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Mayse LA, Movileanu L. Gating of β-Barrel Protein Pores, Porins, and Channels: An Old Problem with New Facets. Int J Mol Sci 2023; 24:12095. [PMID: 37569469 PMCID: PMC10418385 DOI: 10.3390/ijms241512095] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
β barrels are ubiquitous proteins in the outer membranes of mitochondria, chloroplasts, and Gram-negative bacteria. These transmembrane proteins (TMPs) execute a wide variety of tasks. For example, they can serve as transporters, receptors, membrane-bound enzymes, as well as adhesion, structural, and signaling elements. In addition, multimeric β barrels are common structural scaffolds among many pore-forming toxins. Significant progress has been made in understanding the functional, structural, biochemical, and biophysical features of these robust and versatile proteins. One frequently encountered fundamental trait of all β barrels is their voltage-dependent gating. This process consists of reversible or permanent conformational transitions between a large-conductance, highly permeable open state and a low-conductance, solute-restrictive closed state. Several intrinsic molecular mechanisms and environmental factors modulate this universal property of β barrels. This review article outlines the typical signatures of voltage-dependent gating. Moreover, we discuss recent developments leading to a better qualitative understanding of the closure dynamics of these TMPs.
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Affiliation(s)
- Lauren A. Mayse
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244, USA;
- Department of Biomedical and Chemical Engineering, Syracuse University, 223 Link Hall, Syracuse, NY 13244, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244, USA;
- Department of Biomedical and Chemical Engineering, Syracuse University, 223 Link Hall, Syracuse, NY 13244, USA
- The BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
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2
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Mishra S, Roy A, Dutta S. Cryo-EM-based structural insights into supramolecular assemblies of γ-hemolysin from S. aureus reveal the pore formation mechanism. Structure 2023:S0969-2126(23)00085-0. [PMID: 37019111 DOI: 10.1016/j.str.2023.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 01/31/2023] [Accepted: 03/10/2023] [Indexed: 04/07/2023]
Abstract
γ-Hemolysin (γ-HL) is a hemolytic and leukotoxic bicomponent β-pore-forming toxin (β-PFT), a potent virulence factor from the Staphylococcus aureus Newman strain. In this study, we performed single-particle cryoelectron microscopy (cryo-EM) of γ-HL in a lipid environment. We observed clustering and square lattice packing of octameric HlgAB pores on the membrane bilayer and an octahedral superassembly of octameric pore complexes that we resolved at resolution of 3.5 Å. Our atomic model further demonstrated the key residues involved in hydrophobic zipping between the rim domains of adjacent octameric complexes, providing additional structural stability in PFTs post oligomerization. We also observed extra densities at the octahedral and octameric interfaces, providing insights into the plausible lipid-binding residues involved for HlgA and HlgB components. Furthermore, the hitherto elusive N-terminal region of HlgA was also resolved in our cryo-EM map, and an overall mechanism of pore formation for bicomponent β-PFTs is proposed.
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Affiliation(s)
- Suman Mishra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Anupam Roy
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Somnath Dutta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
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3
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Harada S, Kawada H, Maehana S, Matsui H, Kubo M, Kojima F, Kitasato H, Katagiri M. Panton-Valentine Leukocidin Induces Cytokine Release and Cytotoxicity Mediated by the C5a Receptor on Rabbit Alveolar Macrophages. Jpn J Infect Dis 2021; 74:352-358. [PMID: 33518621 DOI: 10.7883/yoken.jjid.2020.657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Necrotizing pneumonia caused by Panton-Valentine leukocidin (PVL)-positive community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has high mortality rates and is currently a serious clinical issue. PVL is a two-component toxin (LukS-PV and LukF-PV). It can cause necrosis in target cells by forming pores consisting of an octamer comprised of LukS-PV and LukF-PV. However, considering the specificity of PVL towards several target cells and species, the specific effect of PVL remains controversial. Therefore, we focused on necrotizing pneumonia caused by PVL-positive S. aureus and clarified the effect of PVL on alveolar macrophages, which play a central role in innate immunity in the alveolar space. We constructed recombinant PVL (rPVL) components and stimulated alveolar macrophages isolated from rabbits to evaluate cytotoxicity and pro-inflammatory cytokine release. Recombinant LukS-PV (rLukS-PV), but not recombinant LukF-PV (rLukF-PV), induced pro-inflammatory cytokine release. Specifically, tumor necrosis factor (TNF)-α release was mediated by the C5a receptor (C5aR) expressed on rabbit alveolar macrophages, and the toxicity of rPVL, consisting of rLukS-PV and rLukF-PV, towards rabbit alveolar macrophages was mediated by the same receptor. Overall, our findings shed light on the C5aR-mediated cytotoxic effect of PVL on alveolar macrophages, which may be useful for understanding the mechanism of necrotizing pneumonia caused by PVL.
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Affiliation(s)
- Shinya Harada
- Kitasato University Graduate School of Medical Sciences, Japan.,Department of Respiratory Medicine, Kitasato University Hospital, Japan
| | - Hayato Kawada
- Department of Parasitology and Tropical Medicine, Kitasato University School of Medicine, Japan
| | - Shotaro Maehana
- Department of Microbiology, Kitasato University School of Allied Health Sciences, Japan
| | - Hidehito Matsui
- Ōmura Satoshi Memorial Institute, Kitasato University, Japan
| | - Makoto Kubo
- Division of Immunology II, Kitasato University School of Allied Health Sciences, Japan
| | - Fumiaki Kojima
- Department of Pharmacology, Kitasato University School of Allied Health Sciences, Japan
| | - Hidero Kitasato
- Department of Microbiology, Kitasato University School of Allied Health Sciences, Japan
| | - Masato Katagiri
- Kitasato University Graduate School of Medical Sciences, Japan.,Department of Respiratory Medicine, Kitasato University Hospital, Japan.,Department of Clinical Physiology, Kitasato University School of Allied Health Sciences, Japan
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4
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Toxic Shock Syndrome Toxin 1 Induces Immune Response via the Activation of NLRP3 Inflammasome. Toxins (Basel) 2021; 13:toxins13010068. [PMID: 33477467 PMCID: PMC7829800 DOI: 10.3390/toxins13010068] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 12/31/2020] [Accepted: 01/12/2021] [Indexed: 01/13/2023] Open
Abstract
Staphylococcus aureus is a Gram-positive opportunistic pathogen which causes infections in a variety of vertebrates. Virulence factors are the main pathogenesis of S. aureus as a pathogen, which induce the host’s innate and adaptive immune responses. Toxic shock syndrome toxin 1 (TSST-1) is one of the most important virulence factors of S. aureus. However, the role of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) in TSST-1-induced innate immune response is still unclear. Here, purified recombinant TSST-1 (rTSST-1) was prepared and used to stimulate mouse peritoneal macrophages. The results showed that under the action of adenosine-triphosphate (ATP), rTSST-1 significantly induced interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) production in mouse macrophages and the production was dose-dependent. In addition, rTSST-1+ATP-stimulated cytokine production in macrophage depends on the activation of toll like receptor 4 (TLR4), but not TLR2 on the cells. Furthermore, the macrophages of NLRP3−/− mice stimulated with rTSST-1+ATP showed significantly low levels of IL-1β production compared to that of wild-type mice. These results demonstrated that TSST-1 can induce the expression of inflammatory cytokines in macrophages via the activation of the TLR4 and NLRP3 signaling pathways. Our study provides new information about the mechanism of the TSST-1-inducing host’s innate immune responses.
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5
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Design and Assembly of Transmembrane Helix Barrel. J Membr Biol 2020; 253:491-497. [PMID: 33200236 DOI: 10.1007/s00232-020-00145-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/08/2020] [Indexed: 10/23/2022]
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6
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Hayakawa T, Miyazaki M, Harada S, Asakura M, Ide T. Channel-pore cation selectivity is a major determinant of Bacillus thuringiensis Cry46Ab mosquitocidal activity. Appl Microbiol Biotechnol 2020; 104:8789-8799. [DOI: 10.1007/s00253-020-10893-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/31/2020] [Accepted: 09/05/2020] [Indexed: 10/23/2022]
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7
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Tromp AT, van Strijp JAG. Studying Staphylococcal Leukocidins: A Challenging Endeavor. Front Microbiol 2020; 11:611. [PMID: 32351474 PMCID: PMC7174503 DOI: 10.3389/fmicb.2020.00611] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 03/19/2020] [Indexed: 01/01/2023] Open
Abstract
Staphylococcus aureus is a well-known colonizer of the human skin and nose, but also a human pathogen that causes a wide spectrum of diseases. It is well established that S. aureus secretes an arsenal of virulence factors that have evolved to circumvent the human immune system. A major group of S. aureus virulence factors is the bi-component β-barrel pore-forming toxins, also known as leukocidins. These pore-forming toxins target specific cells of the innate and adaptive immune system by interacting with specific receptors expressed on the cell membrane. Even though still heavily debated, clinical and epidemiological studies suggest the involvement of one of the bi-component toxin, Panton-Valentine Leukocidin (PVL), as an important factor contributing to the epidemic spread and increased virulence of CA-MRSA strains. However, the host- and cell-specificity of PVL and other leukocidins, and the lack of adequate in vivo models, fuels the controversy and impairs the appropriate assessment of their role in S. aureus pathophysiology. Currently, the mechanisms of pore-formation and the contribution of PVL and other leukocidins to S. aureus pathophysiology are incompletely understood. This review summarizes our current understanding of leukocidin pore-formation, knowledge gaps, and highlights recent findings identifying novel host-factors involved in the toxin-host interface. As a result, this review furthers emphasizes the complexity behind S. aureus leukocidin cytotoxicity and the challenges associated in the quest to study and understand these major virulence factors.
