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Allam C, Mouton W, Testaert H, Ginevra C, Fessy N, Ibranosyan M, Descours G, Beraud L, Guillemot J, Chapalain A, Albert-Vega C, Richard JC, Argaud L, Friggeri A, Labeye V, Jamilloux Y, Freymond N, Venet F, Lina G, Doublet P, Ader F, Trouillet-Assant S, Jarraud S. Hyper-inflammatory profile and immunoparalysis in patients with severe Legionnaires' disease. Front Cell Infect Microbiol 2023; 13:1252515. [PMID: 37965258 PMCID: PMC10641404 DOI: 10.3389/fcimb.2023.1252515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 09/28/2023] [Indexed: 11/16/2023] Open
Abstract
Introduction Severe Legionnaires' disease (LD) can lead to multi-organ failure or death in 10%-30% of patients. Although hyper-inflammation and immunoparalysis are well described in sepsis and are associated with high disease severity, little is known about the immune response in LD. This study aimed to evaluate the immune status of patients with LD and its association with disease severity. Methods A total of 92 hospitalized LD patients were included; 19 plasmatic cytokines and pulmonary Legionella DNA load were measured in 84 patients on the day of inclusion (day 0, D0). Immune functional assays (IFAs) were performed from whole blood samples collected at D2 and stimulated with concanavalin A [conA, n = 19 patients and n = 21 healthy volunteers (HV)] or lipopolysaccharide (LPS, n = 14 patients and n = 9 HV). A total of 19 cytokines (conA stimulation) and TNF-α (LPS stimulation) were quantified from the supernatants. The Sequential Organ Failure Assessment (SOFA) severity score was recorded at D0 and the mechanical ventilation (MV) status was recorded at D0 and D8. Results Among the 84 patients, a higher secretion of plasmatic MCP-1, MIP1-β, IL-6, IL-8, IFN-γ, TNF-α, and IL-17 was observed in the patients with D0 and D8 MV. Multiparametric analysis showed that these seven cytokines were positively associated with the SOFA score. Upon conA stimulation, LD patients had a lower secretion capacity for 16 of the 19 quantified cytokines and a higher release of IL-18 and MCP-1 compared to HV. IL-18 secretion was higher in D0 and D8 MV patients. TNF-α secretion, measured after ex vivo LPS stimulation, was significantly reduced in LD patients and was associated with D8 MV status. Discussion The present findings describe a hyper-inflammatory phase at the initial phase of Legionella pneumonia that is more pronounced in patients with severe LD. These patients also present an immunoparalysis for a large number of cytokines, except IL-18 whose secretion is increased. An assessment of the immune response may be relevant to identify patients eligible for future innovative host-directed therapies.
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Affiliation(s)
- Camille Allam
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - William Mouton
- Unité Mixte de Recherche Hospices Civils de Lyon-bioMérieux, Pierre-Bénite, France
- Centre International de Recherche en Infectiologie (CIRI), Virpath Team Inserm U1111, CNRS UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Hugo Testaert
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Christophe Ginevra
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Noémie Fessy
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Marine Ibranosyan
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Ghislaine Descours
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Laetitia Beraud
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Johann Guillemot
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Annelise Chapalain
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Chloé Albert-Vega
- Centre International de Recherche en Infectiologie (CIRI), Virpath Team Inserm U1111, CNRS UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Jean-Christophe Richard
- Service de Médecine Intensive-Réanimation - Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Laurent Argaud
- Service de Médecine Intensive-Réanimation - Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
| | - Arnaud Friggeri
- Département d’Anesthésie Réanimation - Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Pierre-Bénite, France
| | - Vanessa Labeye
- Service des urgences - Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Yvan Jamilloux
- Département de Médecine Interne, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Nathalie Freymond
- Service de Pneumologie, Centre Hospitalier Lyon Sud - Hospices Civils de Lyon, Pierre-Bénite, France
| | - Fabienne Venet
- Laboratoire d’Immunologie - Hôpital Edouard Herriot - Hospices Civils de Lyon, Lyon, France
- Centre International de Recherche en Infectiologie (CIRI), NLRP3 Inflammation and Immune Response to Sepsis, Inserm U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard-Lyon 1, Lyon, France
| | - Gérard Lina
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Patricia Doublet
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Florence Ader
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Département des Maladies Infectieuses et Tropicales - Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Sophie Trouillet-Assant
- Unité Mixte de Recherche Hospices Civils de Lyon-bioMérieux, Pierre-Bénite, France
- Centre International de Recherche en Infectiologie (CIRI), Virpath Team Inserm U1111, CNRS UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Sophie Jarraud
