NF-E2-related factor-2 mediates neuroprotection against mitochondrial complex I inhibitors and increased concentrations of intracellular calcium in primary cortical neurons.
NF-E2-related factor-2 (Nrf2) regulates the gene expression of phase II detoxification enzymes and antioxidant proteins through an enhancer sequence referred to as the antioxidant-responsive element (ARE). In this study, we demonstrate that Nrf2 protects neurons in mixed primary neuronal cultures containing both astrocytes ( approximately 10%) and neurons ( approximately 90%) through coordinate up-regulation of ARE-driven genes. Nrf2-/- neurons in this mixed culture system were more sensitive to mitochondrial toxin (1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine or rotenone)-induced apoptosis compared with Nrf2+/+ neurons. To understand the underlying mechanism of this observed differential sensitivity, we compared the gene expression profiles using oligonucleotide microarrays. Microarray data showed that Nrf2+/+neuronal cultures had higher expression levels of genes encoding detoxification enzymes, antioxidant proteins, calcium homeostasis proteins, growth factors, neuron-specific proteins, and signaling molecules compared with Nrf2-/- neuronal cultures. As predicted from the microarray data, Nrf2-/- neurons were indeed more vulnerable to the cytotoxic effects of ionomycin- and 2,5-di-(t-butyl)-1,4-hydroquinone-induced increases in intracellular calcium. Finally, adenoviral vector-mediated overexpression of Nrf2 recovered ARE-driven gene expression in Nrf2-/- neuronal cultures and rescued Nrf2-/- neurons from rotenone- or ionomycin-induced cell death. Taken together, these findings suggest that Nrf2 plays an important role in protecting neurons from toxic insult.
Lee
Jong-Min
JM
School of Pharmacy, University of Wisconsin, Madison 53705-2222, USA.
Shih
Andy Y
AY
Murphy
Timothy H
TH
Johnson
Jeffrey A
JA
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000502:physiology*; D042967:Electron Transport Complex I / Q000037:antagonists & inhibitors* / Q000235:genetics; D006706:Homeostasis; D051379:Mice; D051267:NF-E2-Related Factor 2; D018696:Neuroprotective Agents; D018384:Oxidative Stress; D020218:Response Elements; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012402:Rotenone / Q000633:toxicity; D015534:Trans-Activators / Q000502:physiology*
D000975:Antioxidants; D004268:DNA-Binding Proteins; D051267:NF-E2-Related Factor 2; D018696:Neuroprotective Agents; C495636:Nfe2l2 protein, mouse; D015534:Trans-Activators; D012402:Rotenone; D042967:Electron Transport Complex I; D015655:1-Methyl-4-phenylpyridinium; D002118:Calcium