Glutaredoxin 2 protects cardiomyocytes from hypoxia/reoxygenation-induced injury by suppressing apoptosis, oxidative stress, and inflammation via enhancing Nrf2 signaling

Expression and purification of recombinant glutaredoxin 1 and protection against oxidative stress injury during cerebral ischemia-reperfusion injury

Glutaredoxin (Grx) is a small molecular protein widely found in both prokaryotes and eukaryotes, serving various biological functions, including participation in redox reactions and exerting anti-apoptotic effects[1]. To evaluate the protective effect of recombinant Grx1 against oxidative stress, we constructed the pET-30a (+)/Grx1 recombinant plasmid and performed soluble expression and purification of the recombinant Grx1. In vitro experiments, including ABTS and DPPH radical scavenging assays, showed that recombinant Grx1 has significant antioxidant activity. Reactive oxygen species detection revealed that the levels of reactive oxygen species in the Grx1 treatment group decreased by 33.01 % compared to the H2O2 group. Flow cytometry analyses indicated that the number of apoptotic cells in the Grx1 treatment group decreased by 23.51 % relative to the H2O2 group. Additionally, qRT-PCR analysis showed that Grx1 significantly reduced the expression levels of genes such as IL-1β, TNF-α, IL-6, and caspase-3 in PC12 cells. In vivo, recombinant Grx1 was utilized to treat cerebral ischemia-reperfusion injury (CIRI). Histological staining revealed that recombinant Grx1 significantly mitigated hippocampal tissue damage. Western blotting analysis demonstrated that Grx1 can reduce neuronal apoptosis following CIRI by decreasing Bax expression while increasing Bcl-2 expression. Furthermore, Grx1 was shown to modulate the HO-1/Nrf2 signaling pathway by elevating the expression of Nrf2 and HO-1. In summary, this study successfully overexpressed biologically active Grx1 in E. coli, and confirms that recombinant Grx1 exhibits remarkable antioxidant activity in both in vitro and in vivo experiments, effectively alleviating oxidative stress damage associated with ischemic stroke.

Modes of Mitochondrial Reactive Oxygen Species Production in Inflammation

Background: Inflammation is one of the most important pathways in innate immunity and its relationship with redox biology is becoming increasingly clear in the last decades. However, the specific redox modes and pathways by which inflammation is produced are not yet well defined. Significance: In this review, we provide a general explanation of the reactive oxygen species (ROS) production and quenching modes occurring in mammalian mitochondria, as well as a summary of the most recent advances in mitochondrial redox biology and bioenergetics regarding sodium (Na+) homeostasis. In addition, we provide a collection of examples in which several inflammatory pathways have been associated with specific modes of either mitochondrial ROS production or quenching. Innovation: The role of Na+ in mitochondrial biology is being developed. Since its discovery as a second messenger, the research of its role in the immune system has emerged. Now, the role of Na+ in mitochondrial bioenergetics has recently been identified, which owns unprecedented applications. The potential implication of Na+ in inflammatory mechanisms grows as its role does not only cover ROS production and respiration but also the control through the management of mitochondrial membrane potential. Future directions: Na+ is becoming relevant for mitochondrial biology. Thus, processes regarding mitochondrial bioenergetics, redox state, or metabolism may probably need to include the study of Na+ in their road map. Some of these pathways are involved in inflammation and more are possibly to come. This review is expected to serve as a bridge between both fields. Antioxid. Redox Signal. 00, 000-000.

Genome-wide analysis of alternative splicing differences in hepatic ischemia reperfusion injury

Alternative splicing (AS) contributes to transcript and protein diversity, affecting their structure and function. However, the specific transcriptional regulatory mechanisms underlying AS in the context of hepatic ischemia reperfusion (IR) injury in mice have not been extensively characterized. In this study, we investigated differentially alternatively spliced (DAS) genes and differentially expressed transcripts (DETs) in a mouse model of hepatic IR injury using the high throughput RNA sequencing (RNA-seq) analysis and replicate multivariate analysis of transcript splicing (rMATS) analysis. We further conducted Gene ontology (GO) term enrichment, the Kyoto Encyclopedia of Genes and Genomes (KEGG) database and the protein-protein interaction (PPI) network. A total of 898 DAS genes (p ≤ 0.05) were screened out in the hepatic IR group compared to the sham group, while functional enrichment analysis revealed that DETs and DAS genes were significantly associated with the ATP-dependent chromain, splicesome and metabolic pathways. The expression level of the DAS genes: Gabpb2, Smg1, Tnrc6c, Mettl17, Smpd4, Kcnt2, D16Ertd472e, Rab3gap2, Echdc2 and Ssx2ip were verified by RT-PCR and qRT-PCR. Our findings provide a comprehensive genome-wide view of AS events in hepatic IR injury in mice, enhancing our understanding of AS dynamics and the molecular mechanisms governing alternative pre-mRNA splicing.

