Occludin Content Modulates Hydrogen Peroxide-Induced Increase in Renal Epithelial Paracellular Permeability.
The ability of hydrogen peroxide (H2O2) to increase paracellular permeability of renal epithelial cell monolayers was examined and the role of occludin in this regulation was investigated. H2O2 treatment increased the paracellular movement of calcein, a marker for the leak pathway permeability, across monolayers of two renal epithelial cell lines, MDCK and LLC-PK1, in a concentration-dependent manner. At the same concentrations, H2O2 did not alter transepithelial resistance (TER) nor increase cell death. The magnitude of the H2O2-induced increase in leak pathway permeability was inversely related to cellular occludin protein content. H2O2 treatment did not produce any major change in total cellular content or Triton X-100-soluble or -insoluble fraction content of occludin protein. Occludin protein staining at the tight junction region was diminished following H2O2 treatment. The most dramatic effect of H2O2 was on the dynamic mobility of GFP-occludin into the tight junction region. H2O2 treatment slowed lateral movement of GFP-occludin into the tight junction region but not on the apical membrane. Further, removal of the cytoplasmic C-terminal region of occludin protein eliminated the effect of H2O2 on GFP-occludin lateral movement into the tight junction region. An increase in the mobile fraction of GFP-occludin was associated with a loss of response to H2O2. These data indicate that the H2O2-induced increase in renal epithelial cell paracellular permeability is mediated, at least in part, through occludin protein, possibly through a slowing of the rate of occludin movement into the tight junction region.
Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, 46202, Indiana.
Danielle
D
Janosevic
Department of Biomedical Sciences, NYIT College of Osteopathic Medicine, Old Westbury, 11568, New York.
Josephine
J
Axis
Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, 46202, Indiana.
Robert L
RL
Bacallao
Department of Biomedical Sciences, NYIT College of Osteopathic Medicine, Old Westbury, 11568, New York.
Kurt
K
Amsler
D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects*; D004285:Dogs; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000493:pharmacokinetics*; D007668:Kidney; D018374:LLC-PK1 Cells; D061985:Madin Darby Canine Kidney Cells; D062793:Occludin / Q000378:metabolism*; D013552:Swine; D019108:Tight Junctions / Q000378:metabolism
D062793:Occludin; D006861:Hydrogen Peroxide
FRAP; HYDROGEN PEROXIDE; OCCLUDIN; RENAL EPITHELIAL CELL; TIGHT JUNCTION