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Bazaz R, Marriott HM, Wright C, Chamberlain J, West LE, Gelsthorpe C, Heath PR, Maleki-Dizaji A, Francis SE, Dockrell DH. Transient increase in atherosclerotic plaque macrophage content following Streptococcus pneumoniae pneumonia in ApoE-deficient mice. Front Cell Infect Microbiol 2023; 13:1090550. [PMID: 37033482 PMCID: PMC10076735 DOI: 10.3389/fcimb.2023.1090550] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
Introduction Despite epidemiological associations between community acquired pneumonia (CAP) and myocardial infarction, mechanisms that modify cardiovascular disease during CAP are not well defined. In particular, largely due to a lack of relevant experimental models, the effect of pneumonia on atherosclerotic plaques is unclear. We describe the development of a murine model of the commonest cause of CAP, Streptococcus pneumoniae pneumonia, on a background of established atherosclerosis. We go on to use our model to investigate the effects of pneumococcal pneumonia on atherosclerosis. Methods C57BL/6J and ApoE-/- mice were fed a high fat diet to promote atherosclerotic plaque formation. Mice were then infected with a range of S. pneumoniae serotypes (1, 4 or 14) with the aim of establishing a model to study atherosclerotic plaque evolution after pneumonia and bacteremia. Laser capture microdissection of plaque macrophages enabled transcriptomic analysis. Results Intratracheal instillation of S. pneumoniae in mice fed a cholate containing diet resulted in low survival rates following infection, suggestive of increased susceptibility to severe infection. Optimization steps resulted in a final model of male ApoE-/- mice fed a Western diet then infected by intranasal instillation of serotype 4 (TIGR4) S. pneumoniae followed by antibiotic administration. This protocol resulted in high rates of bacteremia (88.9%) and survival (88.5%). Pneumonia resulted in increased aortic sinus plaque macrophage content 2 weeks post pneumonia but not at 8 weeks, and no difference in plaque burden or other plaque vulnerability markers were found at either time point. Microarray and qPCR analysis of plaque macrophages identified downregulation of two E3 ubiquitin ligases, Huwe1 and Itch, following pneumonia. Treatment with atorvastatin failed to alter plaque macrophage content or other plaque features. Discussion Without antibiotics, ApoE-/- mice fed a high fat diet were highly susceptible to mortality following S. pneumoniae infection. The major infection associated change in plaque morphology was an early increase in plaque macrophages. Our results also hint at a role for the ubiquitin proteasome system in the response to pneumococcal infection in the plaque microenvironment.
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Affiliation(s)
- Rohit Bazaz
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
- Department of Infectious Diseases, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Helen M. Marriott
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Carl Wright
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Janet Chamberlain
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Laura E. West
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Catherine Gelsthorpe
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Paul R. Heath
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | | | - Sheila E. Francis
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - David H. Dockrell
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
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2
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Herman KD, Wright CG, Marriott HM, McCaughran SC, Bowden KA, Collins MO, Renshaw SA, Prince LR. The EGFR/ErbB inhibitor neratinib modifies the neutrophil phosphoproteome and promotes apoptosis and clearance by airway macrophages. Front Immunol 2022; 13:956991. [PMID: 35967296 PMCID: PMC9371615 DOI: 10.3389/fimmu.2022.956991] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/05/2022] Open
Abstract
Dysregulated neutrophilic inflammation can be highly destructive in chronic inflammatory diseases due to prolonged neutrophil lifespan and continual release of histotoxic mediators in inflamed tissues. Therapeutic induction of neutrophil apoptosis, an immunologically silent form of cell death, may be beneficial in these diseases, provided that the apoptotic neutrophils are efficiently cleared from the tissue. Previous research in our group identified ErbB inhibitors as able to induce neutrophil apoptosis and reduce neutrophilic inflammation both in vitro and in vivo. Here, we extend that work using a clinical ErbB inhibitor, neratinib, which has the potential to be repurposed in inflammatory diseases. We show that neratinib reduces neutrophilic migration o an inflammatory site in zebrafish larvae. Neratinib upregulates efferocytosis and reduces the number of persisting neutrophil corpses in mouse models of acute, but not chronic, lung injury, suggesting that the drug may have therapeutic benefits in acute inflammatory settings. Phosphoproteomic analysis of human neutrophils shows that neratinib modifies the phosphorylation of proteins regulating apoptosis, migration, and efferocytosis. This work identifies a potential mechanism for neratinib in treating acute lung inflammation by upregulating the clearance of dead neutrophils and, through examination of the neutrophil phosphoproteome, provides important insights into the mechanisms by which this may be occurring.
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Affiliation(s)
- Kimberly D Herman
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom.,Department of Infection, Immunity and Cardiovascular Disease and The Bateson Centre, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Carl G Wright
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Helen M Marriott
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Sam C McCaughran
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Kieran A Bowden
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Mark O Collins
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Stephen A Renshaw
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom.,Department of Infection, Immunity and Cardiovascular Disease and The Bateson Centre, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Lynne R Prince
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom
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3
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Marsh EK, Prestwich EC, Williams L, Hart AR, Muir CF, Parker LC, Jonker MR, Heijink IH, Timens W, Fife M, Hussell T, Hershenson MB, Bentley JK, Sun SC, Barksby BS, Borthwick LA, Stewart JP, Sabroe I, Dockrell DH, Marriott HM. Pellino-1 Regulates the Responses of the Airway to Viral Infection. Front Cell Infect Microbiol 2020; 10:456. [PMID: 32984077 PMCID: PMC7488214 DOI: 10.3389/fcimb.2020.00456] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/24/2020] [Indexed: 01/02/2023] Open
Abstract
Exposure to respiratory pathogens is a leading cause of exacerbations of airway diseases such as asthma and chronic obstructive pulmonary disease (COPD). Pellino-1 is an E3 ubiquitin ligase known to regulate virally-induced inflammation. We wished to determine the role of Pellino-1 in the host response to respiratory viruses in health and disease. Pellino-1 expression was examined in bronchial sections from patients with GOLD stage two COPD and healthy controls. Primary bronchial epithelial cells (PBECs) in which Pellino-1 expression had been knocked down were extracellularly challenged with the TLR3 agonist poly(I:C). C57BL/6 Peli1-/- mice and wild type littermates were subjected to intranasal infection with clinically-relevant respiratory viruses: rhinovirus (RV1B) and influenza A. We found that Pellino-1 is expressed in the airways of normal subjects and those with COPD, and that Pellino-1 regulates TLR3 signaling and responses to airways viruses. In particular we observed that knockout of Pellino-1 in the murine lung resulted in increased production of proinflammatory cytokines IL-6 and TNFα upon viral infection, accompanied by enhanced recruitment of immune cells to the airways, without any change in viral replication. Pellino-1 therefore regulates inflammatory airway responses without altering replication of respiratory viruses.
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Affiliation(s)
- Elizabeth K. Marsh
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom,Human Sciences Research Centre, College of Life and Natural Sciences, University of Derby, Derby, United Kingdom
| | - Elizabeth C. Prestwich
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
| | - Lynne Williams
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
| | - Amber R. Hart
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
| | - Clare F. Muir
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
| | - Lisa C. Parker
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
| | - Marnix R. Jonker
- Department of Pathology and Medical Biology, University of Groningen, University Medical Centre Groningen, Groningen, Netherlands
| | - Irene H. Heijink
- Department of Pathology and Medical Biology, University of Groningen, University Medical Centre Groningen, Groningen, Netherlands
| | - Wim Timens
- Department of Pathology and Medical Biology, University of Groningen, University Medical Centre Groningen, Groningen, Netherlands
| | - Mark Fife
- Manchester Collaborative Centre for Inflammation Research, Core Technology Facility, University of Manchester, Manchester, United Kingdom
| | - Tracy Hussell
- Manchester Collaborative Centre for Inflammation Research, Core Technology Facility, University of Manchester, Manchester, United Kingdom
| | - Marc B. Hershenson
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, United States
| | - J. Kelley Bentley
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Shao-Cong Sun
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Ben S. Barksby
- Newcastle Fibrosis Research Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Lee A. Borthwick
- Newcastle Fibrosis Research Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - James P. Stewart
- Department of Infection Biology, University of Liverpool, Liverpool, United Kingdom
| | - Ian Sabroe
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
| | - David H. Dockrell
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom,MRC/UoE Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Helen M. Marriott
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom,*Correspondence: Helen M. Marriott
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4
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Fenaroli F, Robertson JD, Scarpa E, Gouveia VM, Di Guglielmo C, De Pace C, Elks PM, Poma A, Evangelopoulos D, Canseco JO, Prajsnar TK, Marriott HM, Dockrell DH, Foster SJ, McHugh TD, Renshaw SA, Martí JS, Battaglia G, Rizzello L. Polymersomes Eradicating Intracellular Bacteria. ACS Nano 2020; 14:8287-8298. [PMID: 32515944 DOI: 10.1021/acsnano.0c01870] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [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] [Indexed: 05/15/2023]
Abstract
Mononuclear phagocytes such as monocytes, tissue-specific macrophages, and dendritic cells are primary actors in both innate and adaptive immunity. These professional phagocytes can be parasitized by intracellular bacteria, turning them from housekeepers to hiding places and favoring chronic and/or disseminated infection. One of the most infamous is the bacteria that cause tuberculosis (TB), which is the most pandemic and one of the deadliest diseases, with one-third of the world's population infected and an average of 1.8 million deaths/year worldwide. Here we demonstrate the effective targeting and intracellular delivery of antibiotics to infected macrophages both in vitro and in vivo, using pH-sensitive nanoscopic polymersomes made of PMPC-PDPA block copolymer. Polymersomes showed the ability to significantly enhance the efficacy of the antibiotics killing Mycobacterium bovis, Mycobacterium tuberculosis, and another established intracellular pathogen, Staphylococcus aureus. Moreover, they demonstrated to easily access TB-like granuloma tissues-one of the harshest environments to penetrate-in zebrafish models. We thus successfully exploited this targeting for the effective eradication of several intracellular bacteria, including M. tuberculosis, the etiological agent of human TB.
