title: Protection of human corneal epithelial cells from TNF-α-induced disruption of barrier function by rebamipide.
abstract: OBJECTIVE
  TNF-α disrupts the barrier function of cultured human corneal epithelial (HCE) cells. We investigated the effects of the cytoprotective drug rebamipide on this barrier disruption by TNF-α as well as on corneal epithelial damage in a rat model of dry eye.
  
  
  METHODS
  The barrier function of HCE cells was evaluated by measurement of transepithelial electrical resistance. The distribution of tight-junction (ZO-1, occludin) and adherens-junction (E-cadherin, β-catenin) proteins, and the p65 subunit of nuclear factor-κB (NF-κB) was determined by immunofluorescence microscopy. Expression of junctional proteins as well as phosphorylation of the NF-κB inhibitor IκB-α and myosin light chain (MLC) were examined by immunoblot analysis. A rat model of dry eye was developed by surgical removal of exorbital lacrimal glands.
  
  
  RESULTS
  Rebamipide inhibited the disruption of barrier function as well as the downregulation of ZO-1 expression, and the disappearance of ZO-1 from the interfaces of neighboring HCE cells induced by TNF-α. It also inhibited the phosphorylation and downregulation of IκB-α, the translocation of p65 to the nucleus, the formation of actin stress fibers, and the phosphorylation of MLC induced by TNF-α in HCE cells. Treatment with rebamipide eyedrops promoted the healing of corneal epithelial defects as well as attenuated the loss of ZO-1 from the surface of corneal epithelial cells in rats.
  
  
  CONCLUSIONS
  Rebamipide protects corneal epithelial cells from the TNF-α-induced disruption of barrier function by maintaining the distribution and expression of ZO-1 as well as the organization of the actin cytoskeleton. Rebamipide is, thus, a potential drug for preventing or ameliorating the loss of corneal epithelial barrier function associated with ocular inflammation.
authors.affiliation: Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan. k.kimura@yamaguchi-u.ac.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kimura
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Morita
authors.forename: Tomoko
authors.initials: T
authors.lastname: Orita
authors.forename: Junpei
authors.initials: J
authors.lastname: Haruta
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takeji
authors.forename: Koh-Hei
authors.initials: KH
authors.lastname: Sonoda
mesh_terms: D022005:Adherens Junctions / Q000187:drug effects; D000409:Alanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D015820:Cadherins / Q000378:metabolism; D002460:Cell Line; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D015352:Dry Eye Syndromes / Q000188:drug therapy / Q000378:metabolism; D017097:Electric Impedance; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D020672:I-kappa B Proteins; D015151:Immunoblotting; D008297:Male; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D062793:Occludin / Q000378:metabolism; D009883:Ophthalmic Solutions; D010766:Phosphorylation; D015363:Quinolones / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019108:Tight Junctions / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000633:toxicity*; D014945:Wound Healing / Q000187:drug effects; D062826:Zonula Occludens-1 Protein / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
chemical_list: D000975:Antioxidants; C495270:CTNNB1 protein, human; D015820:Cadherins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C000606206:Nfkbia protein, rat; C568985:OCLN protein, human; D062793:Occludin; D009883:Ophthalmic Solutions; D015363:Quinolones; C569042:TJP1 protein, human; D014409:Tumor Necrosis Factor-alpha; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin; D000072000:NF-KappaB Inhibitor alpha; C052785:rebamipide; D000409:Alanine