Authors

A Bennett¹; E de la Torre-Escudero¹; M W Robinson¹;  ¹ Queen's University Belfast

Discussion

Extracellular vesicles (EVs) released by helminths are now recognised as major players at the host-parasite interface. However, there is a limited understanding of the molecular machinery controlling their production. Here, we address this using a comparative genomics approach. From an extensive search of the literature, corroborated with helminth EV proteomic data, we identified 104 putative EV biogenesis proteins and used these to interrogate a variety of helminth genomes. We have found that whilst subunits of the Endosomal Complex Required for Transport (ESCRT) pathway are broadly conserved across most helminths, sequence analysis reveals significant differences in the domains required for interactions between pathway members. As part of our genomic analysis we have identified a trematode-specific EV marker (tetraspanin) that is localised to a vesicle population associated with the gastrodermal cells of Fasciola hepatica. Further localisation studies demonstrate differing spatial expression patterns of two classic exosomal markers involved in the ESCRT pathway, supporting the notion that a non-canonical ESCRT pathway could exist in helminths. From this work, we infer that ESCRT-dependent pathways have the potential to operate in helminths, including species in which the release of EVs has yet to be described, and reveal putative sites of EV biogenesis in F. hepatica. In doing so, we provide a platform to investigate EV production in helminths using functional studies.