Nebulized Dexmedetomidine Alleviates Oxidative Stress in Ventilator-induced Lung Injury via Keap1-Nrf2-ARE Pathway.

This study aimed to explore the underlying mechanism of nebulized dexmedetomidine (DEX) in ameliorating ventilator-induced lung injury (VILI)-induced oxidative stress in rats. Forty 7 to 8-week-old Sprague-Dawley rats at the specific pathogen-free level were randomized into the control group, model group, nebulized dexmedetomidine (WH-YM) group, and dexmedetomidine intravenous infusion (JM-YM) group, each containing 10 rats. Except for the control group, rats in the other groups underwent mechanical ventilation (tidal volume,  40 mL/kg; respiratory rate, 70 breaths per minute; inspiratory-to-expiratory ratio, 1:2; fraction of inspired oxygen, 21%; positive end-expiratory pressure, 0 cmH2O). Nebulized DEX (6.3 µg/kg), and isodose intravenous DEX  were given to rats of WH-YM and JM-YM groups prior to ventilation. Post 4-hour ventilation, rats were euthanized. Lung tissue wet-to-dry weight ratio, H&E staining for assessing diffuse alveolar damage (DAD), and expression levels of Nrf2 and Keap1 detected by qRT-PCR and Western blot were compared. Inflammatory markers TNF-α, IL-2, and IL-6, and oxidative stress indices malondialdehyde (MDA) and superoxide dismutase (SOD), were quantified in lung tissues and serum samples using commercial kits.  Rats in the WH-YM and JM-YM groups demonstrated significant ameliorations in the wet-to-dry weight ratio and DAD score, decreased Keap1, TNF-α, IL-2, and IL-6 levels in lung tissues and serum samples, but increased Nrf2 and SOD level than those of controls. These changes were more pronounced in the WH-YM group than in the JM-YM group. DEX effectively alleviates VILI-induced oxidative stress and inflammation via the Keap1-Nrf2-ARE signaling pathway., especially in the nebulized administration.

Nrf2/Keap1/ARE regulation by plant secondary metabolites: a new horizon in brain tumor management.

Brain cancer is regarded as one of the most life-threatening forms of cancer worldwide. Oxidative stress acts to derange normal brain homeostasis, thus is involved in carcinogenesis in brain. The Nrf2/Keap1/ARE pathway is an important signaling cascade responsible for the maintenance of redox homeostasis, and regulation of anti-inflammatory and anticancer activities by multiple downstream pathways. Interestingly, Nrf2 plays a somewhat, contradictory role in cancers, including brain cancer. Nrf2 has traditionally been regarded as a tumor suppressor since its cytoprotective functions are considered to be the principle cellular defense mechanism against exogenous and endogenous insults, such as xenobiotics and oxidative stress. However, hyperactivation of the Nrf2 pathway supports the survival of normal as well as malignant cells, protecting them against oxidative stress, and therapeutic agents. Plants possess a pool of secondary metabolites with potential chemotherapeutic/chemopreventive actions. Modulation of Nrf2/ARE and downstream activities in a Keap1-dependant manner, with the aid of plant-derived secondary metabolites exhibits promise in the management of brain tumors. Current article highlights the effects of Nrf2/Keap1/ARE cascade on brain tumors, and the potential role of secondary metabolites regarding the management of the same.

Lutein protects senescent ciliary muscle against oxidative stress through the Keap1/Nrf2/ARE pathway.