- Centre National de Référence des Légionelles, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
- Centre International de Recherche en Infectiologie (CIRI), Legiopath team, Inserm, U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
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Pollock TY, Vázquez Marrero VR, Brodsky IE, Shin S. TNF licenses macrophages to undergo rapid caspase-1, -11, and -8-mediated cell death that restricts Legionella pneumophila infection. PLoS Pathog 2023; 19:e1010767. [PMID: 37279255 DOI: 10.1371/journal.ppat.1010767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 05/25/2023] [Indexed: 06/08/2023] Open
Abstract
The inflammatory cytokine tumor necrosis factor (TNF) is necessary for host defense against many intracellular pathogens, including Legionella pneumophila. Legionella causes the severe pneumonia Legionnaires' disease and predominantly affects individuals with a suppressed immune system, including those receiving therapeutic TNF blockade to treat autoinflammatory disorders. TNF induces pro-inflammatory gene expression, cellular proliferation, and survival signals in certain contexts, but can also trigger programmed cell death in others. It remains unclear, however, which of the pleiotropic functions of TNF mediate control of intracellular bacterial pathogens like Legionella. In this study, we demonstrate that TNF signaling licenses macrophages to die rapidly in response to Legionella infection. We find that TNF-licensed cells undergo rapid gasdermin-dependent, pyroptotic death downstream of inflammasome activation. We also find that TNF signaling upregulates components of the inflammasome response, and that the caspase-11-mediated non-canonical inflammasome is the first inflammasome to be activated, with caspase-1 and caspase-8 mediating delayed pyroptotic death. We find that all three caspases are collectively required for optimal TNF-mediated restriction of bacterial replication in macrophages. Furthermore, caspase-8 is required for control of pulmonary Legionella infection. These findings reveal a TNF-dependent mechanism in macrophages for activating rapid cell death that is collectively mediated by caspases-1, -8, and -11 and subsequent restriction of Legionella infection.
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Affiliation(s)
- Tzvi Y Pollock
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Víctor R Vázquez Marrero
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Igor E Brodsky
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
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Chauhan D, Shames SR. Pathogenicity and Virulence of Legionella: Intracellular replication and host response. Virulence 2021; 12:1122-1144. [PMID: 33843434 PMCID: PMC8043192 DOI: 10.1080/21505594.2021.1903199] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bacteria of the genus Legionella are natural pathogens of amoebae that can cause a severe pneumonia in humans called Legionnaires’ Disease. Human disease results from inhalation of Legionella-contaminated aerosols and subsequent bacterial replication within alveolar macrophages. Legionella pathogenicity in humans has resulted from extensive co-evolution with diverse genera of amoebae. To replicate intracellularly, Legionella generates a replication-permissive compartment called the Legionella-containing vacuole (LCV) through the concerted action of hundreds of Dot/Icm-translocated effector proteins. In this review, we present a collective overview of Legionella pathogenicity including infection mechanisms, secretion systems, and translocated effector function. We also discuss innate and adaptive immune responses to L. pneumophila, the implications of Legionella genome diversity and future avenues for the field.
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Affiliation(s)
- Deepika Chauhan
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
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Viewing Legionella pneumophila Pathogenesis through an Immunological Lens. J Mol Biol 2019; 431:4321-4344. [PMID: 31351897 DOI: 10.1016/j.jmb.2019.07.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/25/2019] [Accepted: 07/13/2019] [Indexed: 12/14/2022]
Abstract
Legionella pneumophila is the causative agent of the severe pneumonia Legionnaires' disease. L. pneumophila is ubiquitously found in freshwater environments, where it replicates within free-living protozoa. Aerosolization of contaminated water supplies allows the bacteria to be inhaled into the human lung, where L. pneumophila can be phagocytosed by alveolar macrophages and replicate intracellularly. The Dot/Icm type IV secretion system (T4SS) is one of the key virulence factors required for intracellular bacterial replication and subsequent disease. The Dot/Icm apparatus translocates more than 300 effector proteins into the host cell cytosol. These effectors interfere with a variety of cellular processes, thus enabling the bacterium to evade phagosome-lysosome fusion and establish an endoplasmic reticulum-derived Legionella-containing vacuole, which facilitates bacterial replication. In turn, the immune system has evolved numerous strategies to recognize intracellular bacteria such as L. pneumophila, leading to potent inflammatory responses that aid in eliminating infection. This review aims to provide an overview of L. pneumophila pathogenesis in the context of the host immune response.
