1
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Rehman S, Antonovic AK, McIntire IE, Zheng H, Cleaver L, Baczynska M, Adams CO, Portlock T, Richardson K, Shaw R, Oregioni A, Mastroianni G, Whittaker SBM, Kelly G, Lorenz CD, Fornili A, Cianciotto NP, Garnett JA. The Legionella collagen-like protein employs a distinct binding mechanism for the recognition of host glycosaminoglycans. Nat Commun 2024; 15:4912. [PMID: 38851738 PMCID: PMC11162425 DOI: 10.1038/s41467-024-49255-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 05/30/2024] [Indexed: 06/10/2024] Open
Abstract
Bacterial adhesion is a fundamental process which enables colonisation of niche environments and is key for infection. However, in Legionella pneumophila, the causative agent of Legionnaires' disease, these processes are not well understood. The Legionella collagen-like protein (Lcl) is an extracellular peripheral membrane protein that recognises sulphated glycosaminoglycans on the surface of eukaryotic cells, but also stimulates bacterial aggregation in response to divalent cations. Here we report the crystal structure of the Lcl C-terminal domain (Lcl-CTD) and present a model for intact Lcl. Our data reveal that Lcl-CTD forms an unusual trimer arrangement with a positively charged external surface and negatively charged solvent exposed internal cavity. Through molecular dynamics simulations, we show how the glycosaminoglycan chondroitin-4-sulphate associates with the Lcl-CTD surface via distinct binding modes. Our findings show that Lcl homologs are present across both the Pseudomonadota and Fibrobacterota-Chlorobiota-Bacteroidota phyla and suggest that Lcl may represent a versatile carbohydrate-binding mechanism.
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Affiliation(s)
- Saima Rehman
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Anna Katarina Antonovic
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Ian E McIntire
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Huaixin Zheng
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Leanne Cleaver
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Maria Baczynska
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
- Biological Physics & Soft Matter Research Group, Department of Physics, King's College London, London, UK
| | - Carlton O Adams
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Theo Portlock
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Katherine Richardson
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Rosie Shaw
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Alain Oregioni
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Giulia Mastroianni
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Sara B-M Whittaker
- School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Geoff Kelly
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Christian D Lorenz
- Biological Physics & Soft Matter Research Group, Department of Physics, King's College London, London, UK
| | - Arianna Fornili
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London, UK.
| | - Nicholas P Cianciotto
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - James A Garnett
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK.
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2
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Crépin A, Thiroux A, Alafaci A, Boukerb AM, Dufour I, Chrysanthou E, Bertaux J, Tahrioui A, Bazire A, Rodrigues S, Taupin L, Feuilloley M, Dufour A, Caillon J, Lesouhaitier O, Chevalier S, Berjeaud JM, Verdon J. Sensitivity of Legionella pneumophila to phthalates and their substitutes. Sci Rep 2023; 13:22145. [PMID: 38092873 PMCID: PMC10719263 DOI: 10.1038/s41598-023-49426-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 12/07/2023] [Indexed: 12/17/2023] Open
Abstract
Phthalates constitute a family of anthropogenic chemicals developed to be used in the manufacture of plastics, solvents, and personal care products. Their dispersion and accumulation in many environments can occur at all stages of their use (from synthesis to recycling). However, many phthalates together with other accumulated engineered chemicals have been shown to interfere with hormone activities. These compounds are also in close contact with microorganisms that are free-living, in biofilms or in microbiota, within multicellular organisms. Herein, the activity of several phthalates and their substitutes were investigated on the opportunistic pathogen Legionella pneumophila, an aquatic microbe that can infect humans. Beside showing the toxicity of some phthalates, data suggested that Acetyl tributyl citrate (ATBC) and DBP (Di-n-butyl phthalate) at environmental doses (i.e. 10-6 M and 10-8 M) can modulate Legionella behavior in terms of motility, biofilm formation and response to antibiotics. A dose of 10-6 M mostly induced adverse effects for the bacteria, in contrast to a dose of 10-8 M. No perturbation of virulence towards Acanthamoeba castellanii was recorded. These behavioral alterations suggest that L. pneumophila is able to sense ATBC and DBP, in a cross-talk that either mimics the response to a native ligand, or dysregulates its physiology.
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Affiliation(s)
- Alexandre Crépin
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France
| | - Audrey Thiroux
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France
| | - Aurélien Alafaci
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France
| | - Amine M Boukerb
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, UR4312, Université de Rouen Normandie, Normandie Université, Évreux, France
| | - Izelenn Dufour
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France
| | - Eirini Chrysanthou
- Department of Life Sciences and Systems Biology, University of Turin, 10100, Turin, Italy
- Cancer Genomics Lab, Fondazione Edo ed Elvo Tempia, 13900, Biella, Italy
| | - Joanne Bertaux
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France
| | - Ali Tahrioui
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, UR4312, Université de Rouen Normandie, Normandie Université, Évreux, France
| | - Alexis Bazire
- Laboratoire de Biotechnologie et Chimie Marines, Université Bretagne Sud, EMR CNRS 6076, IUEM, Lorient, France
| | - Sophie Rodrigues
- Laboratoire de Biotechnologie et Chimie Marines, Université Bretagne Sud, EMR CNRS 6076, IUEM, Lorient, France
| | - Laure Taupin
- Laboratoire de Biotechnologie et Chimie Marines, Université Bretagne Sud, EMR CNRS 6076, IUEM, Lorient, France
| | - Marc Feuilloley
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, UR4312, Université de Rouen Normandie, Normandie Université, Évreux, France
| | - Alain Dufour
- Laboratoire de Biotechnologie et Chimie Marines, Université Bretagne Sud, EMR CNRS 6076, IUEM, Lorient, France
| | - Jocelyne Caillon
- Faculté de Médecine, EA3826 Thérapeutiques Cliniques et Expérimentales des Infections, Université de Nantes, Nantes, France
| | - Olivier Lesouhaitier
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, UR4312, Université de Rouen Normandie, Normandie Université, Évreux, France
| | - Sylvie Chevalier
- Unité de recherche Communication Bactérienne et Stratégies Anti-infectieuses, UR4312, Université de Rouen Normandie, Normandie Université, Évreux, France
| | - Jean-Marc Berjeaud
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France
| | - Julien Verdon
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France.
