title: Checkpoint Kinase 1 Activation Enhances Intestinal Epithelial Barrier Function via Regulation of Claudin-5 Expression.
abstract: Several stressors are known to influence epithelial tight junction (TJ) integrity, but the association between DNA damage and TJ integrity remains unclear. Here we examined the effects of daunorubicin and rebeccamycin, two anti-tumor chemicals that induce DNA damage, on TJ integrity in human intestinal epithelial cells. Daunorubicin and rebeccamycin dose-dependently enhanced transepithelial electrical resistance (TER) and decreased flux of the 4 kDa FITC-dextran in Caco-2 cell monolayer. Daunorubicin- or rebeccamycin-induced enhancement of the TJ barrier function partly rescued attenuation of the barrier function by the inflammatory cytokines TNF-α and IFN-γ. Daunorubicin and rebeccamycin increased claudin-5 expression and the product was distributed in the actin cytoskeleton fraction, which was enriched with TJ proteins. Caffeine, which is an inhibitor of ataxia telangiectasia mutated protein (ATM) and ataxia telangiectasia mutated and Rad3-related protein (ATR), and the Chk1 inhibitor inhibited the TER increases induced by daunorubicin and rebeccamycin, whereas a Chk2 inhibitor did not. Treatment with Chk1 siRNA also significantly inhibited the TER increases. Induction of claudin-5 expression was inhibited by Chk1 inhibitor and by siRNA treatment. Our results suggest that Chk1 activation by daunorubicin and rebeccamycin induced claudin-5 expression and enhanced TJ barrier function in Caco-2 cell monolayer, which suggests a link between DNA damage and TJ integrity in the human intestine.
authors.affiliation: Laboratories of Bio-Functional Molecular Chemistry, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Watari
authors.affiliation: Laboratories of Bio-Functional Molecular Chemistry, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Hasegawa
authors.affiliation: Laboratories of Bio-Functional Molecular Chemistry, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan.
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Yagi
authors.affiliation: Laboratories of Bio-Functional Molecular Chemistry, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan.
authors.forename: Masuo
authors.initials: M
authors.lastname: Kondoh
mesh_terms: D018938:Caco-2 Cells; D002227:Carbazoles / Q000494:pharmacology; D000071877:Checkpoint Kinase 1; D062507:Claudin-5 / Q000235:genetics*; D003630:Daunorubicin / Q000494:pharmacology; D004789:Enzyme Activation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D007413:Intestinal Mucosa / Q000502:physiology*; D011494:Protein Kinases / Q000378:metabolism*
chemical_list: C107466:CLDN5 protein, human; D002227:Carbazoles; D062507:Claudin-5; C053339:rebeccamycin; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D003630:Daunorubicin