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Affiliation(s)
- Angelino T Tromp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
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8
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The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections. Toxins (Basel) 2019; 11:toxins11060332. [PMID: 31212697 PMCID: PMC6628391 DOI: 10.3390/toxins11060332] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 12/31/2022] Open
Abstract
Necrotizing soft tissue infections (NSTIs) are critical clinical conditions characterized by extensive necrosis of any layer of the soft tissue and systemic toxicity. Group A streptococci (GAS) and Staphylococcus aureus are two major pathogens associated with monomicrobial NSTIs. In the tissue environment, both Gram-positive bacteria secrete a variety of molecules, including pore-forming exotoxins, superantigens, and proteases with cytolytic and immunomodulatory functions. The present review summarizes the current knowledge about streptococcal and staphylococcal toxins in NSTIs with a special focus on their contribution to disease progression, tissue pathology, and immune evasion strategies.
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9
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Haapasalo K, Wollman AJM, de Haas CJC, van Kessel KPM, van Strijp JAG, Leake MC. Staphylococcus aureus toxin LukSF dissociates from its membrane receptor target to enable renewed ligand sequestration. FASEB J 2019; 33:3807-3824. [PMID: 30509126 PMCID: PMC6404581 DOI: 10.1096/fj.201801910r] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 10/29/2018] [Indexed: 11/11/2022]
Abstract
Staphylococcus aureus Panton-Valentine leukocidin is a pore-forming toxin targeting the human C5a receptor (hC5aR), enabling this pathogen to battle the immune response by destroying phagocytes through targeted lysis. The mechanisms that contribute to rapid cell lysis are largely unexplored. Here, we show that cell lysis may be enabled by a process of toxins targeting receptor clusters and present indirect evidence for receptor "recycling" that allows multiple toxin pores to be formed close together. With the use of live cell single-molecule super-resolution imaging, Förster resonance energy transfer and nanoscale total internal reflection fluorescence colocalization microscopy, we visualized toxin pore formation in the presence of its natural docking ligand. We demonstrate disassociation of hC5aR from toxin complexes and simultaneous binding of new ligands. This effect may free mobile receptors to amplify hyperinflammatory reactions in early stages of microbial infections and have implications for several other similar bicomponent toxins and the design of new antibiotics.-Haapasalo, K., Wollman, A. J. M., de Haas, C. J. C., van Kessel, K. P. M., van Strijp, J. A. G., Leake, M. C. Staphylococcus aureus toxin LukSF dissociates from its membrane receptor target to enable renewed ligand sequestration.
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Affiliation(s)
- Karita Haapasalo
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - Adam J. M. Wollman
- Department of Biology, Biological Physical Sciences Institute, University of York, York, United Kingdom
| | - Carla J. C. de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Kok P. M. van Kessel
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Jos A. G. van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Mark C. Leake
- Department of Biology, Biological Physical Sciences Institute, University of York, York, United Kingdom
- Department of Physics, Biological Physical Sciences Institute, University of York, York, United Kingdom
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10
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Krishnan R S, Satheesan R, Puthumadathil N, Kumar KS, Jayasree P, Mahendran KR. Autonomously Assembled Synthetic Transmembrane Peptide Pore. J Am Chem Soc 2019; 141:2949-2959. [DOI: 10.1021/jacs.8b09973] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Smrithi Krishnan R
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - Remya Satheesan
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - Neethu Puthumadathil
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - K. Santhosh Kumar
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - Poornendhu Jayasree
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - Kozhinjampara R. Mahendran
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
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11
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Mehdizadeh Gohari I, Brefo-Mensah EK, Palmer M, Boerlin P, Prescott JF. Sialic acid facilitates binding and cytotoxic activity of the pore-forming Clostridium perfringens NetF toxin to host cells. PLoS One 2018; 13:e0206815. [PMID: 30403719 PMCID: PMC6221314 DOI: 10.1371/journal.pone.0206815] [Citation(s) in RCA: 6] [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: 07/06/2018] [Accepted: 10/20/2018] [Indexed: 11/19/2022] Open
Abstract
NetF-producing type A Clostridium perfringens is an important cause of canine and foal necrotizing enteritis. NetF, related to the β-sheet pore-forming Leukocidin/Hemolysin superfamily, is considered a major virulence factor for this disease. The main purpose of this work is to demonstrate the pore-forming activity of NetF and characterize the chemical nature of its binding site. Electron microscopy using recombinant NetF (rNetF) confirmed that NetF is able to oligomerize and form large pores in equine ovarian (EO) cell membranes and sheep red blood cells. These oligomeric pores appear to be about 4–6 nm in diameter, and the number of oligomer subunits to vary from 6 to 9. Sodium periodate treatment rendered EO cells non-susceptible to NetF, suggesting that NetF binding requires cell surface carbohydrates. NetF cytotoxicity was also inhibited by a lectin that binds sialic acid, by sialidase, and by free sialic acid in excess, all of which clearly implicate sialic acid-containing membrane carbohydrates in NetF binding and/or toxicity for EO cells. Binding of NetF to sheep red blood cells was not inhibited by the gangliosides GM1, GM2 and GM3, nor did the latter promote membrane permeabilization in liposomes, suggesting that they do not constitute the cellular receptors. In contrast, treatment of EO cells with different proteases reduced their susceptibility to NetF, suggesting that the NetF receptor is a sialic acid-containing glycoprotein.
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Affiliation(s)
| | | | - Michael Palmer
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada
| | - Patrick Boerlin
- Department of Pathobiology, University of Guelph, Guelph, Ontario, Canada
| | - John F. Prescott
- Department of Pathobiology, University of Guelph, Guelph, Ontario, Canada
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12
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Staphylococcus aureus Toxins and Their Molecular Activity in Infectious Diseases. Toxins (Basel) 2018; 10:toxins10060252. [PMID: 29921792 PMCID: PMC6024779 DOI: 10.3390/toxins10060252] [Citation(s) in RCA: 234] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 12/04/2022] Open
Abstract
Staphylococcus aureus is a microorganism resident in the skin and nasal membranes with a dreadful pathogenic potential to cause a variety of community and hospital-acquired infections. The frequency of these infections is increasing and their treatment is becoming more difficult. The ability of S. aureus to form biofilms and the emergence of multidrug-resistant strains are the main reasons determining the challenge in dealing with these infections. S. aureus' infectious capacity and its success as a pathogen is related to the expression of virulence factors, among which the production of a wide variety of toxins is highlighted. For this reason, a better understanding of S. aureus toxins is needed to enable the development of new strategies to reduce their production and consequently improve therapeutic approaches. This review focuses on understanding the toxin-based pathogenesis of S. aureus and their role on infectious diseases.
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13
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Seilie ES, Bubeck Wardenburg J. Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexity. Semin Cell Dev Biol 2017; 72:101-116. [PMID: 28445785 DOI: 10.1016/j.semcdb.2017.04.003] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 03/22/2017] [Accepted: 04/18/2017] [Indexed: 12/20/2022]
Abstract
Staphylococcus aureus is a prominent human pathogen capable of infecting a variety of host species and tissue sites. This versatility stems from the pathogen's ability to secrete diverse host-damaging virulence factors. Among these factors, the S. aureus pore-forming toxins (PFTs) α-toxin and the bicomponent leukocidins, have garnered much attention for their ability to lyse cells at low concentrations and modulate disease severity. Although many of these toxins were discovered nearly a century ago, their host cell specificities have only been elucidated over the past five to six years, starting with the discovery of the eukaryotic receptor for α-toxin and rapidly followed by identification of the leukocidin receptors. The identification of these receptors has revealed the species- and cell type-specificity of toxin binding, and provided insight into non-lytic effects of PFT intoxication that contribute to disease pathogenesis.
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Affiliation(s)
- E Sachiko Seilie
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, United States; Department of Microbiology, The University of Chicago, Chicago, IL 60637, United States
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14
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Assis LM, Nedeljković M, Dessen A. New strategies for targeting and treatment of multi-drug resistant Staphylococcus aureus. Drug Resist Updat 2017; 31:1-14. [PMID: 28867240 DOI: 10.1016/j.drup.2017.03.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 02/07/2017] [Accepted: 03/23/2017] [Indexed: 12/17/2022]
Abstract
Staphylococcus aureus is a major cause of bacterial infection in humans, and has been notoriously able to acquire resistance to a variety of antibiotics. An example is methicillin-resistant S. aureus (MRSA), which despite having been initially associated with clinical settings, now is one of the key causative agents of community-acquired infections. Antibiotic resistance in S. aureus involves mechanisms ranging from drug efflux to increased expression or mutation of target proteins, and this has required innovative approaches to develop novel treatment methodologies. This review provides an overview of the major mechanisms of antibiotic resistance developed by S. aureus, and describes the emerging alternatives being sought to circumvent infection and proliferation, including new generations of classic antibiotics, synergistic approaches, antibodies, and targeting of virulence factors.
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Affiliation(s)
- L Mayrink Assis
- Brazilian National Laboratory for Biosciences (LNBio), CNPEM, Campinas, São Paulo, Brazil
| | - M Nedeljković
- Institut de Biologie Structurale (IBS), Univ Grenoble Alpes, CEA, CNRS, Bacterial Pathogenesis Group, 38044 Grenoble, France
| | - A Dessen
- Brazilian National Laboratory for Biosciences (LNBio), CNPEM, Campinas, São Paulo, Brazil; Institut de Biologie Structurale (IBS), Univ Grenoble Alpes, CEA, CNRS, Bacterial Pathogenesis Group, 38044 Grenoble, France.
