Isolation and characterization of exosomes derived from fertile sheep hydatid cysts

•Hydatid cysts contain extracellular vesicles (EVs).•Exosomal signatures show that exosomes are represented in the isolated EVs.•Both parasite and host proteins are found in the EVs enriched fraction.•Several cyst structures potentially contribute to the exosomal cargo.

Cystic echinococcosis (CE) is a chronic and complex zoonotic disease. Information on the mechanisms involved in parasite establishment, growth and persistence remain limited. These may be modulated by a crosstalk between extracellular vesicles (EVs). EVs including exosomes and microvesicles are able to carry developmental signaling proteins which coordinate growth and establishment of several parasites. Here, an exosome enriched EV fraction was isolated from hydatid fluid (HF) of fertile sheep cysts. A proteomic analysis of this fraction identified a number of parasite-derived vesicle-membrane associated proteins as well as cytosolic proteins. Additionally, the exosomal enriched fraction contained proteins of host origin. Specific proteins −antigen B2 and TSPAN14- in the exosomal fraction were further assayed by immunoblot and transmission electron microscopy. To the best of our knowledge, this is the first report on the presence of parasite exosomes in fertile hydatid cyst fluid. Further characterization of the exosome cargo will allow the discovery of new markers for the detection of CE in humans and animals, and the treatment of CE patients, and provide new insights regarding the role of these EVs in the establishment and persistence of hydatid cysts.

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