title: Pentamidine antagonizes the benznidazole's effect in vitro, and lacks of synergy in vivo: Implications about the polyamine transport as an anti-Trypanosoma cruzi target.
abstract: Benznidazole is the first-line drug used in treating Chagas disease, which is caused by the parasite Trypanosoma 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, which constitutes an essential molecule in the resistance of T. cruzi to benznidazole. In the present study, we describe 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 dose-matrix scheme of combinations, where pentamidine antagonized the effect of benznidazole, mainly at concentrations below the EC50of pentamidine. In T. cruzi-infected mammalian cells, pentamidine reversed the effect of benznidazole (measured by qPCR). In comparison, in infected BALB/c mice, pentamidine failed to get synergy with benznidazole, measured on mice survival, parasitemia and amastigote nest quantification. To further explain the in vitro antagonism, we explored whether pentamidine affects intracellular 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 expression levels. 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 between pentamidine and benznidazole.
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Verónica
authors.initials: V
authors.lastname: Seguel
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Lorena
authors.initials: L
authors.lastname: Castro
authors.affiliation: Laboratorio de Parasitología Molecular, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires and CONICET, Buenos Aires, Argentina.
authors.forename: Chantal
authors.initials: C
authors.lastname: Reigada
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Leonel
authors.initials: L
authors.lastname: Cortes
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: María V
authors.initials: MV
authors.lastname: Díaz
authors.affiliation: Laboratorio de Parasitología Molecular, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires and CONICET, Buenos Aires, Argentina.
authors.forename: Mariana R
authors.initials: MR
authors.lastname: Miranda
authors.affiliation: Laboratorio de Parasitología Molecular, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires and CONICET, Buenos Aires, Argentina.
authors.forename: Claudio A
authors.initials: CA
authors.lastname: Pereira
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Michel
authors.initials: M
authors.lastname: Lapier
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Campos-Estrada
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Antonio
authors.initials: A
authors.lastname: Morello
authors.affiliation: Programa de Anatomía y Biología del Desarrollo, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kemmerling
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Juan D
authors.initials: JD
authors.lastname: Maya
authors.affiliation: Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile. Electronic address: rodrigo.lopez@uach.cl.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: López-Muñoz
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000188:drug therapy* / Q000473:pathology; D002522:Chlorocebus aethiops; D016054:DNA, Protozoan / Q000032:analysis / Q000302:isolation & purification; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000031:analogs & derivatives / Q000187:drug effects / Q000378:metabolism; D008264:Macrophages / Q000469:parasitology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009206:Myocardium / Q000473:pathology; D009593:Nitroimidazoles / Q000037:antagonists & inhibitors*; D018512:Parasitemia / Q000188:drug therapy / Q000469:parasitology; D010419:Pentamidine / Q000494:pharmacology*; D011700:Putrescine / Q000378:metabolism; D011897:Random Allocation; D013095:Spermidine / Q000031:analogs & derivatives / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014344:Trypanocidal Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D014349:Trypanosoma cruzi / Q000187:drug effects*; D014709:Vero Cells
chemical_list: D016054:DNA, Protozoan; D009593:Nitroimidazoles; D014344:Trypanocidal Agents; D010419:Pentamidine; C044809:trypanothione; D005978:Glutathione; D013095:Spermidine; D011700:Putrescine; D013936:Thymidine; C009999:benzonidazole
keywords: Benznidazole; Chagas disease; Pentamidine; Polyamine transport; Trypanosoma cruzi