Extracellular vesicles from parasitic helminths contain specific excretory/secretory proteins and are internalized in intestinal host cells

PLoS One. 2012;7(9):e45974. doi: 10.1371/journal.pone.0045974. Epub 2012 Sep 24.

Abstract

The study of host-parasite interactions has increased considerably in the last decades, with many studies focusing on the identification of parasite molecules (i.e. surface or excretory/secretory proteins (ESP)) as potential targets for new specific treatments and/or diagnostic tools. In parallel, in the last few years there have been significant advances in the field of extracellular vesicles research. Among these vesicles, exosomes of endocytic origin, with a characteristic size ranging from 30-100 nm, carry several atypical secreted proteins in different organisms, including parasitic protozoa. Here, we present experimental evidence for the existence of exosome-like vesicles in parasitic helminths, specifically the trematodes Echinostoma caproni and Fasciola hepatica. These microvesicles are actively released by the parasites and are taken up by host cells. Trematode extracellular vesicles contain most of the proteins previously identified as components of ESP, as confirmed by proteomic, immunogold labeling and electron microscopy studies. In addition to parasitic proteins, we also identify host proteins in these structures. The existence of extracellular vesicles explains the secretion of atypical proteins in trematodes, and the demonstration of their uptake by host cells suggests an important role for these structures in host-parasite communication, as described for other infectious agents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Echinostoma / physiology*
  • Echinostoma / ultrastructure
  • Echinostomiasis / metabolism
  • Echinostomiasis / parasitology
  • Exosomes / metabolism*
  • Fasciola hepatica / physiology*
  • Fasciola hepatica / ultrastructure
  • Fascioliasis / metabolism
  • Fascioliasis / parasitology
  • Helminth Proteins / metabolism*
  • Host-Parasite Interactions*
  • Humans
  • Intestinal Mucosa / cytology
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / parasitology*
  • Rats

Substances

  • Helminth Proteins

Grants and funding

Funding was provided by FIS09/02355 and SAF2010-16236 from the Spanish Ministry of Science and Innovation and FEDER; PROMETEO/2009/081 from Conselleria d'Educació, Generalitat Valenciana (Valencia, Spain), and UV-AE-10- 23739 from the Universitat de València (Valencia, Spain). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.