title: Vacuolar H+ -ATPase c protects glial cell death induced by sodium nitroprusside under glutathione-depleted condition.
abstract: We examined the role of the c subunit (ATP6L) of vacuolar H(+) -ATPase and its molecular mechanisms in glial cell death induced by sodium nitroprusside (SNP). ATP6L siRNA-transfected cells treated with SNP showed a significant increase in cytotoxicity under glutathione (GSH)-depleted conditions after pretreatment with buthionine sulfoximine, but reduction of ATP6L did not affect the regulation of lysosomal pH in analyses with lysosomal pH-dependent fluorescence probes. Photodegraded SNP and ferrous sulfate induced cytotoxicity with the same pattern as that of SNP, but SNAP and potassium cyanide did not show activity. Pretreatment of the transfected cells with deferoxamine (DFO) reduced ROS production and significantly inhibited the cytotoxicity, which indicates that primarily iron rather than nitric oxide or cyanide from SNP contributes to cell death. Involvement of apoptotic processes in the cells was not shown. Pretreatment with JNK or p38 chemical inhibitor significantly inhibited the cytotoxicity, and we also confirmed that the MAPKs were activated in the cells by immunoblot analysis. Significant increase of LC3-II conversion was observed in the cells, and the conversions were inhibited by cotransfection of the MAPK siRNAs and pretreatment with DFO. Introduction of Atg5 siRNA inhibited the cytotoxicity and inhibited the activation of MAPKs and the conversion of LC3. We finally confirmed autophagic cell death and involvement of MAPKs by observation of autophagic vacuoles via electron microscopy. These data suggest that ATP6L has a protective role against SNP-induced autophagic cell death via inhibition of JNK and p38 in GSH-depleted glial cells.
authors: Department of Biochemistry, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, Korea.
authors: Yu Jeong
authors: YJ
authors: Byun
authors: Seong-Beom
authors: SB
authors: Lee
authors: Hwa Ok
authors: HO
authors: Lee
authors: Min Jeong
authors: MJ
authors: Son
authors: Ho-Shik
authors: HS
authors: Kim
authors: Oh-Joo
authors: OJ
authors: Kwon
authors: Seong-Whan
authors: SW
authors: Jeong
mesh_terms: D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics; D005978:Glutathione; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000201:enzymology / Q000648:ultrastructure; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009457:Neuroglia / Q000201:enzymology* / Q000648:ultrastructure; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: C541389:ATP6V0C protein, human; D020030:Nitric Oxide Donors; D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D009599:Nitroprusside; D019328:Buthionine Sulfoximine; D020929:Mitogen-Activated Protein Kinase Kinases; D025262:Vacuolar Proton-Translocating ATPases; D005978:Glutathione