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3
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Rehman S, Antonovic AK, McIntire IE, Zheng H, Cleaver L, Adams CO, Portlock T, Richardson K, Shaw R, Oregioni A, Mastroianni G, Whittaker SBM, Kelly G, Fornili A, Cianciotto NP, Garnett JA. The Legionella collagen-like protein employs a unique binding mechanism for the recognition of host glycosaminoglycans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.10.570962. [PMID: 38106198 PMCID: PMC10723406 DOI: 10.1101/2023.12.10.570962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Bacterial adhesion is a fundamental process which enables colonisation of niche environments and is key for infection. However, in Legionella pneumophila, the causative agent of Legionnaires' disease, these processes are not well understood. The Legionella collagen-like protein (Lcl) is an extracellular peripheral membrane protein that recognises sulphated glycosaminoglycans (GAGs) on the surface of eukaryotic cells, but also stimulates bacterial aggregation in response to divalent cations. Here we report the crystal structure of the Lcl C-terminal domain (Lcl-CTD) and present a model for intact Lcl. Our data reveal that Lcl-CTD forms an unusual dynamic trimer arrangement with a positively charged external surface and a negatively charged solvent exposed internal cavity. Through Molecular Dynamics (MD) simulations, we show how the GAG chondroitin-4-sulphate associates with the Lcl-CTD surface via unique binding modes. Our findings show that Lcl homologs are present across both the Pseudomonadota and Fibrobacterota-Chlorobiota-Bacteroidota phyla and suggest that Lcl may represent a versatile carbohydrate binding mechanism.
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Affiliation(s)
- Saima Rehman
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, UK
| | - Anna K. Antonovic
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Ian E. McIntire
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Huaixin Zheng
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Leanne Cleaver
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, UK
| | - Carlton O. Adams
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Theo Portlock
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, UK
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Katherine Richardson
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Rosie Shaw
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Alain Oregioni
- The Medical Research Council Biomedical NMR Centre, the Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Giulia Mastroianni
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Sara B-M. Whittaker
- School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Geoff Kelly
- The Medical Research Council Biomedical NMR Centre, the Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Arianna Fornili
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Nicholas P. Cianciotto
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - James A. Garnett
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, UK
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Iruegas R, Pfefferle K, Göttig S, Averhoff B, Ebersberger I. Feature architecture aware phylogenetic profiling indicates a functional diversification of type IVa pili in the nosocomial pathogen Acinetobacter baumannii. PLoS Genet 2023; 19:e1010646. [PMID: 37498819 PMCID: PMC10374093 DOI: 10.1371/journal.pgen.1010646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 06/06/2023] [Indexed: 07/29/2023] Open
Abstract
The Gram-negative bacterial pathogen Acinetobacter baumannii is a major cause of hospital-acquired opportunistic infections. The increasing spread of pan-drug resistant strains makes A. baumannii top-ranking among the ESKAPE pathogens for which novel routes of treatment are urgently needed. Comparative genomics approaches have successfully identified genetic changes coinciding with the emergence of pathogenicity in Acinetobacter. Genes that are prevalent both in pathogenic and a-pathogenic Acinetobacter species were not considered ignoring that virulence factors may emerge by the modification of evolutionarily old and widespread proteins. Here, we increased the resolution of comparative genomics analyses to also include lineage-specific changes in protein feature architectures. Using type IVa pili (T4aP) as an example, we show that three pilus components, among them the pilus tip adhesin ComC, vary in their Pfam domain annotation within the genus Acinetobacter. In most pathogenic Acinetobacter isolates, ComC displays a von Willebrand Factor type A domain harboring a finger-like protrusion, and we provide experimental evidence that this finger conveys virulence-related functions in A. baumannii. All three genes are part of an evolutionary cassette, which has been replaced at least twice during A. baumannii diversification. The resulting strain-specific differences in T4aP layout suggests differences in the way how individual strains interact with their host. Our study underpins the hypothesis that A. baumannii uses T4aP for host infection as it was shown previously for other pathogens. It also indicates that many more functional complexes may exist whose precise functions have been adjusted by modifying individual components on the domain level.
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Affiliation(s)
- Ruben Iruegas
- Applied Bioinformatics Group, Inst of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Katharina Pfefferle
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Stephan Göttig
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | - Beate Averhoff
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Ingo Ebersberger
- Applied Bioinformatics Group, Inst of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
- Senckenberg Biodiversity and Climate Research Centre (S-BIK-F), Frankfurt am Main, Germany
- LOEWE Centre for Translational Biodiversity Genomics (TBG), Frankfurt am Main, Germany
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5
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The Kingella kingae PilC1 MIDAS Motif Is Essential for Type IV Pilus Adhesive Activity and Twitching Motility. Infect Immun 2023; 91:e0033822. [PMID: 36537792 PMCID: PMC9872652 DOI: 10.1128/iai.00338-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Kingella kingae is an emerging pathogen that has recently been identified as a leading cause of osteoarticular infections in young children. Colonization with K. kingae is common, with approximately 10% of young children carrying this organism in the oropharynx at any given time. Adherence to epithelial cells represents the first step in K. kingae colonization of the oropharynx, a prerequisite for invasive disease. Type IV pili and the pilus-associated PilC1 and PilC2 proteins have been shown to mediate K. kingae adherence to epithelial cells, but the molecular mechanism of this adhesion has remained unknown. Metal ion-dependent adhesion site (MIDAS) motifs are commonly found in integrins, where they function to promote an adhesive interaction with a ligand. In this study, we identified a potential MIDAS motif in K. kingae PilC1 which we hypothesized was directly involved in mediating type IV pilus adhesive interactions. We found that the K. kingae PilC1 MIDAS motif was required for bacterial adherence to epithelial cell monolayers and extracellular matrix proteins and for twitching motility. Our results demonstrate that K. kingae has co-opted a eukaryotic adhesive motif for promoting adherence to host structures and facilitating colonization.
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6
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Scheithauer L, Karagöz MS, Mayer BE, Steinert M. Protein sociology of ProA, Mip and other secreted virulence factors at the Legionella pneumophila surface. Front Cell Infect Microbiol 2023; 13:1140688. [PMID: 36936764 PMCID: PMC10017501 DOI: 10.3389/fcimb.2023.1140688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/17/2023] [Indexed: 03/06/2023] Open
Abstract
The pathogenicity of L. pneumophila, the causative agent of Legionnaires' disease, depends on an arsenal of interacting proteins. Here we describe how surface-associated and secreted virulence factors of this pathogen interact with each other or target extra- and intracellular host proteins resulting in host cell manipulation and tissue colonization. Since progress of computational methods like AlphaFold, molecular dynamics simulation, and docking allows to predict, analyze and evaluate experimental proteomic and interactomic data, we describe how the combination of these approaches generated new insights into the multifaceted "protein sociology" of the zinc metalloprotease ProA and the peptidyl-prolyl cis/trans isomerase Mip (macrophage infectivity potentiator). Both virulence factors of L. pneumophila interact with numerous proteins including bacterial flagellin (FlaA) and host collagen, and play important roles in virulence regulation, host tissue degradation and immune evasion. The recent progress in protein-ligand analyses of virulence factors suggests that machine learning will also have a beneficial impact in early stages of drug discovery.
