1
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Abrahamsen HL, Sanford TC, Collamore CE, Johnstone BA, Coyne MJ, García-Bayona L, Christie MP, Evans JC, Farrand AJ, Flores K, Morton CJ, Parker MW, Comstock LE, Tweten RK. Distant relatives of a eukaryotic cell-specific toxin family evolved a complement-like mechanism to kill bacteria. Nat Commun 2024; 15:5028. [PMID: 38866748 PMCID: PMC11169675 DOI: 10.1038/s41467-024-49103-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/22/2024] [Indexed: 06/14/2024] Open
Abstract
Cholesterol-dependent cytolysins (CDCs) comprise a large family of pore-forming toxins produced by Gram-positive bacteria, which are used to attack eukaryotic cells. Here, we functionally characterize a family of 2-component CDC-like (CDCL) toxins produced by the Gram-negative Bacteroidota that form pores by a mechanism only described for the mammalian complement membrane attack complex (MAC). We further show that the Bacteroides CDCLs are not eukaryotic cell toxins like the CDCs, but instead bind to and are proteolytically activated on the surface of closely related species, resulting in pore formation and cell death. The CDCL-producing Bacteroides is protected from the effects of its own CDCL by the presence of a surface lipoprotein that blocks CDCL pore formation. These studies suggest a prevalent mode of bacterial antagonism by a family of two-component CDCLs that function like mammalian MAC and that are wide-spread in the gut microbiota of diverse human populations.
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Affiliation(s)
- Hunter L Abrahamsen
- Department of Microbiology & Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Tristan C Sanford
- Department of Microbiology & Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Casie E Collamore
- Department of Microbiology & Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Bronte A Johnstone
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Michael J Coyne
- Duchossois Family Institute and Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Leonor García-Bayona
- Duchossois Family Institute and Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Michelle P Christie
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Jordan C Evans
- Department of Microbiology & Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Wheeler Bio, Oklahoma City, OK, 73104, USA
| | - Allison J Farrand
- Department of Microbiology & Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Wheeler Bio, Oklahoma City, OK, 73104, USA
| | - Katia Flores
- Duchossois Family Institute and Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Craig J Morton
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
- CSIRO Biomedical Manufacturing Program, Clayton, VIC, 3168, Australia
| | - Michael W Parker
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
- Australian Cancer Research Foundation Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, VIC, 2065, Australia.
| | - Laurie E Comstock
- Duchossois Family Institute and Department of Microbiology, University of Chicago, Chicago, IL, USA.
| | - Rodney K Tweten
- Department of Microbiology & Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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2
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Gigon L, Müller P, Haenni B, Iacovache I, Barbo M, Gosheva G, Yousefi S, Soragni A, von Ballmoos C, Zuber B, Simon HU. Membrane damage by MBP-1 is mediated by pore formation and amplified by mtDNA. Cell Rep 2024; 43:114084. [PMID: 38583154 DOI: 10.1016/j.celrep.2024.114084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/28/2023] [Accepted: 03/25/2024] [Indexed: 04/09/2024] Open
Abstract
Eosinophils play a crucial role in host defense while also contributing to immunopathology through the release of inflammatory mediators. Characterized by distinctive cytoplasmic granules, eosinophils securely store and rapidly release various proteins exhibiting high toxicity upon extracellular release. Among these, major basic protein 1 (MBP-1) emerges as an important mediator in eosinophil function against pathogens and in eosinophil-associated diseases. While MBP-1 targets both microorganisms and host cells, its precise mechanism remains elusive. We demonstrate that formation of small pores by MBP-1 in lipid bilayers induces membrane permeabilization and disrupts potassium balance. Additionally, we reveal that mitochondrial DNA (mtDNA) present in eosinophil extracellular traps (EETs) amplifies MBP-1 toxic effects, underscoring the pivotal role of mtDNA in EETs. Furthermore, we present evidence indicating that absence of CpG methylation in mtDNA contributes to the regulation of MBP-1-mediated toxicity. Taken together, our data suggest that the mtDNA scaffold within extracellular traps promotes MBP-1 toxicity.
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Affiliation(s)
- Lea Gigon
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland
| | - Philipp Müller
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Beat Haenni
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland
| | - Ioan Iacovache
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland
| | - Maruša Barbo
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland; Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Gordana Gosheva
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland; Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Shida Yousefi
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland
| | - Alice Soragni
- Department of Orthopedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Christoph von Ballmoos
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland
| | - Hans-Uwe Simon
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland; Institute of Biochemistry, Brandenburg Medical School, 16816 Neuruppin, Germany.
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3
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Kulma M, Šakanović A, Bedina-Zavec A, Caserman S, Omersa N, Šolinc G, Orehek S, Hafner-Bratkovič I, Kuhar U, Slavec B, Krapež U, Ocepek M, Kobayashi T, Kwiatkowska K, Jerala R, Podobnik M, Anderluh G. Sequestration of membrane cholesterol by cholesterol-binding proteins inhibits SARS-CoV-2 entry into Vero E6 cells. Biochem Biophys Res Commun 2024; 716:149954. [PMID: 38704887 DOI: 10.1016/j.bbrc.2024.149954] [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: 02/13/2024] [Revised: 03/26/2024] [Accepted: 04/15/2024] [Indexed: 05/07/2024]
Abstract
Membrane lipids and proteins form dynamic domains crucial for physiological and pathophysiological processes, including viral infection. Many plasma membrane proteins, residing within membrane domains enriched with cholesterol (CHOL) and sphingomyelin (SM), serve as receptors for attachment and entry of viruses into the host cell. Among these, human coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), use proteins associated with membrane domains for initial binding and internalization. We hypothesized that the interaction of lipid-binding proteins with CHOL in plasma membrane could sequestrate lipids and thus affect the efficiency of virus entry into host cells, preventing the initial steps of viral infection. We have prepared CHOL-binding proteins with high affinities for lipids in the plasma membrane of mammalian cells. Binding of the perfringolysin O domain four (D4) and its variant D4E458L to membrane CHOL impaired the internalization of the receptor-binding domain of the SARS-CoV-2 spike protein and the pseudovirus complemented with the SARS-CoV-2 spike protein. SARS-CoV-2 replication in Vero E6 cells was also decreased. Overall, our results demonstrate that the integrity of CHOL-rich membrane domains and the accessibility of CHOL in the membrane play an essential role in SARS-CoV-2 cell entry.
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Affiliation(s)
- Magdalena Kulma
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Aleksandra Šakanović
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Apolonija Bedina-Zavec
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Simon Caserman
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Neža Omersa
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Gašper Šolinc
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Sara Orehek
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Iva Hafner-Bratkovič
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; EN-FIST Centre of Excellence, Trg Osvobodilne Fronte 13, 1000, Ljubljana, Slovenia
| | - Urška Kuhar
- Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000, Ljubljana, Slovenia
| | - Brigita Slavec
- Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000, Ljubljana, Slovenia
| | - Uroš Krapež
- Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000, Ljubljana, Slovenia
| | - Matjaž Ocepek
- Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000, Ljubljana, Slovenia
| | - Toshihide Kobayashi
- Lipid Biology Laboratory, RIKEN, 2-1, Hirosawa, Wako-shi, Saitama, 351-0198, Japan; UMR 7021 CNRS, Université de Strasbourg, F-67401, Illkirch, France
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Roman Jerala
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; EN-FIST Centre of Excellence, Trg Osvobodilne Fronte 13, 1000, Ljubljana, Slovenia
| | - Marjetka Podobnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia.
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4
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Popoff MR. Overview of Bacterial Protein Toxins from Pathogenic Bacteria: Mode of Action and Insights into Evolution. Toxins (Basel) 2024; 16:182. [PMID: 38668607 PMCID: PMC11054074 DOI: 10.3390/toxins16040182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/29/2024] Open
Abstract
Bacterial protein toxins are secreted by certain bacteria and are responsible for mild to severe diseases in humans and animals. They are among the most potent molecules known, which are active at very low concentrations. Bacterial protein toxins exhibit a wide diversity based on size, structure, and mode of action. Upon recognition of a cell surface receptor (protein, glycoprotein, and glycolipid), they are active either at the cell surface (signal transduction, membrane damage by pore formation, or hydrolysis of membrane compound(s)) or intracellularly. Various bacterial protein toxins have the ability to enter cells, most often using an endocytosis mechanism, and to deliver the effector domain into the cytosol, where it interacts with an intracellular target(s). According to the nature of the intracellular target(s) and type of modification, various cellular effects are induced (cell death, homeostasis modification, cytoskeleton alteration, blockade of exocytosis, etc.). The various modes of action of bacterial protein toxins are illustrated with representative examples. Insights in toxin evolution are discussed.
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Affiliation(s)
- Michel R Popoff
- Unité des Toxines Bactériennes, Institut Pasteur, Université Paris Cité, CNRS UMR 2001 INSERM U1306, F-75015 Paris, France
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5
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Shannon BA, Hurst JR, Flannagan RS, Craig HC, Rishi A, Kasper KJ, Tuffs SW, Heinrichs DE, McCormick JK. Streptolysin S is required for Streptococcus pyogenes nasopharyngeal and skin infection in HLA-transgenic mice. PLoS Pathog 2024; 20:e1012072. [PMID: 38452154 PMCID: PMC10950238 DOI: 10.1371/journal.ppat.1012072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/19/2024] [Accepted: 02/25/2024] [Indexed: 03/09/2024] Open
Abstract
Streptococcus pyogenes is a human-specific pathogen that commonly colonizes the upper respiratory tract and skin, causing a wide variety of diseases ranging from pharyngitis to necrotizing fasciitis and toxic shock syndrome. S. pyogenes has a repertoire of secreted virulence factors that promote infection and evasion of the host immune system including the cytolysins streptolysin O (SLO) and streptolysin S (SLS). S. pyogenes does not naturally infect the upper respiratory tract of mice although mice transgenic for MHC class II human leukocyte antigens (HLA) become highly susceptible. Here we used HLA-transgenic mice to assess the role of both SLO and SLS during both nasopharyngeal and skin infection. Using S. pyogenes MGAS8232 as a model strain, we found that an SLS-deficient strain exhibited a 100-fold reduction in bacterial recovery from the nasopharynx and a 10-fold reduction in bacterial burden in the skin, whereas an SLO-deficient strain did not exhibit any infection defects in these models. Furthermore, depletion of neutrophils significantly restored the bacterial burden of the SLS-deficient bacteria in skin, but not in the nasopharynx. In mice nasally infected with the wildtype S. pyogenes, there was a marked change in localization of the tight junction protein ZO-1 at the site of infection, demonstrating damage to the nasal epithelia that was absent in mice infected with the SLS-deficient strain. Overall, we conclude that SLS is required for the establishment of nasopharyngeal infection and skin infection in HLA-transgenic mice by S. pyogenes MGAS8232 and provide evidence that SLS contributes to nasopharyngeal infection through the localized destruction of nasal epithelia.