BACKGROUND: Aging-induced decline in ciliary muscle function is an important factor in visual accommodative deficits in elderly adults. With this study, we provide an innovative investigation of the interaction between ciliary muscle aging and oxidative stress. METHODS: Tricolor guinea pigs were used for the experiments in vivo and primary guinea pig ciliary smooth muscle cells were used for the experiments in vitro. RESULTS: We enriched for genes associated with muscle-aging-lutein relationship using bioinformatics, including Nuclear factor-erythroid 2-related factor-2 (Nrf2), Glutathione Peroxidase (GPx) gene family, Superoxide Dismutase (SOD) gene family, NAD(P)H: Quinone Oxidoreductase 1 (NQO1) and Heme Oxygenase-1 (HO-1). After gavage to aged guinea pigs, lutein reduced Reactive Oxygen Species (ROS) and P21 levels in senescent ciliary muscle; lutein decreased refractive error and restored accommodation of the eye. In addition, lutein increased GPx, SOD, and Catalase (CAT) levels in serum; lutein increased GPx and CAT levels in ciliary bodies. Lutein regulated the expression of proteins such as Nrf2, Kelch-like ECH-associated protein 1 (Keap1), and downstream proteins in senescent ciliary bodies. Similarly, guinea pig ciliary muscle cell senescence was associated with oxidative stress. In vitro, 100 µM lutein reversed the damage caused by 800 µM H2O2; it reduced Senescence-Associated ß-galactosidase (SA-ß-Gal) and ROS activites, cell apoptosis and cell migration. Also, lutein increased the expression of smooth muscle contractile proteins. Lutein also increased the expression of Nrf2, GPx2, NQO1 and HO-1, decreased the expression of Keap1. A reduction in Nrf2 activity led to a reduction in the ability of lutein to activate antioxidant enzymes in the cells, thus reducing its inhibitory effect on cell senescence. CONCLUSION: lutein improved resistance to oxidative stress in senescent ciliary muscle in vivo and in vitro by regulating the Keap1/Nrf2/Antioxidant Response Element pathway. We have innovatively demonstrated the molecular pharmacological mechanism by which lutein reverse age-related ciliary muscle systolic and diastolic deficits.

Alleviating Effect of Lipid Phytochemicals in Seed Oil (Brassica napus L.) on Oxidative Stress Injury Induced by H2O2 in HepG2 Cells via Keap1/Nrf2/ARE Signaling Pathway.

α-tocopherol (α-T), ß-sitosterol (ß-S), canolol (CA), and sinapic acid (SA) are the four main endogenous lipid phytochemicals (LP) found in Brassica napus L. seed oil, which possess the bioactivity to prevent the risk of several chronic diseases via antioxidant-associated mechanisms. Discovering the enhancer effects or synergies between LP is valuable for resisting oxidative stress and improving health benefits. The objectives of this study were to identify a potentially efficacious LP combination by central composite design (CCD) and cellular antioxidant activity (CAA) and to investigate its protective effect and potential mechanisms against H2O2-induced oxidative damage in HepG2 cells. Our results indicated that the optimal concentration of LP combination was α-T 10 µM, ß-S 20 µM, SA 125 µM, and CA 125 µM, respectively, and its CAA value at the optimal condition was 10.782 µmol QE/100 g. At this concentration, LP combination exerted a greater amelioration effect on H2O2-induced HepG2 cell injury than either antioxidant (tea polyphenols or magnolol) alone. LP combination could reduce the cell apoptosis rate induced by H2O2, lowered to 10.06%, and could alleviate the degree of oxidative damage to cells (ROS↓), lipids (MDA↓), proteins (PC↓), and DNA (8-OHdG↓). Additionally, LP combination enhanced the antioxidant enzyme activities (SOD, CAT, GPX, and HO-1), as well as the T-AOC, and increased the GSH level in HepG2 cells. Furthermore, LP combination markedly upregulated the expression of Nrf2 and its associated antioxidant proteins. It also increased the expression levels of Nrf2 downstream antioxidant target gene (HO-1, SOD-1, MnSOD, CAT, GPX-1, and GPX-4) and downregulated the mRNA expression levels of Keap1. The oxidative-stress-induced formation of the Keap1/Nrf2 complex in the cytoplasm was significantly blocked by LP treatment. These results indicate that LP combination protected HepG2 cells from oxidative stress through a mechanism involving the activation of the Keap1/Nrf2/ARE signaling pathways.

Ocotillol Derivatives Mitigate Retinal Ischemia-Reperfusion Injury by Regulating the Keap1/Nrf2/ARE Signaling Pathway.

Retinal ischemia-reperfusion (RIR) injury can lead to various retinal diseases. Oxidative stress is considered an important pathological event in RIR injury. Here, we designed and synthesized 34 ocotillol derivatives, then examined their antioxidant and anti-inflammatory capacities; we found that compounds 7 (C24-R) and 8 (C24-S) were most active. To enhance their water solubility, sustained release, and biocompatibility, compounds 7 and 8 were encapsulated into liposomes for in vivo activity and mechanistic studies. In vivo studies indicated that compounds 7 and 8 protected normal retinal structure and physiological function after RIR injury, reversed damage to retinal ganglion cells, and the S-configuration exhibited significantly stronger activity compared with the R-configuration. Mechanistic studies showed that compound 8 exerted a therapeutic effect on RIR injury by activating the Keap1/Nrf2/ARE signaling pathway; compound 7 did not influence this pathway. We also demonstrated that differential isomerization at the C-24 position influenced protection against RIR injury.

