부산대학교 도서관

Subspecies of the protozoan parasite Trypanosoma brucei are the causative agents of Human African Trypanosomiasis (HAT), a debilitating neglected tropical disease prevalent across sub-Saharan Africa. HAT case numbers have steadily decreased since the start of the century, and sustainable elimination of one form of the disease is in sight. However, key to this is the development of novel drugs to combat the disease. Acoziborole is a recently developed benzoxaborole, currently in advanced clinical trials, for treatment of stage 1 and stage 2 HAT. Importantly, acoziborole is orally bioavailable, and curative with one dose. Recent studies have made significant progress in determining the molecular mode of action of acoziborole. However, less is known about the potential mechanisms leading to acoziborole resistance in trypanosomes. In this study, an in vitro-derived acoziborole-resistant cell line was generated and characterised. The AcoR line exhibited significant cross-resistance with the methyltransferase inhibitor sinefungin as well as hypersensitisation to known trypanocides. Interestingly, transcriptomics analysis of AcoR cells indicated the parasites had obtained a procyclic- or stumpy-like transcriptome profile, with upregulation of procyclin surface proteins as well as differential regulation of key metabolic genes known to be expressed in a life cycle-specific manner, even in the absence of major morphological changes. However, no changes were observed in transcripts encoding CPSF3, the recently identified protein target of acoziborole. The results suggest that generation of resistance to this novel compound in vitro can be accompanied by transcriptomic switches resembling a procyclic- or stumpy-type phenotype. Author summary: Human African Trypanosomiasis (HAT), also known as Sleeping Sickness, is a parasitic disease prevalent across sub-Saharan Africa, where it is transmitted by blood-sucking Tsetse flies. The disease is caused by a single-celled protozoan parasite called Trypanosoma brucei. HAT case numbers have decreased over the past two decades, and elimination is in sight. However, to meet the WHO objective of sustainable HAT elimination, newer and safer drugs are needed. Acoziborole is a new drug that has proven safe and effective against HAT and, unlike previous drugs, it can be orally administered. Whilst the mode of action of acoziborole was recently identified, less is known regarding the mechanisms by which T. brucei could become resistant to acoziborole. To address this, we generated a drug resistant cell line under laboratory conditions, in order to analyse the differences between resistant and sensitive cells. By sequencing the transcriptome, we observed that many genes associated with mammalian-infective parasites are down-regulated, whilst genes associated with the insect stage are up-regulated. As a result of these differences, the metabolic effects of acoziborole on parasites are nullified. These data suggest that parasite differentiation, albeit on a gene expression level, is potentially a mechanism of drug resistance in T. brucei, although it is doubtful whether this mechanism could occur in the field where mammalian immune effectors would destroy parasites differentiating this way. [ABSTRACT FROM AUTHOR]