title: Cadmium induces neuronal cell death through reactive oxygen species activated by GADD153.
abstract: BACKGROUND
  Cadmium(Cd), a heavy metal, which has a potent harmful effects, is a highly stress-inducible material that is robustly expressed following disruption of homeostasis in the endoplasmic reticulum (ER) (so-called ER stress). The mechanism Cd induced cell death of neuroblastoma cells complex, involving cellular signaling pathways as yet incompletely defined but, in part, involving the generation of reactive oxygen species (ROS). Several studies have correlated GADD153 expression with cell death, but a mechanistic link between GADD153 and apoptosis has never been demonstrated.
  
  
  RESULTS
  SH-SY5Y cells were treated Cd led to increase in intracellular ROS levels. ROS generation is not consistent with intracellular [Ca2+]. The exposure of neuroblastoma cells to Cd led to increase in intracellular GADD153 and Bak levels in a doses and time dependent manner. The induction of these genes by Cd was attenuated by NAC. Cd-induced apoptosis is decreased in GADD153 knockdown cells compared with normal cells. The effect of GADD153 on the binding of C/EBP to the Bak promoters were analyzed ChIP assay. Basal constitutive GADD153 recruitment to the -3,398/-3,380 region of the Bak promoter is observed in SH-SY5Y cells.
  
  
  CONCLUSIONS
  The exposure of SH-SY5Y cells to Cd led to increase in intracellular ROS levels in a doses and time dependent manner. The generation of ROS result in the induction of GADD153 is causative of cadmium-induced apoptosis. GADD153 regulates Bak expression by its binding to promoter region (between -3,398 and -3,380). Therefore, we conclude that GADD153 sensitizes cells to ROS through mechanisms that involve up-regulation of BAK and enhanced oxidant injury.
authors: Center for Biomedical Science, Division of Brain Diseases, National Institute of Health in Korea (KNIH), Osong Health Technology Administration Complex, 187 songsaengmyeong2(i)-ro, Gangoe-myeon, Cheongwon-gun, Chungcheongbuk-do, 363-951, Korea.
authors: Seungwoo
authors: S
authors: Kim
authors: Hyo-Soon
authors: HS
authors: Cheon
authors: So-Young
authors: SY
authors: Kim
authors: Yong-Sung
authors: YS
authors: Juhnn
authors: Young-Youl
authors: YY
authors: Kim
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism; D002104:Cadmium / Q000737:chemistry / Q000633:toxicity*; D045744:Cell Line, Tumor; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000187:drug effects; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D051742:Transcription Factor CHOP / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D016166:Free Radical Scavengers; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D050998:bcl-2 Homologous Antagonist-Killer Protein; D002104:Cadmium; D051742:Transcription Factor CHOP; D000111:Acetylcysteine