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Abeyawardhane DL, Sevdalis SE, Adipietro KA, Godoy-Ruiz R, Varney KM, Nawaz IF, Spittel AX, Rustandi RR, Silin VI, des Georges A, Pozharski E, Weber DJ. Membrane binding and pore formation is Ca 2+ -dependent for the Clostridioides difficile binary toxin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.18.553786. [PMID: 37645845 PMCID: PMC10462154 DOI: 10.1101/2023.08.18.553786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
The C. difficile binary toxin (CDT) enters host cells via endosomal delivery like many other 'AB'-type binary toxins. In this study, the cell-binding component of CDT, termed CDTb, was found to bind and form pores in lipid bilayers upon depleting free Ca 2+ ion concentrations, and not by lowering pH, as found for other binary toxins (i.e., anthrax). Cryoelectron microscopy, nuclear magnetic resonance spectroscopy, surface plasmon resonance, electrochemical impedance spectroscopy, CDT toxicity studies, and site directed mutagenesis show that dissociation of Ca 2+ from a single site in receptor binding domain 1 (RBD1) of CDTb is consistent with a molecular mechanism in which Ca 2+ dissociation from RBD1 induces a "trigger" via conformational exchange that enables CDTb to bind and form pores in endosomal membrane bilayers as free Ca 2+ concentrations decrease during CDT endosomal delivery.
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Abeyawardhane DL, Godoy-Ruiz R, Adipietro KA, Varney KM, Rustandi RR, Pozharski E, Weber DJ. The Importance of Therapeutically Targeting the Binary Toxin from Clostridioides difficile. Int J Mol Sci 2021; 22:2926. [PMID: 33805767 PMCID: PMC8001090 DOI: 10.3390/ijms22062926] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 02/06/2023] Open
Abstract
Novel therapeutics are needed to treat pathologies associated with the Clostridioides difficile binary toxin (CDT), particularly when C. difficile infection (CDI) occurs in the elderly or in hospitalized patients having illnesses, in addition to CDI, such as cancer. While therapies are available to block toxicities associated with the large clostridial toxins (TcdA and TcdB) in this nosocomial disease, nothing is available yet to treat toxicities arising from strains of CDI having the binary toxin. Like other binary toxins, the active CDTa catalytic subunit of CDT is delivered into host cells together with an oligomeric assembly of CDTb subunits via host cell receptor-mediated endocytosis. Once CDT arrives in the host cell's cytoplasm, CDTa catalyzes the ADP-ribosylation of G-actin leading to degradation of the cytoskeleton and rapid cell death. Although a detailed molecular mechanism for CDT entry and host cell toxicity is not yet fully established, structural and functional resemblances to other binary toxins are described. Additionally, unique conformational assemblies of individual CDT components are highlighted herein to refine our mechanistic understanding of this deadly toxin as is needed to develop effective new therapeutic strategies for treating some of the most hypervirulent and lethal strains of CDT-containing strains of CDI.
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Affiliation(s)
- Dinendra L. Abeyawardhane
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (D.L.A.); (R.G.-R.); (K.A.A.); (K.M.V.); (E.P.)
- Baltimore—Institute for Bioscience and Biotechnology Research, University of Maryland-Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Raquel Godoy-Ruiz
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (D.L.A.); (R.G.-R.); (K.A.A.); (K.M.V.); (E.P.)
- Baltimore—Institute for Bioscience and Biotechnology Research, University of Maryland-Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kaylin A. Adipietro
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (D.L.A.); (R.G.-R.); (K.A.A.); (K.M.V.); (E.P.)
- The Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kristen M. Varney
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (D.L.A.); (R.G.-R.); (K.A.A.); (K.M.V.); (E.P.)
- Baltimore—Institute for Bioscience and Biotechnology Research, University of Maryland-Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | | | - Edwin Pozharski
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (D.L.A.); (R.G.-R.); (K.A.A.); (K.M.V.); (E.P.)
