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Salz A, Gurniak C, Jönsson F, Witke W. Cofilin1-driven actin dynamics controls migration of thymocytes and is essential for positive selection in the thymus. J Cell Sci 2020; 133:jcs238048. [PMID: 31974112 DOI: 10.1242/jcs.238048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 01/14/2020] [Indexed: 11/20/2022] Open
Abstract
Actin dynamics is essential for T-cell development. We show here that cofilin1 is the key molecule for controlling actin filament turnover in this process. Mice with specific depletion of cofilin1 in thymocytes showed increased steady-state levels of actin filaments, and associated alterations in the pattern of thymocyte migration and adhesion. Our data suggest that cofilin1 is controlling oscillatory F-actin changes, a parameter that influences the migration pattern in a 3-D environment. In a collagen matrix, cofilin1 controls the speed and resting intervals of migrating thymocytes. Cofilin1 was not involved in thymocyte proliferation, cell survival, apoptosis or surface receptor trafficking. However, in cofilin1 mutant mice, impaired adhesion and migration resulted in a specific block of thymocyte differentiation from CD4/CD8 double-positive thymocytes towards CD4 and CD8 single-positive cells. Our data suggest that tuning of the dwelling time of thymocytes in the thymic niches is tightly controlled by cofilin1 and essential for positive selection during T-cell differentiation. We describe a novel role of cofilin1 in the physiological context of migration-dependent cell differentiation.
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Affiliation(s)
- Andree Salz
- Institute of Genetics, University of Bonn, Karlrobert-Kreiten Strasse 13, 53115 Bonn, Germany
| | - Christine Gurniak
- Institute of Genetics, University of Bonn, Karlrobert-Kreiten Strasse 13, 53115 Bonn, Germany
| | - Friederike Jönsson
- Unit of Antibodies in Therapy and Pathology, Institut Pasteur, UMR 1222 INSERM, 75015 Paris, France
| | - Walter Witke
- Institute of Genetics, University of Bonn, Karlrobert-Kreiten Strasse 13, 53115 Bonn, Germany
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2
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Intermittent rolling is a defect of the extravasation cascade caused by Myosin1e-deficiency in neutrophils. Proc Natl Acad Sci U S A 2019; 116:26752-26758. [PMID: 31811025 DOI: 10.1073/pnas.1902502116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Neutrophil extravasation is a migratory event in response to inflammation that depends on cytoskeletal dynamics regulated by myosins. Myosin-1e (Myo1e) is a long-tailed class-I myosin that has not yet been studied in the context of neutrophil-endothelial interactions and neutrophil extravasation. Intravital microscopy of TNFα-inflamed cremaster muscles in Myo1e-deficient mice revealed that Myo1e is required for efficient neutrophil extravasation. Specifically, Myo1e deficiency caused increased rolling velocity, decreased firm adhesion, aberrant crawling, and strongly reduced transmigration. Interestingly, we observed a striking discontinuous rolling behavior termed "intermittent rolling," during which Myo1e-deficient neutrophils showed alternating rolling and jumping movements. Surprisingly, chimeric mice revealed that these effects were due to Myo1e deficiency in leukocytes. Vascular permeability was not significantly altered in Myo1e KO mice. Myo1e-deficient neutrophils showed diminished arrest, spreading, uropod formation, and chemotaxis due to defective actin polymerization and integrin activation. In conclusion, Myo1e critically regulates adhesive interactions of neutrophils with the vascular endothelium and neutrophil extravasation. Myo1e may therefore be an interesting target in chronic inflammatory diseases characterized by excessive neutrophil recruitment.
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An J, Yin JJ, He Y, Sui RX, Miao Q, Wang Q, Yu JZ, Yu JW, Shi FD, Ma CG, Xiao BG. Temporal and Spatial Dynamics of Astroglial Reaction and Immune Response in Cuprizone-Induced Demyelination. Neurotox Res 2019; 37:587-601. [DOI: 10.1007/s12640-019-00129-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/03/2019] [Accepted: 10/25/2019] [Indexed: 12/14/2022]
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Wurzer H, Hoffmann C, Al Absi A, Thomas C. Actin Cytoskeleton Straddling the Immunological Synapse between Cytotoxic Lymphocytes and Cancer Cells. Cells 2019; 8:cells8050463. [PMID: 31100864 PMCID: PMC6563383 DOI: 10.3390/cells8050463] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 02/06/2023] Open
Abstract
The immune system is a fundamental part of the tumor microenvironment. In particular, cytotoxic lymphocytes, such as cytolytic T cells and natural killer cells, control tumor growth and disease progression by interacting and eliminating tumor cells. The actin cytoskeleton of cytotoxic lymphocytes engaged in an immunological synapse has received considerable research attention. It has been recognized as a central mediator of the formation and maturation of the immunological synapse, and its signaling and cytolytic activities. In comparison, fewer studies have explored the organization and function of actin filaments on the target cancer cell side of the immunological synapse. However, there is growing evidence that the actin cytoskeleton of cancer cells also undergoes extensive remodeling upon cytotoxic lymphocyte attack, and that such remodeling can alter physical and functional interactions at the immunological synapse. In this article, we review the current knowledge of actin organization and functions at both sides of the immunological synapse between cytotoxic lymphocytes and cancer cells, with particular focus on synapse formation, signaling and cytolytic activity, and immune evasion.
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Affiliation(s)
- Hannah Wurzer
- Cytoskeleton and Cancer Progression; Laboratory of Experimental Cancer Research, Department of Oncology 84 Val Fleuri, L-1526 Luxembourg City, Luxembourg.
- University of Luxembourg, Faculty of Science, Technology and Communication, 2 Avenue de l'Université, L-4365 Esch-sur-Alzette, Luxembourg.
| | - Céline Hoffmann
- Cytoskeleton and Cancer Progression; Laboratory of Experimental Cancer Research, Department of Oncology 84 Val Fleuri, L-1526 Luxembourg City, Luxembourg.
| | - Antoun Al Absi
- Cytoskeleton and Cancer Progression; Laboratory of Experimental Cancer Research, Department of Oncology 84 Val Fleuri, L-1526 Luxembourg City, Luxembourg.
- University of Strasbourg, 67081 Strasbourg, France.
| | - Clément Thomas
- Cytoskeleton and Cancer Progression; Laboratory of Experimental Cancer Research, Department of Oncology 84 Val Fleuri, L-1526 Luxembourg City, Luxembourg.
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Harrison DL, Fang Y, Huang J. T-Cell Mechanobiology: Force Sensation, Potentiation, and Translation. FRONTIERS IN PHYSICS 2019; 7:45. [PMID: 32601597 PMCID: PMC7323161 DOI: 10.3389/fphy.2019.00045] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A T cell is a sensitive self-referential mechanical sensor. Mechanical forces influence the recognition, activation, differentiation, and function throughout the lifetime of a T cell. T cells constantly perceive and respond to physical stimuli through their surface receptors, cytoskeleton, and subcellular structures. Surface receptors receive physical cues in the form of forces generated through receptor-ligand binding events, which are dynamically regulated by contact tension, shear stress, and substrate rigidity. The resulting mechanotransduction not only influences T-cell recognition and signaling but also possibly modulates cell metabolism and gene expression. Moreover, forces also dynamically regulate the deformation, organization, and translocation of cytoskeleton and subcellular structures, leading to changes in T-cell mobility, migration, and infiltration. However, the roles and mechanisms of how mechanical forces modulate T-cell recognition, signaling, metabolism, and gene expression, are largely unknown and underappreciated. Here, we review recent technological and scientific advances in T-cell mechanobiology, discuss possible roles and mechanisms of T-cell mechanotransduction, and propose new research directions of this emerging field in health and disease.
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Affiliation(s)
- Devin L. Harrison
- The Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, IL, United States
| | - Yun Fang
- The Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, IL, United States
- Section of Pulmonary and Critical Care, Department of Medicine, The University of Chicago, Chicago, IL, United States
| | - Jun Huang
- The Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, IL, United States
- Institute for Molecular Engineering, The University of Chicago, Chicago, IL, United States
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6
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Mechanics of antigen extraction in the B cell synapse. Mol Immunol 2018; 101:319-328. [PMID: 30036798 DOI: 10.1016/j.molimm.2018.07.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/11/2018] [Indexed: 12/16/2022]
Abstract
B cell encounter with antigen displayed on antigen-presenting cells leads to B cell immune synapse formation, internalisation of the antigen, and stimulation of antibody responses. The sensitivity with which B cells detect antigen, and the quality and quantity of antigen that B cells acquire, depend upon mechanical properties of the immune synapse including interfacial tension, the strength of intermolecular bonds, and the compliance of the molecules and membranes that participate in antigen presentation. In this review, we discuss our current understanding of how these various physical parameters influence B cell antigen extraction in the immune synapse and how a more comprehensive understanding of B cell mechanics may promote the development of new approaches to stimulate the production of desired antibodies.
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Jo S, Kim HR, Mun Y, Jun CD. Transgelin-2 in immunity: Its implication in cell therapy. J Leukoc Biol 2018; 104:903-910. [PMID: 29749649 DOI: 10.1002/jlb.mr1117-470r] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 04/02/2018] [Accepted: 04/03/2018] [Indexed: 12/31/2022] Open
Abstract
Transgelin-2 is a small 22-kDa actin-binding protein implicated in actin dynamics, which stabilizes actin structures and participates in actin-associated signaling pathways. Much curiosity regarding transgelin-2 has centered around its dysregulation in tumor development and associated diseases. However, recent studies have shed new light on the functions of transgelin-2, the only transgelin family member present in leukocytes, in the context of various immune responses. In this review, we outlined the biochemical properties of transgelin-2 and its physiological functions in T cells, B cells, and macrophages. Transgelin-2 regulates T cell activation by stabilizing the actin cytoskeleton at the immunological synapse. Transgelin-2 in B cells also participates in the stabilization of T cell-B cell conjugates. While transgelin-2 is expressed at trace levels in macrophages, its expression is highly upregulated upon lipopolysaccharide stimulation and plays an essential role in macrophage phagocytosis. Since transgelin-2 increases T cell adhesion to target cells via boosting the "inside-out" costimulatory activation of leukocyte function-associated antigen 1, transgelin-2 could be a suitable candidate to potentiate the antitumor response of cytotoxic T cells by compensating for the lack of costimulation in tumor microenvironment. We discussed the feasibility of using native or engineered transgelin-2 as a synergistic molecule in cell-based immunotherapies, without inducing off-target disturbance in actin dynamics in other cells.
