Pentamidine antagonizes the anti-T. cruzi effect of benznidazole in vitro and in vivo: implications about the polyamine transport as a trypanocidal target

SEGUEL, VERÓNICA; CASTRO. LORENA; REIGADA, CHANTAL; CORTES, LEONEL; DIAZ, MARIA; MIRANDA, MARIANA; PEREIRA, CA; LAPIER, MICHEL; CAMPOS-ESTRADA, C; MAYA, JUAN; MORELLO, ANTONIO; KEMMERLING, ULRIKE; LOPEZ-MUÑOZ, RODRIGO

EXPERIMENTAL PARASITOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2016

0014-4894

Benznidazole is the first-line drug used in treating Chagas disease, which is caused by the parasiteTrypanosoma cruzi (T. cruzi). However, benznidazole has limited efficacy and several adverse reactions.Pentamidine is an antiprotozoal drug used in the treatment of leishmaniasis and African trypanosomiasis.In T. cruzi, pentamidine blocks the transport of putrescine, a precursor of trypanothione, whichconstitutes an essential molecule in the resistance of T. cruzi to benznidazole. In the present study, wedescribe the effect of the combination of benznidazole and pentamidine on isolated parasites,mammalian cells and in mice infected with T. cruzi. In isolated trypomastigotes, we performed a dosematrixscheme of combinations, where pentamidine antagonized the effect of benznidazole, mainly atconcentrations below the EC50 of pentamidine. In T. cruzi-infected mammalian cells, pentamidinereversed the effect of benznidazole (measured by qPCR). In comparison, in infected BALB/c mice, pentamidinefailed to get synergy with benznidazole, measured on mice survival, parasitemia and amastigotenest quantification. To further explain the in vitro antagonism, we explored whether pentamidine affectsintracellular trypanothione levels, however, pentamidine produced no change in trypanothione concentrations.Finally, the T. cruzi polyamine permease (TcPAT12) was overexpressed in epimastigotes,showing that pentamidine has the same trypanocidal effect, independently of transporter expressionlevels. These results suggest that, in spite of the high potency in the putrescine transport blockade,TcPAT12 permease is not the main target of pentamidine, and could explain the lack of synergism betweenpentamidine and benznidazole.