)
- Jaganathan Subramani
- Center for Vascular Biology, University of Connecticut Health Center, Farmington, CT 06030
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30
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Holly SP, Chang JW, Li W, Niessen S, Phillips RM, Piatt R, Black JL, Smith MC, Boulaftali Y, Weyrich AS, Bergmeier W, Cravatt BF, Parise LV. Chemoproteomic discovery of AADACL1 as a regulator of human platelet activation. ACTA ACUST UNITED AC 2013; 20:1125-34. [PMID: 23993462 DOI: 10.1016/j.chembiol.2013.07.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/19/2013] [Accepted: 07/23/2013] [Indexed: 12/27/2022]
Abstract
A comprehensive knowledge of the platelet proteome is necessary for understanding thrombosis and for envisioning antiplatelet therapies. To discover other biochemical pathways in human platelets, we screened platelets with a carbamate library designed to interrogate the serine hydrolase subproteome and used competitive activity-based protein profiling to map the targets of active carbamates. We identified an inhibitor that targets arylacetamide deacetylase-like 1 (AADACL1), a lipid deacetylase originally identified in invasive cancers. Using this compound, along with highly selective second-generation inhibitors of AADACL1, metabolomics, and RNA interference, we show that AADACL1 regulates platelet aggregation, thrombus growth, RAP1 and PKC activation, lipid metabolism, and fibrinogen binding to platelets and megakaryocytes. These data provide evidence that AADACL1 regulates platelet and megakaryocyte activation and highlight the value of this chemoproteomic strategy for target discovery in platelets.
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Affiliation(s)
- Stephen P Holly
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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31
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Calderwood DA, Campbell ID, Critchley DR. Talins and kindlins: partners in integrin-mediated adhesion. Nat Rev Mol Cell Biol 2013; 14:503-17. [PMID: 23860236 PMCID: PMC4116690 DOI: 10.1038/nrm3624] [Citation(s) in RCA: 420] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Integrin receptors provide a dynamic, tightly-regulated link between the extracellular matrix (or cellular counter-receptors) and intracellular cytoskeletal and signalling networks, enabling cells to sense and respond to their chemical and physical environment. Talins and kindlins, two families of FERM-domain proteins, bind the cytoplasmic tail of integrins, recruit cytoskeletal and signalling proteins involved in mechanotransduction and synergize to activate integrin binding to extracellular ligands. New data reveal the domain structure of full-length talin, provide insights into talin-mediated integrin activation and show that RIAM recruits talin to the plasma membrane, whereas vinculin stabilizes talin in cell-matrix junctions. How kindlins act is less well-defined, but disease-causing mutations show that kindlins are also essential for integrin activation, adhesion, cell spreading and signalling.
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Affiliation(s)
- David A Calderwood
- Departments of Pharmacology and of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Iain D Campbell
- Department of Biochemistry, University of Oxford, S. Parks Rd., Oxford, OX1 3QU, UK
| | - David R Critchley
- Department of Biochemistry, University of Leicester, Leicester LE1 7RH
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Das M, Ithychanda S, Qin J, Plow EF. Mechanisms of talin-dependent integrin signaling and crosstalk. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:579-88. [PMID: 23891718 DOI: 10.1016/j.bbamem.2013.07.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 07/03/2013] [Accepted: 07/15/2013] [Indexed: 01/01/2023]
Abstract
Cells undergo dynamic remodeling of the cytoskeleton during adhesion and migration on various extracellular matrix (ECM) substrates in response to physiological and pathological cues. The major mediators of such cellular responses are the heterodimeric adhesion receptors, the integrins. Extracellular or intracellular signals emanating from different signaling cascades cause inside-out signaling of integrins via talin, a cystokeletal protein that links integrins to the actin cytoskeleton. Various integrin subfamilies communicate with each other and growth factor receptors under diverse cellular contexts to facilitate or inhibit various integrin-mediated functions. Since talin is an essential mediator of integrin activation, much of the integrin crosstalk would therefore be influenced by talin. However, despite the existence of an extensive body of knowledge on the role of talin in integrin activation and as a stabilizer of ECM-actin linkage, information on its role in regulating inter-integrin communication is limited. This review will focus on the structure of talin, its regulation of integrin activation and discuss its potential role in integrin crosstalk. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Mitali Das
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Lerner Research Institute, Cleveland Clinic
| | - Sujay Ithychanda
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Lerner Research Institute, Cleveland Clinic
| | - Jun Qin
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Lerner Research Institute, Cleveland Clinic
| | - Edward F Plow
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Lerner Research Institute, Cleveland Clinic
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Pecci A. Pathogenesis and management of inherited thrombocytopenias: rationale for the use of thrombopoietin-receptor agonists. Int J Hematol 2013; 98:34-47. [PMID: 23636669 DOI: 10.1007/s12185-013-1351-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 12/30/2022]
Abstract
Knowledge in the field of inherited thrombocytopenias (ITs) has considerably improved over the recent years. In the last 5 years, nine new genes whose mutations are responsible for thrombocytopenia have been identified, and this also led to the recognition of several novel nosographic entities, such as thrombocytopenias deriving from mutations in CYCS, TUBB1, FLNA, ITGA2B/ITGB3, ANKRD26 and ACTN1. The identification of novel molecular alterations causing thrombocytopenia together with improvement of methodologies to study megakaryopoiesis led to considerable advances in understanding pathophysiology of ITs, thus providing the background for proposing new treatments. Thrombopoietin-receptor agonists (TPO-RAs) represent an appealing therapeutic hypothesis for ITs and have been tested in a limited number of patients. In this review, we provide an updated description of pathogenetic mechanisms of thrombocytopenia in the different forms of ITs and recapitulate the current management of these disorders. Moreover, we report the available clinical and preclinical data about the role of TPO-RAs in ITs and discuss the rationale for the use of these molecules in view of pathogenesis of the different forms of thrombocytopenia of genetic origin.
