Molecular characterization of cytosolic and mitochondrial tryparedoxin peroxidase in Trypanosoma cruzi populations susceptible and resistant to benznidazole

Abstract

Antioxidant defense in Trypanosomatids has been indicated as a potential target for chemotherapy. Tryparedoxin peroxidase (TXNPx) participates in this defense by metabolizing hydrogen peroxide to water molecules. In this work, genes encoding both cytosolic (cTcTXNPx) and mitochondrial (mTcTXNPx) TXNPx were characterized in 15 benznidazole-susceptible and resistant Trypanosoma cruzi strains. Northern blot and real-time RT-PCR analyses revealed that the levels of cTcTXNPx and mTcTXNPx mRNA were two-fold higher in the in-vitro-induced resistant 17 LER T. cruzi population than its drug-susceptible counterpart 17 WTS. The mRNA levels for both genes were similar among the other T. cruzi samples studied. No amplification of these genes was observed in the parasite genome. In silico analyses indicated that cTcTXNPx and mTcTXNPx genes present eight and two copies, respectively, dispersed in the parasite genome. By western blot analysis, anti-cTcTXNPx and anti-mTcTXNPx polyclonal antibodies recognized a 23- and 25-kDa peptide, respectively, in all T. cruzi samples analyzed. The expression levels of these native proteins were similar for all samples except 17 LER, which displayed two-fold greater expression. In addition, the oxidized mTcTXNPx protein (50 kDa) demonstrated 5.5-fold greater expression in the 17 LER population than 17 WTS. Our findings demonstrate increased expression of the cytosolic and mitochondrial TcTXNPx in the T. cruzi population with in-vitro-induced resistance to benznidazole.

Intraspecies Variation in Trypanosoma cruzi GPI-Mucins: Biological Activities and Differential Expression of α-Galactosyl Residues

“…66 Many molecular studies have compared those two populations to identify resistance markers. [67][68][69] Although no correlation was detected, other studies have found differences in the in vitroinduced BZ-resistant strains (17WTS X 17LER). 67 More recently, a proteomic analysis of BZS-Y/BZR-Y and 17WTS/ 17LER also identified many overexpressed proteins in the BZR-Y population.…”

Comparative Transcriptomic and Proteomic Analyses of Trichomonas vaginalis following Adherence to Fibronectin

“…In Leishmania donovani, not only is TXNPx crucial for survival during oxidative stress, it also enhances infectivity (69). For Trypanosoma cruzi, there is increasing evidence showing that antioxidant enzymes are critical for immune evasion by protecting the parasite from macrophage-derived reactive oxygen species (ROS) (56). In addition, the expression level of thioredoxin peroxidase (spot 33) (TVAG_484570) increased ϳ1.9-fold.…”

Molecular characterization of Cyclophilin (TcCyP19) in Trypanosoma cruzi populations susceptible and resistant to benznidazole

“…Interestingly, the deletion of copies of genes encoding two different nitroreductases, namely, old yellow enzyme (TcOYE; also named prostaglandin synthase or NADPH oxidoreductase) and trypanosomal type I nitroreductase (NTR-1) (Wilkinson et al, 2008), has been associated with a phenotype of T. cruzi, which is resistant to NFX and BZ in vitro. Overexpression of enzymatic activity related to antioxidant response, like that of tryparedoxin peroxidase, ascorbate peroxidase, and iron-superoxide dismutase, has been detected in T. cruzi populations resistant to BZ (Nogueira et al, 2006(Nogueira et al, , 2009(Nogueira et al, , 2012. In addition, the hexose transporter activity was 40% lower in a BZ-resistant T. cruzi population than in the susceptible control (dos Santos et al, 2012).…”