HOW DEHYDROLEUCODINE INDUCES OXIDATIVE STRESS ON Trypanosoma cruzi?

GOMEZ J; GUARISE C; PATRICIA CABALLERO; CIFUENTES D; MASONE D; SOSA MA; BARRERA P

Congreso; XXXIX Reunión Anual de la Sociedad de Biología de Cuyo; 2021

Sociedad de Biología de Cuyo

Trypanosoma cruzi (T. cruzi) is a parasite that causes Chagas disease (CD). The current chemotherapy is based on nitro derivatives, buttheir use is restricted due to the severe side effects, justifying the continuous search for alternative drugs. In this sense, natural compoundsare attractive to study because its low cytotoxicity. T. cruzi has to evade the oxidative response of the host for successful infection andestablishment of the disease. This ability is directly related to its particular antioxidant system based on a reducing molecule: trypanothione-equivalent to glutathione of mammalian cells- and reducing enzymes. Hence, the redox system of the parasite emerges as an attractivetarget for new antiparasitic therapies. In our laboratory, we study the mechanism of action of a natural compound called Dehydroleucodine(DhL). This compound presents an α-methylene group that could block the thiols groups present on trypanothione or reduce enzymes andinduce oxidative stress on the parasite. In this study, we attempted to elucidate the trypanocidal mechanism of action of DhL, focusing onthe parasite antioxidative defense machinery. According to our previous studies, DhL exerted an antiproliferative effect on T. cruzi (IC50:4uM at 24hs), accompanied by a significant increase in reactive oxygen species (ROS) production. In this work, we incubated parasiteswith DhL, observed mitochondrial swelling, and blocked the trypanocidal effect by adding reduced glutathione. To explain these findings,we analyze the possible interaction between DhL/Glutathione and DhL/Trypanothione. We performed simulations of atomistic moleculardynamics with Gromacs of the order of a microsecond. The DhL, Trypanothione and Glutathione molecules were parameterized usingLigParGen and Charmm-GUI. The radial distribution function of the distances between DhL and Glutathione; DhL and Trypanothione didnot show significant differences. The maximum of both curves was ~ 0.6nm (the most frequent distance), and neither of the simulationsshowed a dominant affinity between the molecules. From this analysis, we conclude that DhL exerts a trypanocidal action by the generationof oxidative stress, and this effect is independent of direct interaction with glutathione or trypanothione