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Affiliation(s)
- Alessandro Pecci
- Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation, University of Pavia, Piazzale Golgi, 27100 Pavia, Italy.
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Kunishima S, Okuno Y, Yoshida K, Shiraishi Y, Sanada M, Muramatsu H, Chiba K, Tanaka H, Miyazaki K, Sakai M, Ohtake M, Kobayashi R, Iguchi A, Niimi G, Otsu M, Takahashi Y, Miyano S, Saito H, Kojima S, Ogawa S. ACTN1 mutations cause congenital macrothrombocytopenia. Am J Hum Genet 2013; 92:431-8. [PMID: 23434115 DOI: 10.1016/j.ajhg.2013.01.015] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 12/20/2012] [Accepted: 01/23/2013] [Indexed: 11/30/2022] Open
Abstract
Congenital macrothrombocytopenia (CMTP) is a heterogeneous group of rare platelet disorders characterized by a congenital reduction of platelet counts and abnormally large platelets, for which CMTP-causing mutations are only found in approximately half the cases. We herein performed whole-exome sequencing and targeted Sanger sequencing to identify mutations that cause CMTP, in which a dominant mode of transmission had been suspected but for which no known responsible mutations have been documented. In 13 Japanese CMTP-affected pedigrees, we identified six (46%) affected by ACTN1 variants cosegregating with CMTP. In the entire cohort, ACNT1 variants accounted for 5.5% of the dominant forms of CMTP cases and represented the fourth most common cause in Japanese individuals. Individuals with ACTN1 variants presented with moderate macrothrombocytopenia with anisocytosis but were either asymptomatic or had only a modest bleeding tendency. ACTN1 encodes α-actinin-1, a member of the actin-crosslinking protein superfamily that participates in the organization of the cytoskeleton. In vitro transfection experiments in Chinese hamster ovary cells demonstrated that altered α-actinin-1 disrupted the normal actin-based cytoskeletal structure. Moreover, transduction of mouse fetal liver-derived megakaryocytes with disease-associated ACTN1 variants caused a disorganized actin-based cytoskeleton in megakaryocytes, resulting in the production of abnormally large proplatelet tips, which were reduced in number. Our findings provide an insight into the pathogenesis of CMTP.
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Affiliation(s)
- Shinji Kunishima
- Department of Advanced Diagnosis, Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya, Japan.
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Dysfunction of the PI3 kinase/Rap1/integrin α(IIb)β(3) pathway underlies ex vivo platelet hypoactivity in essential thrombocythemia. Blood 2012; 121:1209-19. [PMID: 23243278 DOI: 10.1182/blood-2012-05-431288] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Patients with myeloproliferative disorders (MPDs), such as essential thrombocythemia (ET) have increased risk of thrombosis and bleeding, which are major sources of morbidity and mortality. Most MPD patients have a gain of function mutation in Janus kinase 2 (JAK2V617F), but little is known how JAK2V617F affects platelet function. Here, we demonstrate that platelets from ET patients have impaired SFLLRN-mediated fibrinogen binding and have lost the potentiating effect of thrombopoietin (which couples to JAK2) on this pathway. In contrast, SFLLRN-mediated P-selectin expression, ATP secretion, phosphorylation of the PKC substrate pleckstrin, and Ca(2+) mobilization were unaffected in JAK2V617F positive platelets. In addition, thrombopoietin-mediated JAK2 phosphorylation was unchanged, suggesting that signaling pathways activated downstream of JAK2 are impaired. Indeed, we found that platelets from JAK2V617F positive ET patients have significantly reduced phosphorylation of the PI3 kinase substrate Akt, and have reduced activation of Rap1 in response to thrombopoietin, IGF-1,ADP, SFLLRN, and thrombin. This effect was independent of Giα P2Y12 purinergic receptor function as ADP-mediated inhibition of VASP phosphorylation was unchanged. These results demonstrate that the PI3 kinase/Rap1 pathway is intrinsically impaired in platelets from JAK2V617F-positive ET patients, resulting in diminished thrombin and thrombopoietin-mediated integrin α(IIb)β(3) activation.