Pericyte loss via glutaredoxin2 downregulation aggravates diabetes-induced microvascular dysfunction

Diabetic retinopathy (DR) is the leading cause of vision loss and blindness among working-age adults. Pericyte loss is an early pathological feature of DR. Under hyperglycemic conditions, reactive oxygen species (ROS) production increases, leading to oxidative stress and subsequent mitochondrial dysfunction and apoptosis. Dysfunctional pericyte can cause retinal vascular leakage, obliteration, and neovascularization. Glutaredoxin 2 (Grx2) is a mitochondrial glutathione-dependent oxidoreductase which protects cells against oxidative insults by safeguarding mitochondrial function. Whether Grx2 plays a protective role in diabetes-induced microvascular dysfunction remains unclear. Our findings revealed that diabetes-related stress reduced Grx2 expression in pericytes, but not in endothelial cells. Grx2 knock-in ameliorated diabetes-induced microvascular dysfunction in vivo DR models. Decreased Grx2 expression led to significant pericyte apoptosis, and pericyte dysfunction, namely reduced pericyte recruitment towards endothelial cells and increased endothelial cell permeability. Conversely, upregulating Grx2 reversed these effects. Furthermore, Grx2 regulated pericyte apoptosis by modulating complex I activity, which is crucial for pericyte mitochondrial function. Overall, our study uncovered a novel mechanism whereby high glucose inhibited Grx2 expression in vivo and in vitro. Grx2 downregulation exacerbated pericyte apoptosis, pericyte dysfunction, and retinal vascular dysfunction by inactivating complex I and mediating mitochondrial dysfunction in pericytes.

The role of serine/threonine protein kinases in cardiovascular disease and potential therapeutic methods

Protein phosphorylation is an important link in a variety of signaling pathways, and most of the important life processes in cells involve protein phosphorylation. Based on the amino acid residues of phosphorylated proteins, protein kinases can be categorized into the following families: serine/threonine protein kinases, tyrosine-specific protein kinases, histidine-specific protein kinases, tryptophan kinases, and aspartate/glutamyl protein kinases. Of all the protein kinases, most are serine/threonine kinases, where serine/threonine protein kinases are protein kinases that catalyze the phosphorylation of serine or threonine residues on target proteins using ATP as a phosphate donor. The current socially accepted classification of serine/threonine kinases is to divide them into seven major groups: protein kinase A, G, C (AGC), CMGC, Calmodulin-dependent protein kinase (CAMK), Casein kinase (CK1), STE, Tyrosine kinase (TKL) and others. After decades of research, a preliminary understanding of the specific classification and respective functions of serine/threonine kinases has entered a new period of exploration. In this paper, we review the literature of the previous years and introduce the specific signaling pathways and related therapeutic modalities played by each of the small protein kinases in the serine/threonine protein kinase family, respectively, in some common cardiovascular system diseases such as heart failure, myocardial infarction, ischemia-reperfusion injury, and diabetic cardiomyopathy. To a certain extent, the current research results, including molecular mechanisms and therapeutic methods, are fully summarized and a systematic report is made for the prevention and treatment of cardiovascular diseases in the future.

Activation of the Nrf2/HO-1 axis by glutaredoxin 2 overexpression antagonizes vascular endothelial cell oxidative injury and inflammation under LPS exposure

