Trypanothione synthetase contributes to parasite survival towards oxidative stress and trypanocidal drugs benznidazol and nifurtimox in Trypanosoma cruzi

MESIAS AC; SASONI N; ARIAS DG; PEREZ BRANDAN C; ORBAN OCF; KUNICK C; ROBELLO C; COMINI MA; GARG NJ; ZAGO MP

Caxambu, Minas Gerais

Congreso; XXXIV Meeting of the Brazilian Society of Protozoology/XLIV Annual Meeting on Basic Research in Chagas disease; 2018

Sociedade Brasileira de Protozoologia

The antioxidant network of Trypanosoma cruzi is known to be determinant in its survival upon the oxidative response displayed by innate immunity cells, and thereby allow the establishment of the infection. Besides, some members of this system are promising targets for the development of new treatment strategies for Chagas disease since they are trypanosomatid-specific enzymes, absent in the vertebrate host. One of these, named trypanothione synthetase (TryS), mediates biosynthesis of a low MW thiol formed by spermidine and two molecules of glutathione, called trypanothione. This metabolite is extremely important for the recycling of antioxidant oxidoreductases and the neutralization of ROS in the parasite cell. We have overexpressed TryS in T. cruzi SylvioX10 strain, recombinant parasites (TryShi) exhibited stable overexpression (>2-fold increase) of the TryS protein and a significant increase in TryS enzymatic activity as compared to controls. Herein we report that TryShi epimastigotes as well as infective trypomastigote forms, exhibited higher resistance to H2O2 (50-1000mM), compared to wild type parasites (36-71%, respectively). Even more, epimastigote and trypomastigote forms of TryShi (vs. control) tolerated higher doses of benznidazole and nifurtimox, the drugs currently administered for acute Chagas disease treatment. Further, treatment with TryS specific inhibitors (5-30 mM) was beneficial in increasing parasite?s sensitivity to anti-parasitic drugs. Our results firstly suggest that TryS provides a sort of benefit to the pathogen to develop resistance against currently used anti-trypanosomal drugs and secondly, its inhibition could be useful for the design of drug combination therapy against Chagas disease.