title: Bile Salts at Low pH Cause Dilation of Intercellular Spaces in In Vitro Stratified Primary Esophageal Cells, Possibly by Modulating Wnt Signaling.
abstract: BACKGROUND
  The presence of dilated intercellular spaces in the stratified squamous lining of the esophagus is the pathognomonic feature of reflux esophagitis secondary to gastroesophageal reflux disease (GERD). In addition to stomach acid, bile salts are major constituents of gastroesophageal refluxate. The aim of our study was to determine the effect of bile salts cocktail at different pHs on epithelial junctions in an in vitro transwell model of stratified esophageal squamous epithelium.
  
  
  CONCLUSIONS
  Human telomerase reverse transcriptase (hTERT) immortalized primary esophageal EPC1 cells were grown on polyester transwell surfaces in calcium-enriched media. The cells exhibited gradual stratification into an 11-layered squamous epithelium over 7 days, together with epithelial barrier function as indicated by increased transepithelial electrical resistance (TEER). This stratified epithelium demonstrated well-formed tight junctions, adherens junctions, and desmosomes as visualized by immunofluorescence and electron microscopy. When exposed to short pulses of bile salts at pH 5, but not either condition alone, there was loss of stratification and decrease in TEER, concomitant with disruption of adherens junctions, tight junctions, and desmosomes, leading to the appearance of dilated intercellular spaces. At the cellular level, bile salts at pH 5 activated the Wnt pathway (indicated by increased β-catenin Ser552 phosphorylation).
  
  
  CONCLUSIONS
  In conclusion, in our in vitro transwell model bile salts at pH 5, but not bile salts or media at pH 5 alone, modulate Wnt signaling, disrupt different junctional complexes, and cause increased permeability of stratified squamous esophageal epithelium. These changes approximate the appearance of dilated intercellular space similar to that found in GERD patients.
authors.affiliation: Department of Surgery, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Sayak
authors.initials: S
authors.lastname: Ghatak
authors.affiliation: Department of Surgery, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Marie
authors.initials: M
authors.lastname: Reveiller
authors.affiliation: Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Liana
authors.initials: L
authors.lastname: Toia
authors.affiliation: Department of Human and Molecular Genetics, Virginia Commonwealth University Medical Center, Richmond, VA, USA.
authors.forename: Andrei I
authors.initials: AI
authors.lastname: Ivanov
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Zhongren
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Surgery, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Eileen M
authors.initials: EM
authors.lastname: Redmond
authors.affiliation: Department of Surgery, Boston University, Boston, MA, USA.
authors.forename: Tony E
authors.initials: TE
authors.lastname: Godfrey
authors.affiliation: University Hospitals Cleveland, Cleveland, OH, USA. Jeffrey.Peters@UHhospitals.org.
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Peters
mesh_terms: D001647:Bile Acids and Salts / Q000494:pharmacology*; D018929:Cell Culture Techniques; D017097:Electric Impedance; D004847:Epithelial Cells / Q000187:drug effects*; D004848:Epithelium / Q000187:drug effects / Q000473:pathology; D004947:Esophagus / Q000187:drug effects* / Q000473:pathology*; D005110:Extracellular Space / Q000187:drug effects*; D006801:Humans; D009092:Mucous Membrane / Q000187:drug effects / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects; D051176:beta Catenin / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D051176:beta Catenin
keywords: Bile salt; Dilated intercellular spaces; Gastroesophageal reflux disease