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Affiliation(s)
| | - James D Robertson
- Department of Biomedical Science, University of Sheffield, S10 2TN Sheffield, U.K
- The Bateson Centre, University of Sheffield, Firth Court, S10 2TN Sheffield, U.K
| | - Edoardo Scarpa
- Department of Chemistry, University College London, WC1H 0AJ London, U.K
| | - Virginia M Gouveia
- Department of Chemistry, University College London, WC1H 0AJ London, U.K
| | - Claudia Di Guglielmo
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Cesare De Pace
- Department of Chemistry, University College London, WC1H 0AJ London, U.K
- The EPSRC/Jeol Centre for Liquid Phase Electron Microscopy, University College London, WC1H 0AJ London, U.K
| | - Philip M Elks
- Department of Biomedical Science, University of Sheffield, S10 2TN Sheffield, U.K
- Department of Infection, Immunity, and Cardiovascular Disease, University of Sheffield Medical School, S10 2JF Sheffield, U.K
| | - Alessandro Poma
- Department of Chemistry, University College London, WC1H 0AJ London, U.K
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, WC1X 8LD London, U.K
| | - Dimitrios Evangelopoulos
- Department of Clinical Microbiology, University College London, Royal Free Hospital, NW3 2PF London, U.K
| | - Julio Ortiz Canseco
- Department of Clinical Microbiology, University College London, Royal Free Hospital, NW3 2PF London, U.K
| | - Tomasz K Prajsnar
- The Florey Institute, University of Sheffield, S10 2TN Sheffield, U.K
- Department of Molecular Biology and Biotechnology, University of Sheffield, S10 2TN Sheffield, U.K
| | - Helen M Marriott
- Department of Infection, Immunity, and Cardiovascular Disease, University of Sheffield Medical School, S10 2JF Sheffield, U.K
- The Florey Institute, University of Sheffield, S10 2TN Sheffield, U.K
| | - David H Dockrell
- Department of Infection, Immunity, and Cardiovascular Disease, University of Sheffield Medical School, S10 2JF Sheffield, U.K
| | - Simon J Foster
- The Florey Institute, University of Sheffield, S10 2TN Sheffield, U.K
- Department of Molecular Biology and Biotechnology, University of Sheffield, S10 2TN Sheffield, U.K
| | - Timothy D McHugh
- Department of Clinical Microbiology, University College London, Royal Free Hospital, NW3 2PF London, U.K
| | - Stephen A Renshaw
- The Bateson Centre, University of Sheffield, Firth Court, S10 2TN Sheffield, U.K
- Department of Infection, Immunity, and Cardiovascular Disease, University of Sheffield Medical School, S10 2JF Sheffield, U.K
- The Florey Institute, University of Sheffield, S10 2TN Sheffield, U.K
| | - Josep Samitier Martí
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Department of Electronics and Biomedical Engineering, University of Barcelona, 08028 Barcelona, Spain
- Networking Biomedical Research Center for Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
| | - Giuseppe Battaglia
- Department of Chemistry, University College London, WC1H 0AJ London, U.K
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- The EPSRC/Jeol Centre for Liquid Phase Electron Microscopy, University College London, WC1H 0AJ London, U.K
- Institute for Physics of Living System, University College London, WC1E 6BT London, U.K
- Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
| | - Loris Rizzello
- Department of Chemistry, University College London, WC1H 0AJ London, U.K
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Department of Pharmaceutical Sciences, University of Milan, 20133 Milano, Italy
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5
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Preston JA, Bewley MA, Marriott HM, McGarry Houghton A, Mohasin M, Jubrail J, Morris L, Stephenson YL, Cross S, Greaves DR, Craig RW, van Rooijen N, Bingle CD, Read RC, Mitchell TJ, Whyte MKB, Shapiro SD, Dockrell DH. Alveolar Macrophage Apoptosis-associated Bacterial Killing Helps Prevent Murine Pneumonia. Am J Respir Crit Care Med 2020; 200:84-97. [PMID: 30649895 DOI: 10.1164/rccm.201804-0646oc] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Rationale: Antimicrobial resistance challenges therapy of pneumonia. Enhancing macrophage microbicidal responses would combat this problem but is limited by our understanding of how alveolar macrophages (AMs) kill bacteria. Objectives: To define the role and mechanism of AM apoptosis-associated bacterial killing in the lung. Methods: We generated a unique CD68.hMcl-1 transgenic mouse with macrophage-specific overexpression of the human antiapoptotic Mcl-1 protein, a factor upregulated in AMs from patients at increased risk of community-acquired pneumonia, to address the requirement for apoptosis-associated killing. Measurements and Main Results: Wild-type and transgenic macrophages demonstrated comparable ingestion and initial phagolysosomal killing of bacteria. Continued ingestion (for ≥12 h) overwhelmed initial killing, and a second, late-phase microbicidal response killed viable bacteria in wild-type macrophages, but this response was blunted in CD68.hMcl-1 transgenic macrophages. The late phase of bacterial killing required both caspase-induced generation of mitochondrial reactive oxygen species and nitric oxide, the peak generation of which coincided with the late phase of killing. The CD68.hMcl-1 transgene prevented mitochondrial reactive oxygen species but not nitric oxide generation. Apoptosis-associated killing enhanced pulmonary clearance of Streptococcus pneumoniae and Haemophilus influenzae in wild-type mice but not CD68.hMcl-1 transgenic mice. Bacterial clearance was enhanced in vivo in CD68.hMcl-1 transgenic mice by reconstitution of apoptosis with BH3 mimetics or clodronate-encapsulated liposomes. Apoptosis-associated killing was not activated during Staphylococcus aureus lung infection. Conclusions: Mcl-1 upregulation prevents macrophage apoptosis-associated killing and establishes that apoptosis-associated killing is required to allow AMs to clear ingested bacteria. Engagement of macrophage apoptosis should be investigated as a novel, host-based antimicrobial strategy.
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Affiliation(s)
- Julie A Preston
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Martin A Bewley
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Helen M Marriott
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - A McGarry Houghton
- 3 Clinical Research Division, Fred Hutchinson Cancer Research Center, and.,4 Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, Washington
| | - Mohammed Mohasin
- 5 Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | | | - Lucy Morris
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Yvonne L Stephenson
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Simon Cross
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom.,7 Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - David R Greaves
- 8 Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Ruth W Craig
- 9 Department of Pharmacology and Toxicology, Geissel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Nico van Rooijen
- 10 Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, the Netherlands
| | - Colin D Bingle
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Robert C Read
- 11 University of Southampton Medical School, Southampton, United Kingdom.,12 National Institute for Health Research Southampton Biomedical Research Centre, Southampton, United Kingdom
| | - Timothy J Mitchell
- 13 Institute of Microbiology and Infection, School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom; and
| | - Moira K B Whyte
- 6 MRC Centre for Inflammation Research.,14 Department of Respiratory Medicine, and
| | - Steven D Shapiro
- 15 Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - David H Dockrell
- 6 MRC Centre for Inflammation Research.,16 Infection Medicine, University of Edinburgh, Edinburgh, United Kingdom
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6
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Collini PJ, Bewley MA, Mohasin M, Marriott HM, Miller RF, Geretti AM, Beloukas A, Papadimitropoulos A, Read RC, Noursadeghi M, Dockrell DH. HIV gp120 in the Lungs of Antiretroviral Therapy-treated Individuals Impairs Alveolar Macrophage Responses to Pneumococci. Am J Respir Crit Care Med 2019; 197:1604-1615. [PMID: 29365279 DOI: 10.1164/rccm.201708-1755oc] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
RATIONALE People living with HIV are at significantly increased risk of invasive pneumococcal disease, despite long-term antiretroviral therapy (ART). The mechanism explaining this observation remains undefined. OBJECTIVES To determine if apoptosis-associated microbicidal mechanisms, required to clear intracellular pneumococci that survive initial phagolysosomal killing, are perturbed. METHODS Alveolar macrophages (AM) were obtained by BAL from healthy donors or HIV-1-seropositive donors on long-term ART with undetectable plasma viral load. Monocyte-derived macrophages (MDM) were obtained from healthy donors and infected with HIV-1BaL or treated with gp120. Macrophages were challenged with opsonized serotype 2 Streptococcus pneumoniae and assessed for apoptosis, bactericidal activity, protein expression, and mitochondrial reactive oxygen species (mROS). AM phenotyping, ultrasensitive HIV-1 RNA quantification, and gp120 measurement were also performed in BAL. MEASUREMENTS AND MAIN RESULTS HIV-1BaL infection impaired apoptosis, induction of mROS, and pneumococcal killing by MDM. Apoptosis-associated pneumococcal killing was also reduced in AM from ART-treated HIV-1-seropositive donors. BAL fluid from these individuals demonstrated persistent lung CD8+ T lymphocytosis, and gp120 or HIV-1 RNA was also detected. Despite this, transcriptional activity in AM freshly isolated from people living with HIV was broadly similar to healthy volunteers. Instead, gp120 phenocopied the defect in pneumococcal killing in healthy MDM through post-translational modification of Mcl-1, preventing apoptosis induction, caspase activation, and increased mROS generation. Moreover, gp120 also inhibited mROS-dependent pneumococcal killing in MDM. CONCLUSIONS Despite ART, HIV-1, via gp120, drives persisting innate immune defects in AM microbicidal mechanisms, enhancing susceptibility to pneumococcal disease.
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Affiliation(s)
- Paul J Collini
- 1 The Florey Institute for Host-Pathogen Interactions and Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom.,2 Academic Directorate of Communicable Diseases and Specialised Medicine, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
| | - Martin A Bewley
- 1 The Florey Institute for Host-Pathogen Interactions and Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Mohamed Mohasin
- 1 The Florey Institute for Host-Pathogen Interactions and Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Helen M Marriott
- 1 The Florey Institute for Host-Pathogen Interactions and Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Robert F Miller
- 3 Research Department of Infection and Population Health, Institute of Epidemiology & Health Care, Faculty of Population Health Sciences, and
| | - Anna-Maria Geretti
- 4 Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Apostolos Beloukas
- 4 Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Athanasios Papadimitropoulos
- 4 Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Robert C Read
- 5 Academic Unit of Clinical and Experimental Sciences, University of Southampton and National Institute for Health Research Southampton Biomedical Research Centre, Southampton, United Kingdom; and
| | - Mahdad Noursadeghi
- 6 Division of Infection & Immunity, Faculty of Medical Sciences, University College London, London, United Kingdom
| | - David H Dockrell
- 1 The Florey Institute for Host-Pathogen Interactions and Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom.,2 Academic Directorate of Communicable Diseases and Specialised Medicine, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom.,7 MRC/UoE Centre for Inflammation Research, The University of Edinburgh, Edinburgh, United Kingdom
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7
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Hughes BM, Burton CS, Reese A, Jabeen MF, Wright C, Willis J, Khoshaein N, Marsh EK, Peachell P, Sun SC, Dockrell DH, Marriott HM, Sabroe I, Condliffe AM, Prince LR. Pellino-1 Regulates Immune Responses to Haemophilus influenzae in Models of Inflammatory Lung Disease. Front Immunol 2019; 10:1721. [PMID: 31417543 PMCID: PMC6685348 DOI: 10.3389/fimmu.2019.01721] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [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: 03/13/2019] [Accepted: 07/09/2019] [Indexed: 11/24/2022] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) is a frequent cause of lower respiratory tract infection in people with chronic obstructive pulmonary disease (COPD). Pellino proteins are a family of E3 ubiquitin ligases that are critical regulators of TLR signaling and inflammation. The aim of this study was to identify a role for Pellino-1 in airway defense against NTHi in the context of COPD. Pellino-1 is rapidly upregulated by LPS and NTHi in monocyte-derived macrophages (MDMs) isolated from individuals with COPD and healthy control subjects, in a TLR4 dependent manner. C57BL/6 Peli1−/− and wild-type (WT) mice were subjected to acute (single LPS challenge) or chronic (repeated LPS and elastase challenge) airway inflammation followed by NTHi infection. Both WT and Peli1−/− mice develop airway inflammation in acute and chronic airway inflammation models. Peli1−/− animals recruit significantly more neutrophils to the airway following NTHi infection which is associated with an increase in the neutrophil chemokine, KC, in bronchoalveolar lavage fluid as well as enhanced clearance of NTHi from the lung. These data suggest that therapeutic inhibition of Pellino-1 may augment immune responses in the airway and enhance bacterial clearance in individuals with COPD.
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Affiliation(s)
- Bethany M Hughes
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Charlotte S Burton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Abigail Reese
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Maisha F Jabeen
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Carl Wright
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Jessica Willis
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Nika Khoshaein
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Elizabeth K Marsh
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Peter Peachell
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Shao C Sun
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - David H Dockrell
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom.,MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Helen M Marriott
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Ian Sabroe
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Alison M Condliffe
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Lynne R Prince
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
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8
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Abstract
The tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a widely expressed cytokine that can bind five different receptors. TRAIL has been of particular interest for its proposed ability to selectively induce apoptosis in tumour cells. However, it has also been found to regulate a wide variety of non-canonical cellular effects including survival, migration and proliferation via kinase signalling pathways. Lung diseases represent a wide range of conditions affecting multiple tissues. TRAIL has been implicated in several biological processes underlying lung diseases, including angiogenesis, inflammation, and immune regulation. For example, TRAIL is detrimental in pulmonary arterial hypertension—it is upregulated in patient serum and lungs, and drives the underlying proliferative pulmonary vascular remodelling in rodent models. However, TRAIL protects against pulmonary fibrosis in mice models—by inducing apoptosis of neutrophils—and reduced serum TRAIL is found in patients. Conversely, in the airways TRAIL positively regulates inflammation and immune response. In COPD patients and asthmatic patients challenged with antigen, TRAIL and its death receptors are upregulated in serum and airways. Furthermore, TRAIL-deleted mouse models have reduced airway inflammation and remodelling. In the context of respiratory infections, TRAIL assists in immune response, e.g., via T-cell toxicity in influenza infection, and neutrophil killing in S. pneumoniae infection. In this mini-review, we examine the functions of TRAIL and highlight the diverse roles TRAIL has in diseases affecting the lung. Disentangling the facets of TRAIL signalling in lung diseases could help in understanding their pathogenic processes and targeting novel treatments.
