1
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Montague SJ, Price J, Pennycott K, Pavey NJ, Martin EM, Thirlwell I, Kemble S, Monteiro C, Redmond-Motteram L, Lawson N, Reynolds K, Fratter C, Bignell P, Groenheide A, Huskens D, de Laat B, Pike JA, Poulter NS, Thomas SG, Lowe GC, Lancashire J, Harrison P, Morgan NV. Comprehensive functional characterization of a novel ANO6 variant in a new patient with Scott syndrome. J Thromb Haemost 2024:S1538-7836(24)00127-2. [PMID: 38492852 DOI: 10.1016/j.jtha.2024.02.021] [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] [Received: 10/11/2023] [Revised: 02/09/2024] [Accepted: 02/29/2024] [Indexed: 03/18/2024]
Abstract
BACKGROUND Scott syndrome is a mild platelet-type bleeding disorder, first described in 1979, with only 3 unrelated families identified through defective phosphatidylserine (PS) exposure and confirmed by sequencing. The syndrome is distinguished by impaired surface exposure of procoagulant PS on platelets after stimulation. To date, platelet function and thrombin generation in this condition have not been extensively characterized. OBJECTIVES Genetic and functional studies were undertaken in a consanguineous family with a history of excessive bleeding of unknown cause. METHODS A targeted gene panel of known bleeding and platelet genes was used to identify possible genetic variants. Platelet phenotyping, flow adhesion, flow cytometry, whole blood and platelet-rich plasma thrombin generation, and specialized extracellular vesicle measurements were performed. RESULTS We detected a novel homozygous frameshift variant, c.1943del (p.Arg648Hisfs∗23), in ANO6 encoding Anoctamin 6, in a patient with a bleeding history but interestingly with normal ANO6 expression. Phenotyping of the patient's platelets confirmed the absence of PS expression and procoagulant activity but also revealed other defects including reduced platelet δ granules, reduced ristocetin-mediated aggregation and secretion, and reduced P-selectin expression after stimulation. PS was absent on spread platelets, and thrombi formed over collagen at 1500/s. Reduced thrombin generation was observed in platelet-rich plasma and confirmed in whole blood using a new thrombin generation assay. CONCLUSION We present a comprehensive report of a patient with Scott syndrome with a novel frameshift variant in AN06, which is associated with no platelet PS exposure and markedly reduced thrombin generation in whole blood, explaining the significant bleeding phenotype observed.
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Affiliation(s)
- Samantha J Montague
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Joshua Price
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Katherine Pennycott
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Natasha J Pavey
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Eleyna M Martin
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Isaac Thirlwell
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Samuel Kemble
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Catarina Monteiro
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Lily Redmond-Motteram
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Natalie Lawson
- Haemophilia Unit, Birmingham Children's Hospital, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, United Kingdom
| | - Katherine Reynolds
- Haemophilia Unit, Birmingham Children's Hospital, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, United Kingdom
| | - Carl Fratter
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Patricia Bignell
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | | | - Dana Huskens
- Synapse Research Institute, Maastricht, the Netherlands
| | - Bas de Laat
- Synapse Research Institute, Maastricht, the Netherlands
| | - Jeremy A Pike
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, the Midlands, United Kingdom
| | - Natalie S Poulter
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, the Midlands, United Kingdom
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, the Midlands, United Kingdom
| | - Gillian C Lowe
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom; Comprehensive Care Haemophilia Centre, University Hospital Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Jonathan Lancashire
- Haemophilia Unit, Birmingham Children's Hospital, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, United Kingdom
| | - Paul Harrison
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.
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2
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Brown HC, Beck S, Navarro S, Di Y, Soriano Jerez EM, Kaczmarzyk J, Thomas SG, Mirakaj V, Watson SP, Nieswandt B, Stegner D. Antibody-mediated depletion of human CLEC-2 in a novel humanized mouse model. Blood Adv 2023; 7:997-1000. [PMID: 36044387 PMCID: PMC10027499 DOI: 10.1182/bloodadvances.2021006463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 10/26/2021] [Revised: 08/23/2022] [Accepted: 08/23/2022] [Indexed: 03/09/2023] Open
Affiliation(s)
- Helena C Brown
- Institute of Experimental Biomedicine I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Sarah Beck
- Institute of Experimental Biomedicine I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
| | - Stefano Navarro
- Institute of Experimental Biomedicine I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Ying Di
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Eva M Soriano Jerez
- Institute of Experimental Biomedicine I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom
| | - Jana Kaczmarzyk
- Institute of Experimental Biomedicine I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Valbona Mirakaj
- Division of Molecular Intensive Care Medicine, Department of Anesthesiology and Intensive Care Medicine, Eberhard - Karls University of Tübingen, Tübingen, Germany
| | - Steve P Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Bernhard Nieswandt
- Institute of Experimental Biomedicine I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
| | - David Stegner
- Institute of Experimental Biomedicine I, University Hospital and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
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3
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Faulkner EL, Pike JA, Densham RM, Garlick E, Thomas SG, Neely RK, Morris JR. Imaging nanoscale nuclear structures with expansion microscopy. J Cell Sci 2022; 135:276027. [PMID: 35748225 PMCID: PMC9450888 DOI: 10.1242/jcs.259009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 06/21/2022] [Indexed: 11/20/2022] Open
Abstract
Commonly applied super-resolution light microscopies have provided insight into subcellular processes at the nanoscale. However, imaging depth, speed, throughput and cost remain significant challenges, limiting the numbers of three-dimensional (3D) nanoscale processes that can be investigated and the number of laboratories able to undertake such analysis. Expansion microscopy (ExM) solves many of these limitations, but its application to imaging nuclear processes has been constrained by concerns of unequal nuclear expansion. Here, we demonstrate the conditions for isotropic expansion of the nucleus at a resolution equal to or better than 120–130 nm (pre-expansion). Using the DNA damage response proteins BRCA1, 53BP1 (also known as TP53BP1) and RAD51 as exemplars, we quantitatively describe the 3D nanoscale organisation of over 50,000 DNA damage response structures. We demonstrate the ability to assess chromatin-regulated events and show the simultaneous assessment of four elements. This study thus demonstrates how ExM can contribute to the investigation of nanoscale nuclear processes. Summary: Expansion microscopy provides quantitative insight into the impact of chromatin modifiers on spatiotemporal organisation of the DNA repair proteins BRCA1, 53BP1 and RAD51 at a resolution of 65–70 nm.
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Affiliation(s)
- Emma L Faulkner
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Jeremy A Pike
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.,COMPARE, University of Birmingham and University of Nottingham, Midlands, UK
| | - Ruth M Densham
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, University of Birmingham, B15 2TT, UK
| | - Evelyn Garlick
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.,COMPARE, University of Birmingham and University of Nottingham, Midlands, UK
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.,COMPARE, University of Birmingham and University of Nottingham, Midlands, UK
| | - Robert K Neely
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Joanna R Morris
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, University of Birmingham, B15 2TT, UK
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4
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Kemble S, Dalby A, Lowe GC, Nicolson PLR, Watson SP, Senis Y, Thomas SG, Harrison P. Analysis of preplatelets and their barbell platelet derivatives by imaging flow cytometry. Blood Adv 2022; 6:2932-2946. [PMID: 35042240 PMCID: PMC9092408 DOI: 10.1182/bloodadvances.2021006073] [Citation(s) in RCA: 9] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/21/2021] [Indexed: 11/20/2022] Open
Abstract
Circulating large "preplatelets" undergo fission via barbell platelet intermediates into two smaller, mature platelets. In this study, we determine whether preplatelets and/or barbells are equivalent to reticulated/immature platelets by using ImageStream flow cytometry and super-resolution microscopy. Immature platelets, preplatelets, and barbells were quantified in healthy and thrombocytopenic mice, healthy human volunteers, and patients with immune thrombocytopenia or undergoing chemotherapy. Preplatelets and barbells were 1.9% ± 0.18%/1.7% ± 0.48% (n = 6) and 3.3% ± 1.6%/0.5% ± 0.27% (n = 12) of total platelet counts in murine and human whole blood, respectively. Both preplatelets and barbells exhibited high expression of major histocompatibility complex class I with high thiazole orange and Mitotracker fluorescence. Tracking dye experiments confirmed that preplatelets transform into barbells and undergo fission ex vivo to increase platelet counts, with dependence on the cytoskeleton and normal mitochondrial respiration. Samples from antibody-induced thrombocytopenia in mice and patients with immune thrombocytopenia had increased levels of both preplatelets and barbells correlating with immature platelet levels. Furthermore, barbells were absent after chemotherapy in patients. In mice, in vivo biotinylation confirmed that barbells, but not all large platelets, were immature. This study demonstrates that a subpopulation of large platelets are immature preplatelets that can transform into barbells and undergo fission during maturation.
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Affiliation(s)
| | - Amanda Dalby
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, United Kingdom
| | - Gillian C. Lowe
- West Midlands Haemophilia Comprehensive Care Centre, University Hospitals Birmingham Foundation Trust, Birmingham, United Kingdom; and
| | - Phillip L. R. Nicolson
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
- West Midlands Haemophilia Comprehensive Care Centre, University Hospitals Birmingham Foundation Trust, Birmingham, United Kingdom; and
| | - Steve P. Watson
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, United Kingdom
| | - Yotis Senis
- Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Steven G. Thomas
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, United Kingdom
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5
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Garlick E, Thomas SG, Owen DM. Super-Resolution Imaging Approaches for Quantifying F-Actin in Immune Cells. Front Cell Dev Biol 2021; 9:676066. [PMID: 34490240 PMCID: PMC8416680 DOI: 10.3389/fcell.2021.676066] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/20/2021] [Indexed: 11/21/2022] Open
Abstract
Immune cells comprise a diverse set of cells that undergo a complex array of biological processes that must be tightly regulated. A key component of cellular machinery that achieves this is the cytoskeleton. Therefore, imaging and quantitatively describing the architecture and dynamics of the cytoskeleton is an important research goal. Optical microscopy is well suited to this task. Here, we review the latest in the state-of-the-art methodology for labeling the cytoskeleton, fluorescence microscopy hardware suitable for such imaging and quantitative statistical analysis software applicable to describing cytoskeletal structures. We also highlight ongoing challenges and areas for future development.
