CONICET | Buscador de Institutos y Recursos Humanos

Humanechinococcosis is a zoonotic cestode disease caused by Echinococcus sp. larval stage (protoescoleces- PTS- and cysts or metacestode-MTC-).These helminth parasites lack digestive and excretory system but they havedeveloped active endocytic-exocytic cellular processes to regulate metabolite uptakeand excretion. In the present work, we analyzed the cestode extracellular vesicles(EVs) production and their interaction with host cells. Loperamide (Lp) acalcium channel blocker, reduced PTS and MTC viability in a dose-dependentmanner showing a significant effect with 10 μM and 25 μM after 24 h oftreatment, respectively. Additionaly, using the Fluo3-AM fluorescent probe, acytosolic calcium level increment (which was considered as an exocytosisstimulus) was determined in Lp-treated parasites in comparison to the controls.Moreover, the acetylcholinesterase activity in culture supernatants wasdetermined as an EVs-release indicator, revealing a higher activity in presenceof Lp. In addition, EVs were purified from parasite-culture medium through several centrifugation and ultracentrifugation steps and it was shownthat Lp-treatment provoked higher density of vesicles than the controlcondition. On the other hand, transmission electron microscopy enabled the vesiclesmorphological characterization and the identification of abundant exosomes.Finally, the EVs-host cell interaction was examined. Purified exosomes werelabeled with PKH26 red fluorescent labeling and the macrophages uptake andinteraction with hepatic cells were analyzed by confocal microscopy. Theseresults show that Echinococcus granulosuspossesses a great vesicular traffic which could be involved in the host immuneresponse.

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