title: N-chlorotaurine, a long-lived oxidant produced by human leukocytes, inactivates Shiga toxin of enterohemorrhagic Escherichia coli.
abstract: N-chlorotaurine (NCT), the main representative of long-lived oxidants produced by granulocytes and monocytes, is known to exert broad-spectrum microbicidal activity. Here we show that NCT directly inactivates Shiga toxin 2 (Stx2), used as a model toxin secreted by enterohemorrhagic Escherichia coli (EHEC). Bacterial growth and Stx2 production were both inhibited by 2 mM NCT. The cytotoxic effect of Stx2 on Vero cells was removed by ≥5.5 mM NCT. Confocal microscopy and FACS analyses showed that the binding of Stx2 to human kidney glomerular endothelial cells was inhibited, and no NCT-treated Stx2 entered the cytosol. Mass spectrometry displayed oxidation of thio groups and aromatic amino acids of Stx2 by NCT. Therefore, long-lived oxidants may act as powerful tools of innate immunity against soluble virulence factors of pathogens. Moreover, inactivation of virulence factors may contribute to therapeutic success of NCT and novel analogs, which are in development as topical antiinfectives.
authors.affiliation: Department of Hygiene, Microbiology and Social Medicine, Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Eitzinger
authors.forename: Silvia
authors.initials: S
authors.lastname: Ehrlenbach
authors.forename: Herbert
authors.initials: H
authors.lastname: Lindner
authors.forename: Leopold
authors.initials: L
authors.lastname: Kremser
authors.forename: Waldemar
authors.initials: W
authors.lastname: Gottardi
authors.forename: Dmitri
authors.initials: D
authors.lastname: Debabov
authors.forename: Mark
authors.initials: M
authors.lastname: Anderson
authors.forename: Markus
authors.initials: M
authors.lastname: Nagl
authors.forename: Dorothea
authors.initials: D
authors.lastname: Orth
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002522:Chlorocebus aethiops; D004591:Electrophoresis, Polyacrylamide Gel; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D054324:Enterohemorrhagic Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D007678:Kidney Glomerulus / Q000166:cytology; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism*; D013058:Mass Spectrometry; D008954:Models, Biological; D008969:Molecular Sequence Data; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D022641:Shiga Toxin 2 / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D013654:Taurine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014709:Vero Cells
chemical_list: C573019:N-monochloro-2,2-dimethyltaurine; D016877:Oxidants; D022641:Shiga Toxin 2; D013654:Taurine; C043410:N-chlorotaurine; C560851:NVC-422