TY - JOUR
T1 - 6-Hydroxydopamine induces mitochondrial ERK activation
AU - Kulich, Scott M.
AU - Horbinski, Craig
AU - Patel, Manisha
AU - Chu, Charleen T.
N1 - Funding Information:
We thank Amy Sartori, Charlotte Diges, Prajakta Sonalker, and Jianhui Zhu for technical assistance. We thank Incara Pharmaceuticals (Research Triangle Park, NC) for providing AEOL 11013. This work was supported by a Veterans Administration Advanced Research Career Development Award (S.M.K.), the National Institutes of Health NS40817, NS053777, AG026389 (C.T.C.), NS045748 (M.P.), and the University of Pittsburgh Pathology Post-doctoral Research Training Program (S.M.K.).
PY - 2007/8/1
Y1 - 2007/8/1
N2 - Reactive oxygen species (ROS) are implicated in 6-hydroxydopamine (6-OHDA) injury to catecholaminergic neurons; however, the mechanism(s) are unclear. In addition to ROS generated during autoxidation, 6-OHDA may initiate secondary cellular sources of ROS that contribute to toxicity. Using a neuronal cell line, we found that catalytic metalloporphyrin antioxidants conferred protection if added 1 h after exposure to 6-OHDA, whereas the hydrogen peroxide scavenger catalase failed to protect if added more than 15 min after 6-OHDA. There was a temporal correspondence between loss of protection and loss of the ability of the antioxidant to inhibit 6-OHDA-induced ERK phosphorylation. Time course studies of aconitase inactivation, an indicator of intracellular superoxide, and MitoSOX red, a mitochondria targeted ROS indicator, demonstrate early intracellular ROS followed by a delayed phase of mitochondrial ROS production, associated with phosphorylation of a mitochondrial pool of ERK. Furthermore, on initiation of mitochondrial ROS and ERK activation, 6-OHDA-injured cells became refractory to rescue by metalloporphyrin antioxidants. Together with previous studies showing that inhibition of the ERK pathway confers protection from 6-OHDA toxicity, and that phosphorylated ERK accumulates in mitochondria of degenerating human Parkinson's disease neurons, these studies implicate mitochondrial ERK activation in Parkinsonian oxidative neuronal injury.
AB - Reactive oxygen species (ROS) are implicated in 6-hydroxydopamine (6-OHDA) injury to catecholaminergic neurons; however, the mechanism(s) are unclear. In addition to ROS generated during autoxidation, 6-OHDA may initiate secondary cellular sources of ROS that contribute to toxicity. Using a neuronal cell line, we found that catalytic metalloporphyrin antioxidants conferred protection if added 1 h after exposure to 6-OHDA, whereas the hydrogen peroxide scavenger catalase failed to protect if added more than 15 min after 6-OHDA. There was a temporal correspondence between loss of protection and loss of the ability of the antioxidant to inhibit 6-OHDA-induced ERK phosphorylation. Time course studies of aconitase inactivation, an indicator of intracellular superoxide, and MitoSOX red, a mitochondria targeted ROS indicator, demonstrate early intracellular ROS followed by a delayed phase of mitochondrial ROS production, associated with phosphorylation of a mitochondrial pool of ERK. Furthermore, on initiation of mitochondrial ROS and ERK activation, 6-OHDA-injured cells became refractory to rescue by metalloporphyrin antioxidants. Together with previous studies showing that inhibition of the ERK pathway confers protection from 6-OHDA toxicity, and that phosphorylated ERK accumulates in mitochondria of degenerating human Parkinson's disease neurons, these studies implicate mitochondrial ERK activation in Parkinsonian oxidative neuronal injury.
KW - 6-Hydroxydopamine
KW - Extracellular signal-regulated MAP kinases
KW - Mitochondria
KW - Parkinson's disease
KW - Reactive oxygen species
UR - http://www.scopus.com/inward/record.url?scp=34250891417&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34250891417&partnerID=8YFLogxK
U2 - 10.1016/j.freeradbiomed.2007.04.028
DO - 10.1016/j.freeradbiomed.2007.04.028
M3 - Article
C2 - 17602953
AN - SCOPUS:34250891417
SN - 0891-5849
VL - 43
SP - 372
EP - 383
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
IS - 3
ER -