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Affiliation(s)
- Lina Scheithauer
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Mustafa Safa Karagöz
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Benjamin E. Mayer
- Computational Biology & Simulation, Technische Universität Darmstadt, Darmstadt, Germany
| | - Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
- *Correspondence: Michael Steinert,
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The Effect Citrox BCL on Legionella pneumophila Mechanisms of Biofilm Formation, Oxidative Stress and Virulence. Antioxidants (Basel) 2022; 11:antiox11112186. [DOI: 10.3390/antiox11112186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 10/31/2022] [Accepted: 11/01/2022] [Indexed: 11/09/2022] Open
Abstract
Legionella pneumophila is responsible for causing Legionnaires’ disease and Pontiac fever, also known as legionellosis. The aim of this study was to investigate the mechanistic effect of a mixture of natural antimicrobials (Citrox BCL) in preventing L. pneumophila biofilm formation and reducing its in vitro virulence. The minimum inhibitory concentrations were detected at 0.06%, and the MBC was established at 0.125%. Based on the growth curve profile, the sub-inhibitory concentration of 0.02% was further used to study the mechanistic implications in the absence of a cytotoxic effect on A549 cells. At 24 h post-infection, Citrox BCL reduced (p = 0.005) the intracellular growth of L. pneumophila when the A549 cells or the bacteria were pre-treated with 0.02% Citrox BCL. This result was replicated when Citrox BCL was added during the 24 h infection assay leading to a reduction in intracellular growth (p = 0.003). Herein we show that at the sub-inhibitory concentration of 0.02%, Citrox CBL lowers the ROS levels in infected A549 cells and causes a 45% reduction in L. pneumophila EPS production, a reduction associated with the decline in biofilm formation. Overall, our results corroborate the low c-di-GMP production with the decrease in biofilm formation and low EPS levels. The low EPS levels seemed to be caused by the downregulation of the tatB and tatC gene expressions. Moreover, inhibition of pvcA and pvcB gene expressions, leading to lower siderophore levels, suggests that Citrox BCL reduces the ability of L. pneumophila to sequester iron and reduce biofilm formation through iron starvation.
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Legionella pneumophila PPIase Mip Interacts with the Bacterial Proteins SspB, Lpc2061, and FlaA and Promotes Flagellation. Infect Immun 2022; 90:e0027622. [PMID: 36314784 PMCID: PMC9670971 DOI: 10.1128/iai.00276-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The peptidyl-prolyl-
cis/trans
-isomerase (PPIase) macrophage infectivity potentiator (Mip) contributes to the pathogenicity and fitness of
L. pneumophila
, the causative agent of Legionnaires’ disease. Here, we identified the stringent starvation protein SspB, hypothetical protein Lpc2061, and flagellin FlaA as bacterial interaction partners of Mip.
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Iliadi V, Staykova J, Iliadis S, Konstantinidou I, Sivykh P, Romanidou G, Vardikov DF, Cassimos D, Konstantinidis TG. Legionella pneumophila: The Journey from the Environment to the Blood. J Clin Med 2022; 11:jcm11206126. [PMID: 36294446 PMCID: PMC9605555 DOI: 10.3390/jcm11206126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/26/2022] [Accepted: 10/16/2022] [Indexed: 11/16/2022] Open
Abstract
An outbreak of a potentially fatal form of pneumonia in 1976 and in the annual convention of the American Legion was the first time that Legionella spp. was identified. Thereafter, the term Legionnaires’ disease (LD) was established. The infection in humans is transmitted by the inhalation of aerosols that contain the microorganisms that belong to the Legionellaceae family and the genus Legionella. The genus Legionella contains genetically heterogeneous species and serogroups. The Legionella pneumophila serogroup 1 (Lp1) is the most often detected strain in outbreaks of LD. The pathogenesis of LD infection initiates with the attachment of the bacterial cells to the host cells, and subsequent intracellular replication. Following invasion, Legionella spp. activates its virulence mechanisms: generation of specific compartments of Legionella-containing vacuole (LCV), and expression of genes that encode a type IV secretion system (T4SS) for the translocation of proteins. The ability of L. pneumophila to transmigrate across the lung’s epithelium barrier leads to bacteremia, spread, and invasion of many organs with subsequent manifestations, complications, and septic shock. The clinical manifestations of LD depend on the bacterial load in the aerosol, the virulence factors, and the immune status of the patient. The infection has two distinct forms: the non- pneumatic form or Pontiac fever, which is a milder febrile flu-like illness, and LD, a more severe form, which includes pneumonia. In addition, the extrapulmonary involvement of LD can include heart, brain, abdomen, and joints.
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Affiliation(s)
- Valeria Iliadi
- Izhevsk State Medical Academy, Kommunarov Street 281, 426034 Izhevsk, Russia
| | - Jeni Staykova
- Faculty of Public Health, Medical University of Sofia, Byalo More Str. 8, 1527 Sofia, Bulgaria
| | - Sergios Iliadis
- Izhevsk State Medical Academy, Kommunarov Street 281, 426034 Izhevsk, Russia
| | | | - Polina Sivykh
- State Budgetary Health City Polyclinic No 2 (GBUZ GB2) of Krasnodar, Seleznev Street 4/10, 350059 Krasnodar, Russia
| | - Gioulia Romanidou
- Nephrology Department, General Hospital “Sismanogleio”, 69100 Komotini, Greece
| | - Daniil F. Vardikov
- Russian Research Center for Radiology and Surgical Technologies of the Ministry of Health of the Russian Federation, Tkachey Str. 70-16, 192029 St. Petersburg, Russia
| | - Dimitrios Cassimos
- Pediatric Department, Democritus University of Thrace, 68100 Alexandroupolis, Greece
| | - Theocharis G. Konstantinidis
- Blood Transfusion Center, University General Hospital of Alexandroupolis Dragana Campus, 68100 Alexandroupolis, Greece
- Correspondence: ; Tel.: +30-2551-352005
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10
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Scheithauer L, Thiem S, Ünal CM, Dellmann A, Steinert M. Zinc Metalloprotease ProA from Legionella pneumophila Inhibits the Pro-Inflammatory Host Response by Degradation of Bacterial Flagellin. Biomolecules 2022; 12:biom12050624. [PMID: 35625552 PMCID: PMC9138289 DOI: 10.3390/biom12050624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 01/27/2023] Open
Abstract
The environmental bacterium Legionella pneumophila is an intracellular pathogen of various protozoan hosts and able to cause Legionnaires’ disease, a severe pneumonia in humans. By encoding a wide selection of virulence factors, the infectious agent possesses several strategies to manipulate its host cells and evade immune detection. In the present study, we demonstrate that the L. pneumophila zinc metalloprotease ProA functions as a modulator of flagellin-mediated TLR5 stimulation and subsequent activation of the pro-inflammatory NF-κB pathway. We found ProA to be capable of directly degrading immunogenic FlaA monomers but not the polymeric form of bacterial flagella. These results indicate a role of the protease in antagonizing immune stimulation, which was further substantiated in HEK-BlueTM hTLR5 Detection assays. Addition of purified proteins, bacterial suspensions of L. pneumophila mutant strains as well as supernatants of human lung tissue explant infection to this reporter cell line demonstrated that ProA specifically decreases the TLR5 response via FlaA degradation. Conclusively, the zinc metalloprotease ProA serves as a powerful regulator of exogenous flagellin and presumably creates an important advantage for L. pneumophila proliferation in mammalian hosts by promoting immune evasion.
