Activation of p53 and the pro-apoptotic p53 target gene PUMA during depolarization-induced apoptosis of chromaffin cells.
The pathogenesis of non-glutamatergic, depolarization-induced cell death is still enigmatic. Recently, we have shown that veratridine induces apoptosis in chromaffin cells, and we have demonstrated protective effects of antioxidants in this system, suggesting a role for Na+ channels and oxidative stress in depolarization-induced cell death. We examined the possible contribution of p53, a transcription factor that has a major role in determining cell fate, and the mitochondrial apoptosis pathway in veratridine-induced cell death of cultured bovine chromaffin cells. Nuclear condensation and fragmentation were detected several hours after a 60-min exposure to 30 microM veratridine. Apoptosis was associated with a transitory increase in p53 protein levels. Veratridine induced transcription of the pro-apoptotic p53 target gene PUMA, but not of bax or pig3. Using transient transfection experiments, we found that wild-type p53, but not the mutant form p53-273H, was sufficient to induce cell death in the chromaffin cells, which was caspase-9 dependent. The down-regulation of either p53, by overexpressing p53-273H, or caspase-9 activity using a dominant-negative caspase-9 mutant protected chromaffin cells against veratridine-induced toxicity. Our data demonstrate the importance of p53 and the downstream activation of the mitochondrial apoptosis pathway in depolarization-induced apoptosis.
Gomez-Lazaro
M
M
Departamento de Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Avda. Almansa, s/n, 02006 Albacete, Spain.
Galindo
M F
MF
Fernandez-Gomez
F J
FJ
Prehn
J H M
JH
Jordán
J
J
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000187:drug effects / Q000473:pathology*; D004591:Electrophoresis, Polyacrylamide Gel; D016158:Genes, p53 / Q000187:drug effects / Q000502:physiology*; D015151:Immunoblotting; D007150:Immunohistochemistry; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000187:drug effects / Q000502:physiology*; D014701:Veratridine / Q000633:toxicity
D025521:Tumor Suppressor Proteins; D014701:Veratridine