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15
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Bierdeman MA, Torres AM, Caballero AR, Tang A, O'Callaghan RJ. Reactions with Antisera and Pathological Effects of Staphylococcus aureus Gamma-Toxin in the Cornea. Curr Eye Res 2017; 42:1100-1107. [PMID: 28346009 DOI: 10.1080/02713683.2017.1279636] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE This study analyzed the toxicity of purified gamma-toxin from Staphylococcus aureus and the protectiveness of antisera to gamma-toxin in the rabbit cornea. MATERIALS AND METHODS Gamma-toxin was purified from cultures of alpha-toxin deficient S. aureus strain Newman Δhla. Antisera to native gamma-toxin (Hlg) were produced in rabbits. These antisera and a commercial polyclonal antibody to recombinant HlgB (rHlgB) were analyzed for specificity and toxin neutralization. Heat-inactivated gamma-toxin, active gamma-toxin either alone or with antisera or with commercial antibody to rHlgB, was injected into the rabbit cornea to observe the pathological effects using slit lamp examination scoring (SLE) and histological analyses. RESULTS Eyes with intrastromal injection of gamma-toxin developed SLE scores that were significantly higher than eyes injected with heat-inactivated gamma-toxin (p ≤ 0.003). Slit lamp and histological examination of eyes revealed that gamma-toxin injected into the cornea mediated conjunctival injection and chemosis, iritis, fibrin accumulation in the anterior chamber, and polymorphonuclear neutrophil infiltration of the cornea and iris. Also, eyes injected with gamma-toxin plus antisera to native whole gamma-toxin or HlgB, but not with commercial antibody to rHlgB, yielded significantly lower SLE scores than eyes injected with gamma-toxin alone (p ≤ 0.003). CONCLUSIONS This study illustrates that S. aureus gamma-toxin is capable of causing significant corneal pathology. Furthermore, the use of polyclonal antisera specific for native gamma-toxin was found to inhibit the damaging effects of the toxin in the rabbit cornea.
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Affiliation(s)
- Michael A Bierdeman
- a Department of Microbiology and Immunology , University of Mississippi Medical Center , Jackson , MS , USA
| | - Angela M Torres
- a Department of Microbiology and Immunology , University of Mississippi Medical Center , Jackson , MS , USA
| | - Armando R Caballero
- a Department of Microbiology and Immunology , University of Mississippi Medical Center , Jackson , MS , USA
| | - Aihua Tang
- a Department of Microbiology and Immunology , University of Mississippi Medical Center , Jackson , MS , USA
| | - Richard J O'Callaghan
- a Department of Microbiology and Immunology , University of Mississippi Medical Center , Jackson , MS , USA
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16
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Mahendran KR, Niitsu A, Kong L, Thomson AR, Sessions RB, Woolfson DN, Bayley H. A monodisperse transmembrane α-helical peptide barrel. Nat Chem 2016; 9:411-419. [PMID: 28430192 DOI: 10.1038/nchem.2647] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 09/13/2016] [Indexed: 12/13/2022]
Abstract
The fabrication of monodisperse transmembrane barrels formed from short synthetic peptides has not been demonstrated previously. This is in part because of the complexity of the interactions between peptides and lipids within the hydrophobic environment of a membrane. Here we report the formation of a transmembrane pore through the self-assembly of 35 amino acid α-helical peptides. The design of the peptides is based on the C-terminal D4 domain of the Escherichia coli polysaccharide transporter Wza. By using single-channel current recording, we define discrete assembly intermediates and show that the pore is most probably a helix barrel that contains eight D4 peptides arranged in parallel. We also show that the peptide pore is functional and capable of conducting ions and binding blockers. Such α-helix barrels engineered from peptides could find applications in nanopore technologies such as single-molecule sensing and nucleic-acid sequencing.
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Affiliation(s)
- Kozhinjampara R Mahendran
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA UK
| | - Ai Niitsu
- School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, UK
| | - Lingbing Kong
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA UK
| | - Andrew R Thomson
- School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, UK
| | - Richard B Sessions
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.,BrisSynBio, Life Sciences Building, Tyndall Avenue, University of Bristol, Bristol BS8 1TQ, UK
| | - Derek N Woolfson
- School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, UK.,School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.,BrisSynBio, Life Sciences Building, Tyndall Avenue, University of Bristol, Bristol BS8 1TQ, UK
| | - Hagan Bayley
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA UK
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17
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Badarau A, Rouha H, Malafa S, Battles MB, Walker L, Nielson N, Dolezilkova I, Teubenbacher A, Banerjee S, Maierhofer B, Weber S, Stulik L, Logan DT, Welin M, Mirkina I, Pleban C, Zauner G, Gross K, Jägerhofer M, Magyarics Z, Nagy E. Context matters: The importance of dimerization-induced conformation of the LukGH leukocidin of Staphylococcus aureus for the generation of neutralizing antibodies. MAbs 2016; 8:1347-1360. [PMID: 27467113 PMCID: PMC5058624 DOI: 10.1080/19420862.2016.1215791] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
LukGH (LukAB) is a potent leukocidin of Staphylococcus aureus that lyses human phagocytic cells and is thought to contribute to immune evasion. Unlike the other bi-component leukocidins of S. aureus, LukGH forms a heterodimer before binding to its receptor, CD11b expressed on professional phagocytic cells, and displays significant sequence variation. We employed a high diversity human IgG1 library presented on yeast cells to discover monoclonal antibodies (mAbs) neutralizing the cytolytic activity of LukGH. Recombinant LukG and LukH monomers or a LukGH dimer were used as capture antigens in the library selections. We found that mAbs identified with LukG or LukH as bait had no or very low toxin neutralization potency. In contrast, LukGH dimer-selected antibodies proved to be highly potent, and several mAbs were able to neutralize even the most divergent LukGH variants. Based on biolayer interferometry and mesoscale discovery, the high affinity antibody binding site on the LukGH complex was absent on the individual monomers, suggesting that it was generated upon formation of the LukG-LukH dimer. X-ray crystallography analysis of the complex between the LukGH dimer and the antigen-binding fragment of a very potent mAb (PDB code 5K59) indicated that the epitope is located in the predicted cell binding region (rim domain) of LukGH. The corresponding IgG inhibited the binding of LukGH dimer to target cells. Our data suggest that knowledge of the native conformation of target molecules is essential to generate high affinity and functional mAbs.
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Affiliation(s)
- Adriana Badarau
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | - Harald Rouha
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | - Stefan Malafa
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | | | | | | | | | | | - Srijib Banerjee
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | | | - Susanne Weber
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | - Lukas Stulik
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | - Derek T Logan
- c SARomics Biostructures AB , Medicon Village, Lund , Sweden
| | - Martin Welin
- c SARomics Biostructures AB , Medicon Village, Lund , Sweden
| | - Irina Mirkina
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | - Clara Pleban
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | - Gerhild Zauner
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | - Karin Gross
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | | | - Zoltán Magyarics
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
| | - Eszter Nagy
- a Arsanis Biosciences , Campus Vienna Biocenter, Vienna , Austria
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18
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Bezrukov SM, Nestorovich EM. Inhibiting bacterial toxins by channel blockage. Pathog Dis 2016; 74:ftv113. [PMID: 26656888 PMCID: PMC4830228 DOI: 10.1093/femspd/ftv113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/15/2015] [Accepted: 11/24/2015] [Indexed: 01/01/2023] Open
Abstract
Emergent rational drug design techniques explore individual properties of target biomolecules, small and macromolecule drug candidates, and the physical forces governing their interactions. In this minireview, we focus on the single-molecule biophysical studies of channel-forming bacterial toxins that suggest new approaches for their inhibition. We discuss several examples of blockage of bacterial pore-forming and AB-type toxins by the tailor-made compounds. In the concluding remarks, the most effective rationally designed pore-blocking antitoxins are compared with the small-molecule inhibitors of ion-selective channels of neurophysiology.
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Affiliation(s)
- Sergey M Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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19
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Parker D, Ahn D, Cohen T, Prince A. Innate Immune Signaling Activated by MDR Bacteria in the Airway. Physiol Rev 2016; 96:19-53. [PMID: 26582515 DOI: 10.1152/physrev.00009.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Health care-associated bacterial pneumonias due to multiple-drug resistant (MDR) pathogens are an important public health problem and are major causes of morbidity and mortality worldwide. In addition to antimicrobial resistance, these organisms have adapted to the milieu of the human airway and have acquired resistance to the innate immune clearance mechanisms that normally prevent pneumonia. Given the limited efficacy of antibiotics, bacterial clearance from the airway requires an effective immune response. Understanding how specific airway pathogens initiate and regulate innate immune signaling, and whether this response is excessive, leading to host-induced pathology may guide future immunomodulatory therapy. We will focus on three of the most important causes of health care-associated pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, and review the mechanisms through which an inappropriate or damaging innate immune response is stimulated, as well as describe how airway pathogens cause persistent infection by evading immune activation.