Atherosclerosis constitutes a proverbial pathogenic mechanism for cardio-cerebrovascular disease that accounts for the most common cause of disability and morbidity for human health worldwide. Endothelial dysfunction and inflammation are the key contributors to the progression of atherosclerosis. Glutaredoxin 2 (GLRX2) is abundantly existed in various tissues and possesses a range of pleiotropic efficacy including anti-oxidative and anti-inflammatory responses. However, its role in atherosclerosis is still undefined. Here, down-regulation of GLRX2 was validated in lipopolysaccha (LPS)-induced vascular endothelial cells (HUVECs). Moreover, elevation of GLRX2 reversed the inhibition of cell viability in LPS-treated HUVECs and decreased LPS-induced increases in cell apoptosis and caspase-3 activity. Additionally, enhancement of GLRX2 expression antagonized oxidative stress in HUVECs under LPS exposure by inhibiting ROS, lactate dehydrogenase and malondialdehyde production and increased activity of anti-oxidative stress superoxide dismutase. Notably, GLRX2 abrogated LPS-evoked transcripts and releases of pro-inflammatory cytokine (TNF-α, IL-6, and IL-1β), chemokine MCP-1 and adhesion molecule ICAM-1 expression. Furthermore, the activation of Nrf2/HO-1 signaling was demonstrated in LPS-stimulated HUVECs. Importantly, blockage of the Nrf2 pathway counteracted the protective roles of GLRX2 in LPS-triggered endothelial cell injury, oxidative stress and inflammatory response. Thus, these data reveal that GLRX2 may alleviate the progression of atherosclerosis by regulating vascular endothelial dysfunction and inflammation via the activation of the Nrf2 signaling, supporting a promising therapeutic approach for atherosclerosis and its complications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-023-00606-x.

Glutaredoxin 2 Protein (Grx2) as an Independent Prognostic Factor Associated with the Survival of Colon Adenocarcinoma Patients

Glutaredoxin 2 (Grx2; Glrx2) is a glutathione-dependent oxidoreductase located in mitochondria, which is central to the regulation of glutathione homeostasis and mitochondrial redox, and plays a crucial role in highly metabolic tissues. In response to mitochondrial redox signals and oxidative stress, Grx2 can catalyze the oxidation and S-glutathionylation of membrane-bound thiol proteins in mitochondria. Therefore, it can have a significant impact on cancer development. To investigate this further, we performed an immunohistochemical analysis of Grx2 protein expression in colon adenocarcinoma samples collected from patients with primary colon adenocarcinoma (stage I and II) and patients with metastasis to regional lymph nodes (stage III). The results of our study revealed a significant relationship between the immunohistochemical expression of Grx2 and tumor histological grade, depth of invasion, regional lymph node involvement, angioinvasion, staging, and PCNA immunohistochemical expression. It was found that 87% of patients with stage I had high levels of Grx2 expression. In contrast, only 33% of patients with stage II and 1% of patients with stage III had high levels of Grx2 expression. Moreover, the multivariate analysis revealed that the immunohistochemical expression of Grx2 protein apart from the grade of tumor differentiation was an independent prognostic factors for the survival of patients with colon adenocarcinoma. Studies analyzing Grx2 levels in patients' blood confirmed that the highest levels of serum Grx2 protein was also found in stage I patients, which was reflected in the survival curves. A higher level of Grx2 in the serum has been associated with a more favorable outcome. These results were supported by in vitro analysis conducted on colorectal cancer cell lines that corresponded to stages I, II, and III of colorectal cancer, using qRT-PCR and Western Blot.

Glutaredoxin 2 protects lens epithelial cells from epithelial-mesenchymal transition by suppressing mitochondrial oxidative stress-related upregulation of integrin-linked kinase

Glutaredoxin 2 (Grx2), a mitochondrial glutathione-dependent oxidoreductase, is crucial for maintaining redox homeostasis and cellular functions in the lens. The oxidative stress-induced epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) is related to posterior capsule opacification. In this study, we investigated the effects of Grx2 on oxidative stress-induced EMT in LECs during posterior capsule opacification. We found that Grx2 expression was substantially decreased during the EMT of LECs and in a mouse model of cataract surgery. Deletion of Grx2 aggravated the generation of reactive oxygen species, including those that are mitochondria-derived, and promoted the proliferation and EMT of the LECs. This was reversed by Grx2 overexpression. In vivo, proteomic liquid chromatography-mass spectrometry analysis showed that integrin-linked kinase (ILK) was significantly upregulated in the lens posterior capsule of a Grx2 knockout (KO) mouse model. Compared with that of the wild-type group, the expression of ILK and EMT markers was increased in the Grx2 KO group which was reversed in the Grx2 knock-in group. Inhibition of ILK partially blocked Grx2 knockdown-induced EMT and prevented the increased phosphorylation of Akt and GSK-3β and the nuclear translocation of β-catenin in the Grx2 KO group. Finally, inhibition of the Wnt/β-catenin pathway partially blocked the Grx2 knockdown-induced EMT. In conclusion, we demonstrated that Grx2 protects LECs from oxidative stress-related EMT by regulating the ILK/Akt/GSK-3β axis.

