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Selvaraj C, Vierra M, Dinesh DC, Abhirami R, Singh SK. Structural insights of macromolecules involved in bacteria-induced apoptosis in the pathogenesis of human diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 126:1-38. [PMID: 34090612 DOI: 10.1016/bs.apcsb.2021.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Numbers of pathogenic bacteria can induce apoptosis in human host cells and modulate the cellular pathways responsible for inducing or inhibiting apoptosis. These pathogens are significantly recognized by host proteins and provoke the multitude of several signaling pathways and alter the cellular apoptotic stimuli. This process leads the bacterial entry into the mammalian cells and evokes a variety of responses like phagocytosis, release of mitochondrial cytochrome c, secretion of bacterial effectors, release of both apoptotic and inflammatory cytokines, and the triggering of apoptosis. Several mechanisms are involved in bacteria-induced apoptosis including, initiation of the endogenous death machinery, pore-forming proteins, and secretion of superantigens. Either small molecules or proteins may act as a binding partner responsible for forming the protein complexes and regulate enzymatic activity via protein-protein interactions. The bacteria induce apoptosis, attack the human cell and gain control over various types of cells and tissue. Since these processes are intricate in the defense mechanisms of host organisms against pathogenic bacteria and play an important function in host-pathogen interactions. In this chapter, we focus on the various bacterial-induced apoptosis mechanisms in host cells and discuss the important proteins and bacterial effectors that trigger the host cell apoptosis. The structural characterization of bacterial effector proteins and their interaction with human host cells are also considered.
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Affiliation(s)
- Chandrabose Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India.
| | - Marisol Vierra
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | | | - Rajaram Abhirami
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
| | - Sanjeev Kumar Singh
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India.
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2
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Alphonse N, Dickenson RE, Odendall C. Interferons: Tug of War Between Bacteria and Their Host. Front Cell Infect Microbiol 2021; 11:624094. [PMID: 33777837 PMCID: PMC7988231 DOI: 10.3389/fcimb.2021.624094] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/05/2021] [Indexed: 12/30/2022] Open
Abstract
Type I and III interferons (IFNs) are archetypally antiviral cytokines that are induced in response to recognition of foreign material by pattern recognition receptors (PRRs). Though their roles in anti-viral immunity are well established, recent evidence suggests that they are also crucial mediators of inflammatory processes during bacterial infections. Type I and III IFNs restrict bacterial infection in vitro and in some in vivo contexts. IFNs mainly function through the induction of hundreds of IFN-stimulated genes (ISGs). These include PRRs and regulators of antimicrobial signaling pathways. Other ISGs directly restrict bacterial invasion or multiplication within host cells. As they regulate a diverse range of anti-bacterial host responses, IFNs are an attractive virulence target for bacterial pathogens. This review will discuss the current understanding of the bacterial effectors that manipulate the different stages of the host IFN response: IFN induction, downstream signaling pathways, and target ISGs.
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Affiliation(s)
- Noémie Alphonse
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
- Immunoregulation Laboratory, Francis Crick Institute, London, United Kingdom
| | - Ruth E. Dickenson
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
| | - Charlotte Odendall
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, London, United Kingdom
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Kienes I, Weidl T, Mirza N, Chamaillard M, Kufer TA. Role of NLRs in the Regulation of Type I Interferon Signaling, Host Defense and Tolerance to Inflammation. Int J Mol Sci 2021; 22:1301. [PMID: 33525590 PMCID: PMC7865845 DOI: 10.3390/ijms22031301] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/12/2022] Open
Abstract
Type I interferon signaling contributes to the development of innate and adaptive immune responses to either viruses, fungi, or bacteria. However, amplitude and timing of the interferon response is of utmost importance for preventing an underwhelming outcome, or tissue damage. While several pathogens evolved strategies for disturbing the quality of interferon signaling, there is growing evidence that this pathway can be regulated by several members of the Nod-like receptor (NLR) family, although the precise mechanism for most of these remains elusive. NLRs consist of a family of about 20 proteins in mammals, which are capable of sensing microbial products as well as endogenous signals related to tissue injury. Here we provide an overview of our current understanding of the function of those NLRs in type I interferon responses with a focus on viral infections. We discuss how NLR-mediated type I interferon regulation can influence the development of auto-immunity and the immune response to infection.
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Affiliation(s)
- Ioannis Kienes
- Department of Immunology, Institute for Nutritional Medicine, University of Hohenheim, 70599 Stuttgart, Germany; (I.K.); (T.W.); (N.M.)
| | - Tanja Weidl
- Department of Immunology, Institute for Nutritional Medicine, University of Hohenheim, 70599 Stuttgart, Germany; (I.K.); (T.W.); (N.M.)
| | - Nora Mirza
- Department of Immunology, Institute for Nutritional Medicine, University of Hohenheim, 70599 Stuttgart, Germany; (I.K.); (T.W.); (N.M.)
| | | | - Thomas A. Kufer
- Department of Immunology, Institute for Nutritional Medicine, University of Hohenheim, 70599 Stuttgart, Germany; (I.K.); (T.W.); (N.M.)
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Kiran MD, Bala S, Hirshberg M, Balaban N. YhgC protects Bacillus anthracis from oxidative stress. Int J Artif Organs 2018. [DOI: 10.1177/039139881003300905] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Bacillus anthracis can cause lethal inhalational anthrax and can be used as a bioweapon due to its ability to form spores and to survive under various environmental stress conditions. YhgC in bacilli are structural homologues of TRAP, a protein involved in stress response in staphylococci. To test the role of YhgC in B. anthracis, YhgC gene was deleted in B. anthracis strain Sterne and parent and mutant strains tested. Immunolocalization studies indicated that YhgC is clustered both on the cell surface and within the cytoplasm. Phenotypic analyses indicated that YhgC is an important factor for oxidative stress tolerance and for macrophage infection in vitro. Accordingly, transcriptomics studies indicated that yhgC has a profound effect on genes encoding for stress response regulatory proteins where it negatively regulates the expression of genes encoding for Class I and Class III stress response proteins belonging to the regulons hrcA (hrcA, grpE, dnaK, dnaJ, groEL and groES) and ctsR (ctsR, mcsA, mcsB, clpC/mecB, clpP1). Proteomics studies also indicated that YhgC positively regulates the expression of ClpP-2 and camelysin, which are proteins involved in adaptive responses and pathogenesis in various Gram-positive bacteria. Put together, these results suggest that YhgC is important for the survival of B. anthracis under oxidative stress conditions and thus inhibition of YhgC may compromise the ability of the bacteria to survive within the host.
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Affiliation(s)
- Madanahally D. Kiran
- Tufts University, Cummings School of Veterinary Medicine, North Grafton, MA - USA
- IQUUM Inc, Marlborough MA - USA
| | - Shashi Bala
- University of Massachusetts Medical School, Worcester, MA - USA
| | - Miriam Hirshberg
- EMBL Outstation – Hinxton, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge - United Kingdom
| | - Naomi Balaban
- Tufts University, Cummings School of Veterinary Medicine, North Grafton, MA - USA
- Yale University, Department of Chemical Engineering, New Haven, CT - USA
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5
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Kotredes KP, Thomas B, Gamero AM. The Protective Role of Type I Interferons in the Gastrointestinal Tract. Front Immunol 2017; 8:410. [PMID: 28428788 PMCID: PMC5382159 DOI: 10.3389/fimmu.2017.00410] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/22/2017] [Indexed: 12/18/2022] Open
Abstract
The immune system of the gastrointestinal (GI) tract manages the significant task of recognizing and eliminating pathogens while maintaining tolerance of commensal bacteria. Dysregulation of this delicate balance can be detrimental, resulting in severe inflammation, intestinal injury, and cancer. Therefore, mechanisms to relay important signals regulating cell growth and immune reactivity must be in place to support GI homeostasis. Type I interferons (IFN-I) are a family of pleiotropic cytokines, which exert a wide range of biological effects including promotion of both pro- and anti-inflammatory activities. Using animal models of colitis, investigations into the regulation of intestinal epithelium inflammation highlight the role of IFN-I signaling during fine modulation of the immune system. The intestinal epithelium of the gut guides the immune system to differentiate between commensal and pathogenic microbiota, which relies on intimate links with the IFN-I signal-transduction pathway. The current paradigm depicts an IFN-I-induced antiproliferative state in the intestinal epithelium enabling cell differentiation, cell maturation, and proper intestinal barrier function, strongly supporting its role in maintaining baseline immune activity and clearance of damaged epithelia or pathogens. In this review, we will highlight the importance of IFN-I in intestinal homeostasis by discussing its function in inflammation, immunity, and cancer.