- Baltimore—Institute for Bioscience and Biotechnology Research, University of Maryland-Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - David J. Weber
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (D.L.A.); (R.G.-R.); (K.A.A.); (K.M.V.); (E.P.)
- Baltimore—Institute for Bioscience and Biotechnology Research, University of Maryland-Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Yamada T, Yoshida T, Kawamoto A, Mitsuoka K, Iwasaki K, Tsuge H. Cryo-EM structures reveal translocational unfolding in the clostridial binary iota toxin complex. Nat Struct Mol Biol 2020; 27:288-296. [PMID: 32123390 DOI: 10.1038/s41594-020-0388-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 01/17/2020] [Indexed: 11/09/2022]
Abstract
The iota toxin produced by Clostridium perfringens type E is a binary toxin comprising two independent polypeptides: Ia, an ADP-ribosyltransferase, and Ib, which is involved in cell binding and translocation of Ia across the cell membrane. Here we report cryo-EM structures of the translocation channel Ib-pore and its complex with Ia. The high-resolution Ib-pore structure demonstrates a similar structural framework to that of the catalytic ϕ-clamp of the anthrax protective antigen pore. However, the Ia-bound Ib-pore structure shows a unique binding mode of Ia: one Ia binds to the Ib-pore, and the Ia amino-terminal domain forms multiple weak interactions with two additional Ib-pore constriction sites. Furthermore, Ib-binding induces tilting and partial unfolding of the Ia N-terminal α-helix, permitting its extension to the ϕ-clamp gate. This new mechanism of N-terminal unfolding is crucial for protein translocation.
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Affiliation(s)
- Tomohito Yamada
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, Japan
| | - Toru Yoshida
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, Japan
| | - Akihiro Kawamoto
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Kaoru Mitsuoka
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka, Japan
| | - Kenji Iwasaki
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Japan
| | - Hideaki Tsuge
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, Japan. .,Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, Japan. .,Center for Molecular Research in Infectious Diseases, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, Japan.
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4
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Turner M, Tremblay O, Heney K, Lugo M, Ebeling J, Genersch E, Merrill A. Characterization of C3larvinA, a novel RhoA-targeting ADP-ribosyltransferase toxin produced by the honey bee pathogen, Paenibacillus larvae. Biosci Rep 2020; 40:BSR20193405. [PMID: 31844879 PMCID: PMC6954368 DOI: 10.1042/bsr20193405] [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: 09/19/2019] [Revised: 11/15/2019] [Accepted: 12/13/2019] [Indexed: 01/13/2023] Open
Abstract
C3larvinA is a putative virulence factor produced by Paenibacillus larvae enterobacterial-repetitive-intergenic-consensus (ERIC) III/IV (strain 11-8051). Biochemical, functional and structural analyses of C3larvinA revealed that it belongs to the C3-like mono-ADP-ribosylating toxin subgroup. Mammalian RhoA was the target substrate for its transferase activity suggesting that it may be the biological target of C3larvinA. The kinetic parameters of the NAD+ substrate for the transferase (KM = 75 ± 10 µM) and glycohydrolase (GH) (KM = 107 ± 20 µM) reactions were typical for a C3-like bacterial toxin, including the Plx2A virulence factor from Paenibacillus larvae ERIC I. Upon cytoplasmic expression in yeast, C3larvinA caused a growth-defective phenotype indicating that it is an active C3-like toxin and is cytotoxic to eukaryotic cells. The catalytic variant of the Q187-X-E189 motif in C3larvinA showed no cytotoxicity toward yeast confirming that the cytotoxicity of this factor depends on its enzymatic activity. A homology consensus model of C3larvinA with NAD+ substrate was built on the structure of Plx2A, provided additional confirmation that C3larvinA is a member of the C3-like mono-ADP-ribosylating toxin subgroup. A homology model of C3larvinA with NADH and RhoA was built on the structure of the C3cer-NADH-RhoA complex which provided further evidence that C3larvinA is a C3-like toxin that shares an identical catalytic mechanism with C3cer from Bacillus cereus. C3larvinA induced actin cytoskeleton reorganization in murine macrophages, whereas in insect cells, vacuolization and bi-nucleated cells were observed. These cellular effects are consistent with C3larvinA disrupting RhoA function by covalent modification that is shared among C3-like bacterial toxins.