Glutaredoxin 2 in the mud crab Scylla paramamosain: Identification and functional characterization under hypoxia and pathogen challenge

Glutaredoxin (Grx) is a glutathione-dependent oxidoreductase that plays a key role in antioxidant defense. In this study, a novel Grx2 gene (SpGrx2) was identified from the mud crab Scylla paramamosain, which consists of a 196 bp 5' untranslated region, a 357 bp open reading frame, and a 964 bp 3' untranslated region. The putative SpGrx2 protein has a typical single Grx domain with the active center sequence C-P-Y-C. The expression analysis revealed that the SpGrx2 mRNA was most abundant in the gill, followed by the stomach and hemocytes. Both mud crab dicistrovirus-1 and Vibrioparahaemolyticus infection as well as hypoxia could differentially induce the expression of SpGrx2. Furthermore, silencing SpGrx2 in vivo affected the expression of a series of antioxidant-related genes after hypoxia treatment. Additionally, SpGrx2 overexpression significantly increased the total antioxidant capacity of Drosophila Schneider 2 cells after hypoxia, resulting in a reduction of reactive oxygen species and malondialdehyde content. The subcellular localization results indicated that SpGrx2 was localized in both the cytoplasm and the nucleus of Drosophila Schneider 2 cells. These results indicate that SpGrx2 plays a crucial role as an antioxidant enzyme in the defense system of mud crabs against hypoxia and pathogen challenge.

Nrf2 attenuates methamphetamine-induced myocardial injury by regulating oxidative stress and apoptosis in mice

OBJECTIVES

Methamphetamine (MA) abuse is a serious social problem worldwide. Cardiovascular complications were the second leading cause of death among MA abusers. We aimed to clarify the effects of MA on myocardial injury, oxidative stress, and apoptosis in myocardial cells and to explore the potential mechanism of nuclear factor-erythroid factor 2-related factor 2 (Nrf2) in MA-induced oxidative stress and apoptosis.

METHODS

An acute cardiac toxicity model of MA was established by intraperitoneal injection of MA (2 mg/kg) for 5 days. Nrf2 activation (by sulforaphane (SFN) 1 h before MA injection) and Nrf2 gene knockout were performed to explore the regulatory effects of Nrf2 on cardiac toxicity.

RESULTS

The protein expressions of Nrf2 (p < .001) and heme oxygenase-1 (HO-1) were increased (p < .01), suggesting that MA activated the Nrf2/HO-1 pathway. In the MA group, cardiac injury score (p < .001) and cardiac troponin I (cTnI) protein expression increased (p < .01). Malondialdehyde (MDA) content increased (p < .001), superoxide dismutase (SOD) activity decreased (p < .05). Protein expressions of Caspase-3 (p < .001) and Bax (p < .001) increased, and Bcl-2 decreased (p < .001) as well. These changes were reversed by activation of Nrf2 but became more pronounced after Nrf2 knockout, suggested that the activation and knockout of Nrf2 attenuated and aggravated MA-induced myocardial injury, oxidative stress and apoptosis in myocardial cells, respectively.

CONCLUSIONS

MA administration induced myocardial injury, oxidative stress, and apoptosis in mice. Nrf2 attenuated MA-induced myocardial injury by regulating oxidative stress and apoptosis, thus playing a protective role.

Hypoxia Affects the Antioxidant Activity of Glutaredoxin 3 in Scylla paramamosain through Hypoxia Response Elements