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Affiliation(s)
- Kevin P Kotredes
- Department of Medical Genetics and Molecular Biochemistry, Temple University School of Medicine, Philadelphia, PA, USA
| | - Brianna Thomas
- Department of Medical Genetics and Molecular Biochemistry, Temple University School of Medicine, Philadelphia, PA, USA
| | - Ana M Gamero
- Department of Medical Genetics and Molecular Biochemistry, Temple University School of Medicine, Philadelphia, PA, USA
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Gao X, Pham TH, Feuerbacher LA, Chen K, Hays MP, Singh G, Rueter C, Hurtado-Guerrero R, Hardwidge PR. Citrobacter rodentium NleB Protein Inhibits Tumor Necrosis Factor (TNF) Receptor-associated Factor 3 (TRAF3) Ubiquitination to Reduce Host Type I Interferon Production. J Biol Chem 2016; 291:18232-8. [PMID: 27387501 PMCID: PMC5000071 DOI: 10.1074/jbc.m116.738278] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/14/2016] [Indexed: 11/06/2022] Open
Abstract
Interferon signaling plays important roles in both intestinal homeostasis and in the host response to pathogen infection. The extent to which bacterial pathogens inhibit this host pathway is an understudied area of investigation. We characterized Citrobacter rodentium strains bearing deletions in individual type III secretion system effector genes to determine whether this pathogen inhibits the host type I IFN response and which effector is responsible. The NleB effector limited host IFN-β production by inhibiting Lys(63)-linked ubiquitination of TNF receptor-associated factor 3 (TRAF3). Inhibition was dependent on the glycosyltransferase activity of NleB. GAPDH, a target of NleB during infection, bound to TRAF3 and was required for maximal TRAF3 ubiquitination. NleB glycosyltransferase activity inhibited GAPDH-TRAF3 binding, resulting in reduced TRAF3 ubiquitination. Collectively, our data reveal important interplay between GAPDH and TRAF3 and suggest a mechanism by which the NleB effector inhibits type I IFN signaling.
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Affiliation(s)
- Xiaofei Gao
- From the Whitehead Institute, Cambridge, Massachusetts 02142
| | - Thanh H Pham
- Case Western Reserve University, Cleveland, Ohio 44106
| | - Leigh Ann Feuerbacher
- the College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506
| | - Kangming Chen
- the College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506
| | - Michael P Hays
- the College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506
| | - Gyanendra Singh
- the National Institute of Occupational Health, Meghani Nagar, Ahmedabad 380016, Gujarat, India
| | - Christian Rueter
- the Institute of Infectiology, University of Münster, D-48149 Münster, Germany, and
| | - Ramon Hurtado-Guerrero
- the Fundacion ARAID, Edificio CEEI ARAGÓN and Institute of Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, BIFI-IQFR (CSIC) Joint Unit, Mariano Esquillor s/n, Campus Rio Ebro, Edificio I+D, 50018 Zaragoza, Spain
| | - Philip R Hardwidge
- the College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506,
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McNab F, Mayer-Barber K, Sher A, Wack A, O'Garra A. Type I interferons in infectious disease. Nat Rev Immunol 2015; 15:87-103. [PMID: 25614319 DOI: 10.1038/nri3787] [Citation(s) in RCA: 1740] [Impact Index Per Article: 193.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Type I interferons (IFNs) have diverse effects on innate and adaptive immune cells during infection with viruses, bacteria, parasites and fungi, directly and/or indirectly through the induction of other mediators. Type I IFNs are important for host defence against viruses. However, recently, they have been shown to cause immunopathology in some acute viral infections, such as influenza virus infection. Conversely, they can lead to immunosuppression during chronic viral infections, such as lymphocytic choriomeningitis virus infection. During bacterial infections, low levels of type I IFNs may be required at an early stage, to initiate cell-mediated immune responses. High concentrations of type I IFNs may block B cell responses or lead to the production of immunosuppressive molecules, and such concentrations also reduce the responsiveness of macrophages to activation by IFNγ, as has been shown for infections with Listeria monocytogenes and Mycobacterium tuberculosis. Recent studies in experimental models of tuberculosis have demonstrated that prostaglandin E2 and interleukin-1 inhibit type I IFN expression and its downstream effects, demonstrating that a cross-regulatory network of cytokines operates during infectious diseases to provide protection with minimum damage to the host.
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Affiliation(s)
- Finlay McNab
- 1] Allergic Inflammation Discovery Performance Unit, Respiratory Disease Respiratory Research and Development, GlaxoSmithKline, Stevenage, Hertfordshire SG1 2NY, UK. [2] Division of Immunoregulation, Medical Research Council (MRC) National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
| | - Katrin Mayer-Barber
- Immunobiology Section, Laboratory of Parasitic Diseases (LPD), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
| | - Alan Sher
- Immunobiology Section, Laboratory of Parasitic Diseases (LPD), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
| | - Andreas Wack
- Division of Immunoregulation, Medical Research Council (MRC) National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
| | - Anne O'Garra
- 1] Division of Immunoregulation, Medical Research Council (MRC) National Institute for Medical Research, Mill Hill, London NW7 1AA, UK. [2] National Heart and Lung Institute (NHLI), Faculty of Medicine, Imperial College London, London, UK
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8
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Furuya Y, Müllbacher A. Type I IFN exhaustion is a host defence protecting against secondary bacterial infections. Scand J Immunol 2013; 78:395-400. [PMID: 24006947 PMCID: PMC7169485 DOI: 10.1111/sji.12107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 08/28/2013] [Indexed: 12/19/2022]
Abstract
Type I interferons (IFN-I) have been known for decades for their indispensable role in curtailing viral infections. It is, however, now also increasingly recognized that IFN-I is detrimental to the host in combating a number of bacterial infections. We have previously reported that viral infections induce partial lymphocyte activation, characterized by significant increases in the cell surface expression of CD69 and CD86, but not CD25. This systemic partial activation of lymphocytes, mediated by IFN-I, is rapid and is followed by a period of IFN-I unresponsiveness. Here we propose that IFN-I exhaustion that occurs soon after a primary viral infection may be a host response protecting it from secondary bacterial infections.
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Affiliation(s)
- Y. Furuya
- Department of Emerging Pathogens and VaccinesJohn Curtin School of Medical ResearchAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - A. Müllbacher
- Department of ImmunologyJohn Curtin School of Medical ResearchAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
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Corre JP, Piris-Gimenez A, Moya-Nilges M, Jouvion G, Fouet A, Glomski IJ, Mock M, Sirard JC, Goossens PL. In vivo germination of Bacillus anthracis spores during murine cutaneous infection. J Infect Dis 2012; 207:450-7. [PMID: 23148288 DOI: 10.1093/infdis/jis686] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Germination is a key step for successful Bacillus anthracis colonization and systemic dissemination. Few data are available on spore germination in vivo, and the necessity of spore and host cell interactions to initiate germination is unclear. METHODS To investigate the early interactions between B. anthracis spores and cutaneous tissue, spores were inoculated in an intraperitoneal cell-free device in guinea pigs or into the pinna of mice. Germination and bacterial growth were analyzed through colony-forming unit enumeration and electron microscopy. RESULTS In the guinea pig model, germination occurred in vivo in the absence of cell contact. Similarly, in the mouse ear, germination started within 15 minutes after inoculation, and germinating spores were found in the absence of surrounding cells. Germination was not observed in macrophage-rich draining lymph nodes, liver, and spleen. Edema and lethal toxin production were not required for germination, as a toxin-deficient strain was as effective as a Sterne-like strain. B. anthracis growth was locally controlled for 6 hours. CONCLUSIONS Spore germination involving no cell interactions can occur in vivo, suggesting that diffusible germinants or other signals appear sufficient. Different host tissues display drastic differences in germination-triggering capacity. Initial control of bacterial growth suggests a therapeutic means to exploit host innate defenses to hinder B. anthracis colonization.