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Affiliation(s)
- Evelyn Garlick
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, United Kingdom
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, United Kingdom
| | - Dylan M Owen
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, United Kingdom.,Institute for Immunology and Immunotherapy, College of Medical and Dental Science and School of Mathematics, College of Engineering and Physical Science, University of Birmingham, Birmingham, United Kingdom
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6
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Rupf R, Tsai MC, Thomas SG, Klimstra M. Original article: Validity of measuring wheelchair kinematics using one inertial measurement unit during commonly used testing protocols in elite wheelchair court sports. J Biomech 2021; 127:110654. [PMID: 34385049 DOI: 10.1016/j.jbiomech.2021.110654] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 03/30/2021] [Revised: 07/15/2021] [Accepted: 07/25/2021] [Indexed: 11/20/2022]
Abstract
Wheelchair court sports can measure both continuous and discrete wheelchair kinematics using Inertial Measurement Units (IMU) during testing and games. A method involving three IMU (3IMU) shows good validity with motion capture systems, but the hardware cost and the need for multiple sensors may make it a barrier for implementation in a sport context. A method using only one wheel mounted IMU (1IMU) has been developed that may reduce this cost, but further validation is required. This study assessed the validity of 1IMU compared to 3IMU, across a variety of continuous and discrete measurements during common on-court testing protocols, using national team athletes. Subjects recruited from national Wheelchair Basketball and Wheelchair Rugby programs performed a series of sprint, agility, and pivot testing protocols. Continuous wheel speed, frame rotation, and wheelchair speed data as well as a number of important discrete metrics including peak linear and rotational speeds, were compared between 3IMU and 1IMU. Low error (RMSE < 0.15 m s-1) and high linearity (R2 > 0.99) were seen in continuous measurements for wheel speed. Similar observations were made for frame rotational speed (RMSE < 11° s-1 and R2 < 0.97) during continuous measurements. Good to excellent intraclass correlations (ICC) were observed for peak linear speeds (ICC > 0.86) and frame rotational speeds (ICC > 0.94). Overall, 1IMU offers a lower cost solution that provides valid information for pertinent outcomes in wheelchair sports to use in the field.
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Affiliation(s)
- R Rupf
- University of Toronto, Faculty of Kinesiology and Physical Education, Graduate Department of Kinesiology, Canada.
| | - M C Tsai
- Canadian Sport Institute Pacific, Canada
| | - S G Thomas
- University of Toronto, Faculty of Kinesiology and Physical Education, Canada
| | - M Klimstra
- Canadian Sport Institute Pacific, Canada; University of Victoria, School of Exercise Science, Physical and Health Education, Canadian Sport Institute Pacific, Canada
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7
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Bourne JH, Beristain-Covarrubias N, Zuidscherwoude M, Campos J, Di Y, Garlick E, Colicchia M, Terry LV, Thomas SG, Brill A, Bayry J, Watson SP, Rayes J. CLEC-2 Prevents Accumulation and Retention of Inflammatory Macrophages During Murine Peritonitis. Front Immunol 2021; 12:693974. [PMID: 34163489 PMCID: PMC8215360 DOI: 10.3389/fimmu.2021.693974] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 04/12/2021] [Accepted: 05/20/2021] [Indexed: 11/29/2022] Open
Abstract
Platelets play a key role in the development, progression and resolution of the inflammatory response during sterile inflammation and infection, although the mechanism is not well understood. Here we show that platelet CLEC-2 reduces tissue inflammation by regulating inflammatory macrophage activation and trafficking from the inflamed tissues. The immune regulatory function of CLEC-2 depends on the expression of its ligand, podoplanin, upregulated on inflammatory macrophages and is independent of platelet activation and secretion. Mechanistically, platelet CLEC-2 and also recombinant CLEC-2-Fc accelerates actin rearrangement and macrophage migration by increasing the expression of podoplanin and CD44, and their interaction with the ERM proteins. During ongoing inflammation, induced by lipopolysaccharide, treatment with rCLEC-2-Fc induces the rapid emigration of peritoneal inflammatory macrophages to mesenteric lymph nodes, thus reducing the accumulation of inflammatory macrophages in the inflamed peritoneum. This is associated with a significant decrease in pro-inflammatory cytokine, TNF-α and an increase in levels of immunosuppressive, IL-10 in the peritoneum. Increased podoplanin expression and actin remodelling favour macrophage migration towards CCL21, a soluble ligand for podoplanin and chemoattractant secreted by lymph node lymphatic endothelial cells. Macrophage efflux to draining lymph nodes induces T cell priming. In conclusion, we show that platelet CLEC-2 reduces the inflammatory phenotype of macrophages and their accumulation, leading to diminished tissue inflammation. These immunomodulatory functions of CLEC-2 are a novel strategy to reduce tissue inflammation and could be therapeutically exploited through rCLEC-2-Fc, to limit the progression to chronic inflammation.
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Affiliation(s)
- Joshua H. Bourne
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Nonantzin Beristain-Covarrubias
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Malou Zuidscherwoude
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Joana Campos
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ying Di
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Evelyn Garlick
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Martina Colicchia
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Lauren V. Terry
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Steven G. Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Alexander Brill
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Pathophysiology, Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Jagadeesh Bayry
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Equipe - Immunopathologie et Immunointervention Thérapeutique, Sorbonne Université, Université de Paris, Paris, France
- Biological Sciences and Engineering, Indian Institute of Technology Palakkad, Kerala, India
| | - Steve P. Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, United Kingdom
| | - Julie Rayes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, The Midlands, United Kingdom
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8
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Khan AO, Slater A, Maclachlan A, Nicolson PLR, Pike JA, Reyat JS, Yule J, Stapley R, Rayes J, Thomas SG, Morgan NV. Post-translational polymodification of β1-tubulin regulates motor protein localisation in platelet production and function. Haematologica 2020; 107:243-259. [PMID: 33327716 PMCID: PMC8719104 DOI: 10.3324/haematol.2020.270793] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 08/28/2020] [Indexed: 11/17/2022] Open
Abstract
In specialized cells, the expression of specific tubulin isoforms and their subsequent post-translational modifications drive and coordinate unique morphologies and behaviors. The mechanisms by which b1-tubulin, the platelet and megakaryocyte (MK) lineage restricted tubulin isoform, drives platelet production and function remains poorly understood. We investigated the roles of two key post-translational tubulin polymodifications (polyglutamylation and polyglycylation) on these processes using a cohort of thrombocytopenic patients, human induced pluripotent stem cell derived MK, and healthy human donor platelets. We find distinct patterns of polymodification in MK and platelets, mediated by the antagonistic activities of the cell specific expression of tubulin tyrosine ligase like enzymes and cytosolic carboxypeptidase enzymes. The resulting microtubule patterning spatially regulates motor proteins to drive proplatelet formation in megakaryocytes, and the cytoskeletal reorganization required for thrombus formation. This work is the first to show a reversible system of polymodification by which different cell specific functions are achieved.
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Affiliation(s)
- Abdullah O Khan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT.
| | - Alexandre Slater
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Annabel Maclachlan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Phillip L R Nicolson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Jeremy A Pike
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT; Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands
| | - Jasmeet S Reyat
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Jack Yule
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands
| | - Rachel Stapley
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Julie Rayes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT; Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands
| | - Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT.
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9
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Senter DM, Douglas DR, Strickland WC, Thomas SG, Talkington AM, Miller LA, Battista NA. A semi-automated finite difference mesh creation method for use with immersed boundary software IB2d and IBAMR. Bioinspir Biomim 2020; 16:10.1088/1748-3190/ababb0. [PMID: 32746437 PMCID: PMC7970534 DOI: 10.1088/1748-3190/ababb0] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
Numerous fluid-structure interaction problems in biology have been investigated using the immersed boundary method. The advantage of this method is that complex geometries, e.g., internal or external morphology, can easily be handled without the need to generate matching grids for both the fluid and the structure. Consequently, the difficulty of modeling the structure lies often in discretizing the boundary of the complex geometry (morphology). Both commercial and open source mesh generators for finite element methods have long been established; however, the traditional immersed boundary method is based on a finite difference discretization of the structure. Here we present a software library for obtaining finite difference discretizations of boundaries for direct use in the 2D immersed boundary method. This library provides tools for extracting such boundaries as discrete mesh points from digital images. We give several examples of how the method can be applied that include passing flow through the veins of insect wings, within lymphatic capillaries, and around starfish using open-source immersed boundary software.
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Affiliation(s)
- D Michael Senter
- Dept. of Mathematics, CB 3250, University of North Carolina, Chapel Hill, NC, 27599, United States of America
- Bioinformatics. and Comp. Biology, CB 7264, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
| | - Dylan R Douglas
- Dept. of Mathematics, CB 3250, University of North Carolina, Chapel Hill, NC, 27599, United States of America
- Department of Mathematics, University of Arizona, 617 N. Santa Rita Ave. P.O. Box 210089 Tucson, AZ 85721-0089, United States of America
| | - W Christopher Strickland
- Dept. of Mathematics, CB 3250, University of North Carolina, Chapel Hill, NC, 27599, United States of America
- Dept. of Mathematics, 1403 Circle Drive, University of Tennessee at Knoxville, Knoxville, TN 37919, United States of America
| | - Steven G Thomas
- Dept. of Mathematics, CB 3250, University of North Carolina, Chapel Hill, NC, 27599, United States of America
| | - Anne M Talkington
- Dept. of Mathematics, CB 3250, University of North Carolina, Chapel Hill, NC, 27599, United States of America
- Bioinformatics. and Comp. Biology, CB 7264, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
| | - Laura A Miller
- Dept. of Mathematics, CB 3250, University of North Carolina, Chapel Hill, NC, 27599, United States of America
- Bioinformatics. and Comp. Biology, CB 7264, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States of America
- Department of Mathematics, University of Arizona, 617 N. Santa Rita Ave. P.O. Box 210089 Tucson, AZ 85721-0089, United States of America
| | - Nicholas A Battista
- Dept. of Mathematics and Statistics, The College of New Jersey, 2000 Pennington Rd., Ewing, NJ 08628, United States of America
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10
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Zuidscherwoude M, Haining EJ, Simms VA, Watson S, Grygielska B, Hardy AT, Bacon A, Watson SP, Thomas SG. Loss of mDia1 and Fhod1 impacts platelet formation but not platelet function. Platelets 2020; 32:1051-1062. [PMID: 32981398 PMCID: PMC8635707 DOI: 10.1080/09537104.2020.1822522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 11/01/2022]
Abstract
An organized and dynamic cytoskeleton is required for platelet formation and function. Formins are a large family of actin regulatory proteins which are also able to regulate microtubule dynamics. There are four formin family members expressed in human and mouse megakaryocytes and platelets. We have previously shown that the actin polymerization activity of formin proteins is required for cytoskeletal dynamics and platelet spreading using a small molecule inhibitor. In the current study, we analyze transgenic mouse models deficient in two of these proteins, mDia1 and Fhod1, along with a model lacking both proteins. We demonstrate that double knockout mice display macrothrombocytopenia which is due to aberrant megakaryocyte function and a small decrease in platelet lifespan. Platelet function is unaffected by the loss of these proteins. This data indicates a critical role for formins in platelet and megakaryocyte function.