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Potentiation of Cytokine-Mediated Restriction of Legionella Intracellular Replication by a Dot/Icm-Translocated Effector. J Bacteriol 2019; 201:JB.00755-18. [PMID: 31036725 DOI: 10.1128/jb.00755-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/22/2019] [Indexed: 01/23/2023] Open
Abstract
Legionella pneumophila is ubiquitous in freshwater environments, where it replicates within unicellular protozoa. However, L. pneumophila is also an accidental human pathogen that can cause Legionnaires' disease in immunocompromised individuals by uncontrolled replication within alveolar macrophages. To replicate within eukaryotic phagocytes, L. pneumophila utilizes a Dot/Icm type IV secretion system to translocate a large arsenal of over 300 effector proteins directly into host cells. In mammals, translocated effectors contribute to innate immune restriction of L. pneumophila We found previously that the effector LegC4 is important for L. pneumophila replication within a natural host protist but is deleterious to replication in a mouse model of Legionnaires' disease. In the present study, we used cultured mouse primary macrophages to investigate how LegC4 attenuates L. pneumophila replication. We found that LegC4 enhanced restriction of L. pneumophila replication within macrophages activated with tumor necrosis factor (TNF) or interferon gamma (IFN-γ). In addition, expression of legC4 was sufficient to restrict Legionella longbeachae replication within TNF- or IFN-γ-activated macrophages. Thus, this study demonstrates that LegC4 contributes to L. pneumophila clearance from healthy hosts by potentiating cytokine-mediated host defense mechanisms.IMPORTANCE Legionella spp. are natural pathogens of protozoa and accidental pathogens of humans. Innate immunity in healthy individuals effectively controls Legionella infection due in part to rapid and robust production of proinflammatory cytokines resulting from detection of Dot/Icm-translocated substrates, including effectors. Here, we demonstrate that the effector LegC4 enhances proinflammatory host restriction of Legionella by macrophages. These data suggest that LegC4 may augment proinflammatory signaling or antimicrobial activity of macrophages, a function that has not previously been observed for another bacterial effector. Further insight into LegC4 function will likely reveal novel mechanisms to enhance immunity against pathogens.
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Ruiz-Moreno JS, Hamann L, Shah JA, Verbon A, Mockenhaupt FP, Puzianowska-Kuznicka M, Naujoks J, Sander LE, Witzenrath M, Cambier JC, Suttorp N, Schumann RR, Jin L, Hawn TR, Opitz B. The common HAQ STING variant impairs cGAS-dependent antibacterial responses and is associated with susceptibility to Legionnaires' disease in humans. PLoS Pathog 2018; 14:e1006829. [PMID: 29298342 PMCID: PMC5770077 DOI: 10.1371/journal.ppat.1006829] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 01/16/2018] [Accepted: 12/18/2017] [Indexed: 11/23/2022] Open
Abstract
The cyclic GMP-AMP synthase (cGAS)-STING pathway is central for innate immune sensing of various bacterial, viral and protozoal infections. Recent studies identified the common HAQ and R232H alleles of TMEM173/STING, but the functional consequences of these variants for primary infections are unknown. Here we demonstrate that cGAS- and STING-deficient murine macrophages as well as human cells of individuals carrying HAQ TMEM173/STING were severely impaired in producing type I IFNs and pro-inflammatory cytokines in response to Legionella pneumophila, bacterial DNA or cyclic dinucleotides (CDNs). In contrast, R232H attenuated cytokine production only following stimulation with bacterial CDN, but not in response to L. pneumophila or DNA. In a mouse model of Legionnaires’ disease, cGAS- and STING-deficient animals exhibited higher bacterial loads as compared to wild-type mice. Moreover, the haplotype frequency of HAQ TMEM173/STING, but not of R232H TMEM173/STING, was increased in two independent cohorts of human Legionnaires’ disease patients as compared to healthy controls. Our study reveals that the cGAS-STING cascade contributes to antibacterial defense against L. pneumophila in mice and men, and provides important insight into how the common HAQ TMEM173/STING variant affects antimicrobial immune responses and susceptibility to infection. Interferons (IFNs) and pro-inflammatory cytokines are key regulators of gene expression and antibacterial defense during Legionella pneumophila infection. Here we demonstrate that production of these mediators was largely or partly dependent on the cyclic GMP-AMP synthase (cGAS)-STING pathway in human and murine cells. Cells of individuals carrying the common HAQ allele of TMEM173/STING were strongly impaired in their ability to respond to L. pneumophila, bacterial DNA or cyclic dinucleotides (CDNs), whereas the R232H allele was only attenuated in sensing of exogenous CDNs. Importantly, cGAS and STING contributed to antibacterial defense in mice during L. pneumophila lung infection, and the allele frequency of HAQ TMEM173/STING, but not of R232H TMEM173/STING, was increased in two independent cohorts of human Legionnaires’ disease patients as compared to healthy controls. Hence, sensing of bacterial DNA by the cGAS/STING pathway contributes to antibacterial defense against L. pneumophila infection, and the hypomorphic variant HAQ TMEM173/STING is associated with increased susceptibility to Legionnaires’ disease in humans.
