Crystal violet structural analogues identified by in silico drug repositioning present anti-Trypanosoma cruzi activity through inhibition of proline transporter TcAAAP069.

Melisa Sayé,Mariana R. Miranda,Edward Valera-Vera,Chantal Reigada,Lucrecia Gauna,Claudio A. Pereira,Igor C. Almeida

doi:10.1371/journal.pntd.0007481

Melisa Sayé, Mariana R. Miranda + Show 5 more

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https://doi.org/10.1371/journal.pntd.0007481

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Abstract

BackgroundCrystal violet (CV) was used for several years in blood banks to eliminate the parasite Trypanosoma cruzi in endemic areas in order to prevent transfusion-transmitted Chagas disease. One mechanism of action described for CV involves inhibition of proline uptake. In T. cruzi, proline is essential for host cell infection and intracellular differentiation among other processes, and can be obtained through the proline permease TcAAAP069.Methodology/Principal findingsCV inhibited proline transporter TcAAAP069 and parasites overexpressing this permease were 47-fold more sensitive to this compound than control parasites. Using CV as reference molecule, loratadine, cyproheptadine, olanzapine and clofazimine were identified as structurally related compounds to CV (structural analogues) by in silico drug repurposing through a similarity-based virtual screening protocol. All these already-approved drugs for clinical use inhibited TcAAAP069 activity with different efficacies and also presented trypanocidal action in epimastigotes, trypomastigotes and amastigotes of the Y, CL Brener and Dm28c T. cruzi strains. Finally, a synergistic effect between benznidazole and the CV chemical analogues was evidenced by combination and dose-reduction indexes values in epimastigotes and trypomastigotes of the Y strain.Conclusions/SignificanceLoratadine, cyproheptadine and clofazimine inhibit TcAAAP069 proline transporter and also present trypanocidal effect against all T. cruzi life stages in strains from three different DTUs. These CV structural analogues could be a starting point to design therapeutic alternatives to treat Chagas disease by finding new indications for old drugs. This approach, called drug repurposing is a recommended strategy by the World Health Organization to treat neglected diseases, like Chagas disease, and combination therapy may improve the possibility of success of repositioned drugs.

Highlights

Chagas disease is a neglected disease caused by the protozoan parasite Trypanosoma cruzi that can be mainly acquired through an insect vector, blood transfusion, placental or congenital transmission and consumption of contaminated food [1,2]
In this work we first demonstrate that Crystal violet (CV) has the proline permease TcAAAP069 as one of its molecular targets
We search in a database of already-approved drugs for compounds that were structurally related to CV under the premise “similar structure, similar activity”

Summary

Introduction

Chagas disease is a neglected disease caused by the protozoan parasite Trypanosoma cruzi that can be mainly acquired through an insect vector, blood transfusion, placental or congenital transmission and consumption of contaminated food [1,2]. Among these mechanisms, blood transfusion is still an important mechanism of transmission of Chagas disease due to lack of blood bank control and migration of people from endemic to non-endemic countries [3,4]. Crystal violet (CV) was used for several years in blood banks to eliminate the parasite Trypanosoma cruzi in endemic areas in order to prevent transfusion-transmitted Chagas disease. In T. cruzi, proline is essential for host cell infection and intracellular differentiation among other processes, and can be obtained through the proline permease TcAAAP069

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