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Affiliation(s)
- Malou Zuidscherwoude
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Elizabeth J. Haining
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Victoria A. Simms
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Stephanie Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Beata Grygielska
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Alex T. Hardy
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Andrea Bacon
- Genome Editing Facility, Technology Hub, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Stephen P. Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Steven G. Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
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11
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Pike JA, Khan AO, Pallini C, Thomas SG, Mund M, Ries J, Poulter NS, Styles IB. Topological data analysis quantifies biological nano-structure from single molecule localization microscopy. Bioinformatics 2020; 36:1614-1621. [PMID: 31626286 PMCID: PMC7162425 DOI: 10.1093/bioinformatics/btz788] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [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: 12/12/2018] [Revised: 09/03/2019] [Accepted: 10/17/2019] [Indexed: 01/23/2023] Open
Abstract
Motivation Localization microscopy data is represented by a set of spatial coordinates, each corresponding to a single detection, that form a point cloud. This can be analyzed either by rendering an image from these coordinates, or by analyzing the point cloud directly. Analysis of this type has focused on clustering detections into distinct groups which produces measurements such as cluster area, but has limited capacity to quantify complex molecular organization and nano-structure. Results We present a segmentation protocol which, through the application of persistence-based clustering, is capable of probing densely packed structures which vary in scale. An increase in segmentation performance over state-of-the-art methods is demonstrated. Moreover we employ persistent homology to move beyond clustering, and quantify the topological structure within data. This provides new information about the preserved shapes formed by molecular architecture. Our methods are flexible and we demonstrate this by applying them to receptor clustering in platelets, nuclear pore components, endocytic proteins and microtubule networks. Both 2D and 3D implementations are provided within RSMLM, an R package for pointillist-based analysis and batch processing of localization microscopy data. Availability and implementation RSMLM has been released under the GNU General Public License v3.0 and is available at https://github.com/JeremyPike/RSMLM. Tutorials for this library implemented as Binder ready Jupyter notebooks are available at https://github.com/JeremyPike/RSMLM-tutorials. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Jeremy A Pike
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Abdullah O Khan
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Chiara Pallini
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Steven G Thomas
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Markus Mund
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg 69117, Germany.,Department of Biochemistry, University of Geneva, 1211 Geneva 4, Switzerland
| | - Jonas Ries
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg 69117, Germany
| | - Natalie S Poulter
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Iain B Styles
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,School of Computer Science, University of Birmingham, Birmingham B15 2TT, UK
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12
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Affiliation(s)
- Steven G Thomas
- Institute of Cardiovascular Science, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham , Midlands, UK
| | - Natalie S Poulter
- Institute of Cardiovascular Science, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham , Midlands, UK
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13
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Faulkner EL, Thomas SG, Neely RK. An introduction to the methodology of expansion microscopy. Int J Biochem Cell Biol 2020; 124:105764. [PMID: 32407880 DOI: 10.1016/j.biocel.2020.105764] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 03/04/2020] [Revised: 04/30/2020] [Accepted: 05/03/2020] [Indexed: 01/21/2023]
Abstract
Expansion microscopy is a novel, fluorescence imaging technique, which allows three-dimensional nanoscale imaging of specimens on a conventional fluorescence microscope. This is achieved through an innovative sample treatment, which culminates in approximately 4.5-fold expansion of specimens in each dimension. This allows 70 nm lateral and 200 nm axial resolution. To further develop application of the technique, there has been considerable focus on improving the methodology by i) extending the efficacy of labelling, ii) enabling multi-colour labelling of different biomolecules simultaneously, iii) further improving resolving power through alterations to sample preparation and iv) by combination of expansion microscopy with other well-established super resolution techniques. This review will highlight some of these recent advances and suggest ways that the technique could be developed further in the future.
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Affiliation(s)
- Emma L Faulkner
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Birmingham, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Robert K Neely
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK; School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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14
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Pike JA, Simms VA, Smith CW, Morgan NV, Khan AO, Poulter NS, Styles IB, Thomas SG. An adaptable analysis workflow for characterization of platelet spreading and morphology. Platelets 2020; 32:54-58. [PMID: 32321340 PMCID: PMC8802896 DOI: 10.1080/09537104.2020.1748588] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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] [Indexed: 01/04/2023]
Abstract
The assessment of platelet spreading through light microscopy, and the subsequent quantification of parameters such as surface area and circularity, is a key assay for many platelet biologists. Here we present an analysis workflow which robustly segments individual platelets to facilitate the analysis of large numbers of cells while minimizing user bias. Image segmentation is performed by interactive learning and touching platelets are separated with an efficient semi-automated protocol. We also use machine learning methods to robustly automate the classification of platelets into different subtypes. These adaptable and reproducible workflows are made freely available and are implemented using the open-source software KNIME and ilastik.
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Affiliation(s)
- Jeremy A Pike
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham , Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK
| | - Victoria A Simms
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK
| | - Christopher W Smith
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK
| | - Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK
| | - Abdullah O Khan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK
| | - Natalie S Poulter
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham , Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK
| | - Iain B Styles
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham , Midlands, UK.,School of Computer Science, University of Birmingham , Birmingham, UK
| | - Steven G Thomas
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham , Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham , Birmingham, UK
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15
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Green HLH, Zuidscherwoude M, Alenazy F, Smith CW, Bender M, Thomas SG. SMIFH2 inhibition of platelets demonstrates a critical role for formin proteins in platelet cytoskeletal dynamics. J Thromb Haemost 2020; 18:955-967. [PMID: 31930764 PMCID: PMC7186844 DOI: 10.1111/jth.14735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 06/19/2019] [Accepted: 01/07/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND Reorganization of the actin cytoskeleton is required for proper functioning of platelets following activation in response to vascular damage. Formins are a family of proteins that regulate actin polymerization and cytoskeletal organization via a number of domains including the FH2 domain. However, the role of formins in platelet spreading has not been studied in detail. OBJECTIVES Several formin proteins are expressed in platelets so we used an inhibitor of FH2 domains (SMIFH2) to uncover the role of these proteins in platelet spreading and in maintenance of resting platelet shape. METHODS Washed human and mouse platelets were treated with various concentrations of SMIFH2 and the effects on platelet spreading, platelet size, platelet cytoskeletal dynamics, and organization were analyzed using fluorescence and electron microscopy. RESULTS Pretreatment with SMIFH2 completely blocks platelet spreading in both mouse and human platelets through effects on the organization and dynamics of actin and microtubules. However, platelet aggregation and secretion are unaffected. SMIFH2 also caused a decrease in resting platelet size and disrupted the balance of tubulin post-translational modification. CONCLUSIONS These data therefore demonstrated an important role for formin-mediated actin polymerization in platelet spreading and highlighted the importance of formins in cross-talk between the actin and tubulin cytoskeletons.
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Affiliation(s)
- Hannah L. H. Green
- Institute of Cardiovascular SciencesUniversity of BirminghamBirminghamUK
- Present address:
School of Cardiovascular Medicine & SciencesBHF Centre of Research ExcellenceKing's College LondonLondonUK
| | - Malou Zuidscherwoude
- Institute of Cardiovascular SciencesUniversity of BirminghamBirminghamUK
- Centre of Membrane Proteins and Receptors (COMPARE)University of Birmingham and University of NottinghamMidlandsUK
| | - Fawaz Alenazy
- Institute of Cardiovascular SciencesUniversity of BirminghamBirminghamUK
| | | | - Markus Bender
- Institute of Experimental Biomedicine – Chair IUniversity Hospital and Rudolf Virchow CenterWürzburgGermany
| | - Steven G. Thomas
- Institute of Cardiovascular SciencesUniversity of BirminghamBirminghamUK
- Centre of Membrane Proteins and Receptors (COMPARE)University of Birmingham and University of NottinghamMidlandsUK
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16
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Khan AO, Di Maio A, Guggenheim EJ, Chetwynd AJ, Pencross D, Tang S, Belinga-Desaunay MFA, Thomas SG, Rappoport JZ, Lynch I. Surface Chemistry-Dependent Evolution of the Nanomaterial Corona on TiO 2 Nanomaterials Following Uptake and Sub-Cellular Localization. Nanomaterials (Basel) 2020; 10:nano10030401. [PMID: 32106393 PMCID: PMC7152854 DOI: 10.3390/nano10030401] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/20/2020] [Accepted: 02/20/2020] [Indexed: 12/14/2022]
Abstract
Nanomaterial (NM) surface chemistry has an established and significant effect on interactions at the nano-bio interface, with important toxicological consequences for manufactured NMs, as well as potent effects on the pharmacokinetics and efficacy of nano-therapies. In this work, the effects of different surface modifications (PVP, Dispex AA4040, and Pluronic F127) on the uptake, cellular distribution, and degradation of titanium dioxide NMs (TiO2 NMs, ~10 nm core size) are assessed and correlated with the localization of fluorescently-labeled serum proteins forming their coronas. Imaging approaches with an increasing spatial resolution, including automated high throughput live cell imaging, correlative confocal fluorescence and reflectance microscopy, and dSTORM super-resolution microscopy, are used to explore the cellular fate of these NMs and their associated serum proteins. Uncoated TiO2 NMs demonstrate a rapid loss of corona proteins, while surface coating results in the retention of the corona signal after internalization for at least 24 h (varying with coating composition). Imaging with two-color super-resolution dSTORM revealed that the apparent TiO2 NM single agglomerates observed in diffraction-limited confocal microscopy are actually adjacent smaller agglomerates, and provides novel insights into the spatial arrangement of the initial and exchanged coronas adsorbed at the NM surfaces.
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Affiliation(s)
- Abdullah O. Khan
- Institute of Cardiovascular Science, College of Medical Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (A.O.K.); (D.P.); (S.G.T.)
| | - Alessandro Di Maio
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK;
| | - Emily J. Guggenheim
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (E.J.G.); (A.J.C.); (M.-F.A.B.-D.)
| | - Andrew J. Chetwynd
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (E.J.G.); (A.J.C.); (M.-F.A.B.-D.)
| | - Dan Pencross
- Institute of Cardiovascular Science, College of Medical Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (A.O.K.); (D.P.); (S.G.T.)
| | - Selina Tang
- Promethean Particles Ltd., 1-3 Genesis Park, Midland Way, Nottingham NG7 3EF, UK;
| | - Marie-France A. Belinga-Desaunay
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (E.J.G.); (A.J.C.); (M.-F.A.B.-D.)
| | - Steven G. Thomas
- Institute of Cardiovascular Science, College of Medical Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (A.O.K.); (D.P.); (S.G.T.)
| | - Joshua Z. Rappoport
- Boston College, Higgins 644A, 140 Commonwealth Ave, Chestnut Hill, MA 02467, USA
| | - Iseult Lynch
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (E.J.G.); (A.J.C.); (M.-F.A.B.-D.)
