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Shetty SV, Mazzucco MR, Winokur P, Haigh SV, Rumah KR, Fischetti VA, Vartanian T, Linden JR. Clostridium perfringens Epsilon Toxin Binds to and Kills Primary Human Lymphocytes. Toxins (Basel) 2023; 15:423. [PMID: 37505692 PMCID: PMC10467094 DOI: 10.3390/toxins15070423] [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: 03/31/2023] [Revised: 05/30/2023] [Accepted: 06/07/2023] [Indexed: 07/29/2023] Open
Abstract
Clostridium perfringens epsilon toxin (ETX) is the third most lethal bacterial toxin and has been suggested to be an environmental trigger of multiple sclerosis, an immune-mediated disease of the human central nervous system. However, ETX cytotoxicity on primary human cells has not been investigated. In this article, we demonstrate that ETX preferentially binds to and kills human lymphocytes expressing increased levels of the myelin and lymphocyte protein MAL. Using flow cytometry, ETX binding was determined to be time and dose dependent and was highest for CD4+ cells, followed by CD8+ and then CD19+ cells. Similar results were seen with ETX-induced cytotoxicity. To determine if ETX preference for CD4+ cells was related to MAL expression, MAL gene expression was determined by RT-qPCR. CD4+ cells had the highest amount of Mal gene expression followed by CD8+ and CD19+ cells. These data indicate that primary human cells are susceptible to ETX and support the hypothesis that MAL is a main receptor for ETX. Interestingly, ETX bindings to human lymphocytes suggest that ETX may influence immune response in multiple sclerosis.
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Affiliation(s)
- Samantha V. Shetty
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA (T.V.)
| | - Michael R. Mazzucco
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA (T.V.)
| | - Paige Winokur
- Harold and Margaret Milliken Hatch Laboratory of Neuro-Endocrinology Rockefeller University, New York, NY 10065, USA
| | - Sylvia V. Haigh
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA (T.V.)
| | - Kareem Rashid Rumah
- Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller University, New York, NY 10065, USA
| | - Vincent A. Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller University, New York, NY 10065, USA
| | - Timothy Vartanian
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA (T.V.)
| | - Jennifer R. Linden
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA (T.V.)
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2
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Giannitti F, García JP, Adams V, Armendano JI, Beingesser J, Rood JI, Uzal FA. Experimental acute Clostridium perfringens type D enterotoxemia in sheep is not characterized by specific renal lesions. Vet Pathol 2023:3009858231171669. [PMID: 37177792 DOI: 10.1177/03009858231171669] [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: 05/15/2023]
Abstract
Type D enterotoxemia, caused by Clostridium perfringens epsilon toxin (ETX), is one of the most economically important clostridial diseases of sheep. Acute type D enterotoxemia is characterized by well-documented lesions in the nervous, cardiocirculatory, and pulmonary systems. However, discrepancies and confusion exist as to whether renal lesions are part of the spectrum of lesions of this condition, which is controversial considering that for many decades it has been colloquially referred to as "pulpy kidney disease." Here, the authors assess renal changes in an experimental model of acute type D enterotoxemia in sheep and evaluate the possible role of ETX in their genesis. Four groups of 6 sheep each were intraduodenally inoculated with either a wild-type virulent C. perfringens type D strain, an etx knockout mutant unable to produce ETX, the etx mutant strain complemented with the wild-type etx gene that regains the ETX toxin production, or sterile culture medium (control group). All sheep were autopsied less than 24 hours after inoculation; none of them developed gross lesions in the kidneys. Ten predefined histologic renal changes were scored in each sheep. The proportion of sheep with microscopic changes and their severity scores did not differ significantly between groups. Mild intratubular medullary hemorrhage was observed in only 2 of the 12 sheep inoculated with the wild-type or etx-complemented bacterial strains, but not in the 12 sheep of the other 2 groups. The authors conclude that no specific gross or histologic renal lesions are observed in sheep with experimental acute type D enterotoxemia.
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Affiliation(s)
| | - Jorge P García
- Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil, Buenos Aires, Argentina
| | - Vicki Adams
- Monash University, Parkville, Victoria, Australia
| | - Joaquín I Armendano
- Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil, Buenos Aires, Argentina
| | - Juliann Beingesser
- California Animal Health and Food Safety Laboratoy, University of California at Davis, San Bernardino, CA
| | | | - Francisco A Uzal
- California Animal Health and Food Safety Laboratoy, University of California at Davis, San Bernardino, CA
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3
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Pathology and Pathogenesis of Brain Lesions Produced by Clostridium perfringens Type D Epsilon Toxin. Int J Mol Sci 2022; 23:ijms23169050. [PMID: 36012315 PMCID: PMC9409160 DOI: 10.3390/ijms23169050] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 11/23/2022] Open
Abstract
Clostridium perfringens type D epsilon toxin (ETX) produces severe, and frequently fatal, neurologic disease in ruminant livestock. The disorder is of worldwide distribution and, although vaccination has reduced its prevalence, ETX still causes substantial economic loss in livestock enterprises. The toxin is produced in the intestine as a relatively inactive prototoxin, which is subsequently fully enzymatically activated to ETX. When changed conditions in the intestinal milieu, particularly starch overload, favor rapid proliferation of this clostridial bacterium, large amounts of ETX can be elaborated. When sufficient toxin is absorbed from the intestine into the systemic circulation and reaches the brain, two neurologic syndromes can develop from this enterotoxemia. If the brain is exposed to large amounts of ETX, the lesions are fundamentally vasculocentric. The neurotoxin binds to microvascular endothelial receptors and other brain cells, the resulting damage causing increased vascular permeability and extravasation of plasma protein and abundant fluid into the brain parenchyma. While plasma protein, particularly albumin, pools largely perivascularly, the vasogenic edema becomes widely distributed in the brain, leading to a marked rise in intracranial pressure, coma, sometimes cerebellar herniation, and, eventually, often death. When smaller quantities of ETX are absorbed into the bloodstream, or livestock are partially immune, a more protracted clinical course ensues. The resulting brain injury is characterized by bilaterally symmetrical necrotic foci in certain selectively vulnerable neuroanatomic sites, termed focal symmetrical encephalomalacia. ETX has also been internationally listed as a potential bioterrorism agent. Although there are no confirmed human cases of ETX intoxication, the relatively wide species susceptibility to this toxin and its high toxicity mean it is likely that human populations would also be vulnerable to its neurotoxic actions. While the pathogenesis of ETX toxicity in the brain is incompletely understood, the putative mechanisms involved in neural lesion development are discussed.
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Dorca-Arévalo J, Gómez de Aranda I, Blasi J. New Mutants of Epsilon Toxin from Clostridium perfringens with an Altered Receptor-Binding Site and Cell-Type Specificity. Toxins (Basel) 2022; 14:toxins14040288. [PMID: 35448898 PMCID: PMC9031233 DOI: 10.3390/toxins14040288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 02/01/2023] Open
Abstract
Epsilon toxin (Etx) from Clostridium perfringens is the third most potent toxin after the botulinum and tetanus toxins. Etx is the main agent of enterotoxemia in ruminants and is produced by Clostridium perfringens toxinotypes B and D, causing great economic losses. Etx selectively binds to target cells, oligomerizes and inserts into the plasma membrane, and forms pores. A series of mutants have been previously generated to understand the cellular and molecular mechanisms of the toxin and to obtain valid molecular tools for effective vaccination protocols. Here, two new non-toxic Etx mutants were generated by selective deletions in the binding (Etx-ΔS188-F196) or insertion (Etx-ΔV108-F135) domains of the toxin. As expected, our results showed that Etx-ΔS188-F196 did not exhibit the usual Etx binding pattern but surprisingly recognized specifically an O-glycoprotein present in the proximal tubules of the kidneys in a wide range of animals, including ruminants. Although diminished, Etx-ΔV108-F135 maintained the capacity for binding and even oligomerization, indicating that the mutation particularly affected the pore-forming ability of the toxin.
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Affiliation(s)
- Jonatan Dorca-Arévalo
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, 08907 Barcelona, Spain; (I.G.d.A.); (J.B.)
- Biomedical Research Institute of Bellvitge (IDIBELL), L’Hospitalet de Llobregat, 08908 Barcelona, Spain
- Correspondence:
| | - Inmaculada Gómez de Aranda
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, 08907 Barcelona, Spain; (I.G.d.A.); (J.B.)
| | - Juan Blasi
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, 08907 Barcelona, Spain; (I.G.d.A.); (J.B.)
- Biomedical Research Institute of Bellvitge (IDIBELL), L’Hospitalet de Llobregat, 08908 Barcelona, Spain
- Institute of Neurosciences, University of Barcelona, 08035 Barcelona, Spain
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5
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Zaib S, Khan I. Synthetic and medicinal chemistry of phthalazines: Recent developments, opportunities and challenges. Bioorg Chem 2020; 105:104425. [PMID: 33157344 DOI: 10.1016/j.bioorg.2020.104425] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/22/2020] [Accepted: 10/20/2020] [Indexed: 12/14/2022]
Abstract
Fused diaza-heterocycles constitute the core structure of numerous bioactive natural products and effective therapeutic drugs. Among them, phthalazines have been recognized as remarkable structural leads in medicinal chemistry due to their wide application in pharmaceutical and agrochemical industries. Accessing such challenging pharmaceutical agents/drug candidates with high chemical complexity through synthetically efficient approaches remains an attractive goal in the contemporary medicinal chemistry and drug discovery arena. In this review, we focus on the recent developments in the synthetic routes towards the generation of phthalazine-based active pharmaceutical ingredients and their biological potential against various targets. The general reaction scope of these innovative and easily accessible strategies was emphasized focusing on the functional group tolerance, substrate and coupling partner compatibility/limitation, the choice of catalyst, and product diversification. These processes were also accompanied by the mechanistic insights where deemed appropriate to demonstrate meaningful information. Moreover, the rapid examination of the structure-activity relationship analyses around the phthalazine core enabled by the pharmacophore replacement/integration revealed the generation of robust, efficient, and more selective compounds with pronounced biological effects. A large variety of in silico methods and ADME profiling tools were also employed to provide a global appraisal of the pharmacokinetics profile of diaza-heterocycles. Thus, the discovery of new structural leads offers the promise of improving treatments for various tropical diseases such as tuberculosis, leishmaniasis, malaria, Chagas disease, among many others including various cancers, atherosclerosis, HIV, inflammatory, and cardiovascular diseases. We hope this review would serve as an informative collection of structurally diverse molecules enabling the generation of mature, high-quality, and innovative routes to support the drug discovery endeavors.
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Affiliation(s)
- Sumera Zaib
- Department of Biochemistry, Faculty of Life Sciences, University of Central Punjab, Lahore 54590, Pakistan
| | - Imtiaz Khan
- Department of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom.
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6
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Knapp O, Maier E, Piselli C, Benz R, Hoxha C, Popoff MR. Central residues of the amphipathic β-hairpin loop control the properties of Clostridium perfringens epsilon-toxin channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183364. [PMID: 32450142 DOI: 10.1016/j.bbamem.2020.183364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 05/06/2020] [Accepted: 05/19/2020] [Indexed: 11/27/2022]
Abstract
Clostridium perfringens epsilon toxin (ETX) is a heptameric pore-forming toxin of the aerolysin toxin family. ETX is the most potent toxin of this toxin family and the third most potent bacterial toxin with high cytotoxic and lethal activities in animals. In addition, ETX shows a demyelinating activity in nervous tissue leading to devastating multifocal central nervous system white matter disease in ruminant animals. Pore formation in target cell membrane is most likely the initial critical step in ETX biological activity. Eight single to quadruple ETX mutants were generated by replacement of polar residues (serine, threonine, glutamine) in middle positions of the β-strands forming the β-barrel and facing the channel lumen with charged glutamic residues. Channel activity and ion selectivity were monitored in artificial lipid monolayer membranes and cytotoxicity was investigated in MDCK cells by the viability MTT test and propidium iodide entry. All the mutants formed channels with similar conductance in artificial lipid membranes and increasing cation selectivity for increasing number of mutations. Here, we show that residues in the central position of each β-strand of the amphipathic β-hairpin loop that forms the transmembrane pore, control the size and ion selectivity of the channel. While the highest cationic ETX mutants were not cytotoxic, no strict correlation was observed between ion selectivity and cytotoxicity.
