Analysis of small RNA secretion in cestode parasites

ANCAROLA M.E.; CUCHER M.

Seminario; Progress report; 2019

Echinococcosis is a worldwide zoonosis of public health concern caused by Echinococcus spp. These cestodes have an indirect life cycle in which the intermediate hosts (IH) become infected by ingesting eggs that develop into metacestodes (MC) mainly in the liver. The MC is a vesicle filled with hydatid fluid (HF) lined by an inner germinal layer that produces immature worms (protoscoleces-PS) and an outer acellular laminated layer. When the definitive host (DH) ingests PS, these develop into adults in the gut and release eggs in the host faeces. Echinococcus spp. show a long persistence in host tissues implying that parasites modulate the environment imposed by the host to allow their establishment, action that may involve extracellular vesicles (EV) transfer. In this work, we presented our contribution to the understanding of EV secretion in cestode parasites until the moment and share our preliminary results obtained during a research stay in the Institute of Hygiene and Microbiology, Würzburg, Germany.We analysed media conditioned by germinal layer primary cell cultures (PC), MC and PS, and also HF. Ultrastructural analyses showed the presence of EV-like structures in all the samples. Also, in MC tegument EV located in the interface between the laminated and germinal layers. Nanoparticle tracking analysis showed that EV concentration in MC was in the lower quantification limit, while in HF the concentration was ~20x higher. This suggests that MC EV may not be central in host-parasite interplay. Protein profiles assessed by LC-MS/MS showed a highly variable number of proteins identified, with only one protein detected in MC EV. Finally, hepatocytes were cultivated with labelled EV from PC and internalization was observed.In conclusion, EV may not be equally relevant in the host-parasite interplay throughout the life cycle of E. multilocularis since EV release depends on the morphology of the larval stages.