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Affiliation(s)
- Juan S. Ruiz-Moreno
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Lutz Hamann
- Institute of Microbiology and Hygiene, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health Berlin, Berlin, Germany
| | - Javeed A. Shah
- Department of Medicine, University of Washington, Seattle, Washington, United states of America
- VA Puget Sound Health Care System, Seattle, Washington, United states of America
| | - Annelies Verbon
- Department of Medical Microbiology and Infectious diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Frank P. Mockenhaupt
- Institute of Tropical Medicine and International Health, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Monika Puzianowska-Kuznicka
- Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
- Department of Geriatrics and Gerontology, Medical Centre of Postgraduate Education, Warsaw, Poland
| | - Jan Naujoks
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Leif E. Sander
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- German Center for Lung Research (DZL), Germany
| | - Martin Witzenrath
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- German Center for Lung Research (DZL), Germany
- CAPNETZ STIFTUNG, Hannover, Germany
| | - John C. Cambier
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Norbert Suttorp
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- German Center for Lung Research (DZL), Germany
- CAPNETZ STIFTUNG, Hannover, Germany
| | - Ralf R. Schumann
- Institute of Microbiology and Hygiene, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health Berlin, Berlin, Germany
| | - Lei Jin
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Thomas R. Hawn
- Department of Medicine, University of Washington, Seattle, Washington, United states of America
| | - Bastian Opitz
- Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- German Center for Lung Research (DZL), Germany
- * E-mail:
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Naujoks J, Lippmann J, Suttorp N, Opitz B. Innate sensing and cell-autonomous resistance pathways in Legionella pneumophila infection. Int J Med Microbiol 2017; 308:161-167. [PMID: 29097162 DOI: 10.1016/j.ijmm.2017.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 12/20/2022] Open
Abstract
Legionella pneumophila is a facultative intracellular bacterium which can cause a severe pneumonia called Legionnaires' disease after inhalation of contaminated water droplets and replication in alveolar macrophages. The innate immune system is generally able to sense and -in most cases- control L. pneumophila infection. Comorbidities and genetic risk factors, however, can compromise the immune system and high infection doses might overwhelm its capacity, thereby enabling L. pneumophila to grow and disseminate inside the lung. The innate immune system mediates sensing of L. pneumophila by employing e.g. NOD-like receptors (NLRs), Toll-like receptors (TLRs), as well as the cGAS/STING pathway to stimulate death of infected macrophages as well as production of proinflammatory cytokines and interferons (IFNs). Control of pulmonary L. pneumophila infection is largely mediated by inflammasome-, TNFα- and IFN-dependent macrophage-intrinsic resistance mechanisms. This article summarizes the current knowledge of innate immune responses to L. pneumophila infection in general, and of macrophage-intrinsic defense mechanisms in particular.
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Affiliation(s)
- Jan Naujoks
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Juliane Lippmann
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Norbert Suttorp
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Bastian Opitz
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Augustenburger Platz 1, 13353 Berlin, Germany; German Center for Lung Research (DZL), Germany.
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Neutrophil and Alveolar Macrophage-Mediated Innate Immune Control of Legionella pneumophila Lung Infection via TNF and ROS. PLoS Pathog 2016; 12:e1005591. [PMID: 27105352 PMCID: PMC4841525 DOI: 10.1371/journal.ppat.1005591] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 04/01/2016] [Indexed: 12/31/2022] Open
Abstract
Legionella pneumophila is a facultative intracellular bacterium that lives in aquatic environments where it parasitizes amoeba. However, upon inhalation of contaminated aerosols it can infect and replicate in human alveolar macrophages, which can result in Legionnaires' disease, a severe form of pneumonia. Upon experimental airway infection of mice, L. pneumophila is rapidly controlled by innate immune mechanisms. Here we identified, on a cell-type specific level, the key innate effector functions responsible for rapid control of infection. In addition to the well-characterized NLRC4-NAIP5 flagellin recognition pathway, tumor necrosis factor (TNF) and reactive oxygen species (ROS) are also essential for effective innate immune control of L. pneumophila. While ROS are essential for the bactericidal activity of neutrophils, alveolar macrophages (AM) rely on neutrophil and monocyte-derived TNF signaling via TNFR1 to restrict bacterial replication. This TNF-mediated antibacterial mechanism depends on the acidification of lysosomes and their fusion with L. pneumophila containing vacuoles (LCVs), as well as caspases with a minor contribution from cysteine-type cathepsins or calpains, and is independent of NLRC4, caspase-1, caspase-11 and NOX2. This study highlights the differential utilization of innate effector pathways to curtail intracellular bacterial replication in specific host cells upon L. pneumophila airway infection.