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Affiliation(s)
- Jean-Philippe Corre
- Toxines et Pathogénie Bactériennes, Pathogénie des Toxi-Infections Bactériennes, Centre National de la Recherche Scientifique, Paris, France
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Gomes MTR, Campos PC, de Almeida LA, Oliveira FS, Costa MMS, Marim FM, Pereira GSM, Oliveira SC. The role of innate immune signals in immunity to Brucella abortus. Front Cell Infect Microbiol 2012; 2:130. [PMID: 23112959 PMCID: PMC3480720 DOI: 10.3389/fcimb.2012.00130] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 10/04/2012] [Indexed: 01/18/2023] Open
Abstract
Innate immunity serves as the first line of defense against infectious agents such as intracellular bacteria. The innate immune platform includes Toll-like receptors (TLRs), retinoid acid-inducible gene-I-like receptors and other cytosolic nucleic acid sensors, nucleotide-binding and oligomerization domain-like receptors, adaptors, kinases and other signaling molecules that are required to elicit effective responses against different pathogens. Our research group has been using the Gram-negative bacteria Brucella abortus as a model of pathogen. We have demonstrated that B. abortus triggers MAPK and NF-κB signaling pathways in macrophages in a MyD88 and IRAK-4-dependent manner. Furthermore, we claimed that so far TLR9 is the most important single TLR during Brucella infection. The identification of host receptors that recognize pathogen-derived nucleic acids has revealed an essential role for nucleic acid sensing in the triggering of immunity to intracellular pathogens. Besides TLRs, herein we describe recent advances in NOD1, NOD2, and type I IFN receptors in innate immune pathways during B. abortus infection.
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Affiliation(s)
| | | | | | | | | | | | | | - Sergio C. Oliveira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas GeraisBelo Horizonte, MG, Brazil
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Anthrax lethal toxin and the induction of CD4 T cell immunity. Toxins (Basel) 2012; 4:878-99. [PMID: 23162703 PMCID: PMC3496994 DOI: 10.3390/toxins4100878] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 10/08/2012] [Accepted: 10/10/2012] [Indexed: 12/27/2022] Open
Abstract
Bacillus anthracis secretes exotoxins which act through several mechanisms including those that can subvert adaptive immunity with respect both to antigen presenting cell and T cell function. The combination of Protective Antigen (PA) and Lethal Factor (LF) forming Lethal Toxin (LT), acts within host cells to down-regulate the mitogen activated protein kinase (MAPK) signaling cascade. Until recently the MAPK kinases were the only known substrate for LT; over the past few years it has become evident that LT also cleaves Nlrp1, leading to inflammasome activation and macrophage death. The predicted downstream consequences of subverting these important cellular pathways are impaired antigen presentation and adaptive immunity. In contrast to this, recent work has indicated that robust memory T cell responses to B. anthracis antigens can be identified following natural anthrax infection. We discuss how LT affects the adaptive immune response and specifically the identification of B. anthracis epitopes that are both immunogenic and protective with the potential for inclusion in protein sub-unit based vaccines.
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12
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Weiden MD, Naveed B, Kwon S, Segal LN, Cho SJ, Tsukiji J, Kulkarni R, Comfort AL, Kasturiarachchi KJ, Prophete C, Cohen MD, Chen LC, Rom WN, Prezant DJ, Nolan A. Comparison of WTC dust size on macrophage inflammatory cytokine release in vivo and in vitro. PLoS One 2012; 7:e40016. [PMID: 22815721 PMCID: PMC3399845 DOI: 10.1371/journal.pone.0040016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/30/2012] [Indexed: 11/18/2022] Open
Abstract
Background The WTC collapse exposed over 300,000 people to high concentrations of WTC-PM; particulates up to ∼50 mm were recovered from rescue workers’ lungs. Elevated MDC and GM-CSF independently predicted subsequent lung injury in WTC-PM-exposed workers. Our hypotheses are that components of WTC dust strongly induce GM-CSF and MDC in AM; and that these two risk factors are in separate inflammatory pathways. Methodology/Principal Findings Normal adherent AM from 15 subjects without WTC-exposure were incubated in media alone, LPS 40 ng/mL, or suspensions of WTC-PM10–53 or WTC-PM2.5 at concentrations of 10, 50 or 100 µg/mL for 24 hours; supernatants assayed for 39 chemokines/cytokines. In addition, sera from WTC-exposed subjects who developed lung injury were assayed for the same cytokines. In the in vitro studies, cytokines formed two clusters with GM-CSF and MDC as a result of PM10–53 and PM2.5. GM-CSF clustered with IL-6 and IL-12(p70) at baseline, after exposure to WTC-PM10–53 and in sera of WTC dust-exposed subjects (n = 70) with WTC lung injury. Similarly, MDC clustered with GRO and MCP-1. WTC-PM10–53 consistently induced more cytokine release than WTC-PM2.5 at 100 µg/mL. Individual baseline expression correlated with WTC-PM-induced GM-CSF and MDC. Conclusions WTC-PM10–53 induced a stronger inflammatory response by human AM than WTC-PM2.5. This large particle exposure may have contributed to the high incidence of lung injury in those exposed to particles at the WTC site. GM-CSF and MDC consistently cluster separately, suggesting a role for differential cytokine release in WTC-PM injury. Subject-specific response to WTC-PM may underlie individual susceptibility to lung injury after irritant dust exposure.
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Affiliation(s)
- Michael D. Weiden
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
- Department of Environmental Medicine, New York University School of Medicine, Tuxedo Park, New York, United States of America
- Bureau of Health Services and Office of Medical Affairs, Fire Department of New York, Brooklyn, New York, United States of America
| | - Bushra Naveed
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Sophia Kwon
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Leopoldo N. Segal
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Soo Jung Cho
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Jun Tsukiji
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Rohan Kulkarni
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Ashley L. Comfort
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Kusali J. Kasturiarachchi
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Colette Prophete
- Department of Environmental Medicine, New York University School of Medicine, Tuxedo Park, New York, United States of America
- Ruth L. and David S. Gottesman Institute for Stem and Regenerative Medicine Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Mitchell D. Cohen
- Department of Environmental Medicine, New York University School of Medicine, Tuxedo Park, New York, United States of America
| | - Lung-Chi Chen
- Department of Environmental Medicine, New York University School of Medicine, Tuxedo Park, New York, United States of America
| | - William N. Rom
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
- Department of Environmental Medicine, New York University School of Medicine, Tuxedo Park, New York, United States of America
| | - David J. Prezant
- Bureau of Health Services and Office of Medical Affairs, Fire Department of New York, Brooklyn, New York, United States of America
- Pulmonary Medicine Division, Department of Medicine, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Anna Nolan
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
- Department of Environmental Medicine, New York University School of Medicine, Tuxedo Park, New York, United States of America
- Bureau of Health Services and Office of Medical Affairs, Fire Department of New York, Brooklyn, New York, United States of America
- * E-mail:
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Uchiyama S, Andreoni F, Schuepbach RA, Nizet V, Zinkernagel AS. DNase Sda1 allows invasive M1T1 Group A Streptococcus to prevent TLR9-dependent recognition. PLoS Pathog 2012; 8:e1002736. [PMID: 22719247 PMCID: PMC3375267 DOI: 10.1371/journal.ppat.1002736] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 04/20/2012] [Indexed: 01/09/2023] Open
Abstract
Group A Streptococcus (GAS) has developed a broad arsenal of virulence factors that serve to circumvent host defense mechanisms. The virulence factor DNase Sda1 of the hyperinvasive M1T1 GAS clone degrades DNA-based neutrophil extracellular traps allowing GAS to escape extracellular killing. TLR9 is activated by unmethylated CpG-rich bacterial DNA and enhances innate immune resistance. We hypothesized that Sda1 degradation of bacterial DNA could alter TLR9-mediated recognition of GAS by host innate immune cells. We tested this hypothesis using a dual approach: loss and gain of function of DNase in isogenic GAS strains and presence and absence of TLR9 in the host. Either DNA degradation by Sda1 or host deficiency of TLR9 prevented GAS induced IFN-α and TNF-α secretion from murine macrophages and contributed to bacterial survival. Similarly, in a murine necrotizing fasciitis model, IFN-α and TNF-α levels were significantly decreased in wild type mice infected with GAS expressing Sda1, whereas no such Sda1-dependent effect was seen in a TLR9-deficient background. Thus GAS Sda1 suppressed both the TLR9-mediated innate immune response and macrophage bactericidal activity. Our results demonstrate a novel mechanism of bacterial innate immune evasion based on autodegradation of CpG-rich DNA by a bacterial DNase.
