title: Protein and small non-coding RNA-enriched extracellular vesicles are released by the pathogenic blood fluke Schistosoma mansoni.
abstract: BACKGROUND
  Penetration of skin, migration through tissues and establishment of long-lived intravascular partners require Schistosoma parasites to successfully manipulate definitive host defences. While previous studies of larval schistosomula have postulated a function for excreted/secreted (E/S) products in initiating these host-modulatory events, the role of extracellular vesicles (EVs) has yet to be considered. Here, using preparatory ultracentrifugation as well as methodologies to globally analyse both proteins and small non-coding RNAs (sncRNAs), we conducted the first characterization of Schistosoma mansoni schistosomula EVs and their potential host-regulatory cargos.
  
  
  RESULTS
  Transmission electron microscopy analysis of EVs isolated from schistosomula in vitro cultures revealed the presence of numerous, 30-100 nm sized exosome-like vesicles. Proteomic analysis of these vesicles revealed a core set of 109 proteins, including homologs to those previously found enriched in other eukaryotic EVs, as well as hypothetical proteins of high abundance and currently unknown function. Characterization of E/S sncRNAs found within and outside of schistosomula EVs additionally identified the presence of potential gene-regulatory miRNAs (35 known and 170 potentially novel miRNAs) and tRNA-derived small RNAs (tsRNAs; nineteen 5' tsRNAs and fourteen 3' tsRNAs).
  
  
  CONCLUSIONS
  The identification of S. mansoni EVs and the combinatorial protein/sncRNA characterization of their cargo signifies that an important new participant in the complex biology underpinning schistosome/host interactions has now been discovered. Further work defining the role of these schistosomula EVs and the function/stability of intra- and extra-vesicular sncRNA components presents tremendous opportunities for developing novel schistosomiasis diagnostics or interventions.
authors.affiliation: IBERS, Aberystwyth University, Aberystwyth, UK.
authors.forename: Fanny C
authors.initials: FC
authors.lastname: Nowacki
authors.affiliation: IBERS, Aberystwyth University, Aberystwyth, UK.
authors.forename: Martin T
authors.initials: MT
authors.lastname: Swain
authors.affiliation: Centre for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Oleg I
authors.initials: OI
authors.lastname: Klychnikov
authors.affiliation: IBERS, Aberystwyth University, Aberystwyth, UK.
authors.forename: Umar
authors.initials: U
authors.lastname: Niazi
authors.affiliation: Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Alasdair
authors.initials: A
authors.lastname: Ivens
authors.affiliation: Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Quintana
authors.affiliation: Centre for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Hensbergen
authors.affiliation: Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Cornelis H
authors.initials: CH
authors.lastname: Hokke
authors.affiliation: Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Amy H
authors.initials: AH
authors.lastname: Buck
authors.affiliation: IBERS, Aberystwyth University, Aberystwyth, UK; krh@aber.ac.uk.
authors.forename: Karl F
authors.initials: KF
authors.lastname: Hoffmann
keywords: Schistosoma mansoni; extracellular vesicles; miRNAs; platyhelminth; proteome; small non-coding RNAs; tsRNAs