title: Bile acids increase alveolar epithelial permeability via mitogen-activated protein kinase, cytosolic phospholipase A2 , cyclooxygenase-2, prostaglandin E2 and junctional proteins.
abstract: OBJECTIVE
  Bile acid (BA) aspiration is associated with various lung diseases. It was hypothesized that BA may induce changes in alveolar epithelium permeability and contribute to the pathogenesis of lung injury.
  
  
  METHODS
  Human alveolar epithelial cells were grown in monolayer and stimulated with a major component of BA, chenodeoxycholic acid (CDCA). Transepithelial electrical resistance (TER) and paracellular fluxes were measured to assess permeability alteration. Prostaglandin E2 ( PGE2 ) production was measured, and its effect on TER and junctional proteins (JP) was also examined. Reverse transcription polymerase chain reaction and Western blots were used to investigate the expression of messenger RNA and JP.
  
  
  RESULTS
  CDCA induced significant p38 and c-Jun N-terminal kinase (JNK) phosphorylation, cytosolic phospholipase A2 (cPLA2 ) and cyclooxygenase-2 (COX-2) messenger RNA expression, PGE2 production, TER reduction and decay of JP (including occludin, zonula occludens-1 (ZO-1) and E-cadherin, in which ZO-1 had maximal change). CDCA also increased paracellular fluxes, which was abolished by dexamethasone. Both CDCA and PGE2 contributed to TER reduction in an identical trend and a dose-response manner. PGE2 also reduced ZO-1 expression, which was similar to that observed by CDCA stimulation. Pretreatment with inhibitors of p38 (SB203580), JNK (SP600125), cPLA2 (mepacrine) and COX-2 (NS398) as well as dexamethasone reversed the CDCA-induced PGE2 production, TER reduction and decay of ZO-1.
  
  
  CONCLUSIONS
  The increase in alveolar permeability was associated with decay of JP. BA may induce permeability alteration through the upregulation of mitogen-activated protein kinase, cPLA2 , COX-2, PGE2 and JP, which may contribute to the pathogenesis of BA-associated lung injury.
authors.affiliation: Institute of Emergency and Critical Care Medicine, School of Medicine, Taipei, Taiwan.
authors.forename: Kang-Cheng
authors.initials: KC
authors.lastname: Su
authors.forename: Yu-Chung
authors.initials: YC
authors.lastname: Wu
authors.forename: Chun-Sheng
authors.initials: CS
authors.lastname: Chen
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Hung
authors.forename: Yi-Han
authors.initials: YH
authors.lastname: Hsiao
authors.forename: Ching-Min
authors.initials: CM
authors.lastname: Tseng
authors.forename: Shi-Chuan
authors.initials: SC
authors.lastname: Chang
authors.forename: Yu-Chin
authors.initials: YC
authors.lastname: Lee
authors.forename: Diahn-Warng
authors.initials: DW
authors.lastname: Perng
mesh_terms: D001647:Bile Acids and Salts / Q000494:pharmacology*; D015820:Cadherins / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D002635:Chenodeoxycholic Acid / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D062793:Occludin / Q000378:metabolism; D054510:Phospholipases A2, Cytosolic / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D062725:Tight Junction Proteins / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D015820:Cadherins; D062793:Occludin; C569042:TJP1 protein, human; D062725:Tight Junction Proteins; D062826:Zonula Occludens-1 Protein; D002635:Chenodeoxycholic Acid; D051546:Cyclooxygenase 2; D020929:Mitogen-Activated Protein Kinase Kinases; D054510:Phospholipases A2, Cytosolic; D015232:Dinoprostone