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Del Nido Cardioplegia or Potassium Induces Nrf2 and Protects Cardiomyocytes Against Oxidative Stress

ABSTRACT: Open heart surgery is often an unavoidable procedure for treatment of coronary artery disease. The procedure associated reperfusion injury affects postoperative cardiac performance and long-term outcome. We addressed here whether cardioplegia essential for cardiopulmonary bypass surgery activates Nrf2, a transcription factor regulating the expression of antioxidant and detoxification genes. With commonly used cardioplegic solutions, High K+, Low K+, Del Nido (DN), histidine-tryptophan-ketoglutarate (HTK) and Celsior, we found that DN causes an increase of Nrf2 protein in AC16 human cardiomyocytes. Tracing the ingredients in DN led to the discovery of KCl at the concentration above 5 mM capable of Nrf2 protein induction. The Antioxidant Response Element luciferase reporter assay confirmed Nrf2 activation by DN or KCl. Transcriptomic profiling using RNA-seq revealed that oxidation-reduction as a main gene ontology group affected by KCl. KCl indeed elevated the expression of classical Nrf2 downstream targets, including TXNRD1, AKR1C, AKR1B1, SRXN1 and G6PD. DN or KCl induced Nrf2 elevation is Ca2+ concentration dependent. We found that KCl extended the half-life of Nrf2 from 17.8 to 25.1 mins, and decreased Nrf2 protein ubiquitination. Knocking out Keap1 blocked Nrf2 induction by K+. Nrf2 induction by DN or KCl protected against ROS generation or loss of viability by H2O2. Our data support that high K+ concentration in DN cardioplegic solution can induce Nrf2 protein, which in turn mediates protection of cardiomyocytes

ORGANISM(S): Homo sapiens

PROVIDER: GSE221058 | GEO | 2023/01/01

REPOSITORIES: GEO

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Project description:Long wavelength Ultraviolet (UVA-1) radiation causes oxidative stress that leads to the formation of noxious substances within the skin. As a defensive mechanism skin cells produce detoxifying enzymes and antioxidants when they detect modified molecules. We have recently shown that UVA-1 irradiation oxidizes the abundant membrane phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC), which then induced the synthesis of the stress response protein heme oxygenase 1 (HO-1) in dermal fibroblasts. Here we examined the effects of UVA-1 and (UV-) oxidized phospholipids on the global gene expression in human dermal fibroblasts. We identified a cluster of genes that were co-induced by UVA-1-oxidized PAPC and UVA-1 radiation. The cluster included HO-1, glutamate-cysteine ligase modifier subunit (GCLM), aldo-keto reductases-1-C1 and -C2 (AKR1C1, AKR1C2), and interleukin 8 (IL8). These genes are members of the cellular stress response system termed âantioxidant responseâ or âPhase II detoxificationâ. Accordingly, the regulatory regions of all these genes contain binding sites for NF-E2-related factor 2 (Nrf2), a major regulator of the antioxidant response. Both UVA-1 irradiation and treatment with oxidized lipids led to increased nuclear accumulation of Nrf2. Silencing expression of Nrf2 using siRNA or using cells and tissue from Nrf2-deficient mice, we show that the induction of the co-regulated genes was suppressed. Expression of other canonical UVA-1-induced genes, including cyclooxygenase 2 (Cox2) and interleukin 6 (IL6) was unaltered in the absence of Nrf2. Together, our data show that UVA-1-mediated lipid oxidation induces induction of antioxidant response genes, which is dependent on the redox-regulated transcription factor Nrf2. To activate Nrf2 is a major strategy for novel antioxidant drugs, the skin photo-adaptation (SPA) inducers. Our finding that specific uv-oxidized lipids act similar sheds a new (ultraviolet) light on the usually detrimental âimageâ of UV generated lipid mediators. Experiment Overall Design: we profiled global mRNA expression levels in human dermal fibroblasts that had been treated with either UVA-1 or oxidized lipids. To investigate the effect of oxidized phospholipids on gene regulation, we used two preparations, which differed in their degree of oxidation; the minimally oxidized UV-PAPC resulting from UVA-1 irradiation of PAPC, and air-oxidized PAPC (OxPAPC), which represents the full spectrum of oxidation products (Gruber 07) (Reis et al., 2005). We irradiated dermal fibroblasts with UVA-1 (40J/cmÂ²) or treated them with UV-PAPC, OxPAPC or native PAPC (100Âµg/ml each). We analyzed global gene expression four hours after stimulation with gene arrays (Affymetrix U133A Plus 2.0 Gene Chips).

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Del Nido Cardioplegia or Potassium Induces Nrf2 and Protects Cardiomyocytes Against Oxidative Stress

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