Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects 5–8 million people in Latin America. Although the nitroheterocyclic compound benznidazole has been the front-line drug for several decades, treatment failures are common. Benznidazole is a pro-drug and is bio-activated within the parasite by the mitochondrial nitroreductase TcNTR-1, leading to the generation of reactive metabolites that have trypanocidal activity. To better assess drug action and resistance, we sequenced the genomes of T. cruzi Y strain (35.5 Mb) and three benznidazole-resistant clones derived from a single drug-selected population. This revealed the genome-wide accumulation of mutations in the resistant parasites, in addition to variations in DNA copy-number. We observed mutations in DNA repair genes, linked with increased susceptibility to DNA alkylating and inter-strand cross-linking agents. Stop-codon-generating mutations in TcNTR-1 were associated with cross-resistance to other nitroheterocyclic drugs. Unexpectedly, the clones were also highly resistant to the ergosterol biosynthesis inhibitor posaconazole, a drug proposed for use against T. cruzi infections, in combination with benznidazole. Our findings therefore identify the highly mutagenic activity of benznidazole metabolites in T. cruzi, demonstrate that this can result in multi-drug resistance, and indicate that vigilance will be required if benznidazole is used in combination therapy.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): BAS/1/1020–01–01
Acknowledgements: M.C.C. was funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil. J.M.K. acknowledges financial support from the British Heart Foundation (Grant PG/13/88/30556) and the Drugs for Neglected Diseases initiative (DNDi). M.D.L. is supported by an EU Marie Curie Fellowship. J.P. is funded by a UK BBSRC LiDO PhD studentship. T.G.C. is funded by the UK MRC (Grant no. MR/K000551/1, MR/M01360X/1, MR/N010469/1). The authors would like to thank members of KAUST Bioscience Core Sequencing facility for sequencing the parasites. This part of the work was funded by Faculty baseline funding (BAS/1/1020–01–01) to A.P. We thank Arkady Mustaev (New Jersey Medical School –Rutgers) for kindly providing BODIPY conjugated posaconazole,