title: Epimorphin protects hepatocytes from oxidative stress by inhibiting mitochondrial injury.
abstract: OBJECTIVE
  Many investigations have demonstrated that cell injuries caused by generation of reactive oxygen species (ROS) is a common mechanism of various hepatic disorders. Recently, we have demonstrated that epimorphin, originally cloned as a mesenchymal protein, protects cultured intestinal epithelial cells from ROS. We therefore examine whether epimorphin protects primary cultured hepatocytes from ROS-induced cell injury.
  
  
  METHODS
  We explored the cell viability and the intracellular ROS levels of purified murine hepatocytes after exposure to 0.5 mM H(2)O(2) with or without pretreatment of epimorphin. Then, we observed mitochondrial permeability transition (MPT) and depolarization using confocal microscopy to make clear the mechanism that epimorphin inhibited cell injuries after exposure to H(2)O(2). In addition, to clarify the signaling pathways related to cell survival, we carried out Western blotting analysis with phosphorylated stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) polyclonal antibody to evaluate the inhibition of JNK by epimorphin. Finally, we evaluated the cell viability in hepatocytes administered JNK inhibitor.
  
  
  RESULTS
  Epimorphin protected primary cultured hepatocytes from H(2)O(2)-induced cell injuries independent of intracellular ROS levels. Epimorphin also inhibited onset of MPT, depolarization of the mitochondrial membrane potential, and eventually cell killing. The cell protective function of epimorphin after exposure to H(2)O(2) was not dependent on Akt signaling but on JNK signaling.
  
  
  CONCLUSIONS
  Epimorphin can protect hepatocytes from MPT-dependent cell injury induced by ROS. Since hepatic disorders could be caused by MPT-dependent cell injuries with excessive ROS, epimorphin might open a new therapeutic avenue for hepatic disorders.
authors.affiliation: Department of Gastroenterology, Akita University School of Medicine, Akita, Japan.
authors.forename: Nobukatsu
authors.initials: N
authors.lastname: Kinoshita
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Horie
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Ohshima
authors.forename: Yohei
authors.initials: Y
authors.lastname: Hirai
authors.forename: Takahiro
authors.initials: T
authors.lastname: Dohmen
authors.forename: Mario
authors.initials: M
authors.lastname: Jin
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Matsuhashi
authors.forename: Junko
authors.initials: J
authors.lastname: Sasaki
authors.forename: Takehiko
authors.initials: T
authors.lastname: Sasaki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iizuka
authors.forename: Hirohide
authors.initials: H
authors.lastname: Ohnishi
mesh_terms: D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019610:Cytoprotection; D005260:Female; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D048055:Mitogen-Activated Protein Kinase 8 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048056:Mitogen-Activated Protein Kinase 9 / Q000037:antagonists & inhibitors / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D050827:Syntaxin 1 / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000873:Anthracenes; D000975:Antioxidants; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D016877:Oxidants; D047428:Protein Kinase Inhibitors; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D050827:Syntaxin 1; C432165:pyrazolanthrone; D006861:Hydrogen Peroxide; D048056:Mitogen-Activated Protein Kinase 9; D048055:Mitogen-Activated Protein Kinase 8