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Affiliation(s)
- Dane Parker
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Danielle Ahn
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Taylor Cohen
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
| | - Alice Prince
- Departments of Pediatrics and Pharmacology, Columbia University, New York, New York
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20
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Reyes-Robles T, Torres VJ. Staphylococcus aureus Pore-Forming Toxins. Curr Top Microbiol Immunol 2016; 409:121-144. [PMID: 27406190 DOI: 10.1007/82_2016_16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Staphylococcus aureus (S. aureus) is a formidable foe equipped with an armamentarium of virulence factors to thwart host defenses and establish a successful infection. Among these virulence factors, S. aureus produces several potent secreted proteins that act as cytotoxins, predominant among them the beta-barrel pore-forming toxins. These toxins play several roles in pathogenesis, including disruption of cellular adherens junctions at epithelial barriers, alteration of intracellular signaling events, modulation of host immune responses, and killing of eukaryotic immune and non-immune cells. This chapter provides an updated overview on the S. aureus beta-barrel pore-forming cytotoxins, the identification of toxin receptors on host cells, and their roles in pathogenesis.
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Affiliation(s)
- Tamara Reyes-Robles
- Department of Microbiology, Microbial Pathogenesis Program, New York University School of Medicine, 522 First Avenue, Smilow Research Building, Room 1010, New York, NY, 10016, USA
| | - Victor J Torres
- Department of Microbiology, Microbial Pathogenesis Program, New York University School of Medicine, 522 First Avenue, Smilow Research Building, Room 1010, New York, NY, 10016, USA.
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21
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Thammavongsa V, Kim HK, Missiakas D, Schneewind O. Staphylococcal manipulation of host immune responses. Nat Rev Microbiol 2015; 13:529-43. [PMID: 26272408 DOI: 10.1038/nrmicro3521] [Citation(s) in RCA: 381] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Staphylococcus aureus, a bacterial commensal of the human nares and skin, is a frequent cause of soft tissue and bloodstream infections. A hallmark of staphylococcal infections is their frequent recurrence, even when treated with antibiotics and surgical intervention, which demonstrates the bacterium's ability to manipulate innate and adaptive immune responses. In this Review, we highlight how S. aureus virulence factors inhibit complement activation, block and destroy phagocytic cells and modify host B cell and T cell responses, and we discuss how these insights might be useful for the development of novel therapies against infections with antibiotic resistant strains such as methicillin-resistant S. aureus.
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Affiliation(s)
- Vilasack Thammavongsa
- 1] Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA. [2] Regeneron Pharmaceuticals, 755 Old Saw Mill River Road, Tarrytown, New York 10591, USA
| | - Hwan Keun Kim
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
| | - Dominique Missiakas
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
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22
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Adhikari RP, Kort T, Shulenin S, Kanipakala T, Ganjbaksh N, Roghmann MC, Holtsberg FW, Aman MJ. Antibodies to S. aureus LukS-PV Attenuated Subunit Vaccine Neutralize a Broad Spectrum of Canonical and Non-Canonical Bicomponent Leukotoxin Pairs. PLoS One 2015; 10:e0137874. [PMID: 26367030 PMCID: PMC4569305 DOI: 10.1371/journal.pone.0137874] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/22/2015] [Indexed: 11/18/2022] Open
Abstract
S. aureus vaccine development has proven particularly difficult. The conventional approach to achieve sterile immunity through opsonophagocytic killing has been largely unsuccessful. S. aureus is highly toxigenic and a great body of evidence suggests that a successful future vaccine for this organism should target extracellular toxins which are responsible for host tissue destruction and immunosuppression. Major staphylococcal toxins are alpha toxin (a single subunit hemolysin) along with a group of bicomponent pore-forming toxins (BCPFT), namely Panton-Valentine leukocidin (PVL), gamma hemolysins (HlgCB and AB), LukAB and LukED. In our previous report, an attenuated mutant of LukS-PV (PVL- S subunit) named as “LukS-mut9” elicited high immunogenic response as well as provided a significant protection in a mouse sepsis model. Recent discovery of PVL receptors shows that mice lack receptors for this toxin, thus the reported protection of mice with the PVL vaccine may relate to cross protective responses against other homologous toxins. This manuscript addresses this issue by demonstrating that polyclonal antibody generated by LukS-mut9 can neutralize other canonical and non-canonical leukotoxin pairs. In this report, we also demonstrated that several potent toxins can be created by non-canonical pairing of subunits. Out of 5 pairs of canonical and 8 pairs of non-canonical toxins tested, anti-LukS-mut9 polyclonal antibodies neutralized all except for LukAB. We also studied the potential hemolytic activities of canonical and noncanonical pairs among biocomponent toxins and discovered that a novel non-canonical pair consisting of HlgA and LukD is a highly toxic combination. This pair can lyse RBC from different species including human blood far better than alpha hemolysin. Moreover, to follow-up our last report, we explored the correlation between the levels of pre-existing antibodies to new sets of leukotoxins subunits and clinical outcomes in adult patients with S. aureus bacteremia. We found that there is an inversed correlation between the antibody titer to sepsis for leukotoxins LukS-mut9, LukF-PV, HlgC, LukE and LukAB, suggesting the risk of sepsis was significantly lower in the patients with higher antibody titer against those toxins.
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Affiliation(s)
- Rajan P. Adhikari
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
- * E-mail:
| | - Thomas Kort
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Sergey Shulenin
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | | | - Nader Ganjbaksh
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Mary-Claire Roghmann
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- VA Maryland Health Care System, Baltimore, Maryland, United States of America
| | | | - M. Javad Aman
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
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23
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Yoong P, Torres VJ. Counter inhibition between leukotoxins attenuates Staphylococcus aureus virulence. Nat Commun 2015; 6:8125. [PMID: 26330208 PMCID: PMC4562310 DOI: 10.1038/ncomms9125] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 07/21/2015] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus subverts host defences by producing a collection of virulence factors including bi-component pore-forming leukotoxins. Despite extensive sequence conservation, each leukotoxin has unique properties, including disparate cellular receptors and species specificities. How these toxins collectively influence S. aureus pathogenesis is unknown. Here we demonstrate that the leukotoxins LukSF-PV and LukED antagonize each other's cytolytic activities on leukocytes and erythrocytes by forming inactive hybrid complexes. Remarkably, LukSF-PV inhibition of LukED haemolytic activity on both human and murine erythrocytes prevents the release of nutrients required for in vitro bacterial growth. Using in vivo murine models of infection, we show that LukSF-PV negatively influences S. aureus virulence and colonization by inhibiting LukED. Thus, while S. aureus leukotoxins can certainly injure immune cells, the discovery of leukotoxin antagonism suggests that they may also play a role in reducing S. aureus virulence and maintaining infection without killing the host. Staphylococcus aureus strains produce a family of highly related toxins that puncture the cytoplasmic membrane of susceptible cells. Here, Yoong and Torres show that the toxins can counteract each other in a cell type-dependent manner by forming inactive hybrid complexes, thus modulating S. aureus virulence.
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Affiliation(s)
- Pauline Yoong
- Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA
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24
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The bicomponent pore-forming leucocidins of Staphylococcus aureus. Microbiol Mol Biol Rev 2015; 78:199-230. [PMID: 24847020 DOI: 10.1128/mmbr.00055-13] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The ability to produce water-soluble proteins with the capacity to oligomerize and form pores within cellular lipid bilayers is a trait conserved among nearly all forms of life, including humans, single-celled eukaryotes, and numerous bacterial species. In bacteria, some of the most notable pore-forming molecules are protein toxins that interact with mammalian cell membranes to promote lysis, deliver effectors, and modulate cellular homeostasis. Of the bacterial species capable of producing pore-forming toxic molecules, the Gram-positive pathogen Staphylococcus aureus is one of the most notorious. S. aureus can produce seven different pore-forming protein toxins, all of which are believed to play a unique role in promoting the ability of the organism to cause disease in humans and other mammals. The most diverse of these pore-forming toxins, in terms of both functional activity and global representation within S. aureus clinical isolates, are the bicomponent leucocidins. From the first description of their activity on host immune cells over 100 years ago to the detailed investigations of their biochemical function today, the leucocidins remain at the forefront of S. aureus pathogenesis research initiatives. Study of their mode of action is of immediate interest in the realm of therapeutic agent design as well as for studies of bacterial pathogenesis. This review provides an updated perspective on our understanding of the S. aureus leucocidins and their function, specificity, and potential as therapeutic targets.
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25
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Badarau A, Rouha H, Malafa S, Logan DT, Håkansson M, Stulik L, Dolezilkova I, Teubenbacher A, Gross K, Maierhofer B, Weber S, Jägerhofer M, Hoffman D, Nagy E. Structure-function analysis of heterodimer formation, oligomerization, and receptor binding of the Staphylococcus aureus bi-component toxin LukGH. J Biol Chem 2014; 290:142-56. [PMID: 25371205 DOI: 10.1074/jbc.m114.598110] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The bi-component leukocidins of Staphylococcus aureus are important virulence factors that lyse human phagocytic cells and contribute to immune evasion. The γ-hemolysins (HlgAB and HlgCB) and Panton-Valentine leukocidin (PVL or LukSF) were shown to assemble from soluble subunits into membrane-bound oligomers on the surface of target cells, creating barrel-like pore structures that lead to cell lysis. LukGH is the most distantly related member of this toxin family, sharing only 30-40% amino acid sequence identity with the others. We observed that, unlike other leukocidin subunits, recombinant LukH and LukG had low solubility and were unable to bind to target cells, unless both components were present. Using biolayer interferometry and intrinsic tryptophan fluorescence we detected binding of LukH to LukG in solution with an affinity in the low nanomolar range and dynamic light scattering measurements confirmed formation of a heterodimer. We elucidated the structure of LukGH by x-ray crystallography at 2.8-Å resolution. This revealed an octameric structure that strongly resembles that reported for HlgAB, but with important structural differences. Structure guided mutagenesis studies demonstrated that three salt bridges, not found in other bi-component leukocidins, are essential for dimer formation in solution and receptor binding. We detected weak binding of LukH, but not LukG, to the cellular receptor CD11b by biolayer interferometry, suggesting that in common with other members of this toxin family, the S-component has the primary contact role with the receptor. These new insights provide the basis for novel strategies to counteract this powerful toxin and Staphylococcus aureus pathogenesis.