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Affiliation(s)
- Satoshi Uchiyama
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Division of Surgical Intensive Care, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Federica Andreoni
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Reto A. Schuepbach
- Division of Surgical Intensive Care, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Victor Nizet
- Department of Pediatrics, Division of Pharmacology & Drug Discovery and Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Annelies S. Zinkernagel
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- * E-mail:
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14
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Bensman MD, Mackie RS, Minter ZA, Gutting BW. Effect of animal sera on Bacillus anthracis Sterne spore germination and vegetative cell growth. J Appl Microbiol 2012; 113:276-83. [PMID: 22515644 DOI: 10.1111/j.1365-2672.2012.05314.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
AIMS The aims of this work were to investigate the effects of sera on B. anthracis Sterne germination and growth. Sera examined included human, monkey and rabbit sera, as well as sera from eight other species. METHODS AND RESULTS Standard dilution plate assay (with and without heat kill) was used as a measure of germination, and spectroscopy was used to measure growth. In addition, a Coulter Counter particle counter was used to monitor germination and growth based on bacterial size. Spores germinated best in foetal bovine and monkey sera, moderately with human sera and showed limited germination in the presence of rabbit or rat sera. Vegetative bacteria grew best in foetal bovine sera and moderately in rabbit sera. Human and monkey sera supported little growth of vegetative bacteria. CONCLUSION The data suggested sera can have a significant impact on germination and growth of Sterne bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY These data should be considered when conducting in vitro cell culture studies and may aid in interpreting in vivo infection studies.
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Affiliation(s)
- M D Bensman
- Dahlgren Division, CBR Concepts and Experimentation Branch-Z21, Naval Surface Warfare Center, Dahlgren, VA, USA
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15
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Klezovich-Bénard M, Corre JP, Jusforgues-Saklani H, Fiole D, Burjek N, Tournier JN, Goossens PL. Mechanisms of NK cell-macrophage Bacillus anthracis crosstalk: a balance between stimulation by spores and differential disruption by toxins. PLoS Pathog 2012; 8:e1002481. [PMID: 22253596 PMCID: PMC3257302 DOI: 10.1371/journal.ppat.1002481] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 11/28/2011] [Indexed: 01/08/2023] Open
Abstract
NK cells are important immune effectors for preventing microbial invasion and dissemination, through natural cytotoxicity and cytokine secretion. Bacillus anthracis spores can efficiently drive IFN-γ production by NK cells. The present study provides insights into the mechanisms of cytokine and cellular signaling that underlie the process of NK-cell activation by B. anthracis and the bacterial strategies to subvert and evade this response. Infection with non-toxigenic encapsulated B. anthracis induced recruitment of NK cells and macrophages into the mouse draining lymph node. Production of edema (ET) or lethal (LT) toxin during infection impaired this cellular recruitment. NK cell depletion led to accelerated systemic bacterial dissemination. IFN-γ production by NK cells in response to B. anthracis spores was: i) contact-dependent through RAE-1-NKG2D interaction with macrophages; ii) IL-12, IL-18, and IL-15-dependent, where IL-12 played a key role and regulated both NK cell and macrophage activation; and iii) required IL-18 for only an initial short time window. B. anthracis toxins subverted both NK cell essential functions. ET and LT disrupted IFN-γ production through different mechanisms. LT acted both on macrophages and NK cells, whereas ET mainly affected macrophages and did not alter NK cell capacity of IFN-γ secretion. In contrast, ET and LT inhibited the natural cytotoxicity function of NK cells, both in vitro and in vivo. The subverting action of ET thus led to dissociation in NK cell function and blocked natural cytotoxicity without affecting IFN-γ secretion. The high efficiency of this process stresses the impact that this toxin may exert in anthrax pathogenesis, and highlights a potential usefulness for controlling excessive cytotoxic responses in immunopathological diseases. Our findings therefore exemplify the delicate balance between bacterial stimulation and evasion strategies. This highlights the potential implication of the crosstalk between host innate defences and B. anthracis in initial anthrax control mechanisms. NK cells are important immune effectors that perform a surveillance task and react to transformed, stressed, and virally infected cells. They represent a first-line defence against cancer and pathogen invasion. Different pathogens trigger distinct NK-cell activation pathways. The Bacillus anthracis spore is the highly resistant form that enters the host and provokes anthrax. This microbe kills through a combination of acute bacterial infection and devastating toxemia. In the present study, we characterise the crosstalk between NK cells and spores, as well as the strategies used by B. anthracis to evade initial control mechanisms and impact anthrax pathogenesis. Our findings exemplify the spores' property to efficiently drive a high production of IFN-γ by NK cells, as well as the complex pathways used for activation which require both cytokine and cellular signaling. B. anthracis subverts this response through its toxins by paralysing essential NK cell functions. Furthermore, edema toxin from B. anthracis blocks natural cytotoxicity without affecting IFN-γ secretion. The CyaA toxin of Bordetella pertussis possesses the same enzymatic activity and has a similar effect. The high efficiency of these toxins in blocking cytotoxicity in vivo implies possible exploitation of their subverting activity to modulate excessive cytotoxic responses in immunopathological diseases.
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MESH Headings
- Animals
- Bacillus anthracis/immunology
- Bacterial Toxins/pharmacology
- Cells, Cultured
- Female
- Homeostasis/drug effects
- Homeostasis/immunology
- Immunity, Cellular/drug effects
- Immunity, Cellular/immunology
- Killer Cells, Natural/drug effects
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Macrophage Activation/drug effects
- Macrophage Activation/immunology
- Macrophages/drug effects
- Macrophages/immunology
- Macrophages/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Receptor Cross-Talk/drug effects
- Receptor Cross-Talk/immunology
- Spores, Bacterial/immunology
- Spores, Bacterial/physiology
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Affiliation(s)
- Maria Klezovich-Bénard
- Laboratoire Pathogénie et Toxi-Infections Bactériennes, Institut Pasteur, Paris, France
- CNRS URA 2172, Paris, France
| | - Jean-Philippe Corre
- Laboratoire Pathogénie et Toxi-Infections Bactériennes, Institut Pasteur, Paris, France
- CNRS URA 2172, Paris, France
| | | | - Daniel Fiole
- Unité Interactions Hôte-Agents Pathogènes, Département de Microbiologie, Institut de Recherche Biomédicale des Armées, La Tronche, France
- Laboratoire Interdisciplinaire de Physique, UMR 5588 CNRS/Université Joseph Fourier, St-Martin-d'Hères, France
| | - Nick Burjek
- Laboratoire Pathogénie et Toxi-Infections Bactériennes, Institut Pasteur, Paris, France
- CNRS URA 2172, Paris, France
| | - Jean-Nicolas Tournier
- Unité Interactions Hôte-Agents Pathogènes, Département de Microbiologie, Institut de Recherche Biomédicale des Armées, La Tronche, France
- École du Val-de-Grâce, Paris, France
| | - Pierre L. Goossens
- Laboratoire Pathogénie et Toxi-Infections Bactériennes, Institut Pasteur, Paris, France
- CNRS URA 2172, Paris, France
- * E-mail:
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16
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Brzoza-Lewis KL, Hoth JJ, Hiltbold EM. Type I interferon signaling regulates the composition of inflammatory infiltrates upon infection with Listeria monocytogenes. Cell Immunol 2011; 273:41-51. [PMID: 22212606 DOI: 10.1016/j.cellimm.2011.11.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 11/01/2011] [Accepted: 11/20/2011] [Indexed: 12/24/2022]
Abstract
Type I IFN is key to the immune response to viral pathogens, however its role in bacterial infections is less well understood. Mice lacking the type I IFN receptor (IFNAR-/-) demonstrate enhanced resistance to infection with Listeriamonocytogenes. We have now determined that following infection with Listeria, the composition of innate cells recruited to the peritoneal cavity of IFNAR-/- mice reflects an increase in the frequency of neutrophils and a decrease in monocyte frequency compared to WT controls. These differences in inflammatory infiltrates could not be attributed to distinct bone marrow composition prior to infection or to level of apoptosis. We also observed no differences in neutrophil oxidative burst. However, blocking CXCR2 prevented enhanced neutrophil influx and hampered bacterial clearance. Taken together, these studies highlight a novel mechanism by which type I interferon signaling regulates the immune response to Listeria, through negative regulation of chemokines driving neutrophil recruitment.
