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Alves GG, Machado de Ávila RA, Chávez-Olórtegui CD, Lobato FCF. Clostridium perfringens epsilon toxin: the third most potent bacterial toxin known. Anaerobe 2014; 30:102-7. [PMID: 25234332 DOI: 10.1016/j.anaerobe.2014.08.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/18/2014] [Accepted: 08/19/2014] [Indexed: 01/24/2023]
Abstract
Epsilon toxin (ETX) is produced by Clostridium perfringens type B and D strains and causes enterotoxemia, a highly lethal disease with major impacts on the farming of domestic ruminants, particularly sheep. ETX belongs to the aerolysin-like pore-forming toxin family. Although ETX has striking similarities to other toxins in this family, ETX is often more potent, with an LD50 of 100 ng/kg in mice. Due to this high potency, ETX is considered as a potential bioterrorism agent and has been classified as a category B biological agent by the Centers for Disease Control and Prevention (CDC) of the United States. The protoxin is converted to an active toxin through proteolytic cleavage performed by specific proteases. ETX is absorbed and acts locally in the intestines then subsequently binds to and causes lesions in other organs, including the kidneys, lungs and brain. The importance of this toxin for veterinary medicine and its possible use as a biological weapon have drawn the attention of researchers and have led to a large number of studies investigating ETX. The aim of the present work is to review the existing knowledge on ETX from C. perfringens type B and D.
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Affiliation(s)
- Guilherme Guerra Alves
- Veterinary School, Universidade Federal de Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, Belo Horizonte, MG CEP 31.270-901, Brazil.
| | | | - Carlos Delfin Chávez-Olórtegui
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, Belo Horizonte, MG CEP 31.270-901, Brazil
| | - Francisco Carlos Faria Lobato
- Veterinary School, Universidade Federal de Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, Belo Horizonte, MG CEP 31.270-901, Brazil.
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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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Garcia JP, Beingesser J, Bohorov O, Bohorova N, Goodman C, Kim D, Pauly M, Velasco J, Whaley K, Zeitlin L, Roy CJ, Uzal FA. Prevention and treatment of Clostridium perfringens epsilon toxin intoxication in mice with a neutralizing monoclonal antibody (c4D7) produced in Nicotiana benthamiana. Toxicon 2014; 88:93-8. [PMID: 24950050 PMCID: PMC4119486 DOI: 10.1016/j.toxicon.2014.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/24/2014] [Accepted: 06/10/2014] [Indexed: 11/16/2022]
Abstract
Epsilon toxin (ETX), produced by Clostridium perfringens types B and D, is among the most lethal toxins known. ETX is a potential bioterrorism threat that was listed as a Category B agent by the U.S. Centers for Disease Control until 2012 and it still remains a toxin of interest for several government agencies. We produced a monoclonal antibody (MAb) against ETX (ETX MAb c4D7) in Nicotiana benthamiana and characterized its preventive and therapeutic efficacy in mice. The ETX preparation used was highly lethal for mice (LD50 = 1.6 μg/kg) and resulted in a mean time from inoculation to death of 18 and 180 min when administered intravenously or intraperitoneally, respectively. High lethal challenge resulted in dramatic increases of a variety of pro-inflammatory cytokines in serum, while lower, but still lethal doses, did not elicit such responses. ETX MAb c4D7 was highly effective prophylactically (ED50 = 0.3 mg/kg; ED100 = 0.8 mg/kg) and also provided protection when delivered 15-30 min post-ETX intoxication. These data suggest that ETX MAb c4D7 may have use as a pre- and post-exposure treatment for ETX intoxication.
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Affiliation(s)
- J P Garcia
- California Animal Health and Food Safety Laboratory System, San Bernardino Branch, School of Veterinary Medicine, University of California, Davis, San Bernardino, CA 92408, USA
| | - J Beingesser
- California Animal Health and Food Safety Laboratory System, San Bernardino Branch, School of Veterinary Medicine, University of California, Davis, San Bernardino, CA 92408, USA
| | - O Bohorov
- Mapp Biopharmaceutical, Inc., San Diego, CA, USA
| | - N Bohorova
- Mapp Biopharmaceutical, Inc., San Diego, CA, USA
| | - C Goodman
- Mapp Biopharmaceutical, Inc., San Diego, CA, USA
| | - D Kim
- Mapp Biopharmaceutical, Inc., San Diego, CA, USA
| | - M Pauly
- Mapp Biopharmaceutical, Inc., San Diego, CA, USA
| | - J Velasco
- Mapp Biopharmaceutical, Inc., San Diego, CA, USA
| | - K Whaley
- Mapp Biopharmaceutical, Inc., San Diego, CA, USA
| | - L Zeitlin
- Mapp Biopharmaceutical, Inc., San Diego, CA, USA
| | - C J Roy
- Microbiology Division, Tulane National Primate Research Center, Covington, LA, USA
| | - F A Uzal
- California Animal Health and Food Safety Laboratory System, San Bernardino Branch, School of Veterinary Medicine, University of California, Davis, San Bernardino, CA 92408, USA.
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Dorca-Arévalo J, Pauillac S, Díaz-Hidalgo L, Martín-Satué M, Popoff MR, Blasi J. Correlation between in vitro cytotoxicity and in vivo lethal activity in mice of epsilon toxin mutants from Clostridium perfringens. PLoS One 2014; 9:e102417. [PMID: 25013927 PMCID: PMC4094505 DOI: 10.1371/journal.pone.0102417] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/19/2014] [Indexed: 12/21/2022] Open
Abstract
Epsilon toxin (Etx) from Clostridium perfringens is a pore-forming protein with a lethal effect on livestock, producing severe enterotoxemia characterized by general edema and neurological alterations. Site-specific mutations of the toxin are valuable tools to study the cellular and molecular mechanism of the toxin activity. In particular, mutants with paired cysteine substitutions that affect the membrane insertion domain behaved as dominant-negative inhibitors of toxin activity in MDCK cells. We produced similar mutants, together with a well-known non-toxic mutant (Etx-H106P), as green fluorescent protein (GFP) fusion proteins to perform in vivo studies in an acutely intoxicated mouse model. The mutant (GFP-Etx-I51C/A114C) had a lethal effect with generalized edema, and accumulated in the brain parenchyma due to its ability to cross the blood-brain barrier (BBB). In the renal system, this mutant had a cytotoxic effect on distal tubule epithelial cells. The other mutants studied (GFP-Etx-V56C/F118C and GFP-Etx-H106P) did not have a lethal effect or cross the BBB, and failed to induce a cytotoxic effect on renal epithelial cells. These data suggest a direct correlation between the lethal effect of the toxin, with its cytotoxic effect on the kidney distal tubule cells, and the ability to cross the BBB.
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Affiliation(s)
- Jonatan Dorca-Arévalo
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
- IDIBELL-Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Serge Pauillac
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, Paris, France
| | - Laura Díaz-Hidalgo
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Mireia Martín-Satué
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
- IDIBELL-Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Michel R. Popoff
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, Paris, France
| | - Juan Blasi
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
- IDIBELL-Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona, Spain
- * E-mail:
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55
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Garcia JP, Giannitti F, Finnie JW, Manavis J, Beingesser J, Adams V, Rood JI, Uzal FA. Comparative neuropathology of ovine enterotoxemia produced by Clostridium perfringens type D wild-type strain CN1020 and its genetically modified derivatives. Vet Pathol 2014; 52:465-75. [PMID: 24964921 DOI: 10.1177/0300985814540543] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Clostridium perfringens type D causes enterotoxemia in sheep and goats. The disease is mediated by epsilon toxin (ETX), which affects the cerebrovascular endothelium, increasing vascular permeability and leading to cerebral edema. In the present study, we compared the distribution and severity of the cerebrovascular changes induced in lambs by C. perfringens type D strain CN1020, its isogenic etx null mutant, and the ETX-producing complemented mutant. We also applied histochemical and immunohistochemical markers to further characterize the brain lesions induced by ETX. Both ETX-producing strains induced extensive cerebrovascular damage that did not differ significantly between each other in nature, neuroanatomic distribution, or severity. By contrast, lambs inoculated with the etx mutant or sterile, nontoxic culture medium did not develop detectable brain lesions, confirming that the neuropathologic effects observed in these infections are dependent on ETX production. Lambs treated with the wild-type and complemented strains showed perivascular and mural vascular edema, as well as serum albumin extravasation, particularly severe in the cerebral white matter, midbrain, medulla oblongata, and cerebellum. Brains of animals inoculated with the ETX-producing strains showed decreased expression of glial fibrillary acidic protein and increased expression of aquaporin-4 in the end-feet processes of the astrocytes around blood vessels. Early axonal injury was demonstrated with anti-amyloid precursor protein immunohistochemistry. Perivascular accumulation of macrophages/microglia with intracytoplasmic albumin globules was also observed in these animals. This study demonstrates that ETX is responsible for the major cerebrovascular changes in C. perfringens type D-induced disease.