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Affiliation(s)
- Adam T Braithwaite
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Medical School, Sheffield, United Kingdom
| | - Helen M Marriott
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Medical School, Sheffield, United Kingdom
| | - Allan Lawrie
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Medical School, Sheffield, United Kingdom
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9
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Bewley MA, Preston JA, Mohasin M, Marriott HM, Budd RC, Swales J, Collini P, Greaves DR, Craig RW, Brightling CE, Donnelly LE, Barnes PJ, Singh D, Shapiro SD, Whyte MKB, Dockrell DH. Impaired Mitochondrial Microbicidal Responses in Chronic Obstructive Pulmonary Disease Macrophages. Am J Respir Crit Care Med 2017; 196:845-855. [PMID: 28557543 DOI: 10.1164/rccm.201608-1714oc] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
RATIONALE Chronic obstructive pulmonary disease (COPD) is characterized by impaired clearance of pulmonary bacteria. OBJECTIVES The effect of COPD on alveolar macrophage (AM) microbicidal responses was investigated. METHODS AMs were obtained from bronchoalveolar lavage from healthy donors or patients with COPD and challenged with opsonized serotype 14 Streptococcus pneumoniae. Cells were assessed for apoptosis, bactericidal activity, and mitochondrial reactive oxygen species (mROS) production. A transgenic mouse line in which the CD68 promoter ensures macrophage-specific expression of human induced myeloid leukemia cell differentiation protein Mcl-1 (CD68.hMcl-1) was used to model the molecular aspects of COPD. MEASUREMENTS AND MAIN RESULTS COPD AMs had elevated levels of Mcl-1, an antiapoptotic B-cell lymphoma 2 family member, with selective reduction of delayed intracellular bacterial killing. CD68.hMcl-1 AMs phenocopied the microbicidal defect because transgenic mice demonstrated impaired clearance of pulmonary bacteria and increased neutrophilic inflammation. Murine bone marrow-derived macrophages and human monocyte-derived macrophages generated mROS in response to pneumococci, which colocalized with bacteria and phagolysosomes to enhance bacterial killing. The Mcl-1 transgene increased oxygen consumption rates and mROS expression in mock-infected bone marrow-derived macrophages but reduced caspase-dependent mROS production after pneumococcal challenge. COPD AMs also increased basal mROS expression, but they failed to increase production after pneumococcal challenge, in keeping with reduced intracellular bacterial killing. The defect in COPD AM intracellular killing was associated with a reduced ratio of mROS/superoxide dismutase 2. CONCLUSIONS Up-regulation of Mcl-1 and chronic adaption to oxidative stress alter mitochondrial metabolism and microbicidal function, reducing the delayed phase of intracellular bacterial clearance in COPD.
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Affiliation(s)
- Martin A Bewley
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Julie A Preston
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Mohammed Mohasin
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Helen M Marriott
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Richard C Budd
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom.,3 Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
| | - Julie Swales
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Paul Collini
- 1 The Florey Institute for Host-Pathogen Interactions and.,2 Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, United Kingdom.,3 Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
| | - David R Greaves
- 4 Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Ruth W Craig
- 5 Department of Pharmacology and Toxicology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | | | - Louise E Donnelly
- 7 Airway Disease National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Peter J Barnes
- 7 Airway Disease National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Dave Singh
- 8 Centre for Respiratory and Allergy, University of Manchester, Manchester, United Kingdom.,9 Medicines Evaluation Unit, Manchester, United Kingdom.,10 University Hospital of South Manchester NHS Foundation Trust, Manchester, United Kingdom
| | - Steven D Shapiro
- 11 Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; and
| | - Moira K B Whyte
- 12 Department of Respiratory Medicine.,13 MRC Centre for Inflammation Research, and
| | - David H Dockrell
- 13 MRC Centre for Inflammation Research, and.,14 Department of Infection Medicine, University of Edinburgh, Edinburgh, United Kingdom
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10
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Sadiku P, Willson JA, Dickinson RS, Murphy F, Harris AJ, Lewis A, Sammut D, Mirchandani AS, Ryan E, Watts ER, Thompson AR, Marriott HM, Dockrell DH, Taylor CT, Schneider M, Maxwell PH, Chilvers ER, Mazzone M, Moral V, Pugh CW, Ratcliffe PJ, Schofield CJ, Ghesquiere B, Carmeliet P, Whyte MK, Walmsley SR. Prolyl hydroxylase 2 inactivation enhances glycogen storage and promotes excessive neutrophilic responses. J Clin Invest 2017; 127:3407-3420. [PMID: 28805660 PMCID: PMC5669581 DOI: 10.1172/jci90848] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [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: 09/21/2016] [Accepted: 06/29/2017] [Indexed: 12/30/2022] Open
Abstract
Fully activated innate immune cells are required for effective responses to infection, but their prompt deactivation and removal are essential for limiting tissue damage. Here, we have identified a critical role for the prolyl hydroxylase enzyme Phd2 in maintaining the balance between appropriate, predominantly neutrophil-mediated pathogen clearance and resolution of the innate immune response. We demonstrate that myeloid-specific loss of Phd2 resulted in an exaggerated inflammatory response to Streptococcus pneumonia, with increases in neutrophil motility, functional capacity, and survival. These enhanced neutrophil responses were dependent upon increases in glycolytic flux and glycogen stores. Systemic administration of a HIF-prolyl hydroxylase inhibitor replicated the Phd2-deficient phenotype of delayed inflammation resolution. Together, these data identify Phd2 as the dominant HIF-hydroxylase in neutrophils under normoxic conditions and link intrinsic regulation of glycolysis and glycogen stores to the resolution of neutrophil-mediated inflammatory responses. These results demonstrate the therapeutic potential of targeting metabolic pathways in the treatment of inflammatory disease.
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Affiliation(s)
- Pranvera Sadiku
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Laboratory of Angiogenesis and Vascular Metabolism, Vesalius Research Center, Leuven, Belgium
| | - Joseph A. Willson
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Rebecca S. Dickinson
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Fiona Murphy
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Alison J. Harris
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Amy Lewis
- Academic Unit of Respiratory Medicine and
| | | | - Ananda S. Mirchandani
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Eilise Ryan
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Emily R. Watts
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Helen M. Marriott
- Academic Unit of Immunology and Infectious Diseases, Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - David H. Dockrell
- Academic Unit of Immunology and Infectious Diseases, Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Cormac T. Taylor
- UCD School of Medicine and Medical Science, Conway Institute, University College Dublin, Dublin, Ireland
| | - Martin Schneider
- General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Patrick H. Maxwell
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Edwin R. Chilvers
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Massimilliano Mazzone
- Laboratory of Tumour Inflammation and Angiogenesis, Department of Oncology, Leuven, Belgium
| | - Veronica Moral
- Laboratory of Angiogenesis and Vascular Metabolism, Vesalius Research Center, Leuven, Belgium
| | | | | | | | - Bart Ghesquiere
- Laboratory of Angiogenesis and Vascular Metabolism, Vesalius Research Center, Leuven, Belgium
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Vascular Metabolism, Vesalius Research Center, Leuven, Belgium
| | - Moira K.B. Whyte
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Sarah R. Walmsley
- MRC/University of Edinburgh Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
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11
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Dickinson RS, Thompson AAR, Thomson JP, Murphy F, Marriott HM, Tavares A, Willson J, Williams L, Lewis A, Forbes S, Stimson RH, Hameed AG, Preston JA, Lawrie A, Finisguerra V, Mazzone M, Foster SJ, Chilvers ER, Cowburn AS, Dockrell DH, Johnson RS, Meehan RR, Whyte MKB, Walmsley SR. S104 Hypoxia preconditions the innate immune response to acute bacterial pulmonary infections. Thorax 2016. [DOI: 10.1136/thoraxjnl-2016-209333.110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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12
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Gill SK, Marriott HM, Suvarna SK, Peachell PT. Evaluation of the anti-inflammatory effects of β-adrenoceptor agonists on human lung macrophages. Eur J Pharmacol 2016; 793:49-55. [PMID: 27832943 DOI: 10.1016/j.ejphar.2016.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [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: 06/07/2016] [Revised: 10/31/2016] [Accepted: 11/02/2016] [Indexed: 12/21/2022]
Abstract
The principal mechanism by which bronchodilator β-adrenoceptor agonists act is to relax airways smooth muscle although they may also be anti-inflammatory. However, the extent of anti-inflammatory activity and the cell types affected by these agonists are uncertain. The purpose of this study was to evaluate whether β-adrenoceptor agonists prevent pro-inflammatory cytokine generation from activated human lung macrophages. Macrophages were isolated and purified from human lung. The cells were pre-treated with both short-acting (isoprenaline, salbutamol, terbutaline) and long-acting (formoterol, salmeterol, indacaterol) β-agonists before activation with lipopolysaccharide (LPS) to induce cytokine (TNFα, IL-6, IL-8 and IL-10) generation. The experiments showed that short-acting β-agonists were poor inhibitors of cytokine generation. Of the long-acting β-agonists studied, formoterol was also a weak inhibitor of cytokine generation whereas only indacaterol and salmeterol showed moderate inhibitory activity. Further experiments using the β2-adrenoceptor antagonist ICI-118,551 suggested that the effects of indacaterol were likely to be mediated by β2-adrenoceptors whereas those of salmeterol were not. These findings were corroborated by functional desensitization studies in which the inhibitory effects of indacaterol appeared to be receptor-mediated whereas those of salmeterol were not. Taken together, the data indicate that the anti-inflammatory effects of β-adrenoceptor agonists on human lung macrophages are modest.
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Affiliation(s)
- Sharonjit K Gill
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, The Medical School (Floor L), Beech Hill Road, Sheffield S10 2RX, UK
| | - Helen M Marriott
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, The Medical School (Floor L), Beech Hill Road, Sheffield S10 2RX, UK
| | - S Kim Suvarna
- Histopathology Department, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK
| | - Peter T Peachell
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, The Medical School (Floor L), Beech Hill Road, Sheffield S10 2RX, UK.
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13
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Gill SK, Yao Y, Kay LJ, Bewley MA, Marriott HM, Peachell PT. The anti-inflammatory effects of PGE 2 on human lung macrophages are mediated by the EP 4 receptor. Br J Pharmacol 2016; 173:3099-3109. [PMID: 27460634 DOI: 10.1111/bph.13565] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/19/2016] [Accepted: 07/19/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE PGE2 inhibits cytokine generation from human lung macrophages. However, the EP receptor that mediates this beneficial anti-inflammatory effect of PGE2 has not been defined. The aim of this study was to identify the EP receptor by which PGE2 inhibits cytokine generation from human lung macrophages. This was determined by using recently developed EP receptor ligands. EXPERIMENTAL APPROACH The effects of PGE2 and EP-selective agonists on LPS-induced generation of TNF-α and IL-6 from macrophages were evaluated. The effects of EP2 -selective (PF-04852946, PF-04418948) and EP4 -selective (L-161,982, CJ-042794) receptor antagonists on PGE2 responses were studied. The expression of EP receptor subtypes by human lung macrophages was determined by RT-PCR. KEY RESULTS PGE2 inhibited LPS-induced and Streptococcus pneumoniae-induced cytokine generation from human lung macrophages. Analysis of mRNA levels indicated that macrophages expressed EP2 and EP4 receptors. L-902,688 (EP4 receptor-selective agonist) was considerably more potent than butaprost (EP2 receptor-selective agonist) as an inhibitor of TNF-α generation from macrophages. EP2 receptor-selective antagonists had marginal effects on the PGE2 inhibition of TNF-α generation, whereas EP4 receptor-selective antagonists caused rightward shifts in the PGE2 concentration-response curves. CONCLUSIONS AND IMPLICATIONS These studies demonstrate that the EP4 receptor is the principal receptor that mediates the anti-inflammatory effects of PGE2 on human lung macrophages. This suggests that EP4 receptor agonists could be effective anti-inflammatory agents in human lung disease.