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Affiliation(s)
- Lina Scheithauer
- Institut für Mikrobiologie, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany; (L.S.); (S.T.); (C.M.Ü.)
| | - Stefanie Thiem
- Institut für Mikrobiologie, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany; (L.S.); (S.T.); (C.M.Ü.)
| | - Can M. Ünal
- Institut für Mikrobiologie, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany; (L.S.); (S.T.); (C.M.Ü.)
| | - Ansgar Dellmann
- Institut für Pathologie, Städtisches Klinikum Braunschweig, Celler Straße 38, 38114 Braunschweig, Germany;
| | - Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany; (L.S.); (S.T.); (C.M.Ü.)
- Helmholtz Center for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
- Correspondence: ; Tel.: +49-(0)531-391-5802
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11
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Sacharok AL, Porsch EA, Yount TA, Keenan O, St. Geme JW. Kingella kingae PilC1 and PilC2 are adhesive multifunctional proteins that promote bacterial adherence, twitching motility, DNA transformation, and pilus biogenesis. PLoS Pathog 2022; 18:e1010440. [PMID: 35353876 PMCID: PMC9000118 DOI: 10.1371/journal.ppat.1010440] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 04/11/2022] [Accepted: 03/13/2022] [Indexed: 11/18/2022] Open
Abstract
The gram-negative bacterium Kingella kingae is a leading cause of osteoarticular infections in young children and initiates infection by colonizing the oropharynx. Adherence to respiratory epithelial cells represents an initial step in the process of K. kingae colonization and is mediated in part by type IV pili. In previous work, we observed that elimination of the K. kingae PilC1 and PilC2 pilus-associated proteins resulted in non-piliated organisms that were non-adherent, suggesting that PilC1 and PilC2 have a role in pilus biogenesis. To further define the functions of PilC1 and PilC2, in this study we eliminated the PilT retraction ATPase in the ΔpilC1ΔpilC2 mutant, thereby blocking pilus retraction and restoring piliation. The resulting strain was non-adherent in assays with cultured epithelial cells, supporting the possibility that PilC1 and PilC2 have adhesive activity. Consistent with this conclusion, purified PilC1 and PilC2 were capable of saturable binding to epithelial cells. Additional analysis revealed that PilC1 but not PilC2 also mediated adherence to selected extracellular matrix proteins, underscoring the differential binding specificity of these adhesins. Examination of deletion constructs and purified PilC1 and PilC2 fragments localized adhesive activity to the N-terminal region of both PilC1 and PilC2. The deletion constructs also localized the twitching motility property to the N-terminal region of these proteins. In contrast, the deletion constructs established that the pilus biogenesis function of PilC1 and PilC2 resides in the C-terminal region of these proteins. Taken together, these results provide definitive evidence that PilC1 and PilC2 are adhesins and localize adhesive activity and twitching motility to the N-terminal domain and biogenesis to the C-terminal domain. Kingella kingae is an emerging pediatric pathogen that is a leading cause of osteoarticular infections in children under the age of four. Adherence to epithelial cells is thought to be the first step in K. kingae colonization of the host and a prerequisite for invasive disease. Previous work has established that type IV pili are responsible for K. kingae adherence to host cells. In this work we identify the K. kingae pilus adhesins and localize the adhesive region to the N-terminal domain of these two proteins. We further establish that the two adhesins have distinct binding specificities and also influence other biologic processes. Our study provides new insights into the adherence mechanisms of an increasingly recognized pediatric pathogen and furthers our understanding of K. kingae interactions with host cells, identifying new potential therapeutic targets.
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Affiliation(s)
- Alexandra L. Sacharok
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Eric A. Porsch
- Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Taylor A. Yount
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Orlaith Keenan
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Joseph W. St. Geme
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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12
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A noncanonical cytochrome c stimulates calcium binding by PilY1 for type IVa pili formation. Proc Natl Acad Sci U S A 2022; 119:2115061119. [PMID: 35121662 PMCID: PMC8833165 DOI: 10.1073/pnas.2115061119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2021] [Indexed: 12/23/2022] Open
Abstract
Type IVa pili (T4aP) are versatile bacterial cell surface structures that undergo extension/adhesion/retraction cycles powered by the cell envelope-spanning T4aP machine. In this machine, a complex composed of four minor pilins and PilY1 primes T4aP extension and is also present at the pilus tip mediating adhesion. Similar to many several other bacteria, Myxococcus xanthus contains multiple minor pilins/PilY1 sets that are incompletely understood. Here, we report that minor pilins and PilY1 (PilY1.1) of cluster_1 form priming and tip complexes contingent on calcium and a noncanonical cytochrome c (TfcP) with an unusual His/Cys heme ligation. We provide evidence that TfcP is unlikely to participate in electron transport and instead stimulates calcium binding by PilY1.1 at low-calcium concentrations, thereby stabilizing PilY1.1 and enabling T4aP function in a broader range of calcium concentrations. These results not only identify a previously undescribed function of cytochromes c but also illustrate how incorporation of an accessory factor expands the environmental range under which the T4aP system functions.
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13
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Ellison CK, Whitfield GB, Brun YV. Type IV Pili: Dynamic Bacterial Nanomachines. FEMS Microbiol Rev 2021; 46:6425739. [PMID: 34788436 DOI: 10.1093/femsre/fuab053] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/08/2021] [Indexed: 01/19/2023] Open
Abstract
Bacteria and archaea rely on appendages called type IV pili (T4P) to participate in diverse behaviors including surface sensing, biofilm formation, virulence, protein secretion, and motility across surfaces. T4P are broadly distributed fibers that dynamically extend and retract, and this dynamic activity is essential for their function in broad processes. Despite the essentiality of dynamics in T4P function, little is known about the role of these dynamics and molecular mechanisms controlling them. Recent advances in microscopy have yielded insight into the role of T4P dynamics in their diverse functions and recent structural work has expanded what is known about the inner workings of the T4P motor. This review discusses recent progress in understanding the function, regulation, and mechanisms of T4P dynamics.
