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ERK signaling leads to mitochondrial dysfunction in extracellular zinc‐induced neurotoxicity
Author(s) -
He Kai,
Aizenman Elias
Publication year - 2010
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2010.06762.x
Subject(s) - mapk/erk pathway , microbiology and biotechnology , phosphorylation , neurotoxicity , kinase , extracellular , mitochondrion , p38 mitogen activated protein kinases , signal transduction , biology , programmed cell death , chemistry , biochemistry , apoptosis , toxicity , organic chemistry
J. Neurochem. (2010) 114 , 452–461. Abstract A zinc‐induced signaling pathway leading to extracellular signal‐regulated kinase 1/2 (ERK1/2) activation and subsequent neuronal death has been investigated. We find that an extracellular zinc application stimulates biphasic phosphorylation of ERK1/2 and p38 MAPK in rat cultured neurons. The activation of ERK1/2, but not p38, is responsible for zinc neurotoxicity as only U0126, a MEK inhibitor that blocks ERK1/2 phosphorylation, significantly protects cortical neurons from zinc exposure. Over‐expression of a dominant negative Ras mutant blocks zinc‐induced Elk1‐dependent gene expression in neurons, indicating the involvement of Ras activation in the zinc pathway leading to ERK phosphorylation and Elk1 signaling. We also find that zinc treatment results in neuronal mitochondrial hyperpolarization. Importantly, both U0126 and bongkrekic acid, an inhibitor of the mitochondrial adenine nucleotide translocase, effectively reduce zinc‐triggered mitochondrial changes. As bongkrekic acid also prevents zinc‐triggered neuronal death but not ERK1/2 phosphorylation, activation of MAPK signaling precedes and is required for mitochondrial dysfunction and cell death. These results provide new insight on the mechanism of extracellular zinc‐induced toxicity in which the regulation of mitochondrial function by the Ras/MEK/ERK pathway is closely associated with neuronal viability.