- Correspondence:
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17
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Khan AO, White CW, Pike JA, Yule J, Slater A, Hill SJ, Poulter NS, Thomas SG, Morgan NV. Optimised insert design for improved single-molecule imaging and quantification through CRISPR-Cas9 mediated knock-in. Sci Rep 2019; 9:14219. [PMID: 31578415 PMCID: PMC6775134 DOI: 10.1038/s41598-019-50733-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [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: 04/05/2019] [Accepted: 09/18/2019] [Indexed: 12/29/2022] Open
Abstract
The use of CRISPR-Cas9 genome editing to introduce endogenously expressed tags has the potential to address a number of the classical limitations of single molecule localisation microscopy. In this work we present the first systematic comparison of inserts introduced through CRISPR-knock in, with the aim of optimising this approach for single molecule imaging. We show that more highly monomeric and codon optimised variants of mEos result in improved expression at the TubA1B locus, despite the use of identical guides, homology templates, and selection strategies. We apply this approach to target the G protein-coupled receptor (GPCR) CXCR4 and show a further insert dependent effect on expression and protein function. Finally, we show that compared to over-expressed CXCR4, endogenously labelled samples allow for accurate single molecule quantification on ligand treatment. This suggests that despite the complications evident in CRISPR mediated labelling, the development of CRISPR-PALM has substantial quantitative benefits.
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Affiliation(s)
- Abdullah O Khan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Carl W White
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Jeremy A Pike
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Jack Yule
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Alexandre Slater
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Stephen J Hill
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Natalie S Poulter
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK.
| | - Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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18
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Khan AO, Maclachlan A, Lowe GC, Nicolson PLR, Ghaithi RA, Thomas SG, Watson SP, Pike JA, Morgan NV. High-throughput platelet spreading analysis: a tool for the diagnosis of platelet-based bleeding disorders. Haematologica 2019; 105:e124-e128. [PMID: 31221775 DOI: 10.3324/haematol.2019.225912] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Abdullah O Khan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham
| | - Annabel Maclachlan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham
| | - Gillian C Lowe
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham
| | - Phillip L R Nicolson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham
| | - Rashid Al Ghaithi
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham.,Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Steve P Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham.,Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Jeremy A Pike
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham.,Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham
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19
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Abstract
The platelet and megakaryocyte cytoskeletons are essential for formation and function of these cells. A dynamic, properly organised tubulin and actin cytoskeleton is critical for the development of the megakaryocyte and the extension of proplatelets. Tubulin in particular plays a pivotal role in the extension of these proplatelets and the release of platelets from them. Tubulin is further required for the maintenance of platelet size, and actin is the driving force for shape change, spreading and platelet contraction during platelet activation. Whilst several key proteins which regulate these cytoskeletons have been described in detail, the formin family of proteins has received less attention. Formins are intriguing as, although they were initially believed to simply be a nucleator of actin polymerisation, increasing evidence shows they are important regulators of the crosstalk between the actin and microtubule cytoskeletons. In this review, we will introduce the formin proteins and consider the recent evidence that they play an important role in platelets and megakaryocytes in mediating both the actin and tubulin cytoskeletons.
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Affiliation(s)
- Malou Zuidscherwoude
- a Institute of Cardiovascular Sciences , University of Birmingham , Birmingham , UK.,b Centre of Membrane Proteins and Receptors (COMPARE) , University of Birmingham and University of Nottingham , Midlands , UK
| | - Hannah L H Green
- a Institute of Cardiovascular Sciences , University of Birmingham , Birmingham , UK
| | - Steven G Thomas
- a Institute of Cardiovascular Sciences , University of Birmingham , Birmingham , UK.,b Centre of Membrane Proteins and Receptors (COMPARE) , University of Birmingham and University of Nottingham , Midlands , UK
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20
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Atkinson L, Yusuf MZ, Aburima A, Ahmed Y, Thomas SG, Naseem KM, Calaminus SDJ. Reversal of stress fibre formation by Nitric Oxide mediated RhoA inhibition leads to reduction in the height of preformed thrombi. Sci Rep 2018; 8:3032. [PMID: 29445102 PMCID: PMC5813033 DOI: 10.1038/s41598-018-21167-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [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: 09/25/2017] [Accepted: 01/24/2018] [Indexed: 01/10/2023] Open
Abstract
Evidence has emerged to suggest that thrombi are dynamic structures with distinct areas of differing platelet activation and inhibition. We hypothesised that Nitric oxide (NO), a platelet inhibitor, can modulate the actin cytoskeleton reversing platelet spreading, and therefore reduce the capability of thrombi to withstand a high shear environment. Our data demonstrates that GSNO, DEANONOate, and a PKG-activating cGMP analogue reversed stress fibre formation and increased actin nodule formation in adherent platelets. This effect is sGC dependent and independent of ADP and thromboxanes. Stress fibre formation is a RhoA dependent process and NO induced RhoA inhibition, however, it did not phosphorylate RhoA at ser188 in spread platelets. Interestingly NO and PGI2 synergise to reverse stress fibre formation at physiologically relevant concentrations. Analysis of high shear conditions indicated that platelets activated on fibrinogen, induced stress fibre formation, which was reversed by GSNO treatment. Furthermore, preformed thrombi on collagen post perfused with GSNO had a 30% reduction in thrombus height in comparison to the control. This study demonstrates that NO can reverse key platelet functions after their initial activation and identifies a novel mechanism for controlling excessive thrombosis.
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Affiliation(s)
- L Atkinson
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, HU6 7RX, UK
| | - M Z Yusuf
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, HU6 7RX, UK
| | - A Aburima
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, HU6 7RX, UK
| | - Y Ahmed
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, HU6 7RX, UK
| | - S G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, UK
| | - K M Naseem
- Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, UK
| | - S D J Calaminus
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, HU6 7RX, UK.
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21
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Messaoudi K, Ali A, Ishaq R, Palazzo A, Sliwa D, Bluteau O, Souquère S, Muller D, Diop KM, Rameau P, Lapierre V, Marolleau JP, Matthias P, Godin I, Pierron G, Thomas SG, Watson SP, Droin N, Vainchenker W, Plo I, Raslova H, Debili N. Critical role of the HDAC6-cortactin axis in human megakaryocyte maturation leading to a proplatelet-formation defect. Nat Commun 2017; 8:1786. [PMID: 29176689 PMCID: PMC5702605 DOI: 10.1038/s41467-017-01690-2] [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: 07/20/2016] [Accepted: 10/10/2017] [Indexed: 01/08/2023] Open
Abstract
Thrombocytopenia is a major side effect of a new class of anticancer agents that target histone deacetylase (HDAC). Their mechanism is poorly understood. Here, we show that HDAC6 inhibition and genetic knockdown lead to a strong decrease in human proplatelet formation (PPF). Unexpectedly, HDAC6 inhibition-induced tubulin hyperacetylation has no effect on PPF. The PPF decrease induced by HDAC6 inhibition is related to cortactin (CTTN) hyperacetylation associated with actin disorganization inducing important changes in the distribution of megakaryocyte (MK) organelles. CTTN silencing in human MKs phenocopies HDAC6 inactivation and knockdown leads to a strong PPF defect. This is rescued by forced expression of a deacetylated CTTN mimetic. Unexpectedly, unlike human-derived MKs, HDAC6 and CTTN are shown to be dispensable for mouse PPF in vitro and platelet production in vivo. Our results highlight an unexpected function of HDAC6–CTTN axis as a positive regulator of human but not mouse MK maturation. Histone deacetylase (HDAC) inhibitors, a class of cancer therapeutics, cause thrombocytopenia via an unknown mechanism. Here, the authors show that HDAC6 inhibition impairs proplatelet formation in human megakaryocytes, and show that this is linked to hyperacetylation of the actin-binding protein cortactin.
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Affiliation(s)
- Kahia Messaoudi
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Paris7 Diderot University, 75013, Paris, France
| | - Ashfaq Ali
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Paris7 Diderot University, 75013, Paris, France
| | - Rameez Ishaq
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Paris7 Diderot University, 75013, Paris, France
| | - Alberta Palazzo
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Paris7 Diderot University, 75013, Paris, France
| | - Dominika Sliwa
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Olivier Bluteau
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Sylvie Souquère
- CNRS-UMR-9196, Institut Gustave Roussy, 94805, Villejuif, France
| | - Delphine Muller
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Khadija M Diop
- Genomic Platform, Institut Gustave Roussy, 94805, Villejuif, France
| | - Philippe Rameau
- Gustave Roussy, Integrated Biology Core Facility, 94805, Villejuif, France
| | | | - Jean-Pierre Marolleau
- Clinical Hematology and Cell Therapy Department, Amiens Hospital, UPJV University EA4666, 80054, Amiens, France
| | - Patrick Matthias
- Friedrich Miescher Institute for Biomedical Research, 4002, Basel, Switzerland
| | - Isabelle Godin
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Gérard Pierron
- CNRS-UMR-9196, Institut Gustave Roussy, 94805, Villejuif, France
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK
| | - Stephen P Watson
- Institute of Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK
| | - Nathalie Droin
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Genomic Platform, Institut Gustave Roussy, 94805, Villejuif, France
| | - William Vainchenker
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Isabelle Plo
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Hana Raslova
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Najet Debili
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France. .,Paris-Saclay University, UMR 1170, 94805, Villejuif, France. .,Gustave Roussy, 94805, Villejuif, France.
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22
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Khan AO, Simms VA, Pike JA, Thomas SG, Morgan NV. CRISPR-Cas9 Mediated Labelling Allows for Single Molecule Imaging and Resolution. Sci Rep 2017; 7:8450. [PMID: 28814796 PMCID: PMC5559501 DOI: 10.1038/s41598-017-08493-x] [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: 03/09/2017] [Accepted: 06/29/2017] [Indexed: 12/25/2022] Open
Abstract
Single molecule imaging approaches like dSTORM and PALM resolve structures at 10–20 nm, and allow for unique insights into protein stoichiometry and spatial relationships. However, key obstacles remain in developing highly accurate quantitative single molecule approaches. The genomic tagging of PALM fluorophores through CRISPR-Cas9 offers an excellent opportunity for generating stable cell lines expressing a defined single molecule probe at endogenous levels, without the biological disruption and variability inherent to transfection. A fundamental question is whether these comparatively low levels of expression can successfully satisfy the stringent labelling demands of super-resolution SMLM. Here we apply CRISPR-Cas9 gene editing to tag a cytoskeletal protein (α-tubulin) and demonstrate a relationship between expression level and the subsequent quality of PALM imaging, and that spatial resolutions comparable to dSTORM can be achieved with CRISPR-PALM. Our approach shows a relationship between choice of tag and the total expression of labelled protein, which has important implications for the development of future PALM tags. CRISPR-PALM allows for nanoscopic spatial resolution and the unique quantitative benefits of single molecule localization microscopy through endogenous expression, as well as the capacity for super-resolved live cell imaging.
