Establishment and application of unbiasedin vitrodrug screening assays for the identification of compounds againstEchinococcus granulosus s.s

Abstract

AbstractEchinococcus multilocularisandE. granulosus s.l.are the causative agents of alveolar and cystic echinococcosis, respectively. Drug treatment options for these severe and neglected diseases are limited to benzimidazoles, which are not always efficacious, and adverse side effects are reported. Thus, novel and improved treatments are needed.In this study, the previously established platform forE. multilocularis in vitrodrug assessment was adapted toE. granulosus s.s.. In a first step,in vitroculture protocols forE. granulosus s.s.were established. This resulted in the generation of large amounts ofE. granulosus s.s.metacestode vesicles as well as germinal layer (GL) cells.In vitroculture of these cells formed metacestode vesicles displaying structural characteristics of metacestode vesicles generatedin vivo. Next, drug susceptibilities ofE. multilocularisandE. granulosus s.s.protoscoleces, metacestode vesicles and GL cells were comparatively assessed employing established assays including (i) metacestode vesicle damage marker release assay, (ii) metacestode vesicle viability assay, (iii) GL cell viability assay, and (iv) protoscolex motility assay. The standard drugs albendazole, buparvaquone, mefloquine, MMV665807, monepantel, niclosamide and nitazoxanide were included. MMV665807, niclosamide and nitazoxanide were active against the parasite in all four assays against both species. MMV665807 and monepantel were significantly more active againstE. multilocularismetacestode vesicles, while albendazole and nitazoxanide were significantly more active againstE. multilocularisGL cells. Albendazole displayed activity againstE. multilocularisGL cells, but no effects were seen in albendazole-treatedE. granulosus s.s.GL cells within five days. Treatment of protoscoleces with albendazole and monepantel had no impact on motility. Similar results were observed for both species with praziquantel and its enantiomers against protoscoleces. In conclusion,in vitroculture techniques and drug screening methods previously established forE. multiloculariswere successfully implemented forE. granulosus s.s.,allowing comparisons of drug efficacy between the two species.