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Affiliation(s)
- Oliver Knapp
- Institut Pasteur, Bacterial Toxins, 28 rue du Dr Roux, 75724 Paris cedex 15, France
| | - Elke Maier
- Rudolf-Virchow-Center for Experimental Biomedicine, Versbacher Str. 9, 97078 Würzburg, Germany
| | - Claudio Piselli
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Roland Benz
- Rudolf-Virchow-Center for Experimental Biomedicine, Versbacher Str. 9, 97078 Würzburg, Germany; Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Cezarela Hoxha
- Institut Pasteur, Bacterial Toxins, 28 rue du Dr Roux, 75724 Paris cedex 15, France
| | - Michel R Popoff
- Institut Pasteur, Bacterial Toxins, 28 rue du Dr Roux, 75724 Paris cedex 15, France.
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Etx-Y71A as a non-toxic mutant of Clostridium perfringens epsilon toxin induces protective immunity in mice and sheep. Vaccine 2020; 38:6553-6561. [PMID: 32788135 DOI: 10.1016/j.vaccine.2020.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/25/2020] [Accepted: 08/03/2020] [Indexed: 11/21/2022]
Abstract
Epsilon toxin (Etx) is an extremely potent toxin produced by Clostridium perfringens toxinotypes B and D, which cause fatal enterotoxemia in many livestock species, mainly sheep and goats. Our previous study demonstrated that the aromatic amino acid (AA) residue at position 71 in domain III of Etx is needed for its cytotoxic activity toward MDCK cells. Here, we first determined that Etx mutants with non-aromatic AA substitutions at Tyr71 lost lethality in mice, indicating that the aromatic AA residue at position 71 is a toxicity determinant of Etx in vivo. After intravenous injection with a high dose of the trypsin-activated Etx-Y71A mutant, mice did not show any histopathological lesions, and confocal microscopy observations further showed that Etx-Y71A lost the ability to cross the blood-brain barrier of the mice. These results suggested that the Etx-Y71A mutant is sufficiently safe in vivo to be a vaccine candidate. Furthermore, the immune efficacy of Etx-Y71A was evaluated in model and host animals. Mice inoculated with this mutant produced high levels of neutralizing antibodies and were completely protected from a 100 LD50 of trypsin-activated Etx challenge. Sheep immunized with Etx-Y71A produced high levels of neutralizing antibodies that provided protection in mice against an activated Etx challenge, and lambs could receive passive immunity through immunization of pregnant ewes. Additionally, homology modeling and circular dichroism analysis showed that Etx-Y71A has structural similarity to Etx, which provides a structural basis for Etx-Y71A retaining the immunogenicity of Etx. Taken together, these results suggest that Etx-Y71A is a potential vaccine candidate against Etx-inducing enterotoxemia.
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8
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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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9
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Dorca-Arévalo J, Dorca E, Torrejón-Escribano B, Blanch M, Martín-Satué M, Blasi J. Lung endothelial cells are sensitive to epsilon toxin from Clostridium perfringens. Vet Res 2020; 51:27. [PMID: 32093740 PMCID: PMC7041264 DOI: 10.1186/s13567-020-00748-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/22/2020] [Indexed: 11/12/2022] Open
Abstract
The pore-forming protein epsilon toxin (Etx) from Clostridium perfringens produces acute perivascular edema affecting several organs, especially the brain and lungs. Despite the toxin evident effect on microvasculature and endothelial cells, the underlying molecular and cellular mechanisms remain obscure. Moreover, no Etx-sensitive endothelial cell model has been identified to date. Here, we characterize the mouse lung endothelial cell line 1G11 as an Etx-sensitive cell line and compare it with the well-characterized Etx-sensitive Madin-Darby canine kidney epithelial cell line. Several experimental approaches, including morphological and cytotoxic assays, clearly demonstrate that the 1G11 cell line is highly sensitive to Etx and show the specific binding, oligomerization, and pore-forming activity of the toxin in these cells. Recently, the myelin and lymphocyte (MAL) protein has been postulated as a putative receptor for Etx. Here, we show the presence of Mal mRNA in the 1G11 cell line and the presence of the MAL protein in the endothelium of some mouse lung vessels, supporting the hypothesis that this protein is a key element in the Etx intoxication pathway. The existence of an Etx-sensitive cell line of endothelial origin would help shed light on the cellular and molecular mechanisms underlying Etx-induced edema and its consequences.
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Affiliation(s)
- Jonatan Dorca-Arévalo
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain. .,Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain. .,Institute of Neurosciences, University of Barcelona, 08035, Barcelona, Spain.
| | - Eduard Dorca
- Pathology Service, Bellvitge University Hospital, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Benjamín Torrejón-Escribano
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain.,Centres Científics i Tecnològics, Universitat de Barcelona, Campus Bellvitge, Barcelona, Spain
| | - Marta Blanch
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain.,Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, 08035, Barcelona, Spain
| | - Mireia Martín-Satué
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain.,Biomedical Research Institute of Bellvitge (IDIBELL), Oncobell Program, CIBERONC, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Juan Blasi
- Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain.,Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, 08035, Barcelona, Spain
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10
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Assessing the bioactivity of the codon optimized sfGFP-IGF1 fusion protein via interaction with IGFBP3 and induction of cell proliferation. GENE REPORTS 2019. [DOI: 10.1016/j.genrep.2019.100496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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11
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Linden JR, Flores C, Schmidt EF, Uzal FA, Michel AO, Valenzuela M, Dobrow S, Vartanian T. Clostridium perfringens epsilon toxin induces blood brain barrier permeability via caveolae-dependent transcytosis and requires expression of MAL. PLoS Pathog 2019; 15:e1008014. [PMID: 31703116 PMCID: PMC6867657 DOI: 10.1371/journal.ppat.1008014] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 11/20/2019] [Accepted: 08/01/2019] [Indexed: 12/13/2022] Open
Abstract
Clostridium perfringens epsilon toxin (ETX) is responsible for causing the economically devastating disease, enterotoxaemia, in livestock. It is well accepted that ETX causes blood brain barrier (BBB) permeability, however the mechanisms involved in this process are not well understood. Using in vivo and in vitro methods, we determined that ETX causes BBB permeability in mice by increasing caveolae-dependent transcytosis in brain endothelial cells. When mice are intravenously injected with ETX, robust ETX binding is observed in the microvasculature of the central nervous system (CNS) with limited to no binding observed in the vasculature of peripheral organs, indicating that ETX specifically targets CNS endothelial cells. ETX binding to CNS microvasculature is dependent on MAL expression, as ETX binding to CNS microvasculature of MAL-deficient mice was not detected. ETX treatment also induces extravasation of molecular tracers including 376Da fluorescein salt, 60kDA serum albumin, 70kDa dextran, and 155kDA IgG. Importantly, ETX-induced BBB permeability requires expression of both MAL and caveolin-1, as mice deficient in MAL or caveolin-1 did not exhibit ETX-induced BBB permeability. Examination of primary murine brain endothelial cells revealed an increase in caveolae in ETX-treated cells, resulting in dynamin and lipid raft-dependent vacuolation without cell death. ETX-treatment also results in a rapid loss of EEA1 positive early endosomes and accumulation of large, RAB7-positive late endosomes and multivesicular bodies. Based on these results, we hypothesize that ETX binds to MAL on the apical surface of brain endothelial cells, causing recruitment of caveolin-1, triggering caveolae formation and internalization. Internalized caveolae fuse with early endosomes which traffic to late endosomes and multivesicular bodies. We believe that these multivesicular bodies fuse basally, releasing their contents into the brain parenchyma. Clostridium perfringens epsilon toxin (ETX) is an extremely lethal bacterial toxin known to cause a devastating disease in livestock animals and may be a possible cause of multiple sclerosis in humans. ETX is well known to cause disruption of the blood-brain barrier (BBB), a critical structure necessary for proper brain function. Deterioration of this barrier allows entry of toxic blood-borne material to enter the brain. Although ETX-induced BBB dysfunction is well accepted, how this happens is unknown. Here, we demonstrate that ETX causes BBB permeability by inducing formation of cell-surface invaginations called caveolae in endothelial cells, the cells that line blood vessels. Importantly, only endothelial cells from the brain and other central nervous system organs appear to be a target of ETX, as the toxin only binds to blood vessels in these organs and not blood vessels from other organs. These ETX-induced caveolae fuse with other caveolae and specialized intracellular vesicles called endosomes. We predict that these endosomes engulf blood-borne material during their internalization, allowing material to travel from the blood, through the cell, and into brain tissue. We also show that expression of the protein MAL and caveolin-1 is necessary for ETX-induced BBB permeability.
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Affiliation(s)
- Jennifer R. Linden
- The Brain and Mind Research Institute and the Department of Neurology, Weill Cornell Medical College, New York, New York, United States of America
| | - Claudia Flores
- The Brain and Mind Research Institute and the Department of Neurology, Weill Cornell Medical College, New York, New York, United States of America
| | - Eric F. Schmidt
- Laboratory of Molecular Biology, The Rockefeller University, New York, New York, United States of America
| | - Francisco A. Uzal
- California Animal Health & Food Safety Laboratory System, San Bernardino Branch, University of California, Davis, San Bernardino, California, United States of America
| | - Adam O. Michel
- Laboratory of Comparative Pathology, Center of Comparative Medicine and Pathology, Memorial Sloan Kettering Cancer Center, The Rockefeller University, Weill Cornell Medicine, New York, New York, United States of America
| | - Marissa Valenzuela
- The Brain and Mind Research Institute and the Department of Neurology, Weill Cornell Medical College, New York, New York, United States of America
| | - Sebastian Dobrow
- The Brain and Mind Research Institute and the Department of Neurology, Weill Cornell Medical College, New York, New York, United States of America
| | - Timothy Vartanian
- The Brain and Mind Research Institute and the Department of Neurology, Weill Cornell Medical College, New York, New York, United States of America
- * E-mail:
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12
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Gil C, Dorca-Arévalo J, Blasi J. Calcium enhances binding of Clostridium perfringens epsilon toxin to sulfatide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:161-169. [PMID: 30463699 DOI: 10.1016/j.bbamem.2018.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/20/2018] [Accepted: 08/07/2018] [Indexed: 01/07/2023]
Abstract
Epsilon toxin (Etx) from Clostridium perfringens is synthesized as a very low-active prototoxin form (proEtx) that becomes active upon proteolytic activation and has the capacity to cross the blood-brain barrier (BBB), thereby producing severe neurological effects. The identity and requirements of host receptors of Etx remain a matter of controversy. In the present study, we analysed the binding of proEtx or Etx to liposomes containing distearoylphosphatidylcholine (DSPC), cholesterol and sulfatide, or alternatively to detergent-solubilized lipids, using surface plasmon resonance (SPR). We also tested the influence of calcium on Etx or proEtx binding. Our findings show that the presence of sulfatide in liposomes increases both Etx and proEtx binding, and Etx binding is enhanced by calcium. These results were corroborated when SPR was conducted with immobilized toxin, since detergent-solubilized sulfatide increases its binding to Etx in the presence of calcium, but not to proEtx. Moreover, binding affinity is also affected, since the treatment of liposomes with sulfatase causes the dissociation rate constants (KD) in both proEtx and Etx to increase, especially in the case of proEtx in the presence of calcium. In addition, protein-lipid overlay assays corroborated the calcium-induced enhancement of Etx binding to sulfatide, and to lipids extracted from sulfatide-enriched rat brain lipid rafts. In conclusion, the present work highlights the role of sulfatide as an important element in the pathophysiology of Etx and reveals the influence of calcium in the interaction of Etx, but not of proEtx, with the target membrane.