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Affiliation(s)
- Abdullah O Khan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Victoria A Simms
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Jeremy A Pike
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK. .,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.
| | - Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
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23
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Thomas SG, Poulter NS, Bem D, Finney B, Machesky LM, Watson SP. The actin binding proteins cortactin and HS1 are dispensable for platelet actin nodule and megakaryocyte podosome formation. Platelets 2017; 28:372-379. [PMID: 27778524 PMCID: PMC5274539 DOI: 10.1080/09537104.2016.1235688] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [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: 05/18/2016] [Revised: 07/06/2016] [Accepted: 08/22/2016] [Indexed: 11/08/2022]
Abstract
A dynamic, properly organised actin cytoskeleton is critical for the production and haemostatic function of platelets. The Wiskott Aldrich Syndrome protein (WASp) and Actin-Related Proteins 2 & 3 Complex (Arp2/3 complex) are critical mediators of actin polymerisation and organisation in many cell types. In platelets and megakaryocytes, these proteins have been shown to be important for proper platelet production and function. The cortactin family of proteins (Cttn & HS1) are known to regulate WASp-Arp2/3-mediated actin polymerisation in other cell types and so here we address the role of these proteins in platelets using knockout mouse models. We generated mice lacking Cttn and HS1 in the megakaryocyte/platelet lineage. These mice had normal platelet production, with platelet number, size and surface receptor profile comparable to controls. Platelet function was also unaffected by loss of Cttn/HS1 with no differences observed in a range of platelet function assays including aggregation, secretion, spreading, clot retraction or tyrosine phosphorylation. No effect on tail bleeding time or in thrombosis models was observed. In addition, platelet actin nodules, and megakaryocyte podosomes, actin-based structures known to be dependent on WASp and the Arp2/3 complex, formed normally. We conclude that despite the importance of WASp and the Arp2/3 complex in regulating F-actin dynamics in many cells types, the role of cortactin in their regulation appears to be fulfilled by other proteins in platelets.
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Affiliation(s)
- Steven G. Thomas
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Natalie S. Poulter
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Danai Bem
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Brenda Finney
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Laura M. Machesky
- Cancer Research UK Beatson Institute, College of Medical. Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Stephen P. Watson
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
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24
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Smith CW, Thomas SG, Raslan Z, Patel P, Byrne M, Lordkipanidzé M, Bem D, Meyaard L, Senis YA, Watson SP, Mazharian A. Mice Lacking the Inhibitory Collagen Receptor LAIR-1 Exhibit a Mild Thrombocytosis and Hyperactive Platelets. Arterioscler Thromb Vasc Biol 2017; 37:823-835. [PMID: 28336561 DOI: 10.1161/atvbaha.117.309253] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [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: 04/13/2016] [Accepted: 03/08/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is a collagen receptor that belongs to the inhibitory immunoreceptor tyrosine-based inhibition motif-containing receptor family. It is an inhibitor of signaling via the immunoreceptor tyrosine-based activation motif-containing collagen receptor complex, glycoprotein VI-FcRγ-chain. It is expressed on hematopoietic cells, including immature megakaryocytes, but is not detectable on platelets. Although the inhibitory function of LAIR-1 has been described in leukocytes, its physiological role in megakaryocytes and in particular in platelet formation has not been explored. In this study, we investigate the role of LAIR-1 in megakaryocyte development and platelet production by generating LAIR-1-deficient mice. APPROACH AND RESULTS Mice lacking LAIR-1 exhibit a significant increase in platelet counts, a prolonged platelet half-life in vivo, and increased proplatelet formation in vitro. Interestingly, platelets from LAIR-1-deficient mice exhibit an enhanced reactivity to collagen and the glycoprotein VI-specific agonist collagen-related peptide despite not expressing LAIR-1, and mice showed enhanced thrombus formation in the carotid artery after ferric chloride injury. Targeted deletion of LAIR-1 in mice results in an increase in signaling downstream of the glycoprotein VI-FcRγ-chain and integrin αIIbβ3 in megakaryocytes because of enhanced Src family kinase activity. CONCLUSIONS Findings from this study demonstrate that ablation of LAIR-1 in megakaryocytes leads to increased Src family kinase activity and downstream signaling in response to collagen that is transmitted to platelets, rendering them hyper-reactive specifically to agonists that signal through Syk tyrosine kinases, but not to G-protein-coupled receptors.
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Affiliation(s)
- Christopher W Smith
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Steven G Thomas
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Zaher Raslan
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Pushpa Patel
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Maxwell Byrne
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Marie Lordkipanidzé
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Danai Bem
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Linde Meyaard
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Yotis A Senis
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Steve P Watson
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.)
| | - Alexandra Mazharian
- From the Institute of Cardiovascular Sciences, College of Medical and Dental Sciences (C.W.S., S.G.T., Z.R., P.P., M.B., M.L., Y.A.S., S.P.W., A.M.), and Institute of Applied Health Research, College of Medical and Dental Sciences (D.B.), University of Birmingham, United Kingdom; and Laboratory of Translational Immunology, Department of Immunology, University Medical Center Utrecht, the Netherlands (L.M.).
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25
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Abstract
Platelets are small, anucleate blood cells which play an important role in haemostasis. Thrombocytopenia is a condition where the platelet count falls below 150×10(9)/l and patients suffering from severe forms of this condition can experience life-threatening bleeds requiring platelet transfusions. Platelets are produced from large progenitor cells called megakaryocytes which are found in the bone marrow. The process of megakaryocyte maturation and the formation of proplatelets are essential steps in the production of mature platelets and both depend heavily on the actin and microtubule cytoskeletons. Understanding these processes is important for the development of in vitro platelet production which will help to treat thrombocytopenia as well as produce model systems for studying platelet-associated disorders. This review will highlight some of the recent advances in our understanding of the role of the cytoskeleton in platelet production, especially the key molecules and signalling pathways that regulate actin and microtubule crosstalk.
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Affiliation(s)
- Natalie S Poulter
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Steven G Thomas
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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26
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Poulter NS, Pollitt AY, Davies A, Malinova D, Nash GB, Hannon MJ, Pikramenou Z, Rappoport JZ, Hartwig JH, Owen DM, Thrasher AJ, Watson SP, Thomas SG. Platelet actin nodules are podosome-like structures dependent on Wiskott-Aldrich syndrome protein and ARP2/3 complex. Nat Commun 2015; 6:7254. [PMID: 26028144 PMCID: PMC4458878 DOI: 10.1038/ncomms8254] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [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: 12/17/2014] [Accepted: 04/21/2015] [Indexed: 11/09/2022] Open
Abstract
The actin nodule is a novel F-actin structure present in platelets during early spreading. However, only limited detail is known regarding nodule organization and function. Here we use electron microscopy, SIM and dSTORM super-resolution, and live-cell TIRF microscopy to characterize the structural organization and signalling pathways associated with nodule formation. Nodules are composed of up to four actin-rich structures linked together by actin bundles. They are enriched in the adhesion-related proteins talin and vinculin, have a central core of tyrosine phosphorylated proteins and are depleted of integrins at the plasma membrane. Nodule formation is dependent on Wiskott–Aldrich syndrome protein (WASp) and the ARP2/3 complex. WASp−/− mouse blood displays impaired platelet aggregate formation at arteriolar shear rates. We propose actin nodules are platelet podosome-related structures required for platelet–platelet interaction and their absence contributes to the bleeding diathesis of Wiskott–Aldrich syndrome. During early platelet spreading a novel F-actin structure forms, called the actin nodule. Here Poulter et al. demonstrate that actin nodule formation depends on WASp and the Arp2/3 complex, and using super-resolution microscopy they show that nodules bear a structural resemblance to podosomes.
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Affiliation(s)
- Natalie S Poulter
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Alice Y Pollitt
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Amy Davies
- PSIBS doctoral training centre, School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Dessislava Malinova
- Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Gerard B Nash
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Mike J Hannon
- PSIBS doctoral training centre, School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Zoe Pikramenou
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Joshua Z Rappoport
- The Center for Advanced Microscopy and Nikon Imaging Center, Morton 2-681, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, Illinois 60611, USA
| | - John H Hartwig
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Dylan M Owen
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Adrian J Thrasher
- Molecular Immunology Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Stephen P Watson
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Steven G Thomas
- Centre for Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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27
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Pollitt AY, Poulter NS, Gitz E, Navarro-Nuñez L, Wang YJ, Hughes CE, Thomas SG, Nieswandt B, Douglas MR, Owen DM, Jackson DG, Dustin ML, Watson SP. Syk and Src family kinases regulate C-type lectin receptor 2 (CLEC-2)-mediated clustering of podoplanin and platelet adhesion to lymphatic endothelial cells. J Biol Chem 2014; 289:35695-710. [PMID: 25368330 PMCID: PMC4276840 DOI: 10.1074/jbc.m114.584284] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [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] [Indexed: 12/03/2022] Open
Abstract
The interaction of C-type lectin receptor 2 (CLEC-2) on platelets with Podoplanin on lymphatic endothelial cells initiates platelet signaling events that are necessary for prevention of blood-lymph mixing during development. In the present study, we show that CLEC-2 signaling via Src family and Syk tyrosine kinases promotes platelet adhesion to primary mouse lymphatic endothelial cells at low shear. Using supported lipid bilayers containing mobile Podoplanin, we further show that activation of Src and Syk in platelets promotes clustering of CLEC-2 and Podoplanin. Clusters of CLEC-2-bound Podoplanin migrate rapidly to the center of the platelet to form a single structure. Fluorescence lifetime imaging demonstrates that molecules within these clusters are within 10 nm of one another and that the clusters are disrupted by inhibition of Src and Syk family kinases. CLEC-2 clusters are also seen in platelets adhered to immobilized Podoplanin using direct stochastic optical reconstruction microscopy. These findings provide mechanistic insight by which CLEC-2 signaling promotes adhesion to Podoplanin and regulation of Podoplanin signaling, thereby contributing to lymphatic vasculature development.
