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Busby JN, Trevelyan S, Pegg CL, Kerr ED, Schulz BL, Chassagnon I, Landsberg MJ, Weston MK, Hurst MRH, Lott JS. The ABC toxin complex from Yersinia entomophaga can package three different cytotoxic components expressed from distinct genetic loci in an unfolded state: the structures of both shell and cargo. IUCRJ 2024; 11:299-308. [PMID: 38512773 PMCID: PMC11067744 DOI: 10.1107/s2052252524001969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 02/28/2024] [Indexed: 03/23/2024]
Abstract
Bacterial ABC toxin complexes (Tcs) comprise three core proteins: TcA, TcB and TcC. The TcA protein forms a pentameric assembly that attaches to the surface of target cells and penetrates the cell membrane. The TcB and TcC proteins assemble as a heterodimeric TcB-TcC subcomplex that makes a hollow shell. This TcB-TcC subcomplex self-cleaves and encapsulates within the shell a cytotoxic `cargo' encoded by the C-terminal region of the TcC protein. Here, we describe the structure of a previously uncharacterized TcC protein from Yersinia entomophaga, encoded by a gene at a distant genomic location from the genes encoding the rest of the toxin complex, in complex with the TcB protein. When encapsulated within the TcB-TcC shell, the C-terminal toxin adopts an unfolded and disordered state, with limited areas of local order stabilized by the chaperone-like inner surface of the shell. We also determined the structure of the toxin cargo alone and show that when not encapsulated within the shell, it adopts an ADP-ribosyltransferase fold most similar to the catalytic domain of the SpvB toxin from Salmonella typhimurium. Our structural analysis points to a likely mechanism whereby the toxin acts directly on actin, modifying it in a way that prevents normal polymerization.
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Affiliation(s)
- Jason N. Busby
- School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Sarah Trevelyan
- School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Cassandra L. Pegg
- School of Chemistry and Molecular Biosciences, University of Central Queensland, Brisbane, Queensland 4072, Australia
| | - Edward D. Kerr
- School of Chemistry and Molecular Biosciences, University of Central Queensland, Brisbane, Queensland 4072, Australia
| | - Benjamin L. Schulz
- School of Chemistry and Molecular Biosciences, University of Central Queensland, Brisbane, Queensland 4072, Australia
| | - Irene Chassagnon
- School of Chemistry and Molecular Biosciences, University of Central Queensland, Brisbane, Queensland 4072, Australia
| | - Michael J. Landsberg
- School of Chemistry and Molecular Biosciences, University of Central Queensland, Brisbane, Queensland 4072, Australia
| | - Mitchell K. Weston
- Resilient Agriculture, AgResearch, Lincoln Research Centre, Christchurch 8140, New Zealand
| | - Mark R. H. Hurst
- Resilient Agriculture, AgResearch, Lincoln Research Centre, Christchurch 8140, New Zealand
| | - J. Shaun Lott
- School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
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Budziaszek J, Pilarczyk-Zurek M, Dobosz E, Kozinska A, Nowicki D, Obszanska K, Szalewska-Pałasz A, Kern-Zdanowicz I, Sitkiewicz I, Koziel J. Studies of Streptococcus anginosus Virulence in Dictyostelium discoideum and Galleria mellonella Models. Infect Immun 2023; 91:e0001623. [PMID: 37097148 DOI: 10.1128/iai.00016-23] [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: 04/26/2023] Open
Abstract
For many years, Streptococcus anginosus has been considered a commensal colonizing the oral cavity, as well as the gastrointestinal and genitourinary tracts. However, recent epidemiological and clinical data designate this bacterium as an emerging opportunistic pathogen. Despite the reported pathogenicity of S. anginosus, the molecular mechanism underpinning its virulence is poorly described. Therefore, our goal was to develop and optimize efficient and simple infection models that can be applied to examine the virulence of S. anginosus and to study host-pathogen interactions. Using 23 S. anginosus isolates collected from different infections, including severe and superficial infections, as well as an attenuated strain devoid of CppA, we demonstrate for the first time that Dictyostelium discoideum is a suitable model for initial, fast, and large-scale screening of virulence. Furthermore, we found that another nonvertebrate animal model, Galleria mellonella, can be used to study the pathogenesis of S. anginosus infection, with an emphasis on the interactions between the pathogen and host innate immunity. Examining the profile of immune defense genes, including antimicrobial peptides, opsonins, regulators of nodulation, and inhibitors of proteases, by quantitative PCR (qPCR) we identified different immune response profiles depending on the S. anginosus strain. Using these models, we show that S. anginosus is resistant to the bactericidal activity of phagocytes, a phenomenon confirmed using human neutrophils. Notably, since we found that the data from these models corresponded to the clinical severity of infection, we propose their further application to studies of the virulence of S. anginosus.