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Affiliation(s)
- Sharonjit K Gill
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, The Medical School (Floor L), University of Sheffield, Sheffield, UK
| | - Yiwen Yao
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, The Medical School (Floor L), University of Sheffield, Sheffield, UK
| | - Linda J Kay
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, The Medical School (Floor L), University of Sheffield, Sheffield, UK
| | - Martin A Bewley
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, The Medical School (Floor L), University of Sheffield, Sheffield, UK
| | - Helen M Marriott
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, The Medical School (Floor L), University of Sheffield, Sheffield, UK
| | - Peter T Peachell
- Academic Unit of Respiratory Medicine, Department of Infection, Immunity and Cardiovascular Disease, The Medical School (Floor L), University of Sheffield, Sheffield, UK.
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14
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Jubrail J, Morris P, Bewley MA, Stoneham S, Johnston SA, Foster SJ, Peden AA, Read RC, Marriott HM, Dockrell DH. Inability to sustain intraphagolysosomal killing of Staphylococcus aureus predisposes to bacterial persistence in macrophages. Cell Microbiol 2015; 18:80-96. [PMID: 26248337 PMCID: PMC4778410 DOI: 10.1111/cmi.12485] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [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: 06/12/2015] [Accepted: 07/07/2015] [Indexed: 12/25/2022]
Abstract
Macrophages are critical effectors of the early innate response to bacteria in tissues. Phagocytosis and killing of bacteria are interrelated functions essential for bacterial clearance but the rate-limiting step when macrophages are challenged with large numbers of the major medical pathogen Staphylococcus aureus is unknown. We show that macrophages have a finite capacity for intracellular killing and fail to match sustained phagocytosis with sustained microbial killing when exposed to large inocula of S. aureus (Newman, SH1000 and USA300 strains). S. aureus ingestion by macrophages is associated with a rapid decline in bacterial viability immediately after phagocytosis. However, not all bacteria are killed in the phagolysosome, and we demonstrate reduced acidification of the phagolysosome, associated with failure of phagolysosomal maturation and reduced activation of cathepsin D. This results in accumulation of viable intracellular bacteria in macrophages. We show macrophages fail to engage apoptosis-associated bacterial killing. Ultittop mately macrophages with viable bacteria undergo cell lysis, and viable bacteria are released and can be internalized by other macrophages. We show that cycles of lysis and reuptake maintain a pool of viable intracellular bacteria over time when killing is overwhelmed and demonstrate intracellular persistence in alveolar macrophages in the lungs in a murine model.
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Affiliation(s)
- Jamil Jubrail
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Paul Morris
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Martin A Bewley
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Simon Stoneham
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - Simon A Johnston
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK.,Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Simon J Foster
- The Florey Institute, University of Sheffield, Sheffield, UK.,Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Andrew A Peden
- Department of Biomedical Sciences, University of Sheffield, Sheffield, UK
| | - Robert C Read
- Academic Unit of Clinical and Experimental Sciences, University of Southampton Medical School, Southampton, UK
| | - Helen M Marriott
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK
| | - David H Dockrell
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.,The Florey Institute, University of Sheffield, Sheffield, UK.,Academic Directorate of Communicable Diseases, Sheffield Teaching Hospitals, Sheffield, UK
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15
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Masca NGD, Hensor EMA, Cornelius VR, Buffa FM, Marriott HM, Eales JM, Messenger MP, Anderson AE, Boot C, Bunce C, Goldin RD, Harris J, Hinchliffe RF, Junaid H, Kingston S, Martin-Ruiz C, Nelson CP, Peacock J, Seed PT, Shinkins B, Staples KJ, Toombs J, Wright AKA, Teare MD. RIPOSTE: a framework for improving the design and analysis of laboratory-based research. eLife 2015; 4:e05519. [PMID: 25951517 PMCID: PMC4461852 DOI: 10.7554/elife.05519] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [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: 11/07/2014] [Accepted: 05/01/2015] [Indexed: 12/17/2022] Open
Abstract
Lack of reproducibility is an ongoing problem in some areas of the biomedical sciences. Poor experimental design and a failure to engage with experienced statisticians at key stages in the design and analysis of experiments are two factors that contribute to this problem. The RIPOSTE (Reducing IrreProducibility in labOratory STudiEs) framework has been developed to support early and regular discussions between scientists and statisticians in order to improve the design, conduct and analysis of laboratory studies and, therefore, to reduce irreproducibility. This framework is intended for use during the early stages of a research project, when specific questions or hypotheses are proposed. The essential points within the framework are explained and illustrated using three examples (a medical equipment test, a macrophage study and a gene expression study). Sound study design minimises the possibility of bias being introduced into experiments and leads to higher quality research with more reproducible results.
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Affiliation(s)
- Nicholas GD Masca
- Cardiovascular Biomedical Research Unit, University of Leicester, Leicester, United Kingdom
| | - Elizabeth MA Hensor
- Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, United Kingdom; Leeds Institute of Rheumatic and Musculoskeletal Medicine, NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, United Kingdom
| | - Victoria R Cornelius
- Department of Primary Care and Public Health Sciences, King's College London, London, United Kingdom
| | - Francesca M Buffa
- Applied Computational Genomics, University of Oxford, Oxford, United Kingdom
| | - Helen M Marriott
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom; The Florey Institute, University of Sheffield, Sheffield, United Kingdom
| | - James M Eales
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Michael P Messenger
- NIHR Diagnostic Evidence Co-Operative Leeds, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | - Amy E Anderson
- Musculoskeletal Research Group, Institute of Cellular Medicine, University of Newcastle, Newcastle, United Kingdom
| | - Chris Boot
- Newcastle Hospitals NHS Trust, Newcastle, United Kingdom
| | - Catey Bunce
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom; London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Robert D Goldin
- Centre for Pathology, Imperial College, London, United Kingdom
| | - Jessica Harris
- Clinical Trials and Evaluation Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Rod F Hinchliffe
- Department of Paediatric Haematology, Sheffield Children's NHS Foundation Trust, Sheffield, United Kingdom
| | - Hiba Junaid
- Royal London Hospital, London, United Kingdom
| | - Shaun Kingston
- Respiratory Biomedical Research Unit, Royal Brompton and Harefield NHS Trust, London, United Kingdom
| | - Carmen Martin-Ruiz
- Institute for Ageing and Health, Newcastle University, Newcastle, United Kingdom
| | - Christopher P Nelson
- Department of Cardiovascular Sciences, NIHR Leicester Cardiovascular Biomedical Research Unit, University of Leicester, Leicester, United Kingdom
| | - Janet Peacock
- Division of Health and Social Care Research, Kings College London, London, United Kingdom; NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation, London, United Kingdom
| | - Paul T Seed
- Division of Women's Health, King's College London, London, United Kingdom
| | - Bethany Shinkins
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
| | - Karl J Staples
- Clinical and Experimental Sciences, University of Southampton and NIHR Southampton Respiratory Biomedical Research Unit, Southampton General Hospital, Southampton, United Kingdom
| | - Jamie Toombs
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, United Kingdom
| | - Adam KA Wright
- Institute of Lung Health, Respiratory Biomedical Unit, University Hospitals of Leicester NHS Trust, Leicester, United Kingdom
| | - M Dawn Teare
- Sheffield School of Health and Related Research, University of Sheffield, Sheffield, United Kingdom
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16
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Aberdein JD, Cole J, Bewley MA, Marriott HM, Dockrell DH. Alveolar macrophages in pulmonary host defence the unrecognized role of apoptosis as a mechanism of intracellular bacterial killing. Clin Exp Immunol 2013; 174:193-202. [PMID: 23841514 DOI: 10.1111/cei.12170] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2013] [Indexed: 01/12/2023] Open
Abstract
Alveolar macrophages play an essential role in clearing bacteria from the lower airway, as the resident phagocyte alveolar macrophages must both phagocytose and kill bacteria, and if unable to do this completely must co-ordinate an inflammatory response. The decision to escalate the inflammatory response represents the transition between subclinical infection and the development of pneumonia. Alveolar macrophages are well equipped to phagocytose bacteria and have a large phagolysosomal capacity in which ingested bacteria are killed. The rate-limiting step in control of extracellular bacteria, such as Streptococcus pneumoniae, is the capacity of alveolar macrophages to kill ingested bacteria. Therefore, alveolar macrophages complement canonical microbicidal strategies with an additional level of apoptosis-associated killing to help kill ingested bacteria.
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Affiliation(s)
- J D Aberdein
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, UK
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17
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Bingle CD, Araujo B, Wallace WA, Marriott HM, Hirani N, Bingle L. P140 BPIFB1/LPLUNC1 is a novel marker for the bronchiolised epithelium in IPF. Thorax 2013. [DOI: 10.1136/thoraxjnl-2013-204457.290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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18
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Thompson AAR, Marriott HM, Williams L, Shaw G, Hameed A, Parmar S, Preston JA, Simon MC, Johnson RS, Foster SJ, Dockrell DH, Whyte MK, Walmsley SR. P143 Hypoxia induces hypothermia and sickness behaviour in mice following subcutaneous injection of live Staphylococcus aureus. Thorax 2013. [DOI: 10.1136/thoraxjnl-2013-204457.293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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19
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Bazaz R, Marriott HM, Francis SE, Dockrell DH. Mechanistic links between acute respiratory tract infections and acute coronary syndromes. J Infect 2013; 66:1-17. [DOI: 10.1016/j.jinf.2012.09.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 09/22/2012] [Accepted: 09/26/2012] [Indexed: 12/27/2022]
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Thompson AAR, Elks PM, Marriott HM, Higgins KR, Parmar S, Shaw G, Eamsamarng S, McGrath EE, Formenti F, Eeden FJV, Kinnula VL, Pugh CW, Sabroe I, Dockrell DH, Chilvers ER, Robbins PA, Simon MC, Johnson RS, Renshaw SA, Whyte MKB, Walmsley SR. T1 Hypoxia-Inducible Factor 2α Regulates Neutrophilic Inflammation in Humans, Mice and Zebrafish. Thorax 2012. [DOI: 10.1136/thoraxjnl-2012-202678.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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21
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Musa M, Wilson K, Sun L, Mulay A, Bingle L, Marriott HM, LeClair EE, Bingle CD. Differential localisation of BPIFA1 (SPLUNC1) and BPIFB1 (LPLUNC1) in the nasal and oral cavities of mice. Cell Tissue Res 2012; 350:455-64. [PMID: 22986921 PMCID: PMC3505551 DOI: 10.1007/s00441-012-1490-9] [Citation(s) in RCA: 27] [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: 05/10/2012] [Accepted: 08/16/2012] [Indexed: 01/14/2023]
Abstract
Despite being initially identified in mice, little is known about the sites of production of members of the BPI fold (BPIF) containing (PLUNC) family of putative innate defence proteins in this species. These proteins have largely been considered to be specificaly expressed in the respiratory tract, and we have recently shown that they exhibit differential expression in the epithelium of the proximal airways. In this study, we have used species-specific antibodies to systematically localize two members of this protein family; BPIFA1 (PLUNC/SPLUNC1) and BPIFB1 (LPLUNC1) in adult mice. In general, these proteins exhibit distinct and only partially overlapping localization. BPIFA1 is highly expressed in the respiratory epithelium and Bowman’s glands of the nasal passages, whereas BPIFB1 is present in small subset of goblet cells in the nasal passage and pharynx. BPIFB1 is also present in the serous glands in the proximal tongue where is co-localised with the salivary gland specific family member, BPIFA2E (parotid secretory protein) and also in glands of the soft palate. Both proteins exhibit limited expression outside of these regions. These results are consistent with the localization of the proteins seen in man. Knowledge of the complex expression patterns of BPIF proteins in these regions will allow the use of tractable mouse models of disease to dissect their function.
