Benznidazole biotransformation and multiple targets in Trypanosoma cruzi revealed by metabolomics.
BACKGROUND
The first line treatment for Chagas disease, a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, involves administration of benznidazole (Bzn). Bzn is a 2-nitroimidazole pro-drug which requires nitroreduction to become active, although its mode of action is not fully understood. In the present work we used a non-targeted MS-based metabolomics approach to study the metabolic response of T. cruzi to Bzn.


RESULTS
Parasites treated with Bzn were minimally altered compared to untreated trypanosomes, although the redox active thiols trypanothione, homotrypanothione and cysteine were significantly diminished in abundance post-treatment. In addition, multiple Bzn-derived metabolites were detected after treatment. These metabolites included reduction products, fragments and covalent adducts of reduced Bzn linked to each of the major low molecular weight thiols: trypanothione, glutathione, γ-glutamylcysteine, glutathionylspermidine, cysteine and ovothiol A. Bzn products known to be generated in vitro by the unusual trypanosomal nitroreductase, TcNTRI, were found within the parasites, but low molecular weight adducts of glyoxal, a proposed toxic end-product of NTRI Bzn metabolism, were not detected.


CONCLUSIONS
Our data is indicative of a major role of the thiol binding capacity of Bzn reduction products in the mechanism of Bzn toxicity against T. cruzi.
Unidad de Biología Molecular, Institut Pasteur de Montevideo, Montevideo, Uruguay.
Andrea
A
Trochine
The Wellcome Trust Centre for Molecular Parasitology, Institute for Infection, Immunity and Inflammation and Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia.
Darren J
DJ
Creek
Unidad de Biología Molecular, Institut Pasteur de Montevideo, Montevideo, Uruguay.
Paula
P
Faral-Tello
The Wellcome Trust Centre for Molecular Parasitology, Institute for Infection, Immunity and Inflammation and Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Michael P
MP
Barrett
Unidad de Biología Molecular, Institut Pasteur de Montevideo, Montevideo, Uruguay; Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
Carlos
C
Robello
D001711:Biotransformation; D005978:Glutathione / Q000378:metabolism; D013058:Mass Spectrometry; D053858:Metabolic Networks and Pathways; D055442:Metabolome / Q000187:drug effects*; D055432:Metabolomics; D009593:Nitroimidazoles / Q000378:metabolism* / Q000494:pharmacology*; D014349:Trypanosoma cruzi / Q000187:drug effects* / Q000378:metabolism*
D009593:Nitroimidazoles; D005978:Glutathione; C009999:benzonidazole