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Hanot Mambres D, Machelart A, Potemberg G, De Trez C, Ryffel B, Letesson JJ, Muraille E. Identification of Immune Effectors Essential to the Control of Primary and Secondary Intranasal Infection with Brucella melitensis in Mice. THE JOURNAL OF IMMUNOLOGY 2016; 196:3780-93. [PMID: 27036913 DOI: 10.4049/jimmunol.1502265] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 03/03/2016] [Indexed: 12/11/2022]
Abstract
The mucosal immune system represents the first line of defense against Brucella infection in nature. We used genetically deficient mice to identify the lymphocytes and signaling pathways implicated in the control of primary and secondary intranasal infection with B. melitensis Our analysis of primary infection demonstrated that the effectors implicated differ at the early and late stages and are dependent on the organ. TCR-δ, TAP1, and IL-17RA deficiency specifically affects early control of Brucella in the lungs, whereas MHC class II (MHCII) and IFN-γR deficiency impairs late control in the lungs, spleen, and liver. Interestingly, IL-12p35(-/-) mice display enhanced Brucella growth in the spleen but not in the lungs or liver. Secondary intranasal infections are efficiently contained in the lung. In contrast to an i.p. infectious model, in which IL-12p35, MHCII, and B cells are strictly required for the control of secondary infection, we observed that only TCR-β deficiency or simultaneous neutralization of IL-12p35- and IL-17A-dependent pathways impairs the memory protective response against a secondary intranasal infection. Protection is not affected by TCR-δ, MHCII, TAP1, B cell, IL-17RA, or IL-12p35 deficiency, suggesting that CD4(+) and CD8(+) α/β(+) T cells are sufficient to mount a protective immune response and that an IL-17A-mediated response can compensate for the partial deficiency of an IFN-γ-mediated response to control a Brucella challenge. These findings demonstrate that the nature of the protective memory response depends closely on the route of infection and highlights the role of IFN-γ-and IL-17RA-mediated responses in the control of mucosal infection by Brucella.
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Affiliation(s)
- Delphine Hanot Mambres
- Microorganisms Biology Research Unit (URBM), Laboratory of Immunology and Microbiology, Namur Research Institute for Life Sciences, University of Namur, 5000 Namur, Belgium
| | - Arnaud Machelart
- Microorganisms Biology Research Unit (URBM), Laboratory of Immunology and Microbiology, Namur Research Institute for Life Sciences, University of Namur, 5000 Namur, Belgium
| | - Georges Potemberg
- Microorganisms Biology Research Unit (URBM), Laboratory of Immunology and Microbiology, Namur Research Institute for Life Sciences, University of Namur, 5000 Namur, Belgium
| | - Carl De Trez
- Department of Molecular and Cellular Interactions, Flanders Interuniversity Institute for Biotechnology, Free University of Brussels (VUB), 1050 Brussels, Belgium
| | - Bernhard Ryffel
- Immunologie et Neurogénétique Expérimentales et Moléculaires - UMR7355 CNRS - Université d'Orléans, 45071 Orleans, France; Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Capetown 7925, South Africa; and
| | - Jean-Jacques Letesson
- Microorganisms Biology Research Unit (URBM), Laboratory of Immunology and Microbiology, Namur Research Institute for Life Sciences, University of Namur, 5000 Namur, Belgium
| | - Eric Muraille
- Microorganisms Biology Research Unit (URBM), Laboratory of Immunology and Microbiology, Namur Research Institute for Life Sciences, University of Namur, 5000 Namur, Belgium; Laboratoire de Parasitologie, Faculté de Médecine, Université Libre de Bruxelles, 1070 Bruxelles, Belgium
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10
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Puimège L, Libert C, Van Hauwermeiren F. Regulation and dysregulation of tumor necrosis factor receptor-1. Cytokine Growth Factor Rev 2014; 25:285-300. [PMID: 24746195 DOI: 10.1016/j.cytogfr.2014.03.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/10/2014] [Indexed: 01/18/2023]
Abstract
TNF is an essential regulator of the immune system. Dysregulation of TNF plays a role in the pathology of many auto-immune diseases. TNF-blocking agents have proven successful in the treatment of such diseases. Development of novel, safer or more effective drugs requires a deeper understanding of the regulation of the pro-inflammatory activities of TNF and its receptors. The ubiquitously expressed TNFR1 is responsible for most TNF effects, while TNFR2 has a limited expression pattern and performs immune-regulatory functions. Despite extensive knowledge of TNFR1 signaling, the regulation of TNFR1 expression, its modifications, localization and processing are less clear and the data are scattered. Here we review the current knowledge of TNFR1 regulation and discuss the impact this has on the host.
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Affiliation(s)
- Leen Puimège
- Inflammation Research Center, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Claude Libert
- Inflammation Research Center, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Filip Van Hauwermeiren
- Inflammation Research Center, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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11
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Waters JP, Pober JS, Bradley JR. Tumour necrosis factor in infectious disease. J Pathol 2013; 230:132-47. [PMID: 23460469 DOI: 10.1002/path.4187] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 02/15/2013] [Accepted: 02/23/2013] [Indexed: 12/12/2022]
Abstract
TNF signals through two distinct receptors, designated TNFR1 and TNFR2, which initiate diverse cellular effects that include cell survival, activation, differentiation, and proliferation and cell death. These cellular responses can promote immunological and inflammatory responses that eradicate infectious agents, but can also lead to local tissue injury at sites of infection and harmful systemic effects. Defining the molecular mechanisms involved in TNF responses, the effects of natural and experimental genetic diversity in TNF signalling and the effects of therapeutic blockade of TNF has increased our understanding of the key role that TNF plays in infectious disease.