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Affiliation(s)
- Maslinda Musa
- Academic Unit of Respiratory Medicine, Department of Infection and Immunity, University of Sheffield, UK
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22
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Daigneault M, De Silva TI, Bewley MA, Preston JA, Marriott HM, Mitchell AM, Mitchell TJ, Read RC, Whyte MKB, Dockrell DH. Monocytes regulate the mechanism of T-cell death by inducing Fas-mediated apoptosis during bacterial infection. PLoS Pathog 2012; 8:e1002814. [PMID: 22829769 PMCID: PMC3400568 DOI: 10.1371/journal.ppat.1002814] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [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: 12/16/2011] [Accepted: 06/04/2012] [Indexed: 12/24/2022] Open
Abstract
Monocytes and T-cells are critical to the host response to acute bacterial infection but monocytes are primarily viewed as amplifying the inflammatory signal. The mechanisms of cell death regulating T-cell numbers at sites of infection are incompletely characterized. T-cell death in cultures of peripheral blood mononuclear cells (PBMC) showed 'classic' features of apoptosis following exposure to pneumococci. Conversely, purified CD3(+) T-cells cultured with pneumococci demonstrated necrosis with membrane permeabilization. The death of purified CD3(+) T-cells was not inhibited by necrostatin, but required the bacterial toxin pneumolysin. Apoptosis of CD3(+) T-cells in PBMC cultures required 'classical' CD14(+) monocytes, which enhanced T-cell activation. CD3(+) T-cell death was enhanced in HIV-seropositive individuals. Monocyte-mediated CD3(+) T-cell apoptotic death was Fas-dependent both in vitro and in vivo. In the early stages of the T-cell dependent host response to pneumococci reduced Fas ligand mediated T-cell apoptosis was associated with decreased bacterial clearance in the lung and increased bacteremia. In summary monocytes converted pathogen-associated necrosis into Fas-dependent apoptosis and regulated levels of activated T-cells at sites of acute bacterial infection. These changes were associated with enhanced bacterial clearance in the lung and reduced levels of invasive pneumococcal disease.
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Affiliation(s)
- Marc Daigneault
- Department of Infection and Immunity, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Thushan I. De Silva
- Department of Infection and Immunity, University of Sheffield Medical School, Sheffield, United Kingdom
- Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - Martin A. Bewley
- Department of Infection and Immunity, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Julie A. Preston
- Department of Infection and Immunity, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Helen M. Marriott
- Department of Infection and Immunity, University of Sheffield Medical School, Sheffield, United Kingdom
| | - Andrea M. Mitchell
- Institute of Microbiology and Infection, School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Timothy J. Mitchell
- Institute of Microbiology and Infection, School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Robert C. Read
- Department of Infection and Immunity, University of Sheffield Medical School, Sheffield, United Kingdom
- Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - Moira K. B. Whyte
- Department of Infection and Immunity, University of Sheffield Medical School, Sheffield, United Kingdom
- Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - David H. Dockrell
- Department of Infection and Immunity, University of Sheffield Medical School, Sheffield, United Kingdom
- Sheffield Teaching Hospitals, Sheffield, United Kingdom
- * E-mail:
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23
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Marriott HM, Daigneault M, Thompson AAR, Walmsley SR, Gill SK, Witcher DR, Wroblewski VJ, Hellewell PG, Whyte MKB, Dockrell DH. A decoy receptor 3 analogue reduces localised defects in phagocyte function in pneumococcal pneumonia. Thorax 2012; 67:985-92. [PMID: 22735687 PMCID: PMC3505869 DOI: 10.1136/thoraxjnl-2012-201591] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [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: 11/23/2022]
Abstract
Background Therapeutic strategies to modulate the host response to bacterial pneumonia are needed to improve outcomes during community-acquired pneumonia. This study used mice with impaired Fas signalling to examine susceptibility to pneumococcal pneumonia and decoy receptor 3 analogue (DcR3-a) to correct factors associated with increased susceptibility. Methods Wild-type mice and those with varying degrees of impairment of Fas (lpr) or Fas ligand signalling (gld) were challenged with Streptococcus pneumoniae and microbiological and immunological outcomes measured in the presence or absence of DcR3-a. Results During established pneumonia, neutrophils became the predominant cell in the airway and gld mice were less able to clear bacteria from the lungs, demonstrating localised impairment of pulmonary neutrophil function in comparison to lpr or wild-type mice. T-cells from gld mice had enhanced activation and reduced apoptosis in comparison to wild-type and lpr mice during established pneumonia. Treatment with DcR3-a reduced T-cell activation and corrected the defect in pulmonary bacterial clearance in gld mice. Conclusions The results suggest that imbalance in tumour necrosis factor superfamily signalling and excessive T-cell activation can impair bacterial clearance in the lung but that DcR3-a treatment can reduce T-cell activation, restore optimal pulmonary neutrophil function and enhance bacterial clearance during S pneumoniae infection.
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Affiliation(s)
- Helen M Marriott
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK.
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24
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McGrath EE, Lawrie A, Marriott HM, Mercer P, Cross SS, Arnold N, Singleton V, Thompson AAR, Walmsley SR, Renshaw SA, Sabroe I, Chambers RC, Dockrell DH, Whyte MKB. Deficiency of tumour necrosis factor-related apoptosis-inducing ligand exacerbates lung injury and fibrosis. Thorax 2012; 67:796-803. [PMID: 22496351 PMCID: PMC3426075 DOI: 10.1136/thoraxjnl-2011-200863] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND The death receptor ligand tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) shows considerable clinical promise as a therapeutic agent. TRAIL induces leukocyte apoptosis, reducing acute inflammatory responses in the lung. It is not known whether TRAIL modifies chronic lung injury or whether TRAIL has a role in human idiopathic pulmonary fibrosis (IPF). We therefore explored the capacity of TRAIL to modify chronic inflammatory lung injury and studied TRAIL expression in patients with IPF. METHODS TRAIL(-/-) and wild-type mice were instilled with bleomycin and inflammation assessed at various time points by bronchoalveolar lavage and histology. Collagen deposition was measured by tissue hydroxyproline content. TRAIL expression in human IPF lung samples was assessed by immunohistochemistry and peripheral blood TRAIL measured by ELISA. RESULTS TRAIL(-/-) mice had an exaggerated delayed inflammatory response to bleomycin, with increased neutrophil numbers (mean 3.19±0.8 wild type vs 11.5±5.4×10(4) TRAIL(-/-), p<0.0001), reduced neutrophil apoptosis (5.42±1.6% wild type vs 2.47±0.5% TRAIL(-/-), p=0.0003) and increased collagen (3.45±0.2 wild type vs 5.8±1.3 mg TRAIL(-/-), p=0.005). Immunohistochemical analysis showed induction of TRAIL in bleomycin-treated wild-type mice. Patients with IPF demonstrated lower levels of TRAIL expression than in control lung biopsies and their serum levels of TRAIL were significantly lower compared with matched controls (38.1±9.6 controls vs 32.3±7.2 pg/ml patients with IPF, p=0.002). CONCLUSION These data suggest TRAIL may exert beneficial, anti-inflammatory actions in chronic pulmonary inflammation in murine models and that these mechanisms may be compromised in human IPF.
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Affiliation(s)
- Emmet E McGrath
- Department of Infection and Immunity, University of Sheffield, Sheffield, UK
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25
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Bewley MA, Pham TK, Marriott HM, Noirel J, Chu HP, Ow SY, Ryazanov AG, Read RC, Whyte MKB, Chain B, Wright PC, Dockrell DH. Proteomic evaluation and validation of cathepsin D regulated proteins in macrophages exposed to Streptococcus pneumoniae. Mol Cell Proteomics 2011; 10:M111.008193. [PMID: 21474794 PMCID: PMC3108842 DOI: 10.1074/mcp.m111.008193] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [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: 01/26/2011] [Revised: 04/01/2011] [Indexed: 11/23/2022] Open
Abstract
Macrophages are central effectors of innate immune responses to bacteria. We have investigated how activation of the abundant macrophage lysosomal protease, cathepsin D, regulates the macrophage proteome during killing of Streptococcus pneumoniae. Using the cathepsin D inhibitor pepstatin A, we demonstrate that cathepsin D differentially regulates multiple targets out of 679 proteins identified and quantified by eight-plex isobaric tag for relative and absolute quantitation. Our statistical analysis identified 18 differentially expressed proteins that passed all paired t-tests (α = 0.05). This dataset was enriched for proteins regulating the mitochondrial pathway of apoptosis or inhibiting competing death programs. Five proteins were selected for further analysis. Western blotting, followed by pharmacological inhibition or genetic manipulation of cathepsin D, verified cathepsin D-dependent regulation of these proteins, after exposure to S. pneumoniae. Superoxide dismutase-2 up-regulation was temporally related to increased reactive oxygen species generation. Gelsolin, a known regulator of mitochondrial outer membrane permeabilization, was down-regulated in association with cytochrome c release from mitochondria. Eukaryotic elongation factor (eEF2), a regulator of protein translation, was also down-regulated by cathepsin D. Using absence of the negative regulator of eEF2, eEF2 kinase, we confirm that eEF2 function is required to maintain expression of the anti-apoptotic protein Mcl-1, delaying macrophage apoptosis and confirm using a murine model that maintaining eEF2 function is associated with impaired macrophage apoptosis-associated killing of Streptococcus pneumoniae. These findings demonstrate that cathepsin D regulates multiple proteins controlling the mitochondrial pathway of macrophage apoptosis or competing death processes, facilitating intracellular bacterial killing.
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Affiliation(s)
| | - Trong K. Pham
- §ChELSI Institute, Department of Chemical and Processing Engineering, University of Sheffield, Sheffield, UK
| | | | - Josselin Noirel
- §ChELSI Institute, Department of Chemical and Processing Engineering, University of Sheffield, Sheffield, UK
| | - Hseuh-Ping Chu
- ‖Department of Pharmacology University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Jersey, USA
| | - Saw Y. Ow
- §ChELSI Institute, Department of Chemical and Processing Engineering, University of Sheffield, Sheffield, UK
| | - Alexey G. Ryazanov
- ‖Department of Pharmacology University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Jersey, USA
| | - Robert C. Read
- From the ‡Medical School
- ‡‡Sheffield Teaching Hospitals and
| | | | - Benny Chain
- ¶Division of Infection and Immunity, University College London, London, UK
| | - Phillip C. Wright
- §ChELSI Institute, Department of Chemical and Processing Engineering, University of Sheffield, Sheffield, UK
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McGrath EE, Marriott HM, Lawrie A, Francis SE, Sabroe I, Renshaw SA, Dockrell DH, Whyte MKB. TNF-related apoptosis-inducing ligand (TRAIL) regulates inflammatory neutrophil apoptosis and enhances resolution of inflammation. J Leukoc Biol 2011; 90:855-65. [PMID: 21562052 PMCID: PMC3644175 DOI: 10.1189/jlb.0211062] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The death ligand TRAIL plays a role in physiologic resolution of inflammation and exogenous TRAIL has potential therapeutic benefits in neutrophil-dominant inflammation. Novel therapeutics targeting neutrophilic inflammation are a major unmet clinical need in acute and chronic inflammation. The timely induction of neutrophil apoptosis is critical for inflammation resolution, and it is thought that acceleration of apoptosis may facilitate resolution at inflammatory sites. We previously demonstrated that a death receptor ligand, TRAIL, accelerates neutrophil apoptosis in vitro. We examined the role of TRAIL in neutrophil-dominant inflammation in WT and TRAIL-deficient mice. TRAIL deficiency did not alter constitutive neutrophil apoptosis, whereas exogenous TRAIL accelerated apoptosis of murine peripheral blood neutrophils. We compared TRAIL-deficient and WT mice in two independent models of neutrophilic inflammation: bacterial LPS-induced acute lung injury and zymosan-induced peritonitis. In both models, TRAIL-deficient mice had an enhanced inflammatory response with increased neutrophil numbers and reduced neutrophil apoptosis. Correction of TRAIL deficiency and supraphysiological TRAIL signaling using exogenous protein enhanced neutrophil apoptosis and reduced neutrophil numbers in both inflammatory models with no evidence of effects on other cell types. These data indicate the potential therapeutic benefit of TRAIL in neutrophilic inflammation.
