Daphnetin (Daph), a natural coumarin derivative isolated from plants of the Genus Daphne, possesses abundant biological activities, such as anti-inflammatory, antioxidant and anticancer properties. In the present study, we focused on investigating the protective effect of Daph against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage, mitochondrial dysfunction and the involvement of underlying molecular mechanisms. Our findings indicated that Daph effectively inhibited t-BHP-stimulated cytotoxicity, cell apoptosis, and mitochondrial dysfunction, which are associated with suppressed reactive oxygen species (ROS) generation, decreased malondialdehyde (MDA) formation, increased superoxide dismutase (SOD) levels and glutathione (GSH)/GSSG (oxidized GSH) ratio. Further investigation indicated that Daph significantly suppressed cytochrome c release and NLRP3 inflammasome activation and modulated apoptosis-related protein BcI-2, Box, and caspase-3 expression. Moreover, Daph dramatically induced the expression of the glutamate-cysteine ligase modifier (GCLM) subunit and the glutamate-cysteine ligase catalytic (GCLC) subunit, heme oxygenase-1 (H0-1), and NAD (P) H: quinone oxidoreductase (NQ01), which is largely dependent on upregulating the nuclear factor-erythroid 2-related factor 2 (Nrf2) nuclear translocation, reducing the Keapl protein expression, and strengthening the antioxidant response element (ARE) promoter activity. Additionally, Daph remarkably activated a c-Jun NH2terminal kinase (JNK) and extracellular signal-regulated kinase (ERIC) phosphorylation, but ERIC and JNK inhibitor pretreatment exhibited an evident decrease of the level of Daph-enhanced Nrf2 nuclear translocation. Furthermore, Daph exposure suppressed t-BHP-induced cytotoxicity and ROS overproduction, which are mostly blocked in Nrf2 knockout RAW 264.7 cells and peritoneal macrophages. Accordingly, Daph exhibited protective roles against t-BHP-triggered oxidative damage and mitochondrial dysfunction by the upregulation of Nrf2 antioxidant signaling pathways, which may be involved in the activation of JNK and ERIC.
[1]Jilin Univ, Inst Translat Med, Hosp 1, Changchun 130001, Peoples R China.
[2]Jilin Univ, Key Lab Zoonosis, Minist Educ, Coll Vet Medicine, Changchun 130061, Peoples R China.
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