title: HIV aspartic peptidase inhibitors are effective drugs against the trypomastigote form of the human pathogen Trypanosoma cruzi.
abstract: There is a general lack of effective and non-toxic chemotherapeutic agents against Chagas' disease despite more than a century of research. In this regard, we have verified the impact of human immunodeficiency virus aspartic peptidase inhibitors (HIV-PIs) on the viability and morphology of infective trypomastigote forms of Trypanosoma cruzi as well as on the aspartic peptidase and proteasome activities produced by this parasite. The effects of HIV-PIs on viability were assessed by counting motile parasites in a Neubauer chamber. Morphological alterations were detected by light microscopy of Giemsa-stained smears and scanning electron microscopy. Modulation of aspartic peptidase and proteasome activities by the HIV-PIs was measured by cleavage of fluorogenic peptide substrates. The majority of the HIV-PIs (6/9) were able to drastically decrease the viability of trypomastigotes after 4 h of treatment, with nelfinavir and lopinavir being the most effective compounds presenting LD50 values of 8.6 µM and 10.6 µM, respectively. Additionally, both HIV-PIs were demonstrated to be effective in a time- and cell density-dependent manner. Treatment with nelfinavir and lopinavir caused many morphological/ultrastructural alterations in trypomastigotes; parasites became round in shape, with reduced cell size and flagellar shortening. Nelfinavir and lopinavir were also capable of significantly inhibiting the aspartic peptidase and proteasome activities measured in trypomastigote extracts. These results strengthen the data on the positive effects of HIV-PIs on parasitic infections, possibly by targeting the parasite aspartic peptidase(s) and proteasome(s), opening a new possibility for the use of these clinically approved drugs as an alternative chemotherapy to treat Chagas' disease.
authors: Laboratório de Investigação de Peptidases, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
authors: Leandro S
authors: LS
authors: Sangenito
authors: Laboratório de Investigação de Peptidases, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil; Programa de Pós-Graduação em Bioquímica, Instituto de Química, UFRJ, Rio de Janeiro, Brazil.
authors: Diego S
authors: DS
authors: Gonçalves
authors: Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, Brazil.
authors: Sergio H
authors: SH
authors: Seabra
authors: Laboratório de Estudos Integrados em Protozoologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil.
authors: Claudia M
authors: CM
authors: d'Avila-Levy
authors: Laboratório de Investigação de Peptidases, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil; Programa de Pós-Graduação em Bioquímica, Instituto de Química, UFRJ, Rio de Janeiro, Brazil. Electronic address: andre@micro.ufrj.br.
authors: André L S
authors: AL
authors: Santos
authors: Laboratório de Investigação de Peptidases, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil. Electronic address: mbranquinha@micro.ufrj.br.
authors: Marta H
authors: MH
authors: Branquinha
mesh_terms: D000981:Antiprotozoal Agents / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D008124:Locomotion / Q000187:drug effects; D008853:Microscopy; D014349:Trypanosoma cruzi / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D014352:Trypanosomiasis / Q000188:drug therapy / Q000469:parasitology*
chemical_list: D000981:Antiprotozoal Agents; D017320:HIV Protease Inhibitors
keywords: Aspartic peptidase; HIV peptidase inhibitor; Morphological alterations; Proteasome; Trypanosoma cruzi