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Affiliation(s)
- Madison Turner
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Olivier Tremblay
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Kayla A. Heney
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Miguel R. Lugo
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Julia Ebeling
- Institute for Bee Research, Department of Molecular Microbiology and Bee Diseases, Hohen Neuendorf 16540, Germany
| | - Elke Genersch
- Institute for Bee Research, Department of Molecular Microbiology and Bee Diseases, Hohen Neuendorf 16540, Germany
- Freie Universität Berlin, Fachbereich Veterinärmedizin, Institut für Mikrobiologie und Tierseuchen, Berlin 14163, Germany
| | - A. Rod Merrill
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Xu X, Godoy-Ruiz R, Adipietro KA, Peralta C, Ben-Hail D, Varney KM, Cook ME, Roth BM, Wilder PT, Cleveland T, Grishaev A, Neu HM, Michel SLJ, Yu W, Beckett D, Rustandi RR, Lancaster C, Loughney JW, Kristopeit A, Christanti S, Olson JW, MacKerell AD, Georges AD, Pozharski E, Weber DJ. Structure of the cell-binding component of the Clostridium difficile binary toxin reveals a di-heptamer macromolecular assembly. Proc Natl Acad Sci U S A 2020; 117:1049-1058. [PMID: 31896582 PMCID: PMC6969506 DOI: 10.1073/pnas.1919490117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Targeting Clostridium difficile infection is challenging because treatment options are limited, and high recurrence rates are common. One reason for this is that hypervirulent C. difficile strains often have a binary toxin termed the C. difficile toxin, in addition to the enterotoxins TsdA and TsdB. The C. difficile toxin has an enzymatic component, termed CDTa, and a pore-forming or delivery subunit termed CDTb. CDTb was characterized here using a combination of single-particle cryoelectron microscopy, X-ray crystallography, NMR, and other biophysical methods. In the absence of CDTa, 2 di-heptamer structures for activated CDTb (1.0 MDa) were solved at atomic resolution, including a symmetric (SymCDTb; 3.14 Å) and an asymmetric form (AsymCDTb; 2.84 Å). Roles played by 2 receptor-binding domains of activated CDTb were of particular interest since the receptor-binding domain 1 lacks sequence homology to any other known toxin, and the receptor-binding domain 2 is completely absent in other well-studied heptameric toxins (i.e., anthrax). For AsymCDTb, a Ca2+ binding site was discovered in the first receptor-binding domain that is important for its stability, and the second receptor-binding domain was found to be critical for host cell toxicity and the di-heptamer fold for both forms of activated CDTb. Together, these studies represent a starting point for developing structure-based drug-design strategies to target the most severe strains of C. difficile.
