Author/Editor		Benítez, Diego; Medeiros, Andrea; Panozzo-Zenere, Esteban A.; Prousis, Kyriakos C.; Roussaki, Marina; Calogeropoulou, Theodora; Detsi, Anastasia; Jaeger, Timo; Šaraluskas, Jonas; Peterlin-Mašič, Lucija; Kunick, Conrad; Labadie, Guillermo R.; Flohé, Leopold; Comini, Marcelo A.
Title		Identification of novel chemical scaffolds inhibiting trypanothione synthetase from pathogenic trypanosomatids
Type		članek
Vol. and No.		Letnik 10, št. 4
Publication year		2016
Volume		str. 1-25
ISSN		1935-2727 - PLoS neglected tropical diseases
Language		eng
Abstract		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. 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 M 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 = microM ), respectively. A bis-benzyl diamine derivative and MOL2008 depleted intracellular trypanothione in treated parasites, which confirmed the on-target activity of these compounds. 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.
Keywords		parasitic diseases drug metabolism Trypanosoma brucei enzyme inhibitors colorimetric assays