Reference - Detail
|Author||Kimura K, Teranishi S, Fukuda K, Kawamoto K, Nishida T.|
|Title||Delayed disruption of barrier function in cultured human corneal epithelial cells induced by tumor necrosis factor-alpha in a manner dependent on NF-kappaB.|
|Journal||Invest Ophthalmol Vis Sci|
PURPOSE:The corneal epithelium provides a barrier that is both important for corneal homeostasis and dependent on tight junctions (TJs) between adjacent epithelial cells. The authors examined the effects of tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, on barrier function and the expression of TJ proteins in simian virus 40-transformed human corneal epithelial (HCE) cells.
METHODS:The barrier function of cultured HCE cells was evaluated by measurement of transepithelial electrical resistance (TER). The subcellular distribution of the TJ proteins zonula occludens-1 (ZO-1) and occludin and that of the p65 subunit of nuclear factor-kappaB (NF-kappaB) were determined by immunofluorescence staining. The expression of ZO-1 and occludin and the phosphorylation and degradation of the NF-kappaB inhibitory protein IkappaB-alpha were examined by immunoblot analysis.
RESULTS:TNF-alpha induced a decrease in the TER of HCE cells in a concentration- and time-dependent manner. It also induced the disappearance of ZO-1 from the interfaces of neighboring HCE cells without affecting the localization of occludin. The abundance of neither ZO-1 nor occludin was affected by TNF-alpha. TNF-alpha induced the phosphorylation and downregulation of IkappaB-alpha and the translocation of the p65 subunit of NF-kappaB to the nucleus. The NF-kappaB inhibitor curcumin blocked the effects of TNF-alpha on TER and the subcellular localization of ZO-1 at late phase.
CONCLUSIONS:TNF-alpha disrupted the barrier function of HCE cells, apparently by affecting the localization of ZO-1 at TJs in a manner dependent on NF-kappaB at late phase. This action of TNF-alpha may contribute to the loss of corneal epithelial barrier function associated with ocular inflammation.
|MeSH||Cell Membrane Permeability / drug effects Cells, Cultured Curcumin / pharmacology Dose-Response Relationship, Drug Down-Regulation Electric Impedance Epithelium, Corneal / cytology Epithelium, Corneal / drug effects* Epithelium, Corneal / metabolism Fluorescent Antibody Technique, Indirect Humans I-kappa B Proteins / metabolism Immunoblotting Membrane Proteins / metabolism NF-KappaB Inhibitor alpha Occludin Phosphoproteins / metabolism Phosphorylation Tight Junctions / drug effects* Tight Junctions / metabolism Time Factors Transcription Factor RelA / antagonists & inhibitors Transcription Factor RelA / metabolism* Tumor Necrosis Factor-alpha / pharmacology* Zonula Occludens-1 Protein|
|Human and Animal Cells||HCE-T(RCB2280)|