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Abstract
T cell activation is initiated by the recognition of specific antigenic peptides and subsequently accomplished by complex signaling cascades. These aspects have been extensively studied for decades as pivotal factors in the establishment of adaptive immunity. However, how receptors or signaling molecules are organized in the resting state prior to encountering antigens has received less attention. Recent advancements in super-resolution microscopy techniques have revealed topographically controlled pre-formed organization of key molecules involved in antigen recognition and signal transduction on microvillar projections of T cells before activation and substantial effort has been dedicated to characterizing the topological structure of resting T cells over the past decade. This review will summarize our current understanding of how key surface receptors are pre-organized on the T-cell plasma membrane and discuss the potential role of these receptors, which are preassembled prior to ligand binding in the early activation events of T cells.
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Affiliation(s)
- Yunmin Jung
- Department of Nano-Biomedical Engineering, Advanced Science Institute, Yonsei University, Seoul, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science, Seoul, Republic of Korea
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2
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Barr VA, Piao J, Balagopalan L, McIntire KM, Schoenberg FP, Samelson LE. Heterogeneity of Signaling Complex Nanostructure in T Cells Activated Via the T Cell Antigen Receptor. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1503-1522. [PMID: 37488826 PMCID: PMC11230849 DOI: 10.1093/micmic/ozad072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 06/08/2023] [Accepted: 06/18/2023] [Indexed: 07/26/2023]
Abstract
Activation of the T cell antigen receptor (TCR) is a key step in initiating the adaptive immune response. Single-molecule localization techniques have been used to investigate the arrangement of proteins within the signaling complexes formed around activated TCRs, but a clear picture of nanoscale organization in stimulated T cells has not emerged. Here, we have improved the examination of T cell nanostructure by visualizing individual molecules of six different proteins in a single sample of activated Jurkat T cells using the multiplexed antibody-size limited direct stochastic optical reconstruction microscopy (madSTORM) technique. We formally define irregularly shaped regions of interest, compare areas where signaling complexes are concentrated with other areas, and improve the statistical analyses of the locations of molecules. We show that nanoscale organization of proteins is mainly confined to the areas with dense concentrations of TCR-based signaling complexes. However, randomly distributed molecules are also found in some areas containing concentrated signaling complexes. These results are consistent with the view that the proteins within signaling complexes are connected by numerous weak interactions, leading to flexible, dynamic, and mutable structures which produce large variations in the nanostructure found in activated T cells.
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Affiliation(s)
- Valarie A Barr
- Laboratory of Cellular & Molecular Biology, Building 37 Room 2066, 37 Convent Drive, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892-4256, USA
| | - Juan Piao
- Department of Statistics, University of California at Los Angeles, 8965 Math Sciences Building, Los Angeles, CA 90095-1554, USA
| | - Lakshmi Balagopalan
- Laboratory of Cellular & Molecular Biology, Building 37 Room 2066, 37 Convent Drive, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892-4256, USA
| | - Katherine M McIntire
- Laboratory of Cellular & Molecular Biology, Building 37 Room 2066, 37 Convent Drive, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892-4256, USA
| | - Frederic P Schoenberg
- Department of Statistics, University of California at Los Angeles, 8965 Math Sciences Building, Los Angeles, CA 90095-1554, USA
| | - Lawrence E Samelson
- Laboratory of Cellular & Molecular Biology, Building 37 Room 2066, 37 Convent Drive, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892-4256, USA
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3
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Volkov DV, Stepanova VM, Rubtsov YP, Stepanov AV, Gabibov AG. Protein Tyrosine Phosphatase CD45 As an Immunity Regulator and a Potential Effector of CAR-T therapy. Acta Naturae 2023; 15:17-26. [PMID: 37908772 PMCID: PMC10615191 DOI: 10.32607/actanaturae.25438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 09/12/2023] [Indexed: 11/02/2023] Open
Abstract
The leukocyte common antigen CD45 is a receptor tyrosine phosphatase and one of the most prevalent antigens found on the surface of blood cells. CD45 plays a crucial role in the initial stages of signal transmission from receptors of various immune cell types. Immunodeficiency, autoimmune disorders, and oncological diseases are frequently caused by gene expression disorders and imbalances in CD45 isoforms. Despite extensive research into the structure and functions of CD45, the molecular mechanisms behind its role in transmitting signals from T-cell receptors and chimeric antigen receptors remain not fully understood. It is of utmost importance to comprehend the structural features of CD45 and its function in regulating immune system cell activation to study oncological diseases and the impact of CD45 on lymphocytes and T cells modified by chimeric antigen receptors.
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Affiliation(s)
- D. V. Volkov
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russian Federation
| | - V. M. Stepanova
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russian Federation
| | - Y. P. Rubtsov
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russian Federation
| | - A. V. Stepanov
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russian Federation
| | - A. G. Gabibov
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997 Russian Federation
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4
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Cassioli C, Patrussi L, Valitutti S, Baldari CT. Learning from TCR Signaling and Immunological Synapse Assembly to Build New Chimeric Antigen Receptors (CARs). Int J Mol Sci 2022; 23:14255. [PMID: 36430728 PMCID: PMC9694822 DOI: 10.3390/ijms232214255] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/10/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022] Open
Abstract
Chimeric antigen receptor (CAR) T cell immunotherapy is a revolutionary pillar in cancer treatment. Clinical experience has shown remarkable successes in the treatment of certain hematological malignancies but only limited efficacy against B cell chronic lymphocytic leukemia (CLL) and other cancer types, especially solid tumors. A wide range of engineering strategies have been employed to overcome the limitations of CAR T cell therapy. However, it has become increasingly clear that CARs have unique, unexpected features; hence, a deep understanding of how CARs signal and trigger the formation of a non-conventional immunological synapse (IS), the signaling platform required for T cell activation and execution of effector functions, would lead a shift from empirical testing to the rational design of new CAR constructs. Here, we review current knowledge of CARs, focusing on their structure, signaling and role in CAR T cell IS assembly. We, moreover, discuss the molecular features accounting for poor responses in CLL patients treated with anti-CD19 CAR T cells and propose CLL as a paradigm for diseases connected to IS dysfunctions that could significantly benefit from the development of novel CARs to generate a productive anti-tumor response.
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Affiliation(s)
- Chiara Cassioli
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Laura Patrussi
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Salvatore Valitutti
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1037, Centre de Recherche en Cancérologie de Toulouse (CRCT), Université de Toulouse III-Paul Sabatier, 31037 Toulouse, France
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse, 31059 Toulouse, France
| | - Cosima T. Baldari
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
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5
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Abstract
As the targets of chimeric antigen receptor (CAR)-T cells expand to a variety of cancers, autoimmune diseases, viral infections, and fibrosis, there is an increasing demand for identifying new antigens and designing new CARs that can be effectively activated. However, the rational selection of antigens and the design of CARs are limited by a lack of knowledge regarding the molecular mechanism by which CARs are activated by antigens. Here, we present data supporting a "size exclusion" model explaining how antigen signals are transmitted across the plasma membrane to activate the intracellular domains of CARs. In this model, antigen engagement with CAR results in a narrow intermembrane space that physically excludes CD45, a bulky phosphatase, out of the CAR zone, thus favoring CAR phosphorylation by kinases, which further triggers downstream pathways leading to T cell activation. Aligned with this model, increasing the size of CAR extracellular domains diminished CAR-T activation both in vitro and in a mouse lymphoma model; membrane-proximal epitopes activated CAR-Ts better than membrane-distal epitopes. Moreover, increasing the size of CD45 by antibody conjugation enhanced the activation of CARs that recognize membrane-distal epitopes. Consistently, CAR-Ts expressing CD45RABC, the larger isoform, were activated to a higher level than those expressing a smaller isoform CD45RO. Together, our work revealed that CAR-T activation depends on the size difference between the CAR-antigen pair and CD45; the size of CAR, antigen, and CD45 can thus be targets for tuning CAR-T activation.
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Affiliation(s)
- Qian Xiao
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA,Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA,Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Xinyan Zhang
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Liqun Tu
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA
| | - Jian Cao
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA,Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Christian S. Hinrichs
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA,Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Xiaolei Su
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA,Yale Cancer Center, Yale University, New Haven, CT, 06520, USA,Corresponding author: Xiaolei Su,
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6
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Margolis N, Moalem H, Meirson T, Galore-Haskel G, Markovits E, Baruch EN, Vizel B, Yeffet A, Kanterman-Rifman J, Debby A, Besser MJ, Schachter J, Markel G. Adenosine-deaminase-acting-on-RNA-1 facilitates T-cell migration toward human melanoma cells. Cancer Immunol Res 2022; 10:1127-1140. [PMID: 35731225 DOI: 10.1158/2326-6066.cir-21-0643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 01/10/2022] [Accepted: 06/14/2022] [Indexed: 11/16/2022]
Abstract
The effect of tumor/T-cell interactions on subsequent immune infiltration is undefined. Here we report that pre-exposure of melanoma cells to cognate T cells enhanced the chemotaxis of new T cells in vitro. The effect was HLA class I-restricted and IFNγ-dependent, as it was abolished by β2M-knockdown, MHC-blocking antibodies, JAK1 inhibitors, JAK1-silencing and IFNgR1-blocking antibodies. RNA-sequencing of 73 melanoma metastases showed a significant correlation between the interferon-inducible p150 isoform of adenosine-deaminase-acting-on-RNA-1 (ADAR1) enzyme and immune infiltration. Consistent with this, co-cultures of cognate melanoma/T-cell pairs led to IFNγ-dependent induction of ADAR1-p150 in the melanoma cells, as visualized in situ using dynamic cell blocks, in ovo using fertilized chick eggs, and in vitro with Western blots. ADAR1 staining and RNA-sequencing in patient-derived biopsies following immunotherapy showed a rise in ADAR1-p150 expression concurrently with CD8+ cell infiltration and clinical response. Silencing ADAR1-p150 abolished the IFNγ-driven enhanced T-cell migration, confirming its mechanistic role. Silencing and overexpression of the constitutive isoform of ADAR1, ADAR1-p110, decreased and increased T-cell migration, respectively. Chemokine arrays showed that ADAR1 controls the secretion of multiple chemokines from melanoma cells, probably through microRNA-mediated regulation. Chemokine receptor blockade eliminated the IFNγ-driven T-cell chemotaxis. We propose that the constitutive ADAR1 downregulation observed in melanoma contributes to immune exclusion, whereas antigen-specific T cells induce ADAR1-p150 by releasing IFNγ, which can drive T-cell infiltration.
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Affiliation(s)
| | - Hanna Moalem
- Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | | | | | | | - Erez N Baruch
- The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Bella Vizel
- Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | | | | | | | | | | | - Gal Markel
- Rabin Medical Center, Petah Tikva, Israel
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7
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The interplay between membrane topology and mechanical forces in regulating T cell receptor activity. Commun Biol 2022; 5:40. [PMID: 35017678 PMCID: PMC8752658 DOI: 10.1038/s42003-021-02995-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 12/21/2021] [Indexed: 12/20/2022] Open
Abstract
T cells are critically important for host defense against infections. T cell activation is specific because signal initiation requires T cell receptor (TCR) recognition of foreign antigen peptides presented by major histocompatibility complexes (pMHC) on antigen presenting cells (APCs). Recent advances reveal that the TCR acts as a mechanoreceptor, but it remains unclear how pMHC/TCR engagement generates mechanical forces that are converted to intracellular signals. Here we propose a TCR Bending Mechanosignal (TBM) model, in which local bending of the T cell membrane on the nanometer scale allows sustained contact of relatively small pMHC/TCR complexes interspersed among large surface receptors and adhesion molecules on the opposing surfaces of T cells and APCs. Localized T cell membrane bending is suggested to increase accessibility of TCR signaling domains to phosphorylation, facilitate selective recognition of agonists that form catch bonds, and reduce noise signals associated with slip bonds. Al-Aghbar et al propose a TCR bending mechanosignal model that demonstrates how local mechanical membrane bending may influence T cell receptor binding events and thus T-cell activation.
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8
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Shah K, Al-Haidari A, Sun J, Kazi JU. T cell receptor (TCR) signaling in health and disease. Signal Transduct Target Ther 2021; 6:412. [PMID: 34897277 PMCID: PMC8666445 DOI: 10.1038/s41392-021-00823-w] [Citation(s) in RCA: 133] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 12/18/2022] Open
Abstract
Interaction of the T cell receptor (TCR) with an MHC-antigenic peptide complex results in changes at the molecular and cellular levels in T cells. The outside environmental cues are translated into various signal transduction pathways within the cell, which mediate the activation of various genes with the help of specific transcription factors. These signaling networks propagate with the help of various effector enzymes, such as kinases, phosphatases, and phospholipases. Integration of these disparate signal transduction pathways is done with the help of adaptor proteins that are non-enzymatic in function and that serve as a scaffold for various protein-protein interactions. This process aids in connecting the proximal to distal signaling pathways, thereby contributing to the full activation of T cells. This review provides a comprehensive snapshot of the various molecules involved in regulating T cell receptor signaling, covering both enzymes and adaptors, and will discuss their role in human disease.
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Affiliation(s)
- Kinjal Shah
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
- Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Amr Al-Haidari
- Clinical Genetics and Pathology, Skåne University Hospital, Region Skåne, Lund, Sweden
- Clinical Sciences Department, Surgery Research Unit, Lund University, Malmö, Sweden
| | - Jianmin Sun
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
- Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund, Sweden
- NHC Key Laboratory of Metabolic Cardiovascular Diseases Research, Science and Technology center, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Julhash U Kazi
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden.
- Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund, Sweden.
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9
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Siokis A, Robert PA, Demetriou P, Kvalvaag A, Valvo S, Mayya V, Dustin ML, Meyer-Hermann M. Characterization of mechanisms positioning costimulatory complexes in immune synapses. iScience 2021; 24:103100. [PMID: 34622155 PMCID: PMC8479700 DOI: 10.1016/j.isci.2021.103100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/12/2021] [Accepted: 09/07/2021] [Indexed: 11/30/2022] Open
Abstract
Small immunoglobulin superfamily (sIGSF) adhesion complexes form a corolla of microdomains around an integrin ring and secretory core during immunological synapse (IS) formation. The corolla recruits and retains major costimulatory/checkpoint complexes, such as CD28, making forces that govern corolla formation of particular interest. Here, we investigated the mechanisms underlying molecular reorganization of CD2, an adhesion and costimulatory molecule of the sIGSF family during IS formation. Computer simulations showed passive distal exclusion of CD2 complexes under weak interactions with the ramified F-actin transport network. Attractive forces between CD2 and CD28 complexes relocate CD28 from the IS center to the corolla. Size-based sorting interactions with large glycocalyx components, such as CD45, or short-range CD2 self-attraction successfully explain the corolla 'petals.' This establishes a general simulation framework for complex pattern formation observed in cell-bilayer and cell-cell interfaces, and the suggestion of new therapeutic targets, where boosting or impairing characteristic pattern formation can be pivotal.
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Affiliation(s)
- Anastasios Siokis
- Department of Systems Immunology and Braunschweig Integrated Centre of Systems Biology, Helmholtz Centre for Infection Research, Braunschweig 38106, Germany
| | - Philippe A. Robert
- Department of Systems Immunology and Braunschweig Integrated Centre of Systems Biology, Helmholtz Centre for Infection Research, Braunschweig 38106, Germany
| | - Philippos Demetriou
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7FY, UK
| | - Audun Kvalvaag
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7FY, UK
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Salvatore Valvo
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7FY, UK
| | - Viveka Mayya
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7FY, UK
| | - Michael L. Dustin
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7FY, UK
| | - Michael Meyer-Hermann
- Department of Systems Immunology and Braunschweig Integrated Centre of Systems Biology, Helmholtz Centre for Infection Research, Braunschweig 38106, Germany
- Institute of Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig 38106, Germany
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10
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Wilhelm KB, Morita S, McAffee DB, Kim S, O'Dair MK, Groves JT. Height, but not binding epitope, affects the potency of synthetic TCR agonists. Biophys J 2021; 120:3869-3880. [PMID: 34453921 PMCID: PMC8511163 DOI: 10.1016/j.bpj.2021.08.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 12/27/2022] Open
Abstract
Under physiological conditions, peptide-major histocompatibility complex (pMHC) molecules can trigger T cell receptors (TCRs) as monovalent ligands that are sparsely distributed on the plasma membrane of an antigen-presenting cell. TCRs can also be triggered by artificial clustering, such as with pMHC tetramers or antibodies; however, these strategies circumvent many of the natural ligand discrimination mechanisms of the T cell and can elicit nonphysiological signaling activity. We have recently introduced a synthetic TCR agonist composed of an anti-TCRβ Fab′ antibody fragment covalently bound to a DNA oligonucleotide, which serves as a membrane anchor. This Fab′-DNA ligand efficiently triggers TCR as a monomer when membrane associated and exhibits a potency and activation profile resembling agonist pMHC. In this report, we explore the geometric requirements for efficient TCR triggering and cellular activation by Fab′-DNA ligands. We find that T cells are insensitive to the ligand binding epitope on the TCR complex but that length of the DNA tether is important. Increasing, the intermembrane distance spanned by Fab′-DNA:TCR complexes decreases TCR triggering efficiency and T cell activation potency, consistent with the kinetic-segregation model of TCR triggering. These results establish design parameters for constructing synthetic TCR agonists that are able to activate polyclonal T cell populations, such as T cells from a human patient, in a similar manner as the native pMHC ligand.
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Affiliation(s)
- Kiera B Wilhelm
- Department of Chemistry, University of California, Berkeley, California
| | - Shumpei Morita
- Department of Chemistry, University of California, Berkeley, California
| | - Darren B McAffee
- Department of Chemistry, University of California, Berkeley, California
| | - Sungi Kim
- Department of Chemistry, University of California, Berkeley, California
| | - Mark K O'Dair
- Department of Chemistry, University of California, Berkeley, California
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, California.
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11
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Lee HS, Kim J, Choi HG, Kim EK, Jun CD. Licoricidin Abrogates T-Cell Activation by Modulating PTPN1 Activity and Attenuates Atopic Dermatitis In Vivo. J Invest Dermatol 2021; 141:2490-2498.e6. [PMID: 33857487 DOI: 10.1016/j.jid.2021.02.759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 01/13/2021] [Accepted: 02/16/2021] [Indexed: 12/01/2022]
Abstract
Licoricidin, the fifth-highest fraction among the isolated 48 molecules from Glycyrrhiza uralensis extracts, has been known as an anti-inflammatory bioactive molecule; however, few studies have shown its inhibitory effect on T-cell activation and atopic dermatitis (AD). This study examined the therapeutic potential of licoricidin in AD by modulating T-cell activation with molecular mechanisms. Licoricidin attenuated the expression of IL-2 mRNA in stimulated T cells without cytotoxicity. Because tyrosine-protein phosphatase nonreceptor type 1 was predicted to interact physically with licoricidin in T cells in silico analysis, the results of tyrosine-protein phosphatase nonreceptor type 1 activity assay and phosphorylation study predicted that licoricidin might abrogate the activity of tyrosine-protein phosphatase nonreceptor type 1 during T-cell activation. Pretreatment with licoricidin controlled the dephosphorylation of Lck on TCR-mediated stimulation. Moreover, licoricidin alleviated the symptoms of dinitrochlorobenzene- and/or mite extract-induced AD, including ear thickness and serum IgE level. Microscopic analysis also showed the effects of licoricidin on the thickness of the dermis and epidermis and infiltration of immune cells. Furthermore, mRNA levels of proinflammatory cytokines were attenuated in the ear lesions of licoricidin-treated AD mice. Therefore, licoricidin has therapeutic potential for treating AD, and its underlying mechanism involves effective modulation of T-cell activation by controlling tyrosine-protein phosphatase nonreceptor type 1 to maintain Lck phosphorylation.
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Affiliation(s)
- Hyun-Su Lee
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea; Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Jooyoung Kim
- Office of Academic Affairs, Konkuk University, Chungju, Republic of Korea
| | - Hyun Gyu Choi
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Eun-Kyung Kim
- Department of Food Science and Nutrition, College of Health Sciences, Dong-A University, Busan, Republic of Korea; Center for Silver-targeted Biomaterials, Brain Busan 21 Plus program, Dong-A University, Busan, Republic of Korea.
| | - Chang-Duk Jun
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea; Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
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12
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Ben-Shmuel A, Sabag B, Biber G, Barda-Saad M. The Role of the Cytoskeleton in Regulating the Natural Killer Cell Immune Response in Health and Disease: From Signaling Dynamics to Function. Front Cell Dev Biol 2021; 9:609532. [PMID: 33598461 PMCID: PMC7882700 DOI: 10.3389/fcell.2021.609532] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/11/2021] [Indexed: 01/13/2023] Open
Abstract
Natural killer (NK) cells are innate lymphoid cells, which play key roles in elimination of virally infected and malignant cells. The balance between activating and inhibitory signals derived from NK surface receptors govern the NK cell immune response. The cytoskeleton facilitates most NK cell effector functions, such as motility, infiltration, conjugation with target cells, immunological synapse assembly, and cytotoxicity. Though many studies have characterized signaling pathways that promote actin reorganization in immune cells, it is not completely clear how particular cytoskeletal architectures at the immunological synapse promote effector functions, and how cytoskeletal dynamics impact downstream signaling pathways and activation. Moreover, pioneering studies employing advanced imaging techniques have only begun to uncover the architectural complexity dictating the NK cell activation threshold; it is becoming clear that a distinct organization of the cytoskeleton and signaling receptors at the NK immunological synapse plays a decisive role in activation and tolerance. Here, we review the roles of the actin cytoskeleton in NK cells. We focus on how actin dynamics impact cytolytic granule secretion, NK cell motility, and NK cell infiltration through tissues into inflammatory sites. We will also describe the additional cytoskeletal components, non-muscle Myosin II and microtubules that play pivotal roles in NK cell activity. Furthermore, special emphasis will be placed on the role of the cytoskeleton in assembly of immunological synapses, and how mutations or downregulation of cytoskeletal accessory proteins impact NK cell function in health and disease.
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Affiliation(s)
- Aviad Ben-Shmuel
- Laboratory of Molecular and Applied Immunology, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Batel Sabag
- Laboratory of Molecular and Applied Immunology, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Guy Biber
- Laboratory of Molecular and Applied Immunology, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Mira Barda-Saad
- Laboratory of Molecular and Applied Immunology, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
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13
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The Effect of Lipid Metabolism on CD4 + T Cells. Mediators Inflamm 2021; 2021:6634532. [PMID: 33505215 PMCID: PMC7806377 DOI: 10.1155/2021/6634532] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/22/2020] [Accepted: 12/28/2020] [Indexed: 11/17/2022] Open
Abstract
CD4+ T cells play a vital role in the adaptive immune system and are involved in the pathogenesis of many diseases, including cancer, autoimmune diseases, and chronic inflammation. As an important mechanism for energy storage, a lot of researches have clarified that metabolism imbalance interacts with immune disorder, and one leads to the other. Lipid metabolism has close relationship with CD4+ T cells. In this review, we discuss fatty acid, cholesterol, prostaglandin, and phospholipid metabolism in CD4+ T cell subsets. Fatty acid β-oxidation (FAO) is activated in Th17 cell to support the proinflammatory function. Cholesterol promotes Th1, Th2, and Treg cell differentiation. In addition to glucose metabolism, lipid metabolism is also very important for immunity. Here, it is highlighted that lipid metabolism regulates CD4+ T cell differentiation and function and is related to diseases.
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14
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Wu L, Wei Q, Brzostek J, Gascoigne NRJ. Signaling from T cell receptors (TCRs) and chimeric antigen receptors (CARs) on T cells. Cell Mol Immunol 2020; 17:600-612. [PMID: 32451454 DOI: 10.1038/s41423-020-0470-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/05/2020] [Indexed: 12/15/2022] Open
Abstract
T cells react to foreign or self-antigens through T cell receptor (TCR) signaling. Several decades of research have delineated the mechanism of TCR signal transduction and its impact on T cell performance. This knowledge provides the foundation for chimeric antigen receptor T cell (CAR-T cell) technology, by which T cells are redirected in a major histocompatibility complex-unrestricted manner. TCR and CAR signaling plays a critical role in determining the T cell state, including exhaustion and memory. Given its artificial nature, CARs might affect or rewire signaling differently than TCRs. A better understanding of CAR signal transduction would greatly facilitate improvements to CAR-T cell technology and advance its usefulness in clinical practice. Herein, we systematically review the knowns and unknowns of TCR and CAR signaling, from the contact of receptors and antigens, proximal signaling, immunological synapse formation, and late signaling outcomes. Signaling through different T cell subtypes and how signaling is translated into practice are also discussed.
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Affiliation(s)
- Ling Wu
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Qianru Wei
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Joanna Brzostek
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore. .,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore.
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15
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Lindner SE, Johnson SM, Brown CE, Wang LD. Chimeric antigen receptor signaling: Functional consequences and design implications. SCIENCE ADVANCES 2020; 6:eaaz3223. [PMID: 32637585 PMCID: PMC7314561 DOI: 10.1126/sciadv.aaz3223] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/10/2020] [Indexed: 05/27/2023]
Abstract
Chimeric antigen receptor (CAR) T cell therapy has transformed the care of refractory B cell malignancies and holds tremendous promise for many aggressive tumors. Despite overwhelming scientific, clinical, and public interest in this rapidly expanding field, fundamental inquiries into CAR T cell mechanistic functioning are still in their infancy. Because CAR T cells are manufactured from donor T lymphocytes, and because CARs incorporate well-characterized T cell signaling components, it has largely been assumed that CARs signal analogously to canonical T cell receptors (TCRs). However, recent studies demonstrate that many aspects of CAR signaling are unique, distinct from endogenous TCR signaling, and potentially even distinct among various CAR constructs. Thus, rigorous and comprehensive proteomic investigations are required for rational engineering of improved CARs. Here, we review what is known about proximal CAR signaling in T cells, compare it to conventional TCR signaling, and outline unmet challenges to improving CAR T cell therapy.
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Affiliation(s)
- S. E. Lindner
- Department of Immuno-Oncology, Beckham Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - S. M. Johnson
- Department of Immuno-Oncology, Beckham Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - C. E. Brown
- Department of Hematology and Hematopoietic Cell Transplantation, Beckham Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - L. D. Wang
- Department of Immuno-Oncology, Beckham Research Institute, City of Hope National Medical Center, Duarte, CA, USA
- Department of Pediatrics, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
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16
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Lin JJ, O'Donoghue GP, Wilhelm KB, Coyle MP, Low-Nam ST, Fay NC, Alfieri KN, Groves JT. Membrane Association Transforms an Inert Anti-TCRβ Fab' Ligand into a Potent T Cell Receptor Agonist. Biophys J 2020; 118:2879-2893. [PMID: 32407684 DOI: 10.1016/j.bpj.2020.04.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/09/2020] [Accepted: 04/13/2020] [Indexed: 12/27/2022] Open
Abstract
The natural peptide-major histocompatibility complex (pMHC) ligand for T cell receptors (TCRs) is inactive from solution yet capable of activating T cells at single-molecule levels when membrane-associated. This distinctive feature stems from the mechanism of TCR activation, which is thought to involve steric phosphatase exclusion as well as direct mechanical forces. It is possible to defeat this mechanism and activate T cells with solution ligands by cross-linking pMHC or using multivalent antibodies to TCR. However, these widely used strategies activate TCRs through a nonphysiological mechanism and can produce different activation profiles than natural, monovalent, membrane-associated pMHC. Here, we introduce a strictly monovalent anti-TCRβ H57 Fab' ligand that, when coupled to a supported lipid bilayer via DNA complementation, triggers TCRs and activates nuclear translocation of the transcription factor nuclear factor of activated T cells (NFAT) with a similar potency to pMHC in primary murine T cells. Importantly, like monovalent pMHC and unlike bivalent antibodies, monovalent Fab'-DNA triggers TCRs only when physically coupled to the membrane, and only around 100 individual Fab':TCR interactions are necessary to stimulate early T cell activation.
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Affiliation(s)
- Jenny J Lin
- Department of Chemistry, University of California, Berkeley, Berkeley, California
| | - Geoff P O'Donoghue
- Department of Chemistry, University of California, Berkeley, Berkeley, California.
| | - Kiera B Wilhelm
- Department of Chemistry, University of California, Berkeley, Berkeley, California
| | - Michael P Coyle
- Department of Chemistry, University of California, Berkeley, Berkeley, California.
| | - Shalini T Low-Nam
- Department of Chemistry, University of California, Berkeley, Berkeley, California
| | - Nicole C Fay
- Department of Molecular and Cellular Biology, University of California, Berkeley, Berkeley, California
| | - Katherine N Alfieri
- Department of Chemistry, University of California, Berkeley, Berkeley, California
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, California.
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17
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Tromp AT, van Strijp JAG. Studying Staphylococcal Leukocidins: A Challenging Endeavor. Front Microbiol 2020; 11:611. [PMID: 32351474 PMCID: PMC7174503 DOI: 10.3389/fmicb.2020.00611] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 03/19/2020] [Indexed: 01/01/2023] Open
Abstract
Staphylococcus aureus is a well-known colonizer of the human skin and nose, but also a human pathogen that causes a wide spectrum of diseases. It is well established that S. aureus secretes an arsenal of virulence factors that have evolved to circumvent the human immune system. A major group of S. aureus virulence factors is the bi-component β-barrel pore-forming toxins, also known as leukocidins. These pore-forming toxins target specific cells of the innate and adaptive immune system by interacting with specific receptors expressed on the cell membrane. Even though still heavily debated, clinical and epidemiological studies suggest the involvement of one of the bi-component toxin, Panton-Valentine Leukocidin (PVL), as an important factor contributing to the epidemic spread and increased virulence of CA-MRSA strains. However, the host- and cell-specificity of PVL and other leukocidins, and the lack of adequate in vivo models, fuels the controversy and impairs the appropriate assessment of their role in S. aureus pathophysiology. Currently, the mechanisms of pore-formation and the contribution of PVL and other leukocidins to S. aureus pathophysiology are incompletely understood. This review summarizes our current understanding of leukocidin pore-formation, knowledge gaps, and highlights recent findings identifying novel host-factors involved in the toxin-host interface. As a result, this review furthers emphasizes the complexity behind S. aureus leukocidin cytotoxicity and the challenges associated in the quest to study and understand these major virulence factors.
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Affiliation(s)
- Angelino T Tromp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
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18
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Regulation of cell adhesion: a collaborative effort of integrins, their ligands, cytoplasmic actors, and phosphorylation. Q Rev Biophys 2019; 52:e10. [PMID: 31709962 DOI: 10.1017/s0033583519000088] [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]
Abstract
Integrins are large heterodimeric type 1 membrane proteins expressed in all nucleated mammalian cells. Eighteen α-chains and eight β-chains can combine to form 24 different integrins. They are cell adhesion proteins, which bind to a large variety of cellular and extracellular ligands. Integrins are required for cell migration, hemostasis, translocation of cells out from the blood stream and further movement into tissues, but also for the immune response and tissue morphogenesis. Importantly, integrins are not usually active as such, but need activation to become adhesive. Integrins are activated by outside-in activation through integrin ligand binding, or by inside-out activation through intracellular signaling. An important question is how integrin activity is regulated, and this topic has recently drawn much attention. Changes in integrin affinity for ligand binding are due to allosteric structural alterations, but equally important are avidity changes due to integrin clustering in the plane of the plasma membrane. Recent studies have partially solved how integrin cell surface structures change during activation. The integrin cytoplasmic domains are relatively short, but by interacting with a variety of cytoplasmic proteins in a regulated manner, the integrins acquire a number of properties important not only for cell adhesion and movement, but also for cellular signaling. Recent work has shown that specific integrin phosphorylations play pivotal roles in the regulation of integrin activity. Our purpose in this review is to integrate the present knowledge to enable an understanding of how cell adhesion is dynamically regulated.
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19
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Lu JG, Ji P, French SW. The Major Histocompatibility Complex Class II-CD4 Immunologic Synapse in Alcoholic Hepatitis and Autoimmune Liver Pathology: The Role of Aberrant Major Histocompatibility Complex Class II in Hepatocytes. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 190:25-32. [PMID: 31669415 DOI: 10.1016/j.ajpath.2019.09.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 08/27/2019] [Accepted: 09/24/2019] [Indexed: 12/12/2022]
Abstract
The major histocompatibility complex class II (MHC II)-CD4 immunologic synapse is classically described between the T-cell receptor of CD4-positive lymphocytes and MHC II on antigen-presenting cells. This interaction and others between surrounding costimulatory and checkpoint molecules promote differentiation of naïve CD4 T lymphocytes into helper T cells subtypes, including types 1, 2, and 17 helper T cells, that have more tailored immunologic responses. Although MHC II is mainly produced by professional antigen-presenting cells, it can be aberrantly produced by other cell types, including hepatocytes in various liver pathologies, such as autoimmune hepatitis and alcoholic hepatitis. This can lead to direct targeting of hepatocytes by CD4-positive lymphocytes, which form an immunologic synapse with the hepatocyte. The lymphocytes internalize the MHC II-CD4 complexes in a phagocytosis-like mechanism and in the process eat the hepatocyte piece by piece. We review the evidence for this mechanism and the role of these autoimmune responses in various liver diseases, including alcoholic hepatitis, autoimmune hepatitis, and primary biliary cirrhosis. The role of aberrant MHC II in malignancy, including hepatocellular carcinoma, is also reviewed. Further understanding of this mechanism can lead to better understanding of the immune mechanisms involved in these liver pathologies, with potential diagnostic and therapeutic applications.
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Affiliation(s)
- Jiajie G Lu
- Department of Pathology, Harbor-UCLA Medical Center, Torrance, California.
| | - Ping Ji
- Department of Pathology, Harbor-UCLA Medical Center, Torrance, California
| | - Samuel W French
- Department of Pathology, Harbor-UCLA Medical Center, Torrance, California
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20
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Mognetti BM, Cicuta P, Di Michele L. Programmable interactions with biomimetic DNA linkers at fluid membranes and interfaces. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:116601. [PMID: 31370052 DOI: 10.1088/1361-6633/ab37ca] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
At the heart of the structured architecture and complex dynamics of biological systems are specific and timely interactions operated by biomolecules. In many instances, biomolecular agents are spatially confined to flexible lipid membranes where, among other functions, they control cell adhesion, motility and tissue formation. Besides being central to several biological processes, multivalent interactions mediated by reactive linkers confined to deformable substrates underpin the design of synthetic-biological platforms and advanced biomimetic materials. Here we review recent advances on the experimental study and theoretical modelling of a heterogeneous class of biomimetic systems in which synthetic linkers mediate multivalent interactions between fluid and deformable colloidal units, including lipid vesicles and emulsion droplets. Linkers are often prepared from synthetic DNA nanostructures, enabling full programmability of the thermodynamic and kinetic properties of their mutual interactions. The coupling of the statistical effects of multivalent interactions with substrate fluidity and deformability gives rise to a rich emerging phenomenology that, in the context of self-assembled soft materials, has been shown to produce exotic phase behaviour, stimuli-responsiveness, and kinetic programmability of the self-assembly process. Applications to (synthetic) biology will also be reviewed.
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Affiliation(s)
- Bortolo Matteo Mognetti
- Université libre de Bruxelles (ULB), Interdisciplinary Center for Nonlinear Phenomena and Complex Systems, Campus Plaine, CP 231, Blvd. du Triomphe, B-1050 Brussels, Belgium
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21
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Cassioli C, Baldari CT. A Ciliary View of the Immunological Synapse. Cells 2019; 8:E789. [PMID: 31362462 PMCID: PMC6721628 DOI: 10.3390/cells8080789] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/15/2019] [Accepted: 07/25/2019] [Indexed: 12/28/2022] Open
Abstract
The primary cilium has gone from being a vestigial organelle to a crucial signaling hub of growing interest given the association between a group of human disorders, collectively known as ciliopathies, and defects in its structure or function. In recent years many ciliogenesis proteins have been observed at extraciliary sites in cells and likely perform cilium-independent functions ranging from regulation of the cytoskeleton to vesicular trafficking. Perhaps the most striking example is the non-ciliated T lymphocyte, in which components of the ciliary machinery are repurposed for the assembly and function of the immunological synapse even in the absence of a primary cilium. Furthermore, the specialization traits described at the immunological synapse are similar to those seen in the primary cilium. Here, we review common regulators and features shared by the immunological synapse and the primary cilium that document the remarkable homology between these structures.
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Affiliation(s)
- Chiara Cassioli
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Cosima T Baldari
- Department of Life Sciences, University of Siena, 53100 Siena, Italy.
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22
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Abstract
T cells effectively explore the tissue in search for antigens. When activated, they dedicate a big amount of energy and resources to arrange a complex structure called immunological synapse (IS), containing a particular distribution of molecules defined as supramolecular activation clusters (SMACs), and become polarized toward the target cell in a manner that channels the information specifically. This arrangement is symmetrical and requires the polarization of the MTOC and the Golgi to be operational, especially for the proper delivery of lytic granules and the recycling of molecules three dimensionally segregated at the clustered interface. Alternatively, after the productive encounter, T cells need to rearrange again to newly navigate through the tissue, changing back to a motile state called immunological kinapse (IK). In this IK state, the MTOC and the Golgi apparatus are repositioned and recruited at the back of the T cell to facilitate motility, while the established symmetry of the elements of the SMACs is broken and distributed in a different pattern. Both states, IS and IK, are interchangeable and are mainly orchestrated by the MTOC/Golgi complex, being critical for an effective immune response.
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23
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Jenkins E, Santos AM, O'Brien-Ball C, Felce JH, Wilcock MJ, Hatherley D, Dustin ML, Davis SJ, Eggeling C, Sezgin E. Reconstitution of immune cell interactions in free-standing membranes. J Cell Sci 2018; 132:jcs219709. [PMID: 30209137 PMCID: PMC6398472 DOI: 10.1242/jcs.219709] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 09/04/2018] [Indexed: 12/28/2022] Open
Abstract
The spatiotemporal regulation of signalling proteins at the contacts formed between immune cells and their targets determines how and when immune responses begin and end. Therapeutic control of immune responses therefore relies on thorough elucidation of the molecular processes occurring at these interfaces. However, the detailed investigation of each component's contribution to the formation and regulation of the contact is hampered by the complexities of cell composition and architecture. Moreover, the transient nature of these interactions creates additional challenges, especially in the use of advanced imaging technology. One approach that circumvents these problems is to establish in vitro systems that faithfully mimic immune cell interactions, but allow complexity to be 'dialled-in' as needed. Here, we present an in vitro system that makes use of synthetic vesicles that mimic important aspects of immune cell surfaces. Using this system, we began to explore the spatial distribution of signalling molecules (receptors, kinases and phosphatases) and how this changes during the initiation of signalling. The GUV/cell system presented here is expected to be widely applicable.
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Affiliation(s)
- Edward Jenkins
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Ana Mafalda Santos
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Caitlin O'Brien-Ball
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - James H Felce
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, OX3 7FY, UK
| | - Martin J Wilcock
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Deborah Hatherley
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, OX3 7FY, UK
| | - Simon J Davis
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
- Institute of Applied Optics Friedrich-Schiller-University Jena, Max-Wien Platz 4, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
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24
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Tang L, Zheng Y, Melo MB, Mabardi L, Castaño AP, Xie YQ, Li N, Kudchodkar SB, Wong HC, Jeng EK, Maus MV, Irvine DJ. Enhancing T cell therapy through TCR-signaling-responsive nanoparticle drug delivery. Nat Biotechnol 2018; 36:707-716. [PMID: 29985479 PMCID: PMC6078803 DOI: 10.1038/nbt.4181] [Citation(s) in RCA: 406] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 06/07/2018] [Indexed: 12/24/2022]
Abstract
Adoptive cell therapy (ACT) with antigen-specific T cells has shown remarkable clinical success, but approaches to safely and effectively augment T cell function, especially in solid tumors, remain of great interest. Here we describe a strategy to “backpack” large quantities of supporting protein drugs on T cells using protein nanogels (NGs) that selectively release these cargos in response to T cell receptor (TCR) activation. We design cell surface-conjugated NGs that respond to an increase in T cell surface reduction potential upon antigen recognition, limiting drug release to sites of antigen encounter such as the tumor microenvironment. Using NGs carrying an IL-15 superagonist complex, we demonstrate that relative to systemic administration of free cytokines, NG delivery selectively expands T cells 16-fold in tumors, and allows at least 8-fold higher doses of cytokine to be administered without toxicity. The improved therapeutic window enables substantially increased tumor clearance by murine T cell and human CAR-T cell therapy in vivo.
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Affiliation(s)
- Li Tang
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA.,Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Yiran Zheng
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Mariane Bandeira Melo
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Llian Mabardi
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA
| | - Ana P Castaño
- Cellular Immunotherapy Program, Massachusetts General Hospital (MGH) Cancer Center, Charlestown, Massachusetts, USA
| | - Yu-Qing Xie
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Na Li
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | | | - Hing C Wong
- Altor BioScience Corporation, Miramar, Florida, USA
| | - Emily K Jeng
- Altor BioScience Corporation, Miramar, Florida, USA
| | - Marcela V Maus
- Cellular Immunotherapy Program, Massachusetts General Hospital (MGH) Cancer Center, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Darrell J Irvine
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA.,Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
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25
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CD45 in human physiology and clinical medicine. Immunol Lett 2018; 196:22-32. [PMID: 29366662 DOI: 10.1016/j.imlet.2018.01.009] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 01/20/2023]
Abstract
CD45 is an evolutionary highly conserved receptor protein tyrosine phosphatase exclusively expressed on all nucleated cells of the hematopoietic system. It is characterized by the expression of several isoforms, specific to a certain cell type and the developmental or activation status of the cell. CD45 is one of the key players in the initiation of T cell receptor signaling by controlling the activation of the Src family protein-tyrosine kinases Lck and Fyn. CD45 deficiency results in T- and B-lymphocyte dysfunction in the form of severe combined immune deficiency. It also plays a significant role in autoimmune diseases and cancer as well as in infectious diseases including fungal infections. The knowledge collected on CD45 biology is rather vast, but it remains unclear whether all findings in rodent immune cells also apply to human CD45. This review focuses on human CD45 expression and function and provides an overview on its ligands and role in human pathology.
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26
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In vitro reconstitution of T cell receptor-mediated segregation of the CD45 phosphatase. Proc Natl Acad Sci U S A 2017; 114:E9338-E9345. [PMID: 29042512 PMCID: PMC5676914 DOI: 10.1073/pnas.1710358114] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
T cell signaling initiates upon the binding of peptide-loaded MHC (pMHC) on an antigen-presenting cell to the T cell receptor (TCR) on a T cell. TCR phosphorylation in response to pMHC binding is accompanied by segregation of the transmembrane phosphatase CD45 away from TCR-pMHC complexes. The kinetic segregation hypothesis proposes that CD45 exclusion shifts the local kinase-phosphatase balance to favor TCR phosphorylation. Spatial partitioning may arise from the size difference between the large CD45 extracellular domain and the smaller TCR-pMHC complex, although parsing potential contributions of extracellular protein size, actin activity, and lipid domains is difficult in living cells. Here, we reconstitute segregation of CD45 from bound receptor-ligand pairs using purified proteins on model membranes. Using a model receptor-ligand pair (FRB-FKBP), we first test physical and computational predictions for protein organization at membrane interfaces. We then show that the TCR-pMHC interaction causes partial exclusion of CD45. Comparing two developmentally regulated isoforms of CD45, the larger RABC variant is excluded more rapidly and efficiently (∼50%) than the smaller R0 isoform (∼20%), suggesting that CD45 isotypes could regulate signaling thresholds in different T cell subtypes. Similar to the sensitivity of T cell signaling, TCR-pMHC interactions with Kds of ≤15 µM were needed to exclude CD45. We further show that the coreceptor PD-1 with its ligand PD-L1, immunotherapy targets that inhibit T cell signaling, also exclude CD45. These results demonstrate that the binding energies of physiological receptor-ligand pairs on the T cell are sufficient to create spatial organization at membrane-membrane interfaces.
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27
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Dharan N, Farago O. Interplay between membrane elasticity and active cytoskeleton forces regulates the aggregation dynamics of the immunological synapse. SOFT MATTER 2017; 13:6938-6946. [PMID: 28825081 DOI: 10.1039/c7sm01064h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Adhesion between a T cell and an antigen presenting cell is achieved by TCR-pMHC and LFA1-ICAM1 protein complexes. These segregate to form a special pattern, known as the immunological synapse (IS), consisting of a central quasi-circular domain of TCR-pMHC bonds surrounded by a peripheral domain of LFA1-ICAM1 complexes. Insights gained from imaging studies had led to the conclusion that the formation of the central adhesion domain in the IS is driven by active (ATP-driven) mechanisms. Recent studies, however, suggested that passive (thermodynamic) mechanisms may also play an important role in this process. Here, we present a simple physical model, taking into account the membrane-mediated thermodynamic attraction between the TCR-pMHC bonds and the effective forces that they experience due to ATP-driven actin retrograde flow and transport by dynein motor proteins. Monte Carlo simulations of the model exhibit a good spatio-temporal agreement with the experimentally observed pattern evolution of the TCR-pMHC microclusters. The agreement is lost when one of the aggregation mechanisms is "muted", which helps to identify their respective roles in the process. We conclude that actin retrograde flow drives the centripetal motion of TCR-pMHC bonds, while the membrane-mediated interactions facilitate microcluster formation and growth. In the absence of dynein motors, the system evolves into a ring-shaped pattern, which highlights the role of dynein motors in the formation of the final concentric pattern. The interplay between the passive and active mechanisms regulates the rate of the accumulation process, which in the absence of one them proceeds either too quickly or slowly.
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Affiliation(s)
- Nadiv Dharan
- Department of Biomedical Engineering, Ben Gurion University of the Negev, Be'er Sheva 84105, Israel.
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Multi-color single-molecule tracking and subtrajectory analysis for quantification of spatiotemporal dynamics and kinetics upon T cell activation. Sci Rep 2017; 7:6994. [PMID: 28765585 PMCID: PMC5539329 DOI: 10.1038/s41598-017-06960-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/20/2017] [Indexed: 11/08/2022] Open
Abstract
The dynamic properties of molecules in living cells are attracting increasing interest. We propose a new method, moving subtrajectory analysis using single-molecule tracking, and demonstrate its utility in the spatiotemporal quantification of not only dynamics but also the kinetics of interactions using single-color images. Combining this technique with three-color simultaneous single-molecule imaging, we quantified the dynamics and kinetics of molecules in spatial relation to T cell receptor (TCR) microclusters, which trigger TCR signaling. CD3ε, a component of the TCR/CD3 complex, and CD45, a phosphatase positively and negatively regulating signaling, were each found in two mobility states: faster (associated) and slower (dissociated) states. Dynamics analysis suggests that the microclusters are loosely composed of heterogeneous nanoregions, possibly surrounded by a weak barrier. Kinetics analysis quantified the association and dissociation rates of interactions with the microclusters. The associations of both CD3ε and CD45 were single-step processes. In contrast, their dissociations were each composed of two components, indicating transient and stable associated states. Inside the microclusters, the association was accelerated, and the stable association was increased. Only CD45 showed acceleration of association at the microcluster boundary, suggesting specific affinity on the boundary. Thus, this method is an innovative and versatile tool for spatiotemporal quantification.
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Abstract
Phagocytosis refers to the active process that allows cells to take up large particulate material upon binding to surface receptors. The discovery of phagocytosis in 1883 by Elie Metchnikoff, leading to the concept that specialized cells are implicated in the defense against microbes, was one of the starting points of the field of immunology. After more than a century of research, phagocytosis is now appreciated to be a widely used process that enables the cellular uptake of a remarkable variety of particles, including bacteria, fungi, parasites, viruses, dead cells, and assorted debris and solid materials. Uptake of foreign particles is performed almost exclusively by specialized myeloid cells, commonly termed "professional phagocytes": neutrophils, monocytes, macrophages, and dendritic cells. Phagocytosis of microbes not only stops or at least restricts the spread of infection but also plays an important role in regulating the innate and adaptive immune responses. Activation of the myeloid cells upon phagocytosis leads to the secretion of cytokines and chemokines that convey signals to a variety of immune cells. Moreover, foreign antigens generated by the degradation of microbes following phagocytosis are loaded onto the major histocompatibility complex for presentation to specific T lymphocytes. However, phagocytosis is not restricted to professional myeloid phagocytes; an expanding diversity of cell types appear capable of engulfing apoptotic bodies and debris, playing a critical role in tissue remodeling and in the clearance of billions of effete cells every day.
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30
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In vitro tracking and intracellular protein distribution in immunology. Immunol Cell Biol 2017; 95:501-505. [PMID: 28392557 DOI: 10.1038/icb.2017.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 03/27/2017] [Accepted: 04/04/2017] [Indexed: 11/08/2022]
Abstract
New imaging techniques have enabled major advances in understanding how immune reactions are initiated, coordinated and controlled. Imaging methods, which were previously mostly descriptive and supplementary to more quantitative approaches, have now reached sufficient precision and throughput that they are becoming integral to almost all aspects of immunology research. Imaging methodologies that increase the resolution and sensitivity of detection, alongside an ever-expanding range of fluorescent reporters of molecular and cellular activity, and vastly improved analysis methods, have all facilitated this transformation. In this review, we will discuss how advances in imaging are changing the way we view immune activation and control using T cells as the model immune system. We will describe how imaging has transformed our knowledge of molecular and signalling events in T-cell activation, and the impact of these molecular events on the behaviour of T cells.
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Barr VA, Sherman E, Yi J, Akpan I, Rouquette-Jazdanian AK, Samelson LE. Development of nanoscale structure in LAT-based signaling complexes. J Cell Sci 2016; 129:4548-4562. [PMID: 27875277 PMCID: PMC5201021 DOI: 10.1242/jcs.194886] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 11/04/2016] [Indexed: 12/30/2022] Open
Abstract
The adapter molecule linker for activation of T cells (LAT) plays a crucial role in forming signaling complexes induced by stimulation of the T cell receptor (TCR). These multi-molecular complexes are dynamic structures that activate highly regulated signaling pathways. Previously, we have demonstrated nanoscale structure in LAT-based complexes where the adapter SLP-76 (also known as LCP2) localizes to the periphery of LAT clusters. In this study, we show that initially LAT and SLP-76 are randomly dispersed throughout the clusters that form upon TCR engagement. The segregation of LAT and SLP-76 develops near the end of the spreading process. The local concentration of LAT also increases at the same time. Both changes require TCR activation and an intact actin cytoskeleton. These results demonstrate that the nanoscale organization of LAT-based signaling complexes is dynamic and indicates that different kinds of LAT-based complexes appear at different times during T cell activation.
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Affiliation(s)
- Valarie A Barr
- Laboratory of Cellular and Molecular Biology, CCR, NCI, NIH, Bethesda, MD 20892, USA
| | - Eilon Sherman
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
| | - Jason Yi
- Laboratory of Cellular and Molecular Biology, CCR, NCI, NIH, Bethesda, MD 20892, USA
| | - Itoro Akpan
- Laboratory of Cellular and Molecular Biology, CCR, NCI, NIH, Bethesda, MD 20892, USA
| | | | - Lawrence E Samelson
- Laboratory of Cellular and Molecular Biology, CCR, NCI, NIH, Bethesda, MD 20892, USA
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32
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Goyette J, Gaus K. Mechanisms of protein nanoscale clustering. Curr Opin Cell Biol 2016; 44:86-92. [PMID: 27666166 DOI: 10.1016/j.ceb.2016.09.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/08/2016] [Indexed: 12/22/2022]
Abstract
Due to recent technical developments in microscopy, huge advances have been made in our understanding of the architecture of the cell membrane. It is now well appreciated that nanoscale clustering is a common feature of membrane proteins. Many of these clusters have been implicated in signal initiation and integration platforms. However, the mechanisms that mediate the dynamic nanoscale arrangement of membrane proteins are not fully understood and could involve lipid domains, electrostatic interactions between proteins and lipid, protein scaffolding as well as purely mechanical processes. In this review we summarise these mechanisms giving rise to dynamic nanoscale protein reorganisation in the plasma membrane with reference to recent examples of immune receptor clustering to illustrate general principles.
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Affiliation(s)
- Jesse Goyette
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney 2052, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney 2052, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia.
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33
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Freeman SA, Goyette J, Furuya W, Woods EC, Bertozzi CR, Bergmeier W, Hinz B, van der Merwe PA, Das R, Grinstein S. Integrins Form an Expanding Diffusional Barrier that Coordinates Phagocytosis. Cell 2016; 164:128-140. [PMID: 26771488 DOI: 10.1016/j.cell.2015.11.048] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 09/07/2015] [Accepted: 11/14/2015] [Indexed: 01/12/2023]
Abstract
Phagocytosis is initiated by lateral clustering of receptors, which in turn activates Src-family kinases (SFKs). Activation of SFKs requires depletion of tyrosine phosphatases from the area of particle engagement. We investigated how the major phosphatase CD45 is excluded from contact sites, using single-molecule tracking. The mobility of CD45 increased markedly upon engagement of Fcγ receptors. While individual CD45 molecules moved randomly, they were displaced from the advancing phagocytic cup by an expanding diffusional barrier. By micropatterning IgG, the ligand of Fcγ receptors, we found that the barrier extended well beyond the perimeter of the receptor-ligand engagement zone. Second messengers generated by Fcγ receptors activated integrins, which formed an actin-tethered diffusion barrier that excluded CD45. The expanding integrin wave facilitates the zippering of Fcγ receptors onto the target and integrates the information from sparse receptor-ligand complexes, coordinating the progression and ultimate closure of the phagocytic cup.
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Affiliation(s)
- Spencer A Freeman
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Jesse Goyette
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Wendy Furuya
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Elliot C Woods
- Department of Chemistry and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305-4401, USA
| | - Carolyn R Bertozzi
- Department of Chemistry and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305-4401, USA
| | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina, 120 Mason Farm Road, Chapel Hill, NC 27599-7260, USA
| | - Boris Hinz
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON M5S 3E2, Canada
| | | | - Raibatak Das
- Department of Integrative Biology, University of Colorado, Denver, CO 80217-3364, USA
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; Keenan Research Centre, St. Michael's Hospital, Toronto, ON M5S 1T8, Canada.
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34
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Braun M, Ress ML, Yoo YE, Scholz CJ, Eyrich M, Schlegel PG, Wölfl M. IL12-mediated sensitizing of T-cell receptor-dependent and -independent tumor cell killing. Oncoimmunology 2016; 5:e1188245. [PMID: 27622043 DOI: 10.1080/2162402x.2016.1188245] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/25/2016] [Accepted: 05/05/2016] [Indexed: 10/21/2022] Open
Abstract
Interleukin 12 (IL12) is a key inflammatory cytokine critically influencing Th1/Tc1-T-cell responses at the time of initial antigen encounter. Therefore, it may be exploited for cancer immunotherapy. Here, we investigated how IL12, and other inflammatory cytokines, shape effector functions of human T-cells. Using a defined culture system, we followed the gradual differentiation and function of antigen-specific CD8(+) T cells from their initial activation as naïve T cells through their expansion phase as early memory cells to full differentiation as clonally expanded effector T cells. The addition of IL12 8 days after the initial priming event initiated two mechanistically separate events: First, IL12 sensitized the T-cell receptor (TCR) for antigen-specific activation, leading to an approximately 10-fold increase in peptide sensitivity and, in consequence, enhanced tumor cell killing. Secondly, IL12 enabled TCR/HLA-independent activation and cytotoxicity: this "non-specific" effect was mediated by the NK cell receptor DNAM1 (CD226) and dependent on ligand expression of the target cells. This IL12 regulated, DNAM1-mediated killing is dependent on src-kinases as well as on PTPRC (CD45) activity. Thus, besides enhancing TCR-mediated activation, we here identified for the first time a second IL12 mediated mechanism leading to activation of a receptor-dependent killing pathway via DNAM1.
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Affiliation(s)
- Matthias Braun
- Children's Hospital, Pediatric Hematology, Oncology and Stem Cell Transplantation, University of Würzburg, Würzburg, Germany; Else-Kröner Forschungskolleg for Interdisciplinary Translational Immunology, School of Medicine, University of Würzburg, Würzburg, Germany
| | - Marie L Ress
- Children's Hospital, Pediatric Hematology, Oncology and Stem Cell Transplantation, University of Würzburg , Würzburg, Germany
| | - Young-Eun Yoo
- Children's Hospital, Pediatric Hematology, Oncology and Stem Cell Transplantation, University of Würzburg , Würzburg, Germany
| | - Claus J Scholz
- Core Unit Systems Medicine, University of Würzburg , Würzburg, Germany
| | - Matthias Eyrich
- Children's Hospital, Pediatric Hematology, Oncology and Stem Cell Transplantation, University of Würzburg , Würzburg, Germany
| | - Paul G Schlegel
- Children's Hospital, Pediatric Hematology, Oncology and Stem Cell Transplantation, University of Würzburg, Würzburg, Germany; Clinical Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
| | - Matthias Wölfl
- Children's Hospital, Pediatric Hematology, Oncology and Stem Cell Transplantation, University of Würzburg, Würzburg, Germany; Clinical Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
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35
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Chang VT, Fernandes RA, Ganzinger KA, Lee SF, Siebold C, McColl J, Jönsson P, Palayret M, Harlos K, Coles CH, Jones EY, Lui Y, Huang E, Gilbert RJC, Klenerman D, Aricescu AR, Davis SJ. Initiation of T cell signaling by CD45 segregation at 'close contacts'. Nat Immunol 2016; 17:574-582. [PMID: 26998761 PMCID: PMC4839504 DOI: 10.1038/ni.3392] [Citation(s) in RCA: 202] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/29/2015] [Indexed: 12/14/2022]
Abstract
It has been proposed that the local segregation of kinases and the tyrosine phosphatase CD45 underpins T cell antigen receptor (TCR) triggering, but how such segregation occurs and whether it can initiate signaling is unclear. Using structural and biophysical analysis, we show that the extracellular region of CD45 is rigid and extends beyond the distance spanned by TCR-ligand complexes, implying that sites of TCR-ligand engagement would sterically exclude CD45. We also show that the formation of 'close contacts', new structures characterized by spontaneous CD45 and kinase segregation at the submicron-scale, initiates signaling even when TCR ligands are absent. Our work reveals the structural basis for, and the potent signaling effects of, local CD45 and kinase segregation. TCR ligands have the potential to heighten signaling simply by holding receptors in close contacts.
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Affiliation(s)
- Veronica T Chang
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Ricardo A Fernandes
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, United Kingdom
| | | | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW
| | - Christian Siebold
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW
| | - Peter Jönsson
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW
| | - Matthieu Palayret
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW
| | - Karl Harlos
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN
| | - Charlotte H Coles
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN
| | - Yuan Lui
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Elizabeth Huang
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Robert J C Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW
| | - A Radu Aricescu
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN
| | - Simon J Davis
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, United Kingdom
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36
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Abstract
The molecular interactions underlying regulation of the immune response take place in a nanoscale gap between T cells and antigen-presenting cells, termed the immunological synapse. If these interactions are regulated appropriately, the host is defended against a wide range of pathogens and deranged host cells. If these interactions are disregulated, the host is susceptible to pathogens or tumor escape at one extreme and autoimmunity at the other. Strategies targeting the synapse have helped to establish immunotherapy as a mainstream element in cancer treatment. This Masters' primer will cover the basics of the immunological synapse and some of the applications to tumor immunology.
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Affiliation(s)
- Michael L Dustin
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, The University of Oxford, Headington, United Kingdom.
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37
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Kloc M, Kubiak JZ, Li XC, Ghobrial RM. The newly found functions of MTOC in immunological response. J Leukoc Biol 2013; 95:417-30. [DOI: 10.1189/jlb.0813468] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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38
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Huang J, Brameshuber M, Zeng X, Xie J, Li QJ, Chien YH, Valitutti S, Davis MM. A single peptide-major histocompatibility complex ligand triggers digital cytokine secretion in CD4(+) T cells. Immunity 2013; 39:846-57. [PMID: 24120362 PMCID: PMC3846396 DOI: 10.1016/j.immuni.2013.08.036] [Citation(s) in RCA: 262] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 08/02/2013] [Indexed: 11/26/2022]
Abstract
We have developed a single-molecule imaging technique that uses quantum-dot-labeled peptide-major histocompatibility complex (pMHC) ligands to study CD4(+) T cell functional sensitivity. We found that naive T cells, T cell blasts, and memory T cells could all be triggered by a single pMHC to secrete tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) cytokines with a rate of ∼1,000, ∼10,000, and ∼10,000 molecules/min, respectively, and that additional pMHCs did not augment secretion, indicating a digital response pattern. We also found that a single pMHC localized to the immunological synapse induced the slow formation of a long-lasting T cell receptor (TCR) cluster, consistent with a serial engagement mechanism. These data show that scaling up CD4(+) T cell cytokine responses involves increasingly efficient T cell recruitment rather than greater cytokine production per cell.
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Affiliation(s)
- Jun Huang
- Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, USA
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39
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Abstract
The recognition of peptide/MHC antigens by T-cells has continued to challenge the imagination of immunologists, biochemists, and cell biologists alike. This is at least in part because T-cell recognition connects a diversity of issues and transcends many scientific disciplines. A fundamental unsolved issue is how T-cells manage to detect even a single molecule of an agonist pMHC complex, which is vastly outnumbered by endogenous pMHCs, many of which involve the same MHC molecule. They do so although TCRs are cross-reactive and typically low in affinity when measured in isolation. Importantly, T-cell antigen recognition takes place within the contact zone between a T-cell and the antigen-presenting cell, termed the immunological synapse. This bimembrane structure sets the stage for the antigen-binding events and all subsequent molecular recognition events. There is increasing evidence that the molecular dynamics of receptor-ligand interactions are not only dependent on the intrinsic properties of the binding partners but also become transformed by cell biological parameters such as the geometrical constraints within the immune synapse, mechanical forces, and local molecular crowding. To appreciate the complete picture, we think a multidisciplinary approach is imperative, which includes genetics, biochemistry, and structure determination and also biophysical analyses and the latest molecular imaging techniques. Here, we review earlier pioneering work and also recent developments in the fascinating and interdisciplinary science of T-cell antigen recognition. In many ways, this work may present a useful "roadmap" for work in other systems of cell-cell recognition, which underlie many fundamental biological phenomenons of interest.
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40
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Abstract
Phosphorylation of the T cell antigen receptor (TCR) by the tyrosine kinase Lck is an essential step in the activation of T cells. Because Lck is constitutively active, spatial organization may regulate TCR signaling. Here we found that Lck distributions on the molecular level were controlled by the conformational states of Lck, with the open, active conformation inducing clustering and the closed, inactive conformation preventing clustering. In contrast, association with lipid domains and protein networks were not sufficient or necessary for Lck clustering. Conformation-driven Lck clustering was highly dynamic, so that TCR triggering resulted in Lck clusters that contained phosphorylated TCRs but excluded the phosphatase CD45. Our data suggest that Lck conformational states represent an intrinsic mechanism for the intermolecular organization of early T cell signaling.
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41
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Abstract
Leukocytes play a critical role in recognizing and responding to infection and cancer. Central to this function is an array of cell-surface receptors that lack sequence homology. Many of these receptors have in common the fact that their signaling involves phosphorylation of cytoplasmic domains by extrinsic tyrosine kinases. These non-catalytic tyrosine-phosphorylated receptors (NTRs) share a number of other features, including small size and optimal stimulation by surface-associated ligands. We argue here that NTRs are also likely to share the same kinetic-segregation triggering mechanism, which involves segregation of the engaged NTR from receptor tyrosine phosphatases with large ectodomains such as CD45 and CD148. NTRs signal through tyrosine-containing cytoplasmic motifs, which recruit distinct cytoplasmic signaling proteins when phosphorylated, transducing activatory or inhibitory signals. They have two features that make them uniquely well suited to their role in immune recognition of infection and cancer. Their modular structure enables the coupling of many rapidly evolving receptors with diverse ligand specificities to the same conserved signaling machinery. Their similarity in size and shared signaling machinery enables them to colocalize at cell-cell interfaces when they engage ligands, facilitating the integration of activatory and inhibitory signals from multiple receptors at the cell surface.
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Affiliation(s)
- Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, UK
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42
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Biophysical mechanism of T-cell receptor triggering in a reconstituted system. Nature 2012; 487:64-9. [PMID: 22763440 PMCID: PMC3393772 DOI: 10.1038/nature11220] [Citation(s) in RCA: 246] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 05/08/2012] [Indexed: 11/08/2022]
Abstract
A T cell-mediated immune response is initiated by the T cell receptor (TCR) interacting with peptide-bound MHC (pMHC) on an infected cell. The mechanism by which this interaction triggers intracellular phosphorylation of the TCR, which lacks a kinase domain, remains poorly understood. Here, we have introduced the TCR and associated signalling molecules into a nonimmune cell and reconstituted ligand-specific signalling when these cells are conjugated with antigen presenting cells. We show that signalling requires the differential segregation of a phosphatase and kinase in the plasma membrane. An artificial, chemically-controlled receptor system generates the same effect as TCR-pMHC, demonstrating that the binding energy of an extracellular protein-protein interaction can drive the spatial segregation of membrane proteins without a transmembrane conformational change. This general mechanism may extend to other receptors that rely on extrinsic kinases, including, as we demonstrate, chimaeric antigen receptors being developed for cancer immunotherapy.
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43
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Kumari S, Vardhana S, Cammer M, Curado S, Santos L, Sheetz MP, Dustin ML. T Lymphocyte Myosin IIA is Required for Maturation of the Immunological Synapse. Front Immunol 2012; 3:230. [PMID: 22912631 PMCID: PMC3421155 DOI: 10.3389/fimmu.2012.00230] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 07/14/2012] [Indexed: 01/13/2023] Open
Abstract
The role of non-muscle myosin IIA (heavy chain encoded by the non-muscle myosin heavy chain 9 gene, Myh9) in immunological synapse formation is controversial. We have addressed the role of myosin IIA heavy chain protein (MYH9) in mouse T cells responding to MHC-peptide complexes and ICAM-1 in supported planar bilayers - a model for immunological synapse maturation. We found that reduction of MYH9 expression levels using Myh9 siRNA in proliferating mouse CD4(+) AND T cell receptor (TCR) transgenic T cells resulted in increased spreading area, failure to assemble the central and peripheral supramolecular activation clusters (cSMAC and pSMAC), and increased motility. Surprisingly, TCR microcluster speed was reduced marginally, however TCR microclusters dissipated prior to forming a cSMAC. TCR microclusters formed in the Myh9 siRNA-treated T cells showed reduced phosphorylation of the Src family kinase (SFK) activation loop and displayed reduced cytoplasmic calcium ion (Ca(2+)) elevation. In addition, Myh9 siRNA-treated cells displayed reduced phosphorylation of the Cas-L substrate domain - a force-dependent SFK substrate - which was observed in control siRNA-treated cells in foci throughout the immunological synapse except the cSMAC. Cas-L exhibited TCR ligation-dependent induction of phosphorylation. These results provide further evidence that T cell activation is modulated by intrinsic force-generating systems and can be viewed as a mechanically responsive process influenced by MYH9.
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Affiliation(s)
- Sudha Kumari
- Helen and Martin Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew York, NY, USA
| | - Santosha Vardhana
- Helen and Martin Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew York, NY, USA
| | - Michael Cammer
- Helen and Martin Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew York, NY, USA
| | - Silvia Curado
- Helen and Martin Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew York, NY, USA
| | - Luis Santos
- Department of Biological Sciences, Columbia UniversityNew York, NY, USA
| | - Michael P. Sheetz
- Department of Biological Sciences, Columbia UniversityNew York, NY, USA
| | - Michael L. Dustin
- Helen and Martin Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew York, NY, USA
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44
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Rossy J, Williamson DJ, Gaus K. How does the kinase Lck phosphorylate the T cell receptor? Spatial organization as a regulatory mechanism. Front Immunol 2012; 3:167. [PMID: 22723799 PMCID: PMC3377954 DOI: 10.3389/fimmu.2012.00167] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 06/04/2012] [Indexed: 11/25/2022] Open
Abstract
T cell signaling begins with the ligation of the T cell antigen receptor (TCR) by a cognate peptide and the phosphorylation of the receptor’s immunoreceptor tyrosine-based activation motif domains by the kinase Lck. However, the canonical receptor model is insufficient to explain how the constitutively active kinase Lck can discriminate between non-ligated and ligated TCRs. Here, we discuss the factors that are thought to regulate the spatial distribution of the TCR and Lck, and therefore critically influence TCR signaling initiation.
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Affiliation(s)
- Jérémie Rossy
- Centre for Vascular Research, University of New South Wales, Sydney, NSW, Australia
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45
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Rhee I, Veillette A. Protein tyrosine phosphatases in lymphocyte activation and autoimmunity. Nat Immunol 2012; 13:439-47. [PMID: 22513334 DOI: 10.1038/ni.2246] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Lymphocyte activation must be tightly regulated to ensure sufficient immunity to pathogens and prevent autoimmunity. Protein tyrosine phosphatases (PTPs) serve critical roles in this regulation by controlling the functions of key receptors and intracellular signaling molecules in lymphocytes. In some cases, PTPs inhibit lymphocyte activation, whereas in others they promote it. Here we discuss recent progress in elucidating the roles and mechanisms of action of PTPs in lymphocyte activation. We also review the accumulating evidence that genetic alterations in PTPs are involved in human autoimmunity.
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Affiliation(s)
- Inmoo Rhee
- Laboratory of Molecular Oncology, Clinical Research Institute of Montréal, Montréal, Québec, Canada
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46
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Abstract
Immunological and neural synapses share properties such as the synaptic cleft, adhesion molecules, stability, and polarity. However, the mismatch in scale has limited the utility of these comparisons. The discovery of phosphatase micro-exclusion from signaling elements in immunological synapses and innate phagocytic synapses define a common functional unit at a common sub-micron scale across synapse types. Bundling of information from multiple antigen receptor microclusters by an immunological synapse has parallels to bundling of multiple synaptic inputs into a single axonal output by neurons, allowing integration and coincidence detection. Bonafide neuroimmune synapses control the inflammatory reflex. A better understanding of the shared mechanisms between immunological and neural synapses could aid in the development of new therapeutic modalities for immunological, neurological, and neuroimmunological disorders alike.
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Affiliation(s)
- Michael L Dustin
- The Helen L. and Martin S. Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York 10016, USA.
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Allard J, Dushek O, Coombs D, Anton van der Merwe P. Mechanical modulation of receptor-ligand interactions at cell-cell interfaces. Biophys J 2012; 102:1265-73. [PMID: 22455909 PMCID: PMC3309404 DOI: 10.1016/j.bpj.2012.02.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 02/01/2012] [Accepted: 02/07/2012] [Indexed: 01/13/2023] Open
Abstract
Cell surface receptors have been extensively studied because they initiate and regulate signal transduction cascades leading to a variety of functional cellular outcomes. An important class of immune receptors (e.g., T-cell antigen receptors) whose ligands are anchored to the surfaces of other cells remain poorly understood. The mechanism by which ligand binding initiates receptor phosphorylation, a process termed "receptor triggering", remains controversial. Recently, direct measurements of the (two-dimensional) receptor-ligand complex lifetimes at cell-cell interface were found to be smaller than (three-dimensional) lifetimes in solution but the underlying mechanism is unknown. At the cell-cell interface, the receptor-ligand complex spans a short intermembrane distance (15 nm) compared to long surface molecules (LSMs) whose ectodomains span >40 nm and these LSMs include phosphatases (e.g., CD45) that dephosphorylate the receptor. It has been proposed that size-based segregation of LSMs from a receptor-ligand complex is a mechanism of receptor triggering but it is unclear whether the mechanochemistry supports such small-scale segregation. Here we present a nanometer-scale mathematical model that couples membrane elasticity with the compressional stiffness and lateral mobility of LSMs. We find robust supradiffusive segregation of LSMs from a single receptor-ligand complex. The model predicts that LSM redistribution will result in a time-dependent tension on the complex leading to a decreased two-dimensional lifetime. Interestingly, the model predicts a nonlinear relationship between the three- and two-dimensional lifetimes, which can enhance the ability of receptors to discriminate between similar ligands.
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Affiliation(s)
- Jun F. Allard
- Department of Mathematics, University of California, Davis, California
| | - Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
- Centre for Mathematical Biology, University of Oxford, Oxford, United Kingdom
| | - Daniel Coombs
- Department of Mathematics and Institute of Applied Mathematics, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
Signaling processes between various immune cells involve large-scale spatial reorganization of receptors and signaling molecules within the cell-cell junction. These structures, now collectively referred to as immune synapses, interleave physical and mechanical processes with the cascades of chemical reactions that constitute signal transduction systems. Molecular level clustering, spatial exclusion, and long-range directed transport are all emerging as key regulatory mechanisms. The study of these processes is drawing researchers from physical sciences to join the effort and represents a rapidly growing branch of biophysical chemistry. Recent advances in physical and quantitative analyses of signaling within the immune synapses are reviewed here.
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Affiliation(s)
- Michael L Dustin
- Program in Molecular Pathogenesis, Skirball Institute of Biomolecular Medicine and Department of Pathology, New York University School of Medicine, New York, New York 10016, USA.
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Schubert DA, Gordo S, Sabatino JJ, Vardhana S, Gagnon E, Sethi DK, Seth NP, Choudhuri K, Reijonen H, Nepom GT, Evavold BD, Dustin ML, Wucherpfennig KW. Self-reactive human CD4 T cell clones form unusual immunological synapses. ACTA ACUST UNITED AC 2012; 209:335-52. [PMID: 22312112 PMCID: PMC3280872 DOI: 10.1084/jem.20111485] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Compared with influenza-specific T cells, self-reactive T cells from patients with multiple sclerosis or type 1 diabetes fail to slow down and do not form normal immunological synapses upon encounter with cognate self-peptide presented by MHC. Recognition of self–peptide-MHC (pMHC) complexes by CD4 T cells plays an important role in the pathogenesis of many autoimmune diseases. We analyzed formation of immunological synapses (IS) in self-reactive T cell clones from patients with multiple sclerosis and type 1 diabetes. All self-reactive T cells contained a large number of phosphorylated T cell receptor (TCR) microclusters, indicative of active TCR signaling. However, they showed little or no visible pMHC accumulation or transport of TCR–pMHC complexes into a central supramolecular activation cluster (cSMAC). In contrast, influenza-specific T cells accumulated large quantities of pMHC complexes in microclusters and a cSMAC, even when presented with 100-fold lower pMHC densities. The self-reactive T cells also maintained a high degree of motility, again in sharp contrast to virus-specific T cells. 2D affinity measurements of three of these self-reactive T cell clones demonstrated a normal off-rate but a slow on-rate of TCR binding to pMHC. These unusual IS features may facilitate escape from negative selection by self-reactive T cells encountering very small amounts of self-antigen in the thymus. However, these same features may enable acquisition of effector functions by self-reactive T cells encountering large amounts of self-antigen in the target organ of the autoimmune disease.
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Affiliation(s)
- David A Schubert
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
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