Administration of the Nrf2–ARE activators sulforaphane and carnosic acid attenuates 4-hydroxy-2-nonenal-induced mitochondrial dysfunction ex vivo

Abstract

The transcription factor NF-E2-related factor 2 (Nrf2) mediates transcription of antioxidant/cytoprotective genes by binding to the antioxidant response element (ARE) within DNA. Upregulation of these genes constitutes a pleiotropic cytoprotective-defense pathway which has been shown to produce neuroprotection in numerous models by decreasing lipid peroxidation (LP) as measured by the neurotoxic LP by-product 4-hyrdoxynonenal (4-HNE). As neuronal mitochondria have previously been shown to be susceptible to insult-induced LP-mediated oxidative damage, we sought to mechanistically investigate whether Nrf2-ARE activation in vivo could protect mitochondria from subsequent 4-HNE exposure ex vivo. Young adult male CF-1 mice were administered one of two known Nrf2-ARE activators as single I.P. doses – sulforaphane (SFP; 5.0 mg/kg) or carnosic acid (CA; 1.0mg/kg) – or their respective vehicles 48 hours prior to Ficoll isolation of rat cerebral cortical mitochondria. Purified mitochondria were then exposed ex vivo to 4-HNE for 15 minutes at 37°C which we showed to cause a concentration-related inhibition of mitochondrial respiration together with covalent binding of 4-HNE to mitochondrial proteins. We chose a 30 μM concentration of 4-HNE, which produced an approximate 50% inhibition of complex I or complex II-driven respiration, to assess whether prior in vivo the Nrf2-ARE activating compounds would increase the resistance of the isolated cortical mitochondria to 4-HNE's mito-toxic effects. Administration of either compound significantly increased (p< 0.05) expression of heme oxygenase-1 mRNA in cortical tissue 48 hours post-administration, verifying that both compounds were capable of inducing the Nrf2-ARE pathway. Moreover, the prior in vivo administration of sulforaphane (SFP) and carnosic acid (CA) significantly (p< 0.05) attenuated 4-HNE-induced inhibition of mitochondrial respiration for complex I while only carnosic acid acted to protect complex II. Furthermore, both CA and SFP significantly (p< 0.05) reduced the amount of 4-HNE bound to mitochondria proteins as determined by Western blot. These results demonstrate the capability of Nrf2-ARE induction in vivo to protect from 4-HNE toxicity to cortical mitochondria ex vivo. Ongoing studies will determine the therapeutic efficacy of Nrf2-ARE activators to attenuate traumatic brain injury induced pathophysiology.

Umbilical Cord MSCs Reverse D-Galactose-Induced Hepatic Mitochondrial Dysfunction <i>via</i> Activation of Nrf2/HO-1 Pathway

“…30) In the present study, the synchronous decreases or increases of mitochondrial antioxidative enzymes by D-Gal treatment or UC-MSCs supplementation underlined the involvement of Nrf2/HO-1. Indeed, the Western-blot results demonstrated that the Nrf2/HO-1 activity was inhibited in D-Gal models, on which UC-MSCs treatment showed effective protection on Nrf2/HO-1, suggesting that Nrf2/HO-1 pathway was one target of UC-MSCs in the mitochondrial protective process.…”

Sulforaphane Decreases Endothelial Cell Apoptosis in Fuchs Endothelial Corneal Dystrophy: A Novel Treatment

“…27 Specifically, SFN-induced activation of ARE has been shown to prevent cell death from oxidative insults and glutamate toxicity in neuronal cells, from photooxidative damage 28 and oxidative stress 29 in retinal pigment epithelial cells, and from electrophilic stress in rat aortic, smooth muscle cells. 30 Moreover, animal models have been developed to evaluate Nrf2-ARE cytoprotection, [31][32][33] and numerous clinical studies have utilized SFN for treatment of prostate cancer, cystic fibrosis, cardiovascular disease, and asthma, among many others (ClinicalTrials.gov). [19][20][21] Thus, there is considerable evidence supporting the notion that activation of the Nrf2 pathway could be a useful therapeutic target for treating chronic degenerative conditions such as FECD.…”

Melatonin protects against burn-induced hepatic oxidative injury by inducing HO-1 via the Nrf2 pathway

“…A possible mechanism by which melatonin increases Nrf2 expression is related to the dissociation of Nrf2/ Keap 1 (repressor) and translocation of Nrf2 to the nucleus, where it binds to the ARE in the promoters of the genes involved in antioxidant protection such as SOD, catalase, GxP and HO-1 (Jaiswal 2004;Osburn et al 2006). It has been reported that Nrf2 activators protect from oxidative injury (Chan et al 2001;Farombi et al 2008;Miller et al 2013). We suggest that melatonin can ameliorate burn-induced liver injury through inhibition of free-radical activating lipid peroxidation, and via the elevation of expression of the transcription factor Nrf2 and antioxidant enzymes such as HO-1.…”