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Affiliation(s)
- Suin Jo
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Hye-Ran Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - YeVin Mun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Chang-Duk Jun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
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8
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Meissner JM, Sikorski AF, Nawara T, Grzesiak J, Marycz K, Bogusławska DM, Michalczyk I, Lecomte MC, Machnicka B. αII-spectrin in T cells is involved in the regulation of cell-cell contact leading to immunological synapse formation? PLoS One 2017; 12:e0189545. [PMID: 29244882 PMCID: PMC5731749 DOI: 10.1371/journal.pone.0189545] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/27/2017] [Indexed: 01/08/2023] Open
Abstract
T-lymphocyte activation after antigen presentation to the T-Cell Receptor (TCR) is a critical step in the development of proper immune responses to infection and inflammation. This dynamic process involves reorganization of the actin cytoskeleton and signaling molecules at the cell membrane, leading to the formation of the Immunological Synapse (IS). The mechanisms regulating the formation of the IS are not completely understood. Nonerythroid spectrin is a membrane skeletal protein involved in the regulation of many cellular processes, including cell adhesion, signaling and actin cytoskeleton remodeling. However, the role of spectrin in IS formation has not been explored. We used molecular, imaging and cellular approaches to show that nonerythroid αII-spectrin redistributes to the IS during T-cell activation. The redistribution of spectrin coincides with the relocation of CD45 and LFA-1, two components essential for IS formation and stability. We assessed the role of spectrin by shRNA-mediated depletion from Jurkat T cells and show that spectrin-depleted cells exhibit decreased adhesion and are defective in forming lamellipodia and filopodia. Importantly, IS formation is impaired in spectrin-depleted cells. Thus, spectrin may be engaged in regulation of distinct events necessary for the establishment and maturity of the IS: besides the involvement of spectrin in the control of CD45 and LFA-1 surface display, spectrin acts in the establishment of cell-cell contact and adhesion processes during the formation of the IS.
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Affiliation(s)
- Justyna M. Meissner
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wrocław, Poland
- Electron Microscopy Laboratory, Faculty of Biology, University of Environmental and Life Sciences Wrocław, Wrocław, Poland
| | - Aleksander F. Sikorski
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wrocław, Poland
| | - Tomasz Nawara
- Electron Microscopy Laboratory, Faculty of Biology, University of Environmental and Life Sciences Wrocław, Wrocław, Poland
| | - Jakub Grzesiak
- Electron Microscopy Laboratory, Faculty of Biology, University of Environmental and Life Sciences Wrocław, Wrocław, Poland
| | - Krzysztof Marycz
- Electron Microscopy Laboratory, Faculty of Biology, University of Environmental and Life Sciences Wrocław, Wrocław, Poland
| | | | - Izabela Michalczyk
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wrocław, Poland
| | - Marie-Christine Lecomte
- Biologie Intégrée du Globule Rouge UMR_S1134, Inserm, Univ. Paris Diderot, Sorbonne Paris Cité, Univ. de la Réunion, Univ. des Antilles, Paris, France
| | - Beata Machnicka
- Faculty of Biological Sciences, University of Zielona Góra, Zielona Góra, Poland
- * E-mail:
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9
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Borger JG, Morrison VL, Filby A, Garcia C, Uotila LM, Simbari F, Fagerholm SC, Zamoyska R. Caveolin-1 Influences LFA-1 Redistribution upon TCR Stimulation in CD8 T Cells. THE JOURNAL OF IMMUNOLOGY 2017. [PMID: 28637901 PMCID: PMC5523581 DOI: 10.4049/jimmunol.1700431] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
TCR stimulation by peptide-MHC complexes on APCs requires precise reorganization of molecules into the area of cellular contact to form an immunological synapse from where T cell signaling is initiated. Caveolin (Cav)1, a widely expressed transmembrane protein, is involved in the regulation of membrane composition, cellular polarity and trafficking, and the organization of signal transduction pathways. The presence of Cav1 protein in T cells was identified only recently, and its function in this context is not well understood. We show that Cav1-knockout CD8 T cells have a reduction in membrane cholesterol and sphingomyelin, and upon TCR triggering they exhibit altered morphology and polarity, with reduced effector function compared with Cav1 wild-type CD8 T cells. In particular, redistribution of the β2 integrin LFA-1 to the immunological synapse is compromised in Cav1-knockout T cells, as is the ability of LFA-1 to form high-avidity interactions with ICAM-1. Our results identify a role for Cav1 in membrane organization and β2 integrin function in primary CD8 T cells.
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Affiliation(s)
- Jessica G Borger
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | | | - Andrew Filby
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom; and
| | - Celine Garcia
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Liisa M Uotila
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Fabio Simbari
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | | | - Rose Zamoyska
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom;
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10
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Walther CG, Whitfield R, James DC. Importance of Interaction between Integrin and Actin Cytoskeleton in Suspension Adaptation of CHO cells. Appl Biochem Biotechnol 2015; 178:1286-302. [PMID: 26679704 PMCID: PMC4858566 DOI: 10.1007/s12010-015-1945-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 11/30/2015] [Indexed: 12/23/2022]
Abstract
The biopharmaceutical production process relies upon mammalian cell technology where single cells proliferate in suspension in a chemically defined synthetic environment. This environment lacks exogenous growth factors, usually contributing to proliferation of fibroblastic cell types such as Chinese hamster ovary (CHO) cells. Use of CHO cells for production hence requires a lengthy 'adaptation' process to select clones capable of proliferation as single cells in suspension. The underlying molecular changes permitting proliferation in suspension are not known. Comparison of the non-suspension-adapted clone CHO-AD and a suspension-adapted propriety cell line CHO-SA by flow cytometric analysis revealed a highly variable bi-modal expression pattern for cell-to-cell contact proteins in contrast to the expression pattern seen for integrins. Those have a uni-modal expression on suspension and adherent cells. Integrins showed a conformation distinguished by regularly distributed clusters forming a sphere on the cell membrane of suspension-adapted cells. Actin cytoskeleton analysis revealed reorganisation from the typical fibrillar morphology found in adherent cells to an enforced spherical subcortical actin sheath in suspension cells. The uni-modal expression and specific clustering of integrins could be confirmed for CHO-S, another suspension cell line. Cytochalasin D treatment resulted in breakdown of the actin sheath and the sphere-like integrin conformation demonstrating the link between integrins and actin in suspension-adapted CHO cells. The data demonstrates the importance of signalling changes, leading to an integrin rearrangement on the cell surface, and the necessity of the reinforcement of the actin cytoskeleton for proliferation in suspension conditions.
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Affiliation(s)
- Christa G Walther
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK.
- Chemical and Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK.
| | - Robert Whitfield
- Department of Applied Sciences and Health, Coventry University, James Starley Building, Coventry, CV1 5FB, UK
- Chemical and Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
| | - David C James
- Chemical and Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
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Na BR, Kim HR, Piragyte I, Oh HM, Kwon MS, Akber U, Lee HS, Park DS, Song WK, Park ZY, Im SH, Rho MC, Hyun YM, Kim M, Jun CD. TAGLN2 regulates T cell activation by stabilizing the actin cytoskeleton at the immunological synapse. ACTA ACUST UNITED AC 2015; 209:143-62. [PMID: 25869671 PMCID: PMC4395477 DOI: 10.1083/jcb.201407130] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
TAGLN2 stabilizes cortical F-actin and thereby maintains F-actin contents at the immunological synapse, which allows T cell activation following T cell receptor stimulation. The formation of an immunological synapse (IS) requires tight regulation of actin dynamics by many actin polymerizing/depolymerizing proteins. However, the significance of actin stabilization at the IS remains largely unknown. In this paper, we identify a novel function of TAGLN2—an actin-binding protein predominantly expressed in T cells—in stabilizing cortical F-actin, thereby maintaining F-actin contents at the IS and acquiring LFA-1 (leukocyte function-associated antigen-1) activation after T cell receptor stimulation. TAGLN2 blocks actin depolymerization and competes with cofilin both in vitro and in vivo. Knockout of TAGLN2 (TAGLN2−/−) reduced F-actin content and destabilized F-actin ring formation, resulting in decreased cell adhesion and spreading. TAGLN2−/− T cells displayed weakened cytokine production and cytotoxic effector function. These findings reveal a novel function of TAGLN2 in enhancing T cell responses by controlling actin stability at the IS.
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Affiliation(s)
- Bo-Ra Na
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Hye-Ran Kim
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Indre Piragyte
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Hyun-Mee Oh
- Bioindustrial Process Research Center, Korea Research Institute Bioscience and Biotechnology (KRIBB), Jeongeup 580-185, South Korea
| | - Min-Sung Kwon
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Uroos Akber
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Hyun-Su Lee
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Do-Sim Park
- Department of Laboratory Medicine, School of Medicine, Wonkwang University, Iksan 570-749, South Korea
| | - Woo Keun Song
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Zee-Yong Park
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Sin-Hyeog Im
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
| | - Mun-Chual Rho
- Department of Laboratory Medicine, School of Medicine, Wonkwang University, Iksan 570-749, South Korea
| | - Young-Min Hyun
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, NY 14642
| | - Minsoo Kim
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, NY 14642
| | - Chang-Duk Jun
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, South Korea
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12
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Robert P, Touchard D, Bongrand P, Pierres A. Biophysical description of multiple events contributing blood leukocyte arrest on endothelium. Front Immunol 2013; 4:108. [PMID: 23750158 PMCID: PMC3654224 DOI: 10.3389/fimmu.2013.00108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/26/2013] [Indexed: 12/16/2022] Open
Abstract
Blood leukocytes have a remarkable capacity to bind to and stop on specific blood vessel areas. Many studies have disclosed a key role of integrin structural changes following the interaction of rolling leukocytes with surface-bound chemoattractants. However, the functional significance of structural data and mechanisms of cell arrest are incompletely understood. Recent experiments revealed the unexpected complexity of several key steps of cell-surface interaction: (i) ligand-receptor binding requires a minimum amount of time to proceed and this is influenced by forces. (ii) Also, molecular interactions at interfaces are not fully accounted for by the interaction properties of soluble molecules. (iii) Cell arrest depends on nanoscale topography and mechanical properties of the cell membrane, and these properties are highly dynamic. Here, we summarize these results and we discuss their relevance to recent functional studies of integrin-receptor association in cells from a patient with type III leukocyte adhesion deficiency. It is concluded that an accurate understanding of all physical events listed in this review is needed to unravel the precise role of the multiple molecules and biochemical pathway involved in arrest triggering.