Hypoxia is a major environmental stressor that can damage the oxidation metabolism of crustaceans. Glutaredoxin (Grx) is a key member of the thioredoxin superfamily and plays an important role in the host's defense against oxidative stress. At present, the role of Grx in response to hypoxia in crustaceans remains unclear. In this study, the full-length cDNA of Grx3 (SpGrx3) was obtained from the mud crab Scylla paramamosain, which contains a 129-bp 5' untranslated region, a 981-bp open reading frame, and a 1,183-bp 3' untranslated region. The putative SpGrx3 protein contains an N-terminal thioredoxin domain and two C-terminal Grx domains. SpGrx3 was expressed in all tissues examined, with the highest expression in the anterior gills. After hypoxia, SpGrx3 expression was significantly up-regulated in the anterior gills of mud crabs. The expression of Grx2 and glutathione S-transferases was decreased, while the expression of glutathione peroxidases was increased following hypoxia when SpGrx3 was silenced in vivo. In addition, the total antioxidant capacity of SpGrx3-interfered mud crabs was significantly decreased, and the malondialdehyde content was significantly increased during hypoxia. The subcellular localization data indicated that SpGrx3 was predominantly localized in the nucleus when expressed in Drosophila Schneider 2 (S2) cells. Moreover, overexpression of SpGrx3 reduced the content of reactive oxygen species in S2 cells during hypoxia. To further investigate the transactivation mechanism of SpGrx3 during hypoxia, the promoter region of the SpGrx3 was obtained by Genome Walking and three hypoxia response elements (HREs) were predicted. Dual-luciferase reporter assay results demonstrated that SpGrx3 was likely involved in the hypoxia-inducible factor-1 (HIF-1) pathway during hypoxia, which could be mediated through HREs. The results indicated that SpGrx3 is involved in regulating the antioxidant system of mud crabs and plays a critical role in the response to hypoxia.

Elevated antioxidant defence in the brain of deep-diving pinnipeds

While foraging, marine mammals undertake repetitive diving bouts. When the animal surfaces, reperfusion makes oxygen readily available for the electron transport chain, which leads to increased production of reactive oxygen species and risk of oxidative damage. In blood and several tissues, such as heart, lung, muscle and kidney, marine mammals generally exhibit an elevated antioxidant defence. However, the brain, whose functional integrity is critical to survival, has received little attention. We previously observed an enhanced expression of several antioxidant genes in cortical neurons of hooded seals (Cystophora cristata). Here, we studied antioxidant gene expression and enzymatic activity in the visual cortex, cerebellum and hippocampus of harp seals (Pagophilus groenlandicus) and hooded seals. Moreover, we tested several genes for positive selection. We found that antioxidants in the first line of defence, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione (GSH) were constitutively enhanced in the seal brain compared to mice (Mus musculus), whereas the glutaredoxin and thioredoxin systems were not. Possibly, the activity of the latter systems is stress-induced rather than constitutively elevated. Further, some, but not all members, of the glutathione-s-transferase (GST) family appear more highly expressed. We found no signatures of positive selection, indicating that sequence and function of the studied antioxidants are conserved in pinnipeds.

α-Cyperone Protects Cardiomyocytes against Oxygen-Glucose Deprivation-Induced Inflammation and Oxidative Stress by Akt/FOXO3a/NF-κB Pathway

Objective. This study is aimed at investigating the mechanism of α-cyperone in oxygen and glucose deprivation- (OGD-) induced myocardial injury. Methods. Cardiomyocytes were exposed to OGD and then treated with α-cyperone. The cell counting kit-8 (CCK-8) assay and flow cytometry were performed to determine cell proliferation and apoptosis, respectively. The expression of inflammatory factors was monitored by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The profiles of apoptosis-related proteins, inflammatory proteins, and the Akt/FOXO3a/NF-κB pathway were determined by western blot. The phosphorylation of Akt, FOXO3a, and NF-κB was determined by immunofluorescence assay. The superoxide dismutase (SOD) activity and the malondialdehyde (MDA) content were gauged by the colorimetric method, and the reactive oxygen species (ROS) content was measured. Results. α-Cyperone hindered OGD-induced inflammation, oxidative stress, and apoptosis in cardiomyocytes. OGD activated the FOXO3a/NF-κB pathway and hampered the Akt phosphorylation. α-cyperone reversed OGD-mediated FOXO3a/NF-κB pathway activation. Treatment with MK-2206 abated the protective effect of α-cyperone against OGD-induced myocardial injury. The addition of α-cyperone to cardiomyocytes following Bay11-7082 treatment had no conspicuous effect on the viability and apoptosis. Conclusions. α-Cyperone protected cardiomyocytes against OGD-induced inflammation and oxidative stress via the Akt/FOXO3a/NF-κB axis.