Exploring the protective potential of NRF2 overexpressed neural extracellular vesicles against cisplatin-induced neurotoxicity via NRF2/ARE pathway.

Neurotoxicity is characterized by the accumulation of harmful chemicals such as heavy metals and drugs in neural tissue, resulting in subsequent neuronal death. Among chemicals platinum-based cancer drugs are frequently used due to their antineoplastic effects, but this drug is also known to cause a wide range of toxicities, such as neurotoxicity. The nuclear-factor-erythroid 2-related factor-2 (NRF2) is crucial in combating oxidative stress and maintaining cellular homeostasis. This study thoroughly explores the protective effects of extracellular vesicles derived from NRF2 gene overexpressed neural progenitor cells (NEVs) on cisplatin-induced neurotoxicity. Therefore, extracellular vesicles derived from neural progenitor cells were isolated and characterized. The Cisplatin neurotoxicity dose was 75 µM in mature, post-mitotic neurons. 1.25 µM of tert-butyl hydroquinone that induces NRF2/ARE pathway was used as the positive control. The effects of extracellular vesicles (EVs) were investigated using functional and molecular assays such as PCR and protein-based assays. Here, we observed that NEVs dose-dependently protected post-mitotic neuron cells in response to cisplatin. The study also examined whether the effect was EV-induced by limiting EV biogenesis. The molecular basis of preventive treatment was established. When pre-administered, 1×108 particles/ml of NEVs maintained antioxidant and detoxifying gene and protein expression levels similar to control cell levels. Furthermore, NEVs reduced both cellular and mitochondrial ROS levels and preserved mitochondrial membrane potential. In addition, Catalase and SOD levels were found higher in NEV-treated cells compared to cisplatin control. The findings in NRF2-based protection of cisplatin-induced neurotoxicity may provide further evidence for the relationship between EVs and inhibition of neuronal stress through the NRF2/ARE pathway, increasing the understanding of neuroprotective responses and the development of gene-engineered EV therapy options for peripheral neuropathy or other neurodegenerative diseases. This is the first study in the literature to investigate the neutralizing potency of NRF2 overexpressed neural EVs against cisplatin-induced neurotoxicity.

Impaired HBsAg release and antiproliferative/antioxidant cell regulation by HBeAg-negative patient isolates reflects an evolutionary process.

BACKGROUND: The hepatitis B e antigen (HBeAg)-negative infection Phase 3 is characterized by no or minimal signs of hepatic inflammation and the absence of hepatic fibrosis. However, underlying molecular mechanisms leading to this benign phenotype are poorly understood. METHODS: Genotype A, B and D HBeAg-negative patient isolates with precore mutation G1896A from Phase 3 were analysed in comparison with respective HBeAg-positive rescue mutant and HBeAg-positive wild-type reference genomes regarding differences in viral replication, morphogenesis, infectivity and impact on NF-E2-related factor 2 (Nrf2)/antioxidant response element (ARE)-dependent gene expression and cellular kinome. RESULTS: In comparison with reference genomes, the patient isolates are characterized by a lower intra- and extracellular hepatitis B surface antigen (HBsAg)-amount, and HBsAg-retention in the endoplasmic reticulum. Rescue of HBeAg expression increased HBsAg-amount but not its release. Expression of the isolated genomes is associated with a higher Nrf2/ARE-dependent gene expression as compared to reference genomes independent of HBeAg expression. Kinome analyses revealed a decreased activity of receptors involved in regulation of proliferative pathways for all patient isolates compared to the reference genomes. No specific conserved mutations could be found between all genomes from Phase 3. CONCLUSIONS: HBeAg-negative genomes from Phase 3 exhibit distinct molecular characteristics leading to lower HBsAg synthesis and release, enhanced oxidative stress protection and decreased activity of key kinases, triggering an antiproliferative stage, which might contribute to the lower probability of hepatocellular carcinoma. The observed differences cannot be associated with loss of HBeAg or specific mutations common to all analysed isolates, indicating the phenotype of Phase 3 derived genomes to be the result of a multifactorial process likely reflecting a conserved natural selection process.

