Overexpression of Trypanosoma rangeli trypanothione reductase increases parasite survival under oxidative stress

Abstract

SUMMARYThe infectivity and virulence of pathogenic trypanosomatids are directly associated with the efficacy of their antioxidant system. Among the molecules involved in the trypanosomatid response to reactive oxygen or nitrogen species, trypanothione reductase (TRed) is a key enzyme. In this study, we performed a molecular and functional characterization of the TRed enzyme fromTrypanosoma rangeli(TrTRed), an avirulent trypanosome of mammals. TheTrTRed gene has an open reading frame (ORF) of 1473 bp (~490 aa, 53 kDa) and occurs as a single-copy gene in the haploid genome. The predicted protein contains two oxidoreductase domains, which are equally expressed in the cytosol of epimastigotes and trypomastigotes. Nicotinamide adenine dinucleotide phosphate (NADPH) generation is reduced and endogenous H2O2production is elevated inT. rangeliChoachí strain compared withT. cruziY strain epimastigotes. Oxidative stress induced by H2O2does not induce significant alterations inTrTRed expression. Overexpression ofTrTRed did not influencein vitrogrowth or differentiation into trypomastigotes, but mutant parasites showed increased resistance to H2O2-induced stress. Our results indicate thatT. rangeliconstitutively expresses TRed during the entire life cycle, with reduced levels during infective and non-replicative trypomastigote stages.