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Affiliation(s)
- John P Waters
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
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12
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Wuerz TC, Mooney O, Keynan Y. Legionella pneumophila serotype 1 pneumonia in patient receiving adalimumab. Emerg Infect Dis 2013; 18:1872-4. [PMID: 23092579 PMCID: PMC3559148 DOI: 10.3201/eid1811.111505] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We describe a case of severe pneumonia caused by Legionella pneumophila serotype 1 in a woman receiving the tumor necrosis factor–α antagonist to treat rheumatoid arthritis. As use of tumor necrosis factor–α inhibitors increase, clinicians should consider their possible association with legionellosis.
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13
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Brown AS, van Driel IR, Hartland EL. Mouse models of Legionnaires' disease. Curr Top Microbiol Immunol 2013; 376:271-91. [PMID: 23918179 DOI: 10.1007/82_2013_349] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Legionella pneumophila is an accidental respiratory pathogen of humans that provokes a robust inflammatory response upon infection. While most people exposed to L. pneumophila will clear the infection, certain groups with underlying susceptibility will develop Legionnaires' disease. Mice, like most humans, are inherently resistant to L. pneumophila and infection of most inbred strains reflects the response of immune competent people to L. pneumophila exposure. Hence, the use of mouse models of L. pneumophila infection has taught us a great deal about the innate and adaptive factors that lead to successful clearance of the pathogen and avoidance of Legionnaires' disease. At the same time, L. pneumophila has provided new insight into innate immunity in general and is now a model pathogen with which to study acute lung inflammation and inflammasome activation. This chapter will explore the history and use of the mouse model of L. pneumophila infection and examine what we know about the innate and adaptive factors that contribute to the control of L. pneumophila in the mouse lung.
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Affiliation(s)
- Andrew S Brown
- Department of Biochemistry and Molecular Biology and the Bio21 Institute, University of Melbourne, Victoria, 3010, Australia
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14
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Kaku N, Sato T, Nakashima M, Nagashima S, Fukuda M, Hashiguchi K, Kaku N, Yanagihara K, Morinaga Y, Yanagihara K, Morinaga Y, Kohno S, Sakai T, Tominaga H, Wakigawa F. Detection of Legionella pneumophila serogroup 1 in blood cultures from a patient treated with tumor necrosis factor-alpha inhibitor. J Infect Chemother 2013; 19:166-70. [DOI: 10.1007/s10156-012-0459-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 07/10/2012] [Indexed: 10/28/2022]
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15
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Zaidi A, Jelveh S, Mahmood J, Hill RP. Effects of lipopolysaccharide on the response of C57BL/6J mice to whole thorax irradiation. Radiother Oncol 2012; 105:341-9. [PMID: 22985778 DOI: 10.1016/j.radonc.2012.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 06/28/2012] [Accepted: 08/11/2012] [Indexed: 01/15/2023]
Abstract
BACKGROUND AND PURPOSE Inflammatory and fibrogenic processes play a crucial role in the radiation-induced injury in the lung. The aim of the present study was to examine whether additive LPS exposure in the lung (to simulate respiratory infection) would affect pneumonitis or fibrosis associated with lung irradiation. MATERIAL AND METHODS Wildtype C57Bl/6J (WT-C57) and TNFα, TNFR1 and TNFR2 knockout ((-/-)) mice, in C57Bl/6J background, were given whole thorax irradiation (10 Gy) with or without post-irradiation intratracheal administration of LPS (50μg/mice). Functional deficit was examined by measuring breathing rate at various times after treatment. Real-time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and immunohistochemistry were used to analyze the protein expression and m-RNA of Interleukin-1 alpha (IL-1α), Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), Tumour Necrosis Factor alpha (TNFα) and Transforming Growth Factor beta (TGFβ) in the lung at various times after treatment. Inflammatory cells were detected by Mac-3 (macrophages) and Toluidine Blue (mast cells) staining. Collagen content was estimated by hydroxyproline (total collagen) and Sircol assay (soluble collagen). Levels of oxidative damage were assessed by 8-hydroxy-2-deoxyguanosine (8-OHdG) staining. RESULTS LPS exposure significantly attenuated the breathing rate increases following irradiation of WT-C57, TNFR1(-/-) and TNFR2(-/-)mice and to a lesser extent in TNFα(-/-) mice. Collagen content was significantly reduced after LPS treatment in WT-C57, TNFR1(-/-) and TNFα(-/-) mice and there was a trend in TNFR2(-/-) mice. Similarly there were lower levels of inflammatory cells and cytokines in the LPS treated mice. CONCLUSIONS This study reveals a mitigating effect of early exposure to LPS on injury caused by irradiation on lungs of C57Bl mice. The results suggest that immediate infection post irradiation may not impact lung response negatively in radiation-accident victims, however, further studies are required in different animal models, and with specific infectious agents, to confirm and extend our findings.