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Affiliation(s)
- Philippe Robert
- Laboratoire Adhésion and Inflammation, Aix-Marseille Université Marseille, France ; Institut National de la Santé et de la Recherche Médicale Marseille, France ; Centre National de la Recherche Scientifique Marseille, France ; Laboratoire d'Immunologie, Hôpitaux de Marseille, Hôpital de la Conception Marseille, France
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13
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Mizesko MC, Banerjee PP, Monaco-Shawver L, Mace EM, Bernal WE, Sawalle-Belohradsky J, Belohradsky BH, Heinz V, Freeman AF, Sullivan KE, Holland SM, Torgerson TR, Al-Herz W, Chou J, Hanson IC, Albert MH, Geha RS, Renner ED, Orange JS. Defective actin accumulation impairs human natural killer cell function in patients with dedicator of cytokinesis 8 deficiency. J Allergy Clin Immunol 2013; 131:840-8. [PMID: 23380217 PMCID: PMC3646579 DOI: 10.1016/j.jaci.2012.12.1568] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 12/21/2012] [Accepted: 12/27/2012] [Indexed: 11/23/2022]
Abstract
BACKGROUND Dedicator of cytokinesis 8 (DOCK8) mutations are responsible for a rare primary combined immunodeficiency syndrome associated with severe cutaneous viral infections, increased IgE levels, autoimmunity, and malignancy. Natural killer (NK) cells are essential for tumor surveillance and defense against virally infected cells. NK cell function relies on Wiskott-Aldrich syndrome protein for filamentous actin (F-actin) accumulation at the lytic NK cell immunologic synapse. DOCK8 activates cell division cycle 42, which, together with Wiskott-Aldrich syndrome protein, coordinates F-actin reorganization. Although abnormalities in T- and B-cell function have been described in DOCK8-deficient patients, the role of NK cells in this disease is unclear. OBJECTIVES We sought to understand the role of DOCK8 in NK cell function to determine whether NK cell abnormalities explain the pathogenesis of the clinical syndrome of DOCK8 deficiency. METHODS A cohort of DOCK8-deficient patients was assembled, and patients' NK cells, as well as NK cell lines with stably reduced DOCK8 expression, were studied. NK cell cytotoxicity, F-actin content, and lytic immunologic synapse formation were measured. RESULTS DOCK8-deficient patients' NK cells and DOCK8 knockdown cell lines all had decreased NK cell cytotoxicity, which could not be restored after IL-2 stimulation. Importantly, DOCK8 deficiency impaired F-actin accumulation at the lytic immunologic synapse without affecting overall NK cell F-actin content. CONCLUSIONS DOCK8 deficiency results in severely impaired NK cell function because of an inability to form a mature lytic immunologic synapse through targeted synaptic F-actin accumulation. This defect might underlie and explain important attributes of the DOCK8 deficiency clinical syndrome, including the unusual susceptibility to viral infection and malignancy.
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Affiliation(s)
- Melissa C. Mizesko
- Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | - Pinaki P. Banerjee
- Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | | | - Emily M. Mace
- Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | - William E. Bernal
- Children’s Hospital of Philadelphia Research Institute, Philadelphia, PA, USA
| | | | | | - Valerie Heinz
- University Children’s Hospital, Ludwig Maximilian University, Munich, Germany
| | - Alexandra F. Freeman
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | | | - Steven M. Holland
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Troy R. Torgerson
- University of Washington and Seattle Children’s Hospital, Seattle, WA, USA
| | - Waleed Al-Herz
- Pediatrics Department, Faculty of Medicine, Kuwait University, Kuwait
| | - Janet Chou
- Boston Children’s Hospital, Boston, MA, USA
| | - Imelda C. Hanson
- Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | - Michael H. Albert
- University Children’s Hospital, Ludwig Maximilian University, Munich, Germany
| | | | - Ellen D. Renner
- University Children’s Hospital, Ludwig Maximilian University, Munich, Germany
| | - Jordan S. Orange
- Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
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14
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Romanova LY, Mushinski JF. Central role of paxillin phosphorylation in regulation of LFA-1 integrins activity and lymphocyte migration. Cell Adh Migr 2012; 5:457-62. [PMID: 22274710 DOI: 10.4161/cam.5.6.18219] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Coordinated changes of actin cytoskeleton and cell adhesion accompany maturation of lymphoid cells, their migration through lymphoid organs and to sites of inflammation, as well as metastasis of transformed cells. Here we discuss the central role of the actin-regulating adaptor protein, paxillin, during lymphocyte transition from a polarized, motile cell phenotype with partially active LFA-1 integrins to a round and immobile one with fully active LFA-1. In Baf3 murine pro-B lymphocytes, the former phenotype is induced by IL-3 that stimulates a FAK-mediated phosphorylation of paxillin at tyrosines (Y) 31 and 118 and a consequent Rac1 activation. Rearrangements of actin cytoskeleton that lead to the cell's acquisition of a spherical shape and LFA-1 activation are achieved upon activation of PKC-δ that binds and directly phosphorylates paxillin at threonine (T) 538 with consequent RhoA activation. This is accompanied by dephosphorylation of paxillin Y31/118 and by Rac1 inactivation. We propose a model of signaling cascades that reflects the interplay between the IL-3- and PKC-δ-mediated pathways.
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Affiliation(s)
- Larisa Y Romanova
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, NIH, Bethesda, MD, USA.
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15
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Lateral mobility of individual integrin nanoclusters orchestrates the onset for leukocyte adhesion. Proc Natl Acad Sci U S A 2012; 109:4869-74. [PMID: 22411821 DOI: 10.1073/pnas.1116425109] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Integrins are cell membrane adhesion receptors involved in morphogenesis, immunity, tissue healing, and metastasis. A central, yet unresolved question regarding the function of integrins is how these receptors regulate both their conformation and dynamic nanoscale organization on the membrane to generate adhesion-competent microclusters upon ligand binding. Here we exploit the high spatial (nanometer) accuracy and temporal resolution of single-dye tracking to dissect the relationship between conformational state, lateral mobility, and microclustering of the integrin receptor lymphocyte function-associated antigen 1 (LFA-1) expressed on immune cells. We recently showed that in quiescent monocytes, LFA-1 preorganizes in nanoclusters proximal to nanoscale raft components. We now show that these nanoclusters are primarily mobile on the cell surface with a small (ca. 5%) subset of conformational-active LFA-1 nanoclusters preanchored to the cytoskeleton. Lateral mobility resulted crucial for the formation of microclusters upon ligand binding and for stable adhesion under shear flow. Activation of high-affinity LFA-1 by extracellular Ca(2+) resulted in an eightfold increase on the percentage of immobile nanoclusters and cytoskeleton anchorage. Although having the ability to bind to their ligands, these active nanoclusters failed to support firm adhesion in static and low shear-flow conditions because mobility and clustering capacity were highly compromised. Altogether, our work demonstrates an intricate coupling between conformation and lateral diffusion of LFA-1 and further underscores the crucial role of mobility for the onset of LFA-1 mediated leukocyte adhesion.
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16
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Pazdrak K, Young TW, Straub C, Stafford S, Kurosky A. Priming of eosinophils by GM-CSF is mediated by protein kinase CbetaII-phosphorylated L-plastin. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2011; 186:6485-96. [PMID: 21525390 PMCID: PMC3100773 DOI: 10.4049/jimmunol.1001868] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The priming of eosinophils by cytokines leading to augmented response to chemoattractants and degranulating stimuli is a characteristic feature of eosinophils in the course of allergic inflammation and asthma. Actin reorganization and integrin activation are implicated in eosinophil priming by GM-CSF, but their molecular mechanism of action is unknown. In this regard, we investigated the role of L-plastin, an eosinophil phosphoprotein that we identified from eosinophil proteome analysis. Phosphoproteomic analysis demonstrated the upregulation of phosphorylated L-plastin after eosinophil stimulation with GM-CSF. Additionally, coimmunoprecipitation studies demonstrated a complex formation of phosphorylated L-plastin with protein kinase CβII (PKCβII), GM-CSF receptor α-chain, and two actin-associated proteins, paxilin and cofilin. Inhibition of PKCβII with 4,5-bis(4-fluoroanilino)phtalimide or PKCβII-specific small interfering RNA blocked GM-CSF-induced phosphorylation of L-plastin. Furthermore, flow cytometric analysis also showed an upregulation of α(M)β(2) integrin, which was sensitive to PKCβII inhibition. In chemotaxis assay, GM-CSF treatment allowed eosinophils to respond to lower concentrations of eotaxin, which was abrogated by the above-mentioned PKCβII inhibitors. Similarly, inhibition of PKCβII blocked GM-CSF induced priming for degranulation as assessed by release of eosinophil cationic protein and eosinophil peroxidase in response to eotaxin. Importantly, eosinophil stimulation with a synthetic L-plastin peptide (residues 2-19) phosphorylated on Ser(5) upregulated α(M)β(2) integrin expression and increased eosinophil migration in response to eotaxin independent of GM-CSF stimulation. Our results establish a causative role for PKCβII and L-plastin in linking GM-CSF-induced eosinophil priming for chemotaxis and degranulation to signaling events associated with integrin activation via induction of PKCβII-mediated L-plastin phosphorylation.
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Affiliation(s)
- Konrad Pazdrak
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
- UTMB National Heart, Lung, and Blood Institute Proteomics Center, University of Texas Medical Branch, Galveston, TX 77555
| | - Travis W. Young
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
- UTMB National Heart, Lung, and Blood Institute Proteomics Center, University of Texas Medical Branch, Galveston, TX 77555
| | - Christof Straub
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
- UTMB National Heart, Lung, and Blood Institute Proteomics Center, University of Texas Medical Branch, Galveston, TX 77555
| | - Susan Stafford
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
- UTMB National Heart, Lung, and Blood Institute Proteomics Center, University of Texas Medical Branch, Galveston, TX 77555
| | - Alexander Kurosky
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
- UTMB National Heart, Lung, and Blood Institute Proteomics Center, University of Texas Medical Branch, Galveston, TX 77555
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17
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Robert P, Canault M, Farnarier C, Nurden A, Grosdidier C, Barlogis V, Bongrand P, Pierres A, Chambost H, Alessi MC. A novel leukocyte adhesion deficiency III variant: kindlin-3 deficiency results in integrin- and nonintegrin-related defects in different steps of leukocyte adhesion. THE JOURNAL OF IMMUNOLOGY 2011; 186:5273-83. [PMID: 21441448 DOI: 10.4049/jimmunol.1003141] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Leukocyte adhesion deficiency type III is a recently described condition involving a Glanzmann-type bleeding syndrome and leukocyte adhesion deficiency. This was ascribed to a defect of the FERMT3 gene resulting in abnormal expression of kindlin-3, a protein expressed in hematopoietic cells with a major role in the regulation of integrin activation. In this article, we describe a patient with a new mutation of FERMT3 and lack of kindlin-3 expression in platelets and leukocytes. We assayed quantitatively the first steps of kindlin-3-defective leukocyte adhesion, namely, initial bond formation, bond strengthening, and early spreading. Initial bond formation was readily stimulated with neutrophils stimulated by fMLF, and neutrophils and lymphocytes stimulated by a phorbol ester or Mn(2+). In contrast, attachment strengthening was defective in the patient's lymphocytes treated with PMA or Mn(2+), or fMLF-stimulated neutrophils. However, attachment strengthening was normal in patient's neutrophils treated with phorbol ester or Mn(2+). In addition, the patient's T lymphocytes displayed defective integrin-mediated spreading and a moderate but significant decrease of spreading on anti-CD3-coated surfaces. Patient's neutrophils displayed a drastic alteration of integrin-mediated spreading after fMLF or PMA stimulation, whereas signaling-independent Mn(2+) allowed significant spreading. In conclusion, the consequences of kindlin-3 deficiency on β(2) integrin function depend on both cell type and the stimulus used for integrin activation. Our results suggest looking for a possible kindlin-3 involvement in membrane dynamical event independent of integrin-mediated adhesion.
