The role of NF-kappaB in 6-hydroxydopamine- and TNFalpha-induced apoptosis of PC12 cells.
6-Hydroxydopamine (6-OHDA) is widely used to study the death of catecholaminergic cells related to Parkinson's disease. Oxidative stress and gene transcription are known to mediate the pro-apoptotic effect of 6-OHDA. As redox mechanisms are involved in activation of the transcription factor NF-kappaB, we studied the role of NF-kappaB in 6-OHDA-induced death of PC12 cells. We stably transfected PC12 cells with a doxycycline-regulated expression vector for the NF-kappaB super-repressor (IkappaBalpha mutated at serine-32 and serine-36, IkappaBalpha-SR). NF-kappaB transcriptional activity was evaluated by transient transfection of an NF-kappaB-driven luciferase reporter gene. Expression of IkappaBalpha-SR inhibited NF-kappaB stimulated by tumor necrosis factor alpha (TNFalpha) and 6-OHDA. Apoptosis was quantified by counting cells with condensed nuclei. IkappaBalpha-SR inhibited apoptosis induced by 6-OHDA but enhanced apoptosis that was triggered by TNFalpha. The converse effects of NF-kappaB could be due to different target genes that are induced in the context of TNFalpha and 6-OHDA stimulation. Indeed, TNFalpha stimulated mRNA accumulation of the anti-apoptotic superoxide dismutase 2 through NF-kappaB whereas 6-OHDA induced mRNA accumulation of the pro-apoptotic c-myc. These data demonstrate that NF-kappaB regulates survival of the neuron-like PC12 cells in a stimulus-specific manner. In the context of 6-OHDA stimulation, NF-kappaB mediates pro-apoptotic effects, suggesting that NF-kappaB signaling could be a target for drug development in Parkinson-related neurodegeneration.
Tarabin
Victoria
V
Department of Neurology, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
Schwaninger
Markus
M
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D004318:Doxycycline / Q000494:pharmacology; D020672:I-kappa B Proteins / Q000096:biosynthesis / Q000235:genetics; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D016627:Oxidopamine; D016716:PC12 Cells; D051381:Rats; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha
D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606206:Nfkbia protein, rat; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D016627:Oxidopamine; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D004318:Doxycycline