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Nakazawa T, Tadokoro S, Kamae T, Kiyomizu K, Kashiwagi H, Honda S, Kanakura Y, Tomiyama Y. Agonist stimulation, talin-1, and kindlin-3 are crucial for α(IIb)β(3) activation in a human megakaryoblastic cell line, CMK. Exp Hematol 2012; 41:79-90.e1. [PMID: 23022222 DOI: 10.1016/j.exphem.2012.09.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 09/20/2012] [Accepted: 09/24/2012] [Indexed: 10/27/2022]
Abstract
Platelet integrin α(IIb)β(3) activation is regulated by inside-out signaling via agonist stimulation. However, when α(IIb)β(3) was exogenously expressed in cell lines such as Chinese hamster ovarian cells, physiological agonists hardly induced α(IIb)β(3) activation. To overcome this disadvantage, we characterized the functional regulation of endogenously expressed α(IIb)β(3) in a megakaryoblastic cell line, CMK, employing an initial velocity assay for PAC-1 binding. We firstly demonstrated that protease-activated receptor 1-activating peptide induced robust, but transient α(IIb)β(3) activation in CMK cells with high glycoprotein-Ib expression. Stable talin-1 or kindlin-3 knockdown cells confirmed that the protease-activated receptor 1-activating peptide-induced α(IIb)β(3) activation was dependent on talin-1 and kindlin-3 expression. In sharp contrast to exogenously expressed α(IIb)β(3) in Chinese hamster ovarian cells, transient overexpression of full-length talin (FL-talin) or talin-head domain (THD) alone did not activate α(IIb)β(3) in CMK cells, but required agonist stimulation. Similarly, kindlin-3 overexpression alone did not induce α(IIb)β(3) activation, but it significantly augmented agonist-induced α(IIb)β(3) activation. Several mutants of FL-talin and THD suggested that the head-rod interaction was critical for autoinhibition of talin-1, and the interaction between the THD and the membrane-proximal region of the β(3) cytoplasmic tail was essential for talin-mediated α(IIb)β(3) activation. In addition, THD and kindlin-3 cooperatively augmented protease-activated receptor 1-induced α(IIb)β(3) activation. We proposed that the CMK cell line is an attractive platform for investigating agonist-, talin-1-, and kindlin-3- dependent α(IIb)β(3) activation.
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Affiliation(s)
- Tsuyoshi Nakazawa
- Department of Hematology and Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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Kamae T, Kiyomizu K, Nakazawa T, Tadokoro S, Kashiwagi H, Honda S, Kanakura Y, Tomiyama Y. Bleeding tendency and impaired platelet function in a patient carrying a heterozygous mutation in the thromboxane A2 receptor. J Thromb Haemost 2011; 9:1040-8. [PMID: 21342433 DOI: 10.1111/j.1538-7836.2011.04245.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Thromboxane A(2) receptor (TXA(2)R) abnormality appears to dominantly disturb platelet function. OBJECTIVES To reveal a molecular genetic defect in a patient with TXA(2)R abnormality and investigate the mechanism for the impaired response to TXA(2). PATIENT The proband (OSP-2, PT) was a 7-year-old Japanese girl, suffering from repeated mucocutaneous bleeding. METHODS AND RESULTS U46619 (2.5 and 10 μm)-induced platelet aggregation was remarkably impaired in the proband and her father. Immunoblots showed that TXA(2)R expression levels in their platelets were approximately 50% of controls, and nucleotide sequence analysis revealed that they were heterozygous for a novel mutation, c.167dupG in the TXA(2)R cDNA. Expression studies using Chinese hamster ovary (CHO) cells indicated that the mutation is responsible for the expression defect in TXA(2)R. We then examined α(IIb)β(3) activation by employing an initial velocity analysis and revealed that U46619 failed to induce a sustained α(IIb)β(3) and Rap1B activation in the proband. In addition, platelet secretion as monitored by P-selectin expression was markedly impaired in response to U46619 but not to ADP. The interaction between secreted ADP and P2Y(12) has been shown to play a critical role in the sustained α(IIb)β(3) activation (Kamae et al. J Thromb Haemost 2006; 4: 1379). As expected, small amounts of exogenous ADP (0.5 μm) partially restored the sustained α(IIb)β(3) activation induced by U46619. CONCLUSION Our present data strongly suggest that the impaired platelet activation in response to U46619 in the heterozygous subject for the TXA(2)R mutation is, at least in part, as a result of the decrease in ADP secretion.
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Affiliation(s)
- T Kamae
- Department of Hematology and Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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