Parasite morphology affects extracellular vesicle secretion in cestodes.

ANCAROLA ME; MARCILLA A; LICHTENSTEIN G; MALDONADO L; HOLROYD, N; MARICONTI, M; BRUNETTI, E; BERRIMAN M; ALBRECHT K; ROSENZVIT M; KAMENETZKY L; BREHM K; CUCHER M

Congreso; 15th International Congress of Parasitology (ICOPA); 2022

Background and aims Currently, the secretion of extracellular vesicles (EV) is an undeniable mechanism of intercellular communication also functional in parasitic helminths, positioning EV as novel players in the host-pathogen interplay with promising biomarker potential. Here, we aimed to characterize EV secretion in three model species used to study tapeworm (cestode) biology: Mesocestoides corti and the taeniids Echinococcus multilocularis and Taenia crassiceps.MethodsMetacestodes were cultured in FBS-free medium. EV-enriched and EV-depleted fractions were collected by differential centrifugation. MET, NTA and LC-MS/MS were used to characterize EV. Capillary electrophoresis, small RNA-seq and RT-qPCR were used for small RNA profiling. Cestode EV proteomes were compared by orthology analysis. ResultsT. crassiceps and M. corti metacestodes secrete EV into the culture medium; however, the laminated layer of E. multilocularis hinders EV release. Accordingly, extracellular small RNAs from E. multilocularis are enriched in the EV-depleted fraction while the vesicular path prevails in the other two. The constraint imposed by the laminated layer diminishes when tegument integrity is compromised, with the consequent release of EV-associated RNA. Regarding EV proteins, comparative studies highlight the consistent detection of cestode-specific proteins with unknown function and EV marker potential useful for specific isolation/detection in complex samples, e.g. patient biofluids.ConclusionsIn vitro assays show that depending on each species morphology and parasite integrity status, metacestodes employ alternate paths to interact with the environment, which may affect the search of EV-based biomarkers.