Identification of potent inhibitors of the Trypanosoma brucei methionyl-tRNA synthetase via high-throughput orthogonal screening.

Abstract

Improved therapies for the treatment of Trypanosoma brucei, the etiological agent of the neglected tropical disease human African trypanosomiasis, are urgently needed. We targeted T. brucei methionyl-tRNA synthetase (MetRS), an aminoacyl-tRNA synthase (aaRS), which is considered an important drug target due to its role in protein synthesis, cell survival, and its significant differences in structure from its mammalian ortholog. Previous work using RNA interference of MetRS demonstrated growth inhibition of T. brucei, further validating it as an attractive target. We report the development and implementation of two orthogonal high-throughput screening assays to identify inhibitors of T. brucei MetRS. First, a chemiluminescence assay was implemented in a 1536-well plate format and used to monitor adenosine triphosphate depletion during the aminoacylation reaction. Hit confirmation then used a counterscreen in which adenosine monophosphate production was assessed using fluorescence polarization technology. In addition, a miniaturized cell viability assay was used to triage cytotoxic compounds. Finally, lower throughput assays involving whole parasite growth inhibition of both human and parasite MetRS were used to analyze compound selectivity and efficacy. The outcome of this high-throughput screening campaign has led to the discovery of 19 potent and selective T. brucei MetRS inhibitors.

• Authors: Laura Pedró-Rosa, Frederick S Buckner, Ranae M Ranade, Christina Eberhart, Franck Madoux, J Robert Gillespie, Cho Yeow Koh, Steven Brown, Jacqueline Lohse, Christophe L M Verlinde, Erkang Fan, Thomas Bannister, Louis Scampavia, Wim G J Hol, Timothy Spicer, Peter Hodder
• Journal: Journal of biomolecular screening (J Biomol Screen) Vol. 20 Issue 1 Pg. 122-30 (Jan 2015) ISSN: 1552-454X [Electronic] United States
• PMID: 25163684 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: © 2014 Society for Laboratory Automation and Screening.

Chemical References

• Enzyme Inhibitors
• Small Molecule Libraries
• Methionine-tRNA Ligase

Topics

• Cell Line
• Dose-Response Relationship, Drug
• Drug Discovery (methods, standards)
• Drug Evaluation, Preclinical
• Enzyme Inhibitors (pharmacology)
• High-Throughput Screening Assays (methods, standards)
• Humans
• Inhibitory Concentration 50
• Methionine-tRNA Ligase (antagonists & inhibitors)
• Neglected Diseases (drug therapy)
• Small Molecule Libraries
• Trypanosoma brucei brucei (drug effects, enzymology)
• Trypanosomiasis, African (drug therapy)