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Affiliation(s)
- Adriana Badarau
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Harald Rouha
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Stefan Malafa
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Derek T Logan
- SARomics Biostructures AB, Medicon Village, S-223 81 Lund, Sweden
| | - Maria Håkansson
- SARomics Biostructures AB, Medicon Village, S-223 81 Lund, Sweden
| | - Lukas Stulik
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Ivana Dolezilkova
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Astrid Teubenbacher
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Karin Gross
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Barbara Maierhofer
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Susanne Weber
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Michaela Jägerhofer
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - David Hoffman
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Eszter Nagy
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
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26
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Residues essential for Panton-Valentine leukocidin S component binding to its cell receptor suggest both plasticity and adaptability in its interaction surface. PLoS One 2014; 9:e92094. [PMID: 24643034 PMCID: PMC3958440 DOI: 10.1371/journal.pone.0092094] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 02/18/2014] [Indexed: 01/01/2023] Open
Abstract
Panton-Valentine leukocidin (PVL), a bicomponent staphylococcal leukotoxin, is involved in the poor prognosis of necrotizing pneumonia. The present study aimed to elucidate the binding mechanism of PVL and in particular its cell-binding domain. The class S component of PVL, LukS-PV, is known to ensure cell targeting and exhibits the highest affinity for the neutrophil membrane (Kd∼10−10 M) compared to the class F component of PVL, LukF-PV (Kd∼10−9 M). Alanine scanning mutagenesis was used to identify the residues involved in LukS-PV binding to the neutrophil surface. Nineteen single alanine mutations were performed in the rim domain previously described as implicated in cell membrane interactions. Positions were chosen in order to replace polar or exposed charged residues and according to conservation between leukotoxin class S components. Characterization studies enabled to identify a cluster of residues essential for LukS-PV binding, localized on two loops of the rim domain. The mutations R73A, Y184A, T244A, H245A and Y250A led to dramatically reduced binding affinities for both human leukocytes and undifferentiated U937 cells expressing the C5a receptor. The three-dimensional structure of five of the mutants was determined using X-ray crystallography. Structure analysis identified residues Y184 and Y250 as crucial in providing structural flexibility in the receptor-binding domain of LukS-PV.
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27
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Aman MJ, Adhikari RP. Staphylococcal bicomponent pore-forming toxins: targets for prophylaxis and immunotherapy. Toxins (Basel) 2014; 6:950-72. [PMID: 24599233 PMCID: PMC3968370 DOI: 10.3390/toxins6030950] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/22/2014] [Accepted: 02/26/2014] [Indexed: 01/09/2023] Open
Abstract
Staphylococccus aureus represents one of the most challenging human pathogens as well as a common colonizer of human skin and mucosal surfaces. S. aureus causes a wide range of diseases from skin and soft tissue infection (SSTI) to debilitating and life-threatening conditions such as osteomyelitis, endocarditis, and necrotizing pneumonia. The range of diseases reflects the remarkable diversity of the virulence factors produced by this pathogen, including surface antigens involved in the establishment of infection and a large number of toxins that mediate a vast array of cellular responses. The staphylococcal toxins are generally believed to have evolved to disarm the innate immune system, the first line of defense against this pathogen. This review focuses on recent advances on elucidating the biological functions of S. aureus bicomponent pore-forming toxins (BCPFTs) and their utility as targets for preventive and therapeutic intervention. These toxins are cytolytic to a variety of immune cells, primarily neutrophils, as well as cells with a critical barrier function. The lytic activity of BCPFTs towards immune cells implies a critical role in immune evasion, and a number of epidemiological studies and animal experiments relate these toxins to clinical disease, particularly SSTI and necrotizing pneumonia. Antibody-mediated neutralization of this lytic activity may provide a strategy for development of toxoid-based vaccines or immunotherapeutics for prevention or mitigation of clinical diseases. However, certain BCPFTs have been proposed to act as danger signals that may alert the immune system through an inflammatory response. The utility of a neutralizing vaccination strategy must be weighed against such immune-activating potential.
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Affiliation(s)
- M Javad Aman
- Integrated BioTherapeutics Inc., 21 Firstfield Rd., Gaithersburg, MD 20878, USA.
| | - Rajan P Adhikari
- Integrated BioTherapeutics Inc., 21 Firstfield Rd., Gaithersburg, MD 20878, USA.
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28
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Qu T, Feng Y, Jiang Y, Zhu P, Wei Z, Chen Y, Otto M, Yu Y. Whole genome analysis of a community-associated methicillin-resistant Staphylococcus aureus ST59 isolate from a case of human sepsis and severe pneumonia in China. PLoS One 2014; 9:e89235. [PMID: 24586619 PMCID: PMC3930696 DOI: 10.1371/journal.pone.0089235] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/16/2014] [Indexed: 12/12/2022] Open
Abstract
We report a case of necrotizing pneumonia in a young patient caused by community acquired-methicillin resistant Staphylococcus aureus (CA-MRSA) in a teaching hospital in the People's Republic of China. The patient had a typical clinical presentation and was successfully treated with antibiotics and intravenous immunoglobulin. A CA-MRSA strain, named SA268, was isolated from the blood of the patient. The isolate was susceptible to most antimicrobial agents, except cephalosporins, penicillins, and β-lactamase inhibitor combinations. Multi-locus sequence typing (MLST) assigned SA268 to ST59, a clone widely spread in eastern Asia. The strain was positive for Panton Valentine Leukocidin (PVL)-encoding genes and SCCmec type V. We sequenced the complete genome of the SA268 isolate. The genome of SA268 was almost identical to that of the Taiwanese ST59 CA-MRSA strains M013 and SA957. However, we observed several differences in gene composition, which included differences in the SCCmec element and several lipoprotein genes that were present in the Taiwanese strains but absent from SA268.
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Affiliation(s)
- Tingting Qu
- State Key Laboratory for Diagnosis and Treatment of Infectious Disease, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ye Feng
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yan Jiang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Peiqiong Zhu
- Department of Clinical Medicine, Zhejiang Medical College, Hangzhou, Zhejiang, China
| | - Zeqing Wei
- State Key Laboratory for Diagnosis and Treatment of Infectious Disease, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yan Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (YY); (MO)
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
- * E-mail: (YY); (MO)
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29
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Identification of a crucial residue required for Staphylococcus aureus LukAB cytotoxicity and receptor recognition. Infect Immun 2013; 82:1268-76. [PMID: 24379286 DOI: 10.1128/iai.01444-13] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The bicomponent leukotoxins produced by Staphylococcus aureus kill host immune cells through osmotic lysis by forming β-barrel pores in the host plasma membrane. The current model for bicomponent pore formation proposes that octameric pores, comprised of two separate secreted polypeptides (S and F subunits), are assembled from water-soluble monomers in the extracellular milieu and multimerize on target cell membranes. However, it has yet to be determined if all staphylococcal bicomponent leukotoxin family members exhibit these properties. In this study, we report that leukocidin A/B (LukAB), the most divergent member of the leukotoxin family, exists as a heterodimer in solution rather than two separate monomeric subunits. Notably, this property was found to be associated with enhanced toxin activity. LukAB also differs from the other bicomponent leukotoxins in that the S subunit (LukA) contains 33- and 10-amino-acid extensions at the N and C termini, respectively. Truncation mutagenesis revealed that deletion of the N terminus resulted in a modest increase in LukAB cytotoxicity, whereas the deletion of the C terminus rendered the toxin inactive. Within the C terminus of LukA, we identified a glutamic acid at position 323 that is critical for LukAB cytotoxicity. Furthermore, we discovered that this residue is conserved and required for the interaction between LukAB and its cellular target CD11b. Altogether, these findings provide an in-depth analysis of how LukAB targets neutrophils and identify novel targets suitable for the rational design of anti-LukAB inhibitors.
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Valour F, Chebib N, Gillet Y, Reix P, Laurent F, Chidiac C, Ferry T. [Staphylococcus aureus broncho-pulmonary infections]. REVUE DE PNEUMOLOGIE CLINIQUE 2013; 69:368-382. [PMID: 24183294 DOI: 10.1016/j.pneumo.2013.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 07/30/2013] [Accepted: 08/05/2013] [Indexed: 06/02/2023]
Abstract
Staphylococcus aureus accounts for 2-5% of the etiologies of community-acquired pneumonia. These infections occur mainly in elderly patients with comorbidity, after a respiratory viral infection. S. aureus could also be responsible for necrotizing pneumonia, which occurs in young subjects, also after flu. Necrotizing pneumonia are associated with the production of a particular staphylococcal toxin called Panton-Valentine leukocidin, responsible for pulmonary focal necrosis, occurrence haemoptysis, leucopenia, and death. In Europe, these strains are still predominantly sensitive to anti-staphylococcal penicillin, which must be used at high dosage intravenously in combination with an antibiotic that reduces toxin production such as clindamycin, and intravenous immunoglobulin in severe cases. The mortality rate is estimated at 50%. In addition, S. aureus is one of the pathogens involved in early respiratory infections in cystic fibrosis patients, in whom methicillin resistance plays an important prognostic role. However, the involvement of S. aureus in COPD exacerbations is rare. Finally, S. aureus represents 20 to 30% of cases of hospital-acquired pneumonia, including ventilator-associated pneumonia. In these cases, methicillin-resistance is common and requires the use of glycopeptides or linezolid. The place of new anti-staphylococcal antibiotics such as new generation cephalosporins or tigecyclin remains to be defined.
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Affiliation(s)
- F Valour
- Service des maladies infectieuses et tropicales, hospices civils de Lyon, hôpital de la Croix-Rousse, groupement hospitalier Nord, 103, Grande-Rue-de-la-Croix-Rousse, 69004 Lyon, France; Université Claude-Bernard Lyon 1, 69008 Lyon, France; Inserm U1111, CNRS UMR5308, ENS de lyon, UCBL1, Centre international de recherche en infectiologie (CIRI), 69007 Lyon, France; Centre national de référence des staphylocoques, hospices civils de Lyon, 69008 Lyon, France
| | - N Chebib
- Service des maladies infectieuses et tropicales, hospices civils de Lyon, hôpital de la Croix-Rousse, groupement hospitalier Nord, 103, Grande-Rue-de-la-Croix-Rousse, 69004 Lyon, France
| | - Y Gillet
- Université Claude-Bernard Lyon 1, 69008 Lyon, France; Inserm U1111, CNRS UMR5308, ENS de lyon, UCBL1, Centre international de recherche en infectiologie (CIRI), 69007 Lyon, France; Centre national de référence des staphylocoques, hospices civils de Lyon, 69008 Lyon, France; Service d'urgences pédiatriques, hospices civils de Lyon, hôpital Femme-Mère-Enfant, 69500 Bron, France
| | - P Reix
- Université Claude-Bernard Lyon 1, 69008 Lyon, France; Service de pneumologie, allergologie, mucoviscidose, hospices civils de Lyon, hôpital Femme-Mère-Enfant, 69500 Bron, France
| | - F Laurent
- Université Claude-Bernard Lyon 1, 69008 Lyon, France; Inserm U1111, CNRS UMR5308, ENS de lyon, UCBL1, Centre international de recherche en infectiologie (CIRI), 69007 Lyon, France; Centre national de référence des staphylocoques, hospices civils de Lyon, 69008 Lyon, France; Laboratoire de bactériologie, hospices civils de Lyon, groupement hospitalier Nord, 69004 Lyon, France
| | - C Chidiac
- Service des maladies infectieuses et tropicales, hospices civils de Lyon, hôpital de la Croix-Rousse, groupement hospitalier Nord, 103, Grande-Rue-de-la-Croix-Rousse, 69004 Lyon, France; Université Claude-Bernard Lyon 1, 69008 Lyon, France; Inserm U1111, CNRS UMR5308, ENS de lyon, UCBL1, Centre international de recherche en infectiologie (CIRI), 69007 Lyon, France; Centre national de référence des staphylocoques, hospices civils de Lyon, 69008 Lyon, France
| | - T Ferry
- Service des maladies infectieuses et tropicales, hospices civils de Lyon, hôpital de la Croix-Rousse, groupement hospitalier Nord, 103, Grande-Rue-de-la-Croix-Rousse, 69004 Lyon, France; Université Claude-Bernard Lyon 1, 69008 Lyon, France; Inserm U1111, CNRS UMR5308, ENS de lyon, UCBL1, Centre international de recherche en infectiologie (CIRI), 69007 Lyon, France; Centre national de référence des staphylocoques, hospices civils de Lyon, 69008 Lyon, France.
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DuMont AL, Torres VJ. Cell targeting by the Staphylococcus aureus pore-forming toxins: it's not just about lipids. Trends Microbiol 2013; 22:21-7. [PMID: 24231517 DOI: 10.1016/j.tim.2013.10.004] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/11/2013] [Accepted: 10/16/2013] [Indexed: 01/12/2023]
Abstract
Staphylococcus aureus employs numerous pore-forming cytotoxins to injure host immune cells and promote infection. Until recently, it was unclear how these cytotoxins targeted specific cell types for lysis. Membrane lipids were initially postulated to be cytotoxin receptor candidates. However, the cell-type specificity and species-dependent targeting of these toxins did not support lipids as sole receptors. The recent identification of proteinaceous receptors for several S. aureus cytotoxins now provides an explanation for the observed tropism. These findings also have important implications for the implementation of animal models to study S. aureus pathogenesis, and for the development of novel therapeutics.
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Affiliation(s)
- Ashley L DuMont
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA.
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Kong L, Harrington L, Li Q, Cheley S, Davis BG, Bayley H. Single-molecule interrogation of a bacterial sugar transporter allows the discovery of an extracellular inhibitor. Nat Chem 2013; 5:651-9. [DOI: 10.1038/nchem.1695] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 05/24/2013] [Indexed: 11/09/2022]
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Karauzum H, Adhikari RP, Sarwar J, Devi VS, Abaandou L, Haudenschild C, Mahmoudieh M, Boroun AR, Vu H, Nguyen T, Warfield KL, Shulenin S, Aman MJ. Structurally designed attenuated subunit vaccines for S. aureus LukS-PV and LukF-PV confer protection in a mouse bacteremia model. PLoS One 2013; 8:e65384. [PMID: 23762356 PMCID: PMC3676412 DOI: 10.1371/journal.pone.0065384] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/24/2013] [Indexed: 01/29/2023] Open
Abstract
Previous efforts towards S. aureus vaccine development have largely focused on cell surface antigens to induce opsonophagocytic killing aimed at providing sterile immunity, a concept successfully applied to other Gram-positive pathogens such as Streptococcus pneumoniae. However, these approaches have largely failed, possibly in part due to the remarkable diversity of the staphylococcal virulence factors such as secreted immunosuppressive and tissue destructive toxins. S. aureus produces several pore-forming toxins including the single subunit alpha hemolysin as well as bicomponent leukotoxins such as Panton-Valentine leukocidin (PVL), gamma hemolysins (Hlg), and LukED. Here we report the generation of highly attenuated mutants of PVL subunits LukS-PV and LukF-PV that were rationally designed, based on an octameric structural model of the toxin, to be deficient in oligomerization. The attenuated subunit vaccines were highly immunogenic and showed significant protection in a mouse model of S. aureus USA300 sepsis. Protection against sepsis was also demonstrated by passive transfer of rabbit immunoglobulin raised against LukS-PV. Antibodies to LukS-PV inhibited the homologous oligomerization of LukS-PV with LukF-PV as well heterologous oligomerization with HlgB. Importantly, immune sera from mice vaccinated with the LukS mutant not only inhibited the PMN lytic activity produced by the PVL-positive USA300 but also blocked PMN lysis induced by supernatants of PVL-negative strains suggesting a broad protective activity towards other bicomponent toxins. These findings strongly support the novel concept of an anti-virulence, toxin-based vaccine intended for prevention of clinical S. aureus invasive disease, rather than achieving sterile immunity. Such a multivalent vaccine may include attenuated leukotoxins, alpha hemolysin, and superantigens.
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Affiliation(s)
- Hatice Karauzum
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Rajan P. Adhikari
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Jawad Sarwar
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - V. Sathya Devi
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Laura Abaandou
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | | | - Mahta Mahmoudieh
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Atefeh R. Boroun
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Hong Vu
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Tam Nguyen
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Kelly L. Warfield
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Sergey Shulenin
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - M. Javad Aman
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
- * E-mail:
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p-Sulfonato-calix[n]arenes inhibit staphylococcal bicomponent leukotoxins by supramolecular interactions. Biochem J 2013; 450:559-71. [PMID: 23282185 DOI: 10.1042/bj20121628] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PVL (Panton-Valentine leukocidin) and other Staphylococcus aureus β-stranded pore-forming toxins are important virulence factors involved in various pathologies that are often necrotizing. The present study characterized leukotoxin inhibition by selected SCns (p-sulfonato-calix[n]arenes): SC4, SC6 and SC8. These chemicals have no toxic effects on human erythrocytes or neutrophils, and some are able to inhibit both the activity of and the cell lysis by leukotoxins in a dose-dependent manner. Depending on the type of leukotoxins and SCns, flow cytometry revealed IC50 values of 6-22 μM for Ca2+ activation and of 2-50 μM for cell lysis. SCns were observed to affect membrane binding of class S proteins responsible for cell specificity. Electrospray MS and surface plasmon resonance established supramolecular interactions (1:1 stoichiometry) between SCns and class S proteins in solution, but not class F proteins. The membrane-binding affinity of S proteins was Kd=0.07-6.2 nM. The binding ability was completely abolished by SCns at different concentrations according to the number of benzenes (30-300 μM; SC8>SC6≫SC4). The inhibitory properties of SCns were also observed in vivo in a rabbit model of PVL-induced endophthalmitis. These calixarenes may represent new therapeutic avenues aimed at minimizing inflammatory reactions and necrosis due to certain virulence factors.
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Affiliation(s)
| | - Sergey M. Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, U.S.A
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Alessandrini A, Viero G, Dalla Serra M, Prévost G, Facci P. γ-Hemolysin oligomeric structure and effect of its formation on supported lipid bilayers: an AFM investigation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:405-11. [PMID: 23036932 DOI: 10.1016/j.bbamem.2012.09.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/05/2012] [Accepted: 09/25/2012] [Indexed: 11/28/2022]
Abstract
γ-Hemolysins are bicomponent β-barrel pore forming toxins produced by Staphylococcus aureus as water-soluble monomers, which assemble into oligomeric pores on the surface of lipid bilayers. Here, after investigating the oligomeric structure of γ-hemolysins on supported lipid bilayers (SLBs) by atomic force microscopy (AFM), we studied the effect produced by this toxin on the structure of SLBs. We found that oligomeric structures with different number of monomers can assemble on the lipid bilayer being the octameric form the stablest one. Moreover, in this membrane model we found that γ-hemolysins can form clusters of oligomers inducing a curvature in the lipid bilayer, which could probably enhance the aggressiveness of these toxins at high concentrations.
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Affiliation(s)
- Andrea Alessandrini
- Centro S3, CNR-Istituto di Nanoscienze, Via Campi 213/A, 41125 Modena, Italy.
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Nishiyama A, Isobe H, Iwao Y, Takano T, Hung WC, Taneike I, Nakagawa S, Dohmae S, Iwakura N, Yamamoto T. Accumulation of staphylococcal Panton-Valentine leukocidin in the detergent-resistant membrane microdomains on the target cells is essential for its cytotoxicity. ACTA ACUST UNITED AC 2012; 66:343-52. [PMID: 22924956 DOI: 10.1111/j.1574-695x.2012.01027.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 07/24/2012] [Accepted: 07/27/2012] [Indexed: 12/23/2022]
Abstract
The mechanisms for the cytotoxicity of staphylococcal Panton-Valentine leukocidin (PVL), a pore-forming toxin consisting of LukS-PV and LukF-PV, in human immune cells are still unclear. Because LukS-PV binds to ganglioside GM1, a constituent of detergent-resistant membrane microdomains (DRMs) of the plasma membrane, the role of DRMs in PVL cytotoxicity was examined in human polymorphonuclear neutrophils (PMNs), monocytes, HL-60 cells, and THP-1 cells. PVL binding capacities in HL-60 and THP-1 cells were higher than those in PMNs and monocytes; however, the PVL concentration to obtain more than 80% cell lysis in HL-60 cells was 10 times higher than that in PMNs and PVL even at such concentration induced < 10% cell lysis in THP-1 cells. After incubation of PMNs with LukS-PV, more than 90% of LukS-PV bound to the detergent-soluble membranes. Subsequent incubation with LukF-PV at 4 °C induced the accumulation of more than 70% of PVL components and 170- to 220-kDa complex formation in DRMs in an actin-independent manner. However, only 30% of PVL was found, and complex formation was under detectable level in DRMs in HL-60 cells. PVL did not accumulate in DRMs in THP-1 cells. Our observations strongly indicate that PVL accumulation in DRMs is essential for PVL cytotoxicity.
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Affiliation(s)
- Akihito Nishiyama
- Division of Bacteriology, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Adhikari RP, Ajao AO, Aman MJ, Karauzum H, Sarwar J, Lydecker AD, Johnson JK, Nguyen C, Chen WH, Roghmann MC. Lower antibody levels to Staphylococcus aureus exotoxins are associated with sepsis in hospitalized adults with invasive S. aureus infections. J Infect Dis 2012; 206:915-23. [PMID: 22807524 DOI: 10.1093/infdis/jis462] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Staphylococcus aureus has numerous virulence factors, including exotoxins that may increase the severity of infection. This study was aimed at assessing whether preexisting antibodies to S. aureus toxins are associated with a lower risk of sepsis in adults with S. aureus infection complicated by bacteremia. METHODS We prospectively identified adults with S. aureus infection from 4 hospitals in Baltimore, MD, in 2009–2011. We obtained serum samples from prior to or at presentation of S. aureus bacteremia to measure total immunoglobulin G (IgG) and IgG antibody levels to 11 S. aureus exotoxins. Bacterial isolates were tested for the genes encoding S. aureus exotoxins using polymerase chain reaction (PCR). RESULTS One hundred eligible subjects were included and 27 of them developed sepsis. When adjusted for total IgG levels and stratified for the presence of toxin in the infecting isolate as appropriate, the risk of sepsis was significantly lower in those patients with higher levels of IgG against α-hemolysin (Hla), δ-hemolysin (Hld), Panton Valentine leukocidin (PVL), staphylococcal enterotoxin C-1 (SEC-1), and phenol-soluble modulin α3 (PSM-α3). CONCLUSIONS Our results suggest that higher antibody levels against Hla, Hld, PVL, SEC-1, and PSM-α3 may protect against sepsis in patients with invasive S. aureus infections.
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Ma X, Chang W, Zhang C, Zhou X, Yu F. Staphylococcal Panton-Valentine leukocidin induces pro-inflammatory cytokine production and nuclear factor-kappa B activation in neutrophils. PLoS One 2012; 7:e34970. [PMID: 22529963 PMCID: PMC3329533 DOI: 10.1371/journal.pone.0034970] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 03/08/2012] [Indexed: 12/21/2022] Open
Abstract
Panton-Valentine leukocidin (PVL) is a cytotoxin secreted by Staphylococcus aureus and associated with severe necrotizing infections. PVL targets polymorphonuclear leukocytes, especially neutrophils, which are the first line of defense against infections. Although PVL can induce neutrophil death by necrosis or apoptosis, the specific inflammatory responses of neutrophils to this toxin are unclear. In this study, both in vivo and in vitro studies demonstrated that recombinant PVL has an important cytotoxic role in human neutrophils, leading to apoptosis at low concentrations and necrosis at high concentrations. Recombinant PVL also increased the levels of pro-inflammatory cytokine secretion from neutrophils. The up-regulation of pro-inflammatory cytokines was due to nuclear factor-kappa B (NF-κB) activation induced by PVL. Moreover, blocking NF-κB inhibited the production of inflammatory cytokines. To test the role of neutrophil immune responses during the pathogenesis of PVL-induced acute lung injury, we used immunocompetent or neutropenic rabbits to develop a model of necrotizing pneumonia. Immunocompetent rabbits challenged with PVL demonstrated increased inflammation containing neutrophilic infiltrates. In addition, there were elevated levels of inflammatory cytokines (IL-6, IL-8, TNF-α and IL-10) and NF-κB in the lung homogenate. In contrast, the lung tissues from neutropenic rabbits contained mild or moderate inflammation, and the levels of inflammatory cytokines and NF-κB increased only slightly. Data from the current study support growing evidence that neutrophils play an important role in the pathogenesis of PVL-induced tissue injury and inflammation. PVL can stimulate neutrophils to release pro-inflammatory mediators, thereby causing an acute inflammatory response. The ability of PVL to induce inflammatory cytokine release may be associated with the activation of NF-κB or its pore-forming properties.
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Affiliation(s)
- Xiaoling Ma
- Department of Laboratory Medicine, Anhui Provincial Hospital, Anhui Medical University, Hefei, China.
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40
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Perret M, Badiou C, Lina G, Burbaud S, Benito Y, Bes M, Cottin V, Couzon F, Juruj C, Dauwalder O, Goutagny N, Diep BA, Vandenesch F, Henry T. Cross-talk between Staphylococcus aureus leukocidins-intoxicated macrophages and lung epithelial cells triggers chemokine secretion in an inflammasome-dependent manner. Cell Microbiol 2012; 14:1019-36. [DOI: 10.1111/j.1462-5822.2012.01772.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Abstract
The use of nanopores is a powerful new frontier in single-molecule sciences. Nanopores have been used effectively in exploring various biophysical features of small polypeptides and proteins, such as their folding state and structure, ligand interactions, and enzymatic activity. In particular, the α-hemolysin (αHL) protein pore has been used extensively for the detection, characterization, and analysis of polypeptides because this protein nanopore is highly robust, versatile, and tractable under various experimental conditions. Inspired by the mechanisms of protein translocation across the outer membrane translocases of mitochondria, we have shown the ability to use nanopore-probe techniques in controlling a single protein using engineered αHL pores. Here, we provide a detailed protocol for the preparation of αHL protein nanopores. Moreover, we demonstrate that placing attractive electrostatic traps is instrumental in tackling single-molecule stochastic sensing of folded proteins.
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Community-acquired necrotizing pneumonia due to methicillin-sensitive Staphylococcus aureus secreting Panton-Valentine leukocidin: a review of case reports. Ann Intensive Care 2011; 1:52. [PMID: 22192614 PMCID: PMC3259061 DOI: 10.1186/2110-5820-1-52] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 12/22/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Community-acquired necrotizing pneumonia caused by Panton-Valentine leukocidin (PVL)-secreting Staphylococcus aureus is a highly lethal infection that mainly affects healthy children and young adults. Both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) may carry the PVL-phage, but the majority of publications relate to community-associated methicillin-resistant S. aureus (CA-MRSA) or mixed patient groups. This study focuses on necrotizing pneumonia due to methicillin-sensitive S. aureus strains, with the purpose to determine factors associated with outcome. METHODS We report a patient with PVL secreting MSSA necrotizing pneumonia and performed a systematic review of similar case in the literature. We analyzed factors associated with outcome. RESULTS A total of 32 patient descriptions were retained for analysis. Septic shock (p = 0.007), influenza-like prodrome (p = 0.02), and the absence of a previous skin and soft-tissue infection (p = 0.024) were associated with fatal outcome. In multivariate analysis, influenza-like prodrome (odds ratio (OR), 7.44; 95% confidence interval (CI), 1.24-44.76; p = 0.028) and absence of previous skin and soft-tissue infection (OR, 0.09; 95% CI, 0.01-0.86; p = 0.036) remained significant predictors of death. CONCLUSIONS Influenza-like prodrome may be predictive of adverse outcome in PVL-secreting MSSA necrotizing pneumonia. In contrast, previous skin and soft-tissue infection may be associated with improved prognosis.