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Affiliation(s)
- Kristina L Brzoza-Lewis
- Department of Microbiology and Immunology, Wake Forest University, School of Medicine, Winston-Salem, NC 27157, United States
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17
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de Almeida LA, Carvalho NB, Oliveira FS, Lacerda TLS, Vasconcelos AC, Nogueira L, Bafica A, Silva AM, Oliveira SC. MyD88 and STING signaling pathways are required for IRF3-mediated IFN-β induction in response to Brucella abortus infection. PLoS One 2011; 6:e23135. [PMID: 21829705 PMCID: PMC3149075 DOI: 10.1371/journal.pone.0023135] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 07/07/2011] [Indexed: 12/25/2022] Open
Abstract
Type I interferons (IFNs) are cytokines that orchestrate diverse immune responses to viral and bacterial infections. Although typically considered to be most important molecules in response to viruses, type I IFNs are also induced by most, if not all, bacterial pathogens. In this study, we addressed the role of type I IFN signaling during Brucella abortus infection, a facultative intracellular bacterial pathogen that causes abortion in domestic animals and undulant fever in humans. Herein, we have shown that B. abortus induced IFN-β in macrophages and splenocytes. Further, IFN-β induction by Brucella was mediated by IRF3 signaling pathway and activates IFN-stimulated genes via STAT1 phosphorylation. In addition, IFN-β expression induced by Brucella is independent of TLRs and TRIF signaling but MyD88-dependent, a pathway not yet described for Gram-negative bacteria. Furthermore, we have identified Brucella DNA as the major bacterial component to induce IFN-β and our study revealed that this molecule operates through a mechanism dependent on RNA polymerase III to be sensed probably by an unknown receptor via the adaptor molecule STING. Finally, we have demonstrated that IFN-αβR KO mice are more resistant to infection suggesting that type I IFN signaling is detrimental to host control of Brucella. This resistance phenotype is accompanied by increased IFN-γ and NO production by IFN-αβR KO spleen cells and reduced apoptosis.
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Affiliation(s)
- Leonardo A. de Almeida
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte-Minas Gerais, Brazil
| | - Natalia B. Carvalho
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte-Minas Gerais, Brazil
| | - Fernanda S. Oliveira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte-Minas Gerais, Brazil
| | - Thais L. S. Lacerda
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte-Minas Gerais, Brazil
| | - Anilton C. Vasconcelos
- Department of Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte-Minas Gerais, Brazil
| | - Lucas Nogueira
- Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina, Florianopolis-Santa Catarina, Brazil
| | - Andre Bafica
- Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina, Florianopolis-Santa Catarina, Brazil
| | - Aristóbolo M. Silva
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte-Minas Gerais, Brazil
| | - Sergio C. Oliveira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte-Minas Gerais, Brazil
- * E-mail:
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18
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Kobayashi H, Nolan A, Naveed B, Hoshino Y, Segal LN, Fujita Y, Rom WN, Weiden MD. Neutrophils activate alveolar macrophages by producing caspase-6-mediated cleavage of IL-1 receptor-associated kinase-M. THE JOURNAL OF IMMUNOLOGY 2010; 186:403-10. [PMID: 21098228 DOI: 10.4049/jimmunol.1001906] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Alveolar macrophages (AMs) are exposed to respirable microbial particles. Similar to phagocytes in the gastrointestinal tract, AMs can suppress inflammation after exposure to nonpathogenic organisms. IL-1R-associated kinase-M (IRAK-M) is one inhibitor of innate immunity, normally suppressing pulmonary inflammation. During pneumonia, polymorphonuclear neutrophils (PMNs) are recruited by chemotactic factors released by AMs to produce an intense inflammation. We report that intact IRAK-M is strongly expressed in resting human AMs but is cleaved in patients with pneumonia via PMN-mediated induction of caspase-6 (CASP-6) activity. PMN contact is necessary and PMN membranes are sufficient for CASP-6 induction in macrophages. PMNs fail to induce TNF-α fully in macrophages expressing CASP-6 cleavage-resistant IRAK-M. Without CASP-6 expression, PMN stimulation fails to cleave IRAK-M, degrade IκBα, or induce TNF-α. CASP-6(-/-) mice subjected to cecal ligation and puncture have impaired TNF-α production in the lung and decreased mortality. LPS did not induce or require CASP-6 activity demonstrating that TLR2/4 signaling is independent from the CASP-6 regulated pathway. These data define a central role for CASP-6 in PMN-driven macrophage activation and identify IRAK-M as an important target for CASP-6. PMNs de-repress AMs via CASP-6-mediated IRAK-M cleavage. This regulatory system will blunt lung inflammation unless PMNs infiltrate the alveolar spaces.
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Affiliation(s)
- Hiroshi Kobayashi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
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19
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Crawford MA, Burdick MD, Glomski IJ, Boyer AE, Barr JR, Mehrad B, Strieter RM, Hughes MA. Interferon-inducible CXC chemokines directly contribute to host defense against inhalational anthrax in a murine model of infection. PLoS Pathog 2010; 6:e1001199. [PMID: 21124994 PMCID: PMC2987825 DOI: 10.1371/journal.ppat.1001199] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 10/18/2010] [Indexed: 12/29/2022] Open
Abstract
Chemokines have been found to exert direct, defensin-like antimicrobial activity in vitro, suggesting that, in addition to orchestrating cellular accumulation and activation, chemokines may contribute directly to the innate host response against infection. No observations have been made, however, demonstrating direct chemokine-mediated promotion of host defense in vivo. Here, we show that the murine interferon-inducible CXC chemokines CXCL9, CXCL10, and CXCL11 each exert direct antimicrobial effects in vitro against Bacillus anthracis Sterne strain spores and bacilli including disruptions in spore germination and marked reductions in spore and bacilli viability as assessed using CFU determination and a fluorometric assay of metabolic activity. Similar chemokine-mediated antimicrobial activity was also observed against fully virulent Ames strain spores and encapsulated bacilli. Moreover, antibody-mediated neutralization of these CXC chemokines in vivo was found to significantly increase host susceptibility to pulmonary B. anthracis infection in a murine model of inhalational anthrax with disease progression characterized by systemic bacterial dissemination, toxemia, and host death. Neutralization of the shared chemokine receptor CXCR3, responsible for mediating cellular recruitment in response to CXCL9, CXCL10, and CXCL11, was not found to increase host susceptibility to inhalational anthrax. Taken together, our data demonstrate a novel, receptor-independent antimicrobial role for the interferon-inducible CXC chemokines in pulmonary innate immunity in vivo. These data also support an immunomodulatory approach for effectively treating and/or preventing pulmonary B. anthracis infection, as well as infections caused by pathogenic and potentially, multi-drug resistant bacteria including other spore-forming organisms. Innate immunity is critical to host defense and plays a central role in protecting the lungs from respiratory pathogens. Among the mediators important in the innate host response to pulmonary infection are chemokines, proteins originally described for their ability to regulate immune cell trafficking during an inflammatory response. More recently, chemokines have been found to exert direct antimicrobial activity against a broad range of bacteria and fungi in vitro. While these observations suggest chemokines may contribute to host defense by killing microorganisms at local sites of infection through activities not associated with cellular chemokine receptors, the biological relevance of direct chemokine-mediated antimicrobial activity in vivo has not been established. Here we show that the murine chemokines CXCL9, CXCL10, and CXCL11 exert direct antimicrobial effects against B. anthracis in vitro and that neutralization of these CXC chemokines, but not their shared receptor CXCR3, increases host susceptibility to pulmonary B. anthracis infection in vivo. These data provide unique insight into the host mediators important in host-pathogen interaction and pathogenesis of disease and support the emerging concept that host chemokines mediate efficient, pleiotropic roles that include receptor-independent promotion of host defense in vivo.
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Affiliation(s)
- Matthew A. Crawford
- Department of Medicine, Division of Infectious Diseases, University of Virginia, Charlottesville, Virginia, United States of America
| | - Marie D. Burdick
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Ian J. Glomski
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Anne E. Boyer
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - John R. Barr
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Borna Mehrad
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Robert M. Strieter
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Molly A. Hughes
- Department of Medicine, Division of Infectious Diseases, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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20
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Abstract
Although the role of type I interferon (IFN) in the protection against viral infections has been known and studied for decades, its role in other immunologically relevant scenarios, including bacterial infections, shock, autoimmunity, and cancer, is less well defined and potentially much more complicated.
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Affiliation(s)
- Giorgio Trinchieri
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
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21
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Conidia but not yeast cells of the fungal pathogen Histoplasma capsulatum trigger a type I interferon innate immune response in murine macrophages. Infect Immun 2010; 78:3871-82. [PMID: 20605974 DOI: 10.1128/iai.00204-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Histoplasma capsulatum is the most common cause of fungal respiratory infections and can lead to progressive disseminated infections, particularly in immunocompromised patients. Infection occurs upon inhalation of the aerosolized spores, known as conidia. Once inside the host, conidia are phagocytosed by alveolar macrophages. The conidia subsequently germinate and produce a budding yeast-like form that colonizes host macrophages and can disseminate throughout host organs and tissues. Even though conidia are the predominant infectious particle for H. capsulatum and are the first cell type encountered by the host during infection, very little is known at a molecular level about conidia or about their interaction with cells of the host immune system. We examined the interaction between conidia and host cells in a murine bone-marrow-derived macrophage model of infection. We used whole-genome expression profiling and quantitative reverse transcription-PCR (qRT-PCR) to monitor the macrophage signaling pathways that are modulated during infection with conidia. Our analysis revealed that type I interferon (IFN)-responsive genes and the beta type I IFN (IFN-beta) were induced in macrophages during infection with H. capsulatum conidia but not H. capsulatum yeast cells. Further analysis revealed that the type I IFN signature induced in macrophages in response to conidia is independent of Toll-like receptor (TLR) signaling and the cytosolic RNA sensor MAVS but is dependent on the transcription factor interferon regulatory factor 3 (IRF3). Interestingly, H. capsulatum growth was restricted in mice lacking the type I IFN receptor, indicating that an intact host type I IFN response is required for full virulence of H. capsulatum in mice.
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22
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Wu W, Mehta H, Chakrabarty K, Booth JL, Duggan ES, Patel KB, Ballard JD, Coggeshall KM, Metcalf JP. Resistance of human alveolar macrophages to Bacillus anthracis lethal toxin. THE JOURNAL OF IMMUNOLOGY 2009; 183:5799-806. [PMID: 19812208 DOI: 10.4049/jimmunol.0803406] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The etiologic agent of inhalational anthrax, Bacillus anthracis, produces virulence toxins that are important in the disease pathogenesis. Current studies suggest that mouse and human macrophages are susceptible to immunosuppressive effects of one of the virulence toxins, lethal toxin (LT). Thus a paradigm has emerged that holds that the alveolar macrophage (AM) does not play a significant role in the innate immune response to B. anthracis or defend against the pathogen as it is disabled by LT. This is inconsistent with animal models and autopsy studies that show minimal disease at the alveolar surface. We examined whether AM are immunosuppressed by LT. We found that human AM were relatively resistant to LT-mediated innate immune cytokine suppression, MEK cleavage, and induction of apoptosis as compared with mouse RAW 264.7 macrophages. Mouse AM and murine bone marrow-derived macrophages were also relatively resistant to LT-mediated apoptosis despite intermediate sensitivity to MEK cleavage. The binding component of LT, protective Ag, does not attach to human AM, although it did bind to mouse AM, murine bone marrow-derived macrophages, and RAW 264.7 macrophages. Human AM do not produce significant amounts of the protective Ag receptor anthrax toxin receptor 1 (TEM8/ANTXR1) and anthrax toxin receptor 2 (CMG2/ANTXR2). Thus, mature and differentiated AM are relatively resistant to the effects of LT as compared with mouse RAW 264.7 macrophages. AM resistance to LT may enhance clearance of the pathogen from the alveolar surface and explain why this surface is relatively free of B. anthracis in animal models and autopsy studies.
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Affiliation(s)
- Wenxin Wu
- Pulmonary and Critical Care Division, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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23
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NOD2, RIP2 and IRF5 play a critical role in the type I interferon response to Mycobacterium tuberculosis. PLoS Pathog 2009; 5:e1000500. [PMID: 19578435 PMCID: PMC2698121 DOI: 10.1371/journal.ppat.1000500] [Citation(s) in RCA: 213] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 06/05/2009] [Indexed: 01/01/2023] Open
Abstract
While the recognition of microbial infection often occurs at the cell surface via Toll-like receptors, the cytosol of the cell is also under surveillance for microbial products that breach the cell membrane. An important outcome of cytosolic recognition is the induction of IFNalpha and IFNbeta, which are critical mediators of immunity against both bacteria and viruses. Like many intracellular pathogens, a significant fraction of the transcriptional response to Mycobacterium tuberculosis infection depends on these type I interferons, but the recognition pathways responsible remain elusive. In this work, we demonstrate that intraphagosomal M. tuberculosis stimulates the cytosolic Nod2 pathway that responds to bacterial peptidoglycan, and this event requires membrane damage that is actively inflicted by the bacterium. Unexpectedly, this recognition triggers the expression of type I interferons in a Tbk1- and Irf5-dependent manner. This response is only partially impaired by the loss of Irf3 and therefore, differs fundamentally from those stimulated by bacterial DNA, which depend entirely on this transcription factor. This difference appears to result from the unusual peptidoglycan produced by mycobacteria, which we show is a uniquely potent agonist of the Nod2/Rip2/Irf5 pathway. Thus, the Nod2 system is specialized to recognize bacteria that actively perturb host membranes and is remarkably sensitive to mycobacteria, perhaps reflecting the strong evolutionary pressure exerted by these pathogens on the mammalian immune system.
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24
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Walberg K, Baron S, Poast J, Schwartz B, Izotova L, Pestka S, Peterson JW. Interferon protects mice against inhalation anthrax. J Interferon Cytokine Res 2009; 28:597-601. [PMID: 18778201 DOI: 10.1089/jir.2007.0143] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Interferons (IFNs) play a role in innate immunity during many viral, bacterial, and protozoal infections. With the increasing threat of bioterrorist attacks with Bacillus anthracis, its high lethality, and the limited effectiveness of antibiotics, alternative treatments are being studied. Antibodies to protective antigen (PA) are promising, as is IFN. During many bacterial infections, production of and protection by IFNs has been reported, including B. anthracis in vitro. In vivo, we find that (1) the type I IFN inducer, Poly-ICLC, strongly and rapidly protects mice; (2) the protection is IFN-mediated since recombinant murine IFN-beta can protect, and protection by Poly-ICLC is abrogated in IFN type I receptor knockout mice. The greatest protection by Poly-ICLC was conferred by intranasal treatment. A delay in death was observed with the intramuscular route alone, but was not significant. Together, the results suggest the IFN defense could protect mice, up to 60%, against lethal inhalational anthrax, and thus have important medical implications for therapy of human anthrax.
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Affiliation(s)
- Kristin Walberg
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555-1070, USA
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25
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Antimicrobial effects of interferon-inducible CXC chemokines against Bacillus anthracis spores and bacilli. Infect Immun 2009; 77:1664-78. [PMID: 19179419 DOI: 10.1128/iai.01208-08] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Based on previous studies showing that host chemokines exert antimicrobial activities against bacteria, we sought to determine whether the interferon-inducible Glu-Leu-Arg-negative CXC chemokines CXCL9, CXCL10, and CXCL11 exhibit antimicrobial activities against Bacillus anthracis. In vitro analysis demonstrated that all three CXC chemokines exerted direct antimicrobial effects against B. anthracis spores and bacilli including marked reductions in spore and bacillus viability as determined using a fluorometric assay of bacterial viability and CFU determinations. Electron microscopy studies revealed that CXCL10-treated spores failed to undergo germination as judged by an absence of cytological changes in spore structure that occur during the process of germination. Immunogold labeling of CXCL10-treated spores demonstrated that the chemokine was located internal to the exosporium in association primarily with the spore coat and its interface with the cortex. To begin examining the potential biological relevance of chemokine-mediated antimicrobial activity, we used a murine model of inhalational anthrax. Upon spore challenge, the lungs of C57BL/6 mice (resistant to inhalational B. anthracis infection) had significantly higher levels of CXCL9, CXCL10, and CXCL11 than did the lungs of A/J mice (highly susceptible to infection). Increased CXC chemokine levels were associated with significantly reduced levels of spore germination within the lungs as determined by in vivo imaging. Taken together, our data demonstrate a novel antimicrobial role for host chemokines against B. anthracis that provides unique insight into host defense against inhalational anthrax; these data also support the notion for an innovative approach in treating B. anthracis infection as well as infections caused by other spore-forming organisms.
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Qiu H, Fan Y, Joyee AG, Wang S, Han X, Bai H, Jiao L, Van Rooijen N, Yang X. Type I IFNs Enhance Susceptibility toChlamydia muridarumLung Infection by Enhancing Apoptosis of Local Macrophages. THE JOURNAL OF IMMUNOLOGY 2008; 181:2092-102. [DOI: 10.4049/jimmunol.181.3.2092] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Passalacqua KD, Bergman NH. Bacillus anthracis: interactions with the host and establishment of inhalational anthrax. Future Microbiol 2007; 1:397-415. [PMID: 17661631 DOI: 10.2217/17460913.1.4.397] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Due to its potential as a bioweapon, Bacillus anthracis has received a great deal of attention in recent years, and a significant effort has been devoted to understanding how this organism causes anthrax. There has been a particular focus on the inhalational form of the disease, and studies over the past several years have painted an increasingly complex picture of how B. anthracis enters the mammalian host, survives the host's defense mechanisms, disseminates throughout the body and causes death. This article reviews recent advances in these areas, with a focus on how the bacterium interacts with its host in establishing infection and causing anthrax.
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Affiliation(s)
- Karla D Passalacqua
- University of Michigan Medical School, Department of Microbiology & Immunology, Ann Arbor, MI 48109, USA.
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Gold JA, Hoshino Y, Jones MB, Hoshino S, Nolan A, Weiden MD. Exogenous interferon-alpha and interferon-gamma increase lethality of murine inhalational anthrax. PLoS One 2007; 2:e736. [PMID: 17710136 PMCID: PMC1937023 DOI: 10.1371/journal.pone.0000736] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 07/16/2007] [Indexed: 01/14/2023] Open
Abstract
Background Bacillus anthracis, the etiologic agent of inhalational anthrax, is a facultative intracellular pathogen. Despite appropriate antimicrobial therapy, the mortality from inhalational anthrax approaches 45%, underscoring the need for better adjuvant therapies. The variable latency between exposure and development of disease suggests an important role for the host's innate immune response. Type I and Type II Interferons (IFN) are prominent members of the host innate immune response and are required for control of intracellular pathogens. We have previously described a protective role for exogenous Type I and Type II IFNs in attenuating intracellular B.anthracis germination and macrophage cell death in vitro. Methodology and Principal Findings We sought to extend these findings in an in vivo model of inhalational anthrax, utilizing the Sterne strain (34F2) of B.anthracis. Mice devoid of STAT1, a component of IFN-α and IFN-γ signaling, had a trend towards increased mortality, bacterial germination and extrapulmonary spread of B.anthracis at 24 hrs. This was associated with impaired IL-6, IL-10 and IL-12 production. However, administration of exogenous IFN-γ, and to a lesser extent IFN-α, at the time of infection, markedly increased lethality. While IFNs were able to reduce the fraction of germinated spores within the lung, they increased both the local and systemic inflammatory response manifest by increases in IL-12 and reductions in IL-10. This was associated with an increase in extrapulmonary dissemination. The mechanism of IFN mediated inflammation appears to be in part due to STAT1 independent signaling. Conclusions In conclusion, while endogenous IFNs are essential for control of B.anthracis germination and lethality, administration of exogenous IFNs appear to increase the local inflammatory response, thereby increasing mortality.
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Affiliation(s)
- Jeffrey A Gold
- Division of Pulmonary and Critical Care Medicine, Oregon Health and Sciences University, Portland, Oregon, United States of America.
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Glomski IJ, Corre JP, Mock M, Goossens PL. Cutting Edge: IFN-gamma-producing CD4 T lymphocytes mediate spore-induced immunity to capsulated Bacillus anthracis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2007; 178:2646-50. [PMID: 17312104 DOI: 10.4049/jimmunol.178.5.2646] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Virulent strains of Bacillus anthracis produce immunomodulating toxins and an antiphagocytic capsule. The toxin component-protective Ag is a key target of the antianthrax immune response that induces production of toxin-neutralizing Abs. Coimmunization with spores enhances the antitoxin vaccine, and inactivated spores alone confer measurable protection. We aimed to identify the mechanisms of protection induced in inactivated-spore immunized mice that function independently of the toxin/antitoxin vaccine system. This goal was addressed with humoral and CD4 T lymphocyte transfer, in vivo depletion of CD4 T lymphocytes and IFN-gamma, and Ab-deficient (muMT(-/-)) or IFN-gamma-insensitive (IFN-gammaR(-/-)) mice. We found that humoral immunity did not protect from nontoxinogenic capsulated bacteria, whereas a cellular immune response by IFN-gamma-producing CD4 T lymphocytes protected mice. These results are the first evidence of protective cellular immunity against capsulated B. anthracis and suggest that future antianthrax vaccines should strive to augment cellular adaptive immunity.
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Affiliation(s)
- Ian Justin Glomski
- Unité des Toxines et Pathogénie Bactérienne, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
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Glomski IJ, Fritz JH, Keppler SJ, Balloy V, Chignard M, Mock M, Goossens PL. Murine splenocytes produce inflammatory cytokines in a MyD88-dependent response to Bacillus anthracis spores. Cell Microbiol 2007; 9:502-13. [PMID: 16978234 DOI: 10.1111/j.1462-5822.2006.00806.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacillus anthracis is a sporulating Gram-positive bacterium that causes the disease anthrax. The highly stable spore is the infectious form of the bacterium that first interacts with the prospective host, and thus the interaction between the host and spore is vital to the development of disease. We focused our study on the response of murine splenocytes to the B. anthracis spore by using paraformaldehyde-inactivated spores (FIS), a treatment that prevents germination and production of products associated with vegetative bacilli. We found that murine splenocytes produce IL-12 and IFN-gamma in response to FIS. The IL-12 was secreted by CD11b cells, which functioned to induce the production of IFN-gamma by CD49b (DX5) NK cells. The production of these cytokines by splenocytes was not dependent on TLR2, TLR4, TLR9, Nod1, or Nod2; however, it was dependent on the signalling adapter protein MyD88. Unlike splenocytes, Nod1- and Nod2-transfected HEK cells were activated by FIS. Both IL-12 and IFN-gamma secretion were inhibited by treatment with B. anthracis lethal toxin. These observations suggest that the innate immune system recognizes spores with a MyD88-dependent receptor (or receptors) and responds by secreting inflammatory cytokines, which may ultimately aid in resisting infection.
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Affiliation(s)
- Ian J Glomski
- Institut Pasteur, Unité des Toxines et Pathogénie Bactérienne, Paris, F-75015, France
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Sabet M, Cottam HB, Guiney DG. Modulation of cytokine production and enhancement of cell viability by TLR7 and TLR9 ligands during anthrax infection of macrophages. ACTA ACUST UNITED AC 2006; 47:369-79. [PMID: 16872373 DOI: 10.1111/j.1574-695x.2006.00096.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Inhalation of Bacillus anthracis, a bioterrorism agent, results in a high mortality rate despite appropriate antibiotic therapy. Macrophages appear to be a key factor in B. anthracis pathogenesis. The burst of pro-inflammatory cytokines from macrophages could be a major cause of death in anthrax. However, preactivation of Toll-like receptors (TLRs) could modify the host response. TLR ligands stimulate the release of activating cytokines but may also down-modulate the subsequent deleterious cytokine response to pathogens. We developed a cell culture model to measure macrophage responses to B. anthracis spores and bacilli. We found that germination from spores to bacilli produced a substantial stimulus for the secretion of the cytokines IL-6, TNF-alpha, IL-10, and IL-12 p40. Our studies showed that pretreatment of mouse macrophages with the TLR9 ligand ISS-1018, or the TLR7 ligands R-848 and IT-37, results in a substantial decrease in the subsequent secretion of IL-6 and TNF-alpha in response to B. anthracis infection of macrophages. Furthermore, the TLR7 and TLR9 ligands significantly decreased anthrax-induced cytotoxicity in the macrophages. These findings suggest that TLR ligands may contribute to the enhancement of innate immunity in B. anthracis infection by suppressing potentially deleterious pro-inflammatory cytokine responses and by improving macrophage viability.
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Affiliation(s)
- Mojgan Sabet
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0640, USA.
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Brown CR, Blaho VA, Fritsche KL, Loiacono CM. Stat1 deficiency exacerbates carditis but not arthritis during experimental lyme borreliosis. J Interferon Cytokine Res 2006; 26:390-9. [PMID: 16734559 DOI: 10.1089/jir.2006.26.390] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Activation of the transcription factor Stat1 by interferon-gamma (IFN-gamma) is an important step in the development of antimicrobial effector mechanisms against many bacterial pathogens. Susceptibility to murine Lyme arthritis has been correlated with the production of several proinflammatory cytokines, especially IFN-gamma. To determine the role of IFN-mediated effector mechanisms in the development of Lyme borreliosis, we infected Stat1-deficient mice on both resistant (DBA), and susceptible (C3H) genetic backgrounds. Arthritis in Stat1(/) mice was similar to that of wild-type controls in both mouse strains. Spirochete loads in tissues were also unchanged in Stat1(/) mice. C3H Stat1(/) mice exhibited increased inflammation in the heart, whereas carditis was unchanged in DBA Stat1(/) mice. These results demonstrate that inhibition of macrophage activation and responses to IFN-gamma-mediated signaling do not alter the arthritis resistance or susceptibility phenotype; however, they do affect the severity of carditis in susceptible mouse strains.
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Affiliation(s)
- Charles R Brown
- Department of Molecular Microbiology, Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA.
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Ulett GC, Adderson EE. Regulation of Apoptosis by Gram-Positive Bacteria: Mechanistic Diversity and Consequences for Immunity. ACTA ACUST UNITED AC 2006; 2:119-141. [PMID: 19081777 DOI: 10.2174/157339506776843033] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Apoptosis, or programmed cell death (PCD), is an important physiological mechanism, through which the human immune system regulates homeostasis and responds to diverse forms of cellular damage. PCD may also be involved in immune counteraction to microbial infection. Over the past decade, the amount of research on bacteria-induced PCD has grown tremendously, and the implications of this mechanism on immunity are being elucidated. Some pathogenic bacteria actively trigger the suicide response in critical lineages of leukocytes that orchestrate both the innate and adaptive immune responses; other bacteria proactively prevent PCD to benefit their own survival and persistence. Currently, the microbial virulence factors, which represent the keys to unlocking the suicide response in host cells, are a primary focus of this field. In this review, we discuss these bacterial "apoptosis regulatory molecules" and the apoptotic events they either trigger or prevent, the host target cells of this regulatory activity, and the possible ramifications for immunity to infection. Gram-positive pathogens including Staphylococcus, Streptococcus, Bacillus, Listeria, and Clostridia species are discussed as important agents of human infection that modulate PCD pathways in eukaryotic cells.
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Affiliation(s)
- Glen C Ulett
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105-2794, USA
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Banks DJ, Barnajian M, Maldonado-Arocho FJ, Sanchez AM, Bradley KA. Anthrax toxin receptor 2 mediates Bacillus anthracis killing of macrophages following spore challenge. Cell Microbiol 2005; 7:1173-85. [PMID: 16008584 DOI: 10.1111/j.1462-5822.2005.00545.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Initiation of inhalation anthrax is believed to involve phagocytosis of Bacillus anthracis spores by alveolar macrophages, followed by spore germination within the phagolysosome. In order to establish a systemic infection, it is predicted that bacilli then escape from the macrophage and replicate extracellularly. Mechanisms utilized by B. anthracis to escape from the macrophage are not well characterized, but a role for anthrax toxin has been proposed. Here we report the isolation of an anthrax toxin-resistant cell line (R3D) following chemical mutagenesis of toxin-sensitive RAW 264.7 murine macrophage cells. Both R3D and RAW 264.7 cells phagocytize spores of a B. anthracis Sterne strain. However, RAW 264.7 cells are killed following spore challenge, whereas R3D cells survive. Resistance to toxin and spore challenge correlates with loss of expression of anthrax toxin receptor 2 (ANTXR2/CMG-2). When R3D cells are complemented with cDNA encoding either murine ANTXR2 or human anthrax toxin receptor 1 (ANTXR1/TEM-8), toxin and spore challenge susceptibility are restored, indicating that over-expression of either ANTXR can confer susceptibility to anthrax spore challenge. Taken together, these results indicate that anthrax toxin expression by the germinated spore enables B. anthracis killing of the macrophage from within.
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Affiliation(s)
- David J Banks
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
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Decker T, Müller M, Stockinger S. The Yin and Yang of type I interferon activity in bacterial infection. Nat Rev Immunol 2005; 5:675-87. [PMID: 16110316 DOI: 10.1038/nri1684] [Citation(s) in RCA: 359] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Interferons (IFNs) are cytokines that are important for immune responses, particularly to intracellular pathogens. They are divided into two structurally and functionally distinct types that interact with different cell-surface receptors. Classically, type I IFNs are potent antiviral immunoregulators, whereas the type II IFN enhances antibacterial immunity. However, as outlined here, type I IFNs are also produced in response to infection with other pathogens, and an increasing body of work shows that type I IFNs have an important role in the host response to bacterial infection. Strikingly, their activity can be either favourable or detrimental, and can influence various immune effector mechanisms.
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Affiliation(s)
- Thomas Decker
- Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Microbiology and Immunobiology, University of Vienna, Vienna, Austria.
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Abstract
For a long time, the family of type I interferons (IFN-alpha/beta) has received little attention outside the fields of virology and tumor immunology. In recent years, IFN-alpha/beta regained the interest of immunologists, due to the phenotypic and functional characterization of IFN-alpha/beta-producing cells, the definition of novel immunomodulatory functions and signaling pathways of IFN-alpha/beta, and the observation that IFN-alpha/beta not only exerts antiviral effects but is also relevant for the pathogenesis or control of certain bacterial and protozoan infections. This review summarizes the current knowledge on the production and function of IFN-alpha/beta during non-viral infections in vitro and in vivo.
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Affiliation(s)
- Christian Bogdan
- Institute of Medical Microbiology and Hygiene, Department of Microbiology and Hygiene, University of Freiburg, Freiburg, Germany.
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Bergman NH, Passalacqua KD, Gaspard R, Shetron-Rama LM, Quackenbush J, Hanna PC. Murine macrophage transcriptional responses to Bacillus anthracis infection and intoxication. Infect Immun 2005; 73:1069-80. [PMID: 15664951 PMCID: PMC547061 DOI: 10.1128/iai.73.2.1069-1080.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 10/12/2004] [Accepted: 10/29/2004] [Indexed: 12/17/2022] Open
Abstract
Interactions between Bacillus anthracis and host macrophages represent critical early events in anthrax pathogenesis, but their details are not clearly understood. Here we report the first genomewide characterization of the transcriptional changes within macrophages infected with B. anthracis and the identification of several hundred host genes that were differentially expressed during this intracellular stage of infection. These loci included both genes that are known to be regulated differentially in response to many other bacterial pathogens and those that appear to be differentially regulated in response to B. anthracis but not other bacterial species that have been tested. These data provide a transcriptional basis for a variety of physiological changes observed during infection, including the induction of apoptosis caused by the infecting bacteria. The expression patterns underlying B. anthracis-induced apoptosis led us to test further the importance of one very highly induced macrophage gene, that for ornithine decarboxylase. Our data show that this enzyme plays an important and previously unrecognized role in suppressing apoptosis in B. anthracis-infected cells. We have also characterized the transcriptional response to anthrax lethal toxin in activated macrophages and found that, following toxin treatment, many of the host inflammatory response pathways are dampened. These data provide insights into B. anthracis pathogenesis as well as potential leads for the development of new diagnostic and therapeutic options.
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Affiliation(s)
- Nicholas H Bergman
- Bioinformatics Program, and Department of Microbiology & Immunology, University of Michigan Medical School, 5641 Med Sci II, Ann Arbor, MI 48109-0620, USA
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Barth H, Aktories K, Popoff MR, Stiles BG. Binary bacterial toxins: biochemistry, biology, and applications of common Clostridium and Bacillus proteins. Microbiol Mol Biol Rev 2004; 68:373-402, table of contents. [PMID: 15353562 PMCID: PMC515256 DOI: 10.1128/mmbr.68.3.373-402.2004] [Citation(s) in RCA: 285] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Certain pathogenic species of Bacillus and Clostridium have developed unique methods for intoxicating cells that employ the classic enzymatic "A-B" paradigm for protein toxins. The binary toxins produced by B. anthracis, B. cereus, C. botulinum, C. difficile, C. perfringens, and C. spiroforme consist of components not physically associated in solution that are linked to various diseases in humans, animals, or insects. The "B" components are synthesized as precursors that are subsequently activated by serine-type proteases on the targeted cell surface and/or in solution. Following release of a 20-kDa N-terminal peptide, the activated "B" components form homoheptameric rings that subsequently dock with an "A" component(s) on the cell surface. By following an acidified endosomal route and translocation into the cytosol, "A" molecules disable a cell (and host organism) via disruption of the actin cytoskeleton, increasing intracellular levels of cyclic AMP, or inactivation of signaling pathways linked to mitogen-activated protein kinase kinases. Recently, B. anthracis has gleaned much notoriety as a biowarfare/bioterrorism agent, and of primary interest has been the edema and lethal toxins, their role in anthrax, as well as the development of efficacious vaccines and therapeutics targeting these virulence factors and ultimately B. anthracis. This review comprehensively surveys the literature and discusses the similarities, as well as distinct differences, between each Clostridium and Bacillus binary toxin in terms of their biochemistry, biology, genetics, structure, and applications in science and medicine. The information may foster future studies that aid novel vaccine and drug development, as well as a better understanding of a conserved intoxication process utilized by various gram-positive, spore-forming bacteria.
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Affiliation(s)
- Holger Barth
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie der Albert-Ludwigs-Universität Freiburg, Otto-Krayer-Haus, Albertstrasse 25, D-79104 Freiburg, Germany.
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