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Affiliation(s)
- Alice Y Pollitt
- From the University of Birmingham, Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, Edgbaston, Birmingham B15 2TT, United Kingdom,
| | - Natalie S Poulter
- From the University of Birmingham, Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Eelo Gitz
- From the University of Birmingham, Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, Edgbaston, Birmingham B15 2TT, United Kingdom, the University Medical Center Utrecht, Department of Clinical Chemistry and Haematology, 3584 CX, Utrecht, The Netherlands
| | - Leyre Navarro-Nuñez
- From the University of Birmingham, Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Ying-Jie Wang
- the Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom
| | - Craig E Hughes
- From the University of Birmingham, Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Steven G Thomas
- From the University of Birmingham, Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Bernhard Nieswandt
- the Department of Experimental Biomedicine, University Hospital, University of Würzburg, Würzburg 97080, Germany
| | - Michael R Douglas
- the School of Immunity and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom, the Department of Neurology, Dudley Group National Health Service Foundation Trust, Dudley DY1 2HQ, United Kingdom
| | - Dylan M Owen
- the Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, United Kingdom
| | - David G Jackson
- the Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom
| | - Michael L Dustin
- the Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Diseases, University of Oxford, Headington OX3 7FY, United Kingdom, and the Department of Molecular Pathogenesis, New York University, Skirball Institute of Biomolecular Medicine, School of Medicine, New York University Langone Medical Center, New York, New York 10016
| | - Steve P Watson
- From the University of Birmingham, Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, Edgbaston, Birmingham B15 2TT, United Kingdom,
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Tibana RA, de Sousa NMF, da Cunha Nascimento D, Pereira GB, Thomas SG, Balsamo S, Simoes HG, Prestes J. Correlation between acute and chronic 24-hour blood pressure response to resistance training in adult women. Int J Sports Med 2014; 36:82-9. [PMID: 25144430 DOI: 10.1055/s-0034-1382017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The purpose of the present study was to correlate the acute and chronic decrease in blood pressure (BP) following resistance training (RT). 13 normotensive women (18-49 years) completed an acute whole body RT session with 3 sets of 10 repetitions at 60% 1RM and then 8 weeks of RT as follows: 3/week, 3 sets of 8-12 repetitions maximum. Systolic (SBP) and diastolic BP (DBP) were measured up to 60 min and 24 h following RT (acute and chronic). The greatest acute decrease of SBP (108.5±7.0 mmHg) and DBP (71.5±6.4 mmHg) values over the 60-min period were reduced compared to pre-exercise (117.3±11.7 and 79.3±8.2 mmHg, respectively; p<0.05). The chronic effect on resting BP was observed only for those presenting acute post-exercise hypotension (PEH). The change in both SBP and DBP following acute RT was correlated with the chronic change in resting SBP and DBP (r>0.5; p≤0.05). The change in 24 h BP after acute RT was correlated with the chronic reduction in SBP (r=0.74) and DBP (r=0.80). The magnitude of PEH is a promising candidate for the prediction of individual BP-related training efficacy.
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Affiliation(s)
- R A Tibana
- Graduation Program on Physical Education, Catholic University of Brasilia, Brasilia, Brazil
| | - N M F de Sousa
- Graduation Program Interunits in Bioengineering, Sao Carlos, Brazil
| | - D da Cunha Nascimento
- Graduation Program on Physical Education, Catholic University of Brasilia, Brasilia, Brazil
| | - G B Pereira
- Physical Education Departement, Federal University of Maranhao, Sao Luis, Brazil
| | - S G Thomas
- Physical Education, University of Toronto, Toronto, Canada
| | - S Balsamo
- Physical Education, UNIEURO Universitary Center, Brasilia, Brazil
| | - H G Simoes
- Physical Education, UNIEURO Universitary Center, Brasilia, Brazil
| | - J Prestes
- Physical Education, UNIEURO Universitary Center, Brasilia, Brazil
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Schachtner H, Calaminus SDJ, Thomas SG, Machesky LM. Podosomes in adhesion, migration, mechanosensing and matrix remodeling. Cytoskeleton (Hoboken) 2013; 70:572-89. [PMID: 23804547 DOI: 10.1002/cm.21119] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/07/2013] [Accepted: 06/13/2013] [Indexed: 12/30/2022]
Abstract
Cells use various actin-based motile structures to allow them to move across and through matrix of varying density and composition. Podosomes are actin cytoskeletal structures that form in motile cells and that mediate adhesion to substrate, migration, and other specialized functions such as transmigration through cell and matrix barriers. The podosome is a unique and interesting entity, which appears in the light microscope as an individual punctum, but is linked to other podosomes like a node on a network of the underlying cytoskeleton. Here, we discuss the signals that control podosome assembly and dynamics in different cell types and the actin organising proteins that regulate both the inner actin core and integrin-rich surrounding ring structures. We review the structure and composition of podosomes and also their functions in various cell types of both myeloid and endothelial lineage. We also discuss the emerging idea that podosomes can sense matrix stiffness and enable cells to respond to their environment.
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Affiliation(s)
- Hannah Schachtner
- CRUK Beatson Institute for Cancer Research and College of Medical, Veterinary and Life Sciences, Glasgow University, Garscube Campus, Switchback Rd., Bearsden, Glasgow, United Kingdom
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Schachtner H, Calaminus SDJ, Sinclair A, Monypenny J, Blundell MP, Leon C, Holyoake TL, Thrasher AJ, Michie AM, Vukovic M, Gachet C, Jones GE, Thomas SG, Watson SP, Machesky LM. Megakaryocytes assemble podosomes that degrade matrix and protrude through basement membrane. Blood 2013; 121:2542-52. [PMID: 23305739 DOI: 10.1182/blood-2012-07-443457] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [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: 01/27/2023] Open
Abstract
Megakaryocytes give rise to platelets via extension of proplatelet arms, which are released through the vascular sinusoids into the bloodstream. Megakaryocytes and their precursors undergo varying interactions with the extracellular environment in the bone marrow during their maturation and positioning in the vascular niche. We demonstrate that podosomes are abundant in primary murine megakaryocytes adherent on multiple extracellular matrix substrates, including native basement membrane. Megakaryocyte podosome lifetime and density, but not podosome size, are dependent on the type of matrix, with podosome lifetime dramatically increased on collagen fibers compared with fibrinogen. Podosome stability and dynamics depend on actin cytoskeletal dynamics but not matrix metalloproteases. However, podosomes degrade matrix and appear to be important for megakaryocytes to extend protrusions across a native basement membrane. We thus demonstrate for the first time a fundamental requirement for podosomes in megakaryocyte process extension across a basement membrane, and our results suggest that podosomes may have a role in proplatelet arm extension or penetration of basement membrane.
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Affiliation(s)
- Hannah Schachtner
- University of Glasgow College of Medical, Veterinary and Life Sciences and Beatson Institute for Cancer Research, Bearsden, Glasgow, UK
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Abstract
INTRODUCTION Research into work reintegration following cardiovascular disease onset is limited in its clinical and individual focus. There is no research examining worker experience in context during the return to work process. METHODS Qualitative case study method informed by applied ethnography. Worker experience was assessed through longitudinal in-depth interviews with 12 workers returning to work following disabling cardiac illness. Workplace context (Canadian auto manufacturing plant) was assessed through site visits and meetings with stakeholders including occupational health personnel. Data was analyzed using constant comparison and progressive coding. RESULTS Twelve men (43-63 years) participated in the study. Results revealed that unyielding production demands and performance monitoring pushed worker capacities and caused "insidious stress". Medical reassurance was important in the workers' decisions to return to work and stay on the job but medical restrictions were viewed as having limited relevance owing to limited understanding of work demands. Medical sanction was important for transient absence from the workplace as well as permanent disability. Cardiac rehabilitation programs were beneficial for lifestyle modification and building exercise capacity, but had limited benefit on work reintegration. Occupational health provided monitoring and support during work reintegration. CONCLUSIONS Medical reassurance can be an important influence on worker representations of disease threat. Medical advice as it pertained to work activities was less valued as it lacked considerations of work conditions. Cardiac rehabilitation lacked intensity and relevance to work demands. Occupational health was reassuring for workers and played an important role in developing return to work plans.
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Affiliation(s)
- F T O'Hagan
- Department of Psychology, Trent University, Peterborough, ON, K9J 7B8, Canada.
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Thomas SG, Calaminus SDJ, Machesky LM, Alberts AS, Watson SP. G-protein coupled and ITAM receptor regulation of the formin FHOD1 through Rho kinase in platelets. J Thromb Haemost 2011; 9:1648-51. [PMID: 21605332 DOI: 10.1111/j.1538-7836.2011.04357.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Kovacs EM, Verma S, Thomas SG, Yap AS. Tuba and N-WASP function cooperatively to position the central lumen during epithelial cyst morphogenesis. Cell Adh Migr 2011; 5:344-50. [PMID: 21677511 DOI: 10.4161/cam.5.4.16717] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The process of epithelial lumenogenesis requires coordination of a network of signaling machinery communicated to each cell through subsequent cell divisions. Formation of a single hollow lumen has previously been shown to require Tuba, a Cdc42 GEF, for Cdc42 activation and correct spindle orientation. Using a Caco-2 model of lumenogenesis, we show that knockdown (KD) of the actin regulator N-WASP, causes a multilumen phenotype similar to Tuba KD. Defects in lumenogenesis in Tuba KD and N-WASP KD cells are observed at the two cell stage with inappropriate marking of the pre-apical patch (PAP) - the precursor to lumen formation. Strikingly, both Tuba and N-WASP depend on each other for localization to the PAP. We conclude that N-WASP functions cooperatively with Tuba to facilitate lumenogenesis and this requires the polyproline region of N-WASP.
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Affiliation(s)
- Eva M Kovacs
- Division of Molecular Cell Biology, Institute for Molecular Bioscience, The University of Queensland-St. Lucia, QLD, Australia
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Abstract
INTRODUCTION Tracheobronchitis is a rare extraintestinal manifestation of ulcerative colitis (UC) and is often mis-diagnosed and treated as asthma. OBJECTIVE We report a case of tracheobromchitis in a patient with long-standing UC, who had been treated for asthma for many years with a poor response to standard asthma management. Only very few cases are reported and in the majority of them tracheobronchitis developed after colectomy. METHODS Subsequent investigations of unremitting respiratory symptoms in our patient revealed tracheobronchitis. His UC remained quiescent for more than 20 years on medical treatment having never required a bowel resection. RESULTS On thoroughly investigating the aetiology for his pulmonary pathology, it was thought to be an extraintestinal manifestation of UC, which makes this case noteworthy. CONCLUSION Pulmonary complications can develop many years after the diagnosis of inflammatory bowel disease, without any sign of disease activity. In such cases awareness and a high index of suspicion are important to ensure early diagnosis and treatment, and further investigations to detect large airway disease is warranted. The pulmonary manifestations tend to respond well to steroid therapy, which may prevent or ameliorate permanent lung damage.
