title: The toxin biliatresone causes mouse extrahepatic cholangiocyte damage and fibrosis through decreased glutathione and SOX17.
abstract: Biliary atresia, the most common indication for pediatric liver transplantation, is a fibrotic disease of unknown etiology affecting the extrahepatic bile ducts of newborns. The recently described toxin biliatresone causes lumen obstruction in mouse cholangiocyte spheroids and represents a new model of biliary atresia. The goal of this study was to determine the cellular changes caused by biliatresone in mammalian cells that ultimately lead to biliary atresia and extrahepatic fibrosis. We treated mouse cholangiocytes in three-dimensional (3D) spheroid culture and neonatal extrahepatic duct explants with biliatresone and compounds that regulate glutathione (GSH). We examined the effects of biliatresone on SOX17 levels and determined the effects of Sox17 knockdown on cholangiocytes in 3D culture. We found that biliatresone caused disruption of cholangiocyte apical polarity and loss of monolayer integrity. Spheroids treated with biliatresone had increased permeability as shown by rhodamine efflux within 5 hours compared with untreated spheroids, which retained rhodamine for longer than 12 hours. Neonatal bile duct explants treated with the toxin showed lumen obstruction with increased subepithelial staining for α-smooth muscle actin and collagen, consistent with fibrosis. Biliatresone caused a rapid and transient decrease in GSH, which was both necessary and sufficient to mediate its effects in cholangiocyte spheroid and bile duct explant systems. It also caused a significant decrease in cholangiocyte levels of SOX17, and Sox17 knockdown in cholangiocyte spheroids mimicked the effects of biliatresone.
  
  
  
  Biliatresone decreases GSH and SOX17 in mouse cholangiocytes. In 3D cell systems, this leads to cholangiocyte monolayer damage and increased permeability; in extrahepatic bile duct explants, it leads to disruption of the extrahepatic biliary tree and subepithelial fibrosis. This mechanism may be important in understanding human biliary atresia. (Hepatology 2016;64:880-893).
authors.affiliation: Division of Gastroenterology, Hepatology and Nutrition, The Children's Hospital of Philadelphia, Philadelphia, PA.
authors.forename: Orith
authors.initials: O
authors.lastname: Waisbourd-Zinman
authors.affiliation: Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.|Department of Pediatrics, Yonsei University College of Medicine, Severance Children's Hospital, Seoul, South Korea.
authors.forename: Hong
authors.initials: H
authors.lastname: Koh
authors.affiliation: Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Shannon
authors.initials: S
authors.lastname: Tsai
authors.affiliation: Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Pierre-Marie
authors.initials: PM
authors.lastname: Lavrut
authors.affiliation: Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.|Department of Biological Sciences, University of the Sciences, Philadelphia, PA.
authors.forename: Christine
authors.initials: C
authors.lastname: Dang
authors.affiliation: Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Michael
authors.initials: M
authors.lastname: Pack
authors.affiliation: Department of Economic Development, Jobs, Transport and Resources, Government of Victoria, Victoria, Australia.
authors.forename: Jeff
authors.initials: J
authors.lastname: Cave
authors.affiliation: Department of Economic Development, Jobs, Transport and Resources, Government of Victoria, Victoria, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Hawes
authors.affiliation: Department of Biological Sciences, University of the Sciences, Philadelphia, PA.
authors.forename: Kyung A
authors.initials: KA
authors.lastname: Koo
authors.affiliation: Department of Biological Sciences, University of the Sciences, Philadelphia, PA.
authors.forename: John R
authors.initials: JR
authors.lastname: Porter
authors.affiliation: Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Rebecca G
authors.initials: RG
authors.lastname: Wells
mesh_terms: D000818:Animals; D052117:Benzodioxoles / Q000633:toxicity*; D017734:Bile Ducts, Extrahepatic / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D001656:Biliary Atresia / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005355:Fibrosis; D005978:Glutathione / Q000378:metabolism*; D024002:HMGB Proteins / Q000378:metabolism*; D008807:Mice, Inbred BALB C; D055760:SOXF Transcription Factors / Q000378:metabolism*
chemical_list: D052117:Benzodioxoles; D024002:HMGB Proteins; D055760:SOXF Transcription Factors; C511606:Sox17 protein, mouse; C000608133:biliatresone; D005978:Glutathione