Lopinavir and Nelfinavir Induce the Accumulation of Crystalloid Lipid Inclusions within the Reservosomes of Trypanosoma cruzi and Inhibit Both Aspartyl-Type Peptidase and Cruzipain Activities Detected in These Crucial Organelles

Abstract

Several research groups have explored the repositioning of human immunodeficiency virus aspartyl peptidase inhibitors (HIV-PIs) on opportunistic infections caused by bacteria, fungi and protozoa. In Trypanosoma cruzi, HIV-PIs have a high impact on parasite viability, and one of the main alterations promoted by this treatment is the imbalance in the parasite’s lipid metabolism. However, the reasons behind this phenomenon are unknown. In the present work, we observed by transmission electron microscopy (TEM) that the treatment of T. cruzi epimastigotes with the HIV-PIs lopinavir and nelfinavir induced a huge accumulation of crystalloid-shaped lipids within the reservosomes, most of them deforming these key organelles. As previously reported, those structures are characteristic of lipid inclusions formed mostly of cholesterol and cholesterol-esters. The fractionation of nontreated epimastigotes generated two distinct fractions enriched in reservosomes: one mostly composed of lipid inclusion-containing reservosomes (Fraction B1) and one where lipid inclusions were much less abundant (Fraction B2). Interestingly, the extract of Fraction B2 presented enzymatic activity related to aspartyl-type peptidases 3.5 times higher than that found in the extract obtained from Fraction B1. The cleavage of cathepsin D substrate by this class of peptidases was strongly impaired by pepstatin A, a prototypical aspartyl PI, and the HIV-PIs lopinavir and nelfinavir. In addition, both HIV-PIs also inhibited (to a lesser extent) the cruzipain activity present in reservosomes. Finally, our work provides new evidence concerning the presence and supposed participation of aspartyl peptidases in T. cruzi, even as it adds new information about the mechanisms behind the alterations promoted by lopinavir and nelfinavir in the protozoan.

Lopinavir-menthol co-crystals for enhanced dissolution rate and intestinal absorption

“…Lopinavir exhibited an inhibition of growth of some fungal cells and has potential effect as a therapy for fungal infections [ 8 , 9 ]. In addition, lopinavir has been investigated as a treatment plan for some parasitic infections [ 10 , 11 ]. Recently, Lopinavir has been evaluated alone or in combination with ritonavir in the treatment of COVID patients, but limited success has been shown [ [12] , [13] , [14] , [15] ].…”

Fexinidazole interferes with the growth and structural organization of Trypanosoma cruzi

“…According to Pereira et al, the cultivation of epimastigotes with a medium supplemented with 50% fetal calf serum caused the formation of lipid inclusions of different shapes in the reservosomes 15 . The accumulation www.nature.com/scientificreports/ of lipid content leading to the deformation of reservosomes on Y strain epimastigotes was also caused by treatment with lopinavir and nelfinavir, which promote an imbalance in proteolysis and lipid storage, and might inhibit parasite aspartyl peptidases 22 . Several authors have also reported disorganization of reservosomes due to different drug treatments.…”

Fexinidazole interferes with the growth and structural organization of Trypanosoma cruzi

“…According to Pereira et al 2011, the cultivation of epimastigotes with a medium supplemented with 50% fetal calf serum caused the formation of lipid inclusions of different shapes in the reservosomes 23 . The accumulation of lipid content leading to the deformation of reservosomes on Y strain epimastigotes was also caused by treatment with lopinavir and nel navir 24 .…”