Inhibition of ROS-induced apoptosis in endothelial cells by nitrone spin traps via induction of phase II enzymes and suppression of mitochondria-dependent pro-apoptotic signaling

Abstract

Oxidative stress is the main etiological factor behind the pathogenesis of various diseases including inflammation, cancer, cardiovascular and neurodegenerative disorders. Due to the spin trapping abilities and various pharmacological properties of nitrones, their application as therapeutic agent has been gaining attention. Though the antioxidant properties of the nitrones are well known, the mechanisms by which they modulate the cellular defense machinery against oxidative stress is not well investigated and requires further elucidation. Here, we have investigated the mechanisms of cytoprotection of the nitrone spin traps against oxidative stress in bovine aortic endothelial cells (BAEC). Cytoprotective properties of both the cyclic nitrone 5,5-dimethyl-pyrroline N-oxide (DMPO) and linear nitrone alpha-phenyl N-tert-butyl nitrone (PBN) against H2O2-induced cytoxicity were investigated. Preincubation of BAEC with PBN or DMPO resulted in the inhibition of H2O2–mediated cytotoxicity and apoptosis. Nitrone-treatment resulted in the induction and restoration of phase II antioxidant enzymes via nuclear translocation of NF-E2-related factor 2 (Nrf-2) in oxidatively-challenged cells. Furthermore, the nitrones were found to inhibit the mitochondrial depolarization and subsequent activation of caspase-3 induced by H2O2. Significant down-regulation of the pro-apoptotic proteins p53 and Bax, and up-regulation of the anti-apoptotic proteins Bcl-2 and p-Bad were observed when the cells were preincubated with the nitrones prior to H2O2–treatment. It was also observed that Nrf-2 silencing completely abolished the protective effects of nitrones. Hence, these findings suggest that nitrones confer protection to the endothelial cells against oxidative stress by modulating phase II antioxidant enzymes and subsequently inhibiting mitochondria-dependent apoptotic cascade.

LYG-202 exerts antitumor effect on PI3K/Akt signaling pathway in human breast cancer cells

“…It has been reported that oxidative stress is an important factor causing mitochondrial dysfunction, which leads to excessive generation of ROS and the imbalance of oxidation system and antioxidation system [30]. To elucidate the underlying mechanisms of LYG-202 on mitochondrial dysfunction in MCF-7 cells, we examined the effect of LYG-202 on ROS generation.…”

A Mouse Model of Peripheral Postischemic Dysesthesia: Involvement of Reperfusion-Induced Oxidative Stress and TRPA1 Channel

“…We examined the effects of intraplantar injection of another antioxidant, phenyl-N-tert-butylnitrone (Das et al, 2012), on licking induced by H 2 O 2 injection and ischemia-reperfusion to confirm the role of ROS production in the paw distal to the compression site. Intraplantar injections of phenyl-N-tert-butylnitrone (10 and 100 mg/site) together with 0.3% H 2 O 2 dose dependently and significantly (one-way ANOVA; F 2,18 5 11.661, P , 0.001) inhibited H 2 O 2 -induced licking, with a significant inhibition (Dunnett's test; P , 0.05) observed at a dose of 100 mg/site (Fig.…”

On the vasoprotective mechanisms underlying novel β-phosphorylated nitrones: Focus on free radical characterization, scavenging and NO-donation in a biological model of oxidative stress

“…Although the therapeutic efficacy of PBN-type nitrones (PBNs) in systems exposed to ROS may be consistently relevant to free radical scavenging, other mechanisms have been highlighted, such as iNOS and COX-2 gene induction suppression [14], modulation of phase II enzymes and caspase-3 activities [15] or activation of Ras-ERK pathway [16]. Moreover, in aqueous media, PBN [17] and other nitrones were shown to release nitric oxide (NO), a free radical implicated in both physiological and stressrelated signaling.…”