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Affiliation(s)
- Asif Zaidi
- Ontario Cancer Institute, Toronto, Ontario, Canada
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16
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Schuelein R, Ang DKY, van Driel IR, Hartland EL. Immune Control of Legionella Infection: An in vivo Perspective. Front Microbiol 2011; 2:126. [PMID: 21687433 PMCID: PMC3109619 DOI: 10.3389/fmicb.2011.00126] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 05/23/2011] [Indexed: 11/13/2022] Open
Abstract
Legionella pneumophila is an intracellular pathogen that replicates within alveolar macrophages. Through its ability to activate multiple host innate immune components, L. pneumophila has emerged as a useful tool to dissect inflammatory signaling pathways in macrophages. However the resolution of L. pneumophila infection in the lung requires multiple cell types and abundant cross talk between immune cells. Few studies have examined the coordination of events that lead to effective immune control of the pathogen. Here we discuss L. pneumophila interactions with macrophages and dendritic cell subsets and highlight the paucity of knowledge around how these interactions recruit and activate other immune effector cells in the lung.
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Affiliation(s)
- Ralf Schuelein
- Department of Microbiology and Immunology, University of Melbourne Parkville, Victoria, Australia
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17
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Legionella pneumophila type II secretion dampens the cytokine response of infected macrophages and epithelia. Infect Immun 2011; 79:1984-97. [PMID: 21383054 DOI: 10.1128/iai.01077-10] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The type II secretion (T2S) system of Legionella pneumophila is required for the ability of the bacterium to grow within the lungs of A/J mice. By utilizing mutants lacking T2S (lsp), we now document that T2S promotes the intracellular infection of both multiple types of macrophages and lung epithelia. Following infection of macrophages, lsp mutants (but not a complemented mutant) elicited significantly higher levels of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), IL-10, IL-8, IL-1β, and MCP-1 within tissue culture supernatants. A similar result was obtained with infected lung epithelial cell lines and the lungs of infected A/J mice. Infection with a mutant specifically lacking the T2S-dependent ProA protease (but not a complemented proA mutant) resulted in partial elevation of cytokine levels. These data demonstrate that the T2S system of L. pneumophila dampens the cytokine/chemokine output of infected host cells. Upon quantitative reverse transcription (RT)-PCR analysis of infected host cells, an lspF mutant, but not the proA mutant, produced significantly higher levels of cytokine transcripts, implying that some T2S-dependent effectors dampen signal transduction and transcription but that others, such as ProA, act at a posttranscriptional step in cytokine expression. In summary, the impact of T2S on lung infection is a combination of at least three factors: the promotion of growth in macrophages, the facilitation of growth in epithelia, and the dampening of the chemokine and cytokine output from infected host cells. To our knowledge, these data are the first to identify a link between a T2S system and the modulation of immune factors following intracellular infection.
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18
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Abstract
The genus Legionella contains more than 50 species, of which at least 24 have been associated with human infection. The best-characterized member of the genus, Legionella pneumophila, is the major causative agent of Legionnaires' disease, a severe form of acute pneumonia. L. pneumophila is an intracellular pathogen, and as part of its pathogenesis, the bacteria avoid phagolysosome fusion and replicate within alveolar macrophages and epithelial cells in a vacuole that exhibits many characteristics of the endoplasmic reticulum (ER). The formation of the unusual L. pneumophila vacuole is a feature of its interaction with the host, yet the mechanisms by which the bacteria avoid classical endosome fusion and recruit markers of the ER are incompletely understood. Here we review the factors that contribute to the ability of L. pneumophila to infect and replicate in human cells and amoebae with an emphasis on proteins that are secreted by the bacteria into the Legionella vacuole and/or the host cell. Many of these factors undermine eukaryotic trafficking and signaling pathways by acting as functional and, in some cases, structural mimics of eukaryotic proteins. We discuss the consequences of this mimicry for the biology of the infected cell and also for immune responses to L. pneumophila infection.
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19
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Edgel KA, LeBoeuf RC, Oram JF. Tumor necrosis factor-α and lymphotoxin-α increase macrophage ABCA1 by gene expression and protein stabilization via different receptors. Atherosclerosis 2010; 209:387-92. [DOI: 10.1016/j.atherosclerosis.2009.10.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 09/07/2009] [Accepted: 10/11/2009] [Indexed: 11/15/2022]
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20
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Fujita M, Harada E, Matsumoto T, Mizuta Y, Ikegame S, Ouchi H, Inoshima I, Yoshida S, Watanabe K, Nakanishi Y. Impaired host defence against Mycobacterium avium in mice with chronic granulomatous disease. Clin Exp Immunol 2010; 160:457-60. [PMID: 20089078 DOI: 10.1111/j.1365-2249.2010.04092.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Patients with chronic granulomatous disease (CGD), an inherited disorder of phagocytic cells, often contract recurrent life-threatening bacterial and fungal infections. CGD is considered to arise from a functional defect of the O(2)-generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in phagocytes. To determine whether or not NADPH oxidase is crucial to the host defence against Mycobacterium avium, we investigated the response against M. avium using CGD model mice (gp91-phox(-)) of C57BL/6 strain. A tracheal injection of 1 x 10(7) colony-forming units (CFU)/head of M. avium strain FN into the CGD mice resulted in a pulmonary infection, while also increasing the mortality rate. In contrast, normal C57BL/6 mice injected with same dose of the organisms did not develop severe pulmonary infection and were able to survive through 2 months of observation. The macrophages obtained from the CGD mice were observed to have a higher burden of the bacterial growth than macrophages from normal C57BL/6 mice. These results suggest that the defect of the NADPH oxidase function impairs the host defence against M. avium infection.
