Designed azolopyridinium salts block protective antigen pores in vitro and protect cells from anthrax toxin.

Autor: Christoph Beitzinger, Anika Bronnhuber, Kerstin Duscha, Zsuzsanna Riedl, Markus Huber-Lang, Roland Benz, György Hajós, Holger Barth
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: PLoS ONE, Vol 8, Iss 6, p e66099 (2013)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0066099
Popis: BACKGROUND: Several intracellular acting bacterial protein toxins of the AB-type, which are known to enter cells by endocytosis, are shown to produce channels. This holds true for protective antigen (PA), the binding component of the tripartite anthrax-toxin of Bacillus anthracis. Evidence has been presented that translocation of the enzymatic components of anthrax-toxin across the endosomal membrane of target cells and channel formation by the heptameric/octameric PA63 binding/translocation component are related phenomena. Chloroquine and some 4-aminoquinolones, known as potent drugs against Plasmodium falciparium infection of humans, block efficiently the PA63-channel in a dose dependent way. METHODOLOGY/PRINCIPAL FINDINGS: Here we demonstrate that related positively charged heterocyclic azolopyridinium salts block the PA63-channel in the µM range, when both, inhibitor and PA63 are added to the same side of the membrane, the cis-side, which corresponds to the lumen of acidified endosomal vesicles of target cells. Noise-analysis allowed the study of the kinetics of the plug formation by the heterocycles. In vivo experiments using J774A.1 macrophages demonstrated that the inhibitors of PA63-channel function also efficiently block intoxication of the cells by the combination lethal factor and PA63 in the same concentration range as they block the channels in vitro. CONCLUSIONS/SIGNIFICANCE: These results strongly argue in favor of a transport of lethal factor through the PA63-channel and suggest that the heterocycles used in this study could represent attractive candidates for development of novel therapeutic strategies against anthrax.
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