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Affiliation(s)
- J P Garcia
- California Animal Health and Food Safety Laboratory System-San Bernardino Branch, School of Veterinary Medicine, University of California, Davis, San Bernardino, CA, USA These authors contributed equally to the research and are joint first authors
| | - F Giannitti
- California Animal Health and Food Safety Laboratory System-Davis Branch, School of Veterinary Medicine, University of California, Davis, Davis, CA, USA These authors contributed equally to the research and are joint first authors
| | - J W Finnie
- SA Pathology, Hanson Institute Centre for Neurological Diseases and School of Veterinary Science, University of Adelaide, Adelaide, SA, Australia
| | - J Manavis
- SA Pathology, Hanson Institute Centre for Neurological Diseases and School of Veterinary Science, University of Adelaide, Adelaide, SA, Australia
| | - J Beingesser
- California Animal Health and Food Safety Laboratory System-San Bernardino Branch, School of Veterinary Medicine, University of California, Davis, San Bernardino, CA, USA
| | - V Adams
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - J I Rood
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - F A Uzal
- California Animal Health and Food Safety Laboratory System-San Bernardino Branch, School of Veterinary Medicine, University of California, Davis, San Bernardino, CA, USA
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56
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Abstract
In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ∼45 kb to ∼140 kb. These plasmid-encoded toxins are often closely associated with mobile elements. A C. perfringens strain can carry up to three different toxin plasmids, with a single plasmid carrying up to three distinct toxin genes. Molecular Koch's postulate analyses have established the importance of several plasmid-encoded toxins when C. perfringens disease strains cause enteritis or enterotoxemias. Many toxin plasmids are closely related, suggesting a common evolutionary origin. In particular, most toxin plasmids and some antibiotic resistance plasmids of C. perfringens share an ∼35-kb region containing a Tn916-related conjugation locus named tcp (transfer of clostridial plasmids). This tcp locus can mediate highly efficient conjugative transfer of these toxin or resistance plasmids. For example, conjugative transfer of a toxin plasmid from an infecting strain to C. perfringens normal intestinal flora strains may help to amplify and prolong an infection. Therefore, the presence of toxin genes on conjugative plasmids, particularly in association with insertion sequences that may mobilize these toxin genes, likely provides C. perfringens with considerable virulence plasticity and adaptability when it causes diseases originating in the gastrointestinal tract.
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57
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Bokori-Brown M, Hall CA, Vance C, Fernandes da Costa SP, Savva CG, Naylor CE, Cole AR, Basak AK, Moss DS, Titball RW. Clostridium perfringens epsilon toxin mutant Y30A-Y196A as a recombinant vaccine candidate against enterotoxemia. Vaccine 2014; 32:2682-7. [PMID: 24709588 PMCID: PMC4022833 DOI: 10.1016/j.vaccine.2014.03.079] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/11/2014] [Accepted: 03/25/2014] [Indexed: 12/17/2022]
Abstract
Etx mutant Y30A-Y196A showed markedly reduced cytotoxicity towards MDCK.2 cells. Y30A-Y196A is inactive in mice after intraperitoneal administration. Y30A-Y196A is able to induce a specific antibody response in rabbits. Y30A-Y196A polyclonal antibody is able to induce protective immunity in vitro. Y30A-Y196A could form the basis of a recombinant vaccine against enterotoxemia.
Epsilon toxin (Etx) is a β-pore-forming toxin produced by Clostridium perfringens toxinotypes B and D and plays a key role in the pathogenesis of enterotoxemia, a severe, often fatal disease of ruminants that causes significant economic losses to the farming industry worldwide. This study aimed to determine the potential of a site-directed mutant of Etx (Y30A-Y196A) to be exploited as a recombinant vaccine against enterotoxemia. Replacement of Y30 and Y196 with alanine generated a stable variant of Etx with significantly reduced cell binding and cytotoxic activities in MDCK.2 cells relative to wild type toxin (>430-fold increase in CT50) and Y30A-Y196A was inactive in mice after intraperitoneal administration of trypsin activated toxin at 1000× the expected LD50 dose of trypsin activated wild type toxin. Moreover, polyclonal antibody raised in rabbits against Y30A-Y196A provided protection against wild type toxin in an in vitro neutralisation assay. These data suggest that Y30A-Y196A mutant could form the basis of an improved recombinant vaccine against enterotoxemia.
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Affiliation(s)
- Monika Bokori-Brown
- College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom.
| | - Charlotte A Hall
- College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Charlotte Vance
- College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Sérgio P Fernandes da Costa
- College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Christos G Savva
- Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
| | - Claire E Naylor
- Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
| | - Ambrose R Cole
- Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
| | - Ajit K Basak
- Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
| | - David S Moss
- Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
| | - Richard W Titball
- College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
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58
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Chen J, Ma M, Uzal FA, McClane BA. Host cell-induced signaling causes Clostridium perfringens to upregulate production of toxins important for intestinal infections. Gut Microbes 2014; 5:96-107. [PMID: 24061146 PMCID: PMC4049945 DOI: 10.4161/gmic.26419] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Clostridium perfringens causes enteritis and enterotoxemia in humans and livestock due to prolific toxin production. In broth culture, C. perfringens uses the Agr-like quorum sensing (QS) system to regulate production of toxins important for enteritis/enterotoxemia, including beta toxin (CPB), enterotoxin, and epsilon toxin (ETX). The VirS/VirR two-component regulatory system (TCRS) also controls CPB production in broth cultures. Both the Agr-like QS and VirS/VirR systems are important when C. perfringens senses enterocyte-like Caco-2 cells and responds by upregulating CPB production; however, only the Agr-like QS system is needed for host cell-induced ETX production. These in vitro observations have pathophysiologic relevance since both the VirS/VirR and Agr-like QS signaling systems are required for C. perfringens strain CN3685 to produce CPB in vivo and to cause enteritis or enterotoxemia. Thus, apparently upon sensing its presence in the intestines, C. perfringens utilizes QS and TCRS signaling to produce toxins necessary for intestinal virulence.
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Affiliation(s)
- Jianming Chen
- Department of Microbiology and Molecular Genetics; University of Pittsburgh School of Medicine; Pittsburgh, PA USA
| | - Menglin Ma
- Department of Microbiology and Molecular Genetics; University of Pittsburgh School of Medicine; Pittsburgh, PA USA
| | - Francisco A Uzal
- California Animal Health and Food Safety Laboratory; San Bernadino Branch, School of Veterinary Medicine; University of California Davis; San Bernadino, CA USA
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics; University of Pittsburgh School of Medicine; Pittsburgh, PA USA,Correspondence to: Bruce A McClane,
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60
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Li Q, Xin W, Gao S, Kang L, Wang J. A low-toxic site-directed mutant of Clostridium perfringens ε-toxin as a potential candidate vaccine against enterotoxemia. Hum Vaccin Immunother 2013; 9:2386-92. [PMID: 23835363 DOI: 10.4161/hv.25649] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Clostridium perfringens epsilon toxin (ETX), one of the most potent toxins known, is a potential biological weapon; therefore, the development of an effective vaccine is important for preventing intoxication or disease by ETX. In this study, genetically detoxified epsilon toxin mutants were developed as candidate vaccines. We used site-directed mutagenesis to mutate the essential amino acid residues (His106, Ser111 and Phe199). Six site-directed mutants of ETX (mETX (H106P) , mETX (S111H) , mETX (S111Y) , mETX (F199H) , mETX (F199E) , mETX (S111YF199E) ) were generated and then expressed in Escherichia coli. Both mETX (F199E) and mETX (H106P) with low or non-cytotoxicity that retained their immunogenicity were selected to immunize mice 3 times, and the mouse survival data were recorded after challenging with recombinant wild-type ETX. mETX (F199E) induces the same protection as mETX (H106P) , which was reported previously as a promising toxin mutant for vaccine, and both of them could protect immunized mice against a 100× LD₅₀ dose of active wild-type recombinant ETX. This work showed that mETX (F199E) is another promising candidate vaccine against enterotoxemia and other diseases caused by ETX.
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Affiliation(s)
- Qing Li
- Anhui Medical University; Hefei, Anhui, PR China; State Key Laboratory of Pathogen and Biosecurity; Institute of Microbiology and Epidemiology; Academy of Military Medical Sciences; Beijing, PR China
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Epsilon toxin is essential for the virulence of Clostridium perfringens type D infection in sheep, goats, and mice. Infect Immun 2013; 81:2405-14. [PMID: 23630957 DOI: 10.1128/iai.00238-13] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridium perfringens type D causes disease in sheep, goats, and other ruminants. Type D isolates produce, at minimum, alpha and epsilon (ETX) toxins, but some express up to five different toxins, raising questions about which toxins are necessary for the virulence of these bacteria. We evaluated the contribution of ETX to C. perfringens type D pathogenicity in an intraduodenal challenge model in sheep, goats, and mice using a virulent C. perfringens type D wild-type strain (WT), an isogenic ETX null mutant (etx mutant), and a strain where the etx mutation has been reversed (etx complemented). All sheep and goats, and most mice, challenged with the WT isolate developed acute clinical disease followed by death in most cases. Sheep developed various gross and/or histological changes that included edema of brain, lungs, and heart as well as hydropericardium. Goats developed various effects, including necrotizing colitis, pulmonary edema, and hydropericardium. No significant gross or histological abnormalities were observed in any mice infected with the WT strain. All sheep, goats, and mice challenged with the isogenic etx mutant remained clinically healthy for ≥24 h, and no gross or histological abnormalities were observed in those animals. Complementation of etx knockout restored virulence; most goats, sheep, and mice receiving this complemented mutant developed clinical and pathological changes similar to those observed in WT-infected animals. These results indicate that ETX is necessary for type D isolates to induce disease, supporting a key role for this toxin in type D disease pathogenesis.
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Wioland L, Dupont JL, Bossu JL, Popoff MR, Poulain B. Attack of the nervous system by Clostridium perfringens Epsilon toxin: from disease to mode of action on neural cells. Toxicon 2013; 75:122-35. [PMID: 23632158 DOI: 10.1016/j.toxicon.2013.04.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 03/29/2013] [Accepted: 04/10/2013] [Indexed: 12/24/2022]
Abstract
Epsilon toxin (ET), produced by Clostridium perfringens types B and D, ranks among the four most potent poisonous substances known so far. ET-intoxication is responsible for enterotoxaemia in animals, mainly sheep and goats. This disease comprises several manifestations indicating the attack of the nervous system. This review aims to summarize the effects of ET on central nervous system. ET binds to endothelial cells of brain capillary vessels before passing through the blood-brain barrier. Therefore, it induces perivascular oedema and accumulates into brain. ET binding to different brain structures and to different component in the brain indicates regional susceptibility to the toxin. Histological examination has revealed nerve tissue and cellular lesions, which may be directly or indirectly caused by ET. The naturally occurring disease caused by ET-intoxication can be reproduced experimentally in rodents. In mice and rats, ET recognizes receptor at the surface of different neural cell types, including certain neurons (e.g. the granule cells in cerebellum) as well as oligodendrocytes, which are the glial cells responsible for the axons myelination. Moreover, ET induces release of glutamate and other transmitters, leading to firing of neural network. The precise mode of action of ET on neural cells remains to be determined.
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Affiliation(s)
- Laetitia Wioland
- Centre National de la Recherche Scientifique (CNRS) and Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (INCI), UPR 3212, Strasbourg, France
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63
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Bokori-Brown M, Kokkinidou MC, Savva CG, Fernandes da Costa S, Naylor CE, Cole AR, Moss DS, Basak AK, Titball RW. Clostridium perfringens epsilon toxin H149A mutant as a platform for receptor binding studies. Protein Sci 2013; 22:650-9. [PMID: 23504825 PMCID: PMC3649266 DOI: 10.1002/pro.2250] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/08/2013] [Indexed: 12/24/2022]
Abstract
Clostridium perfringens epsilon toxin (Etx) is a pore-forming toxin responsible for a severe and rapidly fatal enterotoxemia of ruminants. The toxin is classified as a category B bioterrorism agent by the U.S. Government Centres for Disease Control and Prevention (CDC), making work with recombinant toxin difficult. To reduce the hazard posed by work with recombinant Etx, we have used a variant of Etx that contains a H149A mutation (Etx-H149A), previously reported to have reduced, but not abolished, toxicity. The three-dimensional structure of H149A prototoxin shows that the H149A mutation in domain III does not affect organisation of the putative receptor binding loops in domain I of the toxin. Surface exposed tyrosine residues in domain I of Etx-H149A (Y16, Y20, Y29, Y30, Y36 and Y196) were mutated to alanine and mutants Y30A and Y196A showed significantly reduced binding to MDCK.2 cells relative to Etx-H149A that correlated with their reduced cytotoxic activity. Thus, our study confirms the role of surface exposed tyrosine residues in domain I of Etx in binding to MDCK cells and the suitability of Etx-H149A for further receptor binding studies. In contrast, binding of all of the tyrosine mutants to ACHN cells was similar to that of Etx-H149A, suggesting that Etx can recognise different cell surface receptors. In support of this, the crystal structure of Etx-H149A identified a glycan (β-octyl-glucoside) binding site in domain III of Etx-H149A, which may be a second receptor binding site. These findings have important implications for developing strategies designed to neutralise toxin activity.
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Affiliation(s)
- Monika Bokori-Brown
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom.
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Affiliation(s)
| | - Sergey M. Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, U.S.A
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Oligomerization of Clostridium perfringens epsilon toxin is dependent upon caveolins 1 and 2. PLoS One 2012; 7:e46866. [PMID: 23056496 PMCID: PMC3462777 DOI: 10.1371/journal.pone.0046866] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/06/2012] [Indexed: 01/27/2023] Open
Abstract
Evidence from multiple studies suggests that Clostridium perfringens ε-toxin is a pore-forming toxin, assembling into oligomeric complexes in the plasma membrane of sensitive cells. In a previous study, we used gene-trap mutagenesis to identify mammalian factors contributing to toxin activity, including caveolin-2 (CAV2). In this study, we demonstrate the importance of caveolin-2 and its interaction partner, caveolin-1 (CAV1), in ε-toxin-induced cytotoxicity. Using CAV2-specific shRNA in a toxin-sensitive human kidney cell line, ACHN, we confirmed that cells deficient in CAV2 exhibit increased resistance to ε-toxin. Similarly, using CAV1-specific shRNA, we demonstrate that cells deficient in CAV1 also exhibit increased resistance to the toxin. Immunoprecipitation of CAV1 and CAV2 from ε-toxin-treated ACHN cells demonstrated interaction of both CAV1 and -2 with the toxin. Furthermore, blue-native PAGE indicated that the toxin and caveolins were components of a 670 kDa protein complex. Although ε-toxin binding was only slightly perturbed in caveolin-deficient cells, oligomerization of the toxin was dramatically reduced in both CAV1- and CAV2-deficient cells. These results indicate that CAV1 and -2 potentiate ε-toxin induced cytotoxicity by promoting toxin oligomerization – an event which is requisite for pore formation and, by extension, cell death.
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66
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Ivie SE, McClain MS. Identification of amino acids important for binding of Clostridium perfringens epsilon toxin to host cells and to HAVCR1. Biochemistry 2012; 51:7588-95. [PMID: 22938730 PMCID: PMC3534817 DOI: 10.1021/bi300690a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Clostridium perfringens epsilon toxin belongs to the aerolysin-like family of pore-forming toxins and is one of the most potent bacterial toxins known. The epsilon toxin causes fatal enterotoxemia in sheep, goats, and possibly humans. Evidence indicates that the toxin binds to protein receptors including hepatitis A virus cellular receptor 1 (HAVCR1), but the region of the toxin responsible for cell binding has not been identified. In the present study, we identify amino acids within the epsilon toxin important for this cell interaction. Site-specific mutagenesis was used to investigate the role of a surface-accessible cluster of aromatic amino acids, and purified mutant proteins were tested in a series of cell-culture assays to assess cytotoxic activity and cell binding. When added to cells, four mutant proteins (Etx-Y29E, Etx-Y30E, Etx-Y36E and Etx-Y196E) were severely impaired in their ability to not only kill host cells, but also in their ability to permeabilize the plasma membrane. Circular dichroism spectroscopy and thermal stability studies revealed that the wild-type and mutant proteins were similarly folded. Additional experiments revealed that these mutant proteins were defective in binding to host cells and to HAVCR1. These data indicate that an amino acid motif including Y29, Y30, Y36, and Y196 is important for the ability of epsilon toxin to interact with cells and HAVCR1.
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Affiliation(s)
- Susan E. Ivie
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Mark S. McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
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67
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Harkness JM, Li J, McClane BA. Identification of a lambda toxin-negative Clostridium perfringens strain that processes and activates epsilon prototoxin intracellularly. Anaerobe 2012; 18:546-52. [PMID: 22982043 DOI: 10.1016/j.anaerobe.2012.09.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 07/23/2012] [Accepted: 09/03/2012] [Indexed: 01/06/2023]
Abstract
Clostridium perfringens type B and D strains produce epsilon toxin (ETX), which is one of the most potent clostridial toxins and is involved in enteritis and enterotoxemias of domestic animals. ETX is produced initially as an inactive prototoxin that is typically then secreted and processed by intestinal proteases or possibly, for some strains, lambda toxin. During the current work a unique C. perfringens strain was identified that intracellularly processes epsilon prototoxin to an active form capable of killing MDCK cells. This activated toxin is not secreted but instead is apparently released upon lysis of bacterial cells entering stationary phase. These findings broaden understanding of the pathogenesis of type B and D infections by identifying a new mechanism of ETX activation.
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Affiliation(s)
- Justine M Harkness
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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68
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Seyer A, Fenaille F, Féraudet-Tarisse C, Volland H, Popoff MR, Tabet JC, Junot C, Becher F. Rapid Quantification of Clostridial Epsilon Toxin in Complex Food and Biological Matrixes by Immunopurification and Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry. Anal Chem 2012; 84:5103-9. [DOI: 10.1021/ac300880x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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69
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Dorca-Arévalo J, Martín-Satué M, Blasi J. Characterization of the high affinity binding of epsilon toxin from Clostridium perfringens to the renal system. Vet Microbiol 2012; 157:179-89. [PMID: 22264388 DOI: 10.1016/j.vetmic.2011.12.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 12/13/2011] [Accepted: 12/15/2011] [Indexed: 10/14/2022]
Abstract
Epsilon toxin (ε-toxin), produced by Clostridium perfringens types B and D, causes fatal enterotoxaemia in livestock. In the renal system, the toxin binds to target cells before oligomerization, pore formation and cell death. Still, there is little information about the cellular and molecular mechanism involved in the initial steps of the cytotoxic action of ε-toxin, including the specific binding to the target sensitive cells. In the present report, the binding step of ε-toxin to the MDCK cell line is characterized by means of an ELISA-based binding assay with recombinant ε-toxin-green fluorescence protein (ε-toxin-GFP) and ε-prototoxin-GFP. In addition, different treatments with Pronase E, detergents, N-glycosidase F and beta-elimination on MDCK cells and renal cryosections have been performed to further characterize the ε-toxin binding. The ELISA assays revealed a single binding site with a similar dissociation constant (K(d)) for ε-toxin-GFP and ε-prototoxin-GFP, but a three-fold increase in B(max) levels in the case of ε-toxin-GFP. Double staining on kidney cryoslices with lectins and ε-prototoxin-GFP revealed specific binding to distal and collecting tubule cells. In addition, experiments on kidney and bladder cryoslices demonstrated the specific binding to distal tubule of a range of mammalian renal systems. Pronase E and beta-elimination treatments on kidney cryoslices and MDCK cells revealed that the binding of ε-toxin in renal system is mediated by a O-glycoprotein. Detergent treatments revealed that the integrity of the plasma membrane is required for the binding of ε-toxin to its receptor.
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Affiliation(s)
- Jonatan Dorca-Arévalo
- Department of Pathology and Experimental Therapeutics, School of Medicine, Campus of Bellvitge, Health Universitat de Barcelona Campus (HUBc), University of Barcelona, c/Feixa Llarga s/n 08907, L'Hospitalet de Llobregat, Spain
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70
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Epsilon-toxin production by Clostridium perfringens type D strain CN3718 is dependent upon the agr operon but not the VirS/VirR two-component regulatory system. mBio 2011; 2:mBio.00275-11. [PMID: 22167225 PMCID: PMC3236063 DOI: 10.1128/mbio.00275-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridium perfringens type B and D strains cause enterotoxemias and enteritis in livestock after proliferating in the intestines and producing epsilon-toxin (ETX), alpha-toxin (CPA), and, usually, perfringolysin O (PFO). Although ETX is one of the most potent bacterial toxins, the regulation of ETX production by type B or D strains remains poorly understood. The present work determined that the type D strain CN3718 upregulates production of ETX upon close contact with enterocyte-like Caco-2 cells. This host cell-induced upregulation of ETX expression was mediated at the transcriptional level. Using an isogenic agrB null mutant and complemented strain, the agr operon was shown to be required when CN3718 produces ETX in broth culture or, via a secreted signal consistent with a quorum-sensing (QS) effect, upregulates ETX production upon contact with host cells. These findings provide the first insights into the regulation of ETX production, as well as additional evidence that the Agr-like QS system functions as a global regulator of C. perfringens toxin production. Since it was proposed previously that the Agr-like QS system regulates C. perfringens gene expression via the VirS/VirR two-component regulatory system, an isogenic virR null mutant of CN3718 was constructed to evaluate the importance of VirS/VirR for CN3718 toxin production. This mutation affected production of CPA and PFO, but not ETX, by CN3718. These results provide the first indication that C. perfringens toxin expression regulation by the Agr-like quorum-sensing system may not always act via the VirS/VirR two-component system. IMPORTANCE Mechanisms by which Clostridium perfringens type B and D strains regulate production of epsilon-toxin (ETX), a CDC class B select toxin, are poorly understood. Production of several other toxins expressed by C. perfringens is wholly or partially regulated by both the Agr-like quorum-sensing (QS) system and the VirS/VirR two-component regulatory system, so the present study tested whether ETX expression by type D strain CN3718 also requires these regulatory systems. The agr operon was shown to be essential for signaling CN3718 to produce ETX in broth culture or to upregulate ETX production upon close contact with enterocyte-like Caco-2 cells, which may have pathogenic relevance since ETX is produced intestinally. However, ETX production remained at wild-type levels after inactivation of the VirS/VirR system in CN3718. These findings provide the first information regarding regulation of ETX production and suggest Agr-like QS toxin production regulation in C. perfringens does not always require the VirS/VirR system.
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71
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Morris WE, Dunleavy MV, Diodati J, Berra G, Fernandez-Miyakawa ME. Effects of Clostridium perfringens alpha and epsilon toxins in the bovine gut. Anaerobe 2011; 18:143-7. [PMID: 22178571 DOI: 10.1016/j.anaerobe.2011.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 09/10/2011] [Accepted: 12/06/2011] [Indexed: 11/15/2022]
Abstract
Clostridium perfringens alpha and epsilon toxins produce enterotoxaemia in sheep and goats. However, the information regarding the pathophysiology of alpha and epsilon toxins in the bovine intestine is still scanty. In this study, intestinal loops were performed in the ileum and colon of three one-week-old Holstein and two four-week-old crossbreed calves. Laparotomy was performed in all calves under anaesthesia and four loops -three cm long- were performed in the small and large intestines. For both intestines, loops were inoculated with alpha or epsilon toxins. Tissue samples from all loops were obtained and processed for routine histology and for transmission electron microscopy. Congestion was observed in toxin treated loops. Fluid accumulation in the gut lumen was prominent in all treated loops, but in epsilon treated ones the mucous was also haemorrhagic. The histology revealed large amount of exfoliated epithelial cells in the lumen of alpha toxin treated loops and severe haemorrhage was observed in the lamina propria of epsilon toxin treated colonic loops. Despite some necrotic exfoliated enterocytes, no ultraestructural changes were observed in alpha toxin treated loops, though with epsilon toxin the loops exhibited dilation of the intercellular space in the mucosa of both, small and large intestines. These observations indicate that both, alpha and epsilon toxins can alter the intestinal barrier, in calves and are pathogenic for this species.
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Affiliation(s)
- Winston E Morris
- Veterinary and Agronomic Research Centre (CICVyA), National Institute of Agricultural Technology (INTA), Castelar, Buenos Aires, Argentina.
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72
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Popoff MR. Multifaceted interactions of bacterial toxins with the gastrointestinal mucosa. Future Microbiol 2011; 6:763-97. [PMID: 21797691 DOI: 10.2217/fmb.11.58] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The digestive tract is one of the ecosystems that harbors the largest number and greatest variety of bacteria. Among them, certain bacteria have developed various strategies, including the synthesis of virulence factors such as toxins, to interact with the intestinal mucosa, and are responsible for various pathologies. A large variety of bacterial toxins of different sizes, structures and modes of action are able to interact with the gastrointestinal mucosa. Some toxins, termed enterotoxins, directly stimulate fluid secretion in enterocytes or cause their death, whereas other toxins pass through the intestinal barrier and disseminate by the general circulation to remote organs or tissues, where they are active. After recognition of a membrane receptor on target cells, toxins can act at the cell membrane by transducing a signal across the membrane in a hormone-like manner, by pore formation or by damaging membrane compounds. Other toxins can enter the cells and modify an intracellular target leading to a disregulation of certain physiological processes or disorganization of some structural architectures and cell death. Toxins are fascinating molecules, which mimic or interfere with eukaryotic physiological processes. Thereby, they have permitted the identification and characterization of new natural hormones or regulatory pathways. Besides use as protective antigens in vaccines, toxins offer multiple possibilities in pharmacology, such as immune modulation or specific delivery of a protein of interest into target cells.
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Affiliation(s)
- M R Popoff
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, 25 rue du Dr Roux, 757245 Paris cedex 15, France.
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73
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Nagahama M, Itohayashi Y, Hara H, Higashihara M, Fukatani Y, Takagishi T, Oda M, Kobayashi K, Nakagawa I, Sakurai J. Cellular vacuolation induced by Clostridium perfringens epsilon-toxin. FEBS J 2011; 278:3395-407. [PMID: 21781280 DOI: 10.1111/j.1742-4658.2011.08263.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The epsilon-toxin of Clostridium perfringens forms a heptamer in the membranes of Madin-Darby canine kidney cells, leading to cell death. Here, we report that it caused the vacuolation of Madin-Darby canine kidney cells. The toxin induced vacuolation in a dose-dependent and time-dependent manner. The monomer of the toxin formed oligomers on lipid rafts in membranes of the cells. Methyl-β-cyclodextrin and poly(ethylene glycol) 4000 inhibited the vacuolation. Epsilon-toxin was internalized into the cells. Confocal microscopy revealed that the internalized toxin was transported from early endosomes (early endosome antigen 1 staining) to late endosomes and lysosomes (lysosomal-associated membrane protein 2 staining) and then distributed to the membranes of vacuoles. Furthermore, the vacuolation was inhibited by bafilomycin A1, a V-type ATPase inhibitor, and colchicine and nocodazole, microtubule-depolymerizing agents. The early endosomal marker green fluorescent protein-Rab5 and early endosome antigen 1 did not localize to vacuolar membranes. In contrast, the vacuolar membranes were specifically stained by the late endosomal and lysosomal marker green fluorescent protein-Rab7 and lysosomal-associated membrane protein 2. The vacuoles in the toxin-treated cells were stained with LysoTracker Red DND-99, a marker for late endosomes and lysosomes. A dominant negative mutant of Rab7 prevented the vacuolization, whereas a mutant form of Rab5 was less effective. These results demonstrate, for the first time, that: (a) oligomers of epsilon-toxin formed in lipid rafts are endocytosed; and (b) the vacuoles originating from late endosomes and lysosomes are formed by an oligomer of epsilon-toxin.
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Affiliation(s)
- Masahiro Nagahama
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan.
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74
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Robertson SL, Li J, Uzal FA, McClane BA. Evidence for a prepore stage in the action of Clostridium perfringens epsilon toxin. PLoS One 2011; 6:e22053. [PMID: 21814565 PMCID: PMC3140917 DOI: 10.1371/journal.pone.0022053] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Accepted: 06/16/2011] [Indexed: 11/25/2022] Open
Abstract
Clostridium perfringens epsilon toxin (ETX) rapidly kills MDCK II cells at 37°C, but not 4°C. The current study shows that, in MDCK II cells, ETX binds and forms an oligomeric complex equally well at 37°C and 4°C but only forms a pore at 37°C. However, the complex formed in MDCK cells treated with ETX at 4°C has the potential to form an active pore, since shifting those cells to 37°C results in rapid cytotoxicity. Those results suggested that the block in pore formation at 4°C involves temperature-related trapping of ETX in a prepore intermediate on the MDCK II cell plasma membrane surface. Evidence supporting this hypothesis was obtained when the ETX complex in MDCK II cells was shown to be more susceptible to pronase degradation when formed at 4°C vs. 37°C; this result is consistent with ETX complex formed at 4°C remaining present in an exposed prepore on the membrane surface, while the ETX prepore complex formed at 37°C is unaccessible to pronase because it has inserted into the plasma membrane to form an active pore. In addition, the ETX complex rapidly dissociated from MDCK II cells at 4°C, but not 37°C; this result is consistent with the ETX complex being resistant to dissociation at 37°C because it has inserted into membranes, while the ETX prepore readily dissociates from cells at 4°C because it remains on the membrane surface. These results support the identification of a prepore stage in ETX action and suggest a revised model for ETX cytotoxicity, i) ETX binds to an unidentified receptor, ii) ETX oligomerizes into a prepore on the membrane surface, and iii) the prepore inserts into membranes, in a temperature-sensitive manner, to form an active pore.
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Affiliation(s)
- Susan L. Robertson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jihong Li
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Francisco A. Uzal
- California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Bruce A. McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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75
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Zhao Y, Kang L, Gao S, Zhou Y, Su L, Xin W, Su Y, Wang J. Expression and purification of functional Clostridium perfringens alpha and epsilon toxins in Escherichia coli. Protein Expr Purif 2011; 77:207-13. [DOI: 10.1016/j.pep.2011.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 01/13/2011] [Accepted: 02/01/2011] [Indexed: 11/30/2022]
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77
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Bokori-Brown M, Savva CG, Fernandes da Costa SP, Naylor CE, Basak AK, Titball RW. Molecular basis of toxicity of Clostridium perfringens epsilon toxin. FEBS J 2011; 278:4589-601. [PMID: 21518257 DOI: 10.1111/j.1742-4658.2011.08140.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Clostridium perfringens ε-toxin is produced by toxinotypes B and D strains. The toxin is the aetiological agent of dysentery in newborn lambs but is also associated with enteritis and enterotoxaemia in goats, calves and foals. It is considered to be a potential biowarfare or bioterrorism agent by the US Government Centers for Disease Control and Prevention. The relatively inactive 32.9 kDa prototoxin is converted to active mature toxin by proteolytic cleavage, either by digestive proteases of the host, such as trypsin and chymotrypsin, or by C. perfringens λ-protease. In vivo, the toxin appears to target the brain and kidneys, but relatively few cell lines are susceptible to the toxin, and most work has been carried out using Madin-Darby canine kidney (MDCK) cells. The binding of ε-toxin to MDCK cells and rat synaptosomal membranes is associated with the formation of a stable, high molecular weight complex. The crystal structure of ε-toxin reveals similarity to aerolysin from Aeromonas hydrophila, parasporin-2 from Bacillus thuringiensis and a lectin from Laetiporus sulphureus. Like these toxins, ε-toxin appears to form heptameric pores in target cell membranes. The exquisite specificity of the toxin for specific cell types suggests that it binds to a receptor found only on these cells.
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Affiliation(s)
- Monika Bokori-Brown
- Biosciences, College of Life and Environmental Sciences, University of Exeter, UK
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78
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Ivie SE, Fennessey CM, Sheng J, Rubin DH, McClain MS. Gene-trap mutagenesis identifies mammalian genes contributing to intoxication by Clostridium perfringens ε-toxin. PLoS One 2011; 6:e17787. [PMID: 21412435 PMCID: PMC3055893 DOI: 10.1371/journal.pone.0017787] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 02/14/2011] [Indexed: 12/13/2022] Open
Abstract
The Clostridium perfringens ε-toxin is an extremely potent toxin associated with lethal toxemias in domesticated ruminants and may be toxic to humans. Intoxication results in fluid accumulation in various tissues, most notably in the brain and kidneys. Previous studies suggest that the toxin is a pore-forming toxin, leading to dysregulated ion homeostasis and ultimately cell death. However, mammalian host factors that likely contribute to ε-toxin-induced cytotoxicity are poorly understood. A library of insertional mutant Madin Darby canine kidney (MDCK) cells, which are highly susceptible to the lethal affects of ε-toxin, was used to select clones of cells resistant to ε-toxin-induced cytotoxicity. The genes mutated in 9 surviving resistant cell clones were identified. We focused additional experiments on one of the identified genes as a means of validating the experimental approach. Gene expression microarray analysis revealed that one of the identified genes, hepatitis A virus cellular receptor 1 (HAVCR1, KIM-1, TIM1), is more abundantly expressed in human kidney cell lines than it is expressed in human cells known to be resistant to ε-toxin. One human kidney cell line, ACHN, was found to be sensitive to the toxin and expresses a larger isoform of the HAVCR1 protein than the HAVCR1 protein expressed by other, toxin-resistant human kidney cell lines. RNA interference studies in MDCK and in ACHN cells confirmed that HAVCR1 contributes to ε-toxin-induced cytotoxicity. Additionally, ε-toxin was shown to bind to HAVCR1 in vitro. The results of this study indicate that HAVCR1 and the other genes identified through the use of gene-trap mutagenesis and RNA interference strategies represent important targets for investigation of the process by which ε-toxin induces cell death and new targets for potential therapeutic intervention.
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Affiliation(s)
- Susan E. Ivie
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Christine M. Fennessey
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Jinsong Sheng
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Donald H. Rubin
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Research Medicine, VA Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Mark S. McClain
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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Polymer partitioning and ion selectivity suggest asymmetrical shape for the membrane pore formed by epsilon toxin. Biophys J 2010; 99:782-9. [PMID: 20682255 DOI: 10.1016/j.bpj.2010.05.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 04/27/2010] [Accepted: 05/03/2010] [Indexed: 12/25/2022] Open
Abstract
Using poly-(ethylene glycol)s of different molecular weights, we probe the channels formed in planar lipid bilayers by epsilon toxin secreted by the anaerobic bacterium Clostridium perfringens. We find that the pore is highly asymmetric. The cutoff size of polymers entering the pore through its opening from the cis side, the side of toxin addition, is approximately 500 Da, whereas the cutoff size for the polymers entering from the trans side is approximately 2300 Da. Comparing these characteristic molecular weights with those reported earlier for OmpF porin and the alpha-Hemolysin channel, we estimate the radii of cis and trans openings as 0.4 nm and 1.0 nm, respectively. The simplest geometry corresponding to these findings is that of a truncated cone. The asymmetry of the pore is also confirmed by measurements of the reversal potential at oppositely directed salt gradients. The moderate anionic selectivity of the channel is salted-out more efficiently when the salt concentration is higher at the trans side of the pore.
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80
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Lewis M, Weaver CD, McClain MS. Identification of Small Molecule Inhibitors of Clostridium perfringens ε-Toxin Cytotoxicity Using a Cell-Based High-Throughput Screen. Toxins (Basel) 2010; 2:1825-1847. [PMID: 20721308 PMCID: PMC2922765 DOI: 10.3390/toxins2071825] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The Clostridium perfringens epsilon toxin, a select agent, is responsible for a severe, often fatal enterotoxemia characterized by edema in the heart, lungs, kidney, and brain. The toxin is believed to be an oligomeric pore-forming toxin. Currently, there is no effective therapy for countering the cytotoxic activity of the toxin in exposed individuals. Using a robust cell-based high-throughput screening (HTS) assay, we screened a 151,616-compound library for the ability to inhibit ε-toxin-induced cytotoxicity. Survival of MDCK cells exposed to the toxin was assessed by addition of resazurin to detect metabolic activity in surviving cells. The hit rate for this screen was 0.6%. Following a secondary screen of each hit in triplicate and assays to eliminate false positives, we focused on three structurally-distinct compounds: an N-cycloalkylbenzamide, a furo[2,3-b]quinoline, and a 6H-anthra[1,9-cd]isoxazol. None of the three compounds appeared to inhibit toxin binding to cells or the ability of the toxin to form oligomeric complexes. Additional assays demonstrated that two of the inhibitory compounds inhibited ε-toxin-induced permeabilization of MDCK cells to propidium iodide. Furthermore, the two compounds exhibited inhibitory effects on cells pre-treated with toxin. Structural analogs of one of the inhibitors identified through the high-throughput screen were analyzed and provided initial structure-activity data. These compounds should serve as the basis for further structure-activity refinement that may lead to the development of effective anti-ε-toxin therapeutics.
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Affiliation(s)
- Michelle Lewis
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA;
| | - Charles David Weaver
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA;
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37235, USA;
| | - Mark S. McClain
- Department of Medicine, Vanderbilt University, Nashville, TN 37235, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-615-322-2035; Fax: +1-615-343-6160
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81
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Souza AM, Reis JKP, Assis RA, Horta CC, Siqueira FF, Facchin S, Alvarenga ER, Castro CS, Salvarani FM, Silva ROS, Pires PS, Contigli C, Lobato FCF, Kalapothakis E. Molecular cloning and expression of epsilon toxin from Clostridium perfringens type D and tests of animal immunization. GENETICS AND MOLECULAR RESEARCH 2010; 9:266-76. [PMID: 20198582 DOI: 10.4238/vol9-1gmr711] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Epsilon toxin produced by Clostridium perfringens types B and D causes enterotoxemia in sheep, goats and calves. Enterotoxemia can cause acute or superacute disease, with sudden death of the affected animal. It provokes huge economic losses when large numbers of livestock are affected. Therapeutic intervention is challenging, because the disease progresses very rapidly. However, it can be prevented by immunization with specific immunogenic vaccines. We cloned the etx gene, encoding epsilon toxin, into vector pET-11a; recombinant epsilon toxin (rec-epsilon) was expressed in inclusion bodies and was used for animal immunization. Serum protection was evaluated and cross-serum neutralization tests were used to characterize the recombinant toxin. To analyze the potency of the toxin (as an antigen), rabbits were immunized with 50, 100 or 200 microg recombinant toxin, using aluminum hydroxide gel as an adjuvant. Titers of 10, 30 and 40 IU/mL were obtained, respectively. These titers were higher than the minimum level required by the European Pharmacopoeia (5 IU/mL) and by the USA Code of Federal Regulation (2 IU/mL). This rec-epsilon is a good candidate for vaccine production against enterotoxemia caused by epsilon toxin of C. perfringens type D.
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Affiliation(s)
- A M Souza
- Laboratório de Marcadores Moleculares e Biotecnologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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82
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Abstract
Clostridia produce the highest number of toxins of any type of bacteria and are involved in severe diseases in humans and other animals. Most of the clostridial toxins are pore-forming toxins responsible for gangrenes and gastrointestinal diseases. Among them, perfringolysin has been extensively studied and it is the paradigm of the cholesterol-dependent cytolysins, whereas Clostridium perfringens epsilon-toxin and Clostridium septicum alpha-toxin, which are related to aerolysin, are the prototypes of clostridial toxins that form small pores. Other toxins active on the cell surface possess an enzymatic activity, such as phospholipase C and collagenase, and are involved in the degradation of specific cell-membrane or extracellular-matrix components. Three groups of clostridial toxins have the ability to enter cells: large clostridial glucosylating toxins, binary toxins and neurotoxins. The binary and large clostridial glucosylating toxins alter the actin cytoskeleton by enzymatically modifying the actin monomers and the regulatory proteins from the Rho family, respectively. Clostridial neurotoxins proteolyse key components of neuroexocytosis. Botulinum neurotoxins inhibit neurotransmission at neuromuscular junctions, whereas tetanus toxin targets the inhibitory interneurons of the CNS. The high potency of clostridial toxins results from their specific targets, which have an essential cellular function, and from the type of modification that they induce. In addition, clostridial toxins are useful pharmacological and biological tools.
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Affiliation(s)
- Michel R Popoff
- Institut Pasteur, Bactéries Anaérobies et Toxines, 75724 Paris cedex 15, France.
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83
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Characterization of virulence plasmid diversity among Clostridium perfringens type B isolates. Infect Immun 2009; 78:495-504. [PMID: 19858300 DOI: 10.1128/iai.00838-09] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The important veterinary pathogen Clostridium perfringens type B is unique for producing the two most lethal C. perfringens toxins, i.e., epsilon-toxin and beta-toxin. Our recent study (K. Miyamoto, J. Li, S. Sayeed, S. Akimoto, and B. A. McClane, J. Bacteriol. 190:7178-7188, 2008) showed that most, if not all, type B isolates carry a 65-kb epsilon-toxin-encoding plasmid. However, this epsilon-toxin plasmid did not possess the cpb gene encoding beta-toxin, suggesting that type B isolates carry at least one additional virulence plasmid. Therefore, the current study used Southern blotting of pulsed-field gels to localize the cpb gene to approximately 90-kb plasmids in most type B isolates, although a few isolates carried a approximately 65-kb cpb plasmid distinct from their etx plasmid. Overlapping PCR analysis then showed that the gene encoding the recently discovered TpeL toxin is located approximately 3 kb downstream of the plasmid-borne cpb gene. As shown earlier for their epsilon-toxin-encoding plasmids, the beta-toxin-encoding plasmids of type B isolates were found to carry a tcp locus, suggesting that they are conjugative. Additionally, IS1151-like sequences were identified upstream of the cpb gene in type B isolates. These IS1151-like sequences may mobilize the cpb gene based upon detection of possible cpb-containing circular transposition intermediates. Most type B isolates also possessed a third virulence plasmid that carries genes encoding urease and lambda-toxin. Collectively, these findings suggest that type B isolates are among the most plasmid dependent of all C. perfringens isolates for virulence, as they usually carry three potential virulence plasmids.
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84
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Pelish TM, McClain MS. Dominant-negative inhibitors of the Clostridium perfringens epsilon-toxin. J Biol Chem 2009; 284:29446-53. [PMID: 19720828 PMCID: PMC2785577 DOI: 10.1074/jbc.m109.021782] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 08/24/2009] [Indexed: 01/27/2023] Open
Abstract
The Clostridium perfringens epsilon-toxin is responsible for a severe, often lethal intoxication. In this study, we characterized dominant-negative inhibitors of the epsilon-toxin. Site-specific mutations were introduced into the gene encoding epsilon-toxin, and recombinant proteins were expressed in Escherichia coli. Paired cysteine substitutions were introduced at locations predicted to form a disulfide bond. One cysteine in each mutant was introduced into the membrane insertion domain of the toxin; the second cysteine was introduced into the protein backbone. Mutant proteins with cysteine substitutions at amino acid positions I51/A114 and at V56/F118 lacked detectable cytotoxic activity in a MDCK cell assay. Cytotoxic activity could be reconstituted in both mutant proteins by incubation with dithiothreitol, indicating that the lack of cytotoxic activity was attributable to the formation of a disulfide bond. Fluorescent labeling of the cysteines also indicated that the introduced cysteines participated in a disulfide bond. When equimolar mixtures of wild-type epsilon-toxin and mutant proteins were added to MDCK cells, the I51C/A114C and V56C/F118C mutant proteins each inhibited the activity of wild-type epsilon-toxin. Further analysis of the inhibitory activity of the I51C/A114C and V56C/F118C mutant proteins indicated that these proteins inhibit the ability of the active toxin to form stable oligomeric complexes in the context of MDCK cells. These results provide further insight into the properties of dominant-negative inhibitors of oligomeric pore-forming toxins and provide the basis for developing new therapeutics for treating intoxication by epsilon-toxin.
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Affiliation(s)
- Teal M. Pelish
- From the Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Mark S. McClain
- From the Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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85
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Knapp O, Maier E, Benz R, Geny B, Popoff MR. Identification of the channel-forming domain of Clostridium perfringens Epsilon-toxin (ETX). BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2584-93. [PMID: 19835840 DOI: 10.1016/j.bbamem.2009.09.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 09/17/2009] [Accepted: 09/29/2009] [Indexed: 10/20/2022]
Abstract
Epsilon-toxin (ETX) is a potent toxin produced by Clostridium perfringens strains B and D. The bacteria are important pathogens in domestic animals and cause edema mediated by ETX. This toxin acts most likely by heptamer formation and rapid permeabilization of target cell membranes for monovalent anions and cations followed by a later entry of calcium. In this study, we compared the primary structure of ETX with that of the channel-forming stretches of a variety of binding components of A-B-types of toxins such as Anthrax protective antigen (PA), C2II of C2-toxin and Ib of Iota-toxin and found a remarkable homology to amino acids 151-180 of ETX. Site-directed mutagenesis of amino acids within the putative channel-forming domain resulted in changes of cytotoxicity and effects on channel characteristics in lipid bilayer experiments including changes of selectivity and partial channel block by methanethiosulfonate (MTS) reagents and antibodies against His(6)-tags from the trans-side of the lipid bilayer membranes.
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Affiliation(s)
- Oliver Knapp
- Department of Biotechnology, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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86
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Goldstein J, Morris WE, Loidl CF, Tironi-Farinatti C, McClane BA, Uzal FA, Fernandez Miyakawa ME. Clostridium perfringens epsilon toxin increases the small intestinal permeability in mice and rats. PLoS One 2009; 4:e7065. [PMID: 19763257 PMCID: PMC2739291 DOI: 10.1371/journal.pone.0007065] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 08/13/2009] [Indexed: 11/29/2022] Open
Abstract
Epsilon toxin is a potent neurotoxin produced by Clostridium perfringens types B and D, an anaerobic bacterium that causes enterotoxaemia in ruminants. In the affected animal, it causes oedema of the lungs and brain by damaging the endothelial cells, inducing physiological and morphological changes. Although it is believed to compromise the intestinal barrier, thus entering the gut vasculature, little is known about the mechanism underlying this process. This study characterizes the effects of epsilon toxin on fluid transport and bioelectrical parameters in the small intestine of mice and rats. The enteropooling and the intestinal loop tests, together with the single-pass perfusion assay and in vitro and ex vivo analysis in Ussing's chamber, were all used in combination with histological and ultrastructural analysis of mice and rat small intestine, challenged with or without C. perfringens epsilon toxin. Luminal epsilon toxin induced a time and concentration dependent intestinal fluid accumulation and fall of the transepithelial resistance. Although no evident histological changes were observed, opening of the mucosa tight junction in combination with apoptotic changes in the lamina propria were seen with transmission electron microscopy. These results indicate that C. perfringens epsilon toxin alters the intestinal permeability, predominantly by opening the mucosa tight junction, increasing its permeability to macromolecules, and inducing further degenerative changes in the lamina propria of the bowel.
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Affiliation(s)
- Jorge Goldstein
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Winston E. Morris
- Instituto de Patobiología, Centro Nacional de Investigaciones Agropecuarias, Instituto Nacional de Tecnología Agropecuaria, Castelar, Buenos Aires, Argentina
| | - César Fabián Loidl
- Instituto de Biología Celular y Neurociencia “Prof. E. De Robertis”, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Carla Tironi-Farinatti
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Bruce A. McClane
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Francisco A. Uzal
- California Animal Health and Food Safety Laboratory System, San Bernardino Branch, School of Veterinary Medicine, University of California Davis, San Bernardino, California, United States of America
| | - Mariano E. Fernandez Miyakawa
- Instituto de Patobiología, Centro Nacional de Investigaciones Agropecuarias, Instituto Nacional de Tecnología Agropecuaria, Castelar, Buenos Aires, Argentina
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87
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Knapp O, Maier E, Mkaddem SB, Benz R, Bens M, Chenal A, Geny B, Vandewalle A, Popoff MR. Clostridium septicum alpha-toxin forms pores and induces rapid cell necrosis. Toxicon 2009; 55:61-72. [PMID: 19632260 DOI: 10.1016/j.toxicon.2009.06.037] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 06/25/2009] [Accepted: 06/29/2009] [Indexed: 11/25/2022]
Abstract
Alpha-toxin is the unique lethal virulent factor produced by Clostridium septicum, which causes traumatic or non-traumatic gas gangrene and necrotizing enterocolitis in humans. Here, we analyzed channel formation of the recombinant septicum alpha-toxin and characterized its activity on living cells. Recombinant septicum alpha-toxin induces the formation of ion-permeable channels with a single-channel conductance of about 175pS in 0.1M KCl in lipid bilayer membranes, which is typical for a large diffusion pore. Septicum alpha-toxin channels remained mostly in the open configuration, displayed no lipid specificity, and exhibited slight anion selectivity. Septicum alpha-toxin caused a rapid decrease in the transepithelial electrical resistance of MDCK cell monolayers grown on filters, and induced a rapid cell necrosis in a variety of cell lines, characterized by cell permeabilization to propidium iodide without DNA fragmentation and activation of caspase-3. Septicum alpha-toxin also induced a rapid K(+) efflux and ATP depletion. Incubation of the cells in K(+)-enriched medium delayed cell death caused by septicum alpha-toxin or epsilon-toxin, another potent pore-forming toxin, suggesting that the rapid loss of intracellular K(+) represents an early signal of pore-forming toxins-mediated cell necrosis.
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Affiliation(s)
- Oliver Knapp
- Institut Pasteur, Bactéries anaérobies et Toxines, 28 rue du Dr Roux, F-75724 Paris cedex 15, France
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88
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Uzal FA, Songer JG. Diagnosis of Clostridium perfringens intestinal infections in sheep and goats. J Vet Diagn Invest 2008; 20:253-65. [PMID: 18460610 DOI: 10.1177/104063870802000301] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Clostridium perfringens produces enteric diseases, generically called enterotoxemias, in sheep, goats, and other animals. This microorganism can be a normal inhabitant of the intestine of most animal species, including humans, but when the intestinal environment is altered by sudden changes in diet or other factors, C. perfringens proliferates and produces potent toxins that act locally or are absorbed into the general circulation with usually devastating effects on the host. History, clinical signs, and gross postmortem findings are useful tools for establishing a presumptive diagnosis of clostridial enterotoxemia in sheep and goats. Definitive diagnosis requires laboratory confirmation. Isolation of some types of C. perfringens (e.g., B and C) can be of diagnostic value, but other types (e.g., A) are so commonly found in the intestine of normal animals that isolation is meaningless from a diagnostic point of view. The most accepted criterion in establishing a definitive diagnosis of enterotoxemia is detection of C. perfringens toxins in intestinal contents. Also, histopathological examination of brain is very useful for diagnosis of type D disease, as lesions produced by epsilon toxin in the brains of sheep and goats are pathognomonic for type D enterotoxemia. Ancillary tests, such as measuring urine glucose or observing Gram-stained smears of intestinal mucosa, can be used. However, although such tests have a presumptive diagnostic value when positive, they cannot be used to rule out a diagnosis of enterotoxemia when negative.
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Affiliation(s)
- Francisco A Uzal
- California Animal Health and Food Safety Laboratory System, University of California, Davis, San Bernardino, CA 92408, USA.
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89
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Nickerson NN, Joag V, McGavin MJ. Rapid autocatalytic activation of the M4 metalloprotease aureolysin is controlled by a conserved N-terminal fungalysin-thermolysin-propeptide domain. Mol Microbiol 2008; 69:1530-43. [DOI: 10.1111/j.1365-2958.2008.06384.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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90
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Binding of epsilon-toxin from Clostridium perfringens in the nervous system. Vet Microbiol 2008; 131:14-25. [PMID: 18406080 DOI: 10.1016/j.vetmic.2008.02.015] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 02/18/2008] [Accepted: 02/20/2008] [Indexed: 11/20/2022]
Abstract
Epsilon-toxin (epsilon-toxin), produced by Clostridium perfringens type D, is the main agent responsible for enterotoxaemia in livestock. Neurological disorders are a characteristic of the onset of toxin poisoning. Epsilon-Toxin accumulates specifically in the central nervous system, where it produces a glutamatergic-mediated excitotoxic effect. However, no detailed study of putative binding structures in the nervous tissue has been carried out to date. Here we attempt to identify specific acceptor moieties and cell targets for epsilon-toxin, not only in the mouse nervous system but also in the brains of sheep and cattle. An epsilon-toxin-GFP fusion protein was produced and used to incubate brain sections, which were then analyzed by confocal microscopy. The results clearly show specific binding of epsilon-toxin to myelin structures. epsilon-Prototoxin-GFP and epsilon-toxin-GFP, the inactive and active forms of the toxin, respectively, showed identical results. By means of pronase E treatment, we found that the binding was mainly associated to a protein component of the myelin. Myelinated peripheral nerve fibres were also stained by epsilon-toxin. Moreover, the binding to myelin was not only restricted to rodents, but was also found in humans, sheep and cattle. Curiously, in the brains of both sheep and cattle, the toxin strongly stained the vascular endothelium, a result that may explain the differences in potency and effect between species. Although the binding of epsilon-toxin to myelin does not directly explain its neurotoxic effect, this feature opens up a new line of enquiry into its mechanism of toxicity and establishes the usefulness of this toxin for the study of the mammalian nervous system.
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91
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Losada-Eaton DM, Uzal FA, Fernández Miyakawa ME. Clostridium perfringens epsilon toxin is absorbed from different intestinal segments of mice. Toxicon 2008; 51:1207-13. [PMID: 18457853 DOI: 10.1016/j.toxicon.2008.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2007] [Revised: 02/07/2008] [Accepted: 02/08/2008] [Indexed: 11/30/2022]
Abstract
Clostridium perfringens epsilon toxin is a potent toxin responsible for a rapidly fatal enterotoxaemia in several animal species. The pathogenesis of epsilon toxin includes toxicity to endothelial cells and neurons. Although epsilon toxin is absorbed from the gastrointestinal tract, the intestinal regions where the toxin is absorbed and the conditions favoring epsilon toxin absorption are unknown. The aim of this paper was to determine the toxicity of epsilon toxin absorbed from different gastrointestinal segments of mice and to evaluate the influence of the intestinal environment in the absorption of this toxin. Epsilon toxin diluted in one of several different saline solutions was surgically introduced into ligated stomach or intestinal segments of mice. Comparison of the toxicity of epsilon toxin injected in different sections of the gastrointestinal tract showed that this toxin can be absorbed from the small and the large intestine but not from the stomach of mice. The lethality of epsilon toxin was higher when this toxin was injected in the colon than in the small intestine. Low pH, and Na(+) and glucose added to the saline solution increased the toxicity of epsilon toxin injected into the small intestine. This study shows that absorption of epsilon toxin can occur in any intestinal segment of mice and that the physicochemical characteristics of the intestinal content can affect the absorption of this toxin.
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Affiliation(s)
- D M Losada-Eaton
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Universidad de Buenos Aires, Paraguay 2155, C1121ABG Buenos Aires, Argentina
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92
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Hughes ML, Poon R, Adams V, Sayeed S, Saputo J, Uzal FA, McClane BA, Rood JI. Epsilon-toxin plasmids of Clostridium perfringens type D are conjugative. J Bacteriol 2007; 189:7531-8. [PMID: 17720791 PMCID: PMC2168747 DOI: 10.1128/jb.00767-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Isolates of Clostridium perfringens type D produce the potent epsilon-toxin (a CDC/U.S. Department of Agriculture overlap class B select agent) and are responsible for several economically significant enterotoxemias of domestic livestock. It is well established that the epsilon-toxin structural gene, etx, occurs on large plasmids. We show here that at least two of these plasmids are conjugative. The etx gene on these plasmids was insertionally inactivated using a chloramphenicol resistance cassette to phenotypically tag the plasmid. High-frequency conjugative transfer of the tagged plasmids into the C. perfringens type A strain JIR325 was demonstrated, and the resultant transconjugants were shown to act as donors in subsequent mating experiments. We also demonstrated the transfer of "unmarked" native epsilon-toxin plasmids into strain JIR325 by exploiting the high transfer frequency. The transconjugants isolated in these experiments expressed functional epsilon-toxin since their supernatants had cytopathic effects on MDCK cells and were toxic in mice. Using the widely accepted multiplex PCR approach for toxin genotyping, these type A-derived transconjugants were genotypically type D. These findings have significant implications for the C. perfringens typing system since it is based on the toxin profile of each strain. Our study demonstrated the fluid nature of the toxinotypes and their dependence upon the presence or absence of toxin plasmids, some of which have for the first time been shown to be conjugative.
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Affiliation(s)
- Meredith L Hughes
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
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93
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Fernandez Miyakawa ME, Ibarra CA, Uzal FA. In vitro effects of Clostridium perfringens type D epsilon toxin on water and ion transport in ovine and caprine intestine. Anaerobe 2007; 9:145-9. [PMID: 16887702 DOI: 10.1016/s1075-9964(03)00069-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2002] [Revised: 04/11/2003] [Accepted: 05/20/2003] [Indexed: 11/21/2022]
Abstract
Clostridium perfringens type D produces enterotoxaemia in sheep, goats and other animals. The disease is caused by C. perfringens epsilon toxin, and while enterotoxaemia in goats is usually characterized by enterocolitis, the disease in sheep is characterized by systemic lesions (such as lung and brain oedema) with minor and inconsistent changes observed in the intestine. A possible explanation for these differences is that epsilon toxin is more promptly absorbed by sheep than goat intestine. In an attempt to clarify this, we examined the in vitro effects of epsilon toxin on sheep and goat intestine. Pieces of intestinal mucosa from recently slaughtered animals were mounted in a modified Ussing-type chamber where net water flux (J(w)), short-circuit current (I(sc)) and tissue conductance (G(t)) were simultaneously recorded. After 70 min of incubation with epsilon toxin a reduction in absorptive J(w) and an increase in I(sc) and G(t) were observed in colonic tissues of both sheep and goats, but no alterations were registered in the ileum of either species. These in vitro results show that epsilon toxin affects the transport function of the colonic mucosa but it does not seem to produce any transport alteration in the ileum mucosa.
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Affiliation(s)
- M E Fernandez Miyakawa
- Unidad de Salud Animal, Instituto Nacional de Tecnología Agropecuaria, Bariloche, Argentina
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94
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Chassin C, Bens M, de Barry J, Courjaret R, Bossu JL, Cluzeaud F, Ben Mkaddem S, Gibert M, Poulain B, Popoff MR, Vandewalle A. Pore-forming epsilon toxin causes membrane permeabilization and rapid ATP depletion-mediated cell death in renal collecting duct cells. Am J Physiol Renal Physiol 2007; 293:F927-37. [PMID: 17567938 DOI: 10.1152/ajprenal.00199.2007] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Clostridium perfringens epsilon toxin (ET) is a potent pore-forming cytotoxin causing fatal enterotoxemia in livestock. ET accumulates in brain and kidney, particularly in the renal distal-collecting ducts. ET binds and oligomerizes in detergent-resistant membranes (DRMs) microdomains and causes cell death. However, the causal linkage between membrane permeabilization and cell death is not clear. Here, we show that ET binds and forms 220-kDa insoluble complexes in plasma membrane DRMs of renal mpkCCD(cl4) collecting duct cells. Phosphatidylinositol-specific phospholipase C did not impair binding or the formation of ET complexes, suggesting that the receptor for ET is not GPI anchored. ET induced a dose-dependent fall in the transepithelial resistance and potential in confluent cells grown on filters, transiently stimulated Na+ absorption, and induced an inward ionic current and a sustained rise in [Ca2+]i. ET also induced rapid depletion of cellular ATP, and stimulated the AMP-activated protein kinase, a metabolic-sensing Ser/Thr kinase. ET also induced mitochondrial membrane permeabilization and mitochondrial-nuclear translocation of apoptosis-inducing factor, a potent caspase-independent cell death effector. Finally, ET induced cell necrosis characterized by a marked reduction in nucleus size without DNA fragmentation. DRM disruption by methyl-beta-cyclodextrin impaired ET oligomerization, and significantly reduced the influx of Na+ and [Ca2+]i, but did not impair ATP depletion and cell death caused by the toxin. These findings indicate that ET causes rapid necrosis of renal collecting duct cells and establish that ATP depletion-mediated cell death is not strictly correlated with the plasma membrane permeabilization and ion diffusion caused by the toxin.