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Affiliation(s)
- Soma Kar
- Department of Respiratory Medicine, Calderdale Royal Hospital, Halifax, West Yorkshire, UK.
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Dijkstra C, Adams E, Bhattacharya A, Page AF, Anthony P, Kourmpetli S, Power JB, Lowe KC, Thomas SG, Hedden P, Phillips AL, Davey MR. Over-expression of a gibberellin 2-oxidase gene from Phaseolus coccineus L. enhances gibberellin inactivation and induces dwarfism in Solanum species. Plant Cell Rep 2008; 27:463-70. [PMID: 17999064 DOI: 10.1007/s00299-007-0471-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 10/08/2007] [Accepted: 10/19/2007] [Indexed: 05/24/2023]
Abstract
Gibberellins (GAs) are endogenous hormones that play a predominant role in regulating plant stature by increasing cell division and elongation in stem internodes. The product of the GA 2-oxidase gene from Phaseolus coccineus (PcGA2ox1) inactivates C(19)-GAs, including the bioactive GAs GA(1 )and GA(4), by 2beta-hydroxylation, reducing the availability of these GAs in plants. The PcGA2ox1 gene was introduced into Solanum melanocerasum and S. nigrum (Solanaceae) by Agrobacterium-mediated transformation with the aim of decreasing the amounts of bioactive GA in these plants and thereby reducing their stature. The transgenic plants exhibited a range of dwarf phenotypes associated with a severe reduction in the concentrations of the biologically active GA(1) and GA(4). Flowering and fruit development were unaffected. The transgenic plants contained greater concentrations of chlorophyll b (by 88%) and total chlorophyll (11%), although chlorophyll a and carotenoid contents were reduced by 8 and 50%, respectively. This approach may provide an alternative to the application of chemical growth retardants for reducing the stature of plants, particularly ornamentals, in view of concerns over the potential environmental and health hazards of such compounds.
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Affiliation(s)
- C Dijkstra
- Plant Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK
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Abstract
BACKGROUND The platelet cytoskeleton mediates the dramatic change in platelet morphology that takes place upon activation and stabilizes thrombus formation. The Arp2/3 complex plays a vital role in these processes, providing the protrusive force for lamellipodia formation. The Arp2/3 complex is highly regulated by a number of actin-binding proteins including the haematopoietic-specific protein HS1 and its homologue cortactin. The present study investigates the role of HS1 in platelets using HS1-/- mice. RESULTS The present results demonstrate that HS1 is not required for platelet activation, shape change or aggregation. Platelets from HS1-/- mice spread normally on a variety of adhesion proteins and have normal F-actin and Arp2/3 complex distributions. Clot retraction, an actin-dependent process, is also normal in these mice. Platelet aggregation and secretion is indistinguishable between knock out and littermates and there is no increase in bleeding using the tail bleeding assay. CONCLUSION This study concludes that HS1 does not play a major role in platelet function. It is possible that a role for HS1 is masked by the presence of cortactin.
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Affiliation(s)
- Steven G Thomas
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Simon DJ Calaminus
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Jocelyn M Auger
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Stephen P Watson
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Laura M Machesky
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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Bellissimo N, Desantadina MV, Pencharz PB, Berall GB, Thomas SG, Anderson GH. A comparison of short-term appetite and energy intakes in normal weight and obese boys following glucose and whey-protein drinks. Int J Obes (Lond) 2007; 32:362-71. [PMID: 17700578 DOI: 10.1038/sj.ijo.0803709] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To compare the effect of glucose and whey-protein preloads on satiety and food intake (FI) as affected by time to the next meal and body composition in normal weight (NW) and obese (OB) boys. DESIGN Cross-sectional clinical intervention study of the effect of caloric preloads on FI control in boys. SUBJECTS Seventeen NW (body mass index (BMI)=18.9+/-0.5 kg/m(2); age=12.2+/-0.3 years) and 17 OB boys (BMI=25.8+/-0.9 kg/m(2); age=11.4+/-0.3 years) (Experiment 1) and 12 NW boys (BMI=18.6+/-0.6 kg/m(2); age=12.1+/-0.3 years) (Experiment 2). MEASUREMENTS On three separate mornings and in random order each of the boys consumed a noncaloric sweetened preload, glucose (837 kJ) or whey protein (837 kJ) (Experiment 1) or noncaloric preload, glucose (1.0 g/kg) or whey protein (1.0 g/kg) (Experiment 2) made up to 250 ml with water 2 h after the consumption of a fixed breakfast. Food intake from a pizza meal was measured 30 min (Experiment 1) or 60 min (Experiment 2) later. RESULTS In Experiment 1, glucose suppressed FI (mean kJ+/-s.e.m.) in NW (3126+/-304) and OB boys (3116+/-286) compared with the control (NW, 4015+/-337 and OB, 3791+/-255). Whey protein suppressed FI in NW, but not in OB boys. Body weight, fat-mass and fat-free mass were positively associated with FI after all treatments in NW, but was not related to FI in OB boys. In Experiment 2, FI was suppressed by whey protein (2683+/-367) more than by glucose (3107+/-294) or the control (3585+/-361). CONCLUSION NW and OB boys respond differently to whey-protein preloads, with time to next meal a factor in the response to both glucose and protein preloads.
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Affiliation(s)
- N Bellissimo
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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Thomas SG, Huang S, Li S, Staiger CJ, Franklin-Tong VE. Actin depolymerization is sufficient to induce programmed cell death in self-incompatible pollen. ACTA ACUST UNITED AC 2006; 174:221-9. [PMID: 16831890 PMCID: PMC2064182 DOI: 10.1083/jcb.200604011] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Self-incompatibility (SI) prevents inbreeding through specific recognition and rejection of incompatible pollen. In incompatible Papaver rhoeas pollen, SI triggers a Ca2+ signaling cascade, resulting in the inhibition of tip growth, actin depolymerization, and programmed cell death (PCD). We investigated whether actin dynamics were implicated in regulating PCD. Using the actin-stabilizing and depolymerizing drugs jasplakinolide (Jasp) and latrunculin B, we demonstrate that changes in actin filament levels or dynamics play a functional role in initiating PCD in P. rhoeas pollen, triggering a caspase-3–like activity. Significantly, SI-induced PCD in incompatible pollen was alleviated by pretreatment with Jasp. This represents the first account of a specific causal link between actin polymerization status and initiation of PCD in a plant cell and significantly advances our understanding of the mechanisms involved in SI.
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Affiliation(s)
- Steven G Thomas
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, England, UK
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Abstract
BACKGROUND/AIMS Fibre-optic confocal imaging in vivo is a new approach in the assessment of human skin. The objective is to describe a novel instrument and its operation and use in combination with fluorophores. METHODS The Stratum is a fibre-optic fluorescence confocal microscope especially developed for the study of skin and mucous membranes. The system is flexible and any body site can be studied with a hand-held scanner. The light source is a 488 nm argon ion laser. Horizontal (en face) images of the epidermis and outer dermis are produced with cellular resolution. Magnification is approximately 1000 x . Fluorescein sodium is routinely used as fluorophore (intradermal injection or application to the skin surface). This fluorophore is safe for human use in vivo, but other substances (rhodamine B, Acridine Orange, green fluorescent protein, curcumin) have also been studied. RESULTS The instrument produces sharp images of epidermal cell layers from the epidermal surface to the sub-papillary dermis, with sub-cellular resolution. The scanner is flexible in use. The technique of intradermal fluorophore injection requires some skill. CONCLUSIONS We consider this fibre-optic instrument a potentially important tool in skin research for non-invasive optical biopsy of primarily the epidermis. Present use is focussed on research applications, where the fluorophore distribution in the skin may illustrate morphological changes in the epidermis.
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Affiliation(s)
- Christian Suihko
- Department of Dermatology, Linköping University Hospital, Linköping, Sweden.
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Abstract
Sexual reproduction in many angiosperm plants involves self-incompatibility (SI), which is one of the most important mechanisms to prevent inbreeding. SI is genetically controlled by the S-locus, and involves highly specific interactions during pollination between pollen and the pistil on which it lands. This results in the rejection of incompatible ('self') pollen, whereas compatible ('non-self') pollen is allowed to fertilize the plant. In Papaver rhoeas, S-proteins encoded by the stigma component of the S-locus interact with incompatible pollen, triggering a Ca2+-dependent signalling network, resulting in the inhibition of pollen-tube growth. Programmed cell death (PCD) is a mechanism used by many organisms to destroy unwanted cells in a precisely regulated manner. Here we show that PCD is triggered by SI in an S-specific manner in incompatible pollen. This provides a demonstration of a SI system using PCD, revealing a novel mechanism to prevent self-fertilization. Furthermore, our data reveal that the response is biphasic; rapid inhibition of pollen-tube growth is followed by PCD, which is involved in a later 'decision-making' phase, making inhibition irreversible.
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Affiliation(s)
- Steven G Thomas
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Swindle LD, Thomas SG, Freeman M, Delaney PM. View of Normal Human Skin In Vivo as Observed Using Fluorescent Fiber-Optic Confocal Microscopic Imaging. J Invest Dermatol 2003; 121:706-12. [PMID: 14632185 DOI: 10.1046/j.1523-1747.2003.12477.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [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: 11/20/2022]
Abstract
Fluorescence confocal scanning laser microscopy, using a miniaturized handheld scanner, was performed to visualize the microscopic architecture of normal human epidermis in vivo. Fluorescein sodium (approximately 20 microL of 0.2% wt/vol) was administered via intradermal injection to normal skin on the volar forearm of 22 patients. The skin was imaged continuously from 1 to 15 min after injection. Fluorescein was excited at 488 nm and the fluorescent emission was detected at > 505 nm. In each subject, a series of images was collected at increasing depth, from superficial stratum corneum to papillary dermis. Features observed in confocal images were compared to those seen in hematoxylin- and eosin-stained sections of skin. The confocal images demonstrated the architecture of superficial skin in the horizontal plane. There was a transition in keratinocyte size, shape, and morphology with progressive imaging into the deeper epidermal layers. Superficial dermis and microscopic capillaries with blood flow were easily observed. The morphologic patterns associated with the major cell types of the epidermis were consistent with those known from conventional histology. We report the ability of in vivo fluorescence point scanning laser confocal microscopy to produce real-time, high-resolution images of the microscopic architecture of normal human epidermis using a noninvasive imaging technology.