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Affiliation(s)
- Xingjian Xu
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017
- PhD Program in Biochemistry, The Graduate Center, City University of New York, New York, NY 10017
| | - Raquel Godoy-Ruiz
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Kaylin A Adipietro
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Christopher Peralta
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017
| | - Danya Ben-Hail
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017
| | - Kristen M Varney
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Mary E Cook
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Braden M Roth
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - Paul T Wilder
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | | | | | - Heather M Neu
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - Sarah L J Michel
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - Wenbo Yu
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - Dorothy Beckett
- Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742
| | | | | | | | | | | | | | - Alexander D MacKerell
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - Amedee des Georges
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017;
- PhD Program in Biochemistry, The Graduate Center, City University of New York, New York, NY 10017
- PhD Program in Chemistry, The Graduate Center, City University of New York, New York, NY 10017
- Department of Chemistry & Biochemistry, City College of New York, New York, NY 10031
| | - Edwin Pozharski
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201;
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
| | - David J Weber
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201;
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201
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6
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Gil C, Dorca-Arévalo J, Blasi J. Calcium enhances binding of Clostridium perfringens epsilon toxin to sulfatide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:161-169. [PMID: 30463699 DOI: 10.1016/j.bbamem.2018.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/20/2018] [Accepted: 08/07/2018] [Indexed: 01/07/2023]
Abstract
Epsilon toxin (Etx) from Clostridium perfringens is synthesized as a very low-active prototoxin form (proEtx) that becomes active upon proteolytic activation and has the capacity to cross the blood-brain barrier (BBB), thereby producing severe neurological effects. The identity and requirements of host receptors of Etx remain a matter of controversy. In the present study, we analysed the binding of proEtx or Etx to liposomes containing distearoylphosphatidylcholine (DSPC), cholesterol and sulfatide, or alternatively to detergent-solubilized lipids, using surface plasmon resonance (SPR). We also tested the influence of calcium on Etx or proEtx binding. Our findings show that the presence of sulfatide in liposomes increases both Etx and proEtx binding, and Etx binding is enhanced by calcium. These results were corroborated when SPR was conducted with immobilized toxin, since detergent-solubilized sulfatide increases its binding to Etx in the presence of calcium, but not to proEtx. Moreover, binding affinity is also affected, since the treatment of liposomes with sulfatase causes the dissociation rate constants (KD) in both proEtx and Etx to increase, especially in the case of proEtx in the presence of calcium. In addition, protein-lipid overlay assays corroborated the calcium-induced enhancement of Etx binding to sulfatide, and to lipids extracted from sulfatide-enriched rat brain lipid rafts. In conclusion, the present work highlights the role of sulfatide as an important element in the pathophysiology of Etx and reveals the influence of calcium in the interaction of Etx, but not of proEtx, with the target membrane.
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Affiliation(s)
- C Gil
- Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Catalunya, Spain.
| | - J Dorca-Arévalo
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain; Institut de Neurociències, Universitat de Barcelona, Spain
| | - J Blasi
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain; Institut de Neurociències, Universitat de Barcelona, Spain
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7
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Nagahama M, Takehara M, Miyamoto K, Ishidoh K, Kobayashi K. Acid Sphingomyelinase Promotes Cellular Internalization of Clostridium perfringens Iota-Toxin. Toxins (Basel) 2018; 10:toxins10050209. [PMID: 29783772 PMCID: PMC5983265 DOI: 10.3390/toxins10050209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 05/14/2018] [Accepted: 05/18/2018] [Indexed: 11/16/2022] Open
Abstract
Clostridium perfringens iota-toxin is a binary actin-ADP-ribosylating toxin composed of the enzymatic component Ia and receptor binding component Ib. Ib binds to a cell surface receptor, forms Ib oligomer in lipid rafts, and associates with Ia. The Ia-Ib complex then internalizes by endocytosis. Here, we showed that acid sphingomyelinase (ASMase) facilitates the cellular uptake of iota-toxin. Inhibitions of ASMase and lysosomal exocytosis by respective blockers depressed cell rounding induced by iota-toxin. The cytotoxicity of the toxin increased in the presence of Ca2+ in extracellular fluids. Ib entered target cells in the presence but not the absence of Ca2+. Ib induced the extracellular release of ASMase in the presence of Ca2+. ASMase siRNA prevented the cell rounding induced by iota-toxin. Furthermore, treatment of the cells with Ib resulted in the production of ceramide in cytoplasmic vesicles. These observations showed that ASMase promotes the internalization of iota-toxin into target cells.
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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.
| | - Kazuaki Miyamoto
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.
| | - Kazumi Ishidoh
- Division of Molecular Biology, Institute for Health Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.
| | - Keiko Kobayashi
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.