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Affiliation(s)
- C Chassin
- Institut National de la Santé et de la Recherche Médicale U773, Centre de Recherche Biomédicale Bichat-Beaujon CRB3, Paris, France
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95
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Fernandez-Miyakawa ME, Sayeed S, Fisher DJ, Poon R, Adams V, Rood JI, McClane BA, Saputo J, Uzal FA. Development and application of an oral challenge mouse model for studying Clostridium perfringens type D infection. Infect Immun 2007; 75:4282-8. [PMID: 17562765 PMCID: PMC1951146 DOI: 10.1128/iai.00562-07] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridium perfringens type D isolates cause enterotoxemia in sheep, goats, and probably cattle. While the major disease signs and lesions of type D animal disease are usually attributed to epsilon toxin, a class B select agent, these bacteria typically produce several lethal toxins. Understanding of disease pathogenesis and development of improved vaccines are hindered by the lack of a small-animal model mimicking natural disease caused by type D isolates. Addressing this need, we developed an oral challenge mouse model of C. perfringens type D enterotoxemia. When BALB/c mice with a sealed anus were inoculated by intragastric gavage with type D isolates, 7 of 10 type D isolates were lethal, as defined by spontaneous death or severe clinical signs necessitating euthanasia. The lethalities of the seven type D isolates varied between 14 and 100%. Clinical signs in the lethally challenged mice included seizures, convulsions, hyperexcitability, and/or depression. Mild intestinal gas distention and brain edema were observed at necropsy in a few mice, while histology showed multifocal acute tubular necrosis of the kidney and edema in the lungs of most challenged mice that developed a clinical response. When the lethality of type D isolates in this model was compared with in vitro toxin production, only a limited correlation was observed. However, mice could be protected against lethality by intravenous passive immunization with an epsilon toxin antibody prior to oral challenge. This study provides an economical new model for studying the pathogenesis of C. perfringens type D infections.
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Affiliation(s)
- Mariano E Fernandez-Miyakawa
- California Animal Health and Food Safety Laboratory System, San Bernardino Branch, University of California--Davis, 105 West Central Avenue, San Bernardino, CA 92408, USA
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96
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Soler-Jover A, Dorca J, Popoff MR, Gibert M, Saura J, Tusell JM, Serratosa J, Blasi J, Martín-Satué M. Distribution of Clostridium perfringens epsilon toxin in the brains of acutely intoxicated mice and its effect upon glial cells. Toxicon 2007; 50:530-40. [PMID: 17572464 DOI: 10.1016/j.toxicon.2007.04.025] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 04/24/2007] [Accepted: 04/25/2007] [Indexed: 10/23/2022]
Abstract
Epsilon toxin (epsilon-toxin), produced by Clostridium perfringens types B and D, causes fatal enterotoxaemia in livestock. The disease is principally manifested as severe and often fatal neurological disturbance. Oedema of several organs, including the brain, is also a clinical sign related to microvascular damage. Recombinant epsilon-toxin-green fluorescence protein (epsilon-toxin-GFP) and epsilon-prototoxin-GFP have already been characterised as useful tools to track their distribution in intravenously injected mice, by means of direct fluorescence microscopy detection. The results shown here, using an acutely intoxicated mouse model, strongly suggest that epsilon-toxin-GFP, but not epsilon-prototoxin-GFP, not only causes oedema but is also able to cross the blood-brain barrier and accumulate in brain tissue. In some brain areas, epsilon-toxin-GFP is found bound to glial cells, both astrocytes and microglia. Moreover, cytotoxicity assays, performed with mixed glial primary cultures, demonstrate the cytotoxic effect of epsilon-toxin upon both astrocytes and microglial cells.
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Affiliation(s)
- Alex Soler-Jover
- Laboratori de Neurobiologia Cellular i Molecular, Departament de Patologia i Terapèutica Experimental, Campus de Bellvitge, Universitat de Barcelona-IDIBELL, Spain
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97
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McClain MS, Cover TL. Functional analysis of neutralizing antibodies against Clostridium perfringens epsilon-toxin. Infect Immun 2007; 75:1785-93. [PMID: 17261609 PMCID: PMC1865726 DOI: 10.1128/iai.01643-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 11/13/2006] [Accepted: 01/15/2007] [Indexed: 11/20/2022] Open
Abstract
The Clostridium perfringens epsilon-toxin causes a severe, often fatal illness (enterotoxemia) characterized by cardiac, pulmonary, kidney, and brain edema. In this study, we examined the activities of two neutralizing monoclonal antibodies against the C. perfringens epsilon-toxin. Both antibodies inhibited epsilon-toxin cytotoxicity towards cultured MDCK cells and inhibited the ability of the toxin to form pores in the plasma membranes of cells, as shown by staining cells with the membrane-impermeant dye 7-aminoactinomycin D. Using an antibody competition enzyme-linked immunosorbent assay (ELISA), a peptide array, and analysis of mutant toxins, we mapped the epitope recognized by one of the neutralizing monoclonal antibodies to amino acids 134 to 145. The antibody competition ELISA and analysis of mutant toxins suggest that the second neutralizing monoclonal antibody also recognizes an epitope in close proximity to this region. The region comprised of amino acids 134 to 145 overlaps an amphipathic loop corresponding to the putative membrane insertion domain of the toxin. Identifying the epitopes recognized by these neutralizing antibodies constitutes an important first step in the development of therapeutic agents that could be used to counter the effects of the epsilon-toxin.
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Affiliation(s)
- Mark S McClain
- Department of Medicine, Division of Infectious Diseases, A2200 Medical Center North, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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98
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Lobato F, Assis R, Abreu V, Souza Jr. M, Lima C, Salvarani F. Enterotoxemia em bovino. ARQ BRAS MED VET ZOO 2006. [DOI: 10.1590/s0102-09352006000500037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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99
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Layana JE, Fernandez Miyakawa ME, Uzal FA. Evaluation of different fluids for detection of Clostridium perfringens type D epsilon toxin in sheep with experimental enterotoxemia. Anaerobe 2006; 12:204-6. [PMID: 16857397 DOI: 10.1016/j.anaerobe.2006.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 05/18/2006] [Accepted: 05/18/2006] [Indexed: 11/22/2022]
Abstract
Enterotoxemia caused by Clostridium perfringens type D is a highly lethal disease of sheep, goats and other ruminants. The diagnosis of this condition is usually confirmed by detection of epsilon toxin, a major exotoxin produced by C. perfringens types B and D, in the intestinal content of affected animals. It has been suggested that other body fluids can also be used for detection of epsilon toxin. This study was performed to evaluate the usefulness of intestinal content versus other body fluids in detecting epsilon toxin in cases of sheep enterotoxemia. Samples of duodenal, ileal and colon contents, pericardial and abdominal fluids, aqueous humor and urine from 15 sheep with experimentally induced enterotoxemia, were analysed for epsilon toxin using a capture ELISA. Epsilon toxin was detected in 92% of the samples of ileal content, 64% of the samples of duodenal content, 57% of the samples of colon content and in 7% of the samples of pericardial fluid and aqueous humor. No epsilon toxin was found in samples of abdominal fluid or urine from the animals with enterotoxemia or in any samples from six clinically healthy sheep used as negative controls. The results of this study indicate that with the diagnostic capture ELISA used, intestinal content (preferably ileum) should be used for C. perfringens type D epsilon toxin detection in suspected cases of sheep enterotoxemia.
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Affiliation(s)
- Jorge E Layana
- The National Institute of Agricultural Technology. CC 277, (8400) Bariloche, Argentina
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100
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Sayeed S, Fernandez-Miyakawa ME, Fisher DJ, Adams V, Poon R, Rood JI, Uzal FA, McClane BA. Epsilon-toxin is required for most Clostridium perfringens type D vegetative culture supernatants to cause lethality in the mouse intravenous injection model. Infect Immun 2005; 73:7413-21. [PMID: 16239541 PMCID: PMC1273886 DOI: 10.1128/iai.73.11.7413-7421.2005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 06/27/2005] [Accepted: 07/27/2005] [Indexed: 11/20/2022] Open
Abstract
Clostridium perfringens type D enterotoxemias have significant economic impact by causing rapid death of several domestic animal species. Consequently, domestic animals are commonly vaccinated, at varying efficacy, with inactivated type D vegetative supernatants. Improved type D vaccines might become possible if the lethal toxins produced by type D isolates were characterized and the contributions of those toxins to supernatant-induced lethality were established. Therefore, the current study evaluated the presence of lethal toxins in supernatants prepared from late-log-phase vegetative cultures of a large collection of genotype D isolates. Under this growth condition, most genotype D isolates produced variable levels of at least three different lethal toxins, including epsilon-toxin (ETX). To model the rapid lethality of type D enterotoxemias, studies were conducted involving intravenous (i.v.) injection of genotype D vegetative supernatants into mice, which were then observed for neurotoxic distress. Those experiments demonstrated a correlation between ETX (but not alpha-toxin or perfringolysin O) levels in late-log-phase genotype D supernatants and lethality. Consistent with the known proteolytic activation requirement for ETX toxicity, trypsin pretreatment was required for, or substantially increased, the lethality of nearly all of the tested genotype D vegetative supernatants. Finally, the lethality of these trypsin-pretreated genotype D supernatants could be completely neutralized by an ETX-specific monoclonal antibody but not by an alpha-toxin-specific monoclonal antibody. Collectively, these results indicate that, under the experimental conditions used in the present study, ETX is necessary for the lethal properties of most genotype D vegetative supernatants in the mouse i.v. injection model.
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Affiliation(s)
- Sameera Sayeed
- E1240 BSTWR, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
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