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Affiliation(s)
- Courtney K Ellison
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Gregory B Whitfield
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Yves V Brun
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
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14
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L Dragan A, E Voth D. Take my breath away: studying pathogen invasion of the human lung using primary tissue models. Pathog Dis 2021; 79:6177680. [PMID: 33734371 DOI: 10.1093/femspd/ftab016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/16/2021] [Indexed: 01/15/2023] Open
Abstract
The human pulmonary environment is complex, containing a matrix of cells, including fibroblasts, epithelial cells, interstitial macrophages, alveolar macrophages and neutrophils. When confronted with foreign material or invading pathogens, these cells mount a robust response. Nevertheless, many bacterial pathogens with an intracellular lifecycle stage exploit this environment for replication and survival. These include, but are not limited to, Coxiella burnetii, Legionella pneumophila, Yersinia pestis, Mycobacterium tuberculosis and Staphylococcus aureus. Currently, few human disease-relevant model systems exist for studying host-pathogen interactions during these bacterial infections in the lung. Here, we present two novel infection platforms, human alveolar macrophages (hAMs) and human precision-cut lung slices (hPCLS), along with an up-to-date synopsis of research using said models. Additionally, alternative uses for these systems in the absence of pathogen involvement are presented, such as tissue banking and further characterization of the human lung environment. Overall, hAMs and hPCLS allow novel human disease-relevant investigations that other models, such as cell lines and animal models, cannot completely provide.
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Affiliation(s)
- Amanda L Dragan
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Daniel E Voth
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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15
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Scheithauer L, Thiem S, Schmelz S, Dellmann A, Büssow K, Brouwer RMHJ, Ünal CM, Blankenfeldt W, Steinert M. Zinc metalloprotease ProA of Legionella pneumophila increases alveolar septal thickness in human lung tissue explants by collagen IV degradation. Cell Microbiol 2021; 23:e13313. [PMID: 33491325 DOI: 10.1111/cmi.13313] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 01/25/2023]
Abstract
ProA is a secreted zinc metalloprotease of Legionella pneumophila causing lung damage in animal models of Legionnaires' disease. Here we demonstrate that ProA promotes infection of human lung tissue explants (HLTEs) and dissect the contribution to cell type specific replication and extracellular virulence mechanisms. For the first time, we reveal that co-incubation of HLTEs with purified ProA causes a significant increase of the alveolar septal thickness. This destruction of connective tissue fibres was further substantiated by collagen IV degradation assays. The moderate attenuation of a proA-negative mutant in A549 epithelial cells and THP-1 macrophages suggests that effects of ProA in tissue mainly result from extracellular activity. Correspondingly, ProA contributes to dissemination and serum resistance of the pathogen, which further expands the versatile substrate spectrum of this thermolysin-like protease. The crystal structure of ProA at 1.48 Å resolution showed high congruence to pseudolysin of Pseudomonas aeruginosa, but revealed deviations in flexible loops, the substrate binding pocket S1 ' and the repertoire of cofactors, by which ProA can be distinguished from respective homologues. In sum, this work specified virulence features of ProA at different organisational levels by zooming in from histopathological effects in human lung tissue to atomic details of the protease substrate determination.
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Affiliation(s)
- Lina Scheithauer
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stefanie Thiem
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stefan Schmelz
- Structure and Function of Proteins, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Ansgar Dellmann
- Institut für Pathologie, Städtisches Klinikum Braunschweig gGmbH, Braunschweig, Germany
| | - Konrad Büssow
- Structure and Function of Proteins, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - René M H J Brouwer
- Herz-, Thorax-, Gefäßchirurgie, Städtisches Klinikum Braunschweig gGmbH, Braunschweig, Germany.,Institut für Psychologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Can M Ünal
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.,Fen Fakültesi, Turkish-German University, Istanbul, Turkey
| | - Wulf Blankenfeldt
- Structure and Function of Proteins, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany.,Institut für Biochemie, Biotechnologie und Bioinformatik, Technische Universität Braunschweig, Braunschweig, Germany
| | - Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
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16
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Graham KJ, Burrows LL. More than a feeling: microscopy approaches to understanding surface-sensing mechanisms. J Bacteriol 2020; 203:JB.00492-20. [PMID: 33077631 PMCID: PMC8095462 DOI: 10.1128/jb.00492-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The mechanisms by which bacteria sense and respond to surface attachment have long been a mystery. Our understanding of the structure and dynamics of bacterial appendages, notably type IV pili (T4P), provided new insights into the potential ways that bacteria sense surfaces. T4P are ubiquitous, retractable hair-like adhesins that until recently were difficult to image in the absence of fixation due to their nanoscale size. This review focuses on recent microscopy innovations used to visualize T4P in live cells to reveal the dynamics of their retraction and extension. We discuss recently proposed mechanisms by which T4P facilitate bacterial surface sensing, including the role of surface-exposed PilY1, two-component signal transduction pathways, force-induced structural modifications of the major pilin, and altered dynamics of the T4P motor complex.
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Affiliation(s)
- Katherine J Graham
- Department of Biochemistry and Biomedical Sciences, and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton ON Canada L8S4K1
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences, and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton ON Canada L8S4K1
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17
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Treuner-Lange A, Chang YW, Glatter T, Herfurth M, Lindow S, Chreifi G, Jensen GJ, Søgaard-Andersen L. PilY1 and minor pilins form a complex priming the type IVa pilus in Myxococcus xanthus. Nat Commun 2020; 11:5054. [PMID: 33028835 PMCID: PMC7541494 DOI: 10.1038/s41467-020-18803-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 09/14/2020] [Indexed: 01/05/2023] Open
Abstract
Type IVa pili are ubiquitous and versatile bacterial cell surface filaments that undergo cycles of extension, adhesion and retraction powered by the cell-envelope spanning type IVa pilus machine (T4aPM). The overall architecture of the T4aPM and the location of 10 conserved core proteins within this architecture have been elucidated. Here, using genetics, cell biology, proteomics and cryo-electron tomography, we demonstrate that the PilY1 protein and four minor pilins, which are widely conserved in T4aP systems, are essential for pilus extension in Myxococcus xanthus and form a complex that is an integral part of the T4aPM. Moreover, these proteins are part of the extended pilus. Our data support a model whereby the PilY1/minor pilin complex functions as a priming complex in T4aPM for pilus extension, a tip complex in the extended pilus for adhesion, and a cork for terminating retraction to maintain a priming complex for the next round of extension.
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Affiliation(s)
- Anke Treuner-Lange
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Yi-Wei Chang
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA, 91125, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 422 Curie Boulevard, Philadelphia, PA, 19104, USA
| | - Timo Glatter
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Marco Herfurth
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Steffi Lindow
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Georges Chreifi
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA, 91125, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA, 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Lotte Søgaard-Andersen
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.
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18
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Zhao X, Duan X, Dai Y, Zhen J, Guo J, Zhang K, Wang X, Kuang Z, Wang H, Niu J, Fan L, Xie J. Mycobacterium Von Willebrand factor protein MSMEG_3641 is involved in biofilm formation and intracellular survival. Future Microbiol 2020; 15:1033-1044. [PMID: 32811177 DOI: 10.2217/fmb-2020-0064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aim: Mycobacterium tuberculosis in vitro biofilm is associated with the virulence and persistence capability. Our aim is to delineate factors involved in biofilms development. Materials & methods: We performed transposon mutants screen and found that mutation of MSMEG_3641, a homolog of M. tuberculosis Rv1836c, can change M. smegmatis colony morphology and biofilm. Results: MSMEG_3641 contains a vWA domain that is highly conserved among Mycobacteria. The phenotypes of MSMEG_3641 mutants include disrupted biofilm, weakened migration ability and changed colony morphology. All phenotypes might be contributed to the enhanced cell wall permeability and declined cell aggregation ability. Conclusion: To our knowledge, this is the first report concerning the mycobacteria Von Willebrand factor domain function, especially in colony morphology and biofilm development.
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Affiliation(s)
- Xiaokang Zhao
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Xiangke Duan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Yongdong Dai
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Junfeng Zhen
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Jiaohan Guo
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Ke Zhang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Xiaoyu Wang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Zhongmei Kuang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Hao Wang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Jingjing Niu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Lin Fan
- Shanghai Clinic & Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai Key Laboratory of Tuberculosis, Shanghai 200433, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment & Bio-Resource of The Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
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19
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Palusinska-Szysz M, Luchowski R, Gruszecki WI, Choma A, Szuster-Ciesielska A, Lück C, Petzold M, Sroka-Bartnicka A, Kowalczyk B. The Role of Legionella pneumophila Serogroup 1 Lipopolysaccharide in Host-Pathogen Interaction. Front Microbiol 2019; 10:2890. [PMID: 31921066 PMCID: PMC6927915 DOI: 10.3389/fmicb.2019.02890] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 12/02/2019] [Indexed: 11/13/2022] Open
Abstract
The Legionella pneumophila TF3/1 mutant of the Corby strain, which possesses a point mutation in the active site of the O-acetyltransferase, synthesized the polysaccharide chain with a reduced degree of substitution with O-acetyl groups. The mutant did not produce a high-molecular-weight lipopolysaccharide (LPS) fraction above 12 kDa. The disturbances in LPS synthesis have an effect on the composition of other macromolecules (lipids and proteins), as indicated by differences in the infrared absorption spectra between the L. pneumophila Corby strain and its TF3/1 mutant. The wild-type strain contained less N+-CH3 and C-N groups as well as more CH3 groups than the mutant. The fatty acid composition showed that the wild type strain synthesized more branched acyl residues (a15:0, i16:0, and a17:0), a less unsaturated acid (16:1), and a straight-chain acid (18:0) than the mutant. The mutant synthesized approximately twice more a long-chain fatty acid (20:0) than the wild type. The main differences in the phospholipids between both strains were found in the classes of phosphatidylcholines and phosphatidylglycerols (PG). Substantial differences in the cell surface topography of these bacteria and their nanomechanical properties were shown by atomic force microscopy (AFM). The wild type strain had no undulated surface and produced numerous vesicles. In the case of the mutant type, the vesicles were not numerous, but there were grooves on the cell surface. The average roughness of the cell surface of the mutant was approximately twofold higher than in the wild-type strain. In turn, the wild-type strain exhibited much better adhesive properties than the mutant. The kinetic study of the interaction between the L. pneumophila strains and Acanthamoeba castellanii monitored by Förster resonance energy transfer revealed a pronounced difference, i.e., almost instantaneous and highly efficient binding of the L. pneumophila Corby strain to the amoeba surface, followed by penetration into the amoeba cells. This process was clearly not as efficient in the case of the mutant. The results point to LPS and, in particular, to the length of the polysaccharide fraction as an important L. pneumophila determinant involved in the process of adhesion to the host cell.
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Affiliation(s)
- Marta Palusinska-Szysz
- Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Rafal Luchowski
- Department of Biophysics, Faculty of Mathematics, Physics and Computer Science, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland
| | - Wieslaw I Gruszecki
- Department of Biophysics, Faculty of Mathematics, Physics and Computer Science, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland
| | - Adam Choma
- Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Agnieszka Szuster-Ciesielska
- Department of Virology and Immunology, Faculty of Biology and Biotechnology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Christian Lück
- National Reference Laboratory for Legionella, Institute of Medical Microbiology and Hygiene, University of Technology Dresden, Dresden, Germany
| | - Markus Petzold
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Anna Sroka-Bartnicka
- Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland.,Department of Biopharmacy, Medical University of Lublin, Lublin, Poland
| | - Bozena Kowalczyk
- Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
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20
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Abdel-Nour M, Su H, Duncan C, Li S, Raju D, Shamoun F, Valton M, Ginevra C, Jarraud S, Guyard C, Kerman K, Terebiznik MR. Polymorphisms of a Collagen-Like Adhesin Contributes to Legionella pneumophila Adhesion, Biofilm Formation Capacity and Clinical Prevalence. Front Microbiol 2019; 10:604. [PMID: 31024468 PMCID: PMC6460258 DOI: 10.3389/fmicb.2019.00604] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/11/2019] [Indexed: 11/22/2022] Open
Abstract
Legionellosis is a severe respiratory illness caused by the inhalation of aerosolized water droplets contaminated with the opportunistic pathogen Legionella pneumophila. The ability of L. pneumophila to produce biofilms has been associated with its capacity to colonize and persist in human-made water reservoirs and distribution systems, which are the source of legionellosis outbreaks. Nevertheless, the factors that mediate L. pneumophila biofilm formation are largely unknown. In previous studies we reported that the adhesin Legionella collagen-like protein (Lcl), is required for auto-aggregation, attachment to multiple surfaces and the formation of biofilms. Lcl structure contains three distinguishable regions: An N-terminal region with a predicted signal sequence, a central region containing tandem collagen-like repeats (R-domain) and a C-terminal region (C-domain) with no significant homology to other known proteins. Lcl R-domain encodes tandem repeats of the collagenous tripeptide Gly-Xaa-Yaa (GXY), a motif that is key for the molecular organization of mammalian collagen and mediates the binding of collagenous proteins to different cellular and environmental ligands. Interestingly, Lcl is polymorphic in the number of GXY tandem repeats. In this study, we combined diverse biochemical, genetic, and cellular approaches to determine the role of Lcl domains and GXY repeats polymorphisms on the structural and functional properties of Lcl, as well as on bacterial attachment, aggregation and biofilm formation. Our results indicate that the R-domain is key for assembling Lcl collagenous triple-helices and has a more preponderate role over the C-domain in Lcl adhesin binding properties. We show that Lcl molecules oligomerize to form large supramolecular complexes to which both, R and C-domains are required. Furthermore, we found that the number of GXY tandem repeats encoded in Lcl R-domain correlates positively with the binding capabilities of Lcl and with the attachment and biofilm production capacity of L. pneumophila strains. Accordingly, the number of GXY tandem repeats in Lcl influences the clinical prevalence of L. pneumophila strains. Therefore, the number of Lcl tandem repeats could be considered as a potential predictor for virulence in L. pneumophila isolates.
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Affiliation(s)
- Mena Abdel-Nour
- Ontario Agency for Health Protection and Promotion, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,The Mount Sinai Hospital, Toronto, ON, Canada
| | - Han Su
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Carla Duncan
- Ontario Agency for Health Protection and Promotion, Toronto, ON, Canada
| | - Shaopei Li
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Deepa Raju
- Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto at Scarborough, Toronto, ON, Canada
| | - Feras Shamoun
- Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto at Scarborough, Toronto, ON, Canada
| | - Marine Valton
- Ontario Agency for Health Protection and Promotion, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,Polytech Clermont-Ferrand, Aubière, France
| | - Christophe Ginevra
- CIRI-International Center for Infectiology Research, Legionella Pathogenesis Team, Université de Lyon, Lyon, France.,INSERM U1111, Lyon, France.,Centre International de Recherche en Infectiologie, Claude Bernard University Lyon 1, Lyon, France.,National Center for Legionella, Hospices Civils de Lyon, Lyon, France
| | - Sophie Jarraud
- CIRI-International Center for Infectiology Research, Legionella Pathogenesis Team, Université de Lyon, Lyon, France.,INSERM U1111, Lyon, France.,Centre International de Recherche en Infectiologie, Claude Bernard University Lyon 1, Lyon, France.,National Center for Legionella, Hospices Civils de Lyon, Lyon, France
| | - Cyril Guyard
- Ontario Agency for Health Protection and Promotion, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,The Mount Sinai Hospital, Toronto, ON, Canada.,BIOASTER Microbiology Technology Institute, Lyon, France
| | - Kagan Kerman
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Mauricio R Terebiznik
- Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto at Scarborough, Toronto, ON, Canada
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21
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Scheithauer L, Steinert M. Infection of Human Lung Tissue Explants (HLTEs) with Legionella pneumophila. Methods Mol Biol 2019; 1921:323-331. [PMID: 30694502 DOI: 10.1007/978-1-4939-9048-1_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Legionnaires' disease is a severe pneumonia caused by inhalation of Legionella pneumophila. Although powerful infection models ranging from monocellular host systems to mammals were developed, numerous intra- and extracellular interactions of L. pneumophila factors with human lung tissue structures remain unknown. Therefore, we developed and applied a novel infection model for Legionnaires' disease comprising living human lung tissue explants (HLTEs). This model allows analyzing Legionella infections at a unique level of complexity and narrows the gap between current infection models and postmortem histopathology analyses of infected patients. Here we describe the infection of tumor-free pulmonary tissue samples from patients undergoing lobe- or pneumectomy because of lung cancer. The method comprises bacterial cultivation, preparation of HLTEs, and infection of HLTEs. The infected tissue samples allow to characterize tissue damage, bacterial localization, dissemination and growth kinetics, and the host's molecular response.
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Affiliation(s)
- Lina Scheithauer
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Michael Steinert
- Institut für Mikrobiologie, Technische Universität Braunschweig, Braunschweig, Germany.
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22
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Peptidyl-Prolyl- cis/ trans-Isomerases Mip and PpiB of Legionella pneumophila Contribute to Surface Translocation, Growth at Suboptimal Temperature, and Infection. Infect Immun 2018; 87:IAI.00939-17. [PMID: 30323027 DOI: 10.1128/iai.00939-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 09/12/2018] [Indexed: 12/31/2022] Open
Abstract
The gammaproteobacterium Legionella pneumophila is the causative agent of Legionnaires' disease, an atypical pneumonia that manifests itself with severe lung damage. L. pneumophila, a common inhabitant of freshwater environments, replicates in free-living amoebae and persists in biofilms in natural and man-made water systems. Its environmental versatility is reflected in its ability to survive and grow within a broad temperature range as well as its capability to colonize and infect a wide range of hosts, including protozoa and humans. Peptidyl-prolyl-cis/trans-isomerases (PPIases) are multifunctional proteins that are mainly involved in protein folding and secretion in bacteria. In L. pneumophila the surface-associated PPIase Mip was shown to facilitate the establishment of the intracellular infection cycle in its early stages. The cytoplasmic PpiB was shown to promote cold tolerance. Here, we set out to analyze the interrelationship of these two relevant PPIases in the context of environmental fitness and infection. We demonstrate that the PPIases Mip and PpiB are important for surfactant-dependent sliding motility and adaptation to suboptimal temperatures, features that contribute to the environmental fitness of L. pneumophila Furthermore, they contribute to infection of the natural host Acanthamoeba castellanii as well as human macrophages and human explanted lung tissue. These effects were additive in the case of sliding motility or synergistic in the case of temperature tolerance and infection, as assessed by the behavior of the double mutant. Accordingly, we propose that Mip and PpiB are virulence modulators of L. pneumophila with compensatory action and pleiotropic effects.
