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Shrestha A, Mehdizadeh Gohari I, Li J, Navarro M, Uzal FA, McClane BA. The biology and pathogenicity of Clostridium perfringens type F: a common human enteropathogen with a new(ish) name. Microbiol Mol Biol Rev 2024:e0014023. [PMID: 38864615 DOI: 10.1128/mmbr.00140-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024] Open
Abstract
SUMMARYIn the 2018-revised Clostridium perfringens typing classification system, isolates carrying the enterotoxin (cpe) and alpha toxin genes but no other typing toxin genes are now designated as type F. Type F isolates cause food poisoning and nonfoodborne human gastrointestinal (GI) diseases, which most commonly involve type F isolates carrying, respectivefooly, a chromosomal or plasmid-borne cpe gene. Compared to spores of other C. perfringens isolates, spores of type F chromosomal cpe isolates often exhibit greater resistance to food environment stresses, likely facilitating their survival in improperly prepared or stored foods. Multiple factors contribute to this spore resistance phenotype, including the production of a variant small acid-soluble protein-4. The pathogenicity of type F isolates involves sporulation-dependent C. perfringens enterotoxin (CPE) production. C. perfringens sporulation is initiated by orphan histidine kinases and sporulation-associated sigma factors that drive cpe transcription. CPE-induced cytotoxicity starts when CPE binds to claudin receptors to form a small complex (which also includes nonreceptor claudins). Approximately six small complexes oligomerize on the host cell plasma membrane surface to form a prepore. CPE molecules in that prepore apparently extend β-hairpin loops to form a β-barrel pore, allowing a Ca2+ influx that activates calpain. With low-dose CPE treatment, caspase-3-dependent apoptosis develops, while high-CPE dose treatment induces necroptosis. Those effects cause histologic damage along with fluid and electrolyte losses from the colon and small intestine. Sialidases likely contribute to type F disease by enhancing CPE action and, for NanI-producing nonfoodborne human GI disease isolates, increasing intestinal growth and colonization.
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Affiliation(s)
- Archana Shrestha
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Iman Mehdizadeh Gohari
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jihong Li
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Mauricio Navarro
- Instituto de Patologia Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Francisco A Uzal
- California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California Davis, San Bernardino, California, USA
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Ou L, Ye B, Sun M, Qi N, Li J, Lv M, Lin X, Cai H, Hu J, Song Y, Chen X, Zhu Y, Yin L, Zhang J, Liao S, Zhang H. Mechanisms of intestinal epithelial cell damage by Clostridiumperfringens. Anaerobe 2024; 87:102856. [PMID: 38609034 DOI: 10.1016/j.anaerobe.2024.102856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/31/2024] [Accepted: 04/09/2024] [Indexed: 04/14/2024]
Abstract
Clostridium perfringens, a Gram-positive bacterium, causes intestinal diseases in humans and livestock through its toxins, related to alpha toxin (CPA), beta toxin (CPB), C. perfringens enterotoxin (CPE), epsilon toxin (ETX), Iota toxin (ITX), and necrotic enteritis B-like toxin (NetB). These toxins disrupt intestinal barrier, leading to various cell death mechanisms such as necrosis, apoptosis, and necroptosis. Additionally, non-toxin factors like adhesins and degradative enzymes contribute to virulence by enhancing colonization and survival of C. perfringens. A vicious cycle of intestinal barrier breach, misregulated cell death, and subsequent inflammation is at the heart of chronic inflammatory and infectious gastrointestinal diseases. Understanding these mechanisms is essential for developing targeted therapies against C. perfringens-associated intestinal diseases.
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Affiliation(s)
- Lanxin Ou
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China; College of Life Science and Engineering, Foshan University, Foshan, 528225, China
| | - Bijin Ye
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China; College of Life Science and Engineering, Foshan University, Foshan, 528225, China
| | - Mingfei Sun
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Nanshan Qi
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Juan Li
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Minna Lv
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Xuhui Lin
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Haiming Cai
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Junjing Hu
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Yongle Song
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Xiangjie Chen
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Yibin Zhu
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Lijun Yin
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Jianfei Zhang
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Shenquan Liao
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Key Laboratory of Avian Influenza and Other Major Poultry Diseases Prevention and Control, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
| | - Haoji Zhang
- College of Life Science and Engineering, Foshan University, Foshan, 528225, China.
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Ogbu CP, Kapoor S, Vecchio AJ. Structural Basis of Clostridium perfringens Enterotoxin Activation and Oligomerization by Trypsin. Toxins (Basel) 2023; 15:637. [PMID: 37999500 PMCID: PMC10674488 DOI: 10.3390/toxins15110637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/18/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023] Open
Abstract
Clostridium perfringens enterotoxin (CpE) is a β-pore forming toxin that disrupts gastrointestinal homeostasis in mammals by binding membrane protein receptors called claudins. Although structures of CpE fragments bound to claudins have been determined, the mechanisms that trigger CpE activation and oligomerization that lead to the formation of cytotoxic β-pores remain undetermined. Proteolysis of CpE in the gut by trypsin has been shown to play a role in this and subsequent cytotoxicity processes. Here, we report solution structures of full-length and trypsinized CpE using small-angle X-ray scattering (SAXS) and crystal structures of trypsinized CpE and its C-terminal claudin-binding domain (cCpE) using X-ray crystallography. Mass spectrometry and SAXS uncover that removal of the CpE N-terminus by trypsin alters the CpE structure to expose areas that are normally unexposed. Crystal structures of trypsinized CpE and cCpE reveal unique dimer interfaces that could serve as oligomerization sites. Moreover, comparisons of these structures to existing ones predict the functional implications of oligomerization in the contexts of cell receptor binding and β-pore formation. This study sheds light on trypsin's role in altering CpE structure to activate its function via inducing oligomerization on its path toward cytotoxic β-pore formation. Its findings can incite new approaches to inhibit CpE-based cytotoxicity with oligomer-disrupting therapeutics.
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Affiliation(s)
| | | | - Alex J. Vecchio
- Department of Structural Biology, University at Buffalo, The State University of New York, Buffalo, NY 14203, USA; (C.P.O.); (S.K.)
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Characterizing the Contributions of Various Clostridium perfringens Enterotoxin Properties to In Vivo and In Vitro Permeability Effects. mSphere 2022; 7:e0027622. [PMID: 36069435 PMCID: PMC9599344 DOI: 10.1128/msphere.00276-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Clostridium perfringens enterotoxin (CPE) is thought to cause lethal enterotoxemia when absorbed from the intestinal lumen into the circulation. CPE action sequentially involves receptor-binding, oligomerization into a prepore, and pore formation. To explore the mechanistic basis by which CPE alters permeability, this study tested the permeability effects of several recombinant CPE (rCPE) species: rCPE and rCPEC186A (which form pores), rC-CPE and rCPED48A (which bind to receptors but cannot oligomerize), rCPEC186A/F91C (which binds and oligomerizes without pore formation), and rCPEY306A/L315A (which has poor receptor-binding ability). On Caco-2 cells, i) only rCPE and rCPEC186A were cytotoxic; ii) rCPE and rCPEC186A affected transepithelial resistance (TEER) and 4 kDa fluorescent dextran (FD4) transit more quickly than binding-capable, but noncytotoxic, rCPE variants; whereas iii) rCPEY306A/L315A did not affect TEER or FD4 transit. Using mouse intestinal loops, rCPE (but not noncytotoxic rC-CPE, rCPED48A or rCPEY306A/L315A) was lethal and caused intestinal histologic damage within 4 h. After 2 h of treatment, rCPE was more strongly absorbed into the serum than those noncytotoxic rCPE species but by 4 h rC-CPE and rCPED48A became absorbed similarly as rCPE, while rCPEY306A/L315A absorption remained low. This increased rC-CPE and rCPED48A absorption from 2 to 4 h did not involve a general intestinal permeability increase because Evans Blue absorption from the intestines did not increase between 2 and 4 h of treatment with rC-CPE or rCPED48A. Collectively, these results indicate that CPE receptor binding is sufficient to slowly affect permeability, but CPE-induced cytotoxicity is necessary for rapid permeability changes and lethality. IMPORTANCE Clostridium perfringens enterotoxin (CPE) causes lethal enterotoxemia when absorbed from the intestines into the bloodstream. Testing recombinant CPE (rCPE) or rCPE variants impaired for various specific steps in CPE action showed that full CPE-induced cytotoxicity causes rapid Caco-2 monolayer permeability alterations, as well as enterotoxemic lethality and rapid CPE absorption in mouse small intestinal loops. However, receptor binding-capable, but noncytotoxic, rCPE variants did cause slow-developing in vitro and in vivo permeability effects. Absorption of binding-capable, noncytotoxic rCPE variants from the intestines did not correlate with general intestinal permeability alterations, suggesting that CPE binding can induce its own uptake. These findings highlight the importance of binding and, especially, cytotoxicity for CPE absorption during enterotoxemia and may assist development of permeability-altering rCPE variants for translational purposes.
