Exosome secretion affects social motility in Trypanosoma brucei

PLoS Pathog. 2017 Mar 3;13(3):e1006245. doi: 10.1371/journal.ppat.1006245. eCollection 2017 Mar.

Abstract

Extracellular vesicles (EV) secreted by pathogens function in a variety of biological processes. Here, we demonstrate that in the protozoan parasite Trypanosoma brucei, exosome secretion is induced by stress that affects trans-splicing. Following perturbations in biogenesis of spliced leader RNA, which donates its spliced leader (SL) exon to all mRNAs, or after heat-shock, the SL RNA is exported to the cytoplasm and forms distinct granules, which are then secreted by exosomes. The exosomes are formed in multivesicular bodies (MVB) utilizing the endosomal sorting complexes required for transport (ESCRT), through a mechanism similar to microRNA secretion in mammalian cells. Silencing of the ESCRT factor, Vps36, compromised exosome secretion but not the secretion of vesicles derived from nanotubes. The exosomes enter recipient trypanosome cells. Time-lapse microscopy demonstrated that cells secreting exosomes or purified intact exosomes affect social motility (SoMo). This study demonstrates that exosomes are delivered to trypanosome cells and can change their migration. Exosomes are used to transmit stress signals for communication between parasites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Northern
  • Cell Line
  • Exosomes / metabolism*
  • Image Processing, Computer-Assisted
  • In Situ Hybridization, Fluorescence
  • Microscopy, Electron
  • Time-Lapse Imaging
  • Trypanosoma brucei brucei / metabolism*

Grants and funding

This study was supported by a grant from the Israel-US Binational Science Foundation (BSF), and by the Israel Science Foundation, and I-core grants 41/11 and 1796/12. SM holds the David and Inez Myers Chair in RNA silencing of diseases. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.