1
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Gaud G, Achar S, Bourassa FXP, Davies J, Hatzihristidis T, Choi S, Kondo T, Gossa S, Lee J, Juneau P, Taylor N, Hinrichs CS, McGavern DB, François P, Altan-Bonnet G, Love PE. CD3ζ ITAMs enable ligand discrimination and antagonism by inhibiting TCR signaling in response to low-affinity peptides. Nat Immunol 2023; 24:2121-2134. [PMID: 37945821 DOI: 10.1038/s41590-023-01663-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 09/29/2023] [Indexed: 11/12/2023]
Abstract
The T cell antigen receptor (TCR) contains ten immunoreceptor tyrosine-based activation motif (ITAM) signaling sequences distributed within six CD3 subunits; however, the reason for such structural complexity and multiplicity is unclear. Here we evaluated the effect of inactivating the three CD3ζ chain ITAMs on TCR signaling and T cell effector responses using a conditional 'switch' mouse model. Unexpectedly, we found that T cells expressing TCRs containing inactivated (non-signaling) CD3ζ ITAMs (6F-CD3ζ) exhibited reduced ability to discriminate between low- and high-affinity ligands, resulting in enhanced signaling and cytokine responses to low-affinity ligands because of a previously undetected inhibitory function of CD3ζ ITAMs. Also, 6F-CD3ζ TCRs were refractory to antagonism, as predicted by a new in silico adaptive kinetic proofreading model that revises the role of ITAM multiplicity in TCR signaling. Finally, T cells expressing 6F-CD3ζ displayed enhanced cytolytic activity against solid tumors expressing low-affinity ligands, identifying a new counterintuitive approach to TCR-mediated cancer immunotherapy.
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Affiliation(s)
- Guillaume Gaud
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Sooraj Achar
- Immunodynamics Section, Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - François X P Bourassa
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, Quebec, Canada
- Department of Physics, McGill University, Montréal QC, Canada
| | - John Davies
- Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
- Department of Safety Assessment, Genentech, Inc., San Francisco, CA, USA
| | - Teri Hatzihristidis
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Seeyoung Choi
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Taisuke Kondo
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Selamawit Gossa
- Viral Immunology & Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Jan Lee
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Paul Juneau
- National Institutes of Health Library, Office of Research Services, National Institutes of Health, Bethesda, MD, USA
| | - Naomi Taylor
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Christian S Hinrichs
- Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Dorian B McGavern
- Viral Immunology & Intravital Imaging Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Paul François
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, Quebec, Canada
- Mila Québec, Montréal, Quebec, Canada
| | - Grégoire Altan-Bonnet
- Immunodynamics Section, Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Paul E Love
- Hematopoiesis and Lymphocyte Biology Section, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, Bethesda, MD, USA.
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2
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Li J, Xiao Z, Wang D, Jia L, Nie S, Zeng X, Hu W. The screening, identification, design and clinical application of tumor-specific neoantigens for TCR-T cells. Mol Cancer 2023; 22:141. [PMID: 37649123 PMCID: PMC10466891 DOI: 10.1186/s12943-023-01844-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 08/16/2023] [Indexed: 09/01/2023] Open
Abstract
Recent advances in neoantigen research have accelerated the development of tumor immunotherapies, including adoptive cell therapies (ACTs), cancer vaccines and antibody-based therapies, particularly for solid tumors. With the development of next-generation sequencing and bioinformatics technology, the rapid identification and prediction of tumor-specific antigens (TSAs) has become possible. Compared with tumor-associated antigens (TAAs), highly immunogenic TSAs provide new targets for personalized tumor immunotherapy and can be used as prospective indicators for predicting tumor patient survival, prognosis, and immune checkpoint blockade response. Here, the identification and characterization of neoantigens and the clinical application of neoantigen-based TCR-T immunotherapy strategies are summarized, and the current status, inherent challenges, and clinical translational potential of these strategies are discussed.
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Affiliation(s)
- Jiangping Li
- Division of Thoracic Tumor Multimodality Treatment, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, People's Republic of China.
| | - Zhiwen Xiao
- Department of Otolaryngology Head and Neck Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510655, People's Republic of China
| | - Donghui Wang
- Department of Radiation Oncology, The Third Affiliated Hospital Sun Yat-Sen University, Guangzhou, 510630, People's Republic of China
| | - Lei Jia
- International Health Medicine Innovation Center, Shenzhen University, Shenzhen, 518060, People's Republic of China
| | - Shihong Nie
- Department of Radiation Oncology, West China Hospital, Sichuan University, Cancer Center, Chengdu, 610041, People's Republic of China
| | - Xingda Zeng
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Wei Hu
- Division of Vascular Surgery, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, People's Republic of China
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3
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Jiang H, Wang S. Immune cells use active tugging forces to distinguish affinity and accelerate evolution. Proc Natl Acad Sci U S A 2023; 120:e2213067120. [PMID: 36897986 PMCID: PMC10089171 DOI: 10.1073/pnas.2213067120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 01/11/2023] [Indexed: 03/12/2023] Open
Abstract
Cells are known to exert forces to sense their physical surroundings for guidance of motion and fate decisions. Here, we propose that cells might do mechanical work to drive their own evolution, taking inspiration from the adaptive immune system. Growing evidence indicates that immune B cells-capable of rapid Darwinian evolution-use cytoskeletal forces to actively extract antigens from other cells' surfaces. To elucidate the evolutionary significance of force usage, we develop a theory of tug-of-war antigen extraction that maps receptor binding characteristics to clonal reproductive fitness, revealing physical determinants of selection strength. This framework unifies mechanosensing and affinity-discrimination capabilities of evolving cells: Pulling against stiff antigen tethers enhances discrimination stringency at the expense of absolute extraction. As a consequence, active force usage can accelerate adaptation but may also cause extinction of cell populations, resulting in an optimal range of pulling strength that matches molecular rupture forces observed in cells. Our work suggests that nonequilibrium, physical extraction of environmental signals can make biological systems more evolvable at a moderate energy cost.
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Affiliation(s)
- Hongda Jiang
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA90095
| | - Shenshen Wang
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA90095
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4
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Huseby ES, Teixeiro E. The perception and response of T cells to a changing environment are based on the law of initial value. Sci Signal 2022; 15:eabj9842. [PMID: 35639856 PMCID: PMC9290192 DOI: 10.1126/scisignal.abj9842] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
αβ T cells are critical components of the adaptive immune system and are capable of inducing sterilizing immunity after pathogen infection and eliminating transformed tumor cells. The development and function of T cells are controlled through the T cell antigen receptor, which recognizes peptides displayed on major histocompatibility complex (MHC) molecules. Here, we review how T cells generate the ability to recognize self-peptide-bound MHC molecules and use signals derived from these interactions to instruct cellular development, activation thresholds, and functional specialization in the steady state and during immune responses. We argue that the basic tenants of T cell development and function follow Weber-Fetcher's law of just noticeable differences and Wilder's law of initial value. Together, these laws argue that the ability of a system to respond and the quality of that response are scalable to the basal state of that system. Manifestation of these laws in T cells generates clone-specific activation thresholds that are based on perceivable differences between homeostasis and pathogen encounter (self versus nonself discrimination), as well as poised states for subsequent differentiation into specific effector cell lineages.
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Affiliation(s)
- Eric S. Huseby
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Emma Teixeiro
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
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5
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Dam T, Chouliara M, Junghans V, Jönsson P. Supported Lipid Bilayers and the Study of Two-Dimensional Binding Kinetics. Front Mol Biosci 2022; 9:833123. [PMID: 35252352 PMCID: PMC8896763 DOI: 10.3389/fmolb.2022.833123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Binding between protein molecules on contacting cells is essential in initiating and regulating several key biological processes. In contrast to interactions between molecules in solution, these events are restricted to the two-dimensional (2D) plane of the meeting cell surfaces. However, converting between the more commonly available binding kinetics measured in solution and the so-called 2D binding kinetics has proven a complicated task since for the latter several factors other than the protein-protein interaction per se have an impact. A few important examples of these are: protein density, membrane fluctuations, force on the bond and the use of auxiliary binding molecules. The development of model membranes, and in particular supported lipid bilayers (SLBs), has made it possible to simplify the studied contact to analyze these effects and to measure 2D binding kinetics of individual protein-protein interactions. We will in this review give an overview of, and discuss, how different SLB systems have been used for this and compare different methods to measure binding kinetics in cell-SLB contacts. Typically, the SLB is functionalized with fluorescently labelled ligands whose interaction with the corresponding receptor on a binding cell can be detected. This interaction can either be studied 1) by an accumulation of ligands in the cell-SLB contact, whose magnitude depends on the density of the proteins and binding affinity of the interaction, or 2) by tracking single ligands in the SLB, which upon interaction with a receptor result in a change of motion of the diffusing ligand. The advantages and disadvantages of other methods measuring 2D binding kinetics will also be discussed and compared to the fluorescence-based methods. Although binding kinetic measurements in cell-SLB contacts have provided novel information on how ligands interact with receptors in vivo the number of these measurements is still limited. This is influenced by the complexity of the system as well as the required experimental time. Moreover, the outcome can vary significantly between studies, highlighting the necessity for continued development of methods to study 2D binding kinetics with higher precision and ease.
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Affiliation(s)
- Tommy Dam
- Department of Chemistry, Lund University, Lund, Sweden
| | | | - Victoria Junghans
- Nuffield Department of Medicine, CAMS Oxford Institute, University of Oxford, Oxford, United Kingdom
| | - Peter Jönsson
- Department of Chemistry, Lund University, Lund, Sweden
- *Correspondence: Peter Jönsson,
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6
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Mechanoregulation of PDZ Proteins, An Emerging Function. Methods Mol Biol 2021; 2256:257-275. [PMID: 34014527 DOI: 10.1007/978-1-0716-1166-1_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mechanical forces have emerged as essential regulators of cell organization, proliferation, migration, and polarity to regulate cellular and tissue homeostasis. Changes in forces or loss of the cellular response to them can result in abnormal embryonic development and diseases. Over the past two decades, many efforts have been put in deciphering the molecular mechanisms that convert forces into biochemical signals, allowing for the identification of many mechanotransducer proteins. Here we discuss how PDZ proteins are emerging as new mechanotransducer proteins by altering their conformations or localizations upon force loads, leading to the formation of macromolecular modules tethering the cell membrane to the actin cytoskeleton.
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7
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Ghosh S, Di Bartolo V, Tubul L, Shimoni E, Kartvelishvily E, Dadosh T, Feigelson SW, Alon R, Alcover A, Haran G. ERM-Dependent Assembly of T Cell Receptor Signaling and Co-stimulatory Molecules on Microvilli prior to Activation. Cell Rep 2021; 30:3434-3447.e6. [PMID: 32160548 DOI: 10.1016/j.celrep.2020.02.069] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/16/2019] [Accepted: 02/18/2020] [Indexed: 01/25/2023] Open
Abstract
T cell surfaces are covered with microvilli, actin-rich and flexible protrusions. We use super-resolution microscopy to show that ≥90% of T cell receptor (TCR) complex molecules TCRαβ and TCRζ, as well as the co-receptor CD4 (cluster of differentiation 4) and the co-stimulatory molecule CD2, reside on microvilli of resting human T cells. Furthermore, TCR proximal signaling molecules involved in the initial stages of the immune response, including the protein tyrosine kinase Lck (lymphocyte-specific protein tyrosine kinase) and the key adaptor LAT (linker for activation of T cells), are also enriched on microvilli. Notably, phosphorylated proteins of the ERM (ezrin, radixin, and moesin) family colocalize with TCRαβ as well as with actin filaments, implying a role for one or more ERMs in linking the TCR complex to the actin cytoskeleton within microvilli. Our results establish microvilli as key signaling hubs, in which the TCR complex and its proximal signaling molecules and adaptors are preassembled prior to activation in an ERM-dependent manner, facilitating initial antigen sensing.
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Affiliation(s)
- Shirsendu Ghosh
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Vincenzo Di Bartolo
- Lymphocyte Cell Biology Unit, INSERM U1221, Department of Immunology, Institut Pasteur, Paris 75015, France
| | - Liron Tubul
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eyal Shimoni
- Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Elena Kartvelishvily
- Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tali Dadosh
- Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sara W Feigelson
- Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ronen Alon
- Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Andres Alcover
- Lymphocyte Cell Biology Unit, INSERM U1221, Department of Immunology, Institut Pasteur, Paris 75015, France
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
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8
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Mordechay L, Le Saux G, Edri A, Hadad U, Porgador A, Schvartzman M. Mechanical Regulation of the Cytotoxic Activity of Natural Killer Cells. ACS Biomater Sci Eng 2020; 7:122-132. [DOI: 10.1021/acsbiomaterials.0c01121] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Lital Mordechay
- Department of Materials Engineering, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
- Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Guillaume Le Saux
- Department of Materials Engineering, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
- Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Avishay Edri
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Uzi Hadad
- Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Angel Porgador
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Mark Schvartzman
- Department of Materials Engineering, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
- Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
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9
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Kolawole EM, Lamb TJ, Evavold BD. Relationship of 2D Affinity to T Cell Functional Outcomes. Int J Mol Sci 2020; 21:ijms21217969. [PMID: 33120989 PMCID: PMC7662510 DOI: 10.3390/ijms21217969] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/14/2020] [Accepted: 10/23/2020] [Indexed: 12/11/2022] Open
Abstract
T cells are critical for a functioning adaptive immune response and a strong correlation exists between T cell responses and T cell receptor (TCR): peptide-loaded MHC (pMHC) binding. Studies that utilize pMHC tetramer, multimers, and assays of three-dimensional (3D) affinity have provided advancements in our understanding of T cell responses across different diseases. However, these technologies focus on higher affinity and avidity T cells while missing the lower affinity responders. Lower affinity TCRs in expanded polyclonal populations almost always constitute a significant proportion of the response with cells mediating different effector functions associated with variation in the proportion of high and low affinity T cells. Since lower affinity T cells expand and are functional, a fully inclusive view of T cell responses is required to accurately interpret the role of affinity for adaptive T cell immunity. For example, low affinity T cells are capable of inducing autoimmune disease and T cells with an intermediate affinity have been shown to exhibit an optimal anti-tumor response. Here, we focus on how affinity of the TCR may relate to T cell phenotype and provide examples where 2D affinity influences functional outcomes.
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10
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Stein JV, Ruef N. Regulation of global CD8 + T-cell positioning by the actomyosin cytoskeleton. Immunol Rev 2020; 289:232-249. [PMID: 30977193 DOI: 10.1111/imr.12759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 12/12/2022]
Abstract
CD8+ T cells have evolved as one of the most motile mammalian cell types, designed to continuously scan peptide-major histocompatibility complexes class I on the surfaces of other cells. Chemoattractants and adhesion molecules direct CD8+ T-cell homing to and migration within secondary lymphoid organs, where these cells colocalize with antigen-presenting dendritic cells in confined tissue volumes. CD8+ T-cell activation induces a switch to infiltration of non-lymphoid tissue (NLT), which differ in their topology and biophysical properties from lymphoid tissue. Here, we provide a short overview on regulation of organism-wide trafficking patterns during naive T-cell recirculation and their switch to non-lymphoid tissue homing during activation. The migratory lifestyle of CD8+ T cells is regulated by their actomyosin cytoskeleton, which translates chemical signals from surface receptors into mechanical work. We explore how properties of the actomyosin cytoskeleton and its regulators affect CD8+ T cell function in lymphoid and non-lymphoid tissue, combining recent findings in the field of cell migration and actin network regulation with tissue anatomy. Finally, we hypothesize that under certain conditions, intrinsic regulation of actomyosin dynamics may render NLT CD8+ T-cell populations less dependent on input from extrinsic signals during tissue scanning.
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Affiliation(s)
- Jens V Stein
- Department of Oncology, Microbiology and Immunology, University of Fribourg, Fribourg, Switzerland
| | - Nora Ruef
- Department of Oncology, Microbiology and Immunology, University of Fribourg, Fribourg, Switzerland
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11
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Shen Z, Liu S, Li X, Wan Z, Mao Y, Chen C, Liu W. Conformational change within the extracellular domain of B cell receptor in B cell activation upon antigen binding. eLife 2019; 8:42271. [PMID: 31290744 PMCID: PMC6620044 DOI: 10.7554/elife.42271] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 06/27/2019] [Indexed: 12/20/2022] Open
Abstract
B lymphocytes use B cell receptors (BCRs) to recognize antigens. It is still not clear how BCR transduces antigen-specific physical signals upon binding across cell membrane for the conversion to chemical signals, triggering downstream signaling cascades. It is hypothesized that through a series of conformational changes within BCR, antigen engagement in the extracellular domain of BCR is transduced to its intracellular domain. By combining site-specific labeling methodology and FRET-based assay, we monitored conformational changes in the extracellular domains within BCR upon antigen engagement. Conformational changes within heavy chain of membrane-bound immunoglobulin (mIg), as well as conformational changes in the spatial relationship between mIg and Igβ were observed. These conformational changes were correlated with the strength of BCR activation and were distinct in IgM- and IgG-BCR. These findings provide molecular mechanisms to explain the fundamental aspects of BCR activation and a framework to investigate ligand-induced molecular events in immune receptors.
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Affiliation(s)
- Zhixun Shen
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Sichen Liu
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Xinxin Li
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Zhengpeng Wan
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Youxiang Mao
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
| | - Chunlai Chen
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
| | - Wanli Liu
- Laboratory of Lymphocyte Signaling & Molecular Imaging, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, Center for Life Sciences, Beijing Key Lab for Immunological Research on Chronic Diseases, Tsinghua University, Beijing, China
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12
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Pullen RH, Abel SM. Mechanical feedback enables catch bonds to selectively stabilize scanning microvilli at T-cell surfaces. Mol Biol Cell 2019; 30:2087-2095. [PMID: 31116687 PMCID: PMC6727777 DOI: 10.1091/mbc.e19-01-0048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
T-cells use microvilli to search the surfaces of antigen-presenting cells for antigenic ligands. The active motion of scanning microvilli provides a force-generating mechanism that is intriguing in light of single-molecule experiments showing that applied forces increase the lifetimes of stimulatory receptor–ligand bonds (catch-bond behavior). In this work, we introduce a theoretical framework to explore the motion of a microvillar tip above an antigen-presenting surface when receptors on the tip stochastically bind to ligands on the surface and dissociate from them in a force-dependent manner. Forces on receptor-ligand bonds impact the motion of the microvillus, leading to feedback between binding and microvillar motion. We use computer simulations to show that the average microvillar velocity varies in a ligand-dependent manner; that catch bonds generate responses in which some microvilli almost completely stop, while others move with a broad distribution of velocities; and that the frequency of stopping depends on the concentration of stimulatory ligands. Typically, a small number of catch bonds initially immobilize the microvillus, after which additional bonds accumulate and increase the cumulative receptor-engagement time. Our results demonstrate that catch bonds can selectively slow and stabilize scanning microvilli, suggesting a physical mechanism that may contribute to antigen discrimination by T-cells.
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Affiliation(s)
- Robert H Pullen
- Department of Chemical and Biomolecular Engineering, National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN 37996
| | - Steven M Abel
- Department of Chemical and Biomolecular Engineering, National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN 37996
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13
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Hammer JA, Wang JC, Saeed M, Pedrosa AT. Origin, Organization, Dynamics, and Function of Actin and Actomyosin Networks at the T Cell Immunological Synapse. Annu Rev Immunol 2019; 37:201-224. [PMID: 30576253 PMCID: PMC8343269 DOI: 10.1146/annurev-immunol-042718-041341] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The engagement of a T cell with an antigen-presenting cell (APC) or activating surface results in the formation within the T cell of several distinct actin and actomyosin networks. These networks reside largely within a narrow zone immediately under the T cell's plasma membrane at its site of contact with the APC or activating surface, i.e., at the immunological synapse. Here we review the origin, organization, dynamics, and function of these synapse-associated actin and actomyosin networks. Importantly, recent insights into the nature of these actin-based cytoskeletal structures were made possible in several cases by advances in light microscopy.
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Affiliation(s)
- John A Hammer
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Jia C Wang
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Mezida Saeed
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Antonio T Pedrosa
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
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14
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Rossy J, Laufer JM, Legler DF. Role of Mechanotransduction and Tension in T Cell Function. Front Immunol 2018; 9:2638. [PMID: 30519239 PMCID: PMC6251326 DOI: 10.3389/fimmu.2018.02638] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/26/2018] [Indexed: 12/23/2022] Open
Abstract
T cell migration from blood to, and within lymphoid organs and tissue, as well as, T cell activation rely on complex biochemical signaling events. But T cell migration and activation also take place in distinct mechanical environments and lead to drastic morphological changes and reorganization of the acto-myosin cytoskeleton. In this review we discuss how adhesion proteins and the T cell receptor act as mechanosensors to translate these mechanical contexts into signaling events. We further discuss how cell tension could bring a significant contribution to the regulation of T cell signaling and function.
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Affiliation(s)
- Jérémie Rossy
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Julia M Laufer
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Daniel F Legler
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland.,Department of Biology, University of Konstanz, Konstanz, Germany
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15
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Junghans V, Santos AM, Lui Y, Davis SJ, Jönsson P. Dimensions and Interactions of Large T-Cell Surface Proteins. Front Immunol 2018; 9:2215. [PMID: 30319654 PMCID: PMC6170634 DOI: 10.3389/fimmu.2018.02215] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 09/06/2018] [Indexed: 11/23/2022] Open
Abstract
The first step of the adaptive immune response involves the interaction of T cells that express T-cell receptors (TCRs) with peptide-loaded major histocompatibility complexes expressed by antigen-presenting cells (APCs). Exactly how this leads to activation of the TCR and to downstream signaling is uncertain, however. Recent findings suggest that one of the key events is the exclusion of the large receptor-type tyrosine phosphatase CD45, from close contacts formed at sites of T-cell/APC interaction. If this is true, a full understanding of how close contact formation leads to signaling would require insights into the structures of, and interactions between, large membrane proteins like CD45 and other proteins forming the glycocalyx, such as CD43. Structural insights into the overall dimensions of these proteins using crystallographic methods are hard to obtain, and their conformations on the cell surface are also unknown. Several imaging-based optical microscopy techniques have however been developed for analyzing protein dimensions and orientation on model cell surfaces with nanometer precision. Here we review some of these methods with a focus on the use of hydrodynamic trapping, which relies on liquid flow from a micropipette to move and trap membrane-associated fluorescently labeled molecules. Important insights that have been obtained include (i) how protein flexibility and coverage might affect the effective heights of these molecules, (ii) the height of proteins on the membrane as a key parameter determining how they will distribute in cell-cell contacts, and (iii) how repulsive interactions between the extracellular parts of the proteins influences protein aggregation and distribution.
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Affiliation(s)
| | - Ana Mafalda Santos
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Yuan Lui
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Simon J. Davis
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Peter Jönsson
- Department of Chemistry, Lund University, Lund, Sweden
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16
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Feng Y, Reinherz EL, Lang MJ. αβ T Cell Receptor Mechanosensing Forces out Serial Engagement. Trends Immunol 2018; 39:596-609. [PMID: 30060805 PMCID: PMC6154790 DOI: 10.1016/j.it.2018.05.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 05/15/2018] [Accepted: 05/31/2018] [Indexed: 11/08/2022]
Abstract
T lymphocytes use αβ T cell receptors (TCRs) to recognize
sparse antigenic peptides bound to MHC molecules (pMHCs) arrayed on
antigen-presenting cells (APCs). Contrary to conventional receptor–ligand
associations exemplified by antigen-antibody interactions, forces play a crucial
role in nonequilibrium mechanosensor-based T cell activation. Both T cell
motility and local cytoskeleton machinery exert forces (i.e., generate loads) on
TCR–pMHC bonds. We review biological features of the load-dependent
activation process as revealed by optical tweezers single molecule/single cell
and other biophysical measurements. The findings link pMHC-triggered TCRs to
single cytoskeletal motors; define the importance of energized anisotropic
(i.e., force direction dependent) activation; and characterize immunological
synapse formation as digital, revealing no serial requirement. The emerging
picture suggests new approaches for the monitoring and design of cytotoxic T
lymphocyte (CTL)-based immunotherapy.
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Affiliation(s)
- Yinnian Feng
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Ellis L Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37235, USA.
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17
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Sawicka A, Babataheri A, Dogniaux S, Barakat AI, Gonzalez-Rodriguez D, Hivroz C, Husson J. Micropipette force probe to quantify single-cell force generation: application to T-cell activation. Mol Biol Cell 2017; 28:3229-3239. [PMID: 28931600 PMCID: PMC5687025 DOI: 10.1091/mbc.e17-06-0385] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/08/2017] [Accepted: 09/12/2017] [Indexed: 11/11/2022] Open
Abstract
We describe the micropipette force probe, a novel technique that uses a micropipette as a flexible cantilever that aspirates a coated microbead and brings it into contact with a cell. We apply the technique to quantify mechanical and morphological events occurring during T-cell activation. In response to engagement of surface molecules, cells generate active forces that regulate many cellular processes. Developing tools that permit gathering mechanical and morphological information on these forces is of the utmost importance. Here we describe a new technique, the micropipette force probe, that uses a micropipette as a flexible cantilever that can aspirate at its tip a bead that is coated with molecules of interest and is brought in contact with the cell. This technique simultaneously allows tracking the resulting changes in cell morphology and mechanics as well as measuring the forces generated by the cell. To illustrate the power of this technique, we applied it to the study of human primary T lymphocytes (T-cells). It allowed the fine monitoring of pushing and pulling forces generated by T-cells in response to various activating antibodies and bending stiffness of the micropipette. We further dissected the sequence of mechanical and morphological events occurring during T-cell activation to model force generation and to reveal heterogeneity in the cell population studied. We also report the first measurement of the changes in Young’s modulus of T-cells during their activation, showing that T-cells stiffen within the first minutes of the activation process.
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Affiliation(s)
- Anna Sawicka
- Laboratoire d'Hydrodynamique (LadHyX), Department of Mechanics, Ecole polytechnique-CNRS UMR7646, 91128 Palaiseau, France.,Institut Curie Section Recherche, INSERM U932 and PSL Research University, 75005 Paris, France
| | - Avin Babataheri
- Laboratoire d'Hydrodynamique (LadHyX), Department of Mechanics, Ecole polytechnique-CNRS UMR7646, 91128 Palaiseau, France
| | - Stéphanie Dogniaux
- Institut Curie Section Recherche, INSERM U932 and PSL Research University, 75005 Paris, France
| | - Abdul I Barakat
- Laboratoire d'Hydrodynamique (LadHyX), Department of Mechanics, Ecole polytechnique-CNRS UMR7646, 91128 Palaiseau, France
| | | | - Claire Hivroz
- Institut Curie Section Recherche, INSERM U932 and PSL Research University, 75005 Paris, France
| | - Julien Husson
- Laboratoire d'Hydrodynamique (LadHyX), Department of Mechanics, Ecole polytechnique-CNRS UMR7646, 91128 Palaiseau, France
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18
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Catch Bonds at T Cell Interfaces: Impact of Surface Reorganization and Membrane Fluctuations. Biophys J 2017; 113:120-131. [PMID: 28700910 DOI: 10.1016/j.bpj.2017.05.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/07/2017] [Accepted: 05/19/2017] [Indexed: 01/30/2023] Open
Abstract
Catch bonds are characterized by average lifetimes that initially increase with increasing tensile force. Recently, they have been implicated in T cell activation, where small numbers of antigenic receptor-ligand bonds at a cell-cell interface can stimulate a T cell. Here, we use computational methods to investigate small numbers of bonds at the interface between two membranes. We characterize the time-dependent forces on the bonds in response to changes in the membrane shape and the organization of other surface molecules. We then determine the distributions of bond lifetimes using recent force-dependent lifetime data for T cell receptors bound to various ligands. Strong agonists, which exhibit catch bond behavior, are markedly more likely to remain intact than an antagonist whose average lifetime decreases with increasing force. Thermal fluctuations of the membrane shape enhance the decay of the average force on a bond, but also lead to fluctuations of the force. These fluctuations promote bond rupture, but the effect is buffered by catch bonds. When more than one bond is present, the bonds experience reduced average forces that depend on their relative positions, leading to changes in bond lifetimes. Our results highlight the importance of force-dependent binding kinetics when bonds experience time-dependent and fluctuating forces, as well as potential consequences of collective bond behavior relevant to T cell activation.
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19
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Contractile actomyosin arcs promote the activation of primary mouse T cells in a ligand-dependent manner. PLoS One 2017; 12:e0183174. [PMID: 28817635 PMCID: PMC5560663 DOI: 10.1371/journal.pone.0183174] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/31/2017] [Indexed: 12/16/2022] Open
Abstract
Mechano-transduction is an emerging but still poorly understood component of T cell activation. Here we investigated the ligand-dependent contribution made by contractile actomyosin arcs populating the peripheral supramolecular activation cluster (pSMAC) region of the immunological synapse (IS) to T cell receptor (TCR) microcluster transport and proximal signaling in primary mouse T cells. Using super resolution microscopy, OT1-CD8+ mouse T cells, and two ovalbumin (OVA) peptides with different affinities for the TCR, we show that the generation of organized actomyosin arcs depends on ligand potency and the ability of myosin 2 to contract actin filaments. While weak ligands induce disorganized actomyosin arcs, strong ligands result in organized actomyosin arcs that correlate well with tension-sensitive CasL phosphorylation and the accumulation of ligands at the IS center. Blocking myosin 2 contractility greatly reduces the difference in the extent of Src and LAT phosphorylation observed between the strong and the weak ligand, arguing that myosin 2-dependent force generation within actin arcs contributes to ligand discrimination. Together, our data are consistent with the idea that actomyosin arcs in the pSMAC region of the IS promote a mechano-chemical feedback mechanism that amplifies the accumulation of critical signaling molecules at the IS.
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20
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Faro J, Castro M, Molina-París C. A unifying mathematical framework for experimental TCR-pMHC kinetic constants. Sci Rep 2017; 7:46741. [PMID: 28443634 PMCID: PMC5405415 DOI: 10.1038/srep46741] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 03/27/2017] [Indexed: 12/02/2022] Open
Abstract
Receptor binding and triggering are central in Immunology as T cells activated through their T cell receptors (TCR) by protein antigens orchestrate immune responses. In order to understand receptor-ligand interactions, many groups working with different experimental techniques and assays have generated a vast body of knowledge during the last decades. However, in recent years a type of assays, referred to as two-dimensional or membrane-to-membrane, has questioned our current understanding of the role of different kinetic constants (for instance, on- versus off-rate constants) on TCR-ligand interaction and subsequent T cell activation. Here we present a general mathematical framework that provides a unifying umbrella to relate fundamental and effective (or experimentally determined) kinetic constants, as well as describe and compare state-of-the-art experimental methods. Our framework is able to predict the correlations between functional output, such as 1/EC50, and effective kinetic constants for a range of different experimental assays (in two and three dimensions). Furthermore, our approach can be applied beyond Immunology, and serve as a “translation method” for the biochemical characterization of receptor-ligand interactions.
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Affiliation(s)
- Jose Faro
- Area of Immunology, Faculty of Biology, and Biomedical Research Center (CINBIO), Universidade de Vigo, Vigo, Spain.,Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Mario Castro
- Grupo Interdisciplinar de Sistemas Complejos (GISC) and DNL, Universidad Pontificia Comillas, Madrid E-28015, Spain.,Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK
| | - Carmen Molina-París
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK
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21
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Murugesan S, Hong J, Yi J, Li D, Beach JR, Shao L, Meinhardt J, Madison G, Wu X, Betzig E, Hammer JA. Formin-generated actomyosin arcs propel T cell receptor microcluster movement at the immune synapse. J Cell Biol 2016; 215:383-399. [PMID: 27799367 PMCID: PMC5100289 DOI: 10.1083/jcb.201603080] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 09/28/2016] [Indexed: 11/22/2022] Open
Abstract
Murugesan et al. report that actomyosin arcs at the T cell synapse are formin-generated structures that directly propel T cell receptor cluster movement. The authors reveal the origin, organization, and functions of a major cytoskeletal network during synapse maturation. Actin assembly and inward flow in the plane of the immunological synapse (IS) drives the centralization of T cell receptor microclusters (TCR MCs) and the integrin leukocyte functional antigen 1 (LFA-1). Using structured-illumination microscopy (SIM), we show that actin arcs populating the medial, lamella-like region of the IS arise from linear actin filaments generated by one or more formins present at the IS distal edge. After traversing the outer, Arp2/3-generated, lamellipodia-like region of the IS, these linear filaments are organized by myosin II into antiparallel concentric arcs. Three-dimensional SIM shows that active LFA-1 often aligns with arcs, whereas TCR MCs commonly reside between arcs, and total internal reflection fluorescence SIM shows TCR MCs being swept inward by arcs. Consistently, disrupting actin arc formation via formin inhibition results in less centralized TCR MCs, missegregated integrin clusters, decreased T–B cell adhesion, and diminished TCR signaling. Together, our results define the origin, organization, and functional significance of a major actomyosin contractile structure at the IS that directly propels TCR MC transport.
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Affiliation(s)
- Sricharan Murugesan
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jinsung Hong
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jason Yi
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Dong Li
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147.,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Jordan R Beach
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Lin Shao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147
| | - John Meinhardt
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Grey Madison
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Xufeng Wu
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Eric Betzig
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147
| | - John A Hammer
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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22
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Abstract
Stroke induces a local inflammatory reaction and a plethora of innate immune responses in the brain where antigen-presenting cells become prominent. However, to date, it is still unclear whether antigen presentation is relevant to the neuropathological and functional outcome of stroke. Stroke does not trigger overt autoimmune reactions, but neural antigens have been found in lymphoid tissues of patient with stroke and it is unknown whether they promote tolerance or immune reactions that under certain conditions might contribute to the functional worsening observed in some patients. Autoantibodies to neural molecules have also been reported in patients with stroke, but the subclass of antibodies is important for their function, and the contribution of such findings to stroke outcome is not yet clear. Notably, stroke induces immunodepression highlighted by a transient lymphopenia, lymphoid organ atrophy, and monocyte deactivation. While these effects might reduce the chances of autoreactivity, they increase the risk of infection in patients with stroke and most frequently in those with severe stroke. Therefore any potential brain protective effect of stroke-induced immunodepression by attenuating or preventing lymphocyte-mediated brain damage is confounded by stroke severity and an increased incidence of infections. Systemic inflammation due to a number of comorbidities that are frequent in patients with stroke is also associated to a poor outcome. Herein, we review some relevant findings regarding the identification of neural antigens in stroke and discuss their potential contribution to the functional outcome of stroke.
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Affiliation(s)
- Francesc Miró-Mur
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
| | - Xabier Urra
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
- Functional Unit of Cerebrovascular Diseases, Hospital Clínic, Barcelona, Spain
| | - Mattia Gallizioli
- Department of Brain Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain
| | - Angel Chamorro
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
- Functional Unit of Cerebrovascular Diseases, Hospital Clínic, Barcelona, Spain
| | - Anna M Planas
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain.
- Department of Brain Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain.
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23
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Wang L, Kang FB, Sun N, Wang J, Chen W, Li D, Shan BE. The tumor suppressor miR-124 inhibits cell proliferation and invasion by targeting B7-H3 in osteosarcoma. Tumour Biol 2016; 37:14939-14947. [PMID: 27644254 DOI: 10.1007/s13277-016-5386-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/09/2016] [Indexed: 12/11/2022] Open
Abstract
Our previous studies have shown that the expression level of B7 homolog 3 (B7-H3) was correlated with clinical staging and prognosis of osteosarcoma (OS) patients, and its silencing inhibited the proliferation and invasion of OS cells in vitro. However, its overexpression mechanism behind was far from elucidated. On the basis of bioinformatics and the preliminary screening data, we hypothesized that miR-124 might play an important role in OS development and as a lead candidate for modulating B7-H3 expression. In this study, we found that miR-124 was downregulated significantly in OS tumor tissue, compared to normal adjacent tissues (NATs). Lower miR-124 expression levels were associated with advanced Ennecking stage, lower tumor differentiation, and common pulmonary metastasis. The 5-year overall survival rate in the miR-124 upregulated group was 61.5 %, while with low miR-124 expression, only 11.8 % survived. Further studies in vitro showed that B7-H3 was a direct target of miR-124. Overexpression of miR-124 decreased B7-H3 mRNA and protein level and inhibited B7-H3 3'-UTR reporter activity. Treatment of OS cells with miR-124 mimics induced the inhibition of cell growth and invasion in vitro, which could be abrogated by transfected by B7-H3 expression vector. Our findings highlight the potential application of miR-124 as a novel onco-miRNA in OS, and its oncogenic effects are mediated chiefly through downregulation of B7-H3, thus suggesting a model for identifying miR-124 that can be exploited to improve the therapeutic potential efficacy of mAb targeting to B7-H3.
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Affiliation(s)
- Ling Wang
- Cancer Research Institute, the Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China.,Department of Orthopedics, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China
| | - Fu-Biao Kang
- Department of Liver Diseases, Bethune International Peace Hospital, Shijiazhuang, Hebei, People's Republic of China
| | - Nan Sun
- Blood transfusion division, the Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Juan Wang
- Department of Orthopedics, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China
| | - Wei Chen
- Department of Orthopedics, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China
| | - Dong Li
- Department of Liver Diseases, Bethune International Peace Hospital, Shijiazhuang, Hebei, People's Republic of China
| | - Bao-En Shan
- Cancer Research Institute, the Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China.
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24
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Xiang JF, Liu L. Immune contexture and classification in human digestive malignant tumors: A novel way to evaluate tumors and impact on clinical outcome and therapy. Shijie Huaren Xiaohua Zazhi 2016; 24:3666-3672. [DOI: 10.11569/wcjd.v24.i25.3666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Digestive malignant tumors have become a major threat to human health. In recent years, the advances in surgical technique, radiation and chemotherapy strategies have greatly improved the prognosis of tumor patients. However, some patients are still unable to benefit from current treatments. The classification of tumors has relied on the molecular biological features of tumors more than histopathological characteristics. Analysis of the human immune microenvironment offers a novel paradigm by which the immune response affects clinical outcome. Immunotherapy may be a meaningful treatment in the development of novel cancer therapies.
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25
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DNA-based nanoparticle tension sensors reveal that T-cell receptors transmit defined pN forces to their antigens for enhanced fidelity. Proc Natl Acad Sci U S A 2016; 113:5610-5. [PMID: 27140637 DOI: 10.1073/pnas.1600163113] [Citation(s) in RCA: 218] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
T cells are triggered when the T-cell receptor (TCR) encounters its antigenic ligand, the peptide-major histocompatibility complex (pMHC), on the surface of antigen presenting cells (APCs). Because T cells are highly migratory and antigen recognition occurs at an intermembrane junction where the T cell physically contacts the APC, there are long-standing questions of whether T cells transmit defined forces to their TCR complex and whether chemomechanical coupling influences immune function. Here we develop DNA-based gold nanoparticle tension sensors to provide, to our knowledge, the first pN tension maps of individual TCR-pMHC complexes during T-cell activation. We show that naïve T cells harness cytoskeletal coupling to transmit 12-19 pN of force to their TCRs within seconds of ligand binding and preceding initial calcium signaling. CD8 coreceptor binding and lymphocyte-specific kinase signaling are required for antigen-mediated cell spreading and force generation. Lymphocyte function-associated antigen 1 (LFA-1) mediated adhesion modulates TCR-pMHC tension by intensifying its magnitude to values >19 pN and spatially reorganizes the location of TCR forces to the kinapse, the zone located at the trailing edge of migrating T cells, thus demonstrating chemomechanical crosstalk between TCR and LFA-1 receptor signaling. Finally, T cells display a dampened and poorly specific response to antigen agonists when TCR forces are chemically abolished or physically "filtered" to a level below ∼12 pN using mechanically labile DNA tethers. Therefore, we conclude that T cells tune TCR mechanics with pN resolution to create a checkpoint of agonist quality necessary for specific immune response.
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26
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Sauer MM, Jakob RP, Eras J, Baday S, Eriş D, Navarra G, Bernèche S, Ernst B, Maier T, Glockshuber R. Catch-bond mechanism of the bacterial adhesin FimH. Nat Commun 2016; 7:10738. [PMID: 26948702 PMCID: PMC4786642 DOI: 10.1038/ncomms10738] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 01/13/2016] [Indexed: 01/12/2023] Open
Abstract
Ligand–receptor interactions that are reinforced by mechanical stress, so-called catch-bonds, play a major role in cell–cell adhesion. They critically contribute to widespread urinary tract infections by pathogenic Escherichia coli strains. These pathogens attach to host epithelia via the adhesin FimH, a two-domain protein at the tip of type I pili recognizing terminal mannoses on epithelial glycoproteins. Here we establish peptide-complemented FimH as a model system for fimbrial FimH function. We reveal a three-state mechanism of FimH catch-bond formation based on crystal structures of all states, kinetic analysis of ligand interaction and molecular dynamics simulations. In the absence of tensile force, the FimH pilin domain allosterically accelerates spontaneous ligand dissociation from the FimH lectin domain by 100,000-fold, resulting in weak affinity. Separation of the FimH domains under stress abolishes allosteric interplay and increases the affinity of the lectin domain. Cell tracking demonstrates that rapid ligand dissociation from FimH supports motility of piliated E. coli on mannosylated surfaces in the absence of shear force. Catch bonds have a role in bacterial adhesion and infection by uropathogenic E. coli. Here, the authors report crystal structures, molecular dynamics simulations, ligand binding analysis and cell tracking to characterise the catch bond interaction between the adhesin FimH and carbohydrate receptors.
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Affiliation(s)
- Maximilian M Sauer
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH, Zurich, Otto-Stern-Weg 5, 8093 Zurich, Switzerland
| | - Roman P Jakob
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Jonathan Eras
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH, Zurich, Otto-Stern-Weg 5, 8093 Zurich, Switzerland
| | - Sefer Baday
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.,SIB Swiss Institute of Bioinformatics, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Deniz Eriş
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Giulio Navarra
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Simon Bernèche
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.,SIB Swiss Institute of Bioinformatics, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Beat Ernst
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Timm Maier
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Rudi Glockshuber
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH, Zurich, Otto-Stern-Weg 5, 8093 Zurich, Switzerland
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27
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Murray JS. An old Twist in HLA-A: CDR3α Hook up at an R65-joint. Front Immunol 2015; 6:268. [PMID: 26074926 PMCID: PMC4445401 DOI: 10.3389/fimmu.2015.00268] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/14/2015] [Indexed: 11/30/2022] Open
Abstract
T-cell ontogeny optimizes the α/β T-cell receptor (TCR) repertoire for recognition of major histocompatibility complex (MHC) class-I/II genetic polymorphism, and co-evolution of TCR germline V-gene segments and the MHC must entail somatic diversity generated in the third complimentary determining regions (CDR3α/β); however, it is still not clear how. Herein, a conspicuous structural link between the V-Jα used by several different TCR [all in complex with the same MHC molecule (HLA-A2)], and a conserved MHC motif (a.a., R65-X-X-K-A-X-S-Q72) is described. We model this R65-joint in detail, and show that the same TCR’s CDR3α loop maintains its CDR2α loop at a distance of ~4 Å from polymorphic amino acid (a.a.) positions of the α-2 helix in all but one of the analyzed crystal structures. Indeed, the pitch of docked TCRs varies as their twist/tilt/sway maintains the R65-joint and peptide contacts. Thus, the R65-joint appears to have poised the HLA-A lineage toward alloreactivity.
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Indoctrinating T cells to attack pathogens through homeschooling. Trends Immunol 2015; 36:337-43. [PMID: 25979654 DOI: 10.1016/j.it.2015.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/15/2015] [Accepted: 04/15/2015] [Indexed: 12/14/2022]
Abstract
Adaptive immunity is predicated on the ability of the T cell repertoire to have pre-existing specificity for the universe of potential pathogens. Recent findings suggest that T cell receptor (TCR)-self-major histocompatibility protein (pMHC) interactions limit autoimmune responses while enhancing T cell response to foreign antigens. We review these findings here, placing them in context of the current understanding of how TCR-self-pMHC interactions regulate T cell activation thresholds, and suggest that TCR-self-pMHC interactions increase the efficiency of the T cell repertoire by giving a competitive advantage to peptide cross-reactive T cells. We propose that self-reactivity and peptide cross-reactivity are controlled by particular CDR3 sequence motifs, which would allow thymic selection to contribute to solving the feat of broad pathogen specificity by exporting T cells that are pre-screened by positive and negative selection for the ability to be 'moderately' peptide cross-reactive.
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