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McLaren WJ, Anikijenko P, Thomas SG, Delaney PM, King RG. In vivo detection of morphological and microvascular changes of the colon in association with colitis using fiberoptic confocal imaging (FOCI). Dig Dis Sci 2002; 47:2424-33. [PMID: 12452374 DOI: 10.1023/a:1020631220599] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Using a well-established rodent model of inflammatory bowel disease (IBD), the present study examined changes in the microvasculature of the colonic mucosa in association with ulcerative colitis (UC). The results were compared to microscopic alterations in tissue morphology to establish a temporal relationship between microcirculatory dysfunction and IBD pathology. Mild colitis was induced in rats by the oral consumption of 5% dextran sulfate sodium (DSS) in drinking water. Control animals were provided with water ad libitum. After 3, 5, and 7 days of oral ingestion of DSS, anesthetized rats were laparotomized. The mucosal surface of the distal colon was then examined using fiber optic confocal imaging (FOCI; excitation 488 nm argon ion laser, detection above 515 nm). Changes in the mucosal architecture were examined following the topical application of the fluorescent dye, tetracycline hydrochloride. Tetracycline hydrochloride, an antibiotic used widely in clinical medicine, enabled imaging of the crypts at the surface of the mucosa. Spatial changes in the microvascular structure were assessed following the intravenous administration of fluorescein isothiocyanate dextran (FITC-dextran). Confocal images were correlated with clinical parameters, including weight loss, occult blood, and stool consistency. Attenuation of the colonic epithelium was detected on day 3 colitis. Morphological changes including crypt loss, crypt distortion, and inflammatory cell infiltrate were detected on day 5 and day 7 colitis. Dual channel imaging showed the mucosal capillary network outlining the stromal confines of the mucus-secreting glands in control tissue. Experimental colitis resulted in diffuse hypervascularity and tortuosity of the capillary vessels. Evidence of increased vessel leakiness (leakage of FITC-dextran from the lumen) was first detected on day 5 colitis. Complete disruption of the normal honeycomb pattern of the vessels and capillary dilation was evident after 7 days of DSS ingestion. These findings suggest that the pathogenesis of ulcerative colitis is associated with changes in the vascular architecture as demonstrated in vivo using confocal microscopy.
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Affiliation(s)
- Wendy J McLaren
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia
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Anikijenko P, Vo LT, Murr ER, Carrasco J, McLaren WJ, Chen Q, Thomas SG, Delaney PM, King RG. In vivo detection of small subsurface melanomas in athymic mice using noninvasive fiber optic confocal imaging. J Invest Dermatol 2001; 117:1442-8. [PMID: 11886506 DOI: 10.1046/j.0022-202x.2001.01592.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [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: 01/12/2023]
Abstract
Fiber optic confocal imaging, following intravenous administration of fluorescently labeled antibodies and Texas Red-dextran, enabled in vivo detection of melanoma and surrounding blood vessels in athymic mice. Human melanoma cells (three cell lines) and cultured normal human skin cells were implanted intradermally into the haunch skin of anesthetized athymic BALB/C mice and allowed to grow to a maximum size of 2 mm diameter. Using three different fluorescein-isothiocyanate-labeled antimelanoma antibodies, single channel confocal images of melanoma cells were obtained in vivo. Using noninvasive techniques, the overall in vivo melanoma detection rate for tumors within 0.2 mm of the skin surface was 84% (27 of 32 tumors). Normal cultured human skin cells were found to have little or no fluorescence after administration of the fluorescein-isothiocyanate-labeled antibodies and tumors were not labeled by an isotype control antibody. Dual channel imaging of the implanted melanoma tumor and surrounding dermal vasculature in vivo showed increased blood vessel density at the melanoma site. Conventional immunoperoxidase histology confirmed that fiber optic confocal imaging was able to detect melanoma tumors up to 0.2 mm below the skin surface, in vivo.
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Affiliation(s)
- P Anikijenko
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia
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Diskin CJ, Gupta RB, Ravis W, Stokes TJ, Dansby LM, Carter TB, Thomas SG. Edema, oncotic pressure, and free entropy: novel considerations for the treatment of edema through attention to thermodynamics. Nephron Clin Pract 2000; 78:131-8. [PMID: 9496727 DOI: 10.1159/000044900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [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: 11/19/2022] Open
Abstract
Over 170 years after Richard Bright and a century after Ernest H. Starling, the development, location, and severity of edema in patients with renal impairment continue to baffle the predictions of most nephrologists. While much of the phenomenon can be explained by levels of serum proteins, or hydrostatic pressures, there are stunning exceptions well known to any practicing nephrologist. Some of the derangement is undoubtedly due to unmeasured but well-known variables, such as membrane permeability; however, other factors such as free entropy of plasma are also clearly involved. The study of other polyelectrolyte colloids, similar to plasma proteins, for industrial purposes has led to the identification of various phenomena such as counterion condensation that can result in loss of entropy and consequently osmotic pressure. Variables known to result in a loss of free entropy, such as pH, oxidation products and ligand binding, are discussed. Older equations developed by van't Hoff and Donnan might require replacement by newer mathematical models such as the nonlinear Poisson-Boltzmann equation or the Monte Carlo simulator. Attempts to restore free entropy to plasma would be a more physiological treatment of edema than diuretic use. Implications are noted for future drug development to treat edema.
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Affiliation(s)
- C J Diskin
- Hypertension, Nephrology, Dialysis and Transplantation Clinic, Opelika, Ala 36802, USA
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Diskin CJ, Stokes TJ, Thomas SG, Ravis W, Lock S, Thomas J, Panus LW, Dansby L, Carter T. An analysis of the effect of routine medications on hemodialysis vascular access survival. Nephron Clin Pract 2000; 78:365-8. [PMID: 9546712 DOI: 10.1159/000044961] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Curtis IS, Ward DA, Thomas SG, Phillips AL, Davey MR, Power JB, Lowe KC, Croker SJ, Lewis MJ, Magness SL, Hedden P. Induction of dwarfism in transgenic Solanum dulcamara by over-expression of a gibberellin 20-oxidase cDNA from pumpkin. Plant J 2000; 23:329-338. [PMID: 10929126 DOI: 10.1046/j.1365-313x.2000.00784.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The gibberellin (GA) 20-oxidase (CmGA20ox1) from immature pumpkin seed produces predominantly inactive tricarboxylic acid GAs. We expressed CmGA20ox1 under the control of the CaMV 35S promoter in Solanum dulcamara to assess the usefulness of this gene for reducing GA content in transgenic plants. All transgenic plants obtained were semi-dwarfs with smaller, deep-green leaves and highly pigmented stems compared to the wild-type. Such transformants flowered earlier than the wild-type plants and produced more fruit and more seeds per fruit. The transgene was efficiently expressed, producing high levels of CmGA20ox1 transcript and protein. Furthermore, the concentration of GA(1) was reduced in leaves of the transformants to approximately 20% or less of that in the wild-type and to about 40% or less in stems. The concentrations of other 13-hydroxylated GAs were also reduced, except for the tricarboxylic acid, GA(17), which accumulated in the transformants due to 13-hydroxylation of GA(25). By contrast, the concentrations of non-13-hydroxylated GAs, GA(4) and GA(34), were not consistently reduced, indicating that the effect of expressing the pumpkin gene may not be predictable. Transcript abundance for a native GA 20-oxidase gene was higher in the leaves and stems of S. dulcamara transformed with the pumpkin gene than in wild-type, reflecting the feedback control of 20-oxidase gene expression that serves as a homeostatic mechanism for GAs.
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Affiliation(s)
- I S Curtis
- Plant Science Division, School of Biological Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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Abstract
FMRFamide-like peptide (FLP) amino acid sequences have been collected and statistically analyzed. FLP amino acid composition as a function of position in the peptide is graphically presented for several major phyla. Results of total amino acid composition and frequencies of pairs of FLP amino acids have been computed and compared with corresponding values from the entire GenBank protein sequence database. The data for pairwise distributions of amino acids should help in future structure-function studies of FLPs. To aid in future peptide discovery, a computer program and search protocol was developed to identify FLPs from the GenBank protein database without the use of keywords.
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Affiliation(s)
- E Espinoza
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville 32610, USA
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Woodhouse LJ, Asa SL, Thomas SG, Ezzat S. Measures of submaximal aerobic performance evaluate and predict functional response to growth hormone (GH) treatment in GH-deficient adults. J Clin Endocrinol Metab 1999; 84:4570-7. [PMID: 10599721 DOI: 10.1210/jcem.84.12.6196] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The impact of GH on functional performance in GH-deficient adults is not well understood. To investigate the effects of GH on skeletal muscle, physical, and functional capacity, we randomized 28 GH-deficient adults to receive 3 months of recombinant human GH [rhGH: somatotropin, 6.25 microg/kg lean body mass (LBM) for 1 month, 12.5 microg/kg LBM thereafter] in a double-blind placebo-controlled crossover trial. We measured muscle fiber type, size, and insulin-like growth factor I messenger RNA, aerobic capacity [maximal oxygen uptake (VO2max), ventilation threshold (VeT)], isokinetic strength, oxygen-cost-of-walking at normal and fast speeds, and fatigue determined by the profile of mood states questionnaire. As expected, GH treatment decreased body fat, increased LBM, increased muscle fiber size, and increased muscle insulin-like growth factor-I messenger RNA 5-fold; however, muscle strength remained unchanged. At baseline, VeT occurred at a high percentage of maximal VO2max (73.3% +/-2.6) because of low VO2max (1.74+/-0.1 L/min or 20.7+/-1.3 mL/ kg x min). Walking required high oxygen consumptions representing from 83+/-4% of VeT at normal speeds to 120+/-5% of VeT at fast speeds. After rhGH, there was a significant (P = 0.03) increase in VeT (18%), compared with placebo. This was paralleled by a nonsignificant rise in VO2max. Functionally, rhGH treatment decreased the oxygen cost of walking, relative to VeT, at normal (14% decrease, P = 0.019) and fast (21% decrease, P = 0.004) SPW speeds. A 3-variable model (baseline fast SPW speed, VeT/VO2max, and VeT) accounted for 39% of the variance of change in self-reported fatigue. These data indicate that GH-deficient adults require a high fraction of VeT for daily activities, explaining the perception of increased fatigue and impaired physical performance. The actions ofrhGH on muscle fiber size translate into physiological improvement in submaximal aerobic capacity and result in functional improvement in walking ability but do not necessarily alter strength. Thus, measures of effort-independent submaximal aerobic performance provide novel objective determinants of functional impairment and fatigue and can be used to evaluate and predict response to GH treatment.
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Affiliation(s)
- L J Woodhouse
- Department of Physical Therapy, The University of Toronto, Ontario, Canada
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Thomas SG. Kid wrists at risk. Computer injuries can start at home or in the classroom. US News World Rep 1999; 127:62-3. [PMID: 10538637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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