Phosphorylation of p38 MAPK Induced by Oxidative Stress Is Linked to Activation of Both Caspase-8- and -9-mediated Apoptotic Pathways in Dopaminergic Neurons

Won Seok Choi, Dae Seok Eom, Baek S. Han, Won-Ki Kim, Byung H. Han, Eui Ju Choi, Tae H. Oh, George J. Markelonis, Jin W. Cho, Young J. Oh

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We evaluated the contribution of p38 mitogen-activated protein kinase and the events upstream/down-stream of p38 leading to dopaminergic neuronal death. We utilized MN9D cells and primary cultures of mesencephalic neurons treated with 6-hydroxydopamine. Phosphorylation of p38 preceded apoptosis and was sustained in 6-hydroxydopamine-treated MN9D cells. Cotreatment with PD169316 (an inhibitor of p38) or expression of a dominant negative p38 was neuroprotective in death induced by 6-hydroxydopamine. The superoxide dismutase mimetic and the nitric oxide chelator blocked 6-hydroxydopamine-induced phosphorylation of p38, suggesting a role for superoxide anion and nitric oxide in eliciting a neurotoxic signal by activating p38. Following 6-hydroxydopamine treatment, inhibition of p38 prevented both caspase-8- and -9-mediated apoptotic pathways as well as generation of truncated Bid. Consequently, 6-hydroxydopamine-induced cell death was rescued by blockading activation of caspase-8 and -9. In primary cultures of mesencephalic neurons, the phosphorylation of p38 similarly appeared in tyrosine hydroxylase-positive, dopaminergic neurons after 6-hydroxydopamine treatment. This neurotoxin-induced phosphorylation of p38 was inhibited in the presence of superoxide dismutase mimetic or nitric oxide chelator. Co-treatment with PD169316 deterred 6-hydroxydopamine-induced loss of dopaminergic neurons and activation of caspase-3 in these neurons. Furthermore, inhibition of caspase-8 and -9 significantly rescued 6-hydroxydopamine-induced loss of dopaminergic neurons. Taken together, our data suggest that superoxide anion and nitric oxide induced by 6-hydroxydopamine initiate the p38 signal pathway leading to activation of both mitochondrial and extramitochondrial apoptotic pathways in our culture models of Parkinson's disease.

Original languageEnglish
Pages (from-to)20451-20460
Number of pages10
JournalJournal of Biological Chemistry
Issue number19
Publication statusPublished - 2004 May 7


ASJC Scopus subject areas

  • Biochemistry

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