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8
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Identification and Characterization of a New Enterotoxin Produced by Clostridium perfringens Isolated from Food Poisoning Outbreaks. PLoS One 2015; 10:e0138183. [PMID: 26584048 PMCID: PMC4652906 DOI: 10.1371/journal.pone.0138183] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 08/26/2015] [Indexed: 11/25/2022] Open
Abstract
There is a strain of Clostridium perfringens, W5052, which does not produce a known enterotoxin. We herein report that the strain W5052 expressed a homologue of the iota-like toxin components sa and sb of C. spiroforme, named Clostridium perfringens iota-like enterotoxin, CPILE-a and CPILE-b, respectively, based on the results of a genome sequencing analysis and a systematic protein screening. In the nicotinamide glyco-hydrolase (NADase) assay the hydrolysis activity was dose-dependently increased by the concentration of rCPILE-a, as judged by the mass spectrometry analysis. In addition, the actin monomer of the lysates of Vero and L929 cells were radiolabeled in the presence of [32P]NAD and rCPILE-a. These findings indicated that CPILE-a possesses ADP-ribosylation activity. The culture supernatant of W5052 facilitated the rounding and killing of Vero and L929 cells, but the rCPILE-a or a non-proteolyzed rCPILE-b did not. However, a trypsin-treated rCPILE-b did. Moreover, a mixture of rCPILE-a and the trypsin-treated rCPILE-b enhanced the cell rounding and killing activities, compared with that induced by the trypsin-treated rCPILE-b alone. The injection of the mixture of rCPILE-a and the trypsin-treated rCPILE-b into an ileum loop of rabbits evoked the swelling of the loop and accumulation of the fluid dose-dependently, suggesting that CPILE possesses enterotoxic activity. The evidence presented in this communication will facilitate the epidemiological, etiological, and toxicological studies of C. perfringens food poisoning, and also stimulate studies on the transfer of the toxins’ gene(s) among the Genus Clostridium.
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9
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Stiles BG, Pradhan K, Fleming JM, Samy RP, Barth H, Popoff MR. Clostridium and bacillus binary enterotoxins: bad for the bowels, and eukaryotic being. Toxins (Basel) 2014; 6:2626-56. [PMID: 25198129 PMCID: PMC4179152 DOI: 10.3390/toxins6092626] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 08/22/2014] [Accepted: 08/27/2014] [Indexed: 12/18/2022] Open
Abstract
Some pathogenic spore-forming bacilli employ a binary protein mechanism for intoxicating the intestinal tracts of insects, animals, and humans. These Gram-positive bacteria and their toxins include Clostridium botulinum (C2 toxin), Clostridium difficile (C. difficile toxin or CDT), Clostridium perfringens (ι-toxin and binary enterotoxin, or BEC), Clostridium spiroforme (C. spiroforme toxin or CST), as well as Bacillus cereus (vegetative insecticidal protein or VIP). These gut-acting proteins form an AB complex composed of ADP-ribosyl transferase (A) and cell-binding (B) components that intoxicate cells via receptor-mediated endocytosis and endosomal trafficking. Once inside the cytosol, the A components inhibit normal cell functions by mono-ADP-ribosylation of globular actin, which induces cytoskeletal disarray and death. Important aspects of each bacterium and binary enterotoxin will be highlighted in this review, with particular focus upon the disease process involving the biochemistry and modes of action for each toxin.
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Affiliation(s)
- Bradley G Stiles
- Biology Department, Wilson College, 1015 Philadelphia Avenue, Chambersburg, PA 17201, USA.
| | - Kisha Pradhan
- Environmental Science Department, Wilson College, 1015 Philadelphia Avenue, Chambersburg, PA 17201, USA.
| | - Jodie M Fleming
- Department of Biology, North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707, USA.
| | - Ramar Perumal Samy
- Venom and Toxin Research Programme, Department of Anatomy, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Kent Ridge 117597, Singapore.
| | - Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, Ulm D-89081, Germany.
| | - Michel R Popoff
- Bacteries Anaerobies et Toxines, Institut Pasteur, 28 Rue du Docteur Roux, Paris 75724, France.
