Binding of ε-toxin from Clostridium perfringens in the nervous system

• Published in: Veterinary microbiology 2008-09, Vol.131 (1-2), p.14-25
• Main Authors: Dorca-Arévalo, Jonatan, Soler-Jover, Alex, Gibert, Maryse, Popoff, Michel R, Martín-Satué, Mireia, Blasi, Juan
• Format: Article
• Language: English
• Subjects: animal pathogenic bacteria; Animals; bacterial toxins; Bacterial Toxins - metabolism; Bacterial Toxins - toxicity; binding sites; blood vessels; Blood-Brain Barrier - metabolism; brain; Brain - drug effects; Brain - metabolism; Cattle; central nervous system; central nervous system diseases; chemical bonding; Clostridium perfringens; Clostridium perfringens D; endothelium; enterotoxemia; Enterotoxemia - microbiology; glutamatergic-mediated excitotoxic effect; Glutamic Acid - metabolism; Green Fluorescent Proteins - metabolism; Humans; in vitro studies; Mice; Microscopy, Confocal - veterinary; myelin proteins; Myelin Sheath - metabolism; Nervous System - metabolism; neurotoxicity; neurotoxins; pronase E; Protein Binding; Rats; receptors; Recombinant Fusion Proteins; Sheep; signs and symptoms (animals and humans); Species Specificity; Synaptosomes - metabolism
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2008.02.015

Epsilon-toxin (ε-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. ε-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 ε-toxin, not only in the mouse nervous system but also in the brains of sheep and cattle. An ε-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 ε-toxin to myelin structures. ε-Prototoxin-GFP and ε-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 ε-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 ε-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.