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Affiliation(s)
- M Fujita
- Research Institute for Diseases of the Chest, Kyushu University, Fukuoka, Japan.
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21
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Li L, Qiu L, Song L, Song X, Zhao J, Wang L, Mu C, Zhang H. First molluscan TNFR homologue in Zhikong scallop: molecular characterization and expression analysis. FISH & SHELLFISH IMMUNOLOGY 2009; 27:625-632. [PMID: 19632334 DOI: 10.1016/j.fsi.2009.07.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 07/18/2009] [Accepted: 07/18/2009] [Indexed: 05/28/2023]
Abstract
Tumor necrosis factor receptors (TNFRs) are a superfamily of proteins characterized by the unique cysteine-rich domain (CRD) and their important roles in diverse physiological and pathological events such as inflammation, apoptosis, autoimmunity and organogenesis. The first member of the molluscan TNFR family, designated as CfTNFR, was identified from Zhikong scallop Chlamys farreri by expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of CfTNFR was of 1334 bp, consisting of a 5' UTR of 17 bp, a 3' UTR of 69 bp with a poly (A) tail, and an open reading frame (ORF) of 1248 bp encoding a polypeptide of 415 amino acids with a theoretical isoelectric point of 8.33 and predicted molecular weight of 47.07 kDa. There were a signal peptide, a CRD, a transmembrane region and a death domain in the deduced amino acid sequence of CfTNFR, suggesting that it was a typical type I membrane protein. The high identities (22-40%) of CfTNFR with other TNFR superfamily members indicated that CfTNFR should be a member of TNFR superfamily, and moreover, it should be the first death domain-containing TNFR found in invertebrates. Phylogenetic analysis revealed that CfTNFR was closely related to TNFR-like proteins from Strongylocentrotus purpuratus, Drosophila melanogaster and Ciona intestinalis, and they formed a separate branch apart from vertebrate TNFRs. The spatial expression of CfTNFR transcripts in healthy and bacteria challenged scallops was examined by quantitative real-time PCR. CfTNFR transcripts could be detected in all tested tissues, including haemocytes, gonad, gill, mantle and hepatopancreas, and significantly up-regulated in the tissues of gonad, gill, mantle and hepatopancreas after Listonella anguillarum challenge, indicating that CfTNFR was constitutive and inducible acute-phase protein involved in immune defence. The present results suggested the existence of the TNFR-like molecules and TNF-TNFR system in low invertebrates, and provided new insights into the role of CfTNFR in scallop innate immune responses to invading microorganisms.
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Affiliation(s)
- Ling Li
- The Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Rd, Qingdao 266071, China
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22
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Leichtle A, Hernandez M, Pak K, Yamasaki K, Cheng CF, Webster NJ, Ryan AF, Wasserman SI. TLR4-mediated induction of TLR2 signaling is critical in the pathogenesis and resolution of otitis media. Innate Immun 2009; 15:205-15. [PMID: 19586996 DOI: 10.1177/1753425909103170] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Otitis media is the most prevalent childhood disease in developed countries. The involvement of Toll-like receptors (TLRs) in otitis media pathophysiology has been implicated by studies in cell lines and association studies of TLR gene polymorphisms. However, precise functions of TLRs in the etiology of otitis media in vivo have not been examined. We investigated the inflammatory response to nontypeable Haemophilus influenzae using a model of otitis media in wild-type, TLR2(- /-) and TLR4(-/ -) mice by gene microarray, qPCR, immunohistochemistry, Western blot analysis and histopathology. Toll-like receptor-2(- /-) and TLR4(- /-) mice exhibited a more profound, persistent inflammation with impaired bacterial clearance compared to controls. While wild-type mice induced tumor necrosis factor-a (TNF) after non-typeable H. influenzae challenge, TLR2(-/-) and TLR4(-/-) mice lack TNF induction in the early phase of otitis media. Moreover, lack of TLR2 resulted in a late increase in IL-10 expression and prolonged failure to clear bacteria. Toll-like receptor-4(-/- ) mice showed impaired early bacterial clearance and loss of TLR2 induction in early otitis media. Our results demonstrate that both TLR2 and TLR4 signalling are critical to the regulation of infection in non-typeable H. influenzae-induced otitis media. Toll-like receptor-4 signalling appears to induce TLR2 expression, and TLR2 activation is critical for bacterial clearance and timely resolution of otitis media.
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Affiliation(s)
- Anke Leichtle
- Department of Surgery/Otolaryngology, University of California San Diego, La Jolla, California 92093, USA
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