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Affiliation(s)
- Philippe Robert
- Laboratoire d'Immunologie, Hôpital de la Conception, Assistance Publique-Hôpitaux de Marseille, 13385 Marseille Cedex 05, France
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18
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Hart R, Greaves DR. Chemerin contributes to inflammation by promoting macrophage adhesion to VCAM-1 and fibronectin through clustering of VLA-4 and VLA-5. THE JOURNAL OF IMMUNOLOGY 2010; 185:3728-39. [PMID: 20720202 DOI: 10.4049/jimmunol.0902154] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chemerin is a potent macrophage chemoattractant protein. We used murine peritoneal exudate cells (PECs) in adhesion, flow cytometry, and confocal microscopy assays to test the hypothesis that chemerin can also contribute to inflammation by promoting macrophage adhesion. Chemerin stimulated the adhesion of PECs to the extracellular matrix protein fibronectin and to the adhesion molecule VCAM-1 within a minute, with an EC(50) of 322 and 196 pM, respectively. Experiments using pertussis toxin and PECs from ChemR23(-/-) mice demonstrated that chemerin stimulated the adhesion of macrophages via the Gi protein-coupled receptor ChemR23. Blocking Abs against integrin subunits revealed that 89% of chemerin-stimulated adhesion to fibronectin was dependent on increased avidity of the integrin VLA-5 (alpha(5)beta(1)) and that 88% of adhesion to VCAM-1 was dependent on increased avidity of VLA-4 (alpha(4)beta(1)). Although chemerin was unable to induce an increase in integrin affinity as judged by the binding of soluble ligand, experiments using confocal microscopy revealed an increase in valency resulting from integrin clustering as the mechanism responsible for chemerin-stimulated macrophage adhesion. PI3K, Akt, and p38 were identified as key signaling mediators in chemerin-stimulated adhesion. The finding that chemerin can rapidly stimulate macrophage adhesion to extracellular matrix proteins and adhesion molecules, taken together with its ability to promote chemotaxis, suggests a novel role for chemerin in the recruitment and retention of macrophages at sites of inflammation.
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Affiliation(s)
- Rosie Hart
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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19
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Wabnitz GH, Lohneis P, Kirchgessner H, Jahraus B, Gottwald S, Konstandin M, Klemke M, Samstag Y. Sustained LFA-1 cluster formation in the immune synapse requires the combined activities of L-plastin and calmodulin. Eur J Immunol 2010; 40:2437-49. [DOI: 10.1002/eji.201040345] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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20
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Yu T, Wu X, Gupta KB, Kucik DF. Affinity, lateral mobility, and clustering contribute independently to beta 2-integrin-mediated adhesion. Am J Physiol Cell Physiol 2010; 299:C399-410. [PMID: 20445173 DOI: 10.1152/ajpcell.00039.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Affinity changes and avidity modulation both contribute to activation of beta(2)-integrin-mediated adhesion, an essential, early step in inflammation. Avidity modulation, defined as an increase in adhesiveness independent of integrin conformational changes, might be due to integrin clustering, motion, or both. Increased integrin diffusion upon leukocyte activation has been demonstrated, but whether it is proadhesive in itself, or just constitutes a mechanism for integrin clustering, remains unclear. To understand the proadhesive effects of integrin affinity changes, clustering, and motion, an experimental system was devised to separate them. Clustering and integrin motion together were induced by cytochalasin D (CD) without inducing high-affinity; integrin motion could then be frozen by fixation; and high affinity was induced independently by Mn(2+). Adhesion was equivalent for fixed and unfixed cells except following pretreatment with CD or Mn(2+), which increased adhesion for both. However, fixed cells were less adhesive than unfixed cells after CD, even though integrin clustering was similar. A simple explanation is that CD induces both clustering and integrin motion, fixation then stops motion on fixed cells, but integrins continue to diffuse on unfixed cells, increasing the kinetics of integrin/ICAM-1 interactions to enhance adhesion. Affinity changes are then independent of, and additive to, avidity effects.
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Affiliation(s)
- Tao Yu
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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21
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Romanova LY, Holmes G, Bahte SK, Kovalchuk AL, Nelson PJ, Ward Y, Gueler F, Mushinski JF. Phosphorylation of paxillin at threonine 538 by PKCdelta regulates LFA1-mediated adhesion of lymphoid cells. J Cell Sci 2010; 123:1567-77. [PMID: 20388733 DOI: 10.1242/jcs.060996] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We investigated the PKCdelta-mediated phosphorylation of paxillin within its LIM4 domain and the involvement of this phosphorylation in activation of LFA-1 integrins of the Baf3 pro-B lymphocytic cell line. Using phosphorylated-threonine-specific antibodies, phosphorylated amino acid analysis and paxillin phosphorylation mutants, we demonstrated that TPA, the pharmacological analog of the endogenous second messenger diacyl glycerol, stimulates paxillin phosphorylation at threonine 538 (T538). The TPA-responsive PKC isoform PKCdelta directly binds paxillin in a yeast two-hybrid assay and phosphorylates paxillin at T538 in vitro and also co-immunoprecipitates with paxillin and mediates phosphorylation of this residue in vivo. Recombinant wild-type paxillin, its phospho-inhibitory T538A or phospho-mimetic T538E mutants were expressed in the cells simultaneously with siRNA silencing of the endogenous paxillin. These experiments suggest that phosphorylation of paxillin T538 contributes to dissolution of the actin cytoskeleton, redistribution of LFA-1 integrins and an increase in their affinity. We also show that phosphorylation of T538 is involved in the activation of LFA-1 integrins by TPA.
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Affiliation(s)
- Larisa Y Romanova
- Laboratory of Cancer Biology and Genetics, Cell and Cancer Biology Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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22
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Tu QV, Okoli AS, Kovach Z, Mendz GL. Hepatocellular carcinoma: prevalence and molecular pathogenesis of Helicobacter spp. Future Microbiol 2009; 4:1283-301. [PMID: 19995189 DOI: 10.2217/fmb.09.90] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori infection is one of the most common chronic bacterial infections in humans. The association of other Helicobacter spp. with extragastric diseases in animals is well established, and a role of these bacteria in human liver disease is becoming clearer. Several case-control studies have reported possible associations of Helicobacter spp. with various liver diseases, including hepatocellular carcinoma, which is the fifth most common type of carcinoma among men worldwide, and the eighth most common among women. Thus, it is important to understand molecular mechanisms that may lead to hepatotoxicity or hepatocellular dysfunction in which Helicobacter spp. may play a role in inducing malignant transformation of liver cells.
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Affiliation(s)
- Quoc V Tu
- School of Medical Sciences, The University of New South Wales, Sydney, NSW 2052, Australia.
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23
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The multifaceted profile of activated microglia. Mol Neurobiol 2009; 40:139-56. [PMID: 19629762 DOI: 10.1007/s12035-009-8077-9] [Citation(s) in RCA: 204] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Accepted: 06/17/2009] [Indexed: 12/17/2022]
Abstract
Although relatively neglected previously, research efforts in the past decade or so have identified a pivotal role for glial cells in regulating neuronal function. Particular emphasis has been placed on increasing our understanding of the function of microglia because a change from the ramified "resting" state of these cells has been associated with the pathogenesis of several neurodegenerative diseases, notably Alzheimer's disease. However, it is not clear whether activation of microglia and the associated inflammatory changes play a part in triggering disease processes or whether cell activation is a response to the early changes associated with the disease. In either case, the possibility exists that modulation of microglial activation may be beneficial in some circumstances, underlying the need to pursue research in this area. The original morphological categorization of microglia by Del Rio Hortega into ameboid, ramified, and intermediate forms, must now be elaborated to encompass a functional description. The evidence which has been generated recently suggests that microglia are probably never in a "resting" state and that several intermediate transitional states, based on function and morphology, probably exist. A more complete understanding of these states and the triggers which lead to a change from one to another state, and the factors which modulate the molecular switch that determines the persistence of the "activated" state remain to be identified.
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24
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Lobo EO, Zhang Z, Shively JE. Pivotal advance: CEACAM1 is a negative coreceptor for the B cell receptor and promotes CD19-mediated adhesion of B cells in a PI3K-dependent manner. J Leukoc Biol 2009; 86:205-18. [PMID: 19454653 DOI: 10.1189/jlb.0109037] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Upon antigen binding, the BCR transduces a signal culminating in proliferation or in AICD of the B cell. Coreceptor engagement and subsequent modification of the BCR signal pathway are mechanisms that guide the B cell to its appropriate fate. For example, in the absence of coreceptor engagement, anti-sIgM antibodies induce apoptosis in the human Daudi B cell lymphoma cell line. ITIM-bearing B cell coreceptors that potentially may act as negative coreceptors include FcRgammaIIb, CD22, CD72, and CEACAM1 (CD66a). Although the role of CEACAM1 as an inhibitory coreceptor in T cells has been established, its role in B cells is poorly defined. We show that anti-sIgM antibody and PI3K inhibitor LY294002-induced apoptosis are reduced significantly in CEACAM1 knock-down clones compared with WT Daudi cells and that anti-sIgM treatment induced CEACAM1 tyrosine phosphorylation and association with SHP-1 in WT cells. In contrast, treatment of WT Daudi cells with anti-CD19 antibodies does not induce apoptosis and has reduced tyrosine phosphorylation and SHP-1 recruitment to CEACAM1. Thus, similar to its function in T cells, CEACAM1 may act as an inhibitory B cell coreceptor, most likely through recruitment of SHP-1 and inhibition of a PI3K-promoted activation pathway. Activation of B cells by anti-sIgM or anti-CD19 antibodies also leads to cell aggregation that is promoted by CEACAM1, also in a PI3K-dependent manner.
