Activation of Bicyclic Nitro-drugs by a Novel Nitroreductase (NTR2) in Leishmania

PLoS Pathogens

Susan Wyllie¹  Adam J. Roberts¹  Alan H. Fairlamb¹  Kevin D. Read¹  Stephen Patterson¹  Suzanne Norval¹  Bernardo J. Foth²  Matthew Berriman² 

[1] Division of Biological Chemistry and Drug Discovery, Wellcome Trust Building, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom;Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom

关键词: Promastigotes;    Leishmania donovani;    Drug metabolism;    Parasitic diseases;    Cloning;    Amastigotes;    Leishmania;    Enzyme metabolism;   

DOI  :  10.1371/journal.ppat.1005971

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Drug discovery pipelines for the “neglected diseases” are now heavily populated with nitroheterocyclic compounds. Recently, the bicyclic nitro-compounds (R)-PA-824, DNDI-VL-2098 and delamanid have been identified as potential candidates for the treatment of visceral leishmaniasis. Using a combination of quantitative proteomics and whole genome sequencing of susceptible and drug-resistant parasites we identified a putative NAD(P)H oxidase as the activating nitroreductase (NTR2). Whole genome sequencing revealed that deletion of a single cytosine in the gene for NTR2 that is likely to result in the expression of a non-functional truncated protein. Susceptibility of leishmania was restored by reintroduction of the wild-type gene into the resistant line, which was accompanied by the ability to metabolise these compounds. Overexpression of NTR2 in wild-type parasites rendered cells hyper-sensitive to bicyclic nitro-compounds, but only marginally to the monocyclic nitro-drugs, nifurtimox and fexinidazole sulfone, known to be activated by a mitochondrial oxygen-insensitive nitroreductase (NTR1). Conversely, a double knockout NTR2 null cell line was completely resistant to bicyclic nitro-compounds and only marginally resistant to nifurtimox. Sensitivity was fully restored on expression of NTR2 in the null background. Thus, NTR2 is necessary and sufficient for activation of these bicyclic nitro-drugs. Recombinant NTR2 was capable of reducing bicyclic nitro-compounds in the same rank order as drug sensitivity in vitro. These findings may aid the future development of better, novel anti-leishmanial drugs. Moreover, the discovery of anti-leishmanial nitro-drugs with independent modes of activation and independent mechanisms of resistance alleviates many of the concerns over the continued development of these compound series.

【 授权许可】

CC BY