title: Toll-like receptor 3 mediates PROMININ-1 expressing cell expansion in biliary atresia via Transforming Growth Factor-Beta.
abstract: BACKGROUND
  In biliary atresia (BA), epithelial-mesenchymal hepatic progenitor cells (HPC) expressing the stem/progenitor cell marker PROMININ-1 (PROM1) undergo expansion and subsequent transdifferentiation into collagen-producing myofibroblasts within regions of evolving biliary fibrosis under the regulation of Transforming Growth Factor-β (TGFβ) signaling. We hypothesized that pro-inflammatory Toll-like Receptor-3 (TLR3) signal activation promotes the differentiation of PROM1+ HPC via TGFβ pathway activation in vitro.
  
  
  METHODS
  PROM1+ Mat1a(-/-) HPC were treated with a double-stranded RNA analog, polyionosinic-polycytidylic acid (Poly I:C), ± small molecule inhibitors nafamostat, or SB431542.
  
  
  RESULTS
  Poly I:C induced myofibroblastic-like morphologic changes, degradation of IκB-α consistent with TLR3-NFκB activation, a 15-fold increase in the expression of Vimentin, a 9-fold increase in Collagen-1a, a 4.6-fold increase in Snail at 24h (p<0.05), and an 8.2-fold increase in Prom1 at 72h (p<0.0001) by qPCR. Immunofluorescence demonstrated nuclear phosphorylated SMAD3, TLR3, and COLLAGEN-1α staining following Poly I:C treatment. Degradation of IκBα was inhibited by nafamostat. Co-treatment with either nafamostat or SB431542 blocked the morphologic change and abrogated the increased expression of Cd133, Collagen, Vimentin, and Snail1.
  
  
  CONCLUSIONS
  TLR3 activation induces myofibroblastic differentiation of PROM1+ HPC in part via TGFβ pathway activation to promote BA-associated biliary fibrosis.
authors.affiliation: Developmental Biology, Regenerative Medicine and Stem Cell Program, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA; Division of Pediatric Surgery, Children's Hospital Los Angeles, Los Angeles, CA.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Zagory
authors.affiliation: Developmental Biology, Regenerative Medicine and Stem Cell Program, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA; Division of Pediatric Surgery, Children's Hospital Los Angeles, Los Angeles, CA.
authors.forename: Marie V
authors.initials: MV
authors.lastname: Nguyen
authors.affiliation: Developmental Biology, Regenerative Medicine and Stem Cell Program, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA.
authors.forename: William
authors.initials: W
authors.lastname: Dietz
authors.affiliation: Department of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA.
authors.forename: Nirmala
authors.initials: N
authors.lastname: Mavila
authors.affiliation: Developmental Biology, Regenerative Medicine and Stem Cell Program, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA.
authors.forename: Allison
authors.initials: A
authors.lastname: Haldeman
authors.affiliation: Developmental Biology, Regenerative Medicine and Stem Cell Program, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA; Division of Pediatric Surgery, Children's Hospital Los Angeles, Los Angeles, CA.
authors.forename: Anatoly
authors.initials: A
authors.lastname: Grishin
authors.affiliation: Developmental Biology, Regenerative Medicine and Stem Cell Program, The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA; Division of Pediatric Surgery, Children's Hospital Los Angeles, Los Angeles, CA. Electronic address: kwang@chla.usc.edu.
authors.forename: Kasper S
authors.initials: KS
authors.lastname: Wang
mesh_terms: D000071916:AC133 Antigen / Q000378:metabolism*; D001656:Biliary Atresia / Q000378:metabolism* / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation; D054338:Cell Transdifferentiation; D002478:Cells, Cultured; D005355:Fibrosis / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism / Q000473:pathology; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000378:metabolism* / Q000473:pathology; D058628:Myofibroblasts / Q000378:metabolism*; D015398:Signal Transduction; D051196:Toll-Like Receptor 3 / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: D000071916:AC133 Antigen; D015415:Biomarkers; C000606023:PROM1 protein, human; C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3; D016212:Transforming Growth Factor beta
keywords: Biliary atresia; CD133; Prominin-1; Toll-Like Receptor-3; Transforming Growth Factor-β; fibrosis