title: Identification of a lipid peroxidation product as a potential trigger of the p53 pathway.
abstract: The tumor suppressor and transcription factor p53 is a key modulator of cellular stress responses, and activation of p53 can trigger apoptosis in many cell types, including neurons. We found that this nuclear protein was significantly phosphorylated when human neuroblastoma SH-SY5Y cells were exposed to in vitro oxidized polyunsaturated fatty acids. To identify an oxidized lipid that induces p53 phosphorylation, we conducted a screening of lipid peroxidation products in human neuroblastoma SH-SY5Y cells and identified 4-oxo-2-nonenal (ONE), a recently identified aldehyde originating from the peroxidation of omega6 polyunsaturated fatty acids, as a potential inducer of the p53 phosphorylation. We also found that ONE induced the phosphorylation of ataxia telangiectasia-mutated, which plays an essential role in transmitting DNA damage signals by the phosphorylation of p53. In addition, exposure of the cells to ONE resulted in an accumulation of ubiquitinated proteins and in a significant inhibition of proteasome activities, suggesting that ONE acted on the ubiquitin-proteasome pathway, a regulatory mechanism of p53 turnover. In addition, the observation that the ONE-induced p53 response was associated with the induction of apoptosis suggested that ONE activated the p53-dependent apoptosis mechanism via activation of the p53 signaling pathway and down-regulation of the p53 turnover. Finally, we observed that the ONE-2'-deoxyguanosine adduct, 7-(2-oxo-heptyl)-substituted 1,N(2)-etheno-2'-deoxyguanosine, was accumulated in the spinal cord motor neurons of patients with sporadic amyotrophic lateral sclerosis. These data may suggest the potential critical role for ONE in the induction of a neuronal apoptosis program during oxidative processes.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shibata
authors.forename: Kumiko
authors.initials: K
authors.lastname: Iio
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Kawai
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Shibata
authors.forename: Motoko
authors.initials: M
authors.lastname: Kawaguchi
authors.forename: Sono
authors.initials: S
authors.lastname: Toi
authors.forename: Makio
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Koji
authors.initials: K
authors.lastname: Uchida
mesh_terms: D000447:Aldehydes / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis; D064007:Ataxia Telangiectasia Mutated Proteins; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D053938:DNA Fragmentation; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D015227:Lipid Peroxidation; D008956:Models, Chemical; D009447:Neuroblastoma / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism
chemical_list: C403894:4-oxo-2-nonenal; D000447:Aldehydes; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005231:Fatty Acids, Unsaturated; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D025801:Ubiquitin; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D046988:Proteasome Endopeptidase Complex; D010100:Oxygen