title: Exosomes mediate intercellular transfer of pro-fibrogenic connective tissue growth factor (CCN2) between hepatic stellate cells, the principal fibrotic cells in the liver.
abstract: BACKGROUND
  Fibrogenic pathways in the liver are principally regulated by hepatic stellate cells (HSC), which produce and respond to fibrotic mediators such as connective tissue growth factor (CCN2). The aim of this study was to determine whether CCN2 is shuttled between HSC in membranous nanovesicles, or "exosomes."
  
  
  METHODS
  Exosomes were incubated with HSC after isolation from conditioned medium of control or CCN2-green fluorescent protein (GFP)-transfected primary mouse HSC or human LX-2 HSC. Some exosomes were stained fluorescently with PKH26. HSC co-culture experiments were performed in the presence of GW4869 exosome inhibitor. CCN2 or CCN2-GFP were evaluated by quantitative real-time polymerase chain reaction or Western blot.
  
  
  RESULTS
  HSC-derived exosomes contained CCN2 or CCN2 mRNA, each of which increased in concentration during HSC activation or after transfection of HSC with CCN2-GFP. Exosomes, stained with either PKH26 or purified from CCN2-GFP-transfected cells, were taken up by activated or quiescent HSC resulting in CCN2-GFP delivery, as shown by their direct addition to recipient cells or by the GW4869-dependency of donor HSC.
  
  
  CONCLUSIONS
  CCN2 is packaged into secreted, nano-sized exosomes that mediate its intercellular transfer between HSC. Exosomal CCN2 may amplify or fine tune fibrogenic signaling and, in conjunction with other exosome constituents, may have utility as a noninvasive biomarker to assess hepatic fibrosis.
authors.affiliation: Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Charrier
authors.affiliation: Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH.
authors.forename: Ruju
authors.initials: R
authors.lastname: Chen
authors.affiliation: Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.affiliation: Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH.
authors.forename: Sherri
authors.initials: S
authors.lastname: Kemper
authors.affiliation: Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Hattori
authors.affiliation: Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Takigawa
authors.affiliation: Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH; Department of Pediatric Surgery, Nationwide Children's Hospital, Columbus, OH; Department of Surgery, The Ohio State University, Columbus, OH. Electronic address: David.Brigstock@NationwideChildrens.Org.
authors.forename: David R
authors.initials: DR
authors.lastname: Brigstock
mesh_terms: D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D001597:Benzylidene Compounds / Q000494:pharmacology; D001693:Biological Transport, Active / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D018920:Coculture Techniques; D055513:Connective Tissue Growth Factor / Q000235:genetics / Q000378:metabolism*; D055354:Exosomes / Q000187:drug effects / Q000378:metabolism*; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection
chemical_list: D000814:Aniline Compounds; D001597:Benzylidene Compounds; C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; C468773:GW 4869; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D055513:Connective Tissue Growth Factor