In vitro effects of tropisetron and granisetron against Echinococcus granulosus (s.s.) protoscoleces by involvement of calcineurin and calmodulin

Mohammad Reza Shiee,Majid Fasihi Harandi,Shahram Nekoeian,Farzaneh Zahabiun,Mahmood Naderi,Eshrat Beigom Kia,Ahmad Reza Dehpour,Elahe Motevaseli

doi:10.1186/s13071-021-04691-9

Abstract

BackgroundCystic echinococcosis (CE) is a disease caused by the larval stage of Echinococcus granulosus sensu lato (s.l.). The treatment of CE mainly relies on the use of benzimidazoles, which can commonly cause adverse side effects. Therefore, more efficient treatment options are needed. Drug repurposing is a useful approach for advancing drug development. We have evaluated the in vitro protoscolicidal effects of tropisetron and granisetron in E. granulosus sensu stricto (s.s.) and assessed the expression of the calcineurin (CaN) and calmodulin (CaM) genes, both of which have been linked to cellular signaling activities and thus are potentially promising targets for the development of drugs.MethodsProtoscoleces (PSC) of E. granulosus (s.s.) (genotype G1) obtained from sheep hepatic hydatid cysts were exposed to tropisetron and granisetron at concentrations of 50, 150 and 250 µM for various periods of time up to 10 days. Cyclosporine A (CsA) and albendazole sulfoxide were used for comparison. Changes in the morphology of PSC were investigated by light microscopy and scanning electron microscopy. Gene expression was assessed using real-time PCR at the mRNA level for E. granulosus calcineurin subunit A (Eg-CaN-A), calcineurin subunit B (Eg-CaN-B) and calmodulin (Eg-CaM) after a 24-h exposure at 50 and 250 µM, respectively.ResultsAt 150 and 250 µM, tropisetron had the highest protoscolicidal effect, whereas CsA was most effective at 50 µM. Granisetron, however, was less effective than tropisetron at all three concentrations. Examination of morphological alterations revealed that the rate at which PSC were killed increased with increasing rate of PSC evagination, as observed in PSC exposed to tropisetron. Gene expression analysis revealed that tropisetron at 50 μM significantly upregulated Eg-CaN-B and Eg-CaM expression while at 250 μM it significantly downregulated both Eg-CaN-B and Eg-CaM expressions; in comparison, granisetron decreased the expression of all three genes at both concentrations.ConclusionsTropisetron exhibited a higher efficacy than granisetron against E. granulosus (s.s.) PSC, which is probably due to the different mechanisms of action of the two drugs. The concentration-dependent effect of tropisetron on calcineurin gene expression might reflect its dual functions, which should stimulate future research into its mechanism of action and evaluation of its potential therapeutical effect in the treatment of CE.Graphical

Highlights

Cystic echinococcosis (CE) is a disease caused by the larval stage of Echinococcus granulosus sensu lato (s.l.)
Human cystic echinococcosis (CE) is a global zoonosis caused by the larval or metacestode stage of the dog tapeworm Echinococcus granulosus sensu lato (s.l.) [1]
Sequence analysis Protoscoleces processed for the investigations described showed 100% identity with the E. granulosus (s.s.) G1 genotype (NCBI GenBank sequence HM563011) [30]

Summary

Introduction

Cystic echinococcosis (CE) is a disease caused by the larval stage of Echinococcus granulosus sensu lato (s.l.). The treatment of CE mainly relies on the use of benzimidazoles, which can commonly cause adverse side effects. Human cystic echinococcosis (CE) is a global zoonosis caused by the larval or metacestode stage of the dog tapeworm Echinococcus granulosus sensu lato (s.l.) [1]. The benzimidazole (BMZ) compounds albendazole and mebendazole have been the cornerstone of drug-based CE treatment [1]. These are typically administered to inoperable patients with liver or lung CE and patients with multiple cysts in two or more organs, or peritoneal cysts [3]. New and more efficient treatment options are urgently needed [5]

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