Rutin alleviates Pb-induced oxidative stress, inflammation and cell death via activating Nrf2/ARE system in SH-SY5Y cells.

Lead (Pb) is harmful to almost all organs, particularly the developmental neural system, and previous studies revealed oxidative stress played an important role in Pb neurotoxicity. Rutin, a type of flavonoid glycoside found in various plants and fruits, is widely used as a dietary supplement due to its antioxidant and anti-inflammatory properties, but whether rutin could protect against Pb neurotoxicity is unclear. In this study, we found rutin treatment significantly alleviated Pb-induced cell death, oxidative stress, and inflammation, resulting in cell survival. Moreover, rutin treatment promoted nuclear factor erythroid 2-related factor 2 (Nrf2) translocation from cytoplasm to nucleus and subsequently activated antioxidant and detoxifying enzymes expression including HO-1. Knocking down Nrf2 by siRNA transfection abolished this protection of rutin against Pb. Overall, rutin could alleviate Pb-induced oxidative stress, inflammation, and cell death by activating the Nrf2/antioxidant response elements (ARE) system.

Icariin alleviates cisplatin-induced premature ovarian failure by inhibiting ferroptosis through activation of the Nrf2/ARE pathway.

Cisplatin is a widely used chemotherapeutic drug that can induce ovarian damage. Icariin (ICA), a natural antioxidant derived from Epimedium brevicornum Maxim., has been found to protect against organ injury. The aim of the present study was to investigate whether ICA can exert an ovarian-protective effect on cisplatin induced premature ovarian failure (POF) and the underlying mechanism involved. The preventive effect of ICA was evaluated using body weight, the oestrous cycle, ovarian histological analysis, and follicle counting. ICA treatment increased body weight, ovarian weight, and the number of follicles and improved the oestrous cycle in POF mice. ICA reduced cisplatin-induced oxidative damage and upregulated the protein expression levels of Nrf2, GPX4 and HO-1. Moreover, ICA reduced the expression levels of Bax and γH2AX and inhibited ovarian apoptosis. In addition, ICA activated the Nrf2 pathway in vitro and reversed changes in the viability of cisplatin-induced KGN cells, reactive oxygen species (ROS) levels, lipid peroxidation, and apoptosis, and these effects were abrogated when Nrf2 was knocked down or inhibited. Molecular docking confirmed that ICA promotes the release of Nrf2 by competing with Nrf2 for binding to Keap1. The inhibitory effects of ICA on cisplatin-induced oxidative stress, ferroptosis, and apoptosis may be mediated by its modulatory effects on the Nrf2 pathway, providing a novel perspective on the potential mechanisms by which ICA prevents POF.

Chlorogenic Acid Alleviates High Glucose-induced HK-2 Cell Oxidative Damage through Activation of KEAP1/NRF2/ARE Signaling Pathway.

