Projects per year
Abstract
Objectives The objective of this study was to identify the mechanisms of resistance to nifurtimox and fexinidazole in African trypanosomes.
Methods Bloodstream-form Trypanosoma brucei were selected for resistance to nifurtimox and fexinidazole by stepwise exposure to increasing drug concentrations. Clones were subjected to WGS to identify putative resistance genes. Transgenic parasites modulating expression of genes of interest were generated and drug susceptibility phenotypes determined.
Results Nifurtimox-resistant (NfxR) and fexinidazole-resistant (FxR) parasites shared reciprocal cross-resistance suggestive of a common mechanism of action. Previously, a type I nitroreductase (NTR) has been implicated in nitro drug activation. WGS of resistant clones revealed that NfxR parasites had lost >100 kb from one copy of chromosome 7, rendering them hemizygous for NTR as well as over 30 other genes. FxR parasites retained both copies of NTR, but lost >70 kb downstream of one NTR allele, decreasing NTR transcription by half. A single knockout line of NTR displayed 1.6- and 1.9-fold resistance to nifurtimox and fexinidazole, respectively. Since NfxR and FxR parasites are ∼6- and 20-fold resistant to nifurtimox and fexinidazole, respectively, additional factors must be involved. Overexpression and knockout studies ruled out a role for a putative oxidoreductase (Tb927.7.7410) and a hypothetical gene (Tb927.1.1050), previously identified in a genome-scale RNAi screen.
Conclusions NTR was confirmed as a key resistance determinant, either by loss of one gene copy or loss of gene expression. Further work is required to identify which of the many dozens of SNPs identified in the drug-resistant cell lines contribute to the overall resistance phenotype.
Original language | English |
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Pages (from-to) | 625-634 |
Number of pages | 10 |
Journal | Journal of Antimicrobial Chemotherapy |
Volume | 71 |
Issue number | 3 |
Early online date | 17 Nov 2015 |
DOIs | |
Publication status | Published - Mar 2016 |
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Dive into the research topics of 'Nitroheterocyclic drug resistance mechanisms in Trypanosoma brucei'. Together they form a unique fingerprint.Projects
- 2 Finished
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A Translational Engine for Biomedical Discoveries (Strategic Grant)
Fairlamb, A. (Investigator) & Gilbert, I. (Investigator)
1/01/13 → 30/09/15
Project: Research
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Aref#d: 18185. Characterization and validation of drug targets in the Kinetoplastida (Principal Research Fellowship/Programme Grant)
Fairlamb, A. (Investigator)
1/10/06 → 30/09/17
Project: Research
Datasets
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Whole Genome Sequencing Variant Call Files for Trypanosoma brucei clones resistant to nifurtimox or fexinidazole
Fairlamb, A. (Creator), Foth, B. (Creator) & Berriman, M. (Creator), University of Dundee, 2015
DOI: 10.15132/10000107
Dataset
File
Profiles
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Fairlamb, Alan
- Biological Chemistry and Drug Discovery - Associate Staff of Biochemistry (Consulting)
Person: Associate Staff