Decoding the Anti-Trypanosoma cruzi Action of HIV Peptidase Inhibitors Using Epimastigotes as a Model

Abstract

BackgroundAspartic peptidase inhibitors have shown antimicrobial action against distinct microorganisms. Due to an increase in the occurrence of Chagas' disease/AIDS co-infection, we decided to explore the effects of HIV aspartic peptidase inhibitors (HIV-PIs) on Trypanosoma cruzi, the etiologic agent of Chagas' disease.Methodology and Principal FindingsHIV-PIs presented an anti-proliferative action on epimastigotes of T. cruzi clone Dm28c, with IC50 values ranging from 0.6 to 14 µM. The most effective inhibitors, ritonavir, lopinavir and nelfinavir, also had an anti-proliferative effect against different phylogenetic T. cruzi strains. The HIV-PIs induced some morphological alterations in clone Dm28c epimastigotes, as reduced cell size and swollen of the cellular body. Transmission electron microscopy revealed that the flagellar membrane, mitochondrion and reservosomes are the main targets of HIV-PIs in T. cruzi epimastigotes. Curiously, an increase in the epimastigote-into-trypomastigote differentiation process of clone Dm28c was observed, with many of these parasites presenting morphological alterations including the detachment of flagellum from the cell body. The pre-treatment with the most effective HIV-PIs drastically reduced the interaction process between epimastigotes and the invertebrate vector Rhodnius prolixus. It was also noted that HIV-PIs induced an increase in the expression of gp63-like and calpain-related molecules, and decreased the cruzipain expression in epimastigotes as judged by flow cytometry and immunoblotting assays. The hydrolysis of a cathepsin D fluorogenic substrate was inhibited by all HIV-PIs in a dose-dependent manner, showing that the aspartic peptidase could be a possible target to these drugs. Additionally, we verified that ritonavir, lopinavir and nelfinavir reduced drastically the viability of clone Dm28c trypomastigotes, causing many morphological damages.Conclusions and SignificanceThe results contribute to understand the possible role of aspartic peptidases in T. cruzi physiology, adding new in vitro insights into the possibility of exploiting the use of HIV-PIs in the clinically relevant forms of the parasite.

Effects of a novel β–lapachone derivative on Trypanosoma cruzi : Parasite death involving apoptosis, autophagy and necrosis

“…Nevertheless it may furnish significant insights for the infection chemotherapy, as β-lapachone was reported to produce similar alterations in T. cruzi epimastigotes, amastigotes and trypomastigotes (Docampo et al., 1978), the developmental forms that multiply within mammalian host cells and spread via blood, respectively. In addition, different antiparasitic compounds may display similar effects upon epimastigotes and trypomastigotes and/or amastigotes, the developmental forms (Urbina et al., 1988, Urbina et al., 1993; Moreira et al., 2013a; Costa et al., 2011, Azeredo et al., 2014, Díaz et al., 2014; Jimenez et al., 2014; Veiga-Santos et al., 2014, Britta et al., 2015, Meira et al., 2015, Volpato et al., 2015, Beer et al., 2016) and the epimastigotes may therefore comprise and/or take part in experimental models (Kessler et al., 2013, Benítez et al., 2014, Sangenito et al., 2014, Wong-Baeza et al., 2015, Khare et al., 2015, Pessoa et al., 2016, Valera Vera et al., 2016). Thus, numerous studies perform screening experiments with epimastigotes and/or trypomastigotes further approach the selected active compounds in intracellular amastigotes (e.g.…”

Lopinavir, an HIV-1 peptidase inhibitor, induces alteration on the lipid metabolism ofLeishmania amazonensispromastigotes

“…Then, cells were washed in the same buffer, dehydrated in acetone and embedded in Epon. Ultrathin sections were mounted on 300-mesh grids, stained with uranyl acetate and lead citrate and observed under a Zeiss 900 TEM (Zeiss, Oberkochen, Germany) (Santos et al , 2009 ; Sangenito et al , 2014 ).…”

Crystal structure of the retroviral protease‐like domain of a protozoal DNA damage‐inducible 1 protein

“…The width of the cavity thus formed is approximately 24 A measured between the Ca atom of Gln269 of the two subunits. The cavity of LmDdi1-RVP is bigger than that formed in HIV-1 PR, which has a width of approximately [19][20][21][22] A in the open form. In HIV-1 PR, as the dimer is symmetric, the same residues form S1 and S1 0 subsites for the P1 and P1 0 positions of the substrate, respectively.…”