Regulated ion transport in mouse liver cyst epithelial cells

R. Brian Doctor, Sylene Johnson, Kelley S. Brodsky, Claudia R. Amura, Vincent Gattone, J. Gregory Fitz

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Derived from bile duct epithelia (BDE), secretion by liver cyst-lining epithelia is positioned to drive cyst expansion but the responsible ion flux pathways have not been characterized. Cyst-lining epithelia were isolated and cultured into high resistance monolayers to assess the ion secretory pathways. Electrophysiologic studies showed a marked rate of constitutive transepithelial ion transport, including Cl- secretion and Na+ absorption. Na+ absorption was amiloride-sensitive, suggesting the activation of epithelial sodium channels (ENaC). Further, both cAMPi and extracellular ATP induced robust secretory responses. Western blotting and immunohistologic analysis of liver cyst epithelia demonstrated expression of P2X4, a potent purinergic receptor in normal BDE. Luminometry and bioassaying measured physiologically relevant levels of ATP in a subset of liver cyst fluid samples. Liver cyst epithelia also displayed a significant capacity to degrade extracellular ATP. In conclusion, regulated ion transport pathways are present in liver cyst epithelia and are positioned to direct fluid secretion into the lumen of liver cysts and promote increases in liver cyst expansion and growth.

Original languageEnglish (US)
Pages (from-to)345-354
Number of pages10
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Volume1772
Issue number3
DOIs
StatePublished - Mar 1 2007

Keywords

  • Autosomal dominant polycystic kidney disease (ADPKD)
  • Epithelial sodium channel
  • Purinergic signaling
  • Ussing analysis
  • cAMP

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology

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