title: Statin pretreatment inhibits the lipopolysaccharide-induced epithelial-mesenchymal transition via the downregulation of toll-like receptor 4 and nuclear factor-κB in human biliary epithelial cells.
abstract: OBJECTIVE
  Epithelial-mesenchymal transition (EMT) of biliary epithelial cells (BECs) plays an important role in biliary fibrosis. This study investigated the effects of simvastatin on the lipopolysaccharide (LPS)-induced EMT and related signal pathways in BECs.
  
  
  METHODS
  Biliary epithelial cells were exposed to LPS (2 µg/mL) or transforming growth factor β1 (TGF-β1) (5 ng/mL) for 5 days. The EMT was assessed by a gain of mesenchymal cell markers (vimentin, N-cadherin, slug, and Twist-1) and a loss of epithelial cell markers (E-cadherin). The effects of simvastatin on the EMT induced by LPS or TGF-β1 were determined by the changes in the levels of EMT markers and TLR4 and in the c-Jun N-terminal kinase (JNK), p38, and nuclear factor-κB (NF-κB) signaling pathways.
  
  
  RESULTS
  Compared with the BECs treated with LPS alone, co-treatment with simvastatin and LPS induced an increase in the expression of E-cadherin and decreases in the expression levels of mesenchymal cell markers. The LPS-induced TLR4 expression level was slightly decreased by co-treatment with simvastatin. LPS-induced BEC growth was markedly inhibited by co-treatment with simvastatin. Furthermore, pretreatment with simvastatin inhibited the LPS-induced EMT in BECs by downregulating NF-κB and JNK phosphorylation. The suppressive effects of simvastatin pretreatment on the induction of the EMT by TGF-β1 were also demonstrated in H69 cells.
  
  
  CONCLUSIONS
  Our results demonstrate that LPS or TGF-β1 promote the EMT in BECs that that pretreatment with simvastatin inhibited the induced EMT by downregulating toll-like receptor 4 and NF-κB phosphorylation. This finding suggests that simvastatin can be considered a new agent for preventing biliary fibrosis associated with the EMT of BECs.
authors.affiliation: Departments of Physiology, Chungbuk National University College of Medicine, Chungbuk, Korea.
authors.forename: Yangmi
authors.identifier: http://orcid.org/0000-0003-1536-116X
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Chungbuk National University College of Medicine, Chungbuk, Korea.
authors.forename: Eun Jeoung
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Departments of Physiology, Chungbuk National University College of Medicine, Chungbuk, Korea.
authors.forename: Hee Kyung
authors.initials: HK
authors.lastname: Jang
authors.affiliation: Department of Pharmacology, Chungbuk National University College of Medicine, Chungbuk, Korea.
authors.forename: Chan Hyung
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, College of Medicine, Chonbuk National University, Jeonju, Korea.
authors.forename: Dae-Ghon
authors.initials: DG
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Chungbuk National University College of Medicine, Chungbuk, Korea.
authors.forename: Joung-Ho
authors.initials: JH
authors.lastname: Han
authors.affiliation: Department of Internal Medicine, Chungbuk National University College of Medicine, Chungbuk, Korea.
authors.forename: Seon Mee
authors.initials: SM
authors.lastname: Park
mesh_terms: D001652:Bile Ducts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D002461:Cell Line, Transformed; D049109:Cell Proliferation / Q000187:drug effects; D019610:Cytoprotection; D015536:Down-Regulation; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008070:Lipopolysaccharides / Q000633:toxicity*; D008105:Liver Cirrhosis, Biliary / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation; D015398:Signal Transduction / Q000187:drug effects; D019821:Simvastatin / Q000494:pharmacology*; D013997:Time Factors; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000633:toxicity
chemical_list: D015415:Biomarkers; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D008070:Lipopolysaccharides; D016328:NF-kappa B; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D053773:Transforming Growth Factor beta1; D019821:Simvastatin; D048031:JNK Mitogen-Activated Protein Kinases
keywords: TGF-β1; biliary epithelial cells; epithelial-mesenchymal transition; lipopolysaccharide; simvastatin; toll-like receptor 4