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Affiliation(s)
- Blake A. Shannon
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Jacklyn R. Hurst
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Ronald S. Flannagan
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Heather C. Craig
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Aanchal Rishi
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Katherine J. Kasper
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Stephen W. Tuffs
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - David E. Heinrichs
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - John K. McCormick
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
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6
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Xu S, Smothers JC, Rye D, Endapally S, Chen H, Li S, Liang G, Kinnebrew M, Rohatgi R, Posner BA, Radhakrishnan A. A cholesterol-binding bacterial toxin provides a strategy for identifying a specific Scap inhibitor that blocks lipid synthesis in animal cells. Proc Natl Acad Sci U S A 2024; 121:e2318024121. [PMID: 38330014 PMCID: PMC10873635 DOI: 10.1073/pnas.2318024121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/15/2023] [Indexed: 02/10/2024] Open
Abstract
Lipid synthesis is regulated by the actions of Scap, a polytopic membrane protein that binds cholesterol in membranes of the endoplasmic reticulum (ER). When ER cholesterol levels are low, Scap activates SREBPs, transcription factors that upregulate genes for synthesis of cholesterol, fatty acids, and triglycerides. When ER cholesterol levels rise, the sterol binds to Scap, triggering conformational changes that prevent activation of SREBPs and halting synthesis of lipids. To achieve a molecular understanding of how cholesterol regulates the Scap/SREBP machine and to identify therapeutics for dysregulated lipid metabolism, cholesterol-mimetic compounds that specifically bind and inhibit Scap are needed. To accomplish this goal, we focused on Anthrolysin O (ALO), a pore-forming bacterial toxin that binds cholesterol with a specificity and sensitivity that is uncannily similar to Scap. We reasoned that a small molecule that would bind and inhibit ALO might also inhibit Scap. High-throughput screening of a ~300,000-compound library for ALO-binding unearthed one molecule, termed UT-59, which binds to Scap's cholesterol-binding site. Upon binding, UT-59 triggers the same conformation changes in Scap as those induced by cholesterol and blocks activation of SREBPs and lipogenesis in cultured cells. UT-59 also inhibits SREBP activation in the mouse liver. Unlike five previously reported inhibitors of SREBP activation, UT-59 is the only one that acts specifically by binding to Scap's cholesterol-binding site. Our approach to identify specific Scap inhibitors such as UT-59 holds great promise in developing therapeutic leads for human diseases stemming from elevated SREBP activation, such as fatty liver and certain cancers.
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Affiliation(s)
- Shimeng Xu
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Jared C. Smothers
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Daphne Rye
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Shreya Endapally
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Hong Chen
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Shili Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Guosheng Liang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Maia Kinnebrew
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
- Department of Medicine, Stanford University School of Medicine, Stanford, CA94305
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
- Department of Medicine, Stanford University School of Medicine, Stanford, CA94305
| | - Bruce A. Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Arun Radhakrishnan
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX75390
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7
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Koh DHZ, Naito T, Na M, Yeap YJ, Rozario P, Zhong FL, Lim KL, Saheki Y. Visualization of accessible cholesterol using a GRAM domain-based biosensor. Nat Commun 2023; 14:6773. [PMID: 37880244 PMCID: PMC10600248 DOI: 10.1038/s41467-023-42498-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 10/12/2023] [Indexed: 10/27/2023] Open
Abstract
Cholesterol is important for membrane integrity and cell signaling, and dysregulation of the distribution of cellular cholesterol is associated with numerous diseases, including neurodegenerative disorders. While regulated transport of a specific pool of cholesterol, known as "accessible cholesterol", contributes to the maintenance of cellular cholesterol distribution and homeostasis, tools to monitor accessible cholesterol in live cells remain limited. Here, we engineer a highly sensitive accessible cholesterol biosensor by taking advantage of the cholesterol-sensing element (the GRAM domain) of an evolutionarily conserved lipid transfer protein, GRAMD1b. Using this cholesterol biosensor, which we call GRAM-W, we successfully visualize in real time the distribution of accessible cholesterol in many different cell types, including human keratinocytes and iPSC-derived neurons, and show differential dependencies on cholesterol biosynthesis and uptake for maintaining levels of accessible cholesterol. Furthermore, we combine GRAM-W with a dimerization-dependent fluorescent protein (ddFP) and establish a strategy for the ultrasensitive detection of accessible plasma membrane cholesterol. These tools will allow us to obtain important insights into the molecular mechanisms by which the distribution of cellular cholesterol is regulated.
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Affiliation(s)
- Dylan Hong Zheng Koh
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Tomoki Naito
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Minyoung Na
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Yee Jie Yeap
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Pritisha Rozario
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Franklin L Zhong
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
- Skin Research Institute of Singapore (SRIS), Singapore, 308232, Singapore
| | - Kah-Leong Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
- National Neuroscience Institute, Singapore, 308433, Singapore
| | - Yasunori Saheki
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore.
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, 860-0811, Japan.
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8
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Petrišič N, Adamek M, Kežar A, Hočevar SB, Žagar E, Anderluh G, Podobnik M. Structural basis for the unique molecular properties of broad-range phospholipase C from Listeria monocytogenes. Nat Commun 2023; 14:6474. [PMID: 37838694 PMCID: PMC10576769 DOI: 10.1038/s41467-023-42134-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 09/28/2023] [Indexed: 10/16/2023] Open
Abstract
Listeriosis is one of the most serious foodborne diseases caused by the intracellular bacterium Listeria monocytogenes. Its two major virulence factors, broad-range phospholipase C (LmPC-PLC) and the pore-forming toxin listeriolysin O (LLO), enable the bacterium to spread in the host by destroying cell membranes. Here, we determine the crystal structure of LmPC-PLC and complement it with the functional analysis of this enzyme. This reveals that LmPC-PLC has evolved several structural features to regulate its activity, including the invariant position of the N-terminal tryptophan (W1), the structurally plastic active site, Zn2+-dependent activity, and the tendency to form oligomers with impaired enzymatic activity. We demonstrate that the enzymatic activity of LmPC-PLC can be specifically inhibited by its propeptide added in trans. Furthermore, we show that the phospholipase activity of LmPC-PLC facilitates the pore-forming activity of LLO and affects the morphology of LLO oligomerization on lipid membranes, revealing the multifaceted synergy of the two virulence factors.
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Affiliation(s)
- Nejc Petrišič
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
- PhD Program 'Biosciences', Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Maksimiljan Adamek
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Andreja Kežar
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Samo B Hočevar
- Department of Analytical Chemistry, National Institute of Chemistry, Ljubljana, Slovenia
| | - Ema Žagar
- Department of Polymer Chemistry and Technology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Marjetka Podobnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia.
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9
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Whiting R, Stanton S, Kucheriava M, Smith AR, Pitts M, Robertson D, Kammer J, Li Z, Fologea D. Hypo-Osmotic Stress and Pore-Forming Toxins Adjust the Lipid Order in Sheep Red Blood Cell Membranes. MEMBRANES 2023; 13:620. [PMID: 37504986 PMCID: PMC10385129 DOI: 10.3390/membranes13070620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/07/2023] [Accepted: 06/22/2023] [Indexed: 07/29/2023]
Abstract
Lipid ordering in cell membranes has been increasingly recognized as an important factor in establishing and regulating a large variety of biological functions. Multiple investigations into lipid organization focused on assessing ordering from temperature-induced phase transitions, which are often well outside the physiological range. However, particular stresses elicited by environmental factors, such as hypo-osmotic stress or protein insertion into membranes, with respect to changes in lipid status and ordering at constant temperature are insufficiently described. To fill these gaps in our knowledge, we exploited the well-established ability of environmentally sensitive membrane probes to detect intramembrane changes at the molecular level. Our steady state fluorescence spectroscopy experiments focused on assessing changes in optical responses of Laurdan and diphenylhexatriene upon exposure of red blood cells to hypo-osmotic stress and pore-forming toxins at room temperature. We verified our utilized experimental systems by a direct comparison of the results with prior reports on artificial membranes and cholesterol-depleted membranes undergoing temperature changes. The significant changes observed in the lipid order after exposure to hypo-osmotic stress or pore-forming toxins resembled phase transitions of lipids in membranes, which we explained by considering the short-range interactions between membrane components and the hydrophobic mismatch between membrane thickness and inserted proteins. Our results suggest that measurements of optical responses from the membrane probes constitute an appropriate method for assessing the status of lipids and phase transitions in target membranes exposed to mechanical stresses or upon the insertion of transmembrane proteins.
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Affiliation(s)
- Rose Whiting
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
| | - Sevio Stanton
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | | | - Aviana R Smith
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Matt Pitts
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
| | - Daniel Robertson
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Jacob Kammer
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Department of Family Medicine, Idaho College of Osteopathic Medicine, Meridian, ID 83642, USA
| | - Zhiyu Li
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Daniel Fologea
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
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10
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Heisler DB, Johnson KA, Ma DH, Ohlson MB, Zhang L, Tran M, Corley CD, Abrams ME, McDonald JG, Schoggins JW, Alto NM, Radhakrishnan A. A concerted mechanism involving ACAT and SREBPs by which oxysterols deplete accessible cholesterol to restrict microbial infection. eLife 2023; 12:e83534. [PMID: 36695568 PMCID: PMC9925056 DOI: 10.7554/elife.83534] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 01/25/2023] [Indexed: 01/26/2023] Open
Abstract
Most of the cholesterol in the plasma membranes (PMs) of animal cells is sequestered through interactions with phospholipids and transmembrane domains of proteins. However, as cholesterol concentration rises above the PM's sequestration capacity, a new pool of cholesterol, called accessible cholesterol, emerges. The transport of accessible cholesterol between the PM and the endoplasmic reticulum (ER) is critical to maintain cholesterol homeostasis. This pathway has also been implicated in the suppression of both bacterial and viral pathogens by immunomodulatory oxysterols. Here, we describe a mechanism of depletion of accessible cholesterol from PMs by the oxysterol 25-hydroxycholesterol (25HC). We show that 25HC-mediated activation of acyl coenzyme A: cholesterol acyltransferase (ACAT) in the ER creates an imbalance in the equilibrium distribution of accessible cholesterol between the ER and PM. This imbalance triggers the rapid internalization of accessible cholesterol from the PM, and this depletion is sustained for long periods of time through 25HC-mediated suppression of SREBPs and continued activation of ACAT. In support of a physiological role for this mechanism, 25HC failed to suppress Zika virus and human coronavirus infection in ACAT-deficient cells, and Listeria monocytogenes infection in ACAT-deficient cells and mice. We propose that selective depletion of accessible PM cholesterol triggered by ACAT activation and sustained through SREBP suppression underpins the immunological activities of 25HC and a functionally related class of oxysterols.
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Affiliation(s)
- David B Heisler
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Kristen A Johnson
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Duo H Ma
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Maikke B Ohlson
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Lishu Zhang
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Michelle Tran
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Chase D Corley
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Michael E Abrams
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Jeffrey G McDonald
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
| | - John W Schoggins
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Neal M Alto
- Department of Microbiology, The University of Texas Southwestern Medical CenterDallasUnited States
| | - Arun Radhakrishnan
- Department of Molecular Genetics, The University of Texas Southwestern Medical CenterDallasUnited States
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11
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Senior MJT, Monico C, Weatherill EE, Gilbert RJ, Heuck AP, Wallace MI. Single-molecule tracking of perfringolysin O assembly and membrane insertion uncoupling. FEBS J 2023; 290:428-441. [PMID: 35989549 PMCID: PMC10086847 DOI: 10.1111/febs.16596] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/22/2022] [Accepted: 08/15/2022] [Indexed: 02/05/2023]
Abstract
We exploit single-molecule tracking and optical single channel recording in droplet interface bilayers to resolve the assembly pathway and pore formation of the archetypical cholesterol-dependent cytolysin nanopore, Perfringolysin O. We follow the stoichiometry and diffusion of Perfringolysin O complexes during assembly with 60 ms temporal resolution and 20 nm spatial precision. Our results suggest individual nascent complexes can insert into the lipid membrane where they continue active assembly. Overall, these data support a model of stepwise irreversible assembly dominated by monomer addition, but with infrequent assembly from larger partial complexes.
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Affiliation(s)
- Michael J T Senior
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, UK
| | - Carina Monico
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, UK.,Department of Chemistry, King's College London, UK
| | - Eve E Weatherill
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, UK.,Department of Chemistry, King's College London, UK
| | - Robert J Gilbert
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, UK
| | - Alejandro P Heuck
- Departments of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, USA
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12
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Johnstone BA, Joseph R, Christie MP, Morton CJ, McGuiness C, Walsh JC, Böcking T, Tweten RK, Parker MW. Cholesterol-dependent cytolysins: The outstanding questions. IUBMB Life 2022; 74:1169-1179. [PMID: 35836358 PMCID: PMC9712165 DOI: 10.1002/iub.2661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 06/23/2022] [Indexed: 11/06/2022]
Abstract
The cholesterol-dependent cytolysins (CDCs) are a major family of bacterial pore-forming proteins secreted as virulence factors by Gram-positive bacterial species. CDCs are produced as soluble, monomeric proteins that bind specifically to cholesterol-rich membranes, where they oligomerize into ring-shaped pores of more than 30 monomers. Understanding the details of the steps the toxin undergoes in converting from monomer to a membrane-spanning pore is a continuing challenge. In this review we summarize what we know about CDCs and highlight the remaining outstanding questions that require answers to obtain a complete picture of how these toxins kill cells.
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Affiliation(s)
- Bronte A Johnstone
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Riya Joseph
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Michelle P Christie
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Craig J Morton
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Conall McGuiness
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - James C Walsh
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Till Böcking
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Rodney K Tweten
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Michael W Parker
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- Australian Cancer Research Foundation Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
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13
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Structure of the Streptococcus pyogenes NADase translocation domain and its essential role in toxin binding to oropharyngeal keratinocytes. J Bacteriol 2021; 204:e0036621. [PMID: 34694903 DOI: 10.1128/jb.00366-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emergence and continued dominance of a Streptococcus pyogenes (group A Streptococcus, GAS) M1T1 clonal group is temporally correlated with acquisition of genomic sequences that confer high level expression of co-toxins streptolysin O (SLO) and NAD+-glycohydrolase (NADase). Experimental infection models have provided evidence that both toxins are important contributors to GAS virulence. SLO is a cholesterol-dependent pore-forming toxin capable of lysing virtually all types of mammalian cells. NADase, which is composed of an N-terminal translocation domain and C-terminal glycohydrolase domain, acts as an intracellular toxin that depletes host cell energy stores. NADase is dependent on SLO for internalization into epithelial cells, but its mechanism of interaction with the cell surface and details of its translocation mechanism remain unclear. In this study we found that NADase can bind oropharyngeal epithelial cells independently of SLO. This interaction is mediated by both domains of the toxin. We determined by NMR the structure of the translocation domain to be a β-sandwich with a disordered N-terminal region. The folded region of the domain has structural homology to carbohydrate binding modules. We show that excess NADase inhibits SLO-mediated hemolysis and binding to epithelial cells in vitro, suggesting NADase and SLO have shared surface receptors. This effect is abrogated by disruption of a putative carbohydrate binding site on the NADase translocation domain. Our data are consistent with a model whereby interactions of the NADase glycohydrolase domain and translocation domain with SLO and the cell surface increase avidity of NADase binding and facilitate toxin-toxin and toxin-cell surface interactions. Importance NADase and streptolysin O (SLO) are secreted toxins important for pathogenesis of group A Streptococcus, the agent of strep throat and severe invasive infections. The two toxins interact in solution and mutually enhance cytotoxic activity. We now find that NADase is capable of binding to the surface of human cells independently of SLO. Structural analysis of the previously uncharacterized translocation domain of NADase suggests that it contains a carbohydrate binding module. The NADase translocation domain and SLO appear to recognize similar glycan structures on the cell surface, which may be one mechanism through which NADase enhances SLO pore-forming activity during infection. Our findings provide new insight into the NADase toxin and its functional interactions with SLO during streptococcal infection.
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14
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Tabata A, Nagamune H. Diversity of β-hemolysins produced by the human opportunistic streptococci. Microbiol Immunol 2021; 65:512-529. [PMID: 34591320 DOI: 10.1111/1348-0421.12936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/28/2022]
Abstract
The genus Streptococcus infects a broad range of hosts, including humans. Some species, such as S. pyogenes, S. agalactiae, S. pneumoniae, and S. mutans, are recognized as the major human pathogens, and their pathogenicity toward humans has been investigated. However, many of other streptococcal species have been recognized as opportunistic pathogens in humans, and their clinical importance has been underestimated. In our previous study, the Anginosus group streptococci (AGS) and Mitis group streptococci (MGS) showed clear β-hemolysis on blood agar, and the factors responsible for the hemolysis were homologs of two types of β-hemolysins, cholesterol-dependent cytolysin (CDC) and streptolysin S (SLS). In contrast to the regular β-hemolysins produced by streptococci (typical CDCs and SLSs), genetically, structurally, and functionally atypical β-hemolysins have been observed in AGS and MGS. These atypical β-hemolysins are thought to affect and contribute to the pathogenic potential of opportunistic streptococci mainly inhabiting the human oral cavity. In this review, we introduce the diverse characteristics of β-hemolysin produced by opportunistic streptococci, focusing on the species/strains belonging to AGS and MGS, and discuss their pathogenic potential.
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Affiliation(s)
- Atsushi Tabata
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Hideaki Nagamune
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan
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15
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Draberova L, Tumova M, Draber P. Molecular Mechanisms of Mast Cell Activation by Cholesterol-Dependent Cytolysins. Front Immunol 2021; 12:670205. [PMID: 34248949 PMCID: PMC8260682 DOI: 10.3389/fimmu.2021.670205] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 06/08/2021] [Indexed: 12/23/2022] Open
Abstract
Mast cells are potent immune sensors of the tissue microenvironment. Within seconds of activation, they release various preformed biologically active products and initiate the process of de novo synthesis of cytokines, chemokines, and other inflammatory mediators. This process is regulated at multiple levels. Besides the extensively studied IgE and IgG receptors, toll-like receptors, MRGPR, and other protein receptor signaling pathways, there is a critical activation pathway based on cholesterol-dependent, pore-forming cytolytic exotoxins produced by Gram-positive bacterial pathogens. This pathway is initiated by binding the exotoxins to the cholesterol-rich membrane, followed by their dimerization, multimerization, pre-pore formation, and pore formation. At low sublytic concentrations, the exotoxins induce mast cell activation, including degranulation, intracellular calcium concentration changes, and transcriptional activation, resulting in production of cytokines and other inflammatory mediators. Higher toxin concentrations lead to cell death. Similar activation events are observed when mast cells are exposed to sublytic concentrations of saponins or some other compounds interfering with the membrane integrity. We review the molecular mechanisms of mast cell activation by pore-forming bacterial exotoxins, and other compounds inducing cholesterol-dependent plasma membrane perturbations. We discuss the importance of these signaling pathways in innate and acquired immunity.
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Affiliation(s)
- Lubica Draberova
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Magda Tumova
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Petr Draber
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
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16
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Liposomes Prevent In Vitro Hemolysis Induced by Streptolysin O and Lysenin. MEMBRANES 2021; 11:membranes11050364. [PMID: 34069894 PMCID: PMC8157566 DOI: 10.3390/membranes11050364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/08/2021] [Accepted: 05/12/2021] [Indexed: 12/12/2022]
Abstract
The need for alternatives to antibiotics in the fight against infectious diseases has inspired scientists to focus on antivirulence factors instead of the microorganisms themselves. In this respect, prior work indicates that tiny, enclosed bilayer lipid membranes (liposomes) have the potential to compete with cellular targets for toxin binding, hence preventing their biological attack and aiding with their clearance. The effectiveness of liposomes as decoy targets depends on their availability in the host and how rapidly they are cleared from the circulation. Although liposome PEGylation may improve their circulation time, little is known about how such a modification influences their interactions with antivirulence factors. To fill this gap in knowledge, we investigated regular and long-circulating liposomes for their ability to prevent in vitro red blood cell hemolysis induced by two potent lytic toxins, lysenin and streptolysin O. Our explorations indicate that both regular and long-circulating liposomes are capable of similarly preventing lysis induced by streptolysin O. In contrast, PEGylation reduced the effectiveness against lysenin-induced hemolysis and altered binding dynamics. These results suggest that toxin removal by long-circulating liposomes is feasible, yet dependent on the particular virulence factor under scrutiny.
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17
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The Streptococcus pyogenes signaling peptide SpoV regulates streptolysin O and enhances survival in murine blood. J Bacteriol 2021; 203:JB.00586-20. [PMID: 33722844 PMCID: PMC8117530 DOI: 10.1128/jb.00586-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pyogenes (Group A Streptococcus, GAS) is a human pathogen that causes a wide range of diseases. For successful colonization within a variety of host niches, GAS must sense and respond to environmental changes. Intercellular communication mediated by peptides is one way GAS coordinates gene expression in response to diverse environmental stressors, which enhances bacterial survival and contributes to virulence. Using peptidomics we identified SpoV (Streptococcal peptide controlling virulence) in culture supernatant fluids. SpoV is a secreted peptide encoded near the gene encoding the extracellular cholesterol-dependent cytolysin streptolysin O (slo) The addition of synthetic SpoV peptide derivatives, but not control peptides, increased slo transcript abundance in an M49 isolate but not in an M3 isolate. Deletion of spoV decreased slo transcript abundance, extracellular SLO protein levels, and SLO-specific hemolytic activity. Complementation of the spoV mutant increased slo transcript abundance. Lastly, a spoV mutant was deficient in the ability to survive in murine blood compared to the parental strain. Moreover, pre-incubation of the spoV mutant with synthetic SpoV peptide derivatives increased GAS survival. Our findings show that slo expression is regulated, in part, by the GAS-specific signaling peptide SpoV.IMPORTANCEGAS secretes signaling peptides that can alter gene expression and impact virulence. We used peptidomics to identify a signaling peptide designated SpoV. Further, we showed that SpoV altered the expression of the cholesterol-dependent cytolysin SLO. Peptide signaling plays an important regulatory role during disease progression among several bacterial pathogens, including GAS. The therapeutic potential of manipulating peptide-controlled regulatory networks is an attractive option for the development of novel therapeutic strategies that disrupt virulence gene expression.
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18
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Banerji R, Karkee A, Kanojiya P, Saroj SD. Pore-forming toxins of foodborne pathogens. Compr Rev Food Sci Food Saf 2021; 20:2265-2285. [PMID: 33773026 DOI: 10.1111/1541-4337.12737] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 02/01/2021] [Accepted: 02/08/2021] [Indexed: 01/04/2023]
Abstract
Pore-forming toxins (PFTs) are water-soluble molecules that have been identified as the most crucial virulence factors during bacterial pathogenesis. PFTs disrupt the host cell membrane to internalize or to deliver other bacterial or virulence factors for establishing infections. Disruption of the host cell membrane by PFTs can lead to uncontrollable exchanges between the extracellular and the intracellular matrix, thereby disturbing the cellular homeostasis. Recent studies have provided insights into the molecular mechanism of PFTs during pathogenesis. Evidence also suggests the activation of several signal transduction pathways in the host cell on recognition of PFTs. Additionally, numerous distinctive host defense mechanisms as well as membrane repair mechanisms have been reported; however, studies reveal that PFTs aid in host immune evasion of the bacteria through numerous pathways. PFTs have been primarily associated with foodborne pathogens. Infection and death from diseases by consuming contaminated food are a constant threat to public health worldwide, affecting socioeconomic development. Moreover, the emergence of new foodborne pathogens has led to the rise of bacterial antimicrobial resistance affecting the population. Hence, this review focuses on the role of PFTs secreted by foodborne pathogens. The review highlights the molecular mechanism of foodborne bacterial PFTs, assisting bacterial survival from the host immune responses and understanding the downstream mechanism in the activation of various signaling pathways in the host upon PFT recognition. PFT research is a remarkable and an important field for exploring novel and broad applications of antimicrobial compounds as therapeutics.
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Affiliation(s)
- Rajashri Banerji
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, India
| | - Astha Karkee
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, India
| | - Poonam Kanojiya
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, India
| | - Sunil D Saroj
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune, India
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19
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The molecular mechanisms of listeriolysin O-induced lipid membrane damage. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183604. [PMID: 33722646 DOI: 10.1016/j.bbamem.2021.183604] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/05/2021] [Accepted: 03/05/2021] [Indexed: 12/22/2022]
Abstract
Listeria monocytogenes is an intracellular food-borne pathogen that causes listeriosis, a severe and potentially life-threatening disease. Listeria uses a number of virulence factors to proliferate and spread to various cells and tissues. In this process, three bacterial virulence factors, the pore-forming protein listeriolysin O and phospholipases PlcA and PlcB, play a crucial role. Listeriolysin O belongs to a family of cholesterol-dependent cytolysins that are mostly expressed by gram-positive bacteria. Its unique structural features in an otherwise conserved three-dimensional fold, such as the acidic triad and proline-glutamate-serine-threonine-like sequence, enable the regulation of its intracellular activity as well as distinct extracellular functions. The stability of listeriolysin O is pH- and temperature-dependent, and this provides another layer of control of its activity in cells. Moreover, many recent studies have demonstrated a unique mechanism of pore formation by listeriolysin O, i.e., the formation of arc-shaped oligomers that can subsequently fuse to form membrane defects of various shapes and sizes. During listerial invasion of host cells, these membrane defects can disrupt phagosome membranes, allowing bacteria to escape into the cytosol and rapidly multiply. The activity of listeriolysin O is profoundly dependent on the amount and accessibility of cholesterol in the lipid membrane, which can be modulated by the phospholipase PlcB. All these prominent features of listeriolysin O play a role during different stages of the L. monocytogenes life cycle by promoting the proliferation of the pathogen while mitigating excessive damage to its replicative niche in the cytosol of the host cell.
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20
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Wang G, Gao Y, Xu X, Zhang P, Wang J, Li G, Lv Q, Niu X, Liu H. Mode of action and structural modelling of the interaction of formononetin with suilysin. J Appl Microbiol 2021; 131:2010-2018. [PMID: 33639036 DOI: 10.1111/jam.15051] [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: 10/28/2020] [Revised: 02/02/2021] [Accepted: 02/17/2021] [Indexed: 11/28/2022]
Abstract
AIMS Suilysin is a critical pore-forming virulence factor of Streptococcus suis that has been demonstrated to substantially contribute to its pathogenicity. We have demonstrated that formononetin alleviates S. suis infection both in vivo and in vitro by targeting suilysin. However, the molecular mechanism of the effect is unclear. Our aim was to determine the molecular mechanism of the effect of formononetin on suilysin. METHODS AND RESULTS The mechanism of interaction between formononetin and suilysin was investigated by molecular modelling. The results indicated that formononetin was bound at the junction of domain two and domain four of suilysin. The binding free energy values indicated that the A415, Y412, E414, N413, T61, T62 and G416 residues are critical for this binding, this observation was confirmed by the changes in the flexibility of these residues and the distances between these residues and formononetin. The inhibitory effect of formononetin on the pore-forming activity of suilysin, binding constant and binding free energy were significantly decreased by site-specific mutagenesis of Y412 and N413. Finally, we analysed the spatial configuration of suilysin before and after formononetin binding, the results indicated that the binding changed the conformation of suilysin, especially the angle between domain two and domain four, resulting in the disruption of cholesterol binding to suilysin and in the loss of pore-forming activity. CONCLUSIONS Formononetin is located at the junction of domain two and domain four of suilysin, and Y412 and N413 play critical roles in the binding. Formononetin binding changes the angle between domain two and domain four of suilysin, resulting in the loss of the pore-inducing activity of suilysin. SIGNIFICANCE AND IMPACT OF THE STUDY This work will promote the application of formononetin to combat S. suis infections and may contribute to the development of new inhibitors or modification of existing inhibitors.
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Affiliation(s)
- G Wang
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, PR China.,College of Food Engineering, Jilin Engineering Normal University, Changchun, China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - Y Gao
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, PR China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - X Xu
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, PR China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - P Zhang
- College of Food Engineering, Jilin Engineering Normal University, Changchun, China
| | - J Wang
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, PR China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - G Li
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Q Lv
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, PR China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - X Niu
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - H Liu
- Department of Respiratory Medicine, the First Hospital of Jilin University, Changchun, PR China
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21
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Li Y, Li Y, Mengist HM, Shi C, Zhang C, Wang B, Li T, Huang Y, Xu Y, Jin T. Structural Basis of the Pore-Forming Toxin/Membrane Interaction. Toxins (Basel) 2021; 13:toxins13020128. [PMID: 33572271 PMCID: PMC7914777 DOI: 10.3390/toxins13020128] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/13/2021] [Accepted: 02/02/2021] [Indexed: 12/14/2022] Open
Abstract
With the rapid growth of antibiotic-resistant bacteria, it is urgent to develop alternative therapeutic strategies. Pore-forming toxins (PFTs) belong to the largest family of virulence factors of many pathogenic bacteria and constitute the most characterized classes of pore-forming proteins (PFPs). Recent studies revealed the structural basis of several PFTs, both as soluble monomers, and transmembrane oligomers. Upon interacting with host cells, the soluble monomer of bacterial PFTs assembles into transmembrane oligomeric complexes that insert into membranes and affect target cell-membrane permeability, leading to diverse cellular responses and outcomes. Herein we have reviewed the structural basis of pore formation and interaction of PFTs with the host cell membrane, which could add valuable contributions in comprehensive understanding of PFTs and searching for novel therapeutic strategies targeting PFTs and interaction with host receptors in the fight of bacterial antibiotic-resistance.
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Affiliation(s)
- Yajuan Li
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Yuelong Li
- Hefei National Laboratory for Physical Sciences at Microscale, Laboratory of Structural Immunology, CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Life Sciences and Medicine, School of Basic Medical Sciences, University of Science and Technology of China, Hefei 230027, China; (Y.L.); (H.M.M.); (C.Z.)
| | - Hylemariam Mihiretie Mengist
- Hefei National Laboratory for Physical Sciences at Microscale, Laboratory of Structural Immunology, CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Life Sciences and Medicine, School of Basic Medical Sciences, University of Science and Technology of China, Hefei 230027, China; (Y.L.); (H.M.M.); (C.Z.)
| | - Cuixiao Shi
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Caiying Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, Laboratory of Structural Immunology, CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Life Sciences and Medicine, School of Basic Medical Sciences, University of Science and Technology of China, Hefei 230027, China; (Y.L.); (H.M.M.); (C.Z.)
| | - Bo Wang
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Tingting Li
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Ying Huang
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Yuanhong Xu
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
- Correspondence: (Y.X.); (T.J.); Tel.: +86-13505694447 (Y.X.); +86-17605607323 (T.J.)
| | - Tengchuan Jin
- Hefei National Laboratory for Physical Sciences at Microscale, Laboratory of Structural Immunology, CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Life Sciences and Medicine, School of Basic Medical Sciences, University of Science and Technology of China, Hefei 230027, China; (Y.L.); (H.M.M.); (C.Z.)
- Correspondence: (Y.X.); (T.J.); Tel.: +86-13505694447 (Y.X.); +86-17605607323 (T.J.)
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22
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Molecular Dynamics Study of Lipid and Cholesterol Reorganization Due to Membrane Binding and Pore Formation by Listeriolysin O. J Membr Biol 2020; 253:535-550. [DOI: 10.1007/s00232-020-00148-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 10/10/2020] [Indexed: 12/20/2022]
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23
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Lencer WI. Everything Illuminated-Clostridium perfringens β-toxin. Cell Host Microbe 2020; 28:5-6. [PMID: 32645353 DOI: 10.1016/j.chom.2020.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In this issue of Cell Host & Microbe, Bruggisser et al. show that Clostridium perfringens β-toxin (CPB) binds platelet endothelial cell adhesion molecule-1 (PECAM-1) (also known as CD31) to induce membrane pores. The discovery explains the cell type specificity for CPB and, in large part, the basic pathophysiology of disease.
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Affiliation(s)
- Wayne I Lencer
- Boston Children's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA; Harvard Digestive Disease Center, Boston, MA 02115, USA.
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24
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Herrera AL, Van Hove C, Hanson M, Dale JB, Tweten RK, Huber VC, Diel D, Chaussee MS. Immunotherapy targeting the Streptococcus pyogenes M protein or streptolysin O to treat or prevent influenza A superinfection. PLoS One 2020; 15:e0235139. [PMID: 32574205 PMCID: PMC7310742 DOI: 10.1371/journal.pone.0235139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/09/2020] [Indexed: 12/12/2022] Open
Abstract
Viral infections complicated by a bacterial infection are typically referred to as coinfections or superinfections. Streptococcus pyogenes, the group A streptococcus (GAS), is not the most common bacteria associated with influenza A virus (IAV) superinfections but did cause significant mortality during the 2009 influenza pandemic even though all isolates are susceptible to penicillin. One approach to improve the outcome of these infections is to use passive immunization targeting GAS. To test this idea, we assessed the efficacy of passive immunotherapy using antisera against either the streptococcal M protein or streptolysin O (SLO) in a murine model of IAV-GAS superinfection. Prophylactic treatment of mice with antiserum to either SLO or the M protein decreased morbidity compared to mice treated with non-immune sera; however, neither significantly decreased mortality. Therapeutic use of antisera to SLO decreased morbidity compared to mice treated with non-immune sera but neither antisera significantly reduced mortality. Overall, the results suggest that further development of antibodies targeting the M protein or SLO may be a useful adjunct in the treatment of invasive GAS diseases, including IAV-GAS superinfections, which may be particularly important during influenza pandemics.
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Affiliation(s)
- Andrea L. Herrera
- Division of Basic Biomedical Sciences, The Sanford School of Medicine of the University of South Dakota, Vermillion, SD, United States of America
| | - Christopher Van Hove
- Division of Basic Biomedical Sciences, The Sanford School of Medicine of the University of South Dakota, Vermillion, SD, United States of America
| | - Mary Hanson
- Division of Basic Biomedical Sciences, The Sanford School of Medicine of the University of South Dakota, Vermillion, SD, United States of America
| | - James B. Dale
- Department of Medicine, Division of Infectious Diseases, University of Tennessee Health Science Center, Memphis, TN, United States of America
| | - Rodney K. Tweten
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
| | - Victor C. Huber
- Division of Basic Biomedical Sciences, The Sanford School of Medicine of the University of South Dakota, Vermillion, SD, United States of America
| | - Diego Diel
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD, United States of America
| | - Michael S. Chaussee
- Division of Basic Biomedical Sciences, The Sanford School of Medicine of the University of South Dakota, Vermillion, SD, United States of America
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25
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Identification of a Cytopathogenic Toxin from Sneathia amnii. J Bacteriol 2020; 202:JB.00162-20. [PMID: 32291280 DOI: 10.1128/jb.00162-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 04/04/2020] [Indexed: 12/22/2022] Open
Abstract
Sneathia amnii is a poorly characterized emerging pathogen that has been implicated in amnionitis and urethritis. We found that S. amnii damages fetal membranes, and we identified and purified a cytotoxic exotoxin that lyses human red blood cells and damages cells from fetal membranes. The gene appears to be cotranscribed with a second gene that encodes a protein with identity to two-partner system transporters, suggesting that it is the "A," or secreted component of a type Vb system. The toxin is 1,881 amino acids with a molecular weight of approximately 200 kDa. It binds to red blood cell membranes and forms pores with a diameter of 2.0 to 3.0 nm, resulting in osmolysis. Because it appears to be the "A" or passenger component of a two-partner system, we propose to name this novel cytotoxin/hemolysin CptA for cytopathogenic toxin component A.IMPORTANCE Sneathia amnii is a very poorly characterized emerging pathogen that can affect pregnancy outcome and cause urethritis and other infections. To date, nothing is known about its virulence factors or pathogenesis. We have identified and isolated a cytotoxin, named CptA for cytopathogenic toxin, component A, that is produced by S. amnii CptA is capable of permeabilizing chorionic trophoblasts and lysing human red blood cells and, thus, may play a role in virulence. Except for small domains conserved among two-partner secretion system passenger proteins, the cytotoxin exhibits little amino acid sequence homology to known toxins. In this study, we demonstrate the pore-forming activity of this novel toxin.
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26
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Zhou QD, Chi X, Lee MS, Hsieh WY, Mkrtchyan JJ, Feng AC, He C, York AG, Bui VL, Kronenberger EB, Ferrari A, Xiao X, Daly AE, Tarling EJ, Damoiseaux R, Scumpia PO, Smale ST, Williams KJ, Tontonoz P, Bensinger SJ. Interferon-mediated reprogramming of membrane cholesterol to evade bacterial toxins. Nat Immunol 2020; 21:746-755. [PMID: 32514064 PMCID: PMC7778040 DOI: 10.1038/s41590-020-0695-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/28/2020] [Indexed: 12/21/2022]
Abstract
Plasma membranes of animal cells are enriched for cholesterol. Cholesterol-dependent cytolysins (CDCs) are pore-forming toxins secreted by bacteria that target membrane cholesterol for their effector function. Phagocytes are essential for clearance of CDC-producing bacteria; however, the mechanisms by which these cells evade the deleterious effects of CDCs are largely unknown. Here, we report that interferon (IFN) signals convey resistance to CDC-induced pores on macrophages and neutrophils. We traced IFN-mediated resistance to CDCs to the rapid modulation of a specific pool of cholesterol in the plasma membrane of macrophages without changes to total cholesterol levels. Resistance to CDC-induced pore formation requires the production of the oxysterol 25-hydroxycholesterol (25HC), inhibition of cholesterol synthesis and redistribution of cholesterol to an esterified cholesterol pool. Accordingly, blocking the ability of IFN to reprogram cholesterol metabolism abrogates cellular protection and renders mice more susceptible to CDC-induced tissue damage. These studies illuminate targeted regulation of membrane cholesterol content as a host defense strategy.
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Affiliation(s)
- Quan D Zhou
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Surgical Oncology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, P.R. China
| | - Xun Chi
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Min Sub Lee
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Wei Yuan Hsieh
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jonathan J Mkrtchyan
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - An-Chieh Feng
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Cuiwen He
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Autumn G York
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
| | - Viet L Bui
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Eliza B Kronenberger
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Alessandra Ferrari
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Xu Xiao
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Allison E Daly
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Elizabeth J Tarling
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Robert Damoiseaux
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Philip O Scumpia
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Stephen T Smale
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Kevin J Williams
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Steven J Bensinger
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA. .,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
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27
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Omersa N, Aden S, Kisovec M, Podobnik M, Anderluh G. Design of Protein Logic Gate System Operating on Lipid Membranes. ACS Synth Biol 2020; 9:316-328. [PMID: 31995709 PMCID: PMC7308068 DOI: 10.1021/acssynbio.9b00340] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Indexed: 12/16/2022]
Abstract
Lipid membranes are becoming increasingly popular in synthetic biology due to their biophysical properties and crucial role in communication between different compartments. Several alluring protein-membrane sensors have already been developed, whereas protein logic gates designs on membrane-embedded proteins are very limited. Here we demonstrate the construction of a two-level protein-membrane logic gate with an OR-AND logic. The system consists of an engineered pH-dependent pore-forming protein listeriolysin O and its DARPin-based inhibitor, conjugated to a lipid vesicle membrane. The gate responds to low pH and removal of the inhibitor from the membrane either by switching to a reducing environment, protease cleavage, or any other signal depending on the conjugation chemistry used for inhibitor attachment to the membrane. This unique protein logic gate vesicle system advances generic sensing and actuator platforms used in synthetic biology and could be utilized in drug delivery.
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Affiliation(s)
- Neža Omersa
- Department
of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova ulica 19, 1001 Ljubljana, Slovenia
- Biomedicine
Doctoral Program, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Saša Aden
- Department
of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova ulica 19, 1001 Ljubljana, Slovenia
- Biomedicine
Doctoral Program, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Matic Kisovec
- Department
of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova ulica 19, 1001 Ljubljana, Slovenia
| | - Marjetka Podobnik
- Department
of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova ulica 19, 1001 Ljubljana, Slovenia
| | - Gregor Anderluh
- Department
of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova ulica 19, 1001 Ljubljana, Slovenia
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28
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Adams W, Bhowmick R, Bou Ghanem EN, Wade K, Shchepetov M, Weiser JN, McCormick BA, Tweten RK, Leong JM. Pneumolysin Induces 12-Lipoxygenase-Dependent Neutrophil Migration during Streptococcus pneumoniae Infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2020; 204:101-111. [PMID: 31776202 PMCID: PMC7195902 DOI: 10.4049/jimmunol.1800748] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/16/2019] [Indexed: 12/23/2022]
Abstract
Streptococcus pneumoniae is a major cause of pneumonia, wherein infection of respiratory mucosa drives a robust influx of neutrophils. We have previously shown that S. pneumoniae infection of the respiratory epithelium induces the production of the 12-lipoxygenase (12-LOX)-dependent lipid inflammatory mediator hepoxilin A3, which promotes recruitment of neutrophils into the airways, tissue damage, and lethal septicemia. Pneumolysin (PLY), a member of the cholesterol-dependent cytolysin (CDC) family, is a major S. pneumoniae virulence factor that generates ∼25-nm diameter pores in eukaryotic membranes and promotes acute inflammation, tissue damage, and bacteremia. We show that a PLY-deficient S. pneumoniae mutant was impaired in triggering human neutrophil transepithelial migration in vitro. Ectopic production of PLY endowed the nonpathogenic Bacillus subtilis with the ability to trigger neutrophil recruitment across human-cultured monolayers. Purified PLY, several other CDC family members, and the α-toxin of Clostridium septicum, which generates pores with cross-sectional areas nearly 300 times smaller than CDCs, reproduced this robust neutrophil transmigration. PLY non-pore-forming point mutants that are trapped at various stages of pore assembly did not recruit neutrophils. PLY triggered neutrophil recruitment in a 12-LOX-dependent manner in vitro. Instillation of wild-type PLY but not inactive derivatives into the lungs of mice induced robust 12-LOX-dependent neutrophil migration into the airways, although residual inflammation induced by PLY in 12-LOX-deficient mice indicates that 12-LOX-independent pathways also contribute to PLY-triggered pulmonary inflammation. These data indicate that PLY is an important factor in promoting hepoxilin A3-dependent neutrophil recruitment across pulmonary epithelium in a pore-dependent fashion.
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Affiliation(s)
- Walter Adams
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111
- Department of Biological Sciences, San Jose State University, San Jose, CA 95192
| | - Rudra Bhowmick
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111
| | - Elsa N Bou Ghanem
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111
| | - Kristin Wade
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Mikhail Shchepetov
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Jeffrey N Weiser
- Department of Microbiology, New York University School of Medicine, New York, NY 10016; and
| | - Beth A McCormick
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655
| | - Rodney K Tweten
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111;
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29
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Lamb CL, Price E, Field KP, Dayton C, McIndoo ER, Katahira EJ, Stevens DL, Hobdey SE. Enrichment of Antigen-Specific Class-Switched B Cells from Individuals Naturally Immunized by Infection with Group A Streptococcus. mSphere 2019; 4:e00598-19. [PMID: 31694896 PMCID: PMC6835209 DOI: 10.1128/msphere.00598-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/17/2019] [Indexed: 01/17/2023] Open
Abstract
The low frequency of circulating antigen-specific memory B cells is a considerable obstacle in the discovery and development of human monoclonal antibodies for therapeutic application. Here, we evaluate two solid-phase isolation methods to enrich the number of antigen-specific B cells from individuals naturally immunized against streptolysin O (SLO), a key virulence factor and known immunogen of group A streptococcus (GAS). Class-switched B cells obtained from individuals with a history of GAS infection were separated from peripheral blood mononuclear cells (PBMCs) by immunomagnetic methods. SLO-specific B cells were further enriched directly by binding to SLO monomers and captured by streptavidin-coated magnetic microbeads or indirectly by binding a fluorescently labeled SLO-streptavidin tetramer and captured by anti-fluorophore immunomagnetic microbeads. SLO-bound B cells were quantitated by flow cytometry and/or expanded in batch culture to determine IgG specificity. From individuals who have suffered a GAS infection ≥2 years prior, only the direct method enriched SLO-specific B cells, as determined by flow cytometry. Likewise, in batch culture, B cells isolated by the direct method resulted in an average of 375-fold enrichment in anti-SLO IgG, while no enrichment was observed for B cells isolated by the indirect method. The direct method established here provides a simple approach to increase low-frequency antigen-specific B cell populations supporting many downstream applications, such as immortalization of B cells, cloning of immunoglobulin genes, or purification of antibodies from supernatant for future study. Overall, this process is efficient, is inexpensive, and can be applied to many naturally immunogenic antigens.IMPORTANCE Bacteria called group A streptococci can cause a variety of skin and soft tissue infections ranging from mild pharyngitis ("strep throat") to deadly necrotizing fasciitis (sometimes called "flesh-eating" disease). In each case, the development of disease and the degree of tissue damage are mediated by toxins released from the bacteria during infection. Consequently, novel therapies aimed at clearing bacterial toxins are greatly needed. One promising new treatment is the utilization of monoclonal antibodies delivered as an immunotherapeutic for toxin neutralization. However, current methods of antibody development are laborious and costly. Here, we report a method to enrich and increase the detection of highly desirable antigen-specific memory B cells from individuals previously exposed to GAS using a cost-effective and less-time-intensive strategy. We envision that this method will be incorporated into many applications supporting the development of immunotherapeutics.
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Affiliation(s)
- Cheri L Lamb
- Infectious Diseases Section, Veteran Affairs Medical Center, Boise, Idaho, USA
- Idaho Veterans Research and Education Foundation, Boise, Idaho, USA
| | - Emily Price
- Infectious Diseases Section, Veteran Affairs Medical Center, Boise, Idaho, USA
- Idaho Veterans Research and Education Foundation, Boise, Idaho, USA
| | - Kevin P Field
- Infectious Diseases Section, Veteran Affairs Medical Center, Boise, Idaho, USA
- Idaho Veterans Research and Education Foundation, Boise, Idaho, USA
| | - Christopher Dayton
- Infectious Diseases Section, Veteran Affairs Medical Center, Boise, Idaho, USA
- Idaho Veterans Research and Education Foundation, Boise, Idaho, USA
| | - Eric R McIndoo
- Infectious Diseases Section, Veteran Affairs Medical Center, Boise, Idaho, USA
| | - Eva J Katahira
- Infectious Diseases Section, Veteran Affairs Medical Center, Boise, Idaho, USA
| | - Dennis L Stevens
- Infectious Diseases Section, Veteran Affairs Medical Center, Boise, Idaho, USA
- Idaho Veterans Research and Education Foundation, Boise, Idaho, USA
- University of Washington School of Medicine, Seattle, Washington, USA
| | - Sarah E Hobdey
- Infectious Diseases Section, Veteran Affairs Medical Center, Boise, Idaho, USA
- Idaho Veterans Research and Education Foundation, Boise, Idaho, USA
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30
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pH-triggered endosomal escape of pore-forming Listeriolysin O toxin-coated gold nanoparticles. J Nanobiotechnology 2019; 17:108. [PMID: 31623647 PMCID: PMC6798460 DOI: 10.1186/s12951-019-0543-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/03/2019] [Indexed: 01/29/2023] Open
Abstract
Background A major bottleneck in drug delivery is the breakdown and degradation of the delivery system through the endosomal/lysosomal network of the host cell, hampering the correct delivery of the drug of interest. In nature, the bacterial pathogen Listeria monocytogenes has developed a strategy to secrete Listeriolysin O (LLO) toxin as a tool to escape the eukaryotic lysosomal system upon infection, allowing it to grow and proliferate unharmed inside the host cell. Results As a “proof of concept”, we present here the use of purified His-LLO H311A mutant protein and its conjugation on the surface of gold nanoparticles to promote the lysosomal escape of 40 nm-sized nanoparticles in mouse embryonic fibroblasts. Surface immobilization of LLO was achieved after specific functionalization of the nanoparticles with nitrile acetic acid, enabling the specific binding of histidine-tagged proteins. Conclusions Endosomal acidification leads to release of the LLO protein from the nanoparticle surface and its self-assembly into a 300 Å pore that perforates the endosomal/lysosomal membrane, enabling the escape of nanoparticles.
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31
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Omersa N, Podobnik M, Anderluh G. Inhibition of Pore-Forming Proteins. Toxins (Basel) 2019; 11:E545. [PMID: 31546810 PMCID: PMC6784129 DOI: 10.3390/toxins11090545] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/27/2019] [Accepted: 09/10/2019] [Indexed: 12/16/2022] Open
Abstract
Perforation of cellular membranes by pore-forming proteins can affect cell physiology, tissue integrity, or immune response. Since many pore-forming proteins are toxins or highly potent virulence factors, they represent an attractive target for the development of molecules that neutralize their actions with high efficacy. There has been an assortment of inhibitors developed to specifically obstruct the activity of pore-forming proteins, in addition to vaccination and antibiotics that serve as a plausible treatment for the majority of diseases caused by bacterial infections. Here we review a wide range of potential inhibitors that can specifically and effectively block the activity of pore-forming proteins, from small molecules to more specific macromolecular systems, such as synthetic nanoparticles, antibodies, antibody mimetics, polyvalent inhibitors, and dominant negative mutants. We discuss their mechanism of inhibition, as well as advantages and disadvantages.
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Affiliation(s)
- Neža Omersa
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
| | - Marjetka Podobnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
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32
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Zhao Q, Wang J, Yin C, Zhang P, Zhang J, Shi M, Shen K, Xiao Y, Zhao Y, Yang X, Zhang Y. Near-Infrared Light-Sensitive Nano Neuro-Immune Blocker Capsule Relieves Pain and Enhances the Innate Immune Response for Necrotizing Infection. NANO LETTERS 2019; 19:5904-5914. [PMID: 31389707 DOI: 10.1021/acs.nanolett.9b01459] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Sensory neurons promote profound suppressive effects on neutrophils during Streptococcus pyogenes infection and contribute to the pathogenesis of necrotizing infection ("flesh-eating disease"). Thus, the development of new antibacterial agents for necrotizing infection is promising because of the clear streptococcal neuro-immune communication. Herein, based on the immune escape membrane exterior and competitive membrane functions of the glioma cell membrane, a novel nano neuro-immune blocker capsule was designed to prevent neuronal activation and improve neutrophil immune responses for necrotizing infection. These nano neuro-immune blockers could neutralize streptolysin S, suppress neuron pain conduction and calcitonin gene-related peptide release, and recruit neutrophils to the infection site, providing a strong therapeutic effect against necrotizing infection. Furthermore, nano neuro-immune blockers could serve as an effective inflammatory regulator and antibacterial agent via photothermal effects under near-infrared irradiation. In the Streptococcus pyogenes-induced necrotizing fasciitis mouse model, nano neuro-immune blockers showed significant therapeutic efficacy by ameliorating sensitivity to pain and promoting the antibacterial effect of neutrophils.
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Affiliation(s)
- Qin Zhao
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology , Wuhan University , Wuhan 430079 , China
| | - Jinyang Wang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology , Wuhan University , Wuhan 430079 , China
| | - Chengcheng Yin
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology , Wuhan University , Wuhan 430079 , China
| | - Peng Zhang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology , Wuhan University , Wuhan 430079 , China
| | - Jinglun Zhang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology , Wuhan University , Wuhan 430079 , China
| | - Miusi Shi
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology , Wuhan University , Wuhan 430079 , China
| | - Kailun Shen
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology , Wuhan University , Wuhan 430079 , China
| | - Yin Xiao
- Institute of Health and Biomedical Innovation , Queensland University of Technology , Kelvin Grove , Queensland 4059 , Australia
| | - Yanbing Zhao
- National Engineering Research Center for Nanomedicine, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, College of Life Science and Technology , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Xiangliang Yang
- National Engineering Research Center for Nanomedicine, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, College of Life Science and Technology , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Yufeng Zhang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine, Ministry of Education, School and Hospital of Stomatology , Wuhan University , Wuhan 430079 , China
- Medical Research Institute, School of Medicine , Wuhan University , Wuhan , 430071 , China
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33
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Chapeton-Montes D, Plourde L, Bouchier C, Ma L, Diancourt L, Criscuolo A, Popoff MR, Brüggemann H. The population structure of Clostridium tetani deduced from its pan-genome. Sci Rep 2019; 9:11220. [PMID: 31375706 PMCID: PMC6677821 DOI: 10.1038/s41598-019-47551-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 07/16/2019] [Indexed: 01/04/2023] Open
Abstract
Clostridium tetani produces a potent neurotoxin, the tetanus neurotoxin (TeNT) that is responsible for the worldwide neurological disease tetanus, but which can be efficiently prevented by vaccination with tetanus toxoid. Until now only one type of TeNT has been characterized and very little information exists about the heterogeneity among C. tetani strains. We report here the genome sequences of 26 C. tetani strains, isolated between 1949 and 2017 and obtained from different locations. Genome analyses revealed that the C. tetani population is distributed in two phylogenetic clades, a major and a minor one, with no evidence for clade separation based on geographical origin or time of isolation. The chromosome of C. tetani is highly conserved; in contrast, the TeNT-encoding plasmid shows substantial heterogeneity. TeNT itself is highly conserved among all strains; the most relevant difference is an insertion of four amino acids in the C-terminal receptor-binding domain in four strains that might impact on receptor-binding properties. Other putative virulence factors, including tetanolysin and collagenase, are encoded in all genomes. This study highlights the population structure of C. tetani and suggests that tetanus-causing strains did not undergo extensive evolutionary diversification, as judged from the high conservation of its main virulence factors.
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Affiliation(s)
| | | | | | - Laurence Ma
- Genomic Platform, Biomics, Institut Pasteur, Paris, France
| | - Laure Diancourt
- CNR Bactéries anaérobies Botulisme, Institut Pasteur, Paris, France
| | - Alexis Criscuolo
- Hub Bioinformatique Biostatistique, Institut Pasteur, Paris, France
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34
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Nagahama M, Takehara M, Rood JI. Histotoxic Clostridial Infections. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0024-2018. [PMID: 31350831 PMCID: PMC10957196 DOI: 10.1128/microbiolspec.gpp3-0024-2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Indexed: 01/01/2023] Open
Abstract
The pathogenesis of clostridial myonecrosis or gas gangrene involves an interruption to the blood supply to the infected tissues, often via a traumatic wound, anaerobic growth of the infecting clostridial cells, the production of extracellular toxins, and toxin-mediated cell and tissue damage. This review focuses on host-pathogen interactions in Clostridium perfringens-mediated and Clostridium septicum-mediated myonecrosis. The major toxins involved are C. perfringens α-toxin, which has phospholipase C and sphingomyelinase activity, and C. septicum α-toxin, a β-pore-forming toxin that belongs to the aerolysin family. Although these toxins are cytotoxic, their effects on host cells are quite complex, with a range of intracellular cell signaling pathways induced by their action on host cell membranes.
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Affiliation(s)
- Masahiro Nagahama
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan
| | - Masaya Takehara
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan
| | - Julian I Rood
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
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35
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González-Bullón D, Uribe KB, Largo E, Guembelzu G, García-Arribas AB, Martín C, Ostolaza H. Membrane Permeabilization by Bordetella Adenylate Cyclase Toxin Involves Pores of Tunable Size. Biomolecules 2019; 9:biom9050183. [PMID: 31083482 PMCID: PMC6572617 DOI: 10.3390/biom9050183] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/02/2019] [Accepted: 05/05/2019] [Indexed: 01/27/2023] Open
Abstract
RTX (Repeats in ToXin) pore-forming toxins constitute an expanding family of exoproteins secreted by many Gram-negative bacteria and involved in infectious diseases caused by said pathogens. Despite the relevance in the host/pathogen interactions, the structure and characteristics of the lesions formed by these toxins remain enigmatic. Here, we capture the first direct nanoscale pictures of lytic pores formed by an RTX toxin, the Adenylate cyclase (ACT), secreted by the whooping cough bacterium Bordetella pertussis. We reveal that ACT associates into growing-size oligomers of variable stoichiometry and heterogeneous architecture (lines, arcs, and rings) that pierce the membrane, and that, depending on the incubation time and the toxin concentration, evolve into large enough “holes” so as to allow the flux of large molecular mass solutes, while vesicle integrity is preserved. We also resolve ACT assemblies of similar variable stoichiometry in the cell membrane of permeabilized target macrophages, proving that our model system recapitulates the process of ACT permeabilization in natural membranes. Based on our data we propose a non-concerted monomer insertion and sequential mechanism of toroidal pore formation by ACT. A size-tunable pore adds a new regulatory element to ACT-mediated cytotoxicity, with different pore sizes being putatively involved in different physiological scenarios or cell types.
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Affiliation(s)
- David González-Bullón
- Biofisika Institute, (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of Basque Country (UPV/EHU) Aptdo. 644, 48080 Bilbao, Spain.
| | - Kepa B Uribe
- Biofisika Institute, (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of Basque Country (UPV/EHU) Aptdo. 644, 48080 Bilbao, Spain.
| | - Eneko Largo
- Biofisika Institute, (UPV/EHU, CSIC) and Department of Biochemistry and Molecular Biology, University of Basque Country (UPV/EHU) Aptdo. 644, 48080 Bilbao, Spain.
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36
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Marinko J, Huang H, Penn WD, Capra JA, Schlebach JP, Sanders CR. Folding and Misfolding of Human Membrane Proteins in Health and Disease: From Single Molecules to Cellular Proteostasis. Chem Rev 2019; 119:5537-5606. [PMID: 30608666 PMCID: PMC6506414 DOI: 10.1021/acs.chemrev.8b00532] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Indexed: 12/13/2022]
Abstract
Advances over the past 25 years have revealed much about how the structural properties of membranes and associated proteins are linked to the thermodynamics and kinetics of membrane protein (MP) folding. At the same time biochemical progress has outlined how cellular proteostasis networks mediate MP folding and manage misfolding in the cell. When combined with results from genomic sequencing, these studies have established paradigms for how MP folding and misfolding are linked to the molecular etiologies of a variety of diseases. This emerging framework has paved the way for the development of a new class of small molecule "pharmacological chaperones" that bind to and stabilize misfolded MP variants, some of which are now in clinical use. In this review, we comprehensively outline current perspectives on the folding and misfolding of integral MPs as well as the mechanisms of cellular MP quality control. Based on these perspectives, we highlight new opportunities for innovations that bridge our molecular understanding of the energetics of MP folding with the nuanced complexity of biological systems. Given the many linkages between MP misfolding and human disease, we also examine some of the exciting opportunities to leverage these advances to address emerging challenges in the development of therapeutics and precision medicine.
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Affiliation(s)
- Justin
T. Marinko
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Wesley D. Penn
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - John A. Capra
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37245, United States
| | - Jonathan P. Schlebach
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
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37
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Abstract
The cholesterol-dependent cytolysin (CDC) genes are present in bacterial species that span terrestrial, vertebrate, and invertebrate niches, which suggests that they have evolved to function under widely different environmental conditions. Using a combination of biophysical and crystallographic approaches, we reveal that the relative stability of an intramolecular interface in the archetype CDC perfringolysin O (PFO) plays a central role in regulating its pore-forming properties. The disruption of this interface allows the formation of the membrane spanning β-barrel pore in all CDCs. We show here that the relative strength of the stabilizing forces at this interface directly impacts the energy barrier posed by the transition state for pore formation, as reflected in the Arrhenius activation energy (Ea) for pore formation. This change directly impacts the kinetics and temperature dependence of pore formation. We further show that the interface structure in a CDC from a terrestrial species enables it to function efficiently across a wide range of temperatures by minimizing changes in the strength of the transition state barrier to pore formation. These studies establish a paradigm that CDCs, and possibly other β-barrel pore-forming proteins/toxins, can evolve significantly different pore-forming properties by altering the stability of this transitional interface, which impacts the kinetic parameters and temperature dependence of pore formation.IMPORTANCE The cholesterol-dependent cytolysins (CDCs) are the archetype for the superfamily of oligomeric pore-forming proteins that includes the membrane attack complex/perforin (MACPF) family of immune defense proteins and the stonefish venom toxins (SNTX). The CDC/MACPF/SNTX family exhibits a common protein fold, which forms a membrane-spanning β-barrel pore. We show that changing the relative stability of an extensive intramolecular interface within this fold, which is necessarily disrupted to form the large β-barrel pore, dramatically alters the kinetic and temperature-dependent properties of CDC pore formation. These studies show that the CDCs and other members of the CDC/MACPF/SNTX superfamily have the capacity to significantly alter their pore-forming properties to function under widely different environmental conditions encountered by these species.
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38
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Changes in the asymmetric distribution of cholesterol in the plasma membrane influence streptolysin O pore formation. Sci Rep 2019; 9:4548. [PMID: 30872611 PMCID: PMC6418215 DOI: 10.1038/s41598-019-39973-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/21/2019] [Indexed: 01/23/2023] Open
Abstract
ATP-binding cassette A1 (ABCA1) plays a key role in generating high-density lipoprotein (HDL) and preventing atherosclerosis. ABCA1 exports cholesterol and phospholipid to apolipoprotein A-I (apoA-I) in serum to generate HDL. We found that streptolysin O (SLO), a cholesterol-dependent pore-forming toxin, barely formed pores in ABCA1-expressing cells, even in the absence of apoA-I. Neither cholesterol content in cell membranes nor the amount of SLO bound to cells was affected by ABCA1. On the other hand, binding of the D4 domain of perfringolysin O (PFO) to ABCA1-expressing cells increased, suggesting that the amount of cholesterol in the outer leaflet of the plasma membrane (PM) increased and that the cholesterol dependences of these two toxins differ. Addition of cholesterol to the PM by the MβCD-cholesterol complex dramatically restored SLO pore formation in ABCA1-expressing cells. Therefore, exogenous expression of ABCA1 causes reduction in the cholesterol level in the inner leaflet, thereby suppressing SLO pore formation.
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Abstract
ABSTRACT
Streptococcus pyogenes
(i.e., the group A
Streptococcus
) is a human-restricted and versatile bacterial pathogen that produces an impressive arsenal of both surface-expressed and secreted virulence factors. Although surface-expressed virulence factors are clearly vital for colonization, establishing infection, and the development of disease, the secreted virulence factors are likely the major mediators of tissue damage and toxicity seen during active infection. The collective exotoxin arsenal of
S. pyogenes
is rivaled by few bacterial pathogens and includes extracellular enzymes, membrane active proteins, and a variety of toxins that specifically target both the innate and adaptive arms of the immune system, including the superantigens; however, despite their role in
S. pyogenes
disease, each of these virulence factors has likely evolved with humans in the context of asymptomatic colonization and transmission. In this article, we focus on the biology of the true secreted exotoxins of the group A
Streptococcus
, as well as their roles in the pathogenesis of human disease.
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40
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Nguyen BN, Peterson BN, Portnoy DA. Listeriolysin O: A phagosome-specific cytolysin revisited. Cell Microbiol 2019; 21:e12988. [PMID: 30511471 DOI: 10.1111/cmi.12988] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/02/2018] [Accepted: 11/09/2018] [Indexed: 12/17/2022]
Abstract
Listeriolysin O (LLO) is an essential determinant of Listeria monocytogenes pathogenesis that mediates the escape of L. monocytogenes from host cell vacuoles, thereby allowing replication in the cytosol without causing appreciable cell death. As a member of the cholesterol-dependent cytolysin (CDC) family of pore-forming toxins, LLO is unique in that it is secreted by a facultative intracellular pathogen, whereas all other CDCs are produced by pathogens that are largely extracellular. Replacement of LLO with other CDCs results in strains that are extremely cytotoxic and 10,000-fold less virulent in mice. LLO has structural and regulatory features that allow it to function intracellularly without causing cell death, most of which map to a unique N-terminal region of LLO referred to as the proline, glutamic acid, serine, threonine (PEST)-like sequence. Yet, while LLO has unique properties required for its intracellular site of action, extracellular LLO, like other CDCs, affects cells in a myriad of ways. Because all CDCs form pores in cholesterol-containing membranes that lead to rapid Ca2+ influx and K+ efflux, they consequently trigger a wide range of host cell responses, including mitogen-activated protein kinase activation, histone modification, and caspase-1 activation. There is no debate that extracellular LLO, like all other CDCs, can stimulate multiple cellular activities, but the primary question we wish to address in this perspective is whether these activities contribute to L. monocytogenes pathogenesis.
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Affiliation(s)
- Brittney N Nguyen
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, California
| | - Bret N Peterson
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, California
| | - Daniel A Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California
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41
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Ray S, Thapa R, Keyel PA. Multiple Parameters Beyond Lipid Binding Affinity Drive Cytotoxicity of Cholesterol-Dependent Cytolysins. Toxins (Basel) 2018; 11:toxins11010001. [PMID: 30577571 PMCID: PMC6356533 DOI: 10.3390/toxins11010001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/14/2018] [Accepted: 12/18/2018] [Indexed: 02/06/2023] Open
Abstract
The largest superfamily of bacterial virulence factors is pore-forming toxins (PFTs). PFTs are secreted by both pathogenic and non-pathogenic bacteria. PFTs sometimes kill or induce pro-pathogen signaling in mammalian cells, all primarily through plasma membrane perforation, though the parameters that determine these outcomes are unclear. Membrane binding, calcium influx, pore size, and membrane repair are factors that influence PFT cytotoxicity. To test the contribution of membrane binding to cytotoxicity and repair, we compared the closely related, similarly-sized PFTs Perfringolysin O (PFO) from Clostridium perfringens and Streptolysin O (SLO) from Streptococcus pyogenes. Cell death kinetics for PFO and SLO were different because PFO increased in cytotoxicity over time. We introduced known L3 loop mutations that swap binding affinity between toxins and measured hemolytic activity, nucleated cell death kinetics and membrane repair using viability assays, and live cell imaging. Altered hemolytic activity was directly proportional to toxin binding affinity. In contrast, L3 loop alterations reduced nucleated cell death, and they had limited effects on cytotoxicity kinetics and membrane repair. This suggests other toxin structural features, like oligomerization, drives these parameters. Overall, these findings suggest that repair mechanisms and toxin oligomerization add constraints beyond membrane binding on toxin evolution and activity against nucleated cells.
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Affiliation(s)
- Sucharit Ray
- Department of Biological Sciences, College of Arts and Sciences, Texas Tech University, Box 43131, Lubbock, TX 79409, USA.
| | - Roshan Thapa
- Department of Biological Sciences, College of Arts and Sciences, Texas Tech University, Box 43131, Lubbock, TX 79409, USA.
| | - Peter A Keyel
- Department of Biological Sciences, College of Arts and Sciences, Texas Tech University, Box 43131, Lubbock, TX 79409, USA.
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42
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Kozorog M, Sani M, Separovic F, Anderluh G. Listeriolysin O Binding Affects Cholesterol and Phospholipid Acyl Chain Dynamics in Fluid Cholesterol‐Rich Bilayers. Chemistry 2018; 24:14220-14225. [DOI: 10.1002/chem.201802575] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 01/26/2023]
Affiliation(s)
- Mirijam Kozorog
- Department of Molecular Biology and NanobiotechnologyNational Institute of Chemistry Hajdrihova 19 1000 Ljubljana Slovenia
| | - Marc‐Antoine Sani
- School of ChemistryBio21 InstituteThe University of Melbourne VIC 3010 Australia
| | - Frances Separovic
- School of ChemistryBio21 InstituteThe University of Melbourne VIC 3010 Australia
| | - Gregor Anderluh
- Department of Molecular Biology and NanobiotechnologyNational Institute of Chemistry Hajdrihova 19 1000 Ljubljana Slovenia
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43
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Stewart MP, Langer R, Jensen KF. Intracellular Delivery by Membrane Disruption: Mechanisms, Strategies, and Concepts. Chem Rev 2018; 118:7409-7531. [PMID: 30052023 PMCID: PMC6763210 DOI: 10.1021/acs.chemrev.7b00678] [Citation(s) in RCA: 382] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intracellular delivery is a key step in biological research and has enabled decades of biomedical discoveries. It is also becoming increasingly important in industrial and medical applications ranging from biomanufacture to cell-based therapies. Here, we review techniques for membrane disruption-based intracellular delivery from 1911 until the present. These methods achieve rapid, direct, and universal delivery of almost any cargo molecule or material that can be dispersed in solution. We start by covering the motivations for intracellular delivery and the challenges associated with the different cargo types-small molecules, proteins/peptides, nucleic acids, synthetic nanomaterials, and large cargo. The review then presents a broad comparison of delivery strategies followed by an analysis of membrane disruption mechanisms and the biology of the cell response. We cover mechanical, electrical, thermal, optical, and chemical strategies of membrane disruption with a particular emphasis on their applications and challenges to implementation. Throughout, we highlight specific mechanisms of membrane disruption and suggest areas in need of further experimentation. We hope the concepts discussed in our review inspire scientists and engineers with further ideas to improve intracellular delivery.
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Affiliation(s)
- Martin P. Stewart
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
- The Koch Institute for Integrative Cancer Research,
Massachusetts Institute of Technology, Cambridge, USA
| | - Robert Langer
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
- The Koch Institute for Integrative Cancer Research,
Massachusetts Institute of Technology, Cambridge, USA
| | - Klavs F. Jensen
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
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44
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Arcanobacterium haemolyticum Phospholipase D Enzymatic Activity Promotes the Hemolytic Activity of the Cholesterol-Dependent Cytolysin Arcanolysin. Toxins (Basel) 2018; 10:toxins10060213. [PMID: 29882842 PMCID: PMC6024514 DOI: 10.3390/toxins10060213] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/14/2018] [Accepted: 05/18/2018] [Indexed: 02/06/2023] Open
Abstract
Arcanolysin, produced by the human pathogen Arcanobacterium haemolyticum, is a cholesterol-dependent cytolysin. To mediate the pore-formation process, arcanolysin is secreted by A. haemolyticum and then must interact with cholesterol embedded within a host membrane. However, arcanolysin must compete with membrane components, such as the phospholipid sphingomyelin, to interact with cholesterol and form pores. Cholesterol forms transient hydrogen bonds with the extracellular portion of sphingomyelin, shielding cholesterol from extracellular factors, including arcanolysin. A. haemolyticum also produces a sphingomyelin-specific phospholipase D, which removes the choline head from sphingomyelin, leaving cyclic-ceramide phosphate and eliminating the potential for cholesterol sequestration. We hypothesized that the enzymatic activity of phospholipase D decreases sphingomyelin-mediated cholesterol sequestration and increases cholesterol accessibility for arcanolysin. Using purified arcanolysin and phospholipase D, we demonstrate that the enzymatic activity of phospholipase D is necessary to promote arcanolysin-mediated hemolysis in both time- and concentration-dependent manners. Phospholipase D promotion of arcanolysin-mediated cytotoxicity was confirmed in Detroit 562 epithelial cells. Furthermore, we determined that incubating phospholipase D with erythrocytes corresponds with an increase in the amount of arcanolysin bound to host membranes. This observation suggests that phospholipase D promotes arcanolysin-mediated cytotoxicity by increasing the ability of arcanolysin to bind to a host membrane.
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45
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Blocking Neuronal Signaling to Immune Cells Treats Streptococcal Invasive Infection. Cell 2018; 173:1083-1097.e22. [PMID: 29754819 DOI: 10.1016/j.cell.2018.04.006] [Citation(s) in RCA: 254] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 02/08/2018] [Accepted: 04/03/2018] [Indexed: 11/21/2022]
Abstract
The nervous system, the immune system, and microbial pathogens interact closely at barrier tissues. Here, we find that a bacterial pathogen, Streptococcus pyogenes, hijacks pain and neuronal regulation of the immune response to promote bacterial survival. Necrotizing fasciitis is a life-threatening soft tissue infection in which "pain is out of proportion" to early physical manifestations. We find that S. pyogenes, the leading cause of necrotizing fasciitis, secretes streptolysin S (SLS) to directly activate nociceptor neurons and produce pain during infection. Nociceptors, in turn, release the neuropeptide calcitonin gene-related peptide (CGRP) into infected tissues, which inhibits the recruitment of neutrophils and opsonophagocytic killing of S. pyogenes. Botulinum neurotoxin A and CGRP antagonism block neuron-mediated suppression of host defense, thereby preventing and treating S. pyogenes necrotizing infection. We conclude that targeting the peripheral nervous system and blocking neuro-immune communication is a promising strategy to treat highly invasive bacterial infections. VIDEO ABSTRACT.
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46
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Kozorog M, Sani MA, Lenarčič Živković M, Ilc G, Hodnik V, Separovic F, Plavec J, Anderluh G. 19F NMR studies provide insights into lipid membrane interactions of listeriolysin O, a pore forming toxin from Listeria monocytogenes. Sci Rep 2018; 8:6894. [PMID: 29720597 PMCID: PMC5931962 DOI: 10.1038/s41598-018-24692-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/28/2018] [Indexed: 11/12/2022] Open
Abstract
Listeria monocytogenes is a mammalian pathogen that causes gastroenteritis, miscarriages and infections of the central nervous system in immunocompromised individuals. Its main virulence factor is listeriolysin O (LLO), a pore-forming cholesterol-dependent cytolysin (CDC), which enables bacterial escape from the phagolysosome and contributes to bacterial pathogenicity. Details of cholesterol (Chol) recognition and membrane binding mechanisms by LLO are still not known. Here we used 19F-NMR spectroscopy in order to assess LLO-Chol interactions in solution and in a Chol-rich membrane environment. LLO has six tryptophan residues located in the region of the molecule that is first in contact with lipid membranes. 19F-LLO, which contained 5-fluoro-tryptophans, was prepared by using isotopic labelling in an E. coli expression system. Signals in the 19F-NMR spectrum of 19F-LLO were unambiguously assigned by using a series of single Trp → Phe point mutations. The results employing various cholesterol preparations in solution indicate that tryptophan residues are not directly involved in Chol binding in solution. However, significant chemical shift changes were observed upon LLO binding to Chol-rich membranes, highlighting the role of tryptophan residues in membrane interactions (W512) and oligomerisation (W189 and W489).
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Affiliation(s)
- Mirijam Kozorog
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia.,Graduate School of Biomedicine, Medical faculty, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Gregor Ilc
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Vesna Hodnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia.,EN-FIST Centre of Excellence, Trg Osvobodilne fronte 13, 1001, Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia.
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47
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Cholesterol-dependent cytolysins impair pro-inflammatory macrophage responses. Sci Rep 2018; 8:6458. [PMID: 29691463 PMCID: PMC5915385 DOI: 10.1038/s41598-018-24955-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/11/2018] [Indexed: 12/20/2022] Open
Abstract
Necrotizing soft tissue infections are lethal polymicrobial infections. Two key microbes that cause necrotizing soft tissue infections are Streptococcus pyogenes and Clostridium perfringens. These pathogens evade innate immunity using multiple virulence factors, including cholesterol-dependent cytolysins (CDCs). CDCs are resisted by mammalian cells through the sequestration and shedding of pores during intrinsic membrane repair. One hypothesis is that vesicle shedding promotes immune evasion by concomitantly eliminating key signaling proteins present in cholesterol-rich microdomains. To test this hypothesis, murine macrophages were challenged with sublytic CDC doses. CDCs suppressed LPS or IFNγ-stimulated TNFα production and CD69 and CD86 surface expression. This suppression was cell intrinsic. Two membrane repair pathways, patch repair and intrinsic repair, might mediate TNFα suppression. However, patch repair did not correlate with TNFα suppression. Intrinsic repair partially contributed to macrophage dysfunction because TLR4 and the IFNγR were partially shed following CDC challenge. Intrinsic repair was not sufficient for suppression, because pore formation was also required. These findings suggest that even when CDCs fail to kill cells, they may impair innate immune signaling responses dependent on cholesterol-rich microdomains. This is one potential mechanism to explain the lethality of S. pyogenes and C. perfringens during necrotizing soft tissue infections.
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48
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Rezelj S, Kozorog M, Švigelj T, Ulrih NP, Žnidaršič N, Podobnik M, Anderluh G. Cholesterol Enriched Archaeosomes as a Molecular System for Studying Interactions of Cholesterol-Dependent Cytolysins with Membranes. J Membr Biol 2018; 251:491-505. [DOI: 10.1007/s00232-018-0018-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 02/05/2018] [Indexed: 12/31/2022]
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Mondal AK, Sreekumar A, Kundu N, Kathuria R, Verma P, Gandhi S, Chattopadhyay K. Structural Basis and Functional Implications of the Membrane Pore-Formation Mechanisms of Bacterial Pore-Forming Toxins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1112:281-291. [DOI: 10.1007/978-981-13-3065-0_19] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Morgan BP, Boyd C, Bubeck D. Molecular cell biology of complement membrane attack. Semin Cell Dev Biol 2017; 72:124-132. [PMID: 28647534 DOI: 10.1016/j.semcdb.2017.06.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 06/10/2017] [Accepted: 06/14/2017] [Indexed: 12/11/2022]
Abstract
The membrane attack complex (MAC) is the pore-forming toxin of the complement system, a relatively early evolutionary acquisition that confers upon complement the capacity to directly kill pathogens. The MAC is more than just a bactericidal missile, having the capacity when formed on self-cells to initiate a host of cell activation events that can have profound consequences for tissue homeostasis in the face of infection or injury. Although the capacity of complement to directly kill pathogens has been recognised for over a century, and the pore-forming killing mechanism for at least 50 years, there remains considerable uncertainty regarding precisely how MAC mediates its killing and cell activation activities. A recent burst of new information on MAC structure provides context and opportunity to re-assess the ways in which MAC kills bacteria and modulates cell functions. In this brief review we will describe key aspects of MAC evolution, function and structure and seek to use the new structural information to better explain how the MAC works.
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Affiliation(s)
- B Paul Morgan
- Systems Immunity University Research Institute, Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF144XN, UK.
| | - Courtney Boyd
- Faculty of Natural Sciences, Department of Life Sciences, Imperial College, 506 Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Doryen Bubeck
- Faculty of Natural Sciences, Department of Life Sciences, Imperial College, 506 Sir Ernst Chain Building, London SW7 2AZ, UK
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