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Fathima S, Hakeem WGA, Shanmugasundaram R, Selvaraj RK. Necrotic Enteritis in Broiler Chickens: A Review on the Pathogen, Pathogenesis, and Prevention. Microorganisms 2022; 10:microorganisms10101958. [PMID: 36296234 PMCID: PMC9610872 DOI: 10.3390/microorganisms10101958] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 11/06/2022] Open
Abstract
Clostridium perfringens type A and C are the primary etiological agents associated with necrotic enteritis (NE) in poultry. The predisposing factors implicated in the incidence of NE changes the physical properties of the gut, immunological status of birds, and disrupt the gut microbial homeostasis, causing an over-proliferation of C. perfringens. The principal virulence factors contributing to the pathogenesis of NE are the α-toxin, β-toxin, and NetB toxin. The immune response to NE in poultry is mediated by the Th1 pathway or cytotoxic T-lymphocytes. C. perfringens type A and C are also pathogenic in humans, and hence are of public health significance. C. perfringens intoxications are the third most common bacterial foodborne disease after Salmonella and Campylobacter. The restrictions on the use of antibiotics led to an increased incidence of NE in poultry. Hence, it is essential to develop alternative strategies to keep the prevalence of NE under check. The control strategies rely principally on the positive modulation of host immune response, nutritional manipulation, and pathogen reduction. Current knowledge on the etiology, pathogenesis, predisposing factors, immune response, effect on the gut microbial homeostasis, and preventative strategies of NE in this post-antibiotic era is addressed in this review.
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Affiliation(s)
- Shahna Fathima
- Department of Poultry Science, The University of Georgia, Athens, GA 30602, USA
| | | | - Revathi Shanmugasundaram
- Toxicology and Mycotoxin Research Unit, US National Poultry Research Center, Athens, GA 30605, USA
| | - Ramesh K. Selvaraj
- Department of Poultry Science, The University of Georgia, Athens, GA 30602, USA
- Correspondence:
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Orlando BJ, Dominik PK, Roy S, Ogbu CP, Erramilli SK, Kossiakoff AA, Vecchio AJ. Development, structure, and mechanism of synthetic antibodies that target claudin and Clostridium perfringens enterotoxin complexes. J Biol Chem 2022; 298:102357. [PMID: 35952760 PMCID: PMC9463536 DOI: 10.1016/j.jbc.2022.102357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/15/2022] Open
Abstract
Strains of Clostridium perfringens produce a two-domain enterotoxin (CpE) that afflicts humans and domesticated animals, causing prevalent gastrointestinal illnesses. CpE’s C-terminal domain (cCpE) binds cell surface receptors, followed by a restructuring of its N-terminal domain to form a membrane-penetrating β-barrel pore, which is toxic to epithelial cells of the gut. The claudin family of membrane proteins are known receptors for CpE and also control the architecture and function of cell-cell contacts (tight junctions) that create barriers to intercellular molecular transport. CpE binding and assembly disables claudin barrier function and induces cytotoxicity via β-pore formation, disrupting gut homeostasis; however, a structural basis of this process and strategies to inhibit the claudin–CpE interactions that trigger it are both lacking. Here, we used a synthetic antigen-binding fragment (sFab) library to discover two sFabs that bind claudin-4 and cCpE complexes. We established these sFabs’ mode of molecular recognition and binding properties and determined structures of each sFab bound to claudin-4–cCpE complexes using cryo-EM. The structures reveal that the sFabs bind a shared epitope, but conform distinctly, which explains their unique binding equilibria. Mutagenesis of antigen/sFab interfaces observed therein result in binding changes, validating the structures, and uncovering the sFab’s targeting mechanism. From these insights, we generated a model for CpE’s claudin-bound β-pore that predicted sFabs would not prevent cytotoxicity, which we then verified in vivo. Taken together, this work demonstrates the development and mechanism of claudin/cCpE-binding sFabs that provide a framework and strategy for obstructing claudin/CpE assembly to treat CpE-linked gastrointestinal diseases.
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Affiliation(s)
- Benjamin J Orlando
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824 USA
| | - Pawel K Dominik
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637 USA
| | - Sourav Roy
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588 USA
| | - Chinemerem P Ogbu
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588 USA
| | - Satchal K Erramilli
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637 USA
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637 USA
| | - Alex J Vecchio
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588 USA.
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Disruption of Claudin-Made Tight Junction Barriers by Clostridium perfringens Enterotoxin: Insights from Structural Biology. Cells 2022; 11:cells11050903. [PMID: 35269525 PMCID: PMC8909277 DOI: 10.3390/cells11050903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/26/2022] [Accepted: 03/02/2022] [Indexed: 02/01/2023] Open
Abstract
Claudins are a family of integral membrane proteins that enable epithelial cell/cell interactions by localizing to and driving the formation of tight junctions. Via claudin self-assembly within the membranes of adjoining cells, their extracellular domains interact, forming barriers to the paracellular transport of small molecules and ions. The bacterium Clostridium perfringens causes prevalent gastrointestinal disorders in mammals by employing an enterotoxin (CpE) that targets claudins. CpE binds to claudins at or near tight junctions in the gut and disrupts their barrier function, potentially by disabling their assembly or via cell signaling means—the mechanism(s) remain unclear. CpE ultimately destroys claudin-expressing cells through the formation of a cytotoxic membrane-penetrating β-barrel pore. Structures obtained by X-ray crystallography of CpE, claudins, and claudins in complex with CpE fragments have provided the structural bases of claudin and CpE functions, revealing potential mechanisms for the CpE-mediated disruption of claudin-made tight junctions. This review highlights current progress in this space—what has been discovered and what remains unknown—toward efforts to elucidate the molecular mechanism of CpE disruption of tight junction barriers. It further underscores the key insights obtained through structure that are being applied to develop CpE-based therapeutics that combat claudin-overexpressing cancers or modulate tight junction barriers.
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NanI Sialidase Enhances the Action of Clostridium perfringens Enterotoxin in the Presence of Mucus. mSphere 2021; 6:e0084821. [PMID: 34908460 PMCID: PMC8673254 DOI: 10.1128/msphere.00848-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) is the main virulence factor for C. perfringens type F strains to cause human gastrointestinal diseases, which can involve lethal enterotoxemia. During type F disease, CPE encounters an adherent mucus layer overlying the intestines, so the current study evaluated if NanI potentiates CPE activity in the presence of adherent mucus. CPE alone caused more cytotoxicity transepithelial electrical resistance (TEER) and permeability to fluorescent dextran (FD) for minimal mucus-producing HT29 cells versus that in their derivative HT29-MTX-E12 cells, which produce abundant adherent mucus. However, for HT29-MTX-E12 cells, the presence of NanI significantly increased CPE binding and pore formation, which enhanced their sensitivity to CPE effects on cytotoxicity, TEER, and FD permeability. When the ability of NanI to potentiate CPE-induced enterotoxemia was then tested in a mouse small intestinal loop enterotoxemia model, a pathophysiologically relevant 50 μg/mL dose of CPE did not kill mice. However, the copresence of purified NanI resulted in significant CPE-induced lethality. More CPE was detected in the sera of mice challenged with 50 μg/mL of CPE when NanI was copresent during challenge. The copresence of NanI and CPE during challenge also significantly increased intestinal histologic damage compared to that after challenge with CPE alone, suggesting that NanI enhancement of CPE-induced intestinal damage may increase CPE absorption into blood. Overall, these results indicate that (i) mucus inhibits CPE action and (ii) NanI can potentiate CPE action in the presence of mucus, which may help explain why type F strains that produce relatively low levels of CPE are still pathogenic. IMPORTANCE NanI is a sialidase produced by some Clostridium perfringens type F strains. Here, we found that NanI can significantly increase the action of C. perfringens enterotoxin (CPE), which is the main toxin responsible for severe human enteric disease caused by type F strains. This effect likely helps to explain why even some type F strains that produce small amounts of CPE are pathogenic.
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Mehdizadeh Gohari I, A. Navarro M, Li J, Shrestha A, Uzal F, A. McClane B. Pathogenicity and virulence of Clostridium perfringens. Virulence 2021; 12:723-753. [PMID: 33843463 PMCID: PMC8043184 DOI: 10.1080/21505594.2021.1886777] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022] Open
Abstract
Clostridium perfringens is an extremely versatile pathogen of humans and livestock, causing wound infections like gas gangrene (clostridial myonecrosis), enteritis/enterocolitis (including one of the most common human food-borne illnesses), and enterotoxemia (where toxins produced in the intestine are absorbed and damage distant organs such as the brain). The virulence of this Gram-positive, spore-forming, anaerobe is largely attributable to its copious toxin production; the diverse actions and roles in infection of these toxins are now becoming established. Most C. perfringens toxin genes are encoded on conjugative plasmids, including the pCW3-like and the recently discovered pCP13-like plasmid families. Production of C. perfringens toxins is highly regulated via processes involving two-component regulatory systems, quorum sensing and/or sporulation-related alternative sigma factors. Non-toxin factors, such as degradative enzymes like sialidases, are also now being implicated in the pathogenicity of this bacterium. These factors can promote toxin action in vitro and, perhaps in vivo, and also enhance C. perfringens intestinal colonization, e.g. NanI sialidase increases C. perfringens adherence to intestinal tissue and generates nutrients for its growth, at least in vitro. The possible virulence contributions of many other factors, such as adhesins, the capsule and biofilms, largely await future study.
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Affiliation(s)
- Iman Mehdizadeh Gohari
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Mauricio A. Navarro
- California Animal Health and Food Safety Laboratory, School of Veterinary Medicine, University of California Davis, San Bernardino, CA, USA
| | - Jihong Li
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Archana Shrestha
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Francisco Uzal
- California Animal Health and Food Safety Laboratory, School of Veterinary Medicine, University of California Davis, San Bernardino, CA, USA
| | - Bruce A. McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Effective Oncoleaking Treatment of Pancreatic Cancer by Claudin-Targeted Suicide Gene Therapy with Clostridium perfringens Enterotoxin (CPE). Cancers (Basel) 2021; 13:cancers13174393. [PMID: 34503203 PMCID: PMC8431234 DOI: 10.3390/cancers13174393] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/20/2021] [Accepted: 08/25/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Current therapies for pancreas carcinoma (PC) are of limited efficacy due to tumor aggressiveness and therapy resistance. Bacterial toxins with pore-forming (oncoleaking) potential are promising tools in cancer therapy. We have developed a novel, suicide gene therapy treatment, based on Clostridium perfringens enterotoxin (CPE)-mediated oncoleaking. This is achieved by CPE suicide gene therapy to treat PC, which overexpresses the claudin-3 and -4 (Cldn3/4) tight junction proteins, which are targets of CPE action. This targeted gene therapy causes rapid eradication of Cldn3/4 overexpressing PC cells via oncoleaking and initiation of apoptotic/necrotic signaling. We demonstrate efficacy of this approach in vitro and after nonviral in vivo gene transfer in cell lines and in patient derived xenograft PC models. This therapy approach has translational potential for treatment of pancreas carcinomas and could also be translated into new combination settings with conventional chemotherapy. Abstract Pancreatic cancer (PC) is one of the most lethal cancers worldwide, associated with poor prognosis and restricted therapeutic options. Clostridium perfringens enterotoxin (CPE), is a pore-forming (oncoleaking) toxin, which binds to claudin-3 and -4 (Cldn3/4) causing selective cytotoxicity. Cldn3/4 are highly upregulated in PC and represent an effective target for oncoleaking therapy. We utilized a translation-optimized CPE vector (optCPE) for new suicide approach of PC in vitro and in cell lines (CDX) and patient-derived pancreatic cancer xenografts (PDX) in vivo. The study demonstrates selective toxicity in Cldn3/4 overexpressing PC cells by optCPE gene transfer, mediated by pore formation, activation of apoptotic/necrotic signaling in vitro, induction of necrosis and of bystander tumor cell killing in vivo. The optCPE non-viral intratumoral in vivo jet-injection gene therapy shows targeted antitumoral efficacy in different CDX and PDX PC models, leading to reduced tumor viability and induction of tumor necrosis, which is further enhanced if combined with chemotherapy. This selective oncoleaking suicide gene therapy improves therapeutic efficacy in pancreas carcinoma and will be of value for better local control, particularly of unresectable or therapy refractory PC.
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Innovative and Highly Sensitive Detection of Clostridium perfringens Enterotoxin Based on Receptor Interaction and Monoclonal Antibodies. Toxins (Basel) 2021; 13:toxins13040266. [PMID: 33917845 PMCID: PMC8068247 DOI: 10.3390/toxins13040266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/03/2021] [Accepted: 04/06/2021] [Indexed: 11/16/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) regularly causes food poisoning and antibiotic-associated diarrhea; therefore, reliable toxin detection is crucial. To this aim, we explored stationary and mobile strategies to detect CPE either exclusively by monoclonal antibodies (mAbs) or, alternatively, by toxin-enrichment via the cellular receptor of CPE, claudin-4, and mAb detection. Among the newly generated mAbs, we identified nine CPE-specific mAbs targeting five distinct epitopes, among them mAbs recognizing CPE bound to claudin-4 or neutralizing CPE activity in vitro. In surface plasmon resonance experiments, all mAbs and claudin-4 revealed excellent affinities towards CPE, ranging from 0.05 to 2.3 nM. Integrated into sandwich enzyme-linked immunosorbent assays (ELISAs), the most sensitive mAb/mAb and claudin-4/mAb combinations achieved similar detection limits of 0.3 pg/mL and 1.0 pg/mL, respectively, specifically detecting recombinant CPE from spiked feces and native CPE from 30 different C. perfringens culture supernatants. The implementation of mAb- and receptor-based ELISAs into a mobile detection platform enabled the fast detection of CPE, which will be helpful in clinical laboratories to diagnose diarrhea of assumed bacterial origin. In conclusion, we successfully employed an endogenous receptor and novel high affinity mAbs for highly sensitive and specific CPE-detection. These tools will be useful for both basic and applied research.
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Asadpoor M, Ithakisiou GN, Henricks PAJ, Pieters R, Folkerts G, Braber S. Non-Digestible Oligosaccharides and Short Chain Fatty Acids as Therapeutic Targets against Enterotoxin-Producing Bacteria and Their Toxins. Toxins (Basel) 2021; 13:175. [PMID: 33668708 PMCID: PMC7996226 DOI: 10.3390/toxins13030175] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/08/2021] [Accepted: 02/17/2021] [Indexed: 02/07/2023] Open
Abstract
Enterotoxin-producing bacteria (EPB) have developed multiple mechanisms to disrupt gut homeostasis, and provoke various pathologies. A major part of bacterial cytotoxicity is attributed to the secretion of virulence factors, including enterotoxins. Depending on their structure and mode of action, enterotoxins intrude the intestinal epithelium causing long-term consequences such as hemorrhagic colitis. Multiple non-digestible oligosaccharides (NDOs), and short chain fatty acids (SCFA), as their metabolites produced by the gut microbiota, interact with enteropathogens and their toxins, which may result in the inhibition of the bacterial pathogenicity. NDOs characterized by diverse structural characteristics, block the pathogenicity of EPB either directly, by inhibiting bacterial adherence and growth, or biofilm formation or indirectly, by promoting gut microbiota. Apart from these abilities, NDOs and SCFA can interact with enterotoxins and reduce their cytotoxicity. These anti-virulent effects mostly rely on their ability to mimic the structure of toxin receptors and thus inhibiting toxin adherence to host cells. This review focuses on the strategies of EPB and related enterotoxins to impair host cell immunity, discusses the anti-pathogenic properties of NDOs and SCFA on EPB functions and provides insight into the potential use of NDOs and SCFA as effective agents to fight against enterotoxins.
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Affiliation(s)
- Mostafa Asadpoor
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands; (M.A.); (G.-N.I.); (P.A.J.H.); (G.F.)
| | - Georgia-Nefeli Ithakisiou
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands; (M.A.); (G.-N.I.); (P.A.J.H.); (G.F.)
| | - Paul A. J. Henricks
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands; (M.A.); (G.-N.I.); (P.A.J.H.); (G.F.)
| | - Roland Pieters
- Division of Medicinal Chemistry and Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands;
| | - Gert Folkerts
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands; (M.A.); (G.-N.I.); (P.A.J.H.); (G.F.)
| | - Saskia Braber
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands; (M.A.); (G.-N.I.); (P.A.J.H.); (G.F.)
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Baumholtz AI, De Marco P, Capra V, Ryan AK. Functional Validation of CLDN Variants Identified in a Neural Tube Defect Cohort Demonstrates Their Contribution to Neural Tube Defects. Front Neurosci 2020; 14:664. [PMID: 32760237 PMCID: PMC7372130 DOI: 10.3389/fnins.2020.00664] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 05/29/2020] [Indexed: 12/27/2022] Open
Abstract
Neural tube defects (NTDs) are severe malformations of the central nervous system that affect 1–2 individuals per 2,000 births. Their etiology is complex and involves both genetic and environmental factors. Our recent discovery that simultaneous removal of Cldn3, -4, and -8 from tight junctions results in cranial and spinal NTDs in both chick and mouse embryos suggests that claudins play a conserved role in neural tube closure in vertebrates. To determine if claudins were associated with NTDs in humans, we used a Fluidigm next generation sequencing approach to identify genetic variants in CLDN loci in 152 patients with spinal NTDs. We identified eleven rare and four novel missense mutations in ten CLDN genes. In vivo validation of variant pathogenicity using a chick embryo model system revealed that overexpression of four variants caused a significant increase in NTDs: CLDN3 A128T, CLDN8 P216L, CLDN19 I22T, and E209G. Our data implicate rare missense variants in CLDN genes as risk factors for spinal NTDs and suggest a new family of proteins involved in the pathogenesis of these malformations.
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Affiliation(s)
- Amanda I Baumholtz
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,The Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Patrizia De Marco
- Laboratorio di Neurogenetica e Neuroscienze, Istituto Giannina Gaslini, Genoa, Italy
| | - Valeria Capra
- U.O. Neurochirurgia, Istituto Giannina Gaslini, Genoa, Italy
| | - Aimee K Ryan
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,The Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Department of Pediatrics, McGill University, Montreal, QC, Canada
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Huber P. Targeting of the apical junctional complex by bacterial pathogens. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183237. [DOI: 10.1016/j.bbamem.2020.183237] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 02/06/2020] [Accepted: 02/10/2020] [Indexed: 12/17/2022]
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Clostridium perfringens Epsilon-Toxin Impairs the Barrier Function in MDCK Cell Monolayers in a Ca 2+-Dependent Manner. Toxins (Basel) 2020; 12:toxins12050286. [PMID: 32365779 PMCID: PMC7291203 DOI: 10.3390/toxins12050286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/21/2020] [Accepted: 04/28/2020] [Indexed: 12/27/2022] Open
Abstract
Epsilon-toxin produced by Clostridium perfringens significantly contributes to the pathogeneses of enterotoxemia in ruminants and multiple sclerosis in humans. Epsilon-toxin forms a heptameric oligomer in the host cell membrane, promoting cell disruption. Here, we investigate the effect of epsilon-toxin on epithelial barrier functions. Epsilon-toxin impairs the barrier integrity of Madin-Darby Canine Kidney (MDCK) cells, as demonstrated by decreased transepithelial electrical resistance (TEER), increased paracellular flux marker permeability, and the decreased cellular localization of junctional proteins, such as occludin, ZO-1, and claudin-1. U73122, an endogenous phospholipase C (PLC) inhibitor, inhibited the decrease in TEER and the increase in the permeability of flux marker induced by epsilon-toxin. The application of epsilon-toxin to MDCK cells resulted in the biphasic formation of 1,2-diacylglycerol (DAG) and inositol-1,4,5-triphosphate (IP3). U73122 blocked the formation of DAG and IP3 induced by the toxin. Epsilon-toxin also specifically activated endogenous PLC-γ1. Epsilon-toxin dose-dependently increased the cytosolic calcium ion concentration ([Ca2+]i). The toxin-induced elevation of [Ca2+]i was inhibited by U73122. Cofilin is a key regulator of actin cytoskeleton turnover and tight-junction (TJ) permeability regulation. Epsilon-toxin caused cofilin dephosphorylation. These results demonstrate that epsilon-toxin induces Ca2+ influx through activating the phosphorylation of PLC-γ1 and then causes TJ opening accompanied by cofilin dephosphorylation.
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Abstract
C. perfringens type F strains are a common cause of food poisoning and antibiotic-associated diarrhea. Type F strain virulence requires production of C. perfringens enterotoxin (CPE). In Caco-2 cells, high CPE concentrations cause necrosis while low enterotoxin concentrations induce apoptosis. The current study determined that receptor-interacting serine/threonine-protein kinases 1 and 3 are involved in both CPE-induced apoptosis and necrosis in Caco-2 cells, while mixed-lineage kinase domain-like pseudokinase (MLKL) oligomerization is involved in CPE-induced necrosis, thereby indicating that this form of CPE-induced cell death involves necroptosis. High CPE concentrations also caused necroptosis in T84 and Vero cells. Calpain activation was identified as a key intermediate for CPE-induced necroptosis. These results suggest inhibitors of RIP1, RIP3, MLKL oligomerization, or calpain are useful therapeutics against CPE-mediated diseases. Clostridium perfringens type F strains cause gastrointestinal disease when they produce a pore-forming toxin named C. perfringens enterotoxin (CPE). In human enterocyte-like Caco-2 cells, low CPE concentrations cause caspase-3-dependent apoptosis, while high CPE concentrations cause necrosis. Since necrosis or apoptosis sometimes involves receptor-interacting serine/threonine-protein kinase-1 or 3 (RIP1 or RIP3), this study examined whether those kinases are important for CPE-induced apoptosis or necrosis. Highly specific RIP1 or RIP3 inhibitors reduced both CPE-induced apoptosis and necrosis in Caco-2 cells. Those findings suggested that the form of necrosis induced by treating Caco-2 cells with high CPE concentrations involves necroptosis, which was confirmed when high, but not low, CPE concentrations were shown to induce oligomerization of mixed-lineage kinase domain-like pseudokinase (MLKL), a key late step in necroptosis. Furthermore, an MLKL oligomerization inhibitor reduced cell death caused by high, but not low, CPE concentrations. Supporting RIP1 and RIP3 involvement in CPE-induced necroptosis, inhibitors of those kinases also reduced MLKL oligomerization during treatment with high CPE concentrations. Calpain inhibitors similarly blocked MLKL oligomerization induced by high CPE concentrations, implicating calpain activation as a key intermediate in initiating CPE-induced necroptosis. In two other CPE-sensitive cell lines, i.e., Vero cells and human enterocyte-like T84 cells, low CPE concentrations also caused primarily apoptosis/late apoptosis, while high CPE concentrations mainly induced necroptosis. Collectively, these results establish that high, but not low, CPE concentrations cause necroptosis and suggest that RIP1, RIP3, MLKL, or calpain inhibitors can be explored as potential therapeutics against CPE effects in vivo.
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Effects of Claudin-1 on the Action of Clostridium perfringens Enterotoxin in Caco-2 Cells. Toxins (Basel) 2019; 11:toxins11100582. [PMID: 31601044 PMCID: PMC6832201 DOI: 10.3390/toxins11100582] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 12/11/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) contributes to diarrhea and an often-lethal enterotoxemia. CPE action starts when it binds to claudin receptors, forming a small complex (90 kDa). Six small complexes then oligomerize to create prepores, followed by insertion of beta-hairpins from CPE to form beta-barrel pores named CH-1 or CH-2. Of the ~27 members of the human claudin protein family, only some bind CPE. However, both receptor claudins and the nonreceptor claudin-1 (CLDN-1) are associated with the small and CH-1/CH-2 CPE complexes. Therefore, this study evaluated whether claudin-1 affects CPE action by generating a CLDN-1 null mutant in Caco-2 cells using CRISPR-Cas9. Compared to wild-type Caco-2 cells, paracellular permeability of the CLDN-1 mutant was significantly enhanced, suggesting that claudin-1 may reduce CPE absorption during enterotoxemia. The CLDN-1 mutant was also markedly more sensitive than wild-type Caco-2 cells to apically-applied CPE. The mechanism behind this increased sensitivity involved higher CPE binding by the CLDN-1 mutant vs. wild-type Caco-2 cells, which led to more CH-1/CH-2 complex formation. However, the CH-1/CH-2 complexes formed by the CLDN-1 mutant were less stable or trypsin resistant than those of wild-type cells. These results indicate that, although a nonreceptor, CLDN-1 positively and negatively influences CPE action.
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Lan H, Hosomi K, Kunisawa J. Clostridium perfringens enterotoxin-based protein engineering for the vaccine design and delivery system. Vaccine 2019; 37:6232-6239. [PMID: 31466706 DOI: 10.1016/j.vaccine.2019.08.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 08/02/2019] [Indexed: 02/07/2023]
Abstract
Clostridium perfringens is a major cause of food poisoning worldwide, with its enterotoxin (CPE) being the major virulence factor. The C-terminus of CPE (C-CPE) is non-toxic and is the part of the toxin that binds to epithelial cells via the claudins in tight junctions; however, C-CPE has low antigenicity. To address this issue, we have used protein engineering technology to augment the antigenicity of C-CPE and have developed a C-CPE-based vaccine against C. perfringens-mediated food poisoning. Moreover, C-CPE has properties that make it potentially useful for the development of vaccines against other bacterial toxins that cause food poisoning. For example, we hypothesized that the ability of C-CPE to bind to claudins could be harnessed to deliver vaccine antigens directly to mucosa-associated lymphoid tissues, and we successfully developed a nasally administered C-CPE-based vaccine delivery system that promotes antigen-specific mucosal and systemic immune responses. In addition, our group has revealed the roles that the nasal mucus plays in lowering the efficacy of C-CPE-based nasal vaccines. Here, we review recent advances in the development of C-CPE-based vaccines against the major bacterial toxins that cause food poisoning and discuss our C-CPE-based nasal vaccine delivery system.
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Affiliation(s)
- Huangwenxian Lan
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan; Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan.
| | - Koji Hosomi
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan.
| | - Jun Kunisawa
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka, Japan; Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan; Division of Mucosal Immunology, Department of Microbiology and Immunology and International Research and Development Center for Mucosal Vaccines, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan; Kobe University Graduate School of Medicine, Hyogo, Japan; Graduate School of Medicine and Graduate School of Dentistry, Osaka University, Osaka, Japan.
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Potential Therapeutic Effects of Mepacrine against Clostridium perfringens Enterotoxin in a Mouse Model of Enterotoxemia. Infect Immun 2019; 87:IAI.00670-18. [PMID: 30642896 DOI: 10.1128/iai.00670-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/06/2019] [Indexed: 01/06/2023] Open
Abstract
Clostridium perfringens enterotoxin (CPE) is a pore-forming toxin that causes the symptoms of common bacterial food poisoning and several non-foodborne human gastrointestinal diseases, including antibiotic-associated diarrhea and sporadic diarrhea. In some cases, CPE-mediated disease can be very severe or fatal due to the involvement of enterotoxemia. Therefore, the development of potential therapeutics against CPE action during enterotoxemia is warranted. Mepacrine, an acridine derivative drug with broad-spectrum effects on pores and channels in mammalian membranes, has been used to treat protozoal intestinal infections in human patients. A previous study showed that the presence of mepacrine inhibits CPE-induced pore formation and activity in enterocyte-like Caco-2 cells, reducing the cytotoxicity caused by this toxin in vitro Whether mepacrine is similarly protective against CPE action in vivo has not been tested. When the current study evaluated whether mepacrine protects against CPE-induced death and intestinal damage using a murine ligated intestinal loop model, mepacrine protected mice from the enterotoxemic lethality caused by CPE. This protection was accompanied by a reduction in the severity of intestinal lesions induced by the toxin. Mepacrine did not reduce CPE pore formation in the intestine but inhibited absorption of the toxin into the blood of some mice. Protection from enterotoxemic death correlated with the ability of this drug to reduce CPE-induced hyperpotassemia. These in vivo findings, coupled with previous in vitro studies, support mepacrine as a potential therapeutic against CPE-mediated enterotoxemic disease.
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Abstract
In humans and livestock, Clostridium perfringens is an important cause of intestinal infections that manifest as enteritis, enterocolitis, or enterotoxemia. This virulence is largely related to the toxin-producing ability of C. perfringens. This article primarily focuses on the C. perfringens type F strains that cause a very common type of human food poisoning and many cases of nonfoodborne human gastrointestinal diseases. The enteric virulence of type F strains is dependent on their ability to produce C. perfringens enterotoxin (CPE). CPE has a unique amino acid sequence but belongs structurally to the aerolysin pore-forming toxin family. The action of CPE begins with binding of the toxin to claudin receptors, followed by oligomerization of the bound toxin into a prepore on the host membrane surface. Each CPE molecule in the prepore then extends a beta-hairpin to form, collectively, a beta-barrel membrane pore that kills cells by increasing calcium influx. The cpe gene is typically encoded on the chromosome of type F food poisoning strains but is encoded by conjugative plasmids in nonfoodborne human gastrointestinal disease type F strains. During disease, CPE is produced when C. perfringens sporulates in the intestines. Beyond type F strains, C. perfringens type C strains producing beta-toxin and type A strains producing a toxin named CPILE or BEC have been associated with human intestinal infections. C. perfringens is also an important cause of enteritis, enterocolitis, and enterotoxemia in livestock and poultry due to intestinal growth and toxin production.
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Developing a link between toxicants, claudins and neural tube defects. Reprod Toxicol 2018; 81:155-167. [DOI: 10.1016/j.reprotox.2018.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/27/2018] [Accepted: 08/02/2018] [Indexed: 02/06/2023]
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Benz R, Popoff MR. Clostridium perfringens Enterotoxin: The Toxin Forms Highly Cation-Selective Channels in Lipid Bilayers. Toxins (Basel) 2018; 10:toxins10090341. [PMID: 30135397 PMCID: PMC6162509 DOI: 10.3390/toxins10090341] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/14/2018] [Accepted: 08/14/2018] [Indexed: 02/07/2023] Open
Abstract
One of the numerous toxins produced by Clostridium perfringens is Clostridium perfringens enterotoxin (CPE), a polypeptide with a molecular mass of 35.5 kDa exhibiting three different domains. Domain one is responsible for receptor binding, domain two is involved in hexamer formation and domain three has to do with channel formation in membranes. CPE is the major virulence factor of this bacterium and acts on the claudin-receptor containing tight junctions between epithelial cells resulting in various gastrointestinal diseases. The activity of CPE on Vero cells was demonstrated by the entry of propidium iodide (PI) in the cells. The entry of propidium iodide caused by CPE was well correlated with the loss of cell viability monitored by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. CPE formed ion-permeable channels in artificial lipid bilayer membranes with a single-channel conductance of 620 pS in 1 M KCl. The single-channel conductance was not a linear function of the bulk aqueous salt concentration indicating that point-negative charges at the CPE channel controlled ion transport. This resulted in the high cation selectivity of the CPE channels, which suggested that anions are presumably not permeable through the CPE channels. The possible role of cation transport by CPE channels in disease caused by C. perfringens is discussed.
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Affiliation(s)
- Roland Benz
- Department of Life Sciences and Chemistry, Jacobs University, Campusring 1, 28759 Bremen, Germany.
| | - Michel R Popoff
- Bacterial Toxins, Institut Pasteur, 28 rue du Dr Roux, 75015 Paris, France.
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Freedman JC, Navarro MA, Morrell E, Beingesser J, Shrestha A, McClane BA, Uzal FA. Evidence that Clostridium perfringens Enterotoxin-Induced Intestinal Damage and Enterotoxemic Death in Mice Can Occur Independently of Intestinal Caspase-3 Activation. Infect Immun 2018; 86:e00931-17. [PMID: 29685988 PMCID: PMC6013662 DOI: 10.1128/iai.00931-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/15/2018] [Indexed: 01/13/2023] Open
Abstract
Clostridium perfringens enterotoxin (CPE) is responsible for the gastrointestinal symptoms of C. perfringens type A food poisoning and some cases of nonfoodborne gastrointestinal diseases, such as antibiotic-associated diarrhea. In the presence of certain predisposing medical conditions, this toxin can also be absorbed from the intestines to cause enterotoxemic death. CPE action in vivo involves intestinal damage, which begins at the villus tips. The cause of this CPE-induced intestinal damage is unknown, but CPE can induce caspase-3-mediated apoptosis in cultured enterocyte-like Caco-2 cells. Therefore, the current study evaluated whether CPE activates caspase-3 in the intestines and, if so, whether this effect is required for the development of intestinal tissue damage or enterotoxemic lethality. Using a mouse ligated small intestinal loop model, CPE was shown to cause intestinal caspase-3 activation in a dose- and time-dependent manner. Most of this caspase-3 activation occurred in epithelial cells shed from villus tips. However, CPE-induced caspase-3 activation occurred after the onset of tissue damage. Furthermore, inhibition of intestinal caspase-3 activity did not affect the onset of intestinal tissue damage. Similarly, inhibition of intestinal caspase-3 activity did not reduce CPE-induced enterotoxemic lethality in these mice. Collectively, these results demonstrate that caspase-3 activation occurs in the CPE-treated intestine but that this effect is not necessary for the development of CPE-induced intestinal tissue damage or enterotoxemic lethality.
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Affiliation(s)
- John C Freedman
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Mauricio A Navarro
- California Animal Health and Food Safety Laboratory, San Bernardino Branch, School of Veterinary Medicine, University of California-Davis, San Bernardino, California, USA
| | - Eleonora Morrell
- California Animal Health and Food Safety Laboratory, San Bernardino Branch, School of Veterinary Medicine, University of California-Davis, San Bernardino, California, USA
| | - Juliann Beingesser
- California Animal Health and Food Safety Laboratory, San Bernardino Branch, School of Veterinary Medicine, University of California-Davis, San Bernardino, California, USA
| | - Archana Shrestha
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Francisco A Uzal
- California Animal Health and Food Safety Laboratory, San Bernardino Branch, School of Veterinary Medicine, University of California-Davis, San Bernardino, California, USA
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Irudayanathan FJ, Wang X, Wang N, Willsey SR, Seddon IA, Nangia S. Self-Assembly Simulations of Classic Claudins—Insights into the Pore Structure, Selectivity, and Higher Order Complexes. J Phys Chem B 2018; 122:7463-7474. [DOI: 10.1021/acs.jpcb.8b03842] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Xiaoyi Wang
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Nan Wang
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Sarah R. Willsey
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Ian A. Seddon
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Shikha Nangia
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
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Uzal FA, Navarro MA, Li J, Freedman JC, Shrestha A, McClane BA. Comparative pathogenesis of enteric clostridial infections in humans and animals. Anaerobe 2018; 53:11-20. [PMID: 29883627 DOI: 10.1016/j.anaerobe.2018.06.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/03/2018] [Accepted: 06/04/2018] [Indexed: 02/06/2023]
Abstract
Several enteric clostridial diseases can affect humans and animals. Of these, the enteric infections caused by Clostridium perfringens and Clostridium difficile are amongst the most prevalent and they are reviewed here. C. perfringens type A strains encoding alpha toxin (CPA) are frequently associated with enteric disease of many animal mammalian species, but their role in these diseased mammals remains to be clarified. C. perfringens type B encoding CPA, beta (CPB) and epsilon (ETX) toxins causes necro-hemorrhagic enteritis, mostly in sheep, and these strains have been recently suggested to be involved in multiple sclerosis in humans, although evidence of this involvement is lacking. C. perfringens type C strains encode CPA and CPB and cause necrotizing enteritis in humans and animals, while CPA and ETX producing type D strains of C. perfringens produce enterotoxemia in sheep, goats and cattle, but are not known to cause spontaneous disease in humans. The role of C. perfringens type E in animal or human disease remains poorly defined. The newly revised toxinotype F encodes CPA and enterotoxin (CPE), the latter being responsible for food poisoning in humans, and the less prevalent antibiotic associated and sporadic diarrhea. The role of these strains in animal disease has not been fully described and remains controversial. Another newly created toxinotype, G, encodes CPA and necrotic enteritis toxin B-like (NetB), and is responsible for avian necrotic enteritis, but has not been associated with human disease. C. difficile produces colitis and/or enterocolitis in humans and multiple animal species. The main virulence factors of this microorganism are toxins A, B and an ADP-ribosyltransferase (CDT). Other clostridia causing enteric diseases in humans and/or animals are Clostridium spiroforme, Clostridium piliforme, Clostridium colinum, Clostridium sordellii, Clostridium chauvoei, Clostridium septicum, Clostridium botulinum, Clostridium butyricum and Clostridium neonatale. The zoonotic transmission of some, but not all these clostridsial species, has been demonstrated.
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Affiliation(s)
- Francisco A Uzal
- California Animal Health and Food Safety Laboratory System, San Bernardino Branch, University of California, Davis, CA, USA.
| | - Mauricio A Navarro
- California Animal Health and Food Safety Laboratory System, San Bernardino Branch, University of California, Davis, CA, USA
| | - Jihong Li
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - John C Freedman
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Archana Shrestha
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Mechanisms of Action and Cell Death Associated with Clostridium perfringens Toxins. Toxins (Basel) 2018; 10:toxins10050212. [PMID: 29786671 PMCID: PMC5983268 DOI: 10.3390/toxins10050212] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/18/2018] [Accepted: 05/19/2018] [Indexed: 12/26/2022] Open
Abstract
Clostridium perfringens uses its large arsenal of protein toxins to produce histotoxic, neurologic and intestinal infections in humans and animals. The major toxins involved in diseases are alpha (CPA), beta (CPB), epsilon (ETX), iota (ITX), enterotoxin (CPE), and necrotic B-like (NetB) toxins. CPA is the main virulence factor involved in gas gangrene in humans, whereas its role in animal diseases is limited and controversial. CPB is responsible for necrotizing enteritis and enterotoxemia, mostly in neonatal individuals of many animal species, including humans. ETX is the main toxin involved in enterotoxemia of sheep and goats. ITX has been implicated in cases of enteritis in rabbits and other animal species; however, its specific role in causing disease has not been proved. CPE is responsible for human food-poisoning and non-foodborne C. perfringens-mediated diarrhea. NetB is the cause of necrotic enteritis in chickens. In most cases, host–toxin interaction starts on the plasma membrane of target cells via specific receptors, resulting in the activation of intracellular pathways with a variety of effects, commonly including cell death. In general, the molecular mechanisms of cell death associated with C. perfringens toxins involve features of apoptosis, necrosis and/or necroptosis.
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Eichner M, Augustin C, Fromm A, Piontek A, Walther W, Bücker R, Fromm M, Krause G, Schulzke JD, Günzel D, Piontek J. In Colon Epithelia, Clostridium perfringens Enterotoxin Causes Focal Leaks by Targeting Claudins Which are Apically Accessible Due to Tight Junction Derangement. J Infect Dis 2017; 217:147-157. [DOI: 10.1093/infdis/jix485] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 09/12/2017] [Indexed: 12/26/2022] Open
Affiliation(s)
- Miriam Eichner
- Institute of Clinical Physiology, Charité—Universitätsmedizin Berlin, Germany
| | - Christian Augustin
- Institute of Clinical Physiology, Charité—Universitätsmedizin Berlin, Germany
| | - Anja Fromm
- Institute of Clinical Physiology, Charité—Universitätsmedizin Berlin, Germany
| | - Anna Piontek
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | | | - Roland Bücker
- Institute of Clinical Physiology, Charité—Universitätsmedizin Berlin, Germany
| | - Michael Fromm
- Institute of Clinical Physiology, Charité—Universitätsmedizin Berlin, Germany
| | - Gerd Krause
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | | | - Dorothee Günzel
- Institute of Clinical Physiology, Charité—Universitätsmedizin Berlin, Germany
| | - Jörg Piontek
- Institute of Clinical Physiology, Charité—Universitätsmedizin Berlin, Germany
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The Potential Therapeutic Agent Mepacrine Protects Caco-2 Cells against Clostridium perfringens Enterotoxin Action. mSphere 2017; 2:mSphere00352-17. [PMID: 28875177 PMCID: PMC5577654 DOI: 10.1128/msphere.00352-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 08/09/2017] [Indexed: 11/20/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) causes the gastrointestinal (GI) symptoms of a common bacterial food poisoning and several nonfoodborne human GI diseases. A previous study showed that, via an undetermined mechanism, the presence of mepacrine blocks CPE-induced electrophysiologic activity in artificial membranes. The current study now demonstrates that mepacrine also inhibits CPE-induced cytotoxicity in human enterocyte-like Caco-2 cells and that mepacrine does not directly inactivate CPE. Instead, this drug reduces both CPE pore formation and CPE pore activity in Caco-2 cells. These results suggest mepacrine as a therapeutic candidate for treating CPE-mediated GI diseases. Clostridium perfringens enterotoxin (CPE) causes the diarrhea associated with a common bacterial food poisoning and many antibiotic-associated diarrhea cases. The severity of some CPE-mediated disease cases warrants the development of potential therapeutics. A previous study showed that the presence of mepacrine inhibited CPE-induced electrophysiology effects in artificial lipid bilayers lacking CPE receptors. However, that study did not assess whether mepacrine inactivates CPE or, instead, inhibits a step in CPE action. Furthermore, CPE action in host cells is complex, involving the toxin binding to receptors, receptor-bound CPE oligomerizing into a prepore on the membrane surface, and β-hairpins in the CPE prepore inserting into the membrane to form a pore that induces cell death. Therefore, the current study evaluated the ability of mepacrine to protect cells from CPE. This drug was found to reduce CPE-induced cytotoxicity in Caco-2 cells. This protection did not involve mepacrine inactivation of CPE, indicating that mepacrine affects one or more steps in CPE action. Western blotting then demonstrated that mepacrine decreases CPE pore levels in Caco-2 cells. This mepacrine-induced reduction in CPE pore levels did not involve CPE binding inhibition but rather an increase in CPE monomer dissociation due to mepacrine interactions with Caco-2 membranes. In addition, mepacrine was also shown to inhibit CPE pores when already present in Caco-2 cells. These in vitro studies, which identified two mepacrine-sensitive steps in CPE-induced cytotoxicity, add support to further testing of the therapeutic potential of mepacrine against CPE-mediated disease. IMPORTANCEClostridium perfringens enterotoxin (CPE) causes the gastrointestinal (GI) symptoms of a common bacterial food poisoning and several nonfoodborne human GI diseases. A previous study showed that, via an undetermined mechanism, the presence of mepacrine blocks CPE-induced electrophysiologic activity in artificial membranes. The current study now demonstrates that mepacrine also inhibits CPE-induced cytotoxicity in human enterocyte-like Caco-2 cells and that mepacrine does not directly inactivate CPE. Instead, this drug reduces both CPE pore formation and CPE pore activity in Caco-2 cells. These results suggest mepacrine as a therapeutic candidate for treating CPE-mediated GI diseases.
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Abstract
The ability of Clostridium perfringens to form spores plays a key role during the transmission of this Gram-positive bacterium to cause disease. Of particular note, the spores produced by food poisoning strains are often exceptionally resistant to food environment stresses such as heat, cold, and preservatives, which likely facilitates their survival in temperature-abused foods. The exceptional resistance properties of spores made by most type A food poisoning strains and some type C foodborne disease strains involve their production of a variant small acid-soluble protein-4 that binds more tightly to spore DNA than to the small acid-soluble protein-4 made by most other C. perfringens strains. Sporulation and germination by C. perfringens and Bacillus spp. share both similarities and differences. Finally, sporulation is essential for production of C. perfringens enterotoxin, which is responsible for the symptoms of C. perfringens type A food poisoning, the second most common bacterial foodborne disease in the United States. During this foodborne disease, C. perfringens is ingested with food and then, by using sporulation-specific alternate sigma factors, this bacterium sporulates and produces the enterotoxin in the intestines.
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Abstract
Clostridium perfringens enterotoxin (CPE) binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s) from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s) in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease. In susceptible host cells, Clostridium perfringens enterotoxin (CPE) binds to claudin receptors and then forms pores that result in cell death. Using cocultures of CPE receptor-expressing sensitive cells mixed with CPE-insensitive cells lacking receptors for this toxin, the current study determined that CPE-treated sensitive cells release soluble cytotoxic factors, one of which may be a 10- to 30-kDa serine protease, to cause apoptotic death of cells that are themselves CPE insensitive. These findings suggest a novel bystander killing mechanism by which a pore-forming toxin may extend its damage to affect cells not directly responsive to that toxin. If confirmed to occur in vivo by future studies, this bystander killing effect may have significance during CPE-mediated disease and could impact the translational use of CPE for purposes such as cancer therapy.
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Targeting and alteration of tight junctions by bacteria and their virulence factors such as Clostridium perfringens enterotoxin. Pflugers Arch 2016; 469:77-90. [DOI: 10.1007/s00424-016-1902-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/01/2016] [Accepted: 11/06/2016] [Indexed: 01/01/2023]
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Larcombe S, Hutton ML, Lyras D. Involvement of Bacteria Other Than Clostridium difficile in Antibiotic-Associated Diarrhoea. Trends Microbiol 2016; 24:463-476. [DOI: 10.1016/j.tim.2016.02.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/20/2016] [Accepted: 02/01/2016] [Indexed: 02/07/2023]
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Shrestha A, Uzal FA, McClane BA. The interaction of Clostridium perfringens enterotoxin with receptor claudins. Anaerobe 2016; 41:18-26. [PMID: 27090847 DOI: 10.1016/j.anaerobe.2016.04.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/07/2016] [Accepted: 04/15/2016] [Indexed: 01/30/2023]
Abstract
Clostridium perfringens enterotoxin (CPE) has significant medical importance due to its involvement in several common human gastrointestinal diseases. This 35 kDa single polypeptide toxin consists of two domains: a C-terminal domain involved in receptor binding and an N-terminal domain involved in oligomerization, membrane insertion and pore formation. The action of CPE starts with its binding to receptors, which include certain members of the claudin tight junction protein family; bound CPE then forms a series of complexes, one of which is a pore that causes the calcium influx responsible for host cell death. Recent studies have revealed that CPE binding to claudin receptors involves interactions between the C-terminal CPE domain and both the 1st and 2nd extracellular loops (ECL-1 and ECL-2) of claudin receptors. Of particular importance for this binding is the docking of ECL-2 into a pocket present in the C-terminal domain of the toxin. This increased understanding of CPE interactions with claudin receptors is now fostering the development of receptor decoy therapeutics for CPE-mediated gastrointestinal disease, reagents for cancer therapy/diagnoses and enhancers of drug delivery.
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Affiliation(s)
- Archana Shrestha
- 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, USA
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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35
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Clostridium perfringens Enterotoxin: Action, Genetics, and Translational Applications. Toxins (Basel) 2016; 8:toxins8030073. [PMID: 26999202 PMCID: PMC4810218 DOI: 10.3390/toxins8030073] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 03/04/2016] [Accepted: 03/08/2016] [Indexed: 12/21/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) is responsible for causing the gastrointestinal symptoms of several C. perfringens food- and nonfood-borne human gastrointestinal diseases. The enterotoxin gene (cpe) is located on either the chromosome (for most C. perfringens type A food poisoning strains) or large conjugative plasmids (for the remaining type A food poisoning and most, if not all, other CPE-producing strains). In all CPE-positive strains, the cpe gene is strongly associated with insertion sequences that may help to assist its mobilization and spread. During disease, CPE is produced when C. perfringens sporulates in the intestines, a process involving several sporulation-specific alternative sigma factors. The action of CPE starts with its binding to claudin receptors to form a small complex; those small complexes then oligomerize to create a hexameric prepore on the membrane surface. Beta hairpin loops from the CPE molecules in the prepore assemble into a beta barrel that inserts into the membrane to form an active pore that enhances calcium influx, causing cell death. This cell death results in intestinal damage that causes fluid and electrolyte loss. CPE is now being explored for translational applications including cancer therapy/diagnosis, drug delivery, and vaccination.
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Abstract
For suicide gene therapy, initially prodrug-converting enzymes (gene-directed enzyme-producing therapy, GDEPT) were employed to intracellularly metabolize non-toxic prodrugs into toxic compounds, leading to the effective suicidal killing of the transfected tumor cells. In this regard, the suicide gene therapy has demonstrated its potential for efficient tumor eradication. Numerous suicide genes of viral or bacterial origin were isolated, characterized, and extensively tested in vitro and in vivo, demonstrating their therapeutic potential even in clinical trials to treat cancers of different entities. Apart from this, growing efforts are made to generate more targeted and more effective suicide gene systems for cancer gene therapy. In this regard, bacterial toxins are an alternative to the classical GDEPT strategy, which add to the broad spectrum of different suicide approaches. In this context, lytic bacterial toxins, such as streptolysin O (SLO) or the claudin-targeted Clostridium perfringens enterotoxin (CPE) represent attractive new types of suicide oncoleaking genes. They permit as pore-forming proteins rapid and also selective toxicity toward a broad range of cancers. In this chapter, we describe the generation and use of SLO as well as of CPE-based gene therapies for the effective tumor cell eradication as promising, novel suicide gene approach particularly for treatment of therapy refractory tumors.
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Uzal FA, McClane BA, Cheung JK, Theoret J, Garcia JP, Moore RJ, Rood JI. Animal models to study the pathogenesis of human and animal Clostridium perfringens infections. Vet Microbiol 2015; 179:23-33. [PMID: 25770894 DOI: 10.1016/j.vetmic.2015.02.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 02/11/2015] [Accepted: 02/15/2015] [Indexed: 10/23/2022]
Abstract
The most common animal models used to study Clostridium perfringens infections in humans and animals are reviewed here. The classical C. perfringens-mediated histotoxic disease of humans is clostridial myonecrosis or gas gangrene and the use of a mouse myonecrosis model coupled with genetic studies has contributed greatly to our understanding of disease pathogenesis. Similarly, the use of a chicken model has enhanced our understanding of type A-mediated necrotic enteritis in poultry and has led to the identification of NetB as the primary toxin involved in disease. C. perfringens type A food poisoning is a highly prevalent bacterial illness in the USA and elsewhere. Rabbits and mice are the species most commonly used to study the action of enterotoxin, the causative toxin. Other animal models used to study the effect of this toxin are rats, non-human primates, sheep and cattle. In rabbits and mice, CPE produces severe necrosis of the small intestinal epithelium along with fluid accumulation. C. perfringens type D infection has been studied by inoculating epsilon toxin (ETX) intravenously into mice, rats, sheep, goats and cattle, and by intraduodenal inoculation of whole cultures of this microorganism in mice, sheep, goats and cattle. Molecular Koch's postulates have been fulfilled for enterotoxigenic C. perfringens type A in rabbits and mice, for C. perfringens type A necrotic enteritis and gas gangrene in chickens and mice, respectively, for C. perfringens type C in mice, rabbits and goats, and for C. perfringens type D in mice, sheep and goats.
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Affiliation(s)
- Francisco 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.
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Jackie K Cheung
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - James Theoret
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Jorge P Garcia
- Department of Large Animal Medicine, School of Veterinary Medicine, National University of the Center of Buenos Aires Province, Tandil, Argentina
| | - Robert J Moore
- Department of Microbiology, Monash University, Clayton, Victoria, Australia; School of Applied Sciences, RMIT University, Bundoora, Victoria, Australia; Poultry Cooperative Research Centre, Armidale, New South Wales, Australia
| | - Julian I Rood
- Department of Microbiology, Monash University, Clayton, Victoria, Australia; Poultry Cooperative Research Centre, Armidale, New South Wales, Australia
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Freedman JC, Theoret JR, Wisniewski JA, Uzal FA, Rood JI, McClane BA. Clostridium perfringens type A-E toxin plasmids. Res Microbiol 2014; 166:264-79. [PMID: 25283728 DOI: 10.1016/j.resmic.2014.09.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/04/2014] [Accepted: 09/09/2014] [Indexed: 12/26/2022]
Abstract
Clostridium perfringens relies upon plasmid-encoded toxin genes to cause intestinal infections. These toxin genes are associated with insertion sequences that may facilitate their mobilization and transfer, giving rise to new toxin plasmids with common backbones. Most toxin plasmids carry a transfer of clostridial plasmids locus mediating conjugation, which likely explains the presence of similar toxin plasmids in otherwise unrelated C. perfringens strains. The association of many toxin genes with insertion sequences and conjugative plasmids provides virulence flexibility when causing intestinal infections. However, incompatibility issues apparently limit the number of toxin plasmids maintained by a single cell.
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Affiliation(s)
- John C Freedman
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - James R Theoret
- 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
| | - Julian I Rood
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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Yelland TS, Naylor CE, Bagoban T, Savva CG, Moss DS, McClane BA, Blasig IE, Popoff M, Basak AK. Structure of a C. perfringens enterotoxin mutant in complex with a modified Claudin-2 extracellular loop 2. J Mol Biol 2014; 426:3134-3147. [PMID: 25020226 PMCID: PMC10921947 DOI: 10.1016/j.jmb.2014.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/25/2014] [Accepted: 07/07/2014] [Indexed: 12/01/2022]
Abstract
CPE (Clostridium perfringens enterotoxin) is the major virulence determinant for C. perfringens type-A food poisoning, the second most common bacterial food-borne illness in the UK and USA. After binding to its receptors, which include particular human claudins, the toxin forms pores in the cell membrane. The mature pore apparently contains a hexamer of CPE, claudin and, possibly, occludin. The combination of high binding specificity with cytotoxicity has resulted in CPE being investigated, with some success, as a targeted cytotoxic agent for oncotherapy. In this paper, we present the X-ray crystallographic structure of CPE in complex with a peptide derived from extracellular loop 2 of a modified, CPE-binding Claudin-2, together with high-resolution native and pore-formation mutant structures. Our structure provides the first atomic-resolution data on any part of a claudin molecule and reveals that claudin's CPE-binding fingerprint (NPLVP) is in a tight turn conformation and binds, as expected, in CPE's C-terminal claudin-binding groove. The leucine and valine residues insert into the binding groove while the first residue, asparagine, tethers the peptide via an interaction with CPE's aspartate 225 and the two prolines are required to maintain the tight turn conformation. Understanding the structural basis of the contribution these residues make to binding will aid in engineering CPE to target tumor cells.
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Affiliation(s)
- Tamas S Yelland
- Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK
| | - Claire E Naylor
- Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK
| | - Tannya Bagoban
- Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK
| | - Christos G Savva
- Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK
| | - David S Moss
- Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK
| | - Bruce A McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Ingolf E Blasig
- Leibniz-Institut für Molekulare Pharmakologie im Forshungsverbund Berlin e.V. (FMP), 13125 Berlin, Germany
| | - M Popoff
- Anaerobic Bacteria and Toxins Unit, Department of Microbiology, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Ajit K Basak
- Department of Biological Sciences, Birkbeck College, London WC1E 7HX, UK.
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A synthetic peptide corresponding to the extracellular loop 2 region of claudin-4 protects against Clostridium perfringens enterotoxin in vitro and in vivo. Infect Immun 2014; 82:4778-88. [PMID: 25156725 DOI: 10.1128/iai.02453-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) action starts when the toxin binds to claudin receptors. Claudins contain two extracellular loop domains, with the second loop (ECL-2) being slightly smaller than the first. CPE has been shown to bind to ECL-2 in receptor claudins. We recently demonstrated that Caco-2 cells (a naturally CPE-sensitive enterocyte-like cell line) can be protected from CPE-induced cytotoxicity by preincubating the enterotoxin with soluble full-length recombinant claudin-4 (rclaudin-4), which is a CPE receptor, but not with recombinant nonreceptor claudins, such as rclaudin-1. The current study evaluated whether a synthetic peptide corresponding to the claudin-4 ECL-2 sequence can similarly inhibit CPE action in vitro and in vivo. Significant protection of Caco-2 cells was also observed using either rclaudin-4 or the claudin-4 ECL-2 peptide in both a preincubation assay and a coincubation assay. This inhibitory effect was specific, since rclaudin-1 and a synthetic peptide based on the claudin-1 ECL-2 offered no protection to Caco-2 cells. However, the claudin-4 ECL-2 peptide was unable to neutralize cytotoxicity if CPE had already bound to Caco-2 cells. When the study was repeated in vivo using a rabbit small intestinal loop assay, preincubation or coincubation of CPE with the claudin-4 ECL-2 peptide significantly and specifically inhibited the development of CPE-induced luminal fluid accumulation and histologic lesions in rabbit small intestinal loops. No similar in vivo protection from CPE was afforded by the claudin-1 ECL-2 peptide. These results suggest that claudin-4 ECL-2 peptides should be further investigated for their potential therapeutic application against CPE-associated disease.
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Lu RY, Yang WX, Hu YJ. The role of epithelial tight junctions involved in pathogen infections. Mol Biol Rep 2014; 41:6591-610. [PMID: 24965148 DOI: 10.1007/s11033-014-3543-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/20/2014] [Indexed: 12/12/2022]
Abstract
Tight junctions (TJs) are sealing complexes between adjacent epithelial cells, functioning by controlling paracellular passage and maintaining cell polarity. These functions of TJs are primarily based on structural integrity as well as dynamic regulatory balance, indicating plasticity of TJ in response to external stimuli. An indispensable role of TJs involved in pathogen infection has been widely demonstrated since disruption of TJs leads to a distinct increase in paracellular permeability and polarity defects which facilitate viral or bacterial entry and spread. In addition to pathological changes in TJ integrity, TJ proteins such as occludin and claudins can either function as receptors for pathogen entry or interact with viral/bacterial effector molecules as an essential step for characterizing an infective stage. This suggests a more complicated role for TJ itself and especially specific TJ components. Thus, this review surveys the role of the epithelial TJs involved in various pathogen infections, and extends TJ targeted therapeutic and pharmacological application prospects.
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Affiliation(s)
- Ru-Yi Lu
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, 310006, China
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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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Abstract
Clostridium perfringens enterotoxin causes the gastrointestinal (GI) symptoms of C. perfringens type A food poisoning and CPE-associated non-food-borne human GI diseases. It is well established that CPE induces fluid accumulation and severe tissue damage in ligated small intestinal loops of rabbits and other animals. However, a previous study had also reported that CPE binds to rabbit colonic cells yet does not significantly affect rabbit colonic loops. To the contrary, the current study determined that treatment with 50 or 100 μg/ml of CPE causes significant histologic lesions and luminal fluid accumulation in rabbit colonic loops. Interestingly, a CPE-neutralizing monoclonal antibody blocked the development of CPE-induced histologic damage but not luminal fluid accumulation in these loops. Similar luminal fluid accumulation, without significant histologic damage, also occurred after treatment of colonic loops with heat-inactivated CPE, antibody alone, or bovine serum albumin (BSA), indicating that increased osmolarity was causing or contributing to fluid accumulation in CPE-treated colonic loops. Comparative studies revealed the similar development of histologic damage and luminal fluid accumulation in both small intestinal loops and colonic loops after as little as a 1-h treatment with 50 μg/ml of CPE. Consistent with the CPE sensitivity of the small intestine and colon, Western blotting detected CPE binding and large-complex formation in both organs. In addition, Western blotting demonstrated the presence of the high-affinity CPE receptors claudin-3 and -4 in both organs of rabbits, consistent with the observed toxin binding. Collectively, these results offer support for the possible involvement of the colon in CPE-mediated GI disease.
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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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Koval M. Differential pathways of claudin oligomerization and integration into tight junctions. Tissue Barriers 2013; 1:e24518. [PMID: 24665398 PMCID: PMC3867512 DOI: 10.4161/tisb.24518] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 03/30/2013] [Accepted: 04/01/2013] [Indexed: 12/14/2022] Open
Abstract
Tight junctions are the critical intercellular structure required to establish an epithelial barrier. Among the several classes of proteins required to form tight junctions are the tetraspan transmembrane proteins known as claudins that directly determine paracellular permeability. Considerable progress has been made in understanding how incorporation of different claudins into tight junctions increase or decrease paracellular permeability and ion selectivity. However, it has proven difficult to identify discrete steps in claudin assembly and whether claudins exist in distinct oligomerization states prior to tight junction assembly. Studies of homomeric and heteromeric claudin-claudin interactions using complementary techniques suggest a diversity of pathways used by different claudins to oligomerize and integrate into tight junctions.
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Affiliation(s)
- Michael Koval
- Division of Pulmonary Allergy and Critical Care Medicine and Department of Cell Biology; Emory University School of Medicine; Atlanta, GA USA
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Human claudin-8 and -14 are receptors capable of conveying the cytotoxic effects of Clostridium perfringens enterotoxin. mBio 2013; 4:mBio.00594-12. [PMID: 23322640 PMCID: PMC3551551 DOI: 10.1128/mbio.00594-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) contributes to several important human gastrointestinal (GI) diseases. This toxin and its derivatives are also being explored for translational applications, i.e., cancer therapy or drug delivery. Some, but not all, members of the 24-member claudin (Cldn) family of mammalian tight junction proteins can serve as CPE receptors. Among the human Cldns (hCldns), hCldn-3 and -4 are known to convey CPE sensitivity when expressed by fibroblast transfectants. However, other Cldns are also reportedly expressed in the intestines, where they might contribute to natural CPE-mediated GI disease, and in other organs, where they might react with CPE-based therapeutics. Therefore, the current study assessed whether two additional hCldns beside hCldn-3 and -4 are also functional CPE receptors. Using Cldn-expressing transfectants, hCldn-8 and -14 were shown to convey CPE-mediated cytotoxicity at pathophysiologically relevant concentrations of this toxin, although ~2-to-10-fold less efficiently than hCldn-4. Site-directed mutagenesis then demonstrated that the N146 residue in hCldn-14 and the S151 residue in hCldn-8 are largely responsible for modulating the weaker CPE binding properties of hCldn-8 and -14 versus hCldn-4, which broadens understanding of Cldn:CPE binding interactions. Since Cldn-8 and -14 are reportedly expressed in mammalian intestines, the current results support the possibility that these two hCldns contribute to natural CPE-mediated gastrointestinal disease and could be CPE-based therapeutic targets for cancers overexpressing those claudins. However, these results also suggest caution during therapeutic use of CPE, which might trigger toxic side effects in normal human tissues producing hCldn-8 or -14, as well as in those producing hCldn-3 or -4. IMPORTANCE Clostridium perfringens enterotoxin (CPE) is responsible for the gastrointestinal symptoms of the second-most-common bacterial food-borne illness and is also being explored for use as a cancer therapeutic or for increasing drug delivery. Until now, the only known human CPE receptors were claudin-3 and -4. This work shows that human claudin-8 and -14 can also bind CPE and convey cytotoxicity, although slightly less efficiently than claudin-3 and -4. The claudin-8 and -14 residues responsible for this weaker CPE binding were identified, shedding new light on CPE:claudin interactions. Clostridium perfringens enterotoxin (CPE) is responsible for the gastrointestinal symptoms of the second-most-common bacterial food-borne illness and is also being explored for use as a cancer therapeutic or for increasing drug delivery. Until now, the only known human CPE receptors were claudin-3 and -4. This work shows that human claudin-8 and -14 can also bind CPE and convey cytotoxicity, although slightly less efficiently than claudin-3 and -4. The claudin-8 and -14 residues responsible for this weaker CPE binding were identified, shedding new light on CPE:claudin interactions.
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Regulation of Tight Junctions for Therapeutic Advantages. CANCER METASTASIS - BIOLOGY AND TREATMENT 2013. [DOI: 10.1007/978-94-007-6028-8_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Cysteine-scanning mutagenesis supports the importance of Clostridium perfringens enterotoxin amino acids 80 to 106 for membrane insertion and pore formation. Infect Immun 2012; 80:4078-88. [PMID: 22966051 DOI: 10.1128/iai.00069-12] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Clostridium perfringens enterotoxin (CPE) causes the gastrointestinal symptoms of the second most common bacterial food-borne illness. Previous studies suggested that a region named TM1, which has amphipathic characteristics and spans from amino acids 81 to 106 of the native CPE protein, forms a β-hairpin involved in β-barrel pore formation. To further explore the potential role of TM1 in pore formation, the single Cys naturally present in CPE at residue 186 was first altered to alanine by mutagenesis; the resultant rCPE variant, named C186A, was shown to retain cytotoxic properties. Cys-scanning mutagenesis was then performed in which individual Cys mutations were introduced into each TM1 residue of the C186A variant. When those Cys variants were characterized, three variants were identified that exhibit reduced cytotoxicity despite possessing binding and oligomerization abilities similar to those of the C186A variant from which they were derived. Pronase challenge experiments suggested that the reduced cytotoxicity of those two Cys variants, i.e., the F91C and F95C variants, which model to the tip of the β-hairpin, was attributable to a lessened ability of these variants to insert into membranes after oligomerization. In contrast, another Cys variant, i.e., the G103C variant, with impaired cytotoxicity apparently inserted into membranes after oligomerization but could not form a pore with a fully functional channel. Collectively, these results support the TM1 region forming a β-hairpin as an important step in CPE insertion and pore formation. Furthermore, this work identifies the first amino acid residues specifically involved in those two steps in CPE action.
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Uzal FA, McClane BA. Animal models to study the pathogenesis of enterotoxigenic Clostridium perfringens infections. Microbes Infect 2012; 14:1009-16. [PMID: 22713745 DOI: 10.1016/j.micinf.2012.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/05/2012] [Accepted: 06/05/2012] [Indexed: 10/28/2022]
Abstract
Rabbits, mice, rats, non-human primates, sheep and cattle have been used to study the effect of Clostridium perfringens enterotoxin (CPE). CPE produces mostly necrosis of the small intestinal epithelium along with fluid accumulation in rabbits and mice. In the latter, CPE can bind to internal organs such as the liver, which induces lethal potassium levels in blood.
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Affiliation(s)
- Francisco 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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