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23
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Best AM, Abu Kwaik Y. Evasion of phagotrophic predation by protist hosts and innate immunity of metazoan hosts by Legionella pneumophila. Cell Microbiol 2018; 21:e12971. [PMID: 30370624 DOI: 10.1111/cmi.12971] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/08/2018] [Accepted: 10/24/2018] [Indexed: 12/18/2022]
Abstract
Legionella pneumophila is a ubiquitous environmental bacterium that has evolved to infect and proliferate within amoebae and other protists. It is thought that accidental inhalation of contaminated water particles by humans is what has enabled this pathogen to proliferate within alveolar macrophages and cause pneumonia. However, the highly evolved macrophages are equipped with more sophisticated innate defence mechanisms than are protists, such as the evolution of phagotrophic feeding into phagocytosis with more evolved innate defence processes. Not surprisingly, the majority of proteins involved in phagosome biogenesis (~80%) have origins in the phagotrophy stage of evolution. There are a plethora of highly evolved cellular and innate metazoan processes, not represented in protist biology, that are modulated by L. pneumophila, including TLR2 signalling, NF-κB, apoptotic and inflammatory processes, histone modification, caspases, and the NLRC-Naip5 inflammasomes. Importantly, L. pneumophila infects haemocytes of the invertebrate Galleria mellonella, kill G. mellonella larvae, and proliferate in and kill Drosophila adult flies and Caenorhabditis elegans. Although coevolution with protist hosts has provided a substantial blueprint for L. pneumophila to infect macrophages, we discuss the further evolutionary aspects of coevolution of L. pneumophila and its adaptation to modulate various highly evolved innate metazoan processes prior to becoming a human pathogen.
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Affiliation(s)
- Ashley M Best
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, Kentucky
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, Kentucky.,Center for Predictive Medicine, College of Medicine, University of Louisville, Louisville, Kentucky
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24
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Sun S, Noorian P, McDougald D. Dual Role of Mechanisms Involved in Resistance to Predation by Protozoa and Virulence to Humans. Front Microbiol 2018; 9:1017. [PMID: 29867902 PMCID: PMC5967200 DOI: 10.3389/fmicb.2018.01017] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/30/2018] [Indexed: 12/12/2022] Open
Abstract
Most opportunistic pathogens transit in the environment between hosts and the environment plays a significant role in the evolution of protective traits. The coincidental evolution hypothesis suggests that virulence factors arose as a response to other selective pressures rather for virulence per se. This idea is strongly supported by the elucidation of bacterial-protozoal interactions. In response to protozoan predation, bacteria have evolved various defensive mechanisms which may also function as virulence factors. In this review, we summarize the dual role of factors involved in both grazing resistance and human pathogenesis, and compare the traits using model intracellular and extracellular pathogens. Intracellular pathogens rely on active invasion, blocking of the phagosome and lysosome fusion and resistance to phagocytic digestion to successfully invade host cells. In contrast, extracellular pathogens utilize toxin secretion and biofilm formation to avoid internalization by phagocytes. The complexity and diversity of bacterial virulence factors whose evolution is driven by protozoan predation, highlights the importance of protozoa in evolution of opportunistic pathogens.
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Affiliation(s)
- Shuyang Sun
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia
| | - Parisa Noorian
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia.,School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Diane McDougald
- ithree Institute, University of Technology Sydney, Sydney, NSW, Australia.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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25
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Starr AE, Deeke SA, Li L, Zhang X, Daoud R, Ryan J, Ning Z, Cheng K, Nguyen LVH, Abou-Samra E, Lavallée-Adam M, Figeys D. Proteomic and Metaproteomic Approaches to Understand Host–Microbe Interactions. Anal Chem 2017; 90:86-109. [DOI: 10.1021/acs.analchem.7b04340] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Amanda E. Starr
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Shelley A. Deeke
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Leyuan Li
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Xu Zhang
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Rachid Daoud
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - James Ryan
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Zhibin Ning
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Kai Cheng
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Linh V. H. Nguyen
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Elias Abou-Samra
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Mathieu Lavallée-Adam
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Daniel Figeys
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
- Molecular Architecture of Life Program, Canadian Institute for Advanced Research, Toronto, Ontario, M5G 1M1, Canada
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26
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Appelt S, Heuner K. The Flagellar Regulon of Legionella-A Review. Front Cell Infect Microbiol 2017; 7:454. [PMID: 29104863 PMCID: PMC5655016 DOI: 10.3389/fcimb.2017.00454] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 10/06/2017] [Indexed: 12/15/2022] Open
Abstract
The Legionella genus comprises more than 60 species. In particular, Legionella pneumophila is known to cause severe illnesses in humans. Legionellaceae are ubiquitous inhabitants of aquatic environments. Some Legionellaceae are motile and their motility is important to move around in habitats. Motility can be considered as a potential virulence factor as already shown for various human pathogens. The genes of the flagellar system, regulator and structural genes, are structured in hierarchical levels described as the flagellar regulon. Their expression is modulated by various environmental factors. For L. pneumophila it was shown that the expression of genes of the flagellar regulon is modulated by the actual growth phase and temperature. Especially, flagellated Legionella are known to express genes during the transmissive phase of growth that are involved in the expression of virulence traits. It has been demonstrated that the alternative sigma-28 factor is part of the link between virulence expression and motility. In the following review, the structure of the flagellar regulon of L. pneumophila is discussed and compared to other flagellar systems of different Legionella species. Recently, it has been described that Legionella micdadei and Legionella fallonii contain a second putative partial flagellar system. Hence, the report will focus on flagellated and non-flagellated Legionella strains, phylogenetic relationships, the role and function of the alternative sigma factor (FliA) and its anti-sigma-28 factor (FlgM).
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Affiliation(s)
- Sandra Appelt
- Highly Pathogenic Microorganisms, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Klaus Heuner
- Cellular Interactions of Bacterial Pathogens, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
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27
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Divergent evolution of Di-lysine ER retention vs. farnesylation motif-mediated anchoring of the AnkB virulence effector to the Legionella-containing vacuolar membrane. Sci Rep 2017; 7:5123. [PMID: 28698607 PMCID: PMC5506055 DOI: 10.1038/s41598-017-05211-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/24/2017] [Indexed: 11/26/2022] Open
Abstract
Within macrophages and amoeba, the Legionella-containing vacuole (LCV) membrane is derived from the ER. The bona fide F-box AnkB effector protein of L. pneumophila strain AA100/130b is anchored to the cytosolic side of the LCV membrane through host-mediated farnesylation of its C-terminal eukaryotic “CaaX” motif. Here we show that the AnkB homologue of the Paris strain has a frame shift mutation that led to a loss of the CaaX motif and a concurrent generation of a unique C-terminal KNKYAP motif, which resembles the eukaryotic di-lysine ER-retention motif (KxKxx). Our phylogenetic analyses indicate that environmental isolates of L. pneumophila have a potential positive selection for the ER-retention KNKYAP motif. The AnkB-Paris effector is localized to the LCV membrane most likely through the ER-retention motif. Its ectopic expression in HEK293T cells localizes it to the perinuclear ER region and it trans-rescues the ankB mutant of strain AA100/130b in intra-vacuolar replication. The di-lysine ER retention motif of AnkB-Paris is indispensable for function; most likely as an ER retention motif that enables anchoring to the ER-derived LCV membrane. Our findings show divergent evolution of the ankB allele in exploiting either host farnesylation or the ER retention motif to be anchored into the LCV membrane.
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