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Affiliation(s)
- Emmet E McGrath
- Academic Unit of Respiratory Medicine, Department of Infection and Immunity, University of Sheffield, Sheffield, UK
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27
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Walmsley SR, Chilvers ER, Thompson AA, Vaughan K, Marriott HM, Parker LC, Shaw G, Parmar S, Schneider M, Sabroe I, Dockrell DH, Milo M, Taylor CT, Johnson RS, Pugh CW, Ratcliffe PJ, Maxwell PH, Carmeliet P, Whyte MKB. Prolyl hydroxylase 3 (PHD3) is essential for hypoxic regulation of neutrophilic inflammation in humans and mice. J Clin Invest 2011; 121:1053-63. [PMID: 21317538 DOI: 10.1172/jci43273] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 12/15/2010] [Indexed: 11/17/2022] Open
Abstract
The regulation of neutrophil lifespan by induction of apoptosis is critical for maintaining an effective host response and preventing excessive inflammation. The hypoxia-inducible factor (HIF) oxygen-sensing pathway has a major effect on the susceptibility of neutrophils to apoptosis, with a marked delay in cell death observed under hypoxic conditions. HIF expression and transcriptional activity are regulated by the oxygen-sensitive prolyl hydroxylases (PHD1-3), but the role of PHDs in neutrophil survival is unclear. We examined PHD expression in human neutrophils and found that PHD3 was strongly induced in response to hypoxia and inflammatory stimuli in vitro and in vivo. Using neutrophils from mice deficient in Phd3, we demonstrated a unique role for Phd3 in prolonging neutrophil survival during hypoxia, distinct from other hypoxia-associated changes in neutrophil function and metabolic activity. Moreover, this selective defect in neutrophil survival occurred in the presence of preserved HIF transcriptional activity but was associated with upregulation of the proapoptotic mediator Siva1 and loss of its binding target Bcl-xL. In vivo, using an acute lung injury model, we observed increased levels of neutrophil apoptosis and clearance in Phd3-deficient mice compared with WT controls. We also observed reduced neutrophilic inflammation in an acute mouse model of colitis. These data support what we believe to be a novel function for PHD3 in regulating neutrophil survival in hypoxia and may enable the development of new therapeutics for inflammatory disease.
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Affiliation(s)
- Sarah R Walmsley
- Academic Unit of Respiratory Medicine, The Medical School, University of Sheffield, Sheffield, United Kingdom.
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28
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Bewley MA, Marriott HM, Tulone C, Francis SE, Mitchell TJ, Read RC, Chain B, Kroemer G, Whyte MKB, Dockrell DH. A cardinal role for cathepsin d in co-ordinating the host-mediated apoptosis of macrophages and killing of pneumococci. PLoS Pathog 2011; 7:e1001262. [PMID: 21298030 PMCID: PMC3029254 DOI: 10.1371/journal.ppat.1001262] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [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: 03/19/2010] [Accepted: 12/21/2010] [Indexed: 11/23/2022] Open
Abstract
The bactericidal function of macrophages against pneumococci is enhanced by their apoptotic demise, which is controlled by the anti-apoptotic protein Mcl-1. Here, we show that lysosomal membrane permeabilization (LMP) and cytosolic translocation of activated cathepsin D occur prior to activation of a mitochondrial pathway of macrophage apoptosis. Pharmacological inhibition or knockout of cathepsin D during pneumococcal infection blocked macrophage apoptosis. As a result of cathepsin D activation, Mcl-1 interacted with its ubiquitin ligase Mule and expression declined. Inhibition of cathepsin D had no effect on early bacterial killing but inhibited the late phase of apoptosis-associated killing of pneumococci in vitro. Mice bearing a cathepsin D−/− hematopoietic system demonstrated reduced macrophage apoptosis in vivo, with decreased clearance of pneumococci and enhanced recruitment of neutrophils to control pulmonary infection. These findings establish an unexpected role for a cathepsin D-mediated lysosomal pathway of apoptosis in pulmonary host defense and underscore the importance of apoptosis-associated microbial killing to macrophage function. Tissue macrophages frequently undergo a program of cell death, termed apoptosis, following sustained ingestion and killing of bacteria. In macrophages, induction of apoptosis enhances bacterial killing when macrophages' initial killing capacity is exhausted. We have investigated the mechanism of apoptosis in macrophages exposed to pneumococci, the commonest cause of bacterial pneumonia. We show that the cell structure containing ingested bacteria, the phagolysosome, becomes permeabilized early in the death process. Pneumococcal exposure activates a phagolysosomal enzyme, cathepsin D, which induces apoptosis. Cathepsin D activation is required for permeabilization of mitochondria, an organelle implicated in apoptosis induction. Cathepsin D reduces levels of a negative regulator of apoptosis in macrophages, Mcl-1, by enhancing its association with an enzyme, which mediates its degradation. The importance of these findings was confirmed in a bone marrow transplant model in which mice either received bone marrow from mice containing or lacking the cathepsin D gene. This model showed that reduced apoptosis of alveolar macrophages occurred when cathepsin D was lacking, and that this impaired clearance of pneumococci in the mouse lung. We conclude that during bacterial challenge, lysosomal permeabilization and cathepsin D activation triggers a novel death pathway, in a timely fashion, linking bacterial killing to apoptosis induction.
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Affiliation(s)
- Martin A Bewley
- Medical School, University of Sheffield, Sheffield, United Kingdom
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29
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Webster SJ, Daigneault M, Bewley MA, Preston JA, Marriott HM, Walmsley SR, Read RC, Whyte MKB, Dockrell DH. Distinct cell death programs in monocytes regulate innate responses following challenge with common causes of invasive bacterial disease. J Immunol 2010; 185:2968-79. [PMID: 20656927 DOI: 10.4049/jimmunol.1000805] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Peripheral blood monocytes represent the rapid response component of mononuclear phagocyte host defense, generating vigorous but finite antibacterial responses. We investigated the fate of highly purified primary human monocytes following phagocytosis of different bacteria. Exposure to high bacterial loads resulted in rapid loss of cell viability and decreased functional competence. Cell death typically involved classical apoptosis. Exposure to high numbers of Escherichia coli and Klebsiella pneumoniae induced nonapoptotic death with loss of cell membrane integrity, marked disruption of phagolysosomes, and caspase-1 activation, while a subset of cells also released caspase-1-regulated extracellular traps. Classical apoptosis increased if extracellular bacterial replication was reduced and decreased if intracellular ATP levels were reduced during these infections. Both classical apoptosis and the alternative forms of cell death allowed monocytes, whose functional competence was exhausted, to downregulate reactive oxygen species and proinflammatory cytokine responses. In contrast, sustained stimulation of glycolytic metabolism and mitochondrial oxidative phosphorylation, with associated hypoxia inducible factor-1alpha upregulation, maintained intracellular ATP levels and prolonged monocyte functional longevity, as assessed by maintenance of phagocytosis, reactive oxygen species production, and proinflammatory cytokine generation. Monocyte innate responses to bacteria are short-lived and are limited by an intrinsic program of apoptosis, a response that is subverted by overwhelming infection with E. coli and K. pneumoniae or bacterial stimulation of cell metabolism. In this regard, the fate of monocytes following bacterial challenge more closely resembles neutrophils than macrophages.
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Affiliation(s)
- Steve J Webster
- Department of Infection and Immunity, Medical School, University of Sheffield, Sheffield, United Kingdom
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30
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Daigneault M, Preston JA, Marriott HM, Whyte MKB, Dockrell DH. The identification of markers of macrophage differentiation in PMA-stimulated THP-1 cells and monocyte-derived macrophages. PLoS One 2010; 5:e8668. [PMID: 20084270 PMCID: PMC2800192 DOI: 10.1371/journal.pone.0008668] [Citation(s) in RCA: 805] [Impact Index Per Article: 57.5] [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: 09/25/2009] [Accepted: 12/21/2009] [Indexed: 12/12/2022] Open
Abstract
Differentiated macrophages are the resident tissue phagocytes and sentinel cells of the innate immune response. The phenotype of mature tissue macrophages represents the composite of environmental and differentiation-dependent imprinting. Phorbol-12-myristate-13-acetate (PMA) and 1,25-dihydroxyvitamin D3 (VD3) are stimuli commonly used to induce macrophage differentiation in monocytic cell lines but the extent of differentiation in comparison to primary tissue macrophages is unclear. We have compared the phenotype of the promonocytic THP-1 cell line after various protocols of differentiation utilising VD3 and PMA in comparison to primary human monocytes or monocyte-derived macrophages (MDM). Both stimuli induced changes in cell morphology indicative of differentiation but neither showed differentiation comparable to MDM. In contrast, PMA treatment followed by 5 days resting in culture without PMA (PMAr) increased cytoplasmic to nuclear ratio, increased mitochondrial and lysosomal numbers and altered differentiation-dependent cell surface markers in a pattern similar to MDM. Moreover, PMAr cells showed relative resistance to apoptotic stimuli and maintained levels of the differentiation-dependent anti-apoptotic protein Mcl-1 similar to MDM. PMAr cells retained a high phagocytic capacity for latex beads, and expressed a cytokine profile that resembled MDM in response to TLR ligands, in particular with marked TLR2 responses. Moreover, both MDM and PMAr retained marked plasticity to stimulus-directed polarization. These findings suggest a modified PMA differentiation protocol can enhance macrophage differentiation of THP-1 cells and identify increased numbers of mitochondria and lysosomes, resistance to apoptosis and the potency of TLR2 responses as important discriminators of the level of macrophage differentiation for transformed cells.
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Affiliation(s)
- Marc Daigneault
- Department of Infection and Immunity, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Julie A. Preston
- Department of Infection and Immunity, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Helen M. Marriott
- Department of Infection and Immunity, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Moira K. B. Whyte
- Department of Infection and Immunity, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - David H. Dockrell
- Department of Infection and Immunity, Medical School, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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31
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Abstract
The cholesterol-dependent cytolysins are pore-forming toxins. Pneumolysin is the cytolysin produced by Streptococcus pneumoniae and is a key virulence factor. The protein contains 471 amino acids and four structural domains. Binding to cholesterol is followed by oligomerization and membrane pore formation. Pneumolysin also activates the classical pathway of complement. Mutational analysis of the toxin and knowledge of sequence variation in outbreak strains suggests that additional activities of biologic importance exist. Pneumolysin activates a large number of genes, some by epigenetic modification, in eukaryotic cells and multiple signal transduction pathways. Cytolytic effects contribute to lung injury and neuronal damage while pro-inflammatory effects compound tissue damage. Nevertheless pneumolysin is a focal point of the immune response to pneumococci. Toll-like receptor 4-mediated recognition, osmosensing and T-cell responses to pneumolysin have been identified. In some animal models mutants that lack pneumolysin are associated with impaired bacterial clearance. Pneumolysin, which itself may induce apoptosis in neurones and other cells can activate host-mediated apoptosis in macrophages enhancing clearance. Disease pathogenesis, which has traditionally focused on the harmful effects of the toxin, increasingly recognises that a precarious balance between limited host responses to pneumolysin and either excessive immune responses or toxin-mediated subversion of host immunity exists.
