Identification of Novel Chemical Scaffolds Inhibiting Trypanothione Synthetase from Pathogenic Trypanosomatids

Diego Benítez, Andrea Medeiros, Lucía Fiestas, Esteban A. Panozzo-Zenere, Franziska Maiwald, Kyriakos C. Prousis, Marina Roussaki, Theodora Calogeropoulou, Anastasia Detsi, Timo Jaeger, Jonas Šarlauskas, Lucíja Peterlin Mašič, Conrad Kunick, Guillermo R. Labadie, Leopold Flohé, Marcelo A. Comini

Research output: Contribution to journalArticlepeer-review

Abstract

Background: The search for novel chemical entities targeting essential and parasite-specific pathways is considered a priority for neglected diseases such as trypanosomiasis and leishmaniasis. The thiol-dependent redox metabolism of trypanosomatids relies on bis-glutathionylspermidine [trypanothione, T(SH)2], a low molecular mass cosubstrate absent in the host. In pathogenic trypanosomatids, a single enzyme, trypanothione synthetase (TryS), catalyzes trypanothione biosynthesis, which is indispensable for parasite survival. Thus, TryS qualifies as an attractive drug target candidate. Methodology/Principal Finding: A library composed of 144 compounds from 7 different families and several singletons was screened against TryS from three major pathogen species (Trypanosoma brucei, Trypanosoma cruzi and Leishmania infantum). The screening conditions were adjusted to the TryS´ kinetic parameters and intracellular concentration of substrates corresponding to each trypanosomatid species, and/or to avoid assay interference. The screening assay yielded suitable Z’ and signal to noise values (≥0.85 and ~3.5, respectively), and high intra-assay reproducibility. Several novel chemical scaffolds were identified as low μM and selective tri-tryp TryS inhibitors. Compounds displaying multi-TryS inhibition (N,N'-bis(3,4-substituted-benzyl) diamine derivatives) and an N5-substituted paullone (MOL2008) halted the proliferation of infective Trypanosoma brucei (EC50 in the nM range) and Leishmania infantum promastigotes (EC50 = 12 μM), respectively. A bis-benzyl diamine derivative and MOL2008 depleted intracellular trypanothione in treated parasites, which confirmed the on-target activity of these compounds. Conclusions/Significance: Novel molecular scaffolds with on-target mode of action were identified as hit candidates for TryS inhibition. Due to the remarkable species-specificity exhibited by tri-tryp TryS towards the compounds, future optimization and screening campaigns should aim at designing and detecting, respectively, more potent and broad-range TryS inhibitors.

Original languageEnglish (US)
Article numbere0004617
JournalPLoS Neglected Tropical Diseases
Volume10
Issue number4
DOIs
StatePublished - Apr 12 2016
Externally publishedYes

ASJC Scopus subject areas

  • Infectious Diseases
  • Public Health, Environmental and Occupational Health
  • Pharmacology, Toxicology and Pharmaceutics(all)

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