PURPOSE: To examine whether myosin light chain kinase (MLCK) inhibitors can reduce intestinal epithelial permeability increases in vitro. MATERIALS AND 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.
PURPOSE: To examine whether myosin light chain kinase (MLCK) inhibitors can reduce intestinal epithelial permeability increases in vitro. MATERIALS AND 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: Donnie E Shifflett; Daniel R Clayburgh; Athanasia Koutsouris; Jerrold R Turner; Gail A Hecht Journal: Lab Invest Date: 2005-10 Impact factor: 5.662
Authors: Burhan Hameed; David M Smith; Jon J Verrechio; J David Schmidt; Leesa E Gillooley; Mary Carmen Valenzano; Simon A Lewis; James M Mullin Journal: Dig Dis Sci Date: 2004-09 Impact factor: 3.199
Authors: Ashish R Kurundkar; Cheryl R Killingsworth; R Britt McIlwain; Joseph G Timpa; Yolanda E Hartman; Dongning He; Rajendra K Karnatak; Mary L Neel; John P Clancy; G M Anantharamaiah; Akhil Maheshwari Journal: Pediatr Res Date: 2010-08 Impact factor: 3.756