title: Temporal activation of Nrf2 in the penumbra and Nrf2 activator-mediated neuroprotection in ischemia-reperfusion injury.
abstract: Oxidative stress plays a critical role in mediating tissue injury and neuron death during ischemia-reperfusion injury (IRI). The Keap1-Nrf2 defense pathway serves as a master regulator of endogenous antioxidant defense, and Nrf2 has been attracting attention as a target for the treatment of IRI. In this study, we evaluated Nrf2 expression in IRI using OKD (Keap1-dependent oxidative stress detector) mice and investigated the neuroprotective ability of an Nrf2 activator. We demonstrated temporal changes in Nrf2 expression in the same mice with luciferase assays and an Nrf2 activity time course using Western blotting. We also visualized Nrf2 expression in the ischemic penumbra and investigated Nrf2 expression in mice and humans using immunohistochemistry. Endogenous Nrf2 upregulation was not detected early in IRI, but expression peaked 24h after ischemia. Nrf2 expression was mainly detected in the penumbra, and it was found in neurons and astrocytes in both mice and humans. Intravenous administration of the Nrf2 activator bardoxolone methyl (BARD) resulted in earlier upregulation of Nrf2 and heme oxygenase-1. Furthermore, BARD decreased infarction volume and improved neurological symptoms after IRI. These findings indicate that earlier Nrf2 activation protects neurons, possibly via effects on astrocytes.
authors.affiliation: Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu 501-1196, Japan; Department of Neurosurgery, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Takagi
authors.affiliation: Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kitashoji
authors.affiliation: Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi City, Gunma 371-8511, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Iwawaki
authors.affiliation: Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tsuruma
authors.affiliation: Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Shimazawa
authors.affiliation: Department of Neurosurgery, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yoshimura
authors.affiliation: Department of Neurosurgery, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Iwama
authors.affiliation: Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu 501-1196, Japan. Electronic address: hidehara@gifu-pu.ac.jp.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Hara
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D015153:Blotting, Western; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009828:Oleanolic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D015427:Reperfusion Injury / Q000378:metabolism* / Q000473:pathology
chemical_list: D051267:NF-E2-Related Factor 2; D018696:Neuroprotective Agents; D009828:Oleanolic Acid; C445068:bardoxolone methyl
keywords: Bardoxolone methyl; Free radicals; Ischemia–reperfusion injury; Neuroprotection; Nrf2; Oxidative stress