Ezetimibe Prevents Ischemia/Reperfusion-Induced Oxidative Stress and Up-Regulates Nrf2/ARE and UPR Signaling Pathways

Abstract

Background: While reperfusion is crucial for survival after an episode of ischemia, it also causes oxidative stress. Nuclear factor-E2-related factor 2 (Nrf2) and unfolded protein response (UPR) are protective against oxidative stress and endoplasmic reticulum (ER) stress. Ezetimibe, a cholesterol absorption inhibitor, has been shown to activate the AMP-activated protein kinase (AMPK)/Nrf2 pathway. In this study we evaluated whether Ezetimibe affects oxidative stress and Nrf2 and UPR gene expression in cellular models of ischemia-reperfusion (IR). Methods: Cultured cells were subjected to simulated IR with or without Ezetimibe. Results: IR significantly increased reactive oxygen species (ROS) production and the percentage of apoptotic cells without the up-regulation of Nrf2, of the related antioxidant response element (ARE) gene expression or of the pro-survival UPR activating transcription factor 6 (ATF6) gene, whereas it significantly increased the pro-apoptotic CCAAT-enhancer-binding protein homologous protein (CHOP). Ezetimibe significantly decreased the cellular ROS formation and apoptosis induced by IR. These effects were paralleled by the up-regulation of Nrf2/ARE and ATF6 gene expression and by a down-regulation of CHOP. We also found that Nrf2 activation was dependent on AMPK, since Compound C, a pan inhibitor of p-AMPK, blunted the activation of Nrf2. Conclusions: Ezetimibe counteracts IR-induced oxidative stress and induces Nrf2 and UPR pathway activation.

The Cell Protective Effect of Adenine on Hypoxia–Reoxygenation Injury through PPAR Delta Activation

“…Activation of AMPK was shown to inhibit ER stress in previous studies [19,20]. Ezetimibe, a cholesterol absorption inhibitor, was shown to reduce IR-induced oxidative stress and UPR pathway activation through activation of AMPK [22]. Pang et al proved that CAMKKβ/AMPK/mTOR-dependent signaling pathway was critical for inhibiting ER stress in cardiomyocytes [23].…”

Ameliorative Effects of the Sesquiterpenoid Valerenic Acid on Oxidative Stress Induced in HepG2 Cells after Exposure to the Fungicide Benomyl

“…Noteworthily, ERN-1 is an NF-κB activator that provides connections between ER stress, oxidative stress, and inflammatory processes between the cell death process [59]. It has been reported that oxidative and ER stress interplay through Nrf2 activation is crucial for cellular events, such as apoptosis and cell survival [60]. Figure 8.…”

Intracellular Polyphenol Wine Metabolites Oppose Oxidative Stress and Upregulate Nrf2/ARE Pathway

“…Human cardiomyocyte ventricular primary cells (Celprogen, Torrance, CA, USA) were cultured following the recommended manufacturer’s protocols in extracellular matrix pre-coated flasks and/or well plates with a ready-to-use complete growth medium (Celprogen, Torrance, CA, USA), as previously described [ 37 ]. The choice of such cell lines was guided by previous evidence of their high reliability in evaluating oxidative stress and antioxidant signaling pathways [ 38 , 39 ] .…”

“…To induce different degrees of oxidative stress, THP-1 cells were incubated with increasing concentrations (20–100 μM) of tert-butyl hydroperoxide (TBHP) for 45 min at 37 °C. Intracellular ROS formation was determined using the CellROX Deep Red Flow Cytometry Assay Kit (Molecular Probe, Life Technologies, Carlsbad, CA, USA), as previously described [ 38 ]. Briefly, the cell-permeable CellROX Deep Red reagent is essentially non-fluorescent while it is in a reduced state, but exhibits a strong fluorogenic signal upon oxidation, providing a reliable measure of ROS in live cells [ 41 ].…”