Naringenin ameliorates myocardial injury in STZ-induced diabetic mice by reducing oxidative stress, inflammation and apoptosis via regulating the Nrf2 and NF-κB signaling pathways

Diabetes-induced myocardial damage leads to diabetic cardiomyopathy and is closely associated with the generation of oxidative stress and inflammation. Naringenin (NG) exhibits antioxidant and anti-inflammatory effects. However, whether NG has cardioprotective effects against diabetic cardiomyopathy by regulating oxidative stress and inflammation remains unknown. This study investigated the effect of NG on diabetic cardiomyopathy based on an analysis of streptozotocin (STZ)-induced type 1 diabetic mice. The results indicated that NG reduced cardiac fibrosis and cardiomyocyte apoptosis in this diabetic model, accompanied by reduced blood glucose. NG inhibited pro-inflammatory cytokines, the level of reactive oxygen species and the expression of nuclear factor kappa-B (NF-κB), whereas the expression of antioxidant enzymes and nuclear factor erythroid 2-related factor 2 (Nrf2) were greatly enhanced by NG. Furthermore, in high glucose-treated H9C2 myocardial cells, NG effectively reduced cell apoptosis by inhibiting the formation of reactive oxygen species and pro-inflammatory cytokines. NG's antioxidant and anti-inflammatory activities were mechanistically associated with NF-κB inhibition and Nrf2 activation in animal and cell experiments. Data analysis showed that NG could regulate Nrf2 and NF-κB pathways to protect against diabetes-induced myocardial damage by reducing oxidative stress and inhibiting inflammation.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

Biochanin A protects SH-SY5Y cells against isoflurane-induced neurotoxicity by suppressing oxidative stress and apoptosis

Biochanin A (BCA) is a natural organic O-methylated isoflavone with a variety of pharmacological effects, and has been reported to have neuroprotective properties. Here, we explored whether BCA protects neurocytes against isoflurane-induced neurotoxicity and investigated the underlying mechanism. Cell viability was tested by cell counting kit-8 and lactate dehydrogenase release assays. Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and caspase-3/7 activity assays. Superoxide dismutase (SOD) and catalase (CAT) activities and levels of glutathione (GSH) and malondialdehyde (MDA) were measured to assess oxidative stress. Expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase (NQO1) was determined by western blotting. Treatment with BCA significantly attenuated the reduction of cell viability induced by isoflurane in SH-SY5Y cells. In addition, BCA treatment reversed isoflurane-induced SOD and CAT activity reduction, GSH level decline and MDA level increase. Isoflurane-induced apoptosis was also attenuated by treatment with BCA. The increase in nuclear Nrf2, HO-1 and NQO1 expression induced by isoflurane was amplified by treatment with BCA. These inhibitory effects of BCA on isoflurane-induced oxidative stress, viability reduction and cell apoptosis were attenuated in Nrf2 knockdown SH-SY5Y cells. Our findings indicate that BCA protects SH-SY5Y cells against isoflurane-induced neurotoxicity via inducing the Nrf2/ARE pathway.

Up-regulation of CTRP12 ameliorates hypoxia/re-oxygenation-induced cardiomyocyte injury by inhibiting apoptosis, oxidative stress, and inflammation via the enhancement of Nrf2 signaling

C1q/TNF-related protein 12 (CTRP12) has been reported to play a key role in coronary artery disease. However, whether CTRP12 plays a role in the regulation of myocardial ischemia-reperfusion injury is not fully understood. The goals of this work were to assess the possible relationship between CTRP12 and myocardial ischemia-reperfusion injury. Here, we exposed cardiomyocytes to hypoxia/re-oxygenation (H/R) to establish an in vitro cardiomyocyte injury model of myocardial ischemia-reperfusion injury. Our results showed that H/R treatment resulted in a decrease in CTRP12 expression in cardiomyocytes. The up-regulation of CTRP12 ameliorated H/R-induced cardiomyocyte injury via the down-regulation of apoptosis, oxidative stress, and inflammation. In contrast, the knockdown of CTRP12 enhanced cardiomyocyte sensitivity to H/R-induced cardiomyocyte injury. Further investigation showed that CTRP12 enhanced the levels of nuclear Nrf2 and increased the expression of Nrf2 target genes in cardiomyocytes exposed to H/R. However, the inhibition of Nrf2 markedly diminished CTRP12-overexpression-mediated cardioprotective effects against H/R injury. Overall, these data indicate that CTRP12 protects against H/R-induced cardiomyocyte injury by inhibiting apoptosis, oxidative stress, and inflammation via the enhancement of Nrf2 signaling. This work suggests a potential role of CTRP12 in myocardial ischemia-reperfusion injury and proposes it as an attractive target for cardioprotection.