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Affiliation(s)
- C Gil
- Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Catalunya, Spain.
| | - J Dorca-Arévalo
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain; Institut de Neurociències, Universitat de Barcelona, Spain
| | - J Blasi
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain; Institut de Neurociències, Universitat de Barcelona, Spain
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13
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Kaushik H, Dixit A, Garg LC. Synthesis of peptide based epsilon toxin vaccine by covalent anchoring to tetanus toxoid. Anaerobe 2018; 53:50-55. [DOI: 10.1016/j.anaerobe.2018.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/12/2018] [Accepted: 06/15/2018] [Indexed: 02/08/2023]
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14
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The Cytotoxicity of Epsilon Toxin from Clostridium perfringens on Lymphocytes Is Mediated by MAL Protein Expression. Mol Cell Biol 2018; 38:MCB.00086-18. [PMID: 29987189 DOI: 10.1128/mcb.00086-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/29/2018] [Indexed: 01/07/2023] Open
Abstract
Epsilon toxin (Etx) from Clostridium perfringens is a pore-forming protein that crosses the blood-brain barrier, binds to myelin, and, hence, has been suggested to be a putative agent for the onset of multiple sclerosis, a demyelinating neuroinflammatory disease. Recently, myelin and lymphocyte (MAL) protein has been identified to be a key protein in the cytotoxic effect of Etx; however, the association of Etx with the immune system remains a central question. Here, we show that Etx selectively recognizes and kills only human cell lines expressing MAL protein through a direct Etx-MAL protein interaction. Experiments on lymphocytic cell lines revealed that MAL protein-expressing T cells, but not B cells, are sensitive to Etx and reveal that the toxin may be used as a molecular tool to distinguish subpopulations of lymphocytes. The overall results open the door to investigation of the role of Etx and Clostridium perfringens on inflammatory and autoimmune diseases like multiple sclerosis.
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Dorca-Arévalo J, Blanch M, Pradas M, Blasi J. Epsilon toxin from Clostridium perfringens induces cytotoxicity in FRT thyroid epithelial cells. Anaerobe 2018; 53:43-49. [PMID: 29895394 DOI: 10.1016/j.anaerobe.2018.05.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/25/2018] [Accepted: 05/26/2018] [Indexed: 12/24/2022]
Abstract
Epsilon toxin (Etx) is produced by Clostridium perfringens and induces enterotoxemia in ruminants. Etx crosses the blood-brain barrier, binds to myelin structures, and kills oligodendrocytes, inducing central nervous system demyelination. In addition, Etx has a cytotoxic effect on distal and collecting kidney tubules. There are few cell lines sensitive to Etx. At present, the most sensitive in vitro model for Etx is the Madin-Darby canine kidney (MDCK) cell line, where Etx oligomerizes and forms a pore with consequent ion efflux and cell death. Although the Etx receptor has not yet been fully clarified, it is known that caveolin 1 and 2 potentiate Etx cytotoxicity and oligomerization, and more recently, the myelin and lymphocyte (MAL) protein has been implicated in Etx binding and activity. Here, we studied the effect of Etx on Fischer rat thyroid cells (FRT) and observed similar effects as those seen in MDCK cells. Etx incubated with FRT cells showed binding to the plasma membrane, and western blotting assays revealed oligomeric complex formation. Moreover, cytotoxic assays on FRT cells after Etx incubation indicated cell death at a similar level as in MDCK cells. In addition, a luminescent ATP detection assay revealed ATP depletion in FRT cells after Etx exposure. Previous studies have reported that FRT cells do not express caveolins and do not form caveolae but express MAL protein in glycolipid-enriched membrane microdomains. Our results indicate that caveolins are not directly implicated in Etx cytotoxicity, supporting the notion that the MAL protein is involved in Etx action. In addition, a cell line of thyroid origin is described for the first time as a good model to study Etx action.
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Affiliation(s)
- Jonatan Dorca-Arévalo
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, 08907, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), Hospitalet de Llobregat, Barcelona, 08907, Spain; Institut de Neurociències, Universitat de Barcelona, Barcelona 08035, Spain
| | - Marta Blanch
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, 08907, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), Hospitalet de Llobregat, Barcelona, 08907, Spain; Institut de Neurociències, Universitat de Barcelona, Barcelona 08035, Spain
| | - Marina Pradas
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, 08907, Spain
| | - Juan Blasi
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, Campus of Bellvitge, University of Barcelona, Hospitalet de Llobregat, Barcelona, 08907, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), Hospitalet de Llobregat, Barcelona, 08907, Spain; Institut de Neurociències, Universitat de Barcelona, Barcelona 08035, Spain.
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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: 112] [Impact Index Per Article: 18.7] [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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Acute Effect of Pore-Forming Clostridium perfringens ε-Toxin on Compound Action Potentials of Optic Nerve of Mouse. eNeuro 2017; 4:eN-NWR-0051-17. [PMID: 28798954 PMCID: PMC5550839 DOI: 10.1523/eneuro.0051-17.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/31/2017] [Accepted: 06/16/2017] [Indexed: 11/21/2022] Open
Abstract
ε-Toxin is a pore forming toxin produced by Clostridium perfringens types B and D. It is synthesized as a less active prototoxin form that becomes fully active upon proteolytic activation. The toxin produces highly lethal enterotoxaemia in ruminants, has the ability to cross the blood–brain barrier (BBB) and specifically binds to myelinated fibers. We discovered that the toxin induced a release of ATP from isolated mice optic nerves, which are composed of myelinated fibers that are extended from the central nervous system. We also investigated the effect of the toxin on compound action potentials (CAPs) in isolated mice optic nerves. When nerves were stimulated at 100 Hz during 200 ms, the decrease of the amplitude and the area of the CAPs was attenuated in the presence of ε-toxin. The computational modelling of myelinated fibers of mouse optic nerve revealed that the experimental results can be mimicked by an increase of the conductance of myelin and agrees with the pore forming activity of the toxin which binds to myelin and could drill it by making pores. The intimate ultrastructure of myelin was not modified during the periods of time investigated. In summary, the acute action of the toxin produces a subtle functional impact on the propagation of the nerve action potential in myelinated fibers of the central nervous system with an eventual desynchronization of the information. These results may agree with the hypothesis that the toxin could be an environmental trigger of multiple sclerosis (MS).
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18
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Abbady AQ, Twair A, Ali B, Murad H. Characterization of Annexin V Fusion with the Superfolder GFP in Liposomes Binding and Apoptosis Detection. Front Physiol 2017; 8:317. [PMID: 28579961 PMCID: PMC5437369 DOI: 10.3389/fphys.2017.00317] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/02/2017] [Indexed: 12/29/2022] Open
Abstract
Programed cell death is a critical and unavoidable part of life. One of the most widely used markers for dying cells, by apoptosis or pyroptosis, is the redistribution of phosphatidylserine (PS) from the inner to the outer plasma membrane leaflet. Annexin V protein is a sensitive and specific probe to mark this event because of its high affinity to the exposed PS. Beyond that, annexin V can bind to any PS-containing phospholipid bilayer of almost all tiny forms of membranous vesicles like blood platelets, exosomes, or even nanostructured liposomes. In this work, recombinant human annexin V was produced as a fusion with a highly fluorescent superfolder derivative of the green fluorescent protein (sfGFP) in Escherichia coli. The fusion protein(sfGFP-ANXV, 64 kDa), annexin V (ANXV, 40 kDa), and sfGFP (27 kDa) were separately produced after cloning their encoding genes in pRSET plasmid, and all proteins were expressed in a soluble form, then purified in high yields because of their N-terminal 6× His tag (~150 mg of pure protein per 1 L culture). Superiority of this fluorescent fusion protein over fluorescein-conjugated annexin V was demonstrated in binding to phospholipids (and their liposomes), prepared from natural sources (soya bean and egg yolk) that have different content of PS, by using different methods including ELISA, dot-blotting, surface plasmon resonance, and flow cytometry. We also applied fluorescent annexin V in the detection of apoptotic cells by flow cytometry and fluorescent microscopy. Interestingly, sfGFP-ANXV fusion was more sensitive to early apoptotic stressed HeLa cells than fluorescein-conjugated-ANXV. This highly expressed and functional sfGFP-ANXV fusion protein provides a promising ready-to-use molecular tool for quantifying liposomes (or similarly exosomes) and detecting apoptosis in cells.
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Affiliation(s)
- Abdul Qader Abbady
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of SyriaDamascus, Syria
| | - Aya Twair
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of SyriaDamascus, Syria.,Department of Animal Biology, Faculty of Sciences, Damascus UniversityDamascus, Syria
| | - Bouthaina Ali
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of SyriaDamascus, Syria
| | - Hossam Murad
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of SyriaDamascus, Syria
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Kang J, Gao J, Yao W, Kang L, Gao S, Yang H, Ji B, Li P, Liu J, Yao J, Xin W, Zhao B, Wang J. F199E substitution reduced toxicity of Clostridium perfringens epsilon toxin by depriving the receptor binding capability. Hum Vaccin Immunother 2017; 13:1598-1608. [PMID: 28304231 DOI: 10.1080/21645515.2017.1303022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epsilon toxin (ETX), a potent toxin, is produced by types B and D strains of Clostridium perfringens, which could cause severe diseases in humans and domestic animals. Mutant rETXF199E was previously demonstrated to be a good vaccine candidate. However, the mechanism concerned remains unknown. To clarify how F199E substitution reduced ETX toxicity, we performed a series of experiments. The results showed that the cell-binding and pore-forming ability of rETXF199E was almost abolished. We speculated that F199E substitution reduced toxicity by depriving the receptor binding capability of ETX, which contributed to the hypothesis that domain I of ETX is responsible for cell binding. In addition, our data suggested that ETX could cause Ca2+ release from intracellular Ca2+ stores, which may underlie an alternate pathway leading to cell death. Furthermore, ETX induced crenation of the MDCK cells was observed, with sags and crests first appearing on the surface of condensed MDCK cells, according to scanning electron microscopy. The data also demonstrated the safety and potentiality of rETXF199E as a vaccine candidate for humans. In summary, findings of this work potentially contribute to a better understanding of the pathogenic mechanism of ETX and the development of vaccine against diseases caused by ETX, using mutant proteins.
