This project focuses on essential proteins from three major global pathogenic protozoa, Trypanosoma brucei, Trypanosoma cruzi and Leishmania species. These are related parasites which cause sleeping sickness, Chagas disease, and leishmaniasis, respectively, and are responsible for tens of millions of infections annually, mainly in the tropical and subtropical areas of the world. These sophisticated protozoa are able to avoid the host defense systems, and cause prolonged suffering for the patients. The few drugs that are available have serious side-effects and drug resistance problems are rising. This proposal addresses the need for developing new therapeutics by targeting a critical biological pathway shared by these eukaryotic organisms. This strategy will facilitate drug development across the three protozoa by using the same inhibitor scaffolds. Specifically, three aminoacyl-tRNA synthetase (aaRS) families that are essential for protein synthesis in living cells will be targeted by integrating structure-based and compound library screening methodologies. The approaches include: (i) """"""""piggyback"""""""" inhibitor development based on known aaRS inhibitors for other pathogens (some of which inhibit trypanosomatids several orders of magnitude better than human cells), (ii) high throughput solution screening of chemical libraries, (iii) fragment cocktail crystallographically, and (iv) computational chemistry. Compound hits will be subjected to rounds of optimization to improve potency and selectivity by structure-based design. Newly synthesized inhibitors will be evaluated by enzyme and cell-based assays to assess efficacy, selectivity and toxicity. The goal of this project is to arrive at one or two submicromolar inhibitors for five of the aaRS enzymes targeted. These would provide new starting points for subsequent drug development efforts.

Public Health Relevance

The research is directly relevant to the development of therapeutic agents for major, yet largely neglected, diseases occurring in tropical and subtropical areas, threatening hundreds of millions of people. Highly potent compounds that selectively inhibit protein synthesis in pathogenic protozoa will be optimized using structure-based drug design methods.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Drug Discovery and Mechanisms of Antimicrobial Resistance Study Section (DDR)
Program Officer
Rogers, Martin J
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University of Washington
Schools of Medicine
United States
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Barros-Álvarez, Ximena; Turley, Stewart; Ranade, Ranae M et al. (2018) The crystal structure of the drug target Mycobacterium tuberculosis methionyl-tRNA synthetase in complex with a catalytic intermediate. Acta Crystallogr F Struct Biol Commun 74:245-254
Devine, William G; Diaz-Gonzalez, Rosario; Ceballos-Perez, Gloria et al. (2017) From Cells to Mice to Target: Characterization of NEU-1053 (SB-443342) and Its Analogues for Treatment of Human African Trypanosomiasis. ACS Infect Dis 3:225-236
Huang, Wenlin; Zhang, Zhongsheng; Ranade, Ranae M et al. (2017) Optimization of a binding fragment targeting the ""enlarged methionine pocket"" leads to potent Trypanosoma brucei methionyl-tRNA synthetase inhibitors. Bioorg Med Chem Lett 27:2702-2707
Barros-Álvarez, Ximena; Kerchner, Keshia M; Koh, Cho Yeow et al. (2017) Leishmania donovani tyrosyl-tRNA synthetase structure in complex with a tyrosyl adenylate analog and comparisons with human and protozoan counterparts. Biochimie 138:124-136
Zhang, Zhongsheng; Koh, Cho Yeow; Ranade, Ranae M et al. (2016) 5-Fluoroimidazo[4,5-b]pyridine Is a Privileged Fragment That Conveys Bioavailability to Potent Trypanosomal Methionyl-tRNA Synthetase Inhibitors. ACS Infect Dis 2:399-404
Huang, Wenlin; Zhang, Zhongsheng; Barros-Álvarez, Ximena et al. (2016) Structure-guided design of novel Trypanosoma brucei Methionyl-tRNA synthetase inhibitors. Eur J Med Chem 124:1081-1092
Pedró-Rosa, Laura; Buckner, Frederick S; Ranade, Ranae M et al. (2015) Identification of potent inhibitors of the Trypanosoma brucei methionyl-tRNA synthetase via high-throughput orthogonal screening. J Biomol Screen 20:122-30
Koh, Cho Yeow; Siddaramaiah, Latha Kallur; Ranade, Ranae M et al. (2015) A binding hotspot in Trypanosoma cruzi histidyl-tRNA synthetase revealed by fragment-based crystallographic cocktail screens. Acta Crystallogr D Biol Crystallogr 71:1684-98
Ranade, Ranae M; Zhang, Zhongsheng; Gillespie, J Robert et al. (2015) Inhibitors of methionyl-tRNA synthetase have potent activity against Giardia intestinalis trophozoites. Antimicrob Agents Chemother 59:7128-31
Koh, Cho Yeow; Kim, Jessica E; Wetzel, Allan B et al. (2014) Structures of Trypanosoma brucei methionyl-tRNA synthetase with urea-based inhibitors provide guidance for drug design against sleeping sickness. PLoS Negl Trop Dis 8:e2775

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