title: Wnt3a induces exosome secretion from primary cultured rat microglia.
abstract: BACKGROUND
  Microglia, the immune effector cells of the CNS and the signaling molecule Wnt, both play critical roles in neurodevelopment and neurological disease. Here we describe the inducible release of exosomes from primary cultured rat microglia following treatment with recombinant carrier-free Wnt3a.
  
  
  RESULTS
  Wnt3a was internalised into microglia, being detectable in early endosomes, and secreted in exosomes through a GSK3-independent mechanism. Electron microscopy demonstrated that exosomes were elliptical, electron-dense (100 nm) vesicles that coalesced with time in vitro. In contrast to microglia, primary cortical neurons released exosomes constitutively and the quantity of exosomes released was not altered by Wnt3a treatment. The proteomic profile of the microglial-derived exosomes was characterised using liquid chromatography-tandem mass spectrometry (LC/MS/MS) and the vesicles were found to be associated with proteins involved in cellular architecture, metabolism, protein synthesis and protein degradation including β-actin, glyceraldehyde-3-phosphate dehydrogenase, ribosomal subunits and ubiquitin (45 proteins in total). Unlike lipopolysaccharide, Wnt3a did not induce a neurotoxic, pro-inflammatory phenotype in primary microglia.
  
  
  CONCLUSIONS
  These findings reveal a novel mechanism through which Wnt3a signals in microglia resulting in the release of exosomes loaded with proteinaceous cargo.
authors.affiliation: King's College London, MRC Centre for Neurodegenerative Research, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London SE5 8AF, UK. claudie.1.hooper@kcl.ac.uk
authors.forename: Claudie
authors.initials: C
authors.lastname: Hooper
authors.forename: Ricardo
authors.initials: R
authors.lastname: Sainz-Fuertes
authors.forename: Steven
authors.initials: S
authors.lastname: Lynham
authors.forename: Abdul
authors.initials: A
authors.lastname: Hye
authors.forename: Richard
authors.initials: R
authors.lastname: Killick
authors.forename: Alice
authors.initials: A
authors.lastname: Warley
authors.forename: Cecilia
authors.initials: C
authors.lastname: Bolondi
authors.forename: Jennifer
authors.initials: J
authors.lastname: Pocock
authors.forename: Simon
authors.initials: S
authors.lastname: Lovestone
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D055354:Exosomes / Q000378:metabolism* / Q000648:ultrastructure; D018836:Inflammation Mediators / Q000378:metabolism; D008297:Male; D017628:Microglia / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000502:physiology; D009474:Neurons / Q000378:metabolism; D061251:Primary Cell Culture / Q000379:methods*; D020543:Proteome / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D060509:Wnt3A Protein / Q000008:administration & dosage / Q000502:physiology*
chemical_list: D018836:Inflammation Mediators; D009419:Nerve Tissue Proteins; D020543:Proteome; D060509:Wnt3A Protein