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Affiliation(s)
- Helen M Marriott
- Section of Infection, Inflammation and Immunity, University of Sheffield School of Medicine and Biomedical Sciences, Sheffield, UK
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32
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Prince LR, Bianchi SM, Vaughan KM, Bewley MA, Marriott HM, Walmsley SR, Taylor GW, Buttle DJ, Sabroe I, Dockrell DH, Whyte MKB. Subversion of a lysosomal pathway regulating neutrophil apoptosis by a major bacterial toxin, pyocyanin. J Immunol 2008; 180:3502-11. [PMID: 18292577 DOI: 10.4049/jimmunol.180.5.3502] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Neutrophils undergo rapid constitutive apoptosis that is accelerated following bacterial ingestion as part of effective immunity, but is also accelerated by bacterial exotoxins as a mechanism of immune evasion. The paradigm of pathogen-driven neutrophil apoptosis is exemplified by the Pseudomonas aeruginosa toxic metabolite, pyocyanin. We previously showed pyocyanin dramatically accelerates neutrophil apoptosis both in vitro and in vivo, impairs host defenses, and favors bacterial persistence. In this study, we investigated the mechanisms of pyocyanin-induced neutrophil apoptosis. Pyocyanin induced early lysosomal dysfunction, shown by altered lysosomal pH, within 15 min of exposure. Lysosomal disruption was followed by mitochondrial membrane permeabilization, caspase activation, and destabilization of Mcl-1. Pharmacological inhibitors of a lysosomal protease, cathepsin D (CTSD), abrogated pyocyanin-induced apoptosis, and translocation of CTSD to the cytosol followed pyocyanin treatment and lysosomal disruption. A stable analog of cAMP (dibutyryl cAMP) impeded the translocation of CTSD and prevented the destabilization of Mcl-1 by pyocyanin. Thus, pyocyanin activated a coordinated series of events dependent upon lysosomal dysfunction and protease release, the first description of a bacterial toxin using a lysosomal cell death pathway. This may be a pathological pathway of cell death to which neutrophils are particularly susceptible, and could be therapeutically targeted to limit neutrophil death and preserve host responses.
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Affiliation(s)
- Lynne R Prince
- Academic Unit of Respiratory Medicine, University of Sheffield, Sheffield, UK
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33
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Abstract
Respiratory infections are a major cause of human morbidity and a leading cause of death. The lower respiratory tract is a sterile environment and host defense is well developed to clear bacteria. This response includes both humeral factors and resident and recruited cells. The alveolar macrophage is an integral component and its long-lifespan aids function. Following low-dose challenge alveolar macrophages clear bacteria from the lung, employing an over-lapping set of microbicidal strategies. At a higher-dose the phagocytic capacity of alveolar macrophages is overwhelmed but alveolar macrophages help orchestrate the inflammatory response. In the resolution phase of infection alveolar macrophages contribute to apoptosis induction and clearance of recruited cells. This process down-regulates pro-inflammatory cytokine production. Macrophage function is controlled by induction of apoptosis. Delayed-onset macrophage apoptosis contributes both to bacterial clearance and to resolution of the inflammatory response. Mcl-1, an anti-apoptotic protein with a very short half-life, is a key regulator of macrophage survival and therefore of host responses to common bacterial pathogens in the lung. Studies involving Streptococcus pneumoniae and other respiratory bacteria are discussed to illustrate these points and ephasise that the timing of macrophage apoptosis is important in determining its overall effect on the host pathogen interaction.
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Affiliation(s)
- Helen M Marriott
- Section of Infection, Inflammation and Immunity, University of Sheffield School of Medicine and Biomedical Sciences, Sheffield, UK
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Marriott HM, Jackson LE, Wilkinson TS, Simpson AJ, Mitchell TJ, Buttle DJ, Cross SS, Ince PG, Hellewell PG, Whyte MKB, Dockrell DH. Reactive oxygen species regulate neutrophil recruitment and survival in pneumococcal pneumonia. Am J Respir Crit Care Med 2008; 177:887-95. [PMID: 18202350 DOI: 10.1164/rccm.200707-990oc] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
RATIONALE The role of NADPH oxidase activation in pneumonia is complex because reactive oxygen species contribute to both microbial killing and regulation of the acute pulmonary infiltrate. The relative importance of each role remains poorly defined in community-acquired pneumonia. OBJECTIVES We evaluated the contribution of NADPH oxidase-derived reactive oxygen species to the pathogenesis of pneumococcal pneumonia, addressing both the contribution to microbial killing and regulation of the inflammatory response. METHODS Mice deficient in the gp91(phox) component of the phagocyte NADPH oxidase were studied after pneumococcal challenge. MEASUREMENTS AND MAIN RESULTS gp91(phox)(-/-) mice demonstrated no defect in microbial clearance as compared with wild-type C57BL/6 mice. A significant increase in bacterial clearance from the lungs of gp91(phox)(-/-) mice was associated with increased numbers of neutrophils in the lung, lower rates of neutrophil apoptosis, and enhanced activation. Marked alterations in pulmonary cytokine/chemokine expression were also noted in the lungs of gp91(phox)(-/-) mice, characterized by elevated levels of tumor necrosis factor-alpha, KC, macrophage inflammatory protein-2, monocyte chemotactic protein-1, and IL-6. The greater numbers of neutrophils in gp91(phox)(-/-) mice were not associated with increased lung injury. Levels of neutrophil elastase in bronchoalveolar lavage were not decreased in gp91(phox)(-/-) mice. CONCLUSIONS During pneumococcal pneumonia, NADPH oxidase-derived reactive oxygen species are redundant for host defense but limit neutrophil recruitment and survival. Decreased NADPH oxidase-dependent reactive oxygen species production is well tolerated and improves disease outcome during pneumococcal pneumonia by removing neutrophils from the tight constraints of reactive oxygen species-mediated regulation.
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Affiliation(s)
- Helen M Marriott
- Section of Infection and Inflammation, School of Medicine and Biomedical Sciences, University of Sheffield, LU107, Royal Hallamshire Hospital, Glossop Road, Sheffield, S10 2JF, UK
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Vaughan KR, Stokes L, Prince LR, Marriott HM, Meis S, Kassack MU, Bingle CD, Sabroe I, Surprenant A, Whyte MKB. Inhibition of neutrophil apoptosis by ATP is mediated by the P2Y11 receptor. J Immunol 2007; 179:8544-53. [PMID: 18056402 PMCID: PMC2292245 DOI: 10.4049/jimmunol.179.12.8544] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [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] [Indexed: 01/17/2023]
Abstract
Neutrophils undergo rapid constitutive apoptosis that is delayed by a range of pathogen- and host-derived inflammatory mediators. We have investigated the ability of the nucleotide ATP, to which neutrophils are exposed both in the circulation and at sites of inflammation, to modulate the lifespan of human neutrophils. We found that physiologically relevant concentrations of ATP cause a concentration-dependent delay of neutrophil apoptosis (assessed by morphology, annexin V/To-Pro3 staining, and mitochondrial membrane permeabilization). We found that even brief exposure to ATP (10 min) was sufficient to cause a long-lasting delay of apoptosis and showed that the effects were not mediated by ATP breakdown to adenosine. The P2 receptor mediating the antiapoptotic actions of ATP was identified using a combination of more selective ATP analogs, receptor expression studies, and study of downstream signaling pathways. Neutrophils were shown to express the P2Y11 receptor and inhibition of P2Y11 signaling using the antagonist NF157 abrogated the ATP-mediated delay of neutrophil apoptosis, as did inhibition of type I cAMP-dependent protein kinases activated downstream of P2Y11, without effects on constitutive apoptosis. Specific targeting of P2Y11 could retain key immune functions of neutrophils but reduce the injurious effects of increased neutrophil longevity during inflammation.
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Affiliation(s)
- Kathryn R Vaughan
- Academic Unit of Respiratory Medicine, School of Medicine and Biomedical Sciences, University of Sheffield, UK
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Bianchi SM, Prince LR, McPhillips K, Allen L, Marriott HM, Taylor GW, Hellewell PG, Sabroe I, Dockrell DH, Henson PW, Whyte MKB. Impairment of apoptotic cell engulfment by pyocyanin, a toxic metabolite of Pseudomonas aeruginosa. Am J Respir Crit Care Med 2007; 177:35-43. [PMID: 17916805 DOI: 10.1164/rccm.200612-1804oc] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Cystic fibrosis lung disease is characterized by accumulation of apoptotic neutrophils, indicating impaired clearance of dying cells. Pseudomonas aeruginosa, the principal microbial pathogen in cystic fibrosis, manipulates apoptosis induction via production of toxic metabolites. Whether these metabolites, particularly pyocyanin, can also modulate apoptotic cell engulfment is unknown. OBJECTIVES To assess the effects of pyocyanin on apoptotic cell engulfment by macrophages in vitro and in vivo and to investigate potential mechanisms of the observed effects. METHODS Human monocyte-derived macrophages were treated with pyocyanin before challenge with apoptotic neutrophils, apoptotic Jurkat cells, or latex beads, and phagocytosis was assessed by light microscopy and flow cytometry. Effects of pyocyanin production on apoptotic cell clearance in vivo were assessed in a murine model, comparing infection by wild-type or pyocyanin-deficient P. aeruginosa. Oxidant production was investigated using fluorescent probes and pharmacologic inhibition and Rho GTPase signaling by immunoblotting and inhibitor studies. MEASUREMENTS AND MAIN RESULTS Pyocyanin treatment impaired macrophage engulfment of apoptotic cells in vitro, without inducing significant macrophage apoptosis, whereas latex bead uptake was preserved. Macrophage ingestion of apoptotic cells was reduced and late apoptotic/necrotic cells were increased in mice infected with pyocyanin-producing P. aeruginosa compared with the pyocyanin-deficient strain. Inhibition of apoptotic cell uptake involved intracellular generation of reactive oxygen species (ROS) and effects on Rho GTPase signaling. Antioxidants or blockade of Rho signaling substantially restored apoptotic cell engulfment. CONCLUSIONS These studies demonstrate that P. aeruginosa can manipulate the inflammatory microenvironment through inhibition of apoptotic cell engulfment, and suggest potential strategies to limit pulmonary inflammation in cystic fibrosis.
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Affiliation(s)
- Stephen M Bianchi
- Academic Unit of Respiratory Medicine, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S10 2JF, UK
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Marriott HM, Hellewell PG, Cross SS, Ince PG, Whyte MKB, Dockrell DH. Decreased Alveolar Macrophage Apoptosis Is Associated with Increased Pulmonary Inflammation in a Murine Model of Pneumococcal Pneumonia. J Immunol 2006; 177:6480-8. [PMID: 17056580 PMCID: PMC7611733 DOI: 10.4049/jimmunol.177.9.6480] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Regulation of the inflammatory infiltrate is critical to the successful outcome of pneumonia. Alveolar macrophage apoptosis is a feature of pneumococcal infection and aids disease resolution. The host benefits of macrophage apoptosis during the innate response to bacterial infection are incompletely defined. Because NO is required for optimal macrophage apoptosis during pneumococcal infection, we have explored the role of macrophage apoptosis in regulating inflammatory responses during pneumococcal pneumonia, using inducible NO synthase (iNOS)-deficient mice. iNOS(-/-) mice demonstrated decreased numbers of apoptotic macrophages as compared with wild-type C57BL/6 mice following pneumococcal challenge, greater recruitment of neutrophils to the lung and enhanced expression of TNF-alpha. Pharmacologic inhibition of iNOS produced similar results. Greater pulmonary inflammation was associated with greater levels of early bacteremia, IL-6 production, lung inflammation, and mortality within the first 48 h in iNOS(-/-) mice. Labeled apoptotic alveolar macrophages were phagocytosed by resident macrophages in the lung and intratracheal instillation of exogenous apoptotic macrophages decreased neutrophil recruitment in iNOS(-/-) mice and decreased TNF-alpha mRNA in lungs and protein in bronchial alveolar lavage, as well as chemokines and cytokines including IL-6. These changes were associated with a lower probability of mice becoming bacteremic. This demonstrates the potential of apoptotic macrophages to down-regulate the inflammatory response and for the first time in vivo demonstrates that clearance of apoptotic macrophages decreases neutrophil recruitment and invasive bacterial disease during pneumonia.
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Affiliation(s)
| | | | | | | | | | - David H. Dockrell
- Corresponding Author: David H. Dockrell, Division of Genomic Medicine, F-Floor, University of Sheffield, Beech Hill Road, Sheffield. S10 2RX, UK. Phone: +44 114 2724072 Fax: +44 114 2713892
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Marriott HM, Hellewell PG, Whyte MKB, Dockrell DH. Contrasting roles for reactive oxygen species and nitric oxide in the innate response to pulmonary infection with Streptococcus pneumoniae. Vaccine 2006; 25:2485-90. [PMID: 17030496 PMCID: PMC7611732 DOI: 10.1016/j.vaccine.2006.09.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pulmonary innate response to low-dose bacterial challenge requires functioning alveolar macrophages (AM) but also subsequent macrophage apoptosis. To address the role of reactive oxygen species (ROS) and nitric oxide (NO) in AM apoptosis, sub-clinical Streptococcus pneumoniae infection was established in gp91(phox-/-) and inducible NO synthase deficient (iNOS(-/-)) mice. Both AM apoptosis and the number of macrophages containing apoptotic bodies are reduced in iNOS(-/-) as compared to control or gp91(phox-/-) mice. iNOS(-/-) mice recruit neutrophils and generate TNF-alpha to compensate for impaired AM competence but ROS deficiency has no apparent effect on AM function in this model.