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Parker D, Prince A. Immunopathogenesis of Staphylococcus aureus pulmonary infection. Semin Immunopathol 2011; 34:281-97. [PMID: 22037948 DOI: 10.1007/s00281-011-0291-7] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 10/14/2011] [Indexed: 01/23/2023]
Abstract
Staphylococcus aureus is a common human pathogen highly evolved as both a component of the commensal flora and as a major cause of invasive infection. Severe respiratory infection due to staphylococci has been increasing due to the prevalence of more virulent USA300 CA-MRSA strains in the general population. The ability of S. aureus to adapt to the milieu of the respiratory tract has facilitated its emergence as a respiratory pathogen. Its metabolic versatility, the ability to scavenge iron, coordinate gene expression, and the horizontal acquisition of useful genetic elements have all contributed to its success as a component of the respiratory flora, in hospitalized patients, as a complication of influenza and in normal hosts. The expression of surface adhesins facilitates its persistence in the airways. In addition, the highly sophisticated interactions of the multiple S. aureus virulence factors, particularly the α-hemolysin and protein A, with diverse immune effectors in the lung such as ADAM10, TNFR1, EGFR, immunoglobulin, and complement all contribute to the pathogenesis of staphylococcal pneumonia.
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Affiliation(s)
- Dane Parker
- Department of Pediatrics, Columbia University, New York, NY, USA
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44
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Crystal structure of the octameric pore of staphylococcal γ-hemolysin reveals the β-barrel pore formation mechanism by two components. Proc Natl Acad Sci U S A 2011; 108:17314-9. [PMID: 21969538 DOI: 10.1073/pnas.1110402108] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcal γ-hemolysin is a bicomponent pore-forming toxin composed of LukF and Hlg2. These proteins are expressed as water-soluble monomers and then assemble into the oligomeric pore form on the target cell. Here, we report the crystal structure of the octameric pore form of γ-hemolysin at 2.5 Å resolution, which is the first high-resolution structure of a β-barrel transmembrane protein composed of two proteins reported to date. The octameric assembly consists of four molecules of LukF and Hlg2 located alternately in a circular pattern, which explains the biochemical data accumulated over the past two decades. The structure, in combination with the monomeric forms, demonstrates the elaborate molecular machinery involved in pore formation by two different molecules, in which interprotomer electrostatic interactions using loops connecting β2 and β3 (loop A: Asp43-Lys48 of LukF and Lys37-Lys43 of Hlg2) play pivotal roles as the structural determinants for assembly through unwinding of the N-terminal β-strands (amino-latch) of the adjacent protomer, releasing the transmembrane stem domain folded into a β-sheet in the monomer (prestem), and interaction with the adjacent protomer.
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Bien J, Sokolova O, Bozko P. Characterization of Virulence Factors of Staphylococcus aureus: Novel Function of Known Virulence Factors That Are Implicated in Activation of Airway Epithelial Proinflammatory Response. J Pathog 2011; 2011:601905. [PMID: 22567334 PMCID: PMC3335658 DOI: 10.4061/2011/601905] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 06/23/2011] [Accepted: 07/15/2011] [Indexed: 12/04/2022] Open
Abstract
Airway epithelial cells play a major role in initiating inflammation in response to bacterial pathogens. S. aureus is an important pathogen associated with activation of diverse types of infection characterized by inflammation dominated by polymorphonuclear leukocytes. This bacterium frequently causes lung infection, which is attributed to virulence factors. Many of virulence determinants associated with S. aureus-mediated lung infection have been known for several years. In this paper, we discuss recent advances in our understanding of known virulence factors implicated in pneumonia. We anticipate that better understanding of novel functions of known virulence factors could open the way to regulate inflammatory reactions of the epithelium and to develop effective strategies to treat S. aureus-induced airway diseases.
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Affiliation(s)
- Justyna Bien
- Witold Stefanski Institute of Parasitology of the Polish Academy of Sciences, Twarda Street 51/55, 00-818 Warsaw, Poland
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46
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Cheneke BR, van den Berg B, Movileanu L. Analysis of gating transitions among the three major open states of the OpdK channel. Biochemistry 2011; 50:4987-97. [PMID: 21548584 PMCID: PMC3107985 DOI: 10.1021/bi200454j] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OpdK is an outer membrane protein of the pathogenic bacterium Pseudomonas aeruginosa. The recent crystal structure of this protein revealed a monomeric, 18-stranded β-barrel with a kidney-shaped pore, whose constriction features a diameter of 8 Å. Using systematic single-channel electrical recordings of this protein pore reconstituted into planar lipid bilayers under a broad range of ion concentrations, we were able to probe its discrete gating kinetics involving three major and functionally distinct conformations, in which a dominant open substate O(2) is accompanied by less thermodynamically stable substates O(1) and O(3). Single-channel electrical data enabled us to determine the alterations in the energetics and kinetics of the OpdK protein when experimental conditions were changed. In the future, such a semiquantitative analysis might provide a better understanding on the dynamics of current fluctuations of other β-barrel membrane protein channels.
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Affiliation(s)
- Belete R. Cheneke
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Bert van den Berg
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
- Syracuse Biomaterials Institute, Syracuse University, 121 Link Hall, Syracuse, New York 13244, USA
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Hammerstein AF, Jayasinghe L, Bayley H. Subunit dimers of alpha-hemolysin expand the engineering toolbox for protein nanopores. J Biol Chem 2011; 286:14324-34. [PMID: 21324910 PMCID: PMC3077633 DOI: 10.1074/jbc.m111.218164] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 02/10/2011] [Indexed: 12/27/2022] Open
Abstract
Staphylococcal α-hemolysin (αHL) forms a heptameric pore that features a 14-stranded transmembrane β-barrel. We attempted to force the αHL pore to adopt novel stoichiometries by oligomerizing subunit dimers generated by in vitro transcription and translation of a tandem gene. However, in vitro transcription and translation also produced truncated proteins, monomers, that were preferentially incorporated into oligomers. These oligomers were shown to be functional heptamers by single-channel recording and had a similar mobility to wild-type heptamers in SDS-polyacrylamide gels. Purified full-length subunit dimers were then prepared by using His-tagged protein. Again, single-channel recording showed that oligomers made from these dimers are functional heptamers, implying that one or more subunits are excluded from the central pore. Therefore, the αHL pore resists all structures except those that possess seven subunits immediately surrounding the central axis. Although we were not able to change the stoichiometry of the central pore of αHL by the concatenation of subunits, we extended our findings to prepare pores containing one subunit dimer and five monomers and purified them by SDS-PAGE. Two half-chelating ligands were then installed at adjacent sites, one on each subunit of the dimer. Single-channel recording showed that pores formed from this construct formed complexes with divalent metal ions in a similar fashion to pores containing two half-chelating ligands on the same subunit, confirming that the oligomers had assembled with seven subunits around the central lumen. The ability to incorporate subunit dimers into αHL pores increases the range of structures that can be obtained from engineered protein nanopores.
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Affiliation(s)
- Anne F. Hammerstein
- From the Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Lakmal Jayasinghe
- From the Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Hagan Bayley
- From the Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
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Kitadokoro K, Nishimura K, Kamitani S, Fukui-Miyazaki A, Toshima H, Abe H, Kamata Y, Sugita-Konishi Y, Yamamoto S, Karatani H, Horiguchi Y. Crystal structure of Clostridium perfringens enterotoxin displays features of beta-pore-forming toxins. J Biol Chem 2011; 286:19549-55. [PMID: 21489981 DOI: 10.1074/jbc.m111.228478] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) is a cause of food poisoning and is considered a pore-forming toxin, which damages target cells by disrupting the selective permeability of the plasma membrane. However, the pore-forming mechanism and the structural characteristics of the pores are not well documented. Here, we present the structure of CPE determined by x-ray crystallography at 2.0 Å. The overall structure of CPE displays an elongated shape, composed of three distinct domains, I, II, and III. Domain I corresponds to the region that was formerly referred to as C-CPE, which is responsible for binding to the specific receptor claudin. Domains II and III comprise a characteristic module, which resembles those of β-pore-forming toxins such as aerolysin, C. perfringens ε-toxin, and Laetiporus sulfureus hemolytic pore-forming lectin. The module is mainly made up of β-strands, two of which span its entire length. Domain II and domain III have three short β-strands each, by which they are distinguished. In addition, domain II has an α-helix lying on the β-strands. The sequence of amino acids composing the α-helix and preceding β-strand demonstrates an alternating pattern of hydrophobic residues that is characteristic of transmembrane domains forming β-barrel-made pores. These structural features imply that CPE is a β-pore-forming toxin. We also hypothesize that the transmembrane domain is inserted into the membrane upon the buckling of the two long β-strands spanning the module, a mechanism analogous to that of the cholesterol-dependent cytolysins.
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Affiliation(s)
- Kengo Kitadokoro
- Graduate School of Science and Technology, Department of Biomolecular Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan
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Zivkovic A, Sharif O, Stich K, Doninger B, Biaggio M, Colinge J, Bilban M, Mesteri I, Hazemi P, Lemmens-Gruber R, Knapp S. TLR 2 and CD14 Mediate Innate Immunity and Lung Inflammation to Staphylococcal Panton–Valentine Leukocidin In Vivo. THE JOURNAL OF IMMUNOLOGY 2010; 186:1608-17. [DOI: 10.4049/jimmunol.1001665] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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50
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Panton-Valentine leucocidin and severe Staphylococcus aureus infections of the skin: sole culprit or does it have accomplices? Curr Opin Infect Dis 2010; 24:97-9. [PMID: 21169830 DOI: 10.1097/qco.0b013e3283431468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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