title: EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin.
abstract: The pathogenic bacteria Clostridium difficile, Clostridium perfringens and Clostridium botulinum produce the binary actin ADP-ribosylating toxins CDT, iota and C2, respectively. These toxins are composed of a transport component (B) and a separate enzyme component (A). When both components assemble on the surface of mammalian target cells, the B components mediate the entry of the A components via endosomes into the cytosol. Here, the A components ADP-ribosylate G-actin, resulting in depolymerization of F-actin, cell-rounding and eventually death. In the present study, we demonstrate that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA), a compound that protects cells from multiple toxins and viruses, also protects different mammalian epithelial cells from all three binary actin ADP-ribosylating toxins. In contrast, EGA did not inhibit the intoxication of cells with Clostridium difficile toxins A and B, indicating a possible different entry route for this toxin. EGA does not affect either the binding of the C2 toxin to the cells surface or the enzyme activity of the A components of CDT, iota and C2, suggesting that this compound interferes with cellular uptake of the toxins. Moreover, for C2 toxin, we demonstrated that EGA inhibits the pH-dependent transport of the A component across cell membranes. EGA is not cytotoxic, and therefore, we propose it as a lead compound for the development of novel pharmacological inhibitors against clostridial binary actin ADP-ribosylating toxins.
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany. leonie.schnell@uni-ulm.de.
authors.forename: Leonie
authors.initials: L
authors.lastname: Schnell
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany. ann-katrin.mittler@uni-ulm.de.
authors.forename: Ann-Katrin
authors.initials: AK
authors.lastname: Mittler
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany. mirko.sadi@uni-ulm.de.
authors.forename: Mirko
authors.initials: M
authors.lastname: Sadi
authors.affiliation: Department of Anaerobic Bacteria, Pasteur Institute, 75015 Paris, France. michel-robert.popoff@pasteur.fr.
authors.forename: Michel R
authors.initials: MR
authors.lastname: Popoff
authors.affiliation: Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany. carsten.schwan@pharmakol.uni-freiburg.de.
authors.forename: Carsten
authors.initials: C
authors.lastname: Schwan
authors.affiliation: Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany. klaus.aktories@pharmakol.uni-freiburg.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Aktories
authors.affiliation: Department of Chemical Sciences, University of Padova, 35121 Padova, Italy. andrea.mattarei@unipd.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mattarei
authors.affiliation: Department of Biomedical Sciences, University of Padova, 35121 Padova, Italy. doazte@gmail.com.
authors.forename: Domenico
authors.initials: D
authors.lastname: Azarnia Tehran
authors.affiliation: Department of Biomedical Sciences, University of Padova, 35121 Padova, Italy. cesare.montecucco@gmail.com.
authors.forename: Cesare
authors.initials: C
authors.lastname: Montecucco
authors.affiliation: Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany. holger.barth@uni-ulm.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Barth
mesh_terms: D036002:ADP Ribose Transferases / Q000633:toxicity*; D000199:Actins / Q000378:metabolism; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000633:toxicity*; D001427:Bacterial Toxins / Q000633:toxicity*; D001905:Botulinum Toxins / Q000633:toxicity*; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D021381:Protein Transport / Q000187:drug effects; D012664:Semicarbazones / Q000494:pharmacology*; D014709:Vero Cells
chemical_list: D000199:Actins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D012664:Semicarbazones; C050737:iota toxin, Clostridium perfringens; D000246:Adenosine Diphosphate Ribose; D036002:ADP Ribose Transferases; C410164:actin-specific ADP-ribosyltransferase, Clostridium; D001905:Botulinum Toxins; C096324:botulinum toxin type C
keywords: Clostridium botulinum C2 toxin; Clostridium difficile CDT; Clostridium perfringens iota toxin; EGA; binary toxin