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Affiliation(s)
- Helen M. Marriott
- Divisions of Genomic Medicine School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, UK
| | - Paul G. Hellewell
- Clinical Sciences North, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, UK
| | - Moira K. B. Whyte
- Divisions of Genomic Medicine School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, UK
| | - David H. Dockrell
- Divisions of Genomic Medicine School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, UK
- Corresponding Author: David H. Dockrell, Division of Genomic Medicine, F-Floor, University of Sheffield, Beech Hill Road, Sheffield. S10 2RX, UK. Phone: +44 114 2724072, Fax: +44 114 2713892,
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Marriott HM, Dockrell DH. Streptococcus pneumoniae: the role of apoptosis in host defense and pathogenesis. Int J Biochem Cell Biol 2006; 38:1848-54. [PMID: 16844403 DOI: 10.1016/j.biocel.2006.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 05/30/2006] [Accepted: 06/05/2006] [Indexed: 01/29/2023]
Abstract
Programmed cell death or apoptosis is a recognised feature of infection with Streptococcus pneumoniae, and is observed during pneumococcal meningitis and pneumonia. The cholesterol-dependent cytolysin, pneumolysin, is a major trigger of apoptosis in the brain in association with pneumococcal production of hydrogen peroxide. Pneumococcal cell wall is also an important stimulus for apoptosis. Microbial factors and host factors combine in causing apoptosis in the brain, with hippocampal neurons being particularly susceptible. In pulmonary infection epithelial cell apoptosis contributes to tissue injury but macrophage apoptosis may benefit the host, aiding microbial killing and downregulating the inflammatory response. During sepsis lymphocyte apoptosis may be harmful to the host while dendritic cell apoptosis may limit the generation of an adaptive immune response during infection. Apoptosis induction may be harmful or potentially beneficial during pneumococcal infection and understanding its function in each setting is essential to allow specific therapeutic intervention.
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Affiliation(s)
- Helen M Marriott
- Division of Genomic Medicine, F-Floor, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK
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Tunbridge AJ, Stevanin TM, Lee M, Marriott HM, Moir JWB, Read RC, Dockrell DH. Inhibition of macrophage apoptosis by Neisseria meningitidis requires nitric oxide detoxification mechanisms. Infect Immun 2006; 74:729-33. [PMID: 16369030 PMCID: PMC1346626 DOI: 10.1128/iai.74.1.729-733.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Host-driven macrophage apoptosis contributes to innate immunity during bacterial infection. Neisseria meningitidis inhibits apoptosis in a variety of cells, but its impact on macrophage apoptosis is unknown. We demonstrate that N. meningitidis prevents macrophage apoptosis via genes encoding nitric oxide detoxification and a porin, PorB.
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Affiliation(s)
- Anne J Tunbridge
- Division of Genomic Medicine, F-Floor, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, United Kingdom
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41
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Marriott HM, Bingle CD, Read RC, Braley KE, Kroemer G, Hellewell PG, Craig RW, Whyte MKB, Dockrell DH. Dynamic changes in Mcl-1 expression regulate macrophage viability or commitment to apoptosis during bacterial clearance. J Clin Invest 2005; 115:359-68. [PMID: 15650769 PMCID: PMC544034 DOI: 10.1172/jci21766] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2004] [Accepted: 11/30/2004] [Indexed: 02/03/2023] Open
Abstract
Macrophages are critical effectors of bacterial clearance and must retain viability, despite exposure to toxic bacterial products, until key antimicrobial functions are performed. Subsequently, host-mediated macrophage apoptosis aids resolution of infection. The ability of macrophages to make this transition from resistance to susceptibility to apoptosis is important for effective host innate immune responses. We investigated the role of Mcl-1, an essential regulator of macrophage lifespan, in this switch from viability to apoptosis, using the model of pneumococcal-associated macrophage apoptosis. Upon exposure to pneumococci, macrophages initially upregulate Mcl-1 protein and maintain viability for up to 14 hours. Subsequently, macrophages reduce expression of full-length Mcl-1 and upregulate a 34-kDa isoform of Mcl-1 corresponding to a novel BH3-only splice variant, Mcl-1(Exon-1). Change in expression of Mcl-1 protein is associated with mitochondrial membrane permeabilization, which is characterized by loss of mitochondrial inner transmembrane potential and translocation of cytochrome c and apoptosis-inducing factor. Following pneumococcal infection, macrophages expressing full-length human Mcl-1 as a transgene exhibit a delay in apoptosis and in bacterial killing. Mcl-1 transgenic mice clear pneumococci from the lung less efficiently than nontransgenic mice. Dynamic changes in Mcl-1 expression determine macrophage viability as well as antibacterial host defense.
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Affiliation(s)
- Helen M Marriott
- Division of Genomic Medicine, University of Sheffield, Sheffield, United Kingdom
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Marriott HM, Bingle CD, Read RC, Braley KE, Kroemer G, Hellewell PG, Craig RW, Whyte MK, Dockrell DH. Dynamic changes in Mcl-1 expression regulate macrophage viability or commitment to apoptosis during bacterial clearance. J Clin Invest 2005. [DOI: 10.1172/jci200521766] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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Marriott HM, Ali F, Read RC, Mitchell TJ, Whyte MKB, Dockrell DH. Nitric oxide levels regulate macrophage commitment to apoptosis or necrosis during pneumococcal infection. FASEB J 2004; 18:1126-8. [PMID: 15132983 DOI: 10.1096/fj.03-1450fje] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Macrophages are resistant to constitutive apoptosis, but infectious stimuli can induce either microbial or host-mediated macrophage apoptosis. Phagocytosis and killing of opsonized pneumococci by macrophages are potent stimuli for host-mediated apoptosis, but the link between pneumococcal killing and apoptosis induction remains undefined. We now show phagocytosis of pneumococci by differentiated human monocyte-derived macrophages (MDM) results in up-regulation of inducible nitric oxide synthase (iNOS) and increased production of NO and reactive nitrogen species. NO accumulation in macrophages initiates an apoptotic program that involves NO-dependent mitochondrial membrane permeabilization, Mcl-1 down-regulation, and caspase activation and results in nuclear condensation and fragmentation. An inhibitor of mitochondrial permeability transition, bongkrekic acid, decreases pneumococcal-associated macrophage apoptosis. Conversely, inhibition of NO production using iNOS inhibitors decreases bacterial killing and shifts the cell death program from apoptosis to necrosis. Pneumolysin contributes to both NO production and apoptosis induction. After initial microbial killing, NO accumulation switches the macrophage phenotype from an activated cell to a cell susceptible to apoptosis. These results illustrate important roles for NO in the integration of host defense and regulation of inflammation in human macrophages.
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Affiliation(s)
- Helen M Marriott
- Division of Genomic Medicine, University of Sheffield School of Medicine and Biomedical Sciences, Sheffield, UK
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Dockrell DH, Marriott HM, Prince LR, Ridger VC, Ince PG, Hellewell PG, Whyte MKB. Alveolar Macrophage Apoptosis Contributes to Pneumococcal Clearance in a Resolving Model of Pulmonary Infection. J Immunol 2003; 171:5380-8. [PMID: 14607941 DOI: 10.4049/jimmunol.171.10.5380] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The role of alveolar macrophages (AM) in host defense against pulmonary infection has been difficult to establish using in vivo models. This may reflect a reliance on models of fulminant infection. To establish a unique model of resolving infection, with which to address the function of AM, C57BL/6 mice received low-dose intratracheal administration of pneumococci. Administration of low doses of pneumococci produced a resolving model of pulmonary infection characterized by clearance of bacteria without features of pneumonia. AM depletion in this model significantly increased bacterial outgrowth in the lung. Interestingly, a significant increase in the number of apoptotic AM was noted with the low-dose infection as compared with mock infection. Caspase inhibition in this model decreased AM apoptosis and increased the number of bacteremic mice, indicating a novel role for caspase activation in pulmonary innate defense against pneumococci. These results suggest that AM play a key role in clearance of bacteria from the lung during subclinical infection and that induction of AM apoptosis contributes to the microbiologic host defense against pneumococci.
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MESH Headings
- Amino Acid Chloromethyl Ketones/administration & dosage
- Animals
- Apoptosis/immunology
- Bacteremia/enzymology
- Bacteremia/immunology
- Bacteremia/microbiology
- Caspase Inhibitors
- Cell Count
- Cysteine Proteinase Inhibitors/administration & dosage
- Disease Models, Animal
- Dose-Response Relationship, Immunologic
- Female
- Immunity, Innate
- Injections, Intraperitoneal
- Intubation, Intratracheal
- Macrophages, Alveolar/enzymology
- Macrophages, Alveolar/immunology
- Macrophages, Alveolar/microbiology
- Macrophages, Alveolar/pathology
- Mice
- Mice, Inbred C57BL
- Pneumonia, Pneumococcal/enzymology
- Pneumonia, Pneumococcal/immunology
- Pneumonia, Pneumococcal/microbiology
- Pneumonia, Pneumococcal/pathology
- Streptococcus pneumoniae/growth & development
- Streptococcus pneumoniae/immunology
- Up-Regulation/immunology
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Affiliation(s)
- David H Dockrell
- Division of Genomic Medicine, University of Sheffield School of Medicine and Biomedical Sciences, Sheffield, United Kingdom.
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Demoncheaux EAG, Higenbottam TW, Foster PJ, Borland CDR, Smith APL, Marriott HM, Bee D, Akamine S, Davies MB. Circulating nitrite anions are a directly acting vasodilator and are donors for nitric oxide. Clin Sci (Lond) 2002; 102:77-83. [PMID: 11749663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Inhaled nitric oxide (NO) is a pulmonary vasodilator, but also acts systemically, causing negative cardiac inotropic effects and a fall in systemic vascular resistance. Circulating metabolites of NO are presumed to be responsible. We questioned the role of nitrite anions and the manner in which they might contribute to these effects. Nitrite and nitrate anions coexist in blood, while circulating levels of dissolved NO are very low. Nitrate anions are not biologically active, but nitrite anions may have a biological role through the release of NO. In vitro, at 37 degrees C and in aerated Krebs bicarbonate solution, the steady-state concentration of dissolved NO was proportional to the concentration of NO in the gas. Nanomolar concentrations of dissolved NO coexisted with micromolar concentrations of nitrite anions. The idea of an equilibrium between the two in solution was also supported by the observed release of NO from nitrite anions in the absence of gas. With rings of precontracted pig pulmonary arteries (prostaglandin F(2alpha); 10 micromol/l), the steady-state concentration of dissolved NO causing 50% relaxation (EC(50)) was 0.84+/-0.25 nmol/l, corresponding to a gaseous concentration of 2.2 p.p.m. The EC(50) of nitrite was 4.5+/-0.7 micromol/l, a concentration normally found in plasma. The estimated concentration of dissolved NO derived from this nitrite was 4.5 pmol/l, some 100 times lower than would be needed to cause relaxation. The rate of exhalation of NO was increased and pulmonary vascular resistance was reduced by the addition of nitrite solution to the perfusate of isolated perfused and ventilated pig lungs, but only when millimolar concentrations were achieved. Thus circulating nitrite anions are a direct vasodilator, only being a carrier of effective amounts of "free" NO at higher than physiological concentrations.
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Affiliation(s)
- E A G Demoncheaux
- Academic Unit of Respiratory Medicine, Division of Clinical Sciences (South), Floor F, Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, U.K
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