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Affiliation(s)
- Jingjing Kang
- a Life Science Institute of Hebei Normal University , Shijiazhuang, Hebei Province , PR China
| | - Jie Gao
- a Life Science Institute of Hebei Normal University , Shijiazhuang, Hebei Province , PR China
| | - Wenwu Yao
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Lin Kang
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Shan Gao
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Hao Yang
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Bin Ji
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Ping Li
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Jing Liu
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Jiahao Yao
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Wenwen Xin
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
| | - Baohua Zhao
- a Life Science Institute of Hebei Normal University , Shijiazhuang, Hebei Province , PR China
| | - Jinglin Wang
- b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China
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20
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Liu J, Yang H, Yin Z, Jiang X, Zhong H, Qiu D, Zhu F, Li R. Remodeling of the gut microbiota and structural shifts in Preeclampsia patients in South China. Eur J Clin Microbiol Infect Dis 2016; 36:713-719. [PMID: 27988814 DOI: 10.1007/s10096-016-2853-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 11/22/2016] [Indexed: 12/13/2022]
Abstract
Preeclampsia (PE) is one of the pregnancy metabolic diseases. Since Gut microbiota play important roles in the hosts' metabolism, it is necessary to investigate the gut microbiota in PE patients, so that some intestinal dysbiosis might be detected as a biomarker for PE early diagnosis or as a target for intervention. One hundred subjects were categorized into four groups: 26 PE patients in late pregnancy, healthy individuals in early, middle, and late pregnancy (26/24/24 women). Gut microbiota were analyzed by sequencing the V4 region of the 16S rDNA gene using Illuminal MiSeq. Data were analyzed by multivariate statistics. Bacteroidetes was the dominant bacterium (47.57-52.35%) in the pregnant women in South China. Tenericutes increased while Verrucomicrobia almost disappeared in late pregnancy. In the PE patients, there was an overall increase in pathogenic bacteria, Clostridium perfringens (p = 0.03) and Bulleidia moorei (p = 0.00) but a reduction in probiotic bacteria Coprococcus catus (p = 0.03). Our research suggests that there is a significant structural shift of the gut microbiota in PE patients, which might be associated with the occurrence and development of the disease. However, further studies are required to understand the underlying mechanisms.
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Affiliation(s)
- J Liu
- The First Affiliate Hospital of Jinan University, Guangzhou, 510630, China
| | - H Yang
- Biomedical Translational Research Institute of Jinan University, Guangzhou, 510632, China
| | - Z Yin
- Biomedical Translational Research Institute of Jinan University, Guangzhou, 510632, China
| | - X Jiang
- Computer College of Central China Normal University, Wuhan, 430000, China
| | - H Zhong
- Biomedical Translational Research Institute of Jinan University, Guangzhou, 510632, China
| | - D Qiu
- The First Affiliate Hospital of Jinan University, Guangzhou, 510630, China
| | - F Zhu
- The First Affiliate Hospital of Jinan University, Guangzhou, 510630, China
| | - R Li
- The First Affiliate Hospital of Jinan University, Guangzhou, 510630, China.
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21
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Anusha S, Sinha A, Babu Rajeev CP, Chu TTT, Mathai J, Ximei H, Fuchs JE, Shivananju N, Bender A, Preiser PR, Rangappa KS, Basappa, Chandramohanadas R. Synthesis, characterization and in vitro evaluation of novel enantiomerically-pure sulphonamide antimalarials. Org Biomol Chem 2016; 13:10681-90. [PMID: 26347024 DOI: 10.1039/c5ob01479d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Malaria parasites are currently gaining drug-resistance rapidly, across countries and continents. Hence, the discovery and development of novel chemical scaffolds, with superior antimalarial activity remain an important priority, for the developing world. Our report describes the development, characterization and evaluation of novel bepotastine-based sulphonamide antimalarials inhibiting asexual stage development of Plasmodium falciparum parasites in vitro. The screening results showed potent inhibitory activity of a number of novel sulphonamides against P. falciparum at low micromolar concentrations, in particular in late-stage parasite development. Based on computational studies we hypothesize N-myristoyltransferase as the target of the compounds developed here. Our results demonstrate the value of novel bepotastine-based sulphonamide compounds for targeting the asexual developmental stages of P. falciparum.
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Affiliation(s)
- Sebastian Anusha
- Laboratory of Chemical Biology, Department of Chemistry, Bangalore University, Bangalore, India.
| | - Ameya Sinha
- Pillar of Engineering Product Development, Singapore University of Technology & Design, Singapore.
| | - C P Babu Rajeev
- Laboratory of Chemical Biology, Department of Chemistry, Bangalore University, Bangalore, India.
| | - Trang T T Chu
- Pillar of Engineering Product Development, Singapore University of Technology & Design, Singapore.
| | - Jessin Mathai
- Gulf Medical University, Ajman, United Arab Emirates
| | - Huang Ximei
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Julian E Fuchs
- Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK and Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 82, 6020 Innsbruck, Austria
| | | | - Andreas Bender
- Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK
| | | | | | - Basappa
- Laboratory of Chemical Biology, Department of Chemistry, Bangalore University, Bangalore, India.
| | - Rajesh Chandramohanadas
- Pillar of Engineering Product Development, Singapore University of Technology & Design, Singapore.
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Subramanian G, Babu Rajeev CP, Mohan CD, Sinha A, Chu TTT, Anusha S, Ximei H, Fuchs JE, Bender A, Rangappa KS, Chandramohanadas R, Basappa. Synthesis and in vitro evaluation of hydrazinyl phthalazines against malaria parasite, Plasmodium falciparum. Bioorg Med Chem Lett 2016; 26:3300-3306. [PMID: 27261180 DOI: 10.1016/j.bmcl.2016.05.049] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/05/2016] [Accepted: 05/18/2016] [Indexed: 10/21/2022]
Abstract
In this report, we describe the synthesis of 1-(Phthalazin-4-yl)-hydrazine using bronsted acidic ionic liquids and demonstrate their ability to inhibit asexual stage development of human malaria parasite, Plasmodium falciparum. Through computational studies, we short-listed chemical scaffolds with potential binding affinity to an essential parasite protein, dihydroorotate dehydrogenase (DHODH). Further, these compounds were synthesized in the lab and tested against P. falciparum. Several compounds from our library showed inhibitory activity at low micro-molar concentrations with minimal cytotoxic effects. These results indicate the potential of hydralazine derivatives as reference scaffolds to develop novel antimalarials.
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Affiliation(s)
- Gowtham Subramanian
- Pillar of Engineering Product Development, Singapore University of Technology & Design, Singapore 487372, Singapore
| | - C P Babu Rajeev
- Laboratory of Chemical Biology, Department of Chemistry, Bangalore University, Central College Campus, Palace Road, Bangalore 560001, India
| | | | - Ameya Sinha
- Pillar of Engineering Product Development, Singapore University of Technology & Design, Singapore 487372, Singapore
| | - Trang T T Chu
- Pillar of Engineering Product Development, Singapore University of Technology & Design, Singapore 487372, Singapore
| | - Sebastian Anusha
- Laboratory of Chemical Biology, Department of Chemistry, Bangalore University, Central College Campus, Palace Road, Bangalore 560001, India
| | - Huang Ximei
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Julian E Fuchs
- Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW Cambridge, UK; Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 82, 6020 Innsbruck, Austria
| | - Andreas Bender
- Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW Cambridge, UK
| | | | - Rajesh Chandramohanadas
- Pillar of Engineering Product Development, Singapore University of Technology & Design, Singapore 487372, Singapore.
| | - Basappa
- Laboratory of Chemical Biology, Department of Chemistry, Bangalore University, Central College Campus, Palace Road, Bangalore 560001, India.
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Bokori-Brown M, Petrov PG, Khafaji MA, Mughal MK, Naylor CE, Shore AC, Gooding KM, Casanova F, Mitchell TJ, Titball RW, Winlove CP. Red Blood Cell Susceptibility to Pneumolysin: CORRELATION WITH MEMBRANE BIOCHEMICAL AND PHYSICAL PROPERTIES. J Biol Chem 2016; 291:10210-27. [PMID: 26984406 DOI: 10.1074/jbc.m115.691899] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Indexed: 12/20/2022] Open
Abstract
This study investigated the effect of the biochemical and biophysical properties of the plasma membrane as well as membrane morphology on the susceptibility of human red blood cells to the cholesterol-dependent cytolysin pneumolysin, a key virulence factor of Streptococcus pneumoniae, using single cell studies. We show a correlation between the physical properties of the membrane (bending rigidity and surface and dipole electrostatic potentials) and the susceptibility of red blood cells to pneumolysin-induced hemolysis. We demonstrate that biochemical modifications of the membrane induced by oxidative stress, lipid scrambling, and artificial cell aging modulate the cell response to the toxin. We provide evidence that the diversity of response to pneumolysin in diabetic red blood cells correlates with levels of glycated hemoglobin and that the mechanical properties of the red blood cell plasma membrane are altered in diabetes. Finally, we show that diabetic red blood cells are more resistant to pneumolysin and the related toxin perfringolysin O relative to healthy red blood cells. Taken together, these studies indicate that the diversity of cell response to pneumolysin within a population of human red blood cells is influenced by the biophysical and biochemical status of the plasma membrane and the chemical and/or oxidative stress pre-history of the cell.
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Affiliation(s)
- Monika Bokori-Brown
- From the College of Life and Environmental Sciences, School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom,
| | - Peter G Petrov
- the College of Engineering, Mathematics and Physical Sciences, School of Physics, University of Exeter, Exeter EX4 4QL, United Kingdom
| | - Mawya A Khafaji
- the College of Engineering, Mathematics and Physical Sciences, School of Physics, University of Exeter, Exeter EX4 4QL, United Kingdom
| | - Muhammad K Mughal
- the Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Claire E Naylor
- the Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
| | - Angela C Shore
- the Department of Diabetes and Vascular Medicine, University of Exeter Medical School, Barrack Road, Exeter EX2 5AX, United Kingdom, the National Institute for Health Research Exeter Clinical Research Facility, Royal Devon and Exeter National Health Service Foundation Trust, Exeter EX2 5DW, United Kingdom, and
| | - Kim M Gooding
- the Department of Diabetes and Vascular Medicine, University of Exeter Medical School, Barrack Road, Exeter EX2 5AX, United Kingdom, the National Institute for Health Research Exeter Clinical Research Facility, Royal Devon and Exeter National Health Service Foundation Trust, Exeter EX2 5DW, United Kingdom, and
| | - Francesco Casanova
- the Department of Diabetes and Vascular Medicine, University of Exeter Medical School, Barrack Road, Exeter EX2 5AX, United Kingdom, the National Institute for Health Research Exeter Clinical Research Facility, Royal Devon and Exeter National Health Service Foundation Trust, Exeter EX2 5DW, United Kingdom, and
| | - Tim J Mitchell
- the Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Richard W Titball
- From the College of Life and Environmental Sciences, School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - C Peter Winlove
- the College of Engineering, Mathematics and Physical Sciences, School of Physics, University of Exeter, Exeter EX4 4QL, United Kingdom
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Al-Homsi L, Al-Okla S, Abbady AQ. Preparation of Specific Polyclonal Antibody Against the Recombinant Mutacin Produced by sfGFP Fusion Protein Technology. Open Microbiol J 2015; 9:70-80. [PMID: 26668664 PMCID: PMC4676047 DOI: 10.2174/1874285801509010070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 02/19/2015] [Accepted: 03/26/2015] [Indexed: 11/22/2022] Open
Abstract
Mutacin I, a bacteriocin produced by streptococcus mutans, displays an antimicrobial activity against many
gram positive and some gram negative bacteria. Because of its medical importance, production of this short peptide in
large scale for future applications is a significant challenge. This work described the improvement of a novel system to
produce the recombinant mutacin using fusion protein technology. The short peptide was expressed directly as a fusion protein with a superfolder form of the green florescent protein
(sfGFP), resulting in a high yield expression of soluble sfGFP-mutacin fusion protein (30 kDa) in the cytoplasm of
E. coli. Mutacin was released from the fusion by enzymatic cleavage at the tobacco etch virus (TEV) protease recognition
site and separated from the carrier sfGFP by nickel affinity and gel filtration chromatography. An additional advantage of
this fusion system was tested in the generation of mutacin-specific polyclonal antibodies. Specific anti-mutacin IgGs
were affinity purified, and were able to recognize the mutacin-sfGFP fusion protein or the cleaved forms of mutacin. Even though it was efficiently produced (25 mg/L) by this method, pure mutacin was devoid of antibiotic activity. Fourier
transform infrared spectroscopy (FTIR) analysis revealed the absence of thioether bonds in the purified mutacin, which
are critical for final structure and function of this antibiotic. Determining whether the activity of pure mutacin could be
recovered by the reformation of such structures by chemical reaction needs more investigations. The development of this
system will provide large quantities of mutacin for future studies and applications as broad spectrum antibacterial peptide.
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Affiliation(s)
- Lamis Al-Homsi
- Department of Biotechnology, Faculty of Agriculture, Damascus University, Syria
| | - Souad Al-Okla
- Department of Animal Biology, Faculty of Sciences, Damascus University, Syria
| | - Abdul Q Abbady
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), Damascus, Syria
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Gil C, Dorca-Arévalo J, Blasi J. Clostridium Perfringens Epsilon Toxin Binds to Membrane Lipids and Its Cytotoxic Action Depends on Sulfatide. PLoS One 2015; 10:e0140321. [PMID: 26452234 PMCID: PMC4599917 DOI: 10.1371/journal.pone.0140321] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 09/24/2015] [Indexed: 12/23/2022] Open
Abstract
Epsilon toxin (Etx) is one of the major lethal toxins produced by Clostridium perfringens types B and D, being the causal agent of fatal enterotoxemia in animals, mainly sheep and goats. Etx is synthesized as a non-active prototoxin form (proEtx) that becomes active upon proteolytic activation. Etx exhibits a cytotoxic effect through the formation of a pore in the plasma membrane of selected cell targets where Etx specifically binds due to the presence of specific receptors. However, the identity and nature of host receptors of Etx remain a matter of controversy. In the present study, the interactions between Etx and membrane lipids from the synaptosome-enriched fraction from rat brain (P2 fraction) and MDCK cell plasma membrane preparations were analyzed. Our findings show that both Etx and proEtx bind to lipids extracted from lipid rafts from the two different models as assessed by protein-lipid overlay assay. Lipid rafts are membrane microdomains enriched in cholesterol and sphingolipids. Binding of proEtx to sulfatide, phosphatidylserine, phosphatidylinositol (3)-phosphate and phosphatidylinositol (5)-phosphate was detected. Removal of the sulphate groups via sulfatase treatment led to a dramatic decrease in Etx-induced cytotoxicity, but not in proEtx-GFP binding to MDCK cells or a significant shift in oligomer formation, pointing to a role of sulfatide in pore formation in rafts but not in toxin binding to the target cell membrane. These results show for the first time the interaction between Etx and membrane lipids from host tissue and point to a major role for sulfatides in C. perfringens epsilon toxin pathophysiology.
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Affiliation(s)
- Carles Gil
- Departament de Bioquímica i Biologia Molecular and Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Catalunya, Spain
- * E-mail: (JB); (CG)
| | - Jonatan Dorca-Arévalo
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, School of Medicine, Universitat de Barcelona, L’Hospitalet de Llobregat, Barcelona, Spain
- IDIBELL-Bellvitge Biomedical Research Institute, L’Hospitalet de Llobregat, Barcelona, Spain
| | - Juan Blasi
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, School of Medicine, Universitat de Barcelona, L’Hospitalet de Llobregat, Barcelona, Spain
- IDIBELL-Bellvitge Biomedical Research Institute, L’Hospitalet de Llobregat, Barcelona, Spain
- * E-mail: (JB); (CG)
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Rumah KR, Ma Y, Linden JR, Oo ML, Anrather J, Schaeren-Wiemers N, Alonso MA, Fischetti VA, McClain MS, Vartanian T. The Myelin and Lymphocyte Protein MAL Is Required for Binding and Activity of Clostridium perfringens ε-Toxin. PLoS Pathog 2015; 11:e1004896. [PMID: 25993478 PMCID: PMC4439126 DOI: 10.1371/journal.ppat.1004896] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 04/19/2015] [Indexed: 12/18/2022] Open
Abstract
Clostridium perfringens ε-toxin (ETX) is a potent pore-forming toxin responsible for a central nervous system (CNS) disease in ruminant animals with characteristics of blood-brain barrier (BBB) dysfunction and white matter injury. ETX has been proposed as a potential causative agent for Multiple Sclerosis (MS), a human disease that begins with BBB breakdown and injury to myelin forming cells of the CNS. The receptor for ETX is unknown. Here we show that both binding of ETX to mammalian cells and cytotoxicity requires the tetraspan proteolipid Myelin and Lymphocyte protein (MAL). While native Chinese Hamster Ovary (CHO) cells are resistant to ETX, exogenous expression of MAL in CHO cells confers both ETX binding and susceptibility to ETX-mediated cell death. Cells expressing rat MAL are ~100 times more sensitive to ETX than cells expressing similar levels of human MAL. Insertion of the FLAG sequence into the second extracellular loop of MAL abolishes ETX binding and cytotoxicity. ETX is known to bind specifically and with high affinity to intestinal epithelium, renal tubules, brain endothelial cells and myelin. We identify specific binding of ETX to these structures and additionally show binding to retinal microvasculature and the squamous epithelial cells of the sclera in wild-type mice. In contrast, there is a complete absence of ETX binding to tissues from MAL knockout (MAL-/-) mice. Furthermore, MAL-/- mice exhibit complete resistance to ETX at doses in excess of 1000 times the symptomatic dose for wild-type mice. We conclude that MAL is required for both ETX binding and cytotoxicity.
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Affiliation(s)
- Kareem Rashid Rumah
- Brain and Mind Research Institute, Weill Cornell Medical College, New York City, New York, United States of America
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York City, New York, United States of America
| | - Yinghua Ma
- Brain and Mind Research Institute, Weill Cornell Medical College, New York City, New York, United States of America
| | - Jennifer R. Linden
- Brain and Mind Research Institute, Weill Cornell Medical College, New York City, New York, United States of America
| | - Myat Lin Oo
- Brain and Mind Research Institute, Weill Cornell Medical College, New York City, New York, United States of America
| | - Josef Anrather
- Brain and Mind Research Institute, Weill Cornell Medical College, New York City, New York, United States of America
| | - Nicole Schaeren-Wiemers
- Neurobiology, Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Miguel A. Alonso
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, Madrid, Spain
| | - Vincent A. Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York City, New York, United States of America
| | - Mark S. McClain
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Timothy Vartanian
- Brain and Mind Research Institute, Weill Cornell Medical College, New York City, New York, United States of America
- * E-mail:
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Identification of tyrosine 71 as a critical residue for the cytotoxic activity of Clostridium perfringens epsilon toxin towards MDCK cells. J Microbiol 2015; 53:141-6. [PMID: 25626370 DOI: 10.1007/s12275-015-4523-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/24/2014] [Accepted: 12/11/2014] [Indexed: 01/18/2023]
Abstract
Clostridium perfringens epsilon toxin (Etx) is an extremely potent toxin, causing fatal enterotoxaemia in many animals. Several amino acids in domains I and II have been proposed to be critical for Etx to interact with MDCK cells. However, the critical amino acids in domain III remain undefined. Therefore, we assessed the effects of aromatic amino acids in domain III on Etx activity in this study. All of the results indicated that Y71 was critical for the cytotoxic activity of Etx towards MDCK cells, and this activity was dependent on the existence of an aromatic ring residue in position 71. Additionally, mutations in Y71 did not affect the binding of Etx to MDCK cells, indicating that Y71 is not a receptor binding site for Etx. In summary, we identified an amino acid in domain III that is important for the cytotoxic activity of Etx, thereby providing information on the structure-function relationship of Etx.
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Vrecl M, Babnik M, Diacci U, Benoit E, Frangež R. Effect of the ostreolysin A/pleurotolysin B pore-forming complex on neuroblastoma cell morphology and intracellular Ca²⁺ activity. Toxicol Sci 2015; 144:276-83. [PMID: 25556216 DOI: 10.1093/toxsci/kfu316] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ostreolysin A (OlyA) and pleurotolysin B (PlyB), isolated from edible oyster mushrooms, form a cytolytic complex (OlyA/PlyB) in membrane cells that causes respiratory arrest. This study evaluated the mechanisms underlying cytotoxic OlyA/PlyB activity in neuroblastoma NG108-15 cells. Confocal microscopy with morphometric analysis revealed that OlyA/PlyB increased the 3-dimensional projected area of differentiated cells. Iso-osmotic replacement of NaCl by sucrose or Na-isethionate prevented the cellular swelling. This suggests that formation of cellular edema requires the presence of Na(+) and/or Cl(-) in the extracellular space and may be related to an influx of Na(+) and/or a shift in Cl(-), which induce a marked influx of water that is ultimately responsible for cellular swelling. In addition, extracellular Ca(2+) moderately contributed to the swelling because benzamil (10 µM), a 3Na(+)/Ca(2+) exchange (NCX) inhibitor, and Ca(2+)-free medium partially prevented this response. Fluorometric measurements revealed that OlyA/PlyB, at approximately 15-fold higher concentrations, increased the intracellular Ca(2+) activity [Ca(2+)]i. This increase was dependent on the presence of Na(+) and Ca(2+) in the external medium and was sensitive to benzamil. It is thus likely that a switch in the NCX mode, associated with the de novo formation of non-selective ion pores by OlyA/PlyB in cellular plasma membranes, plays an important role in this effect. Overall, OlyA/PlyB affects neuroblastoma cell morphology and Ca(2+) homeostasis to influence the toxin-induced respiratory arrest.
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Affiliation(s)
- Milka Vrecl
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
| | - Monika Babnik
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
| | - Uroš Diacci
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
| | - Evelyne Benoit
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
| | - Robert Frangež
- *Veterinary Faculty, Institute of Anatomy, Histology and Embryology, Veterinary Faculty, Institute of Physiology, Pharmacology and Toxicology, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia and CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie et Développement Bât. 32-33, 91198 Gif sur Yvette cedex, France
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Dorca-Arévalo J, Pauillac S, Díaz-Hidalgo L, Martín-Satué M, Popoff MR, Blasi J. Correlation between in vitro cytotoxicity and in vivo lethal activity in mice of epsilon toxin mutants from Clostridium perfringens. PLoS One 2014; 9:e102417. [PMID: 25013927 PMCID: PMC4094505 DOI: 10.1371/journal.pone.0102417] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/19/2014] [Indexed: 12/21/2022] Open
Abstract
Epsilon toxin (Etx) from Clostridium perfringens is a pore-forming protein with a lethal effect on livestock, producing severe enterotoxemia characterized by general edema and neurological alterations. Site-specific mutations of the toxin are valuable tools to study the cellular and molecular mechanism of the toxin activity. In particular, mutants with paired cysteine substitutions that affect the membrane insertion domain behaved as dominant-negative inhibitors of toxin activity in MDCK cells. We produced similar mutants, together with a well-known non-toxic mutant (Etx-H106P), as green fluorescent protein (GFP) fusion proteins to perform in vivo studies in an acutely intoxicated mouse model. The mutant (GFP-Etx-I51C/A114C) had a lethal effect with generalized edema, and accumulated in the brain parenchyma due to its ability to cross the blood-brain barrier (BBB). In the renal system, this mutant had a cytotoxic effect on distal tubule epithelial cells. The other mutants studied (GFP-Etx-V56C/F118C and GFP-Etx-H106P) did not have a lethal effect or cross the BBB, and failed to induce a cytotoxic effect on renal epithelial cells. These data suggest a direct correlation between the lethal effect of the toxin, with its cytotoxic effect on the kidney distal tubule cells, and the ability to cross the BBB.
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Affiliation(s)
- Jonatan Dorca-Arévalo
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
- IDIBELL-Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Serge Pauillac
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, Paris, France
| | - Laura Díaz-Hidalgo
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Mireia Martín-Satué
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
- IDIBELL-Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Michel R. Popoff
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, Paris, France
| | - Juan Blasi
- Laboratory of Cellular and Molecular Neuroscience, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
- IDIBELL-Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona, Spain
- * E-mail:
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Türkcan S, Richly MU, Bouzigues CI, Allain JM, Alexandrou A. Receptor displacement in the cell membrane by hydrodynamic force amplification through nanoparticles. Biophys J 2014; 105:116-26. [PMID: 23823230 DOI: 10.1016/j.bpj.2013.05.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 05/07/2013] [Accepted: 05/20/2013] [Indexed: 12/11/2022] Open
Abstract
We introduce an intrinsically multiplexed and easy to implement method to apply an external force to a biomolecule and thus probe its interaction with a second biomolecule or, more generally, its environment (for example, the cell membrane). We take advantage of the hydrodynamic interaction with a controlled fluid flow within a microfluidic channel to apply a force. By labeling the biomolecule with a nanoparticle that acts as a kite and increases the hydrodynamic interaction with the fluid, the drag induced by convection becomes important. We use this approach to track the motion of single membrane receptors, the Clostridium perfringens ε-toxin (CPεT) receptors that are confined in lipid raft platforms, and probe their interaction with the environment. Under external force, we observe displacements over distances up to 10 times the confining domain diameter due to elastic deformation of a barrier and return to the initial position after the flow is stopped. Receptors can also jump over such barriers. Analysis of the receptor motion characteristics before, during, and after a force is applied via the flow indicates that the receptors are displaced together with their confining raft platform. Experiments before and after incubation with latrunculin B reveal that the barriers are part of the actin cytoskeleton and have an average spring constant of 2.5 ± 0.6 pN/μm before vs. 0.6 ± 0.2 pN/μm after partial actin depolymerization. Our data, in combination with our previous work demonstrating that the ε-toxin receptor confinement is not influenced by the cytoskeleton, imply that it is the raft platform and its constituents rather than the receptor itself that encounters and deforms the barriers formed by the actin cytoskeleton.
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Affiliation(s)
- Silvan Türkcan
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale U696, Palaiseau Cedex, France
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Clostridium perfringens epsilon toxin: a malevolent molecule for animals and man? Toxins (Basel) 2013; 5:2138-60. [PMID: 24284826 PMCID: PMC3847718 DOI: 10.3390/toxins5112138] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/30/2013] [Accepted: 10/31/2013] [Indexed: 12/27/2022] Open
Abstract
Clostridium perfringens is a prolific, toxin-producing anaerobe causing multiple diseases in humans and animals. One of these toxins is epsilon, a 33 kDa protein produced by Clostridium perfringens (types B and D) that induces fatal enteric disease of goats, sheep and cattle. Epsilon toxin (Etx) belongs to the aerolysin-like toxin family. It contains three distinct domains, is proteolytically-activated and forms oligomeric pores on cell surfaces via a lipid raft-associated protein(s). Vaccination controls Etx-induced disease in the field. However, therapeutic measures are currently lacking. This review initially introduces C. perfringens toxins, subsequently focusing upon the Etx and its biochemistry, disease characteristics in various animals that include laboratory models (in vitro and in vivo), and finally control mechanisms (vaccines and therapeutics).
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Los FCO, Randis TM, Aroian RV, Ratner AJ. Role of pore-forming toxins in bacterial infectious diseases. Microbiol Mol Biol Rev 2013; 77:173-207. [PMID: 23699254 PMCID: PMC3668673 DOI: 10.1128/mmbr.00052-12] [Citation(s) in RCA: 293] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pore-forming toxins (PFTs) are the most common bacterial cytotoxic proteins and are required for virulence in a large number of important pathogens, including Streptococcus pneumoniae, group A and B streptococci, Staphylococcus aureus, Escherichia coli, and Mycobacterium tuberculosis. PFTs generally disrupt host cell membranes, but they can have additional effects independent of pore formation. Substantial effort has been devoted to understanding the molecular mechanisms underlying the functions of certain model PFTs. Likewise, specific host pathways mediating survival and immune responses in the face of toxin-mediated cellular damage have been delineated. However, less is known about the overall functions of PFTs during infection in vivo. This review focuses on common themes in the area of PFT biology, with an emphasis on studies addressing the roles of PFTs in in vivo and ex vivo models of colonization or infection. Common functions of PFTs include disruption of epithelial barrier function and evasion of host immune responses, which contribute to bacterial growth and spreading. The widespread nature of PFTs make this group of toxins an attractive target for the development of new virulence-targeted therapies that may have broad activity against human pathogens.
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Affiliation(s)
| | - Tara M. Randis
- Department of Pediatrics, Columbia University, New York, New York, USA
| | - Raffi V. Aroian
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California, USA
| | - Adam J. Ratner
- Department of Pediatrics, Columbia University, New York, New York, USA
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Affiliation(s)
| | - Sergey M. Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, U.S.A
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Oligomerization of Clostridium perfringens epsilon toxin is dependent upon caveolins 1 and 2. PLoS One 2012; 7:e46866. [PMID: 23056496 PMCID: PMC3462777 DOI: 10.1371/journal.pone.0046866] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/06/2012] [Indexed: 01/27/2023] Open
Abstract
Evidence from multiple studies suggests that Clostridium perfringens ε-toxin is a pore-forming toxin, assembling into oligomeric complexes in the plasma membrane of sensitive cells. In a previous study, we used gene-trap mutagenesis to identify mammalian factors contributing to toxin activity, including caveolin-2 (CAV2). In this study, we demonstrate the importance of caveolin-2 and its interaction partner, caveolin-1 (CAV1), in ε-toxin-induced cytotoxicity. Using CAV2-specific shRNA in a toxin-sensitive human kidney cell line, ACHN, we confirmed that cells deficient in CAV2 exhibit increased resistance to ε-toxin. Similarly, using CAV1-specific shRNA, we demonstrate that cells deficient in CAV1 also exhibit increased resistance to the toxin. Immunoprecipitation of CAV1 and CAV2 from ε-toxin-treated ACHN cells demonstrated interaction of both CAV1 and -2 with the toxin. Furthermore, blue-native PAGE indicated that the toxin and caveolins were components of a 670 kDa protein complex. Although ε-toxin binding was only slightly perturbed in caveolin-deficient cells, oligomerization of the toxin was dramatically reduced in both CAV1- and CAV2-deficient cells. These results indicate that CAV1 and -2 potentiate ε-toxin induced cytotoxicity by promoting toxin oligomerization – an event which is requisite for pore formation and, by extension, cell death.
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Ivie SE, McClain MS. Identification of amino acids important for binding of Clostridium perfringens epsilon toxin to host cells and to HAVCR1. Biochemistry 2012; 51:7588-95. [PMID: 22938730 PMCID: PMC3534817 DOI: 10.1021/bi300690a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Clostridium perfringens epsilon toxin belongs to the aerolysin-like family of pore-forming toxins and is one of the most potent bacterial toxins known. The epsilon toxin causes fatal enterotoxemia in sheep, goats, and possibly humans. Evidence indicates that the toxin binds to protein receptors including hepatitis A virus cellular receptor 1 (HAVCR1), but the region of the toxin responsible for cell binding has not been identified. In the present study, we identify amino acids within the epsilon toxin important for this cell interaction. Site-specific mutagenesis was used to investigate the role of a surface-accessible cluster of aromatic amino acids, and purified mutant proteins were tested in a series of cell-culture assays to assess cytotoxic activity and cell binding. When added to cells, four mutant proteins (Etx-Y29E, Etx-Y30E, Etx-Y36E and Etx-Y196E) were severely impaired in their ability to not only kill host cells, but also in their ability to permeabilize the plasma membrane. Circular dichroism spectroscopy and thermal stability studies revealed that the wild-type and mutant proteins were similarly folded. Additional experiments revealed that these mutant proteins were defective in binding to host cells and to HAVCR1. These data indicate that an amino acid motif including Y29, Y30, Y36, and Y196 is important for the ability of epsilon toxin to interact with cells and HAVCR1.
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Affiliation(s)
- Susan E. Ivie
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Mark S. McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
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Türkcan S, Masson JB, Casanova D, Mialon G, Gacoin T, Boilot JP, Popoff MR, Alexandrou A. Observing the confinement potential of bacterial pore-forming toxin receptors inside rafts with nonblinking Eu(3+)-doped oxide nanoparticles. Biophys J 2012; 102:2299-308. [PMID: 22677383 DOI: 10.1016/j.bpj.2012.03.072] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 03/20/2012] [Accepted: 03/23/2012] [Indexed: 12/26/2022] Open
Abstract
We track single toxin receptors on the apical cell membrane of MDCK cells with Eu-doped oxide nanoparticles coupled to two toxins of the pore-forming toxin family: α-toxin of Clostridium septicum and ε-toxin of Clostridium perfringens. These nonblinking and photostable labels do not perturb the motion of the toxin receptors and yield long uninterrupted trajectories with mean localization precision of 30 nm for acquisition times of 51.3 ms. We were thus able to study the toxin-cell interaction at the single-molecule level. Toxins bind to receptors that are confined within zones of mean area 0.40 ± 0.05 μm(2). Assuming that the receptors move according to the Langevin equation of motion and using Bayesian inference, we determined mean diffusion coefficients of 0.16 ± 0.01 μm(2)/s for both toxin receptors. Moreover, application of this approach revealed a force field within the domain generated by a springlike confining potential. Both toxin receptors were found to experience forces characterized by a mean spring constant of 0.30 ± 0.03 pN/μm at 37°C. Furthermore, both toxin receptors showed similar distributions of diffusion coefficient, domain area, and spring constant. Control experiments before and after incubation with cholesterol oxidase and sphingomyelinase show that these two enzymes disrupt the confinement domains and lead to quasi-free motion of the toxin receptors. Our control data showing cholesterol and sphingomyelin dependence as well as independence of actin depolymerization and microtubule disruption lead us to attribute the confinement of both receptors to lipid rafts. These toxins require oligomerization to develop their toxic activity. The confined nature of the toxin receptors leads to a local enhancement of the toxin monomer concentration and may thus explain the virulence of this toxin family.
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Affiliation(s)
- Silvan Türkcan
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale U696, Palaiseau, France.
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Dorca-Arévalo J, Martín-Satué M, Blasi J. Characterization of the high affinity binding of epsilon toxin from Clostridium perfringens to the renal system. Vet Microbiol 2012; 157:179-89. [PMID: 22264388 DOI: 10.1016/j.vetmic.2011.12.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 12/13/2011] [Accepted: 12/15/2011] [Indexed: 10/14/2022]
Abstract
Epsilon toxin (ε-toxin), produced by Clostridium perfringens types B and D, causes fatal enterotoxaemia in livestock. In the renal system, the toxin binds to target cells before oligomerization, pore formation and cell death. Still, there is little information about the cellular and molecular mechanism involved in the initial steps of the cytotoxic action of ε-toxin, including the specific binding to the target sensitive cells. In the present report, the binding step of ε-toxin to the MDCK cell line is characterized by means of an ELISA-based binding assay with recombinant ε-toxin-green fluorescence protein (ε-toxin-GFP) and ε-prototoxin-GFP. In addition, different treatments with Pronase E, detergents, N-glycosidase F and beta-elimination on MDCK cells and renal cryosections have been performed to further characterize the ε-toxin binding. The ELISA assays revealed a single binding site with a similar dissociation constant (K(d)) for ε-toxin-GFP and ε-prototoxin-GFP, but a three-fold increase in B(max) levels in the case of ε-toxin-GFP. Double staining on kidney cryoslices with lectins and ε-prototoxin-GFP revealed specific binding to distal and collecting tubule cells. In addition, experiments on kidney and bladder cryoslices demonstrated the specific binding to distal tubule of a range of mammalian renal systems. Pronase E and beta-elimination treatments on kidney cryoslices and MDCK cells revealed that the binding of ε-toxin in renal system is mediated by a O-glycoprotein. Detergent treatments revealed that the integrity of the plasma membrane is required for the binding of ε-toxin to its receptor.
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Affiliation(s)
- Jonatan Dorca-Arévalo
- Department of Pathology and Experimental Therapeutics, School of Medicine, Campus of Bellvitge, Health Universitat de Barcelona Campus (HUBc), University of Barcelona, c/Feixa Llarga s/n 08907, L'Hospitalet de Llobregat, Spain
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Robertson SL, Li J, Uzal FA, McClane BA. Evidence for a prepore stage in the action of Clostridium perfringens epsilon toxin. PLoS One 2011; 6:e22053. [PMID: 21814565 PMCID: PMC3140917 DOI: 10.1371/journal.pone.0022053] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Accepted: 06/16/2011] [Indexed: 11/25/2022] Open
Abstract
Clostridium perfringens epsilon toxin (ETX) rapidly kills MDCK II cells at 37°C, but not 4°C. The current study shows that, in MDCK II cells, ETX binds and forms an oligomeric complex equally well at 37°C and 4°C but only forms a pore at 37°C. However, the complex formed in MDCK cells treated with ETX at 4°C has the potential to form an active pore, since shifting those cells to 37°C results in rapid cytotoxicity. Those results suggested that the block in pore formation at 4°C involves temperature-related trapping of ETX in a prepore intermediate on the MDCK II cell plasma membrane surface. Evidence supporting this hypothesis was obtained when the ETX complex in MDCK II cells was shown to be more susceptible to pronase degradation when formed at 4°C vs. 37°C; this result is consistent with ETX complex formed at 4°C remaining present in an exposed prepore on the membrane surface, while the ETX prepore complex formed at 37°C is unaccessible to pronase because it has inserted into the plasma membrane to form an active pore. In addition, the ETX complex rapidly dissociated from MDCK II cells at 4°C, but not 37°C; this result is consistent with the ETX complex being resistant to dissociation at 37°C because it has inserted into membranes, while the ETX prepore readily dissociates from cells at 4°C because it remains on the membrane surface. These results support the identification of a prepore stage in ETX action and suggest a revised model for ETX cytotoxicity, i) ETX binds to an unidentified receptor, ii) ETX oligomerizes into a prepore on the membrane surface, and iii) the prepore inserts into membranes, in a temperature-sensitive manner, to form an active pore.
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Affiliation(s)
- Susan L. Robertson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jihong Li
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Francisco A. Uzal
- California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Bruce A. McClane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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Bokori-Brown M, Savva CG, Fernandes da Costa SP, Naylor CE, Basak AK, Titball RW. Molecular basis of toxicity of Clostridium perfringens epsilon toxin. FEBS J 2011; 278:4589-601. [PMID: 21518257 DOI: 10.1111/j.1742-4658.2011.08140.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Clostridium perfringens ε-toxin is produced by toxinotypes B and D strains. The toxin is the aetiological agent of dysentery in newborn lambs but is also associated with enteritis and enterotoxaemia in goats, calves and foals. It is considered to be a potential biowarfare or bioterrorism agent by the US Government Centers for Disease Control and Prevention. The relatively inactive 32.9 kDa prototoxin is converted to active mature toxin by proteolytic cleavage, either by digestive proteases of the host, such as trypsin and chymotrypsin, or by C. perfringens λ-protease. In vivo, the toxin appears to target the brain and kidneys, but relatively few cell lines are susceptible to the toxin, and most work has been carried out using Madin-Darby canine kidney (MDCK) cells. The binding of ε-toxin to MDCK cells and rat synaptosomal membranes is associated with the formation of a stable, high molecular weight complex. The crystal structure of ε-toxin reveals similarity to aerolysin from Aeromonas hydrophila, parasporin-2 from Bacillus thuringiensis and a lectin from Laetiporus sulphureus. Like these toxins, ε-toxin appears to form heptameric pores in target cell membranes. The exquisite specificity of the toxin for specific cell types suggests that it binds to a receptor found only on these cells.
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Affiliation(s)
- Monika Bokori-Brown
- Biosciences, College of Life and Environmental Sciences, University of Exeter, UK
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Ivie SE, Fennessey CM, Sheng J, Rubin DH, McClain MS. Gene-trap mutagenesis identifies mammalian genes contributing to intoxication by Clostridium perfringens ε-toxin. PLoS One 2011; 6:e17787. [PMID: 21412435 PMCID: PMC3055893 DOI: 10.1371/journal.pone.0017787] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 02/14/2011] [Indexed: 12/13/2022] Open
Abstract
The Clostridium perfringens ε-toxin is an extremely potent toxin associated with lethal toxemias in domesticated ruminants and may be toxic to humans. Intoxication results in fluid accumulation in various tissues, most notably in the brain and kidneys. Previous studies suggest that the toxin is a pore-forming toxin, leading to dysregulated ion homeostasis and ultimately cell death. However, mammalian host factors that likely contribute to ε-toxin-induced cytotoxicity are poorly understood. A library of insertional mutant Madin Darby canine kidney (MDCK) cells, which are highly susceptible to the lethal affects of ε-toxin, was used to select clones of cells resistant to ε-toxin-induced cytotoxicity. The genes mutated in 9 surviving resistant cell clones were identified. We focused additional experiments on one of the identified genes as a means of validating the experimental approach. Gene expression microarray analysis revealed that one of the identified genes, hepatitis A virus cellular receptor 1 (HAVCR1, KIM-1, TIM1), is more abundantly expressed in human kidney cell lines than it is expressed in human cells known to be resistant to ε-toxin. One human kidney cell line, ACHN, was found to be sensitive to the toxin and expresses a larger isoform of the HAVCR1 protein than the HAVCR1 protein expressed by other, toxin-resistant human kidney cell lines. RNA interference studies in MDCK and in ACHN cells confirmed that HAVCR1 contributes to ε-toxin-induced cytotoxicity. Additionally, ε-toxin was shown to bind to HAVCR1 in vitro. The results of this study indicate that HAVCR1 and the other genes identified through the use of gene-trap mutagenesis and RNA interference strategies represent important targets for investigation of the process by which ε-toxin induces cell death and new targets for potential therapeutic intervention.
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Affiliation(s)
- Susan E. Ivie
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Christine M. Fennessey
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Jinsong Sheng
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Donald H. Rubin
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Research Medicine, VA Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Mark S. McClain
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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Lonchamp E, Dupont JL, Wioland L, Courjaret R, Mbebi-Liegeois C, Jover E, Doussau F, Popoff MR, Bossu JL, de Barry J, Poulain B. Clostridium perfringens epsilon toxin targets granule cells in the mouse cerebellum and stimulates glutamate release. PLoS One 2010; 5:e13046. [PMID: 20941361 PMCID: PMC2948003 DOI: 10.1371/journal.pone.0013046] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 09/03/2010] [Indexed: 11/19/2022] Open
Abstract
Epsilon toxin (ET) produced by C. perfringens types B and D is a highly potent pore-forming toxin. ET-intoxicated animals express severe neurological disorders that are thought to result from the formation of vasogenic brain edemas and indirect neuronal excitotoxicity. The cerebellum is a predilection site for ET damage. ET has been proposed to bind to glial cells such as astrocytes and oligodendrocytes. However, the possibility that ET binds and attacks the neurons remains an open question. Using specific anti-ET mouse polyclonal antibodies and mouse brain slices preincubated with ET, we found that several brain structures were labeled, the cerebellum being a prominent one. In cerebellar slices, we analyzed the co-staining of ET with specific cell markers, and found that ET binds to the cell body of granule cells, oligodendrocytes, but not astrocytes or nerve endings. Identification of granule cells as neuronal ET targets was confirmed by the observation that ET induced intracellular Ca(2+) rises and glutamate release in primary cultures of granule cells. In cultured cerebellar slices, whole cell patch-clamp recordings of synaptic currents in Purkinje cells revealed that ET greatly stimulates both spontaneous excitatory and inhibitory activities. However, pharmacological dissection of these effects indicated that they were only a result of an increased granule cell firing activity and did not involve a direct action of the toxin on glutamatergic nerve terminals or inhibitory interneurons. Patch-clamp recordings of granule cell somata showed that ET causes a decrease in neuronal membrane resistance associated with pore-opening and depolarization of the neuronal membrane, which subsequently lead to the firing of the neuronal network and stimulation of glutamate release. This work demonstrates that a subset of neurons can be directly targeted by ET, suggesting that part of ET-induced neuronal damage observed in neuronal tissue is due to a direct effect of ET on neurons.
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Affiliation(s)
- Etienne Lonchamp
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Jean-Luc Dupont
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Laetitia Wioland
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Raphaël Courjaret
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Corinne Mbebi-Liegeois
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Emmanuel Jover
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Frédéric Doussau
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Michel R. Popoff
- Unité des Anaérobies et Leurs Toxines, Institut Pasteur à Paris, Paris, France
| | - Jean-Louis Bossu
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Jean de Barry
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
| | - Bernard Poulain
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives UPR3212, Strasbourg, France
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Lewis M, Weaver CD, McClain MS. Identification of Small Molecule Inhibitors of Clostridium perfringens ε-Toxin Cytotoxicity Using a Cell-Based High-Throughput Screen. Toxins (Basel) 2010; 2:1825-1847. [PMID: 20721308 PMCID: PMC2922765 DOI: 10.3390/toxins2071825] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The Clostridium perfringens epsilon toxin, a select agent, is responsible for a severe, often fatal enterotoxemia characterized by edema in the heart, lungs, kidney, and brain. The toxin is believed to be an oligomeric pore-forming toxin. Currently, there is no effective therapy for countering the cytotoxic activity of the toxin in exposed individuals. Using a robust cell-based high-throughput screening (HTS) assay, we screened a 151,616-compound library for the ability to inhibit ε-toxin-induced cytotoxicity. Survival of MDCK cells exposed to the toxin was assessed by addition of resazurin to detect metabolic activity in surviving cells. The hit rate for this screen was 0.6%. Following a secondary screen of each hit in triplicate and assays to eliminate false positives, we focused on three structurally-distinct compounds: an N-cycloalkylbenzamide, a furo[2,3-b]quinoline, and a 6H-anthra[1,9-cd]isoxazol. None of the three compounds appeared to inhibit toxin binding to cells or the ability of the toxin to form oligomeric complexes. Additional assays demonstrated that two of the inhibitory compounds inhibited ε-toxin-induced permeabilization of MDCK cells to propidium iodide. Furthermore, the two compounds exhibited inhibitory effects on cells pre-treated with toxin. Structural analogs of one of the inhibitors identified through the high-throughput screen were analyzed and provided initial structure-activity data. These compounds should serve as the basis for further structure-activity refinement that may lead to the development of effective anti-ε-toxin therapeutics.