OBJECTIVE: To investigate the alleviating effect of chlorogenic acid (CGA) on oxidative damage in high glucose (HG)-induced HK-2 cells and to explore its potential mechanisms. METHODS: We cultured the human proximal tubular cell line HK-2 and divided them into the control group and different concentrations of CGA groups (0, 5, 10, 25, 50, 100, 200 µM). The trypan blue dye test was used to detect CGA's potential cytotoxicity on HK-2 cells. Then, we treated HK-2 with HG and CGA; the Cell Counting Kit-8 (CCK-8) method was used to detect the cell viability of HK-2 cells in each group. Flow cytometry was employed to measure the apoptosis rate of cells. Western blot was performed to detect the expression of apoptosis proteins B-cell lymphoma-2 (BCL-2), BCL-2-associated X protein (BAX), cysteinyl aspartate specific proteinase (CASPASE)-9, and CASPASE-3. In addition, enzymatic activities, including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and lipid peroxide (LPO), were measured with the corresponding detection kits. 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) assay and flow cytometry were performed to detect reactive oxygen species (ROS) production. Western blot analysis and Reverse Transcription-Polymerase Chain Reaction (RT-PCR) were conducted to evaluate protein and mRNA expressions of the Kelch-like ECH-associated protein-1 (KEAP1)/Nuclear factor erythroid 2-related factor 2 (NRF2)/Antioxidant Response Elements (ARE) signaling pathway. RESULTS: The outcomes showed that, in a dose-dependent way, CGA dramatically increased the vitality of HK-2 induced by HG. Furthermore, CGA significantly reduced the HG-stimulated HK-2 cell apoptosis, which may be linked to the promotion of BCL-2 and the suppression of BAX, cleaved-CASPASE-3, and cleaved-CASPASE-9 expression. In HK-2 cells, CGA reduced the formation of ROS generated by HG levels and markedly boosted the activity of the antioxidant enzymes SOD, GSH-Px, and CAT. Furthermore, compared with the HG group, CGA significantly raised NRF2 nuclear expression and downregulated NRF2 cytosolic expression and increased the mRNA expression of NRF2 and its target genes, heme oxygenase-1 (HO-1), KEAP1, and NAD(P)H dehydrogenase quinone 1 (NQO1). CONCLUSION: These results show that CGA might be useful in managing oxidative damage in HG-induced HK-2 cells.

Saikosaponin A Ameliorates Metabolic Inflammation and Intestinal Barrier Damage in DIO Mice through the Nrf2/ARE Pathway.

BACKGROUND: Obesity is linked to impaired intestinal barrier function and inflammation. Saikosaponin A (SSA), a triterpene saponin from Bupleurum chinense, has shown beneficial effects on intestinal colitis in mice. However, the mechanisms underlying SSA's protective effects against obesity are not fully understood. OBJECTIVE: To investigate the effects of SSA on body weight, metabolic disturbances, and intestinal health in diet-induced obese (DIO) mice, and to elucidate the potential mechanisms involved. METHODS: In the in vivo study, DIO mice were supplemented with SSA. Body weight, fasting blood glucose, and metabolic parameters were measured. Intestinal barrier function and inflammation were assessed. In the in vitro study, intestinal epithelial cells were treated with palmitic acid and lipopolysaccharide to induce inflammation. SSA was then administered to evaluate its effects on cell barrier integrity and inflammatory responses. The role of the nuclear factor-E2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway was investigated by silencing Nrf2. RESULTS: SSA supplementation significantly (p < 0.05) decreased body weight and fasting blood glucose levels in DIO mice, and markedly improved metabolic disturbances. This treatment also enhanced intestinal barrier function and reduced metabolic inflammation, likely through increased antioxidant capacity of intestinal epithelial cells via activation of the Nrf2/ARE signaling pathway. In vitro, SSA maintained cell barrier integrity and reduced inflammatory responses by activating the Nrf2/ARE signaling pathway, decreasing intracellular reactive oxygen species content, and increasing transepithelial electrical resistance. However, silencing Nrf2 abolished SSA's protective effects. CONCLUSION: SSA enhances the antioxidant capacity of intestinal epithelial cells, maintains intestinal barrier integrity, and reduces intestinal inflammation in DIO mice through the activation of the Nrf2/ARE signaling pathway. These findings offer new insights into the protective role of SSA in obesity and metabolic diseases.

A tandem activity-based sensing and labeling strategy reveals antioxidant response element regulation of labile iron pools.

Iron is an essential element for life owing to its ability to participate in a diverse array of oxidation-reduction reactions. However, misregulation of iron-dependent redox cycling can also produce oxidative stress, contributing to cell growth, proliferation, and death pathways underlying aging, cancer, neurodegeneration, and metabolic diseases. Fluorescent probes that selectively monitor loosely bound Fe(II) ions, termed the labile iron pool, are potentially powerful tools for studies of this metal nutrient; however, the dynamic spatiotemporal nature and potent fluorescence quenching capacity of these bioavailable metal stores pose challenges for their detection. Here, we report a tandem activity-based sensing and labeling strategy that enables imaging of labile iron pools in live cells through enhancement in cellular retention. Iron green-1 fluoromethyl (IG1-FM) reacts selectively with Fe(II) using an endoperoxide trigger to release a quinone methide dye for subsequent attachment to proximal biological nucleophiles, providing a permanent fluorescