1
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Lippert AH, Paluch C, Gaglioni M, Vuong MT, McColl J, Jenkins E, Fellermeyer M, Clarke J, Sharma S, Moreira da Silva S, Akkaya B, Anzilotti C, Morgan SH, Jessup CF, Körbel M, Gileadi U, Leitner J, Knox R, Chirifu M, Huo J, Yu S, Ashman N, Lui Y, Wilkinson I, Attfield KE, Fugger L, Robertson NJ, Lynch CJ, Murray L, Steinberger P, Santos AM, Lee SF, Cornall RJ, Klenerman D, Davis SJ. Antibody agonists trigger immune receptor signaling through local exclusion of receptor-type protein tyrosine phosphatases. Immunity 2024; 57:256-270.e10. [PMID: 38354703 DOI: 10.1016/j.immuni.2024.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/30/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024]
Abstract
Antibodies can block immune receptor engagement or trigger the receptor machinery to initiate signaling. We hypothesized that antibody agonists trigger signaling by sterically excluding large receptor-type protein tyrosine phosphatases (RPTPs) such as CD45 from sites of receptor engagement. An agonist targeting the costimulatory receptor CD28 produced signals that depended on antibody immobilization and were sensitive to the sizes of the receptor, the RPTPs, and the antibody itself. Although both the agonist and a non-agonistic anti-CD28 antibody locally excluded CD45, the agonistic antibody was more effective. An anti-PD-1 antibody that bound membrane proximally excluded CD45, triggered Src homology 2 domain-containing phosphatase 2 recruitment, and suppressed systemic lupus erythematosus and delayed-type hypersensitivity in experimental models. Paradoxically, nivolumab and pembrolizumab, anti-PD-1-blocking antibodies used clinically, also excluded CD45 and were agonistic in certain settings. Reducing these agonistic effects using antibody engineering improved PD-1 blockade. These findings establish a framework for developing new and improved therapies for autoimmunity and cancer.
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Affiliation(s)
- Anna H Lippert
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Christopher Paluch
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; Nuffield Department of Medicine, University of Oxford, Oxford, UK; MiroBio Ltd, Winchester House, Oxford Science Park, Oxford, UK
| | - Meike Gaglioni
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Mai T Vuong
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Edward Jenkins
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Martin Fellermeyer
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Joseph Clarke
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Sumana Sharma
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | | | - Billur Akkaya
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Consuelo Anzilotti
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sara H Morgan
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Claire F Jessup
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Markus Körbel
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Uzi Gileadi
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Judith Leitner
- Division of Immune Receptors and T cell Activation, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Rachel Knox
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Mami Chirifu
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Jiandong Huo
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Susan Yu
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Nicole Ashman
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Yuan Lui
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | | | - Kathrine E Attfield
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Oxford Centre for Neuroinflammation, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Lars Fugger
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Oxford Centre for Neuroinflammation, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | | | | | - Lynne Murray
- MiroBio Ltd, Winchester House, Oxford Science Park, Oxford, UK
| | - Peter Steinberger
- Division of Immune Receptors and T cell Activation, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Ana Mafalda Santos
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Richard J Cornall
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, UK.
| | - Simon J Davis
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK.
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Johnson RT, Solanki R, Wostear F, Ahmed S, Taylor JCK, Rees J, Abel G, McColl J, Jørgensen HF, Morris CJ, Bidula S, Warren DT. Piezo1-mediated regulation of smooth muscle cell volume in response to enhanced extracellular matrix rigidity. Br J Pharmacol 2023. [PMID: 38044463 DOI: 10.1111/bph.16294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 11/06/2023] [Accepted: 11/23/2023] [Indexed: 12/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Decreased aortic compliance is a precursor to numerous cardiovascular diseases. Compliance is regulated by the rigidity of the aortic wall and the vascular smooth muscle cells (VSMCs). Extracellular matrix stiffening, observed during ageing, reduces compliance. In response to increased rigidity, VSMCs generate enhanced contractile forces that result in VSMC stiffening and a further reduction in compliance. Mechanisms driving VSMC response to matrix rigidity remain poorly defined. EXPERIMENTAL APPROACH Human aortic-VSMCs were seeded onto polyacrylamide hydrogels whose rigidity mimicked either healthy (12 kPa) or aged/diseased (72 kPa) aortae. VSMCs were treated with pharmacological agents prior to agonist stimulation to identify regulators of VSMC volume regulation. KEY RESULTS On pliable matrices, VSMCs contracted and decreased in cell area. Meanwhile, on rigid matrices VSMCs displayed a hypertrophic-like response, increasing in area and volume. Piezo1 activation stimulated increased VSMC volume by promoting calcium ion influx and subsequent activation of PKC and aquaporin-1. Pharmacological blockade of this pathway prevented the enhanced VSMC volume response on rigid matrices whilst maintaining contractility on pliable matrices. Importantly, both piezo1 and aquaporin-1 gene expression were up-regulated during VSMC phenotypic modulation in atherosclerosis and after carotid ligation. CONCLUSIONS AND IMPLICATIONS In response to extracellular matrix rigidity, VSMC volume is increased by a piezo1/PKC/aquaporin-1 mediated pathway. Pharmacological targeting of this pathway specifically blocks the matrix rigidity enhanced VSMC volume response, leaving VSMC contractility on healthy mimicking matrices intact. Importantly, upregulation of both piezo1 and aquaporin-1 gene expression is observed in disease relevant VSMC phenotypes.
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Affiliation(s)
| | - Reesha Solanki
- School of Pharmacy, University of East Anglia, Norwich, UK
| | - Finn Wostear
- School of Pharmacy, University of East Anglia, Norwich, UK
| | - Sultan Ahmed
- School of Pharmacy, University of East Anglia, Norwich, UK
| | - James C K Taylor
- Section of Cardiorespiratory Medicine, University of Cambridge, VPD Heart and Lung Research Institute, Cambridge, UK
| | - Jasmine Rees
- School of Pharmacy, University of East Anglia, Norwich, UK
| | - Geraad Abel
- School of Pharmacy, University of East Anglia, Norwich, UK
| | - James McColl
- Henry Wellcome Laboratory for Cell Imaging, University of East Anglia, Norfolk, UK
| | - Helle F Jørgensen
- Section of Cardiorespiratory Medicine, University of Cambridge, VPD Heart and Lung Research Institute, Cambridge, UK
| | - Chris J Morris
- School of Pharmacy, University College London, London, UK
| | - Stefan Bidula
- School of Pharmacy, University of East Anglia, Norwich, UK
| | - Derek T Warren
- School of Pharmacy, University of East Anglia, Norwich, UK
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3
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Jenkins E, Körbel M, O'Brien-Ball C, McColl J, Chen KY, Kotowski M, Humphrey J, Lippert AH, Brouwer H, Santos AM, Lee SF, Davis SJ, Klenerman D. Antigen discrimination by T cells relies on size-constrained microvillar contact. Nat Commun 2023; 14:1611. [PMID: 36959206 PMCID: PMC10036606 DOI: 10.1038/s41467-023-36855-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 02/21/2023] [Indexed: 03/25/2023] Open
Abstract
T cells use finger-like protrusions called 'microvilli' to interrogate their targets, but why they do so is unknown. To form contacts, T cells must overcome the highly charged, barrier-like layer of large molecules forming a target cell's glycocalyx. Here, T cells are observed to use microvilli to breach a model glycocalyx barrier, forming numerous small (<0.5 μm diameter) contacts each of which is stabilized by the small adhesive protein CD2 expressed by the T cell, and excludes large proteins including CD45, allowing sensitive, antigen dependent TCR signaling. In the absence of the glycocalyx or when microvillar contact-size is increased by enhancing CD2 expression, strong signaling occurs that is no longer antigen dependent. Our observations suggest that, modulated by the opposing effects of the target cell glycocalyx and small adhesive proteins, the use of microvilli equips T cells with the ability to effect discriminatory receptor signaling.
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Affiliation(s)
- Edward Jenkins
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Markus Körbel
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Caitlin O'Brien-Ball
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - James McColl
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Kevin Y Chen
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Mateusz Kotowski
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Jane Humphrey
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Anna H Lippert
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Heather Brouwer
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Ana Mafalda Santos
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Steven F Lee
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Simon J Davis
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK.
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK.
| | - David Klenerman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
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4
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McColl J, Klenerman D. Surfaces for Study of Receptor Dynamics on T Cells. Methods Mol Biol 2023; 2654:41-50. [PMID: 37106174 DOI: 10.1007/978-1-0716-3135-5_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Microscopy developments since the turn of the decade have seen an abundance of imaging modalities emerge that are revolutionizing the way we image the immune system. We are now able to image faster and utilize techniques that can image individual receptors, in real time, on live T cells. Total internal reflection fluorescence (TIRF) microscopy is one such technique, although it has one problem. The imaging must be carried out close to the glass interface. There are clearly issues with live cell imaging at glass surfaces as these are not biologically relevant. Manipulating the surface is key for maintaining biologically relevant imaging conditions. Here, we describe a simple approach to generate substrates for cell attachment and imaging of receptor dynamics and outline a guide for imaging and tracking T cell, surface receptors using TIRF microscopy.
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Affiliation(s)
- James McColl
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, UK.
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5
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Sanders EW, Carr AR, Bruggeman E, Körbel M, Benaissa SI, Donat RF, Santos AM, McColl J, O'Holleran K, Klenerman D, Davis SJ, Lee SF, Ponjavic A. resPAINT: Accelerating Volumetric Super-Resolution Localisation Microscopy by Active Control of Probe Emission. Angew Chem Int Ed Engl 2022; 61:e202206919. [PMID: 35876263 DOI: 10.1002/anie.202206919] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Indexed: 01/07/2023]
Abstract
Points for accumulation in nanoscale topography (PAINT) allows practically unlimited measurements in localisation microscopy but is limited by background fluorescence at high probe concentrations, especially in volumetric imaging. We present reservoir-PAINT (resPAINT), which combines PAINT and active control of probe photophysics. In resPAINT, an activatable probe "reservoir" accumulates on target, enabling a 50-fold increase in localisation rate versus conventional PAINT, without compromising contrast. By combining resPAINT with large depth-of-field microscopy, we demonstrate super-resolution imaging of entire cell surfaces. We generalise the approach by implementing various switching strategies and 3D imaging techniques. Finally, we use resPAINT with a Fab to image membrane proteins, extending the operating regime of PAINT to include a wider range of biological interactions.
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Affiliation(s)
- Edward W Sanders
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Alexander R Carr
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Ezra Bruggeman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Markus Körbel
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Sarah I Benaissa
- Cambridge Advanced Imaging Centre, University of Cambridge, Cambridge, CB2 3DY, UK
| | - Robert F Donat
- Radcliffe Department of Medicine and United Kingdom Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Ana M Santos
- Radcliffe Department of Medicine and United Kingdom Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - James McColl
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Kevin O'Holleran
- Cambridge Advanced Imaging Centre, University of Cambridge, Cambridge, CB2 3DY, UK
| | - David Klenerman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Simon J Davis
- Radcliffe Department of Medicine and United Kingdom Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Steven F Lee
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Aleks Ponjavic
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.,School of Physics and Astronomy, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.,School of Food Science and Nutrition, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
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6
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Sanders EW, Carr AR, Bruggeman E, Körbel M, Benaissa SI, Donat RF, Santos AM, McColl J, O'Holleran K, Klenerman D, Davis SJ, Lee SF, Ponjavic A. resPAINT: Accelerating Volumetric Super-Resolution Localisation Microscopy by Active Control of Probe Emission. Angew Chem Weinheim Bergstr Ger 2022; 134:e202206919. [PMID: 38505515 PMCID: PMC10946633 DOI: 10.1002/ange.202206919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Indexed: 03/21/2024]
Abstract
Points for accumulation in nanoscale topography (PAINT) allows practically unlimited measurements in localisation microscopy but is limited by background fluorescence at high probe concentrations, especially in volumetric imaging. We present reservoir-PAINT (resPAINT), which combines PAINT and active control of probe photophysics. In resPAINT, an activatable probe "reservoir" accumulates on target, enabling a 50-fold increase in localisation rate versus conventional PAINT, without compromising contrast. By combining resPAINT with large depth-of-field microscopy, we demonstrate super-resolution imaging of entire cell surfaces. We generalise the approach by implementing various switching strategies and 3D imaging techniques. Finally, we use resPAINT with a Fab to image membrane proteins, extending the operating regime of PAINT to include a wider range of biological interactions.
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Affiliation(s)
- Edward W. Sanders
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Alexander R. Carr
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Ezra Bruggeman
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Markus Körbel
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Sarah I. Benaissa
- Cambridge Advanced Imaging CentreUniversity of CambridgeCambridgeCB2 3DYUK
| | - Robert F. Donat
- Radcliffe Department of Medicine and United Kingdom Medical Research Council Human Immunology UnitJohn Radcliffe HospitalUniversity of OxfordOxfordOX3 9DSUK
| | - Ana M. Santos
- Radcliffe Department of Medicine and United Kingdom Medical Research Council Human Immunology UnitJohn Radcliffe HospitalUniversity of OxfordOxfordOX3 9DSUK
| | - James McColl
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Kevin O'Holleran
- Cambridge Advanced Imaging CentreUniversity of CambridgeCambridgeCB2 3DYUK
| | - David Klenerman
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Simon J. Davis
- Radcliffe Department of Medicine and United Kingdom Medical Research Council Human Immunology UnitJohn Radcliffe HospitalUniversity of OxfordOxfordOX3 9DSUK
| | - Steven F. Lee
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Aleks Ponjavic
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
- School of Physics and AstronomyUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUK
- School of Food Science and NutritionUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUK
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7
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Lippert AH, Dimov IB, Winkel AK, Humphrey J, McColl J, Chen KY, Santos AM, Jenkins E, Franze K, Davis SJ, Klenerman D. Soft Polydimethylsiloxane-Supported Lipid Bilayers for Studying T Cell Interactions. Biophys J 2021; 120:35-45. [PMID: 33248128 PMCID: PMC7820804 DOI: 10.1016/j.bpj.2020.11.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/22/2020] [Accepted: 11/17/2020] [Indexed: 12/23/2022] Open
Abstract
Much of what we know about the early stages of T cell activation has been obtained from studies of T cells interacting with glass-supported lipid bilayers that favor imaging but are orders of magnitude stiffer than typical cells. We developed a method for attaching lipid bilayers to polydimethylsiloxane polymer supports, producing "soft bilayers" with physiological levels of mechanical resistance (Young's modulus of 4 kPa). Comparisons of T cell behavior on soft and glass-supported bilayers revealed that whereas late stages of T cell activation are thought to be substrate-stiffness dependent, early calcium signaling was unaffected by substrate rigidity, implying that early steps in T cell receptor triggering are not mechanosensitive. The exclusion of large receptor-type phosphatases was observed on the soft bilayers, however, even though it is yet to be demonstrated at authentic cell-cell contacts. This work sets the stage for an imaging-based exploration of receptor signaling under conditions closely mimicking physiological cell-cell contact.
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Affiliation(s)
- Anna H Lippert
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
| | - Ivan B Dimov
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Alexander K Winkel
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Jane Humphrey
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Kevin Y Chen
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ana M Santos
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Edward Jenkins
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Simon J Davis
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
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8
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Spark A, Kitching A, Esteban-Ferrer D, Handa A, Carr AR, Needham LM, Ponjavic A, Santos AM, McColl J, Leterrier C, Davis SJ, Henriques R, Lee SF. vLUME: 3D virtual reality for single-molecule localization microscopy. Nat Methods 2020; 17:1097-1099. [PMID: 33046895 PMCID: PMC7612967 DOI: 10.1038/s41592-020-0962-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022]
Abstract
vLUME is a virtual reality software package designed to render large three-dimensional single-molecule localization microscopy datasets. vLUME features include visualization, segmentation, bespoke analysis of complex local geometries and exporting features. vLUME can perform complex analysis on real three-dimensional biological samples that would otherwise be impossible by using regular flat-screen visualization programs.
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Affiliation(s)
| | | | | | - Anoushka Handa
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | | | - Aleks Ponjavic
- School of Physics and Astronomy, University of Leeds, Leeds, UK
- School of Food Science and Nutrition, University of Leeds, Leeds, UK
| | - Ana Mafalda Santos
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | - Simon J Davis
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Ricardo Henriques
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, UK.
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9
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Kulenkampff K, Lippert AH, McColl J, Santos AM, Ponjavic A, Jenkins E, Humphrey J, Winkel A, Franze K, Lee SF, Davis SJ, Klenerman D. The Costs of Close Contacts: Visualizing the Energy Landscape of Cell Contacts at the Nanoscale. Biophys J 2020; 118:1261-1269. [PMID: 32075748 PMCID: PMC7091464 DOI: 10.1016/j.bpj.2020.01.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 12/27/2022] Open
Abstract
Cell-cell contacts often underpin signaling between cells. For immunology, the binding of a T cell receptor to an antigen-presenting pMHC initiates downstream signaling and an immune response. Although this contact is mediated by proteins on both cells creating interfaces with gap sizes typically around 14 nm, many, often contradictory observations have been made regarding the influence of the contact on parameters such as the binding kinetics, spatial distribution, and diffusion of signaling proteins within the contact. Understanding the basic physical constraints on probes inside this crowded environment will help inform studies on binding kinetics and dynamics of signaling of relevant proteins in the synapse. By tracking quantum dots of different dimensions for extended periods of time, we have shown that it is possible to obtain the probability of a molecule entering the contact, the change in its diffusion upon entry, and the impact of spatial heterogeneity of adhesion protein density in the contact. By analyzing the contacts formed by a T cell interacting with adhesion proteins anchored to a supported lipid bilayer, we find that probes are excluded from contact entry in a size-dependent manner for gap-to-probe differences of 4.1 nm. We also observed probes being trapped inside the contact and a decrease in diffusion of up to 85% in dense adhesion protein contacts. This approach provides new, to our knowledge, insights into the nature of cell-cell contacts, revealing that cell contacts are highly heterogeneous because of topography- and protein-density-related processes. These effects are likely to profoundly influence signaling between cells.
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Affiliation(s)
- Klara Kulenkampff
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Anna H Lippert
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ana Mafalda Santos
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Aleks Ponjavic
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Edward Jenkins
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Jane Humphrey
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Alexander Winkel
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Simon J Davis
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
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10
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Wright CM, Marryat L, McColl J, Harjunmaa U, Cole TJ. Pathways into and out of overweight and obesity from infancy to mid-childhood. Pediatr Obes 2018; 13:621-627. [PMID: 29998577 PMCID: PMC6220864 DOI: 10.1111/ijpo.12427] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/13/2018] [Accepted: 04/24/2018] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To investigate whether high weight in infancy predicts obesity in childhood. METHOD Data from two UK cohorts (Newcastle Growth and Development N = 795, Gateshead Millennium N = 393) and one Finnish (Tampere N = 1262) were combined. Z scores of weight at 3 and 12 months and body mass index (BMI) at 5 and 8 years were categorized as raised/overweight (1 to <2 SD) or high/obese (≥2 SD). RESULTS The majority of infants with raised or high weight at birth tended to revert to normal by 3 months and to track in the same category from 3 to 12 months. Although infants with high weight were five times more likely to have BMI ≥ 2 SD at 8 years (p < 0.001), only 22% went on to have BMI ≥ 2 SD, while 64% of infants with raised weight had normal BMI at 8 years. Of children with BMI ≥ 2 SD aged 8 years, only 22% had raised weight in infancy and half had BMI ≥ 2 SD for the first time at that age. CONCLUSIONS Infants with raised weight in infancy tend to remain so, but most children who go on to have BMI ≥ 2 SD were not unusually heavy infants and the majority of infants with high weight reverted to overweight or normal weight in childhood.
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Affiliation(s)
- C. M. Wright
- School of Medicine, College of MVLSUniversity of GlasgowGlasgowUK
| | - L. Marryat
- School of Mathematics and StatisticsUniversity of GlasgowGlasgowUK
- Farr Institute @ Scotland/Scottish Collaboration for Public Health Research and PolicyUniversity of EdinburghEdinburghUK
| | - J. McColl
- School of Mathematics and StatisticsUniversity of GlasgowGlasgowUK
| | - U. Harjunmaa
- Center for Child Health ResearchUniversity of Tampere Faculty of Medicine and Life Sciences, and Tampere University HospitalTampereFinland
| | - T. J. Cole
- Population, Policy and Practice ProgrammeUCL Great Ormond Street Institute of Child HealthLondonUK
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11
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McColl J, Mok GF, Lippert AH, Ponjavic A, Muresan L, Münsterberg A. 4D imaging reveals stage dependent random and directed cell motion during somite morphogenesis. Sci Rep 2018; 8:12644. [PMID: 30139994 PMCID: PMC6107556 DOI: 10.1038/s41598-018-31014-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 08/10/2018] [Indexed: 12/26/2022] Open
Abstract
Somites are paired embryonic segments that form in a regular sequence from unsegmented mesoderm during vertebrate development. Although transient structures they are of fundamental importance as they generate cell lineages of the musculoskeletal system in the trunk such as cartilage, tendon, bone, endothelial cells and skeletal muscle. Surprisingly, very little is known about cellular dynamics underlying the morphological transitions during somite differentiation. Here, we address this by examining cellular rearrangements and morphogenesis in differentiating somites using live multi-photon imaging of transgenic chick embryos, where all cells express a membrane-bound GFP. We specifically focussed on the dynamic cellular changes in two principle regions within the somite, the medial and lateral domains, to investigate extensive morphological transformations. Furthermore, by using quantitative analysis and cell tracking, we capture for the first time a directed movement of dermomyotomal progenitor cells towards the rostro-medial domain of the dermomyotome, where skeletal muscle formation initiates.
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Affiliation(s)
- James McColl
- 0000 0001 1092 7967grid.8273.eSchool of Biological Sciences, Cell and Developmental Biology, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ UK ,0000000121885934grid.5335.0Chemistry Department, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
| | - Gi Fay Mok
- 0000 0001 1092 7967grid.8273.eSchool of Biological Sciences, Cell and Developmental Biology, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ UK
| | - Anna H. Lippert
- 0000000121885934grid.5335.0Chemistry Department, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
| | - Aleks Ponjavic
- 0000000121885934grid.5335.0Chemistry Department, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
| | - Leila Muresan
- Cambridge Advanced Imaging Centre (CAIC), Downing Street, Cambridge, CB2 3DY UK
| | - Andrea Münsterberg
- 0000 0001 1092 7967grid.8273.eSchool of Biological Sciences, Cell and Developmental Biology, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ UK
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12
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McCallum R, McColl J, Iyer A. The effect of light intensity on image quality in endoscopic ear surgery. Clin Otolaryngol 2018; 43:1266-1272. [DOI: 10.1111/coa.13139] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2018] [Indexed: 11/28/2022]
Affiliation(s)
- R. McCallum
- Department of Otolaryngology; Monklands Hospital; Airdrie Scotland
| | - J. McColl
- School of Mathematics and Statistics; University of Glasgow; Glasgow Scotland
| | - A. Iyer
- Department of Otolaryngology; Monklands Hospital; Airdrie Scotland
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13
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Ponjavic A, McColl J, Carr AR, Santos AM, Kulenkampff K, Lippert A, Davis SJ, Klenerman D, Lee SF. Single-Molecule Light-Sheet Imaging of Suspended T Cells. Biophys J 2018; 114:2200-2211. [PMID: 29742413 PMCID: PMC5961759 DOI: 10.1016/j.bpj.2018.02.044] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 11/26/2022] Open
Abstract
Adaptive immune responses are initiated by triggering of the T cell receptor. Single-molecule imaging based on total internal reflection fluorescence microscopy at coverslip/basal cell interfaces is commonly used to study this process. These experiments have suggested, unexpectedly, that the diffusional behavior and organization of signaling proteins and receptors may be constrained before activation. However, it is unclear to what extent the molecular behavior and cell state is affected by the imaging conditions, i.e., by the presence of a supporting surface. In this study, we implemented single-molecule light-sheet microscopy, which enables single receptors to be directly visualized at any plane in a cell to study protein dynamics and organization in live, resting T cells. The light sheet enabled the acquisition of high-quality single-molecule fluorescence images that were comparable to those of total internal reflection fluorescence microscopy. By comparing the apical and basal surfaces of surface-contacting T cells using single-molecule light-sheet microscopy, we found that most coated-glass surfaces and supported lipid bilayers profoundly affected the diffusion of membrane proteins (T cell receptor and CD45) and that all the surfaces induced calcium influx to various degrees. Our results suggest that, when studying resting T cells, surfaces are best avoided, which we achieve here by suspending cells in agarose.
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Affiliation(s)
- Aleks Ponjavic
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Alexander R Carr
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ana Mafalda Santos
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Klara Kulenkampff
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Anna Lippert
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Simon J Davis
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom.
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
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14
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Santos AM, Ponjavic A, Fritzsche M, Fernandes RA, de la Serna JB, Wilcock MJ, Schneider F, Urbančič I, McColl J, Anzilotti C, Ganzinger KA, Aßmann M, Depoil D, Cornall RJ, Dustin ML, Klenerman D, Davis SJ, Eggeling C, Lee SF. Capturing resting T cells: the perils of PLL. Nat Immunol 2018; 19:203-205. [PMID: 29476188 PMCID: PMC7612954 DOI: 10.1038/s41590-018-0048-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 12/13/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Ana Mafalda Santos
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Aleks Ponjavic
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Marco Fritzsche
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - Ricardo A Fernandes
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Jorge Bernardino de la Serna
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Martin J Wilcock
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Falk Schneider
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Iztok Urbančič
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Consuelo Anzilotti
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | | | - Meike Aßmann
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - David Depoil
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - Richard J Cornall
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Simon J Davis
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Christian Eggeling
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK.
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, UK.
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15
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Mok GF, McColl J, Lippert A, Ponjavic A, Muresan L, Münsterberg A. 4D visualisation and analysis of somite morphogenesis in live embryos using multi-photon microscopy. Mech Dev 2017. [DOI: 10.1016/j.mod.2017.04.164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Carr AR, Ponjavic A, Basu S, McColl J, Santos AM, Davis S, Laue ED, Klenerman D, Lee SF. Three-Dimensional Super-Resolution in Eukaryotic Cells Using the Double-Helix Point Spread Function. Biophys J 2017; 112:1444-1454. [PMID: 28402886 PMCID: PMC5390298 DOI: 10.1016/j.bpj.2017.02.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/07/2017] [Accepted: 02/21/2017] [Indexed: 02/02/2023] Open
Abstract
Single-molecule localization microscopy, typically based on total internal reflection illumination, has taken our understanding of protein organization and dynamics in cells beyond the diffraction limit. However, biological systems exist in a complicated three-dimensional environment, which has required the development of new techniques, including the double-helix point spread function (DHPSF), to accurately visualize biological processes. The application of the DHPSF approach has so far been limited to the study of relatively small prokaryotic cells. By matching the refractive index of the objective lens immersion liquid to that of the sample media, we demonstrate DHPSF imaging of up to 15-μm-thick whole eukaryotic cell volumes in three to five imaging planes. We illustrate the capabilities of the DHPSF by exploring large-scale membrane reorganization in human T cells after receptor triggering, and by using single-particle tracking to image several mammalian proteins, including membrane, cytoplasmic, and nuclear proteins in T cells and embryonic stem cells.
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Affiliation(s)
- Alexander R. Carr
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Aleks Ponjavic
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Srinjan Basu
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ana Mafalda Santos
- Radcliffe Department of Clinical Medicine and Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Simon Davis
- Radcliffe Department of Clinical Medicine and Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Ernest D. Laue
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Steven F. Lee
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom,Corresponding author
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17
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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: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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Ganzinger KA, Narayan P, Qamar SS, Weimann L, Ranasinghe RT, Aguzzi A, Dobson CM, McColl J, St George-Hyslop P, Klenerman D. Single-molecule imaging reveals that small amyloid-β1-42 oligomers interact with the cellular prion protein (PrP(C)). Chembiochem 2014; 15:2515-21. [PMID: 25294384 PMCID: PMC4371635 DOI: 10.1002/cbic.201402377] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Indexed: 12/17/2022]
Abstract
Oligomers of the amyloid-β peptide (Aβ) play a central role in the pathogenesis of Alzheimer’s disease and have been suggested to induce neurotoxicity by binding to a plethora of cell-surface receptors. However, the heterogeneous mixtures of oligomers of varying sizes and conformations formed by Aβ42 have obscured the nature of the oligomeric species that bind to a given receptor. Here, we have used single-molecule imaging to characterize Aβ42 oligomers (oAβ42) and to confirm the controversial interaction of oAβ42 with the cellular prion protein (PrPC) on live neuronal cells. Our results show that, at nanomolar concentrations, oAβ42 interacts with PrPC and that the species bound to PrPC are predominantly small oligomers (dimers and trimers). Single-molecule biophysical studies can thus aid in deciphering the mechanisms that underlie receptor-mediated oAβ-induced neurotoxicity, and ultimately facilitate the discovery of novel inhibitors of these pathways.
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Affiliation(s)
- Kristina A Ganzinger
- Department of Chemistry, University of CambridgeLensfield Road, Cambridge, CB2 1EW (UK)
| | - Priyanka Narayan
- Present address: Whitehead Institute for Biomedical Research9 Cambridge Center, Cambridge, MA 02142 (USA)
| | - Seema S Qamar
- Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of CambridgeCambridge CB2 0XY (UK)
| | - Laura Weimann
- Department of Chemistry, University of CambridgeLensfield Road, Cambridge, CB2 1EW (UK)
| | - Rohan T Ranasinghe
- Department of Chemistry, University of CambridgeLensfield Road, Cambridge, CB2 1EW (UK)
| | - Adriano Aguzzi
- UniversitätsSpital Zürich, Institut für NeuropathologieSchmelzbergstrasse 12, 8091 Zürich (Switzerland)
| | - Christopher M Dobson
- Department of Chemistry, University of CambridgeLensfield Road, Cambridge, CB2 1EW (UK)
| | - James McColl
- Present address: School of Biological Sciences, University of East AngliaNorwich Research Park, Norwich NR4 7TJ (UK)
- James McColl, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW (UK), Peter St. George-Hyslop, Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY (UK), David Klenerman, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW (UK) E-mail: E-mail:
| | - Peter St George-Hyslop
- Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of CambridgeCambridge CB2 0XY (UK)
- James McColl, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW (UK), Peter St. George-Hyslop, Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY (UK), David Klenerman, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW (UK) E-mail: E-mail:
| | - David Klenerman
- Department of Chemistry, University of CambridgeLensfield Road, Cambridge, CB2 1EW (UK)
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19
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Lando D, Endesfelder U, Berger H, Subramanian L, Dunne PD, McColl J, Klenerman D, Carr AM, Sauer M, Allshire RC, Heilemann M, Laue ED. Quantitative single-molecule microscopy reveals that CENP-A(Cnp1) deposition occurs during G2 in fission yeast. Open Biol 2013; 2:120078. [PMID: 22870388 PMCID: PMC3411111 DOI: 10.1098/rsob.120078] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 06/08/2012] [Indexed: 11/30/2022] Open
Abstract
The inheritance of the histone H3 variant CENP-A in nucleosomes at centromeres following DNA replication is mediated by an epigenetic mechanism. To understand the process of epigenetic inheritance, or propagation of histones and histone variants, as nucleosomes are disassembled and reassembled in living eukaryotic cells, we have explored the feasibility of exploiting photo-activated localization microscopy (PALM). PALM of single molecules in living cells has the potential to reveal new concepts in cell biology, providing insights into stochastic variation in cellular states. However, thus far, its use has been limited to studies in bacteria or to processes occurring near the surface of eukaryotic cells. With PALM, one literally observes and ‘counts’ individual molecules in cells one-by-one and this allows the recording of images with a resolution higher than that determined by the diffraction of light (the so-called super-resolution microscopy). Here, we investigate the use of different fluorophores and develop procedures to count the centromere-specific histone H3 variant CENP-ACnp1 with single-molecule sensitivity in fission yeast (Schizosaccharomyces pombe). The results obtained are validated by and compared with ChIP-seq analyses. Using this approach, CENP-ACnp1 levels at fission yeast (S. pombe) centromeres were followed as they change during the cell cycle. Our measurements show that CENP-ACnp1 is deposited solely during the G2 phase of the cell cycle.
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Affiliation(s)
- David Lando
- Department of Biochemistry, University of Cambridge , Cambridge CB2 1EW, UK
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20
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Narayan P, Ganzinger KA, McColl J, Weimann L, Meehan S, Qamar S, Carver JA, Wilson MR, St. George-Hyslop P, Dobson CM, Klenerman D. Single molecule characterization of the interactions between amyloid-β peptides and the membranes of hippocampal cells. J Am Chem Soc 2013; 135:1491-8. [PMID: 23339742 PMCID: PMC3561772 DOI: 10.1021/ja3103567] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Indexed: 12/22/2022]
Abstract
Oligomers of the 40 and 42 residue amyloid-β peptides (Aβ40 and Aβ42) have been implicated in the neuronal damage and impaired cognitive function associated with Alzheimer's disease. However, little is known about the specific mechanisms by which these misfolded species induce such detrimental effects on cells. In this work, we use single-molecule imaging techniques to examine the initial interactions between Aβ monomers and oligomers and the membranes of live cells. This highly sensitive method enables the visualization of individual Aβ species on the cell surface and characterization of their oligomerization state, all at biologically relevant, nanomolar concentrations. The results indicate that oligomers preferentially interact with cell membranes, relative to monomers and that the oligomers become immobilized on the cell surface. Additionally, we observe that the interaction of Aβ species with the cell membrane is inhibited by the presence of ATP-independent molecular chaperones. This study demonstrates the power of this methodology for characterizing the interactions between protein aggregates and the membranes of live neuronal cells at physiologically relevant concentrations and opens the door to quantitative studies of the cellular responses to potentially pathogenic oligomers.
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Affiliation(s)
- Priyanka Narayan
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge,
United Kingdom CB2 1EW
| | - Kristina A. Ganzinger
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge,
United Kingdom CB2 1EW
| | - James McColl
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge,
United Kingdom CB2 1EW
| | - Laura Weimann
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge,
United Kingdom CB2 1EW
| | - Sarah Meehan
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge,
United Kingdom CB2 1EW
| | - Seema Qamar
- Cambridge Institute
for Medical Research, Wellcome Trust/MRC Building, Addenbrooke’s
Hospital, Hills Road, Cambridge, United Kingdom CB2 0XY
| | - John A. Carver
- School of Chemistry and
Physics, University of Adelaide, Adelaide,
South Australia 5005, Australia
| | - Mark R. Wilson
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales
2522, Australia
| | - Peter St. George-Hyslop
- Cambridge Institute
for Medical Research, Wellcome Trust/MRC Building, Addenbrooke’s
Hospital, Hills Road, Cambridge, United Kingdom CB2 0XY
| | - Christopher M. Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge,
United Kingdom CB2 1EW
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge,
United Kingdom CB2 1EW
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Lee SF, Klenerman D, Ganzinger K, Chang V, McColl J, Palayret M. Super-Resolution Imaging of T Cell Triggering Supports the Kinetic Segregation Model in the Adaptive Immune Response. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.2382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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22
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Abstract
In this work we show how hydrodynamic forces can be used to locally trap molecules in a supported lipid bilayer (SLB). The method uses the hydrodynamic drag forces arising from a flow through a conical pipette with a tip radius of 1-1.5 μm, placed approximately 1 μm above the investigated SLB. This results in a localized forcefield that acts on molecules protruding from the SLB, yielding a hydrodynamic trap with a size approximately given by the size of the pipette tip. We demonstrate this concept by trapping the protein streptavidin, bound to biotin receptors in the SLB. It is also shown how static and kinetic information about the intermolecular interactions in the lipid bilayer can be obtained by relating how the magnitude of the hydrodynamic forces affects the accumulation of protein molecules in the trap.
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Affiliation(s)
- Peter Jönsson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; and
| | - James McColl
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; and
| | - Richard W. Clarke
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; and
| | - Victor P. Ostanin
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; and
| | - Bengt Jönsson
- Department of Biophysical Chemistry, Lund University, SE-22100 Lund, Sweden
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; and
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Narayan P, Ganzinger KA, McColl J, Drews A, Clarke RW, Qamar S, George-Hyslop PS, Klenerman D. Investigating the Interaction Between Characterized Amyloid-Beta Oligomers and the Prion Protein Receptor in Live Cells. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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James JR, McColl J, Oliveira MI, Dunne PD, Huang E, Jansson A, Nilsson P, Sleep DL, Gonçalves CM, Morgan SH, Felce JH, Mahen R, Fernandes RA, Carmo AM, Klenerman D, Davis SJ. The T cell receptor triggering apparatus is composed of monovalent or monomeric proteins. J Biol Chem 2011; 286:31993-2001. [PMID: 21757710 PMCID: PMC3173209 DOI: 10.1074/jbc.m111.219212] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Understanding the component stoichiometry of the T cell antigen receptor (TCR) triggering apparatus is essential for building realistic models of signal initiation. Recent studies suggesting that the TCR and other signaling-associated proteins are preclustered on resting T cells relied on measurements of the behavior of membrane proteins at interfaces with functionalized glass surfaces. Using fluorescence recovery after photobleaching, we show that, compared with the apical surface, the mobility of TCRs is significantly reduced at Jurkat T cell/glass interfaces, in a signaling-sensitive manner. Using two biophysical approaches that mitigate these effects, bioluminescence resonance energy transfer and two-color coincidence detection microscopy, we show that, within the uncertainty of the methods, the membrane components of the TCR triggering apparatus, i.e. the TCR complex, MHC molecules, CD4/Lck and CD45, are exclusively monovalent or monomeric in human T cell lines, implying that TCR triggering depends only on the kinetics of TCR/pMHC interactions. These analyses also showed that constraining proteins to two dimensions at the cell surface greatly enhances random interactions versus those between the membrane and the cytoplasm. Simulations of TCR-pMHC complex formation based on these findings suggest how unclustered TCR triggering-associated proteins might nevertheless be capable of generating complex signaling outputs via the differential recruitment of cytosolic effectors to the cell membrane.
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Affiliation(s)
- John R James
- Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
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Dunne PD, Fernandes RA, McColl J, Yoon JW, James JR, Davis SJ, Klenerman D. DySCo: quantitating associations of membrane proteins using two-color single-molecule tracking. Biophys J 2009; 97:L5-7. [PMID: 19686638 PMCID: PMC2726305 DOI: 10.1016/j.bpj.2009.05.046] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 05/13/2009] [Accepted: 05/28/2009] [Indexed: 12/02/2022] Open
Abstract
We present a general method called dynamic single-molecule colocalization for quantitating the associations of single cell surface molecules labeled with distinct autofluorescent proteins. The chief advantages of the new quantitative approach are that, in addition to stable interactions, it is capable of measuring nonconstitutive associations, such as those induced by the cytoskeleton, and it is applicable to situations where the number of molecules is small.
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McColl J, Horvath R, Aref A, Larcombe L, Chianella I, Morgan S, Yakubov GE, Ramsden JJ. Polyphenol control of cell spreading on glycoprotein substrata. J Biomater Sci Polym Ed 2009; 20:841-51. [PMID: 19323893 DOI: 10.1163/156856209x427023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cell-surface contacts are vital for many eukaryotic cells. The surface provides anchorage (facilitating spreading and proliferation), is involved in sensation, i.e., via mechano-, osmo- and chemoreceptors, and in addition nutrients may also be supplied via vessels adjacent to the basal lamina. Hence, the ability to manipulate the surface characteristics provides a mechanism for directly influencing cell behaviour. Applications such as medical implants and tissue engineering require biocompatible, stable surfaces for controlling cell behaviour. Mucin-coated surfaces inhibit cell spreading compared with poly(L-lysine) in vitro; here, we show that a composite layer assembled from mucin-EGCg aggregates counters the inhibition. Although the anti-spreading effects of the glycoprotein substratum on cell behaviour are similar to those observed for pure polysaccharide surfaces, the reversal of cell spreading inhibition by the admixture of polyphenol/glycoprotein substrata is remarkable and unexpected. Possible applications for a composite glycoprotein-polyphenol layer include medical devices, in particular for those operating at mucosal interfaces such as the oral, tracheal or gastrointestinal tract cavities, wound healing, cancer control and the controlled growth of therapeutic cell cultures.
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Affiliation(s)
- James McColl
- Nanotechnology Centre, Cranfield University, Cranfield MK43 0AL, Bedfordshire, UK.
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27
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Abstract
The lubricating behavior of the weakly charged short-side-chain glycoprotein mucin "Orthana" (Mw=0.55 MDa) has been investigated between hydrophobic and hydrophilic PDMS substrates using soft-contact tribometry. It was found that mucin facilitates lubrication between hydrophobic PDMS surfaces, leading to a 10-fold reduction in boundary friction coefficient for rough surfaces. The presence of mucin also results in a shift of the mixed lubrication regime to lower entrainment speeds. The observed boundary lubrication behavior of mucin was found to depend on the bulk concentration, and we linked this to the structure and dynamics of the adsorbed mucin films, which are assessed using optical waveguide light spectroscopy. We observe a composite structure of the adsorbed mucin layer, with its internal structure governed by entanglement. The film thickness of this adsorbed layer increases with concentration, while the boundary friction coefficient for rough surfaces was found to be inversely proportional to the thickness of the adsorbed film. This link between lubrication and structure of the film is consistent with a viscous boundary lubrication mechanism, i.e., a thicker adsorbed film, at a given sliding speed, results in a lower local shear rate and, hence, in a lower local shear stress. The estimated local viscosities of the adsorbed layer, derived from the friction measurements and the polymer layer density, are in agreement with each other.
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Affiliation(s)
- Gleb E Yakubov
- Unilever Corporate Research, Colworth Science Park, Bedfordshire MK44 1LQ, UK.
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28
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Abstract
Modulation of the coupling of light into a waveguide via a grating, together with a novel approach to analyzing the data, is used to investigate the attachment of human embryonal carcinoma stem cells to three substrata: silica-titania (representative of artificial implants); poly-lysine (a commonly used laboratory cell culture substrate); and mucin (the coating of the mucosae). By considering both in-coupling peak width and position, the secretion of microexudate by the cells, the formation of filopodia, and the overall change in their shape (spreading) can be distinguished. This cannot be achieved by the conventional microscopic imaging approach. Moreover, we obtain the kinetics of these processes with excellent time resolution.
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Affiliation(s)
- Amirreza Aref
- Cranfield University, Department of Materials, Bedfordshire MK43 0AL, United Kingdom
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30
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Abstract
The kinetics of adsorption and desorption on a silica-like surface of the large glycoprotein mucin have been measured across a range of temperatures from 25 to 60 degrees C. The area occupied per molecule diminishes with increasing temperature both in the bulk and adsorbed states, implying that the glycoprotein belongs to the "natively open" conformational class. Due to the conformational rearrangement, the specific interaction energy governing desorption greatly increases with temperature, resulting in an impressively regulated temperature-invariant dynamic surface coating.
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Affiliation(s)
- James McColl
- Department of Materials, Cranfield University, Bedfordshire MK43 0AL, UK
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Abstract
Complex solutes may adsorb from solution onto solid surfaces in a concentration-dependent manner. In other words, the adsorption behavior is qualitatively different in different bulk concentration regimes. Here we show that the large glycoprotein mucin not only adsorbs in distinctively different ways according to the bulk concentration but also, strikingly, that the law of desorption, established with the help of high-resolution molecular microscopy, depends on the bulk concentration during adsorption. Making use of supporting bulk rheology data delineating the entangled regime and atomic force microscopy images of the adsorbed layers corroborating the existence of a bilayer structure formed at higher bulk concentrations, a tentative molecular mechanism for the observations is proposed.
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Affiliation(s)
- James McColl
- Department of Materials, Cranfield University, U.K
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Abstract
OBJECTIVES To describe prospectively the evolution of liver abnormalities in cystic fibrosis (CF), and to assess their impact on nutritional status. STUDY DESIGN 124 children (61 boys) with CF (median age, 5.4 years; range, 0.1-13.9) were followed longitudinally for a median of four years. Annual clinical examination, biochemistry, and ultrasound assessment were performed. Chrispin-Norman score, anthropometry, and bacterial colonisation of airway secretions were measured at each assessment. RESULTS At initial assessment, 45% of the patients had no liver abnormalities, 42% had biochemical abnormality, 35% ultrasound abnormality, and 6% had clinical abnormality of the liver. In this cross sectional analysis, abnormal biochemistry was present in 40% of children with ultrasound or clinical abnormalities, but when longitudinal follow up data were analysed, abnormal biochemistry preceded or coincided with abnormal ultrasound or clinical hepatosplenomegaly in three quarters of 53 children developing new abnormalities. Eighty four of 124 children (68%) showed ultrasound or clinical evidence of liver abnormality at some point during the four years of follow up. No association was found between liver disease and nutritional status. CONCLUSIONS Hepatic abnormality was common in this group of children with CF, was often predicted by intermittent biochemical abnormalities, and was not associated with deterioration in nutritional status.
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Affiliation(s)
- S C Ling
- Department of Child Health, University of Glasgow, Yorkhill NHS Trust, Glasgow G3 8SJ, UK.
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Millett DT, Cattanach D, McFadzean R, Pattison J, McColl J. Laboratory evaluation of a compomer and a resin-modified glass ionomer cement for orthodontic bonding. Angle Orthod 1999; 69:58-63; discussion 64. [PMID: 10022186 DOI: 10.1043/0003-3219(1999)069<0058:leoaca>2.3.co;2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The mean shear debonding force of stainless steel orthodontic brackets with microetched bases bonded with either a compomer or a resin-modified glass ionomer cement was assessed. In addition, the amount of cement remaining on the enamel surface following bracket removal was evaluated. Finally, survival time of orthodontic brackets bonded with these materials was assessed following simulated mechanical stress in a ball mill. Debonding force and survival time data were compared with those obtained for brackets bonded with a chemically cured resin adhesive, a light-cured resin adhesive, and a conventional glass ionomer cement. There were no significant differences in mean shear debonding force of brackets bonded with the compomer, resin-modified glass ionomer, chemically cured resin adhesive, or the light-cured resin adhesive. Brackets bonded with a conventional glass ionomer cement had a significantly lower mean shear debonding force than that recorded for the other materials. The Adhesive Remnant Index (ARI) mode score indicated that significantly less cement remained on the enamel following debonding of brackets cemented with resin-modified or conventional glass ionomers compared with other adhesives. The median survival time for brackets cemented with the compomer, resin-modified glass ionomer, chemically cured resin, or light-cured resin were significantly longer than for brackets cemented with conventional glass ionomer. The compomer and the resin-modified glass ionomer adhesive appear to offer viable alternatives to the more commonly used resin adhesives for bracket bonding.
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Affiliation(s)
- D T Millett
- Orthodontic Unit, Glasgow Dental Hospital and School, UK
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Abstract
This laboratory study compared the mean tensile bond strength, mode of band failure, and survival time of orthodontic bands cemented with dual-cured cement or conventional glass ionomer cement. Survival time was assessed following application of mechanical stress in a ball mill. Mean tensile bond strength was significantly higher for bands cemented with the dual-cured cement (p < 0.01), and mean survival time was significantly greater. Bands cemented with glass ionomer failed mainly at the cement/band interface. The results suggest that dual-cured cement is superior to glass ionomer for band cementation.
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Abstract
This nonrandomised retrospective case-comparison survey was based on the hypothesis that craniofacial morphometric features can be used to identify individuals at greater risk for having children with a cleft. The theory of aetiological heterogeneity suggests there may be differences according to gender and cleft type. From a completely ascertained sample of 286 children with cleft lip and/or palate born in the West of Scotland between 1 January 1980 and 31 December 1984, a sample of 83 parents of the children with non-syndromic clefts volunteered for lateral cephalometric examination. A comparison group was derived from the archives of Glasgow Dental Hospital. Multivariate statistical analyses were applied to identify which parental craniofacial parameters, if any, determine predisposition to orofacial clefting. Compared to the male comparison group, the fathers of children with CL(P) were shown to have reduced mandibular and symphyseal areas (P < 0.001), reduced maxillary area (P < 0.01) and a shorter palatal length (P < 0.01). The cranial base angle was more acute (P < 0.01) and the cross-sectional area of the cranium on lateral skull radiographs was significantly smaller (P < 0.001). However, the occipital subtenuce was larger in the fathers (P < 0.05). The craniofacial morphology in the mothers of children with CL(P) was characterized by a longer mandible (P = 0.011), an increase in the anterior facial height (P < 0.05) and greater facial length (P < 0.01). Anterior cranial base and the clivus length were also larger in the mothers (P < 0.05). The cranial parameters showed a similar trend to the paternal group with a reduced cranial area (P < 0.01) and an increase in the occipital subtenuce length (P < 0.001). Different cephalometric parameters distinguish fathers from a male comparison group and mothers from their female counterparts. An awareness of these parameters might be of value in the prediction of liability to clefting and may prove to be important in the quest for clues to the pathogenesis of both CP and CL(P).
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Affiliation(s)
- P A Mossey
- Department of Dental Health University of Dundee, UK
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Mossey PA, Arngrimsson R, McColl J, Vintiner GM, Connor JM. Prediction of liability to orofacial clefting using genetic and craniofacial data from parents. J Med Genet 1998; 35:371-8. [PMID: 9610799 PMCID: PMC1051310 DOI: 10.1136/jmg.35.5.371] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Cleft lip with or without cleft palate (CL(P)) and isolated cleft palate (CP) are separate clinical entities and for both polygenic multifactorial aetiology has been proposed. Parents of children with orofacial clefting have been shown to have distinctive differences in their facial shape when compared to matched controls. OBJECTIVE To test the hypothesis that genetic and morphometric factors predispose to orofacial clefting and that these markers differ for CL(P) and CP. Methods-Polymorphisms at the transforming growth factor alpha (TGFalpha) locus in 83 parents of children with nonsyndromic orofacial clefts were analysed, and their craniofacial morphology was assessed using lateral cephalometry. RESULTS Parents of children with CL(P) and CP showed an increased frequency of the TGFalpha/TaqI C2 allele (RR=4.10, p=0.009) relative to the comparison group. Also the TGFalpha/BamHI A1 allele was more prevalent in the CP parents. MULTIVARIATE STATISTICAL ANALYSIS: Using stepwise logistic regression analysis the TGFalpha/TaqI C2 polymorphism provides the best model for liability to orofacial clefting. To determine the type of clefting a model involving interaction between the parental TGFalpha/BamHI and TGFalpha/RsaI genotypes showed the best fit. Using genotype only to predict the clefting defect in the children according to parental genotype, 68.3% could be correctly classified. By adding information on craniofacial measurements in the parents, 76% of CP and 94% of CL(P) parents could be correctly classified. CONCLUSIONS This study provides a model for prediction of liability to orofacial clefting. These findings suggest that different molecular aberrations at the TGFalpha locus may modify the risk for CP and CL(P).
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Affiliation(s)
- P A Mossey
- Department of Dental Health, University of Dundee Dental School, UK
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Gratton JA, Sauter A, Rudin M, Lees KR, McColl J, Reid JL, Dominiczak AF, Macrae IM. Susceptibility to cerebral infarction in the stroke-prone spontaneously hypertensive rat is inherited as a dominant trait. Stroke 1998; 29:690-4. [PMID: 9506614 DOI: 10.1161/01.str.29.3.690] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND PURPOSE Susceptibility to cerebral infarction was compared in stroke-prone spontaneously hypertensive (SHRSP), normotensive Wistar-Kyoto (WKY) rats, and F1 hybrids derived from a SHRSP/WKY cross. METHODS The proximal left middle cerebral artery (MCA) was occluded under anesthesia and infarct volume assessed 24 hours later by magnetic resonance imaging and confirmed 5 days later by quantitative histopathology. Total hemispheric infarct volume was expressed as a percentage of the total brain volume. RESULTS Infarct volumes measured by MRI in adult SHRSP (19.5 +/- 2.0%) and F1 hybrid rats (19.4 +/- 1.9%) were significantly greater than in WKY (11.1 +/- 2.4; CI [6.07, 10.76]) and (5.93, 10.52), respectively, P<.001). Sensitivity to an ischemic insult was unrelated to blood pressure: although systolic blood pressures differed between young versus adult male SHRSP and between female versus male SHRSP and F1 hybrids, infarct volumes were equal. A close correlation was found between infarct volumes measured by MRI and histology (r=.92, P<.0001). CONCLUSIONS Outcome to MCA occlusion (MCAO) measured with MRI provides a reproducible and nonterminal quantitative phenotypic marker of stroke susceptibility in the SHRSP. This is the first study to employ MCAO with MRI to quantify stroke susceptibility in F1 hybrid rats and indicates a dominant mode of inheritance for this phenotype.
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Affiliation(s)
- J A Gratton
- Wellcome Surgical Institute, University of Glasgow, Scotland, UK
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Madge P, McColl J, Paton J. Impact of a nurse-led home management training programme in children admitted to hospital with acute asthma: a randomised controlled study. Thorax 1997; 52:223-8. [PMID: 9093336 PMCID: PMC1758505 DOI: 10.1136/thx.52.3.223] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Re-admissions to hospital in childhood asthma are common with studies reporting that 25% or more of children will be re-admitted within a year. There is a need for strategies to reduce re-admissions. METHODS A prospective randomised control study of an asthma home management training programme was performed in children aged two years or over admitted with acute asthma. Two hundred and one children were randomised at admission to either an intervention group (n = 96) which received the teaching programme or a control group (n = 105). A nurse-led teaching programme used the current attack as a model for the management of future attacks and included discussion, written information, subsequent follow up and telephone advice aimed at developing and reinforcing individualised asthma management plans. Parents were also provided with a course of oral steroids and guidance on when to start them. RESULTS The groups were similar in degree of social deprivation, length of stay, number of previous admissions, acute asthma treatment, and asthma treatment at discharge. Subsequent re-admissions were significantly reduced in the intervention group from 25% to 8% in individual follow up periods that ranged from two to 14 months (chi 2 = 9.63; p = 0.002). This reduction was not accompanied by any increase in subsequent emergency room attendances nor, in the short term, by any increase in urgent community asthma treatment. The intervention group also showed significant reductions in day and night morbidity 3-4 weeks after admission to hospital. CONCLUSIONS A nurse-led asthma home management training programme administered during a hospital admission can significantly reduce subsequent admissions to hospital for asthma. Acute hospitalisation may be a particularly effective time to deliver home management training.
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Affiliation(s)
- P Madge
- Department of Child Health, Royal Hospital for Sick Children, Yorkhill NHS Trust, Glasgow, UK
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Abstract
Fetal scalp blood lactate was measured during labour by a simple, rapid method and its value as an indicator of fetal intrauterine hypoxia was assessed and compared with that of pH measurement. The normal ranges of lactate concentration and of pH values were calculated. Significantly higher concentrations of lactate and lower pH values were found in samples of scalp blood taken close to delivery from babies with Apgar scores of less than or equal to 6 at 1 min compared with those from healthy babies with Apgar scores of greater than or equal to 7 at 1 min. A similarly significant difference was observed between the cord blood lactate and pH values of these two groups of babies. Ominous fetal heart rate patterns were associated with higher lactate concentrations and lower pH values in fetal scalp blood than were normal fetal heart rate patterns. The measurement of fetal scalp blood lactate or pH, or continuous electronic fetal heart rate monitoring were equally good at predicting the condition of the infant at birth.
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