title: Myosin light chain kinase inhibition: correction of increased intestinal epithelial permeability in vitro.
abstract: OBJECTIVE
  To examine whether myosin light chain kinase (MLCK) inhibitors can reduce intestinal epithelial permeability increases in vitro.
  
  
  METHODS
  Isolated rat, mouse and human colonic tissue mucosae and Caco-2 monolayers were exposed to cytochalasin D (cD) and sodium caprate (C10), in the absence and presence of the MLCK inhibitors, ML-9 and D PIK. Transepithelial electrical resistance (TEER) and Papp of [14C]-mannitol or FITC-dextran 4000 (FD-4) were measured. Western blots were used to measure MLC phosphorylation.
  
  
  RESULTS
  Increases in Papp of [14C]-mannitol and decreases in TEER were induced by tight junction openers. These changes were attenuated by ML-9. D-PIK offset the FD-4 Papp increase induced by C10 in Caco-2 only, while ML-9 and PIK inhibited MLC directly, cD induced constriction of peri-junctional actin in Caco-2 monolayers, but this was prevented by ML-9. Although mannitol fluxes across colonic mucosae from dextran-sulphate (DSS)-treated mice were higher than control, they were not ameliorated by either ML-9 or PIK in vitro.
  
  
  CONCLUSIONS
  ML-9 inhibits paracellular permeability increases in several intestinal epithelial models. D-PIK reduced stimulated paracellular fluxes in Caco-2 monolayers, but not in tissue. Pre-established increases were not modified by two MLCK inhibitors in a mouse model of IBD.
authors.affiliation: School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Linda M
authors.initials: LM
authors.lastname: Feighery
authors.forename: Sean W
authors.initials: SW
authors.lastname: Cochrane
authors.forename: Teresa
authors.initials: T
authors.lastname: Quinn
authors.forename: Alan W
authors.initials: AW
authors.lastname: Baird
authors.forename: Daniel
authors.initials: D
authors.lastname: O'Toole
authors.forename: Sian-Eleri
authors.initials: SE
authors.lastname: Owens
authors.forename: Diarmuid
authors.initials: D
authors.lastname: O'Donoghue
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Mrsny
authors.forename: David J
authors.initials: DJ
authors.lastname: Brayden
mesh_terms: D000818:Animals; D015153:Blotting, Western; D017097:Electric Impedance; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008353:Mannitol / Q000493:pharmacokinetics; D051379:Mice; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors*; D010539:Permeability; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D047428:Protein Kinase Inhibitors; D008353:Mannitol; D009219:Myosin-Light-Chain Kinase