title: Autophagy Deficiency Diminishes Indomethacin-Induced Intestinal Epithelial Cell Damage through Activation of the ERK/Nrf2/HO-1 Pathway.
abstract: Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause epithelial cell damage in the stomach, intestine, and colon. NSAIDs are reported to induce autophagy and apoptosis in intestinal epithelial cells; however, their role in cell damage is poorly understood. To examine the role of autophagy in cell damage, we used autophagy-related gene Atg5-conditional knockout mice, in which the Atg5 gene is only knocked out in intestinal epithelial cells. In an indomethacin (IM)-induced gastrointestinal ulcer mouse model, intestinal epithelium damage was reduced in Atg5-conditional knockout mice compared with wild-type mice. IM-induced damage in IEC6 rat intestinal epithelial cells was reduced when Atg5 was silenced (IEC6shAtg5 cells). Western blot analyses indicated that IM-induced apoptosis decreased, and the potent, oxidative stress-related extracellular signal-regulated kinase (ERK)/nuclear factor-erythroid2-like2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway was upregulated in IEC6shAtg5 cells. An experiment using a reactive oxygen species (ROS)-sensitive fluorescent dye in IEC6shAtg5 cells revealed that the amount of ROS at the baseline and the rate of increase after IM treatment were lower than in intact IEC6 cells. The mitochondrial membrane potential at the baseline and the reduction rate in IM-treated IEC6shAtg5 cells were lower than in intact IEC6 cells, indicating that autophagy deficiency increased ROS production caused by mitochondrial disturbance. Furthermore, MnTMPyP, a manganese-superoxide dismutase mimetic, significantly inhibited IM-induced autophagy and subsequent apoptosis as well as activation of the ERK/Nrf2/HO-1 pathway. These data suggest that autophagy deficiency and subsequent activation of the ERK/Nrf2/HO-1 pathway diminished IM-induced, apoptosis-mediated intestinal epithelial cell damage, and genetic analyses of single nucleotide polymorphisms in autophagy-related genes could predict NSAID-induced intestinal injury.
authors.affiliation: Departments of Internal Medicine II (S.H., S.E., T.T., T.I., K.H.) and Pharmacology (T.N., S.Y., M.A.), Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Harada
authors.affiliation: Departments of Internal Medicine II (S.H., S.E., T.T., T.I., K.H.) and Pharmacology (T.N., S.Y., M.A.), Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: Departments of Internal Medicine II (S.H., S.E., T.T., T.I., K.H.) and Pharmacology (T.N., S.Y., M.A.), Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Yokoe
authors.affiliation: Departments of Internal Medicine II (S.H., S.E., T.T., T.I., K.H.) and Pharmacology (T.N., S.Y., M.A.), Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Edogawa
authors.affiliation: Departments of Internal Medicine II (S.H., S.E., T.T., T.I., K.H.) and Pharmacology (T.N., S.Y., M.A.), Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka, Japan.
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Takeuchi
authors.affiliation: Departments of Internal Medicine II (S.H., S.E., T.T., T.I., K.H.) and Pharmacology (T.N., S.Y., M.A.), Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Departments of Internal Medicine II (S.H., S.E., T.T., T.I., K.H.) and Pharmacology (T.N., S.Y., M.A.), Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka, Japan.
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Higuchi
authors.affiliation: Departments of Internal Medicine II (S.H., S.E., T.T., T.I., K.H.) and Pharmacology (T.N., S.Y., M.A.), Faculty of Medicine, Osaka Medical College, Takatsuki, Osaka, Japan masahi@osaka-med.ac.jp.
authors.forename: Michio
authors.initials: M
authors.lastname: Asahi
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000633:toxicity*; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D000071187:Autophagy-Related Protein 5; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D004847:Epithelial Cells / Q000187:drug effects*; D016166:Free Radical Scavengers / Q000494:pharmacology; D020868:Gene Silencing; D051547:Heme Oxygenase-1 / Q000187:drug effects*; D007213:Indomethacin / Q000633:toxicity*; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D018345:Mice, Knockout; D008869:Microtubule-Associated Proteins / Q000235:genetics; D051267:NF-E2-Related Factor 2 / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D011506:Proteins / Q000187:drug effects / Q000235:genetics; D051381:Rats
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C495773:Atg5 protein, mouse; C545865:Atg5 protein, rat; D000071187:Autophagy-Related Protein 5; D016166:Free Radical Scavengers; D008869:Microtubule-Associated Proteins; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D011506:Proteins; D051547:Heme Oxygenase-1; D007213:Indomethacin