Paraquat exposure induces nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the activation of the nitric oxide-GAPDH-Siah cell death cascade.
Paraquat (PQ) is a well-known herbicide that exerts its effects by elevating intracellular levels of superoxide. It has been previously demonstrated that oxidative and nitrosative stress participate to PQ-induced cell death. Here, we document that PQ increases the levels of nitric oxide (NO) in rat mesencephalic cells and causes nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) to activate the NO/GAPDH/Siah cell death cascade. PQ exposure increases expression of the p300/CREB-binding protein (p300/CBP) and phosphorylation of p53 at Ser 15, which stimulates p53-dependent transactivation through increased binding with p300. Although this cascade could be inhibited by preincubation with the monoamine oxidase B inhibitor deprenyl, cell death was not prevented. Pretreatment of cells with the neuronal nitric oxide synthase inhibitor 7-nitroindazole efficiently prevented the activation of the GAPDH/NO/Siah cell death cascade, thereby protecting cells against PQ-induced toxicity. The results suggest that PQ induces this novel cell death cascade in rat mesencephalic cells, but inhibition of the pathway does not impede cell death because of an oxidative burst generated by the pesticide.
Ortiz-Ortiz
Miguel A
MA
Departamento de Bioquímica y Biología Molecular y Genética, EU Enfermería y Terapia Ocupacional, Universidad de Extremadura, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Cáceres, Spain.
Morán
José M
JM
Ruiz-Mesa
Luz M
LM
Bravo-San Pedro
José M
JM
Fuentes
José M
JM
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity; D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D006540:Herbicides / Q000633:toxicity*; D009569:Nitric Oxide / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism*; D010269:Paraquat / Q000633:toxicity*; D010766:Phosphorylation; D051381:Rats; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D050880:p300-CBP Transcription Factors / Q000378:metabolism; D000098563:Seven in Absentia Proteins
D006540:Herbicides; D009687:Nuclear Proteins; D016159:Tumor Suppressor Protein p53; D009569:Nitric Oxide; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D050880:p300-CBP Transcription Factors; D044767:Ubiquitin-Protein Ligases; D000098563:Seven in Absentia Proteins; D010269:Paraquat; D015655:1-Methyl-4-phenylpyridinium