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10
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Abstract
Clostridium perfringens iota-toxin is composed of an enzymatic component (Ia) and a binding component (Ib). Ib binds to a cell surface receptor, undergoes oligomerization in lipid rafts, and binds Ia. The resulting complex is then endocytosed. Here, we show the intracellular trafficking of iota-toxin. After the binding of the Ib monomer with cells at 4°C, oligomers of Ib formed at 37°C and later disappeared. Immunofluorescence staining of Ib revealed that the internalized Ib was transported to early endosomes. Some Ib was returned to the plasma membrane through recycling endosomes, whereas the rest was transported to late endosomes and lysosomes for degradation. Degraded Ib was delivered to the plasma membrane by an increase in the intracellular Ca(2+) concentration caused by Ib. Bafilomycin A1, an endosomal acidification inhibitor, caused the accumulation of Ib in endosomes, and both nocodazole and colchicine, microtubule-disrupting agents, restricted Ib's movement in the cytosol. These results indicated that an internalized Ia and Ib complex was delivered to early endosomes and that subsequent delivery of Ia to the cytoplasm occurs mainly in early endosomes. Ib was either sent back to the plasma membranes through recycling endosomes or transported to late endosomes and lysosomes for degradation. Degraded Ib was transported to plasma membranes.
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Abstract
Clostridium perfringens iota-toxin is a binary toxin composed of an enzyme component (Ia) and a binding component (Ib). Each component alone lacks toxic activity, but together they produce cytotoxic effects. We examined the cytotoxicity of iota-toxin Ib in eight cell lines. A431 and A549 cells were susceptible to Ib, but MDCK, Vero, CHO, Caco-2, HT-29, and DLD-1 cells were not. Ib bound and formed oligomers in the membranes of A431 and MDCK cells. However, Ib entered MDCK cells but not A431 cells, suggesting that uptake is essential for cellular survival. Ib also induced cell swelling and the rapid depletion of cellular ATP in A431 and A549 cells but not the insensitive cell lines. In A431 cells, Ib binds and oligomerizes mainly in nonlipid rafts in the membranes. Disruption of lipid rafts by methyl-β-cyclodextrin did not impair ATP depletion or cell death caused by Ib. Ib induced permeabilization by propidium iodide without DNA fragmentation in A431 cells. Ultrastructural studies revealed that A431 cells undergo necrosis after treatment with Ib. Ib caused a disruption of mitochondrial permeability and the release of cytochrome c. Staining with active-form-specific antibodies showed that the proapoptotic Bcl-2-family proteins Bax and Bak were activated and colocalized with mitochondria in Ib-treated A431 cells. We demonstrate that Ib by itself produces cytotoxic activity through necrosis.
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Rich RL, Myszka DG. Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'. J Mol Recognit 2010; 23:1-64. [PMID: 20017116 DOI: 10.1002/jmr.1004] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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Clostridium perfringens iota-toxin: structure and function. Toxins (Basel) 2009; 1:208-28. [PMID: 22069542 PMCID: PMC3202787 DOI: 10.3390/toxins1020208] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 12/16/2009] [Accepted: 12/21/2009] [Indexed: 01/15/2023] Open
Abstract
Clostridium perfringens iota-toxin is composed of the enzyme component (Ia) and the binding component (Ib). Ib binds to receptor on targeted cells and translocates Ia into the cytosol of the cells. Ia ADP-ribosylates actin, resulting in cell rounding and death. Comparisons of the deduced amino acid sequence from the gene and three-dimensional structure of Ia with those of ADP-ribosylating toxins (ARTs) suggests that there is striking structural similarity among these toxins. Our objectives are to review the recent advances in the character, structure-function, and the mode of action of iota-toxin by consideration of the findings about ARTs.
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