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Affiliation(s)
- Michelle Lewis
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA;
| | - Charles David Weaver
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA;
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37235, USA;
| | - Mark S. McClain
- Department of Medicine, Vanderbilt University, Nashville, TN 37235, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-615-322-2035; Fax: +1-615-343-6160
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Lebrun M, Mainil JG, Linden A. Cattle enterotoxaemia and Clostridium perfringens
: description, diagnosis and prophylaxis. Vet Rec 2010; 167:13-22. [DOI: 10.1136/vr.167.1.12] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- M. Lebrun
- Association de Santé et d'Identification Animale; Allée des Artisans 2 5590 Ciney Belgium
| | - J. G. Mainil
- Bacteriology Section; Department of Infectious Diseases; Faculty of Veterinary Medicine; University of Liège; B43A Boulevard de Colonster 20 4000 Liège Belgium
| | - A. Linden
- Bacteriology Section; Department of Infectious Diseases; Faculty of Veterinary Medicine; University of Liège; B43A Boulevard de Colonster 20 4000 Liège Belgium
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Fernandez Miyakawa ME, Zabal O, Silberstein C. Clostridium perfringens epsilon toxin is cytotoxic for human renal tubular epithelial cells. Hum Exp Toxicol 2010; 30:275-82. [PMID: 20488848 DOI: 10.1177/0960327110371700] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Clostridium perfringens epsilon toxin (ETX) is responsible for a fatal enterotoxemia in different animal species, producing extensive renal damage, neurological disturbance and edema of lungs, heart and kidneys. However, there is no information about the susceptibility of humans to ETX. Here, we report that primary cultures of human renal tubular epithelial cells (HRTEC) exposed to ETX showed a marked swelling with subsequent large blebs surrounding most cells. The incubation of HRTEC with ETX produced a reduction of cell viability in a dose- and time-dependent manner. The CD(50) after 1-hour and 24-hour incubation were 3 µg/mL and 0.5 µg/mL, respectively. The pulse with ETX for 3 min was enough to produce a significant cytotoxic effect on HRTEC after 1-hour incubation. ETX binds to HRTEC forming a large complex of about 160 kDa similar to what was found in the Madin-Darby canine kidney (MDCK) cell line. The HRTEC could be a useful cell model to improve the understanding of the mechanisms involved on the cell damage mediated by ETX.
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Affiliation(s)
- Mariano E Fernandez Miyakawa
- Instituto de Patobiología, Centro Nacional de Investigaciones Agropecuarias, Instituto Nacional de Tecnología Agropecuaria, Buenos Aires, Argentina
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Souza AM, Reis JKP, Assis RA, Horta CC, Siqueira FF, Facchin S, Alvarenga ER, Castro CS, Salvarani FM, Silva ROS, Pires PS, Contigli C, Lobato FCF, Kalapothakis E. Molecular cloning and expression of epsilon toxin from Clostridium perfringens type D and tests of animal immunization. GENETICS AND MOLECULAR RESEARCH 2010; 9:266-76. [PMID: 20198582 DOI: 10.4238/vol9-1gmr711] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Epsilon toxin produced by Clostridium perfringens types B and D causes enterotoxemia in sheep, goats and calves. Enterotoxemia can cause acute or superacute disease, with sudden death of the affected animal. It provokes huge economic losses when large numbers of livestock are affected. Therapeutic intervention is challenging, because the disease progresses very rapidly. However, it can be prevented by immunization with specific immunogenic vaccines. We cloned the etx gene, encoding epsilon toxin, into vector pET-11a; recombinant epsilon toxin (rec-epsilon) was expressed in inclusion bodies and was used for animal immunization. Serum protection was evaluated and cross-serum neutralization tests were used to characterize the recombinant toxin. To analyze the potency of the toxin (as an antigen), rabbits were immunized with 50, 100 or 200 microg recombinant toxin, using aluminum hydroxide gel as an adjuvant. Titers of 10, 30 and 40 IU/mL were obtained, respectively. These titers were higher than the minimum level required by the European Pharmacopoeia (5 IU/mL) and by the USA Code of Federal Regulation (2 IU/mL). This rec-epsilon is a good candidate for vaccine production against enterotoxemia caused by epsilon toxin of C. perfringens type D.
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Affiliation(s)
- A M Souza
- Laboratório de Marcadores Moleculares e Biotecnologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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Pelish TM, McClain MS. Dominant-negative inhibitors of the Clostridium perfringens epsilon-toxin. J Biol Chem 2009; 284:29446-53. [PMID: 19720828 PMCID: PMC2785577 DOI: 10.1074/jbc.m109.021782] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 08/24/2009] [Indexed: 01/27/2023] Open
Abstract
The Clostridium perfringens epsilon-toxin is responsible for a severe, often lethal intoxication. In this study, we characterized dominant-negative inhibitors of the epsilon-toxin. Site-specific mutations were introduced into the gene encoding epsilon-toxin, and recombinant proteins were expressed in Escherichia coli. Paired cysteine substitutions were introduced at locations predicted to form a disulfide bond. One cysteine in each mutant was introduced into the membrane insertion domain of the toxin; the second cysteine was introduced into the protein backbone. Mutant proteins with cysteine substitutions at amino acid positions I51/A114 and at V56/F118 lacked detectable cytotoxic activity in a MDCK cell assay. Cytotoxic activity could be reconstituted in both mutant proteins by incubation with dithiothreitol, indicating that the lack of cytotoxic activity was attributable to the formation of a disulfide bond. Fluorescent labeling of the cysteines also indicated that the introduced cysteines participated in a disulfide bond. When equimolar mixtures of wild-type epsilon-toxin and mutant proteins were added to MDCK cells, the I51C/A114C and V56C/F118C mutant proteins each inhibited the activity of wild-type epsilon-toxin. Further analysis of the inhibitory activity of the I51C/A114C and V56C/F118C mutant proteins indicated that these proteins inhibit the ability of the active toxin to form stable oligomeric complexes in the context of MDCK cells. These results provide further insight into the properties of dominant-negative inhibitors of oligomeric pore-forming toxins and provide the basis for developing new therapeutics for treating intoxication by epsilon-toxin.
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Affiliation(s)
- Teal M. Pelish
- From the Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Mark S. McClain
- From the Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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Knapp O, Maier E, Benz R, Geny B, Popoff MR. Identification of the channel-forming domain of Clostridium perfringens Epsilon-toxin (ETX). BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2584-93. [PMID: 19835840 DOI: 10.1016/j.bbamem.2009.09.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 09/17/2009] [Accepted: 09/29/2009] [Indexed: 10/20/2022]
Abstract
Epsilon-toxin (ETX) is a potent toxin produced by Clostridium perfringens strains B and D. The bacteria are important pathogens in domestic animals and cause edema mediated by ETX. This toxin acts most likely by heptamer formation and rapid permeabilization of target cell membranes for monovalent anions and cations followed by a later entry of calcium. In this study, we compared the primary structure of ETX with that of the channel-forming stretches of a variety of binding components of A-B-types of toxins such as Anthrax protective antigen (PA), C2II of C2-toxin and Ib of Iota-toxin and found a remarkable homology to amino acids 151-180 of ETX. Site-directed mutagenesis of amino acids within the putative channel-forming domain resulted in changes of cytotoxicity and effects on channel characteristics in lipid bilayer experiments including changes of selectivity and partial channel block by methanethiosulfonate (MTS) reagents and antibodies against His(6)-tags from the trans-side of the lipid bilayer membranes.
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Affiliation(s)
- Oliver Knapp
- Department of Biotechnology, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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Binding of epsilon-toxin from Clostridium perfringens in the nervous system. Vet Microbiol 2008; 131:14-25. [PMID: 18406080 DOI: 10.1016/j.vetmic.2008.02.015] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 02/18/2008] [Accepted: 02/20/2008] [Indexed: 11/20/2022]
Abstract
Epsilon-toxin (epsilon-toxin), produced by Clostridium perfringens type D, is the main agent responsible for enterotoxaemia in livestock. Neurological disorders are a characteristic of the onset of toxin poisoning. Epsilon-Toxin accumulates specifically in the central nervous system, where it produces a glutamatergic-mediated excitotoxic effect. However, no detailed study of putative binding structures in the nervous tissue has been carried out to date. Here we attempt to identify specific acceptor moieties and cell targets for epsilon-toxin, not only in the mouse nervous system but also in the brains of sheep and cattle. An epsilon-toxin-GFP fusion protein was produced and used to incubate brain sections, which were then analyzed by confocal microscopy. The results clearly show specific binding of epsilon-toxin to myelin structures. epsilon-Prototoxin-GFP and epsilon-toxin-GFP, the inactive and active forms of the toxin, respectively, showed identical results. By means of pronase E treatment, we found that the binding was mainly associated to a protein component of the myelin. Myelinated peripheral nerve fibres were also stained by epsilon-toxin. Moreover, the binding to myelin was not only restricted to rodents, but was also found in humans, sheep and cattle. Curiously, in the brains of both sheep and cattle, the toxin strongly stained the vascular endothelium, a result that may explain the differences in potency and effect between species. Although the binding of epsilon-toxin to myelin does not directly explain its neurotoxic effect, this feature opens up a new line of enquiry into its mechanism of toxicity and establishes the usefulness of this toxin for the study of the mammalian nervous system.
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Chassin C, Bens M, de Barry J, Courjaret R, Bossu JL, Cluzeaud F, Ben Mkaddem S, Gibert M, Poulain B, Popoff MR, Vandewalle A. Pore-forming epsilon toxin causes membrane permeabilization and rapid ATP depletion-mediated cell death in renal collecting duct cells. Am J Physiol Renal Physiol 2007; 293:F927-37. [PMID: 17567938 DOI: 10.1152/ajprenal.00199.2007] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Clostridium perfringens epsilon toxin (ET) is a potent pore-forming cytotoxin causing fatal enterotoxemia in livestock. ET accumulates in brain and kidney, particularly in the renal distal-collecting ducts. ET binds and oligomerizes in detergent-resistant membranes (DRMs) microdomains and causes cell death. However, the causal linkage between membrane permeabilization and cell death is not clear. Here, we show that ET binds and forms 220-kDa insoluble complexes in plasma membrane DRMs of renal mpkCCD(cl4) collecting duct cells. Phosphatidylinositol-specific phospholipase C did not impair binding or the formation of ET complexes, suggesting that the receptor for ET is not GPI anchored. ET induced a dose-dependent fall in the transepithelial resistance and potential in confluent cells grown on filters, transiently stimulated Na+ absorption, and induced an inward ionic current and a sustained rise in [Ca2+]i. ET also induced rapid depletion of cellular ATP, and stimulated the AMP-activated protein kinase, a metabolic-sensing Ser/Thr kinase. ET also induced mitochondrial membrane permeabilization and mitochondrial-nuclear translocation of apoptosis-inducing factor, a potent caspase-independent cell death effector. Finally, ET induced cell necrosis characterized by a marked reduction in nucleus size without DNA fragmentation. DRM disruption by methyl-beta-cyclodextrin impaired ET oligomerization, and significantly reduced the influx of Na+ and [Ca2+]i, but did not impair ATP depletion and cell death caused by the toxin. These findings indicate that ET causes rapid necrosis of renal collecting duct cells and establish that ATP depletion-mediated cell death is not strictly correlated with the plasma membrane permeabilization and ion diffusion caused by the toxin.
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Affiliation(s)
- C Chassin
- Institut National de la Santé et de la Recherche Médicale U773, Centre de Recherche Biomédicale Bichat-Beaujon CRB3, Paris, France
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