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Affiliation(s)
- Joanna Budziaszek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Magdalena Pilarczyk-Zurek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ewelina Dobosz
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Aleksandra Kozinska
- Department of Drug Biotechnology and Bioinformatics, National Medicines Institute, Warsaw, Poland
| | - Dariusz Nowicki
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
- Department of Molecular Biology, University of Gdańsk, Gdańsk, Poland
| | - Katarzyna Obszanska
- Department of Drug Biotechnology and Bioinformatics, National Medicines Institute, Warsaw, Poland
| | | | | | - Izabela Sitkiewicz
- Institute of Biology, Warsaw University of Life Sciences-SGGW, Warsaw, Poland
| | - Joanna Koziel
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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Sänger PA, Wagner S, Liebler-Tenorio EM, Fuchs TM. Dissecting the invasion of Galleria mellonella by Yersinia enterocolitica reveals metabolic adaptations and a role of a phage lysis cassette in insect killing. PLoS Pathog 2022; 18:e1010991. [PMID: 36399504 PMCID: PMC9718411 DOI: 10.1371/journal.ppat.1010991] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/02/2022] [Accepted: 11/08/2022] [Indexed: 11/19/2022] Open
Abstract
The human pathogen Yersinia enterocolitica strain W22703 is characterized by its toxicity towards invertebrates that requires the insecticidal toxin complex (Tc) proteins encoded by the pathogenicity island Tc-PAIYe. Molecular and pathophysiological details of insect larvae infection and killing by this pathogen, however, have not been dissected. Here, we applied oral infection of Galleria mellonella (Greater wax moth) larvae to study the colonisation, proliferation, tissue invasion, and killing activity of W22703. We demonstrated that this strain is strongly toxic towards the larvae, in which they proliferate by more than three orders of magnitude within six days post infection. Deletion mutants of the genes tcaA and tccC were atoxic for the insect. W22703 ΔtccC, in contrast to W22703 ΔtcaA, initially proliferated before being eliminated from the host, thus confirming TcaA as membrane-binding Tc subunit and TccC as cell toxin. Time course experiments revealed a Tc-dependent infection process starting with midgut colonisation that is followed by invasion of the hemolymph where the pathogen elicits morphological changes of hemocytes and strongly proliferates. The in vivo transcriptome of strain W22703 shows that the pathogen undergoes a drastic reprogramming of central cell functions and gains access to numerous carbohydrate and amino acid resources within the insect. Strikingly, a mutant lacking a phage-related holin/endolysin (HE) cassette, which is located within Tc-PAIYe, resembled the phenotypes of W22703 ΔtcaA, suggesting that this dual lysis cassette may be an example of a phage-related function that has been adapted for the release of a bacterial toxin.
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Affiliation(s)
| | - Stefanie Wagner
- Friedrich-Loeffler-Institut, Institut für Molekulare Pathogenese, Jena, Germany
| | | | - Thilo M. Fuchs
- Friedrich-Loeffler-Institut, Institut für Molekulare Pathogenese, Jena, Germany
- * E-mail:
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Ménard G, Rouillon A, Cattoir V, Donnio PY. Galleria mellonella as a Suitable Model of Bacterial Infection: Past, Present and Future. Front Cell Infect Microbiol 2022; 11:782733. [PMID: 35004350 PMCID: PMC8727906 DOI: 10.3389/fcimb.2021.782733] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/01/2021] [Indexed: 12/16/2022] Open
Abstract
The increasing interest for Galleria mellonella larvae as an infection model is evidenced by the number of papers reporting its use, which increases exponentially since the early 2010s. This popularity was initially linked to limitation of conventional animal models due to financial, technical and ethical aspects. In comparison, alternative models (e.g. models using Caenorhabditis elegans, Drosophila melanogaster or G. mellonella) were cheap, simple to use and not limited by ethical regulation. Since then, similar results have been established with G. mellonella model comparatively to vertebrates, and it is more and more often used as a robust model per se, not only as an alternative to the murine model. This review attempts to summarize the current knowledge supporting the development of this model, both on immunological and microbiological aspects. For that, we focus on investigation of virulence and new therapies for the most important pathogenic bacteria. We also discuss points out directions for standardization, as well as recent advances and new perspectives for monitoring host-pathogen interactions.
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Affiliation(s)
- Guillaume Ménard
- Univ Rennes, CHU Rennes, INSERM, Bacterial Regulatory RNAs and Medicine (BRM), service de Bactériologie Hygiène-Hospitalière (SB2H), UMR_S 1230, Rennes, France
| | - Astrid Rouillon
- Univ Rennes, INSERM, Bacterial Regulatory RNAs and Medicine (BRM), UMR_S 1230, Rennes, France
| | - Vincent Cattoir
- Univ Rennes, CHU Rennes, INSERM, Bacterial Regulatory RNAs and Medicine (BRM), service de Bactériologie Hygiène-Hospitalière (SB2H), UMR_S 1230, Rennes, France
| | - Pierre-Yves Donnio
- Univ Rennes, CHU Rennes, INSERM, Bacterial Regulatory RNAs and Medicine (BRM), service de Bactériologie Hygiène-Hospitalière (SB2H), UMR_S 1230, Rennes, France
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