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Affiliation(s)
- Elizabeth O Lobo
- Division of Immunology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA
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25
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Sarantos MR, Zhang H, Schaff UY, Dixit N, Hayenga HN, Lowell CA, Simon SI. Transmigration of neutrophils across inflamed endothelium is signaled through LFA-1 and Src family kinase. THE JOURNAL OF IMMUNOLOGY 2009; 181:8660-9. [PMID: 19050286 DOI: 10.4049/jimmunol.181.12.8660] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Leukocyte capture on inflamed endothelium is facilitated by a shift in LFA-1 from low to high affinity that supports binding to ICAM-1. LFA-1 bonds help anchor polymorphonuclear leukocytes (PMN) to inflamed endothelium in shear flow, and their redistribution to the leading edge guides pseudopod formation, migration, and extravasation. These events can be disrupted at the plasma membrane by stabilizing LFA-1 in a low- or intermediate-affinity state with allosteric small molecules. We hypothesized that a minimum dimeric bond formation between high-affinity LFA-1 and ICAM-1 under shear stress is necessary to catalyze transmembrane signaling of directed cell migration. Microspheres and substrates were derivatized with monomeric or dimeric ICAM-1 to simulate the surface of inflamed endothelium under defined ligand valence. Binding to dimeric ICAM-1, and not monomeric ICAM-1, was sufficient to elicit assembly of F-actin and phosphorylation of Src family kinases that colocalized with LFA-1 on adherent PMN. Genetic deletion or small molecule inhibition of Src family kinases disrupted their association with LFA-1 that correlated with diminished polarization of arrested PMN and abrogation of transmigration on inflamed endothelium. We conclude that dimeric bond clusters of LFA-1/ICAM-1 provide a key outside-in signal for orienting cytoskeletal dynamics that direct PMN extravasation at sites of inflammation.
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Affiliation(s)
- Melissa R Sarantos
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
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26
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Gill KS, Beier F, Goldberg HA. Rho-ROCK signaling differentially regulates chondrocyte spreading on fibronectin and bone sialoprotein. Am J Physiol Cell Physiol 2008; 295:C38-49. [PMID: 18463228 DOI: 10.1152/ajpcell.00548.2007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The mammalian growth plate is a dynamic structure rich in extracellular matrix (ECM). Interactions of growth plate chondrocytes with ECM proteins regulate cell behavior. In this study, we compared chondrocyte adhesion and spreading dynamics on fibronectin (FN) and bone sialoprotein (BSP). Chondrocyte adhesion and spreading were also compared with fibroblasts to analyze potential cell-type-specific effects. Chondrocyte adhesion to BSP is independent of posttranslational modifications but is dependent on the RGD sequence in BSP. Whereas chondrocytes and fibroblasts adhered at similar levels on FN and BSP, cells displayed more actin-dependent spread on FN despite a 16x molar excess of BSP adsorbed to plastic. To identify intracellular mediators responsible for this difference in spreading, we investigated focal adhesion kinase (FAK)-Src and Rho-Rho kinase (ROCK) signaling. Although activated FAK localized to the vertices of adhered chondrocytes, levels of FAK activation did not correlate with the extent of spreading. Furthermore, Src inhibition reduced chondrocyte spreading on both FN and BSP, suggesting that FAK-Src signaling is not responsible for less cell spreading on BSP. In contrast, inhibition of Rho and ROCK in chondrocytes increased cell spreading on BSP and membrane protrusiveness on FN but did not affect cell adhesion. In fibroblasts, Rho inhibition increased fibroblast spreading on BSP while ROCK inhibition changed membrane protrusiveness of FN and BSP. In summary, we identify a novel role for Rho-ROCK signaling in regulating chondrocyte spreading and demonstrate both cell- and matrix molecule-specific mechanisms controlling cell spreading.
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Affiliation(s)
- Kamal S Gill
- CIHR Group in Skeletal Development and Remodeling, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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27
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Pec MK, Artwohl M, Fernández JJ, Souto ML, Alvarez de la Rosa D, Giraldez T, Valenzuela-Fernández A, Díaz-González F. Chemical modulation of VLA integrin affinity in human breast cancer cells. Exp Cell Res 2007; 313:1121-34. [PMID: 17331499 DOI: 10.1016/j.yexcr.2007.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 01/02/2007] [Accepted: 01/21/2007] [Indexed: 12/31/2022]
Abstract
The fact that disruption of integrin-extracellular matrix contacts leads to cell death, has converted cell adhesion into a potential target for the control of invasive cancer. In this work, we studied the functional consequences of the interference with the activity of the very late activation antigen (VLA) family of integrins in human breast cancer cell lines of distinct malignancy. The alpha2beta1-mediated adhesion reduced the entry of highly malignant, hormone-independent breast cancer cells into apoptosis. Adhesion of breast cancer cells through the VLA integrins alpha2beta1 and alpha5beta1 was significantly reduced by an apoptosis-inducing natural triterpenoid, dehydrothyrsiferol (DT), when studied on low amounts of extracellular matrix. This effect was dose-dependent, not related to cell toxicity and not shared with apoptosis-inducing standard chemotherapeutics, such as doxorubicin and taxol. The compound did not affect either the cell surface expression level of VLA integrins or cell distribution of vinculin and actin during cell spreading. In addition, neither phosphorylation of the focal adhesion kinase pp125FAK on Tyr397 nor the protein kinase B (Akt/PKB) on Ser473 was significantly altered by DT. The integrin activation level, assessed by binding of soluble collagen to the alpha2beta1 integrin, was reduced upon cell treatment with DT. Importantly, the TS2/16, an anti-beta1 activating monoclonal antibody was able to rescue DT-treated cells from apoptosis. Since the activation state of integrins is increasingly recognized as an essential factor in metastasis formation, findings presented herein reveal that the chemical regulation of integrin affinity may be a potential therapeutic strategy in cancer therapy.
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Affiliation(s)
- Martina K Pec
- Servicio de Reumatología, Hospital Universitario de Canarias, C/Ofra s/n, La Cuesta, 38320 La Laguna, Santa Cruz de Tenerife, Spain
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28
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Simonson WTN, Franco SJ, Huttenlocher A. Talin1 regulates TCR-mediated LFA-1 function. THE JOURNAL OF IMMUNOLOGY 2007; 177:7707-14. [PMID: 17114441 DOI: 10.4049/jimmunol.177.11.7707] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The leukocyte integrin LFA-1 plays a critical role in T cell trafficking and T cell adhesion to APCs. It is known that integrin-mediated adhesion is regulated by changes in integrin ligand-binding affinity and valency through inside-out signaling. However, the molecular mechanisms involved in TCR-mediated LFA-1 regulation are not well understood. In this study, we show that the cytoskeletal protein talin1 is required for TCR-mediated activation of LFA-1 through regulation of LFA-1 affinity and clustering. Depletion of talin1 from human T cells by small interfering RNAs impairs TCR-induced adhesion to ICAM-1 and T cell-APC conjugation. TCR-induced LFA-1 polarization, but not actin polarization, is defective in talin1-deficient T cells. Although LFA-1 affinity is also reduced in talin1-deficient T cells, rescue of LFA-1 affinity alone is not sufficient to restore LFA-1 adhesive function. Together, our findings indicate that TCR-induced up-regulation of LFA-1-dependent adhesiveness and resulting T cell-APC conjugation require talin1.
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Affiliation(s)
- William T N Simonson
- Program in Cellular and Molecular Biology, University of Wisconsin, 1300 University Avenue, Madison, WI 53706, USA
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29
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Weigel-Kelley KA, Yoder MC, Chen L, Srivastava A. Role of integrin cross-regulation in parvovirus B19 targeting. Hum Gene Ther 2006; 17:909-20. [PMID: 16972759 DOI: 10.1089/hum.2006.17.909] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Most viral vectors used for gene therapy lack the ability to target a defined cell population. Parvovirus B19 has a restricted tropism for human erythroid progenitor cells and uses activated alpha5beta1 integrins as coreceptors for entry [Weigel-Kelley, K.A., Yoder, M.C., and Srivastava, A. (2003). Blood 102, 3927-3933]. In this study we examined the role of coexpressed integrins in alpha5beta1 integrin coreceptor function. Antibody-mediated cross-linking of beta1, beta2, and beta3 integrins and the integrin-associated protein (IAP) increased parvovirus B19 entry into nontarget K562 cells. Functional silencing of one integrin group, however, reduced the virus uptake- promoting function of a subsequently activated integrin group, indicating that the three integrins did not operate in isolation but through shared signaling pathways. This was further corroborated by direct competition between simultaneously clustered beta2 and beta1 integrins that could be overcome by stabilizing clustered beta1 integrins in a high-affinity conformation. In contrast, parvovirus B19 entry into primary erythroid progenitor cells was characterized by strong clustering-induced beta1 integrin coreceptor activity that was not abolished by subsequent beta2 and beta3 integrin activation and was, in fact, substantially increased in the presence of preclustered beta2 and beta3 integrins. Thus, integrin function is regulated in a cell type-specific manner through coexpressed integrins and preferential parvovirus B19 entry into erythroid progenitor cells is promoted by a robust beta1 integrin response that is enhanced through stable preclustering of coexpressed integrins. These results have implications for other viral vectors that use integrins as receptors/coreceptors and for gene therapy of hematopoietic progenitor cells using parvovirus B19 vectors.
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Affiliation(s)
- Kirsten A Weigel-Kelley
- Division of Cellular and Molecular Therapy, Department of Pediatrics, Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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Hyduk SJ, Chan JR, Duffy ST, Chen M, Peterson MD, Waddell TK, Digby GC, Szaszi K, Kapus A, Cybulsky MI. Phospholipase C, calcium, and calmodulin are critical for α4β1 integrin affinity up-regulation and monocyte arrest triggered by chemoattractants. Blood 2006; 109:176-84. [PMID: 16960156 DOI: 10.1182/blood-2006-01-029199] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractDuring inflammation, monocytes roll on activated endothelium and arrest after stimulation by proteoglycan-bound chemokines and other chemoattractants. We investigated signaling pathways downstream of G protein–coupled receptors (GPCRs) that are relevant to α4β1 integrin affinity up-regulation using formyl peptide receptor-transfected U937 cells stimulated with fMLP or stromal-derived factor-1α and human peripheral blood monocytes stimulated with multiple chemokines or chemoattractants. The up-regulation of soluble LDV peptide or vascular cell adhesion molecule-1 (VCAM-1) binding by these stimuli was critically dependent on activation of phospholipase C (PLC), inositol 1,4,5-triphosphate receptors, increased intracellular calcium, influx of extracellular calcium, and calmodulin, suggesting that this signaling pathway is required for α4 integrins to assume a high-affinity conformation. In fact, a rise in intracellular calcium following treatment with thapsigargin or ionomycin was sufficient to induce binding of ligand. Blockade of p44/42 and p38 mitogen-activated protein (MAP) kinases, phosphoinositide 3-kinase, or protein kinase C (PKC) signaling did not inhibit chemoattractant-induced LDV or VCAM-1 binding. However, activation of PKC by phorbol ester up-regulated α4β1 affinity with kinetics distinct from those of GPCR signaling. A critical role for PLC and calmodulin was also established for leukocyte arrest and adhesion strengthening.
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Affiliation(s)
- Sharon J Hyduk
- Department of Laboratory Medicine and Pathobiology, University of Toronto, ON, Canada
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31
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Weigel-Kelley KA, Yoder MC, Chen L, Srivastava A. Role of Integrin Cross-Regulation in Parvovirus B19 Targeting. Hum Gene Ther 2006. [DOI: 10.1089/hum.2006.17.ft-236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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32
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Zecchinon L, Fett T, Vanden Bergh P, Desmecht D. Bind another day: The LFA-1/ICAM-1 interaction as therapeutic target. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.cair.2006.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Ada-Nguema AS, Xenias H, Hofman JM, Wiggins CH, Sheetz MP, Keely PJ. The small GTPase R-Ras regulates organization of actin and drives membrane protrusions through the activity of PLCepsilon. J Cell Sci 2006; 119:1307-19. [PMID: 16537651 DOI: 10.1242/jcs.02835] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
R-Ras, an atypical member of the Ras subfamily of small GTPases, enhances integrin-mediated adhesion and signaling through a poorly understood mechanism. Dynamic analysis of cell spreading by total internal reflection fluorescence (TIRF) microscopy demonstrated that active R-Ras lengthened the duration of initial membrane protrusion, and promoted the formation of a ruffling lamellipod, rich in branched actin structures and devoid of filopodia. By contrast, dominant-negative R-Ras enhanced filopodia formation. Moreover, RNA interference (RNAi) approaches demonstrated that endogenous R-Ras contributed to cell spreading. These observations suggest that R-Ras regulates membrane protrusions through organization of the actin cytoskeleton. Our results suggest that phospholipase Cepsilon (PLCepsilon) is a novel R-Ras effector mediating the effects of R-Ras on the actin cytoskeleton and membrane protrusion, because R-Ras was co-precipitated with PLCepsilon and increased its activity. Knockdown of PLCepsilon with siRNA reduced the formation of the ruffling lamellipod in R-Ras cells. Consistent with this pathway, inhibitors of PLC activity, or chelating intracellular Ca2+ abolished the ability of R-Ras to promote membrane protrusions and spreading. Overall, these data suggest that R-Ras signaling regulates the organization of the actin cytoskeleton to sustain membrane protrusion through the activity of PLCepsilon.
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Affiliation(s)
- Aude S Ada-Nguema
- Department of Pharmacology, University of Wisconsin-Madison, Madison, WI 53706, USA
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Konstandin MH, Sester U, Klemke M, Weschenfelder T, Wabnitz GH, Samstag Y. A novel flow-cytometry-based assay for quantification of affinity and avidity changes of integrins. J Immunol Methods 2006; 310:67-77. [PMID: 16458321 DOI: 10.1016/j.jim.2005.12.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 11/22/2005] [Accepted: 12/02/2005] [Indexed: 10/25/2022]
Abstract
Cell adhesion plays an important role in cell-cell contact formation and cell migration. Thus, the assessment of cellular adhesiveness is one important feature when studying cell-mediated immune responses. The interaction of lymphocytes with other cell types such as antigen-presenting cells or vascular-endothelial cells occurs via adhesion molecules including L-selectin, VCAM-1 or ICAM-1. There are principally two mechanisms by which cell adhesion can be enhanced: namely changes in the affinity or avidity of receptor interactions. Conventional plate-based adhesion assays detect both forms. However, they do not permit discrimination between affinity- and avidity-mediated changes in the adhesiveness. Moreover, analysis of cell subpopulations requires cell separation prior to performance of the adhesion assay. Conventional flow-cytometry-based tests make it possible to determine changes in the affinity of integrins at the single cell level. However, they fail to quantify avidity-mediated adhesiveness. Here we describe a novel flow-cytometry-based assay, which allows the detection of both integrin-mediated affinity as well as avidity changes at the single cell level. This opens up the possibility of precisely characterizing the adhesive capacity of subpopulations in heterogeneous cell populations.
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Affiliation(s)
- M H Konstandin
- Institute for Immunology, Ruprecht-Karls-University, Heidelberg, Germany
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Parameswaran N, Suresh R, Bal V, Rath S, George A. Lack of ICAM-1 on APCs during T cell priming leads to poor generation of central memory cells. THE JOURNAL OF IMMUNOLOGY 2005; 175:2201-11. [PMID: 16081787 DOI: 10.4049/jimmunol.175.4.2201] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
ICAM-1/LFA-1 interactions are known to enhance T cell/APC interactions and to promote T cell activation and cytokine secretion. We have analyzed the consequences of ICAM-1-mediated signaling on the generation of memory T cell subsets. We report that lack of ICAM-1 on APCs, but not on T cells, leads to poor T cell activation and proliferation in vitro and in vivo, and that the defect can be compensated by Ag dose, exogenous IL-2, additional costimulation, and by increasing responder T cell density on APCs. ICAM-1-null mice do not respond to immunization with OVA peptide, but immunization with OVA or with Salmonella typhimurium leads to good T cell proliferation 7-10 days later, and clearance of a challenge infection is equivalent to that of wild-type mice. However, when followed over time, recall proliferation and antibacterial immunity decay rapidly in ICAM-1-null mice, while recall cytokine responses are unaffected. The decline in immunity is not related to poor survival of T cells activated on ICAM-1-null APCs, or to poor generation of effectors in ICAM-1-null mice. Phenotypic analysis of T cells stimulated on ICAM-1-null APCs reveals preferential generation of CD44(high) CD62L(low) effector memory cells (T(EM)) over CD44(high) CD62L(high) central memory cells (T(CM)). Further, while the proportion of naive:memory T cells is similar in unmanipulated wild-type and ICAM-1-null mice, there is an accumulation of T(EM) cells, and a high T(EM):T(CM) ratio in aging ICAM-1-null mice. Together, the data indicate that signaling through LFA-1 during T cell activation may be involved in commitment to a proliferation-competent memory pool.
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36
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Huber JD, Campos CR, Mark KS, Davis TP. Alterations in blood-brain barrier ICAM-1 expression and brain microglial activation after lambda-carrageenan-induced inflammatory pain. Am J Physiol Heart Circ Physiol 2005; 290:H732-40. [PMID: 16199477 PMCID: PMC3915803 DOI: 10.1152/ajpheart.00747.2005] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies showed that peripheral inflammatory pain increased blood-brain barrier (BBB) permeability and altered tight junction protein expression and the delivery of opioid analgesics to the brain. What remains unknown is which pathways and mediators during peripheral inflammation affect BBB function and structure. The current study investigated effects of lambda-carrageenan-induced inflammatory pain (CIP) on BBB expression of ICAM-1. We also examined the systemic contribution of a number of proinflammatory cytokines and microglial activation in the brain to elucidate pathways involved in BBB disruption during CIP. We investigated ICAM-1 RNA and protein expression levels in isolated rat brain microvessels after CIP using RT-PCR and Western blot analyses, screened inflammatory cytokines during the time course of inflammation, assessed white blood cell counts, and probed for BBB and central nervous system stimulation and leukocyte transmigration using immunohistochemistry and flow cytometry. Results showed an early increase in ICAM-1 RNA and protein expression after CIP with no change in circulating levels of several proinflammatory cytokines. Changes in ICAM-1 protein expression were noted at 48 h. Immunohistochemistry showed that the induction of ICAM-1 was region specific with increased expression noted in the thalamus and frontal and parietal cortices, which directly correlated with increased expression of activated microglia. The findings of the present study were that CIP induces increased ICAM-1 mRNA and protein expression at the BBB and that systemic proinflammatory mediators play no apparent role in the early response (1-6 h); however, brain region-specific increases in microglial activation suggest a potential for a central-mediated response.
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Affiliation(s)
- J. D. Huber
- Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, West Virginia
| | - C. R. Campos
- Department of Medical Pharmacology, University of Arizona, Tucson, Arizona
| | - K. S. Mark
- Department of Pharmacology, University of Missouri-Kansas City, Kansas City, Missouri
| | - T. P. Davis
- Department of Medical Pharmacology, University of Arizona, Tucson, Arizona
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Thamilselvan V, Basson MD. The role of the cytoskeleton in differentially regulating pressure-mediated effects on malignant colonocyte focal adhesion signaling and cell adhesion. Carcinogenesis 2005; 26:1687-97. [PMID: 15917311 DOI: 10.1093/carcin/bgi135] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Increased extracellular pressure stimulates colon cancer cell adhesion by activating focal adhesion kinase (FAK) and Src. We investigated the role of the cytoskeleton in pressure-induced inside-out FAK and Src phosphorylation and pressure-stimulated adhesion. We perturbed actin polymerization with phalloidin, cytochalasin D and latrunculin B, and microtubule organization with colchicine and paclitaxol. We compared the effects of these agents on pressure-induced SW620 and human primary colon cancer cell adhesion and inside-out FAK/Src activation with outside-in adhesion-dependent FAK/Src activation. Cells pretreated with cytoskeletal inhibitors were subjected to 15 mmHg increased pressure and allowed to adhere to collagen I coated plates or prevented from adhesion to pacificated plates for 30 min. Phalloidin, cytochalasin D, latrunculin B and colchicine pretreatment completely prevented pressure-stimulated and significantly inhibited basal SW620 cell adhesion. Taxol did not inhibit pressure-induced colon cancer cell adhesion, but significantly lowered basal adhesion. Cytochalasin D and colchicine had similar effects in pressure-stimulated primary human malignant colonocytes. Phalloidin, cytochalasin D, latrunculin B and colchicine prevented pressure-induced SW620 FAK phosphorylation but not Src phosphorylation. FAK phosphorylation in response to collagen I adhesion was significantly attenuated but not completely prevented by these inhibitors. Although Src phosphorylation was not increased on adhesion, the cytoskeleton disrupting agents significantly lowered basal Src phosphorylation in adherent cells. These results suggest that both cytoskeleton-dependent FAK activation and cytoskeleton-independent Src activation may be required for extracellular pressure to stimulate colon cancer cell adhesion. Furthermore, the cytoskeleton plays a different role in pressure-activated FAK and Src signaling than in FAK and Src activation in adherent cells. We, therefore, hypothesize that cytoskeletal interactions with focal adhesion signals mediate the effects of extracellular pressure on colon cancer cell adhesion.
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Affiliation(s)
- Vijayalakshmi Thamilselvan
- Department of Surgery, Wayne State University School of Medicine and John D.Dingell Veterans Affairs Medical Center, 4646 John R. Street, Detroit, MI 48201, USA
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38
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Shamri R, Grabovsky V, Gauguet JM, Feigelson S, Manevich E, Kolanus W, Robinson MK, Staunton DE, von Andrian UH, Alon R. Lymphocyte arrest requires instantaneous induction of an extended LFA-1 conformation mediated by endothelium-bound chemokines. Nat Immunol 2005; 6:497-506. [PMID: 15834409 DOI: 10.1038/ni1194] [Citation(s) in RCA: 317] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2004] [Accepted: 03/18/2005] [Indexed: 12/16/2022]
Abstract
It is widely believed that rolling lymphocytes require successive chemokine-induced signaling for lymphocyte function-associated antigen 1 (LFA-1) to achieve a threshold avidity that will mediate lymphocyte arrest. Using an in vivo model of lymphocyte arrest, we show here that LFA-1-mediated arrest of lymphocytes rolling on high endothelial venules bearing LFA-1 ligands and chemokines was abrupt. In vitro flow chamber models showed that endothelium-presented but not soluble chemokines triggered instantaneous extension of bent LFA-1 in the absence of LFA-1 ligand engagement. To support lymphocyte adhesion, this extended LFA-1 conformation required immediate activation by its ligand, intercellular adhesion molecule 1. These data show that chemokine-triggered lymphocyte adhesiveness involves a previously unrecognized extension step that primes LFA-1 for ligand binding and firm adhesion.
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Affiliation(s)
- Revital Shamri
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
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39
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Mattila PE, Green CE, Schaff U, Simon SI, Walcheck B. Cytoskeletal interactions regulate inducible L-selectin clustering. Am J Physiol Cell Physiol 2005; 289:C323-32. [PMID: 15788481 DOI: 10.1152/ajpcell.00603.2004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
L-selectin (CD62L) amplifies neutrophil capture within the microvasculature at sites of inflammation. Activation by G protein-coupled stimuli or through ligation of L-selectin promotes clustering of L-selectin and serves to increase its adhesiveness, signaling, and colocalization with beta(2)-integrins. Currently, little is known about the molecular process regulating the lateral mobility of L-selectin. On neutrophil stimulation, a progressive change takes place in the organization of its plasma membrane, resulting in membrane domains that are characteristically enriched in glycosyl phosphatidylinositol (GPI)-anchored proteins and exclude the transmembrane protein CD45. Clustering of L-selectin, facilitated by E-selectin engagement or antibody cross-linking, resulted in its colocalization with GPI-anchored CD55, but not with CD45 or CD11c. Disrupting microfilaments in neutrophils or removing a conserved cationic motif in the cytoplasmic domain of L-selectin increased its mobility and membrane domain localization in the plasma membrane. In addition, the conserved element was critical for L-selectin-dependent tethering under shear flow. Our data indicate that L-selectin's lateral mobility is regulated by interactions with the actin cytoskeleton that in turn fortifies leukocyte tethering. We hypothesize that both membrane mobility and stabilization augment L-selectin's effector functions and are regulated by dynamic associations with membrane domains and the actin cytoskeleton.
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Affiliation(s)
- Polly E Mattila
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN 55108, USA
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40
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Hao S, August A. Actin depolymerization transduces the strength of B-cell receptor stimulation. Mol Biol Cell 2005; 16:2275-84. [PMID: 15728723 PMCID: PMC1087234 DOI: 10.1091/mbc.e04-10-0881] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Polymerization of the actin cytoskeleton has been found to be essential for B-cell activation. We show here, however, that stimulation of BCR induces a rapid global actin depolymerization in a BCR signal strength-dependent manner, followed by polarized actin repolymerization. Depolymerization of actin enhances and blocking actin depolymerization inhibits BCR signaling, leading to altered BCR and lipid raft clustering, ERK activation, and transcription factor activation. Furthermore actin depolymerization by itself induces altered lipid raft clustering and ERK activation, suggesting that F-actin may play a role in separating lipid rafts and in setting the threshold for cellular activation.
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Affiliation(s)
- Shengli Hao
- Immunology Research Laboratories, Department of Veterinary Science, The Pennsylvania State University, University Park, PA 16802, USA
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41
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Patcha V, Wigren J, Winberg ME, Rasmusson B, Li J, Särndahl E. Differential inside-out activation of beta2-integrins by leukotriene B4 and fMLP in human neutrophils. Exp Cell Res 2004; 300:308-19. [PMID: 15474996 DOI: 10.1016/j.yexcr.2004.07.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2004] [Revised: 06/24/2004] [Indexed: 11/25/2022]
Abstract
We have investigated how LTB4, an endogenous chemoattractant encountered early in the inflammatory process, and fMLP, a bacteria-derived chemotactic peptide emanating from the site of infection, mediate inside-out regulation of the beta2-integrin. The role of the two chemoattractants on beta2-integrin avidity was investigated by measuring their effect on beta2-integrin clustering and surface mobility, whereas their effect on beta2-integrin affinity was measured by the expression of a high affinity epitope, a ligand-binding domain on beta2-integrins, and by integrin binding to s-ICAM. We find that the two chemoattractants modulate the beta2-integrin differently. LTB4 induces an increase in integrin clustering and surface mobility, but only a modest increase in integrin affinity. fMLP evokes a large increase in beta2-integrin affinity as well as in clustering and mobility. Lipoxin, which acts as a stop signal for the functions mediated by pro-inflammatory agents, was used as a tool for further examining the inside-out mechanisms. While LTB4-induced integrin clustering and mobility were inhibited by lipoxin, only a minor inhibition of fMLP-induced beta2-integrin avidity and no inhibition of integrin affinity were detected. The different modes of the inside-out regulation of beta2-integrins suggest that distinct mechanisms are involved in the beta2-integrin modulation induced by various chemoattractants.
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Affiliation(s)
- Veronika Patcha
- Division of Cell Biology/IBK, Faculty of Health Sciences, Linköping University, SE-581 85 Linköping, Sweden
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42
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Gálvez BG, Genís L, Matías-Román S, Oblander SA, Tryggvason K, Apte SS, Arroyo AG. Membrane type 1-matrix metalloproteinase is regulated by chemokines monocyte-chemoattractant protein-1/ccl2 and interleukin-8/CXCL8 in endothelial cells during angiogenesis. J Biol Chem 2004; 280:1292-8. [PMID: 15516694 DOI: 10.1074/jbc.m408673200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We have investigated the putative role and regulation of membrane type 1-matrix metalloproteinase (MT1-MMP) in angiogenesis induced by inflammatory factors of the chemokine family. The absence of MT1-MMP from null mice or derived mouse lung endothelial cells or the blockade of its activity with inhibitory antibodies resulted in the specific decrease of in vivo and in vitro angiogenesis induced by CCL2 but not CXCL12. Similarly, CCL2- and CXCL8-induced tube formation by human endothelial cells (ECs) was highly dependent on MT1-MMP activity. CCL2 and CXCL8 significantly increased MT1-MMP surface expression, clustering, activity, and function in human ECs. Investigation of the signaling pathways involved in chemokine-induced MT1-MMP activity in ECs revealed that CCL2 and CXCL8 induced cortical actin polymerization and sustained activation of phosphatidylinositol 3-kinase (PI3K) and the small GTPase Rac. Inhibition of PI3K or actin polymerization impaired CCL2-induced MT1-MMP activity. Finally, dimerization of MT1-MMP was found to be enhanced by CCL2 in ECs in a PI3K- and actin polymerization-dependent manner. In summary, we identify MT1-MMP as a molecular target preferentially involved in angiogenesis mediated by CCL2 and CXCL8, but not CXCL12, and suggest that MT1-MMP dimerization might be an important mechanism of its regulation during angiogenesis.
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Affiliation(s)
- Beatriz G Gálvez
- Departamento de Investigación Básica, Centro Nacional de Investigaciones Cardiovasculares, Ronda de Poniente, 5, 28760-Tres Cantos, Spain
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Piccardoni P, Manarini S, Federico L, Bagoly Z, Pecce R, Martelli N, Piccoli A, Totani L, Cerletti C, Evangelista V. SRC-dependent outside-in signalling is a key step in the process of autoregulation of beta2 integrins in polymorphonuclear cells. Biochem J 2004; 380:57-65. [PMID: 14969582 PMCID: PMC1224154 DOI: 10.1042/bj20040151] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Accepted: 02/18/2004] [Indexed: 01/04/2023]
Abstract
In human PMN (polymorphonuclear cells), challenged by P-selectin, the beta2-integrin Mac-1 (macrophage antigen-1) promoted the activation of the SRC (cellular homologue of Rous sarcoma virus oncogenic protein) family members HCK (haematopoietic cell kinase) and LYN (an SRC family protein tyrosine kinase) and phosphorylation of a P-110 (110 kDa protein). SRC kinase activity in turn was necessary for macrophage antigen-1-mediated adhesion [Piccardoni, Sideri, Manarini, Piccoli, Martelli, de Gaetano, Cerletti and Evangelista (2001) Blood 98, 108-116]. This suggested that an SRC-dependent outside-in signalling strengthens the beta2-integrin interaction with the ligand. To support this hypothesis further, in the present study, we used the monoclonal antibody KIM127 or manganese to lock beta2 integrins in a high-affinity state, and homotypic PMN adhesion was analysed to monitor beta2-integrin adhesive function. KIM127 or manganese induced PMN homotypic adhesion and P-110 phosphorylation. Both these processes were abolished by blocking antibodies against the common beta2 chain, by a combination of antibodies against alphaL and alphaM or by inhibitors of SRC activity. Confocal microscopy showed that activation epitopes were expressed by beta2 integrins co-localized with patches of F-actin at the adhesion sites. Blockade of SRC kinases or of actin polymerization prevented clustering of activated integrins as well as F-actin accumulation. FACS analysis showed that SRC inhibitors modified neither basal nor manganese-induced KIM127 binding. An SRC-dependent outside-in signalling initiated by beta2 integrins was also required for adhesion triggered by interleukin-8. These results confirm the hypothesis that an SRC-dependent outside-in signalling triggered by high affinity and ligand binding is necessary to stabilize beta2-integrin-mediated adhesion. Allowing clustering of activated integrins, SRC might link the high-affinity with the high-avidity state. Proline-rich tyrosine kinase-2 appears to be involved in this process.
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Affiliation(s)
- Paola Piccardoni
- Laboratory of Vascular Biology and Pharmacology, Consorzio Mario Negri Sud, Via Nazionale 1, 66030, Santa Maria Imbaro, Italy
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Ni N, Kevil CG, Bullard DC, Kucik DF. Avidity modulation activates adhesion under flow and requires cooperativity among adhesion receptors. Biophys J 2004; 85:4122-33. [PMID: 14645099 PMCID: PMC1303711 DOI: 10.1016/s0006-3495(03)74824-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
An early step in activation of leukocyte adhesion is a release of integrins from cytoskeletal constraints on their diffusion, leading to rearrangement and, consequently, increased avidity. Static adhesion assays using purified ligand as a substrate have demonstrated that very low doses of cytochalasin D disconnect beta2-integrins from their cytoskeletal links, allowing rearrangement and activating adhesion. The adhesion process in blood vessels is poorly simulated by these assays, however, for two reasons: leukocyte adhesion to endothelium 1), occurs in the presence of blood flow and 2), involves the simultaneous interactions of multiple sets of adhesion molecules. We investigated the effect of cytochalasin D, at concentrations that increase integrin diffusion but do not alter leukocyte shape and surface features, on adhesion of leukocytes to endothelial cells under flow. Cytochalasin D increased the number of rolling cells, the number of firmly adherent cells, and the duration of both rolling and firm adhesion. These effects required endothelial cell expression of ICAM-1, the ligand for leukocyte beta2-integrins. The beta2-integrin-ICAM-1 interaction alone was not sufficient, however. Experiments using purified substrates demonstrated that avidity effects on activation of adhesion under flow require functional cooperativity between integrins and other adhesion receptors.
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Affiliation(s)
- Na Ni
- Department of Genomics and Pathobiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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45
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Sehnert B, Cavcic A, Böhm B, Kalden JR, Nandakumar KS, Holmdahl R, Burkhardt H. Antileukoproteinase: Modulation of neutrophil function and therapeutic effects on anti-type II collagen antibody-induced arthritis. ACTA ACUST UNITED AC 2004; 50:2347-59. [PMID: 15248236 DOI: 10.1002/art.20339] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Antileukoproteinase (ALP) is a physiologic inhibitor of granulocytic serine proteases. The present study was undertaken to investigate its therapeutic benefit in an antibody-transfer model of erosive polyarthritis and to elucidate its potential to interfere with immune complex-dependent inflammatory pathways. METHODS Arthritis development was induced in male (BALB/c x B10.Q)F(1) mice by intravenous injection of two monoclonal antibodies specific for type II collagen and was quantified by clinical scoring and histopathology. Arthritis severity was assessed in a cohort of mice under systemic treatment with recombinant human ALP (daily doses of 0.1 mg for 5 days starting immediately after disease induction) in comparison with untreated controls. Concomitantly, functional assays (phagocytosis, oxidative burst, fluorescence-activated cell sorting analysis of integrin expression) were performed on neutrophils upon in vitro stimulation by IgG-coated latex beads. RESULTS ALP treatment reduced arthritis incidence and severity and had a protective effect against cartilage and bone erosion. ALP inhibited the conversion of the leukocyte beta2 integrins into an active conformation upon Fc receptor stimulation of granulocytes. ALP bound to the actin-bundling protein L-plastin and down-modulated filamentous actin assembly in response to stimulation with IgG-coated latex beads in granulocytes. ALP exerted additional inhibitory effects on neutrophil functions associated with cytoskeletal reorganization, such as phagocytosis and oxidative burst. CONCLUSION In addition to its antiprotease activity, ALP exerts a variety of blocking effects on neutrophil functions, probably due to modulation of cytoskeletal changes, that may contribute to this inhibitor's antiarthritis potential and qualify it as a multifunctional regulator of inflammatory responses.
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Affiliation(s)
- Bettina Sehnert
- Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany
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46
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Vicente-Manzanares M, Sánchez-Madrid F. Role of the cytoskeleton during leukocyte responses. Nat Rev Immunol 2004; 4:110-22. [PMID: 15040584 DOI: 10.1038/nri1268] [Citation(s) in RCA: 272] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cytoskeleton is a cellular network of structural, adaptor and signalling molecules that regulates most cellular functions that are related to the immune response, including migration, extravasation, antien recognition, activation and phagocytosis by different subsets of leukocytes. Recently, a large number of regulatory elements and structural constituents of the leukocyte cytoskeleton have been identified. In this review, we discuss the composition and regulation of the different cytoskeletal elements and their role in immune responses.
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Affiliation(s)
- Miguel Vicente-Manzanares
- Servicio de Inmunología, Hospital Universitario de la Princesa, c/Diego de León 62, 28006-Madrid, Spain
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47
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McDonald JF, Zheleznyak A, Frazier WA. Cholesterol-independent Interactions with CD47 Enhance αvβ3 Avidity. J Biol Chem 2004; 279:17301-11. [PMID: 14966135 DOI: 10.1074/jbc.m312782200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression in OV10 cells of either wild-type CD47 or its extracellular IgV domain linked to a glycosylphosphatidylinositol anchor-(IgV-GPI) enhanced ligand-induced alpha(v)beta(3) activation as detected by the binding of LIBS1 and LIBS6 mAbs. The amplitude of LIBS binding was greater with both CD47 and IgV-GPI expression, indicating an increase in the population of "activable" integrin molecules. Expression of either CD47 species also increased alpha(v)beta(3)-mediated adhesion to vitronectin, and to surfaces coated with the anti-beta(3) antibody AP3, because of enhanced clustering of alpha(v)beta(3) as confirmed by chemical cross-linking. Cholesterol depletion with methyl-beta-cyclodextrin did not prevent the increase in anti-LIBS binding, but reduced cell adhesion to vitronectin and AP3. However, cells expressing CD47 were partially insulated against this disruption, and IgV-GPI was even more effective. Both CD47 and IgV-GPI were found in cholesterol-rich rafts prepared in the absence of detergent, but only CD47 could recruit alpha(v)beta(3) and its associated signaling molecules to these domains. Thus CD47-alpha(v)beta(3) complexes in cholesterol-rich raft domains appear to engage in G(i)-dependent signaling whereas CD47-alpha(v)beta(3) interactions that lead to integrin clustering are also detergent resistant, but are insensitive to cholesterol depletion and do not require the transmembrane region of CD47.
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Affiliation(s)
- John F McDonald
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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48
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Marino JH, Cook P, Miller KS. Accurate and statistically verified quantification of relative mRNA abundances using SYBR Green I and real-time RT-PCR. J Immunol Methods 2004; 283:291-306. [PMID: 14659920 DOI: 10.1016/s0022-1759(03)00103-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Among the many methods currently available for quantifying mRNA transcript abundance, reverse transcription-polymerase chain reaction (RT-PCR) has proved to be the most sensitive. Recently, several protocols for real-time relative RT-PCR using the reporter dye SYBR Green I have appeared in the literature. In these methods, sample and control mRNA abundance is quantified relative to an internal reference RNA whose abundance is known not to change under the differing experimental conditions. We have developed new data analysis procedures for the two most promising of these methodologies and generated data appropriate to assess both the accuracy and precision of the two protocols. We demonstrate that while both methods produce results that are precise when 18S rRNA is used as an internal reference, only one of these methods produces consistently accurate results. We have used this latter system to show that mRNA abundances can be accurately measured and strongly correlate with cell surface protein and carbohydrate expression as assessed by flow cytometry under different conditions of B cell activation.
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Affiliation(s)
- Julie H Marino
- Faculty of Biological Sciences, The University of Tulsa, 600 S. College Avenue, Tulsa, OK 74104-3189, USA
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49
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Schön MP, Zollner TM, Boehncke WH. The molecular basis of lymphocyte recruitment to the skin: clues for pathogenesis and selective therapies of inflammatory disorders. J Invest Dermatol 2004; 121:951-62. [PMID: 14708592 DOI: 10.1046/j.1523-1747.2003.12563.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Spatial compartmentalization and tissue-selective localization of T lymphocytes to the skin are crucial for immune surveillance and the pathogenesis of various disorders including common inflammatory diseases such as atopic dermatitis or psoriasis, but also malignancies such as cutaneous T cell lymphomas. Cutaneous recruitment of lymphocytes is a highly complex process that involves extravasation, migration through the dermal connective tissue, and eventually, localization to the epidermis. An intertwined network of cytokines and chemokines provides the road signs for leukocyte migration, while various adhesion receptors orchestrate the dynamic events of cell-cell and cell-substrate interactions resulting in cutaneous localization of T cells. Selectively targeting the functions of molecules involved in this interplay promises exciting new therapeutic options for treating inflammatory skin disorders.
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Affiliation(s)
- Michael P Schön
- Department of Dermatology, Otto-von-Guericke-University, Magdeburg, Germany.
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50
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Alon R, Etzioni A. LAD-III, a novel group of leukocyte integrin activation deficiencies. Trends Immunol 2004; 24:561-6. [PMID: 14552841 DOI: 10.1016/j.it.2003.08.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To extravasate the bloodstream at specific targets, circulating immune cells must activate their integrins to undergo rapid in situ modulation of affinity or avidity for their endothelial ligands. This activation involves specialized sub-second G-protein signal transduction triggered by endothelium-displayed chemoattractants--primarily chemokines--and their cognate leukocyte-expressed G-protein-coupled receptors (GPCRs). Recently, we reported a rare autosomal-recessive leukocyte adhesion deficiency (LAD) syndrome associated with a defective ability of integrins to undergo GPCR-mediated stimulation at endothelial contacts. This LAD shows significant similarities to a group of integrin-activation syndromes reported in leukocytes and platelets. Here, the mechanisms by which GPCRs might regulate leukocyte and platelet integrins are outlined with respect to this new family of LAD cases. We propose to term this the LAD-III family.
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Affiliation(s)
- Ronen Alon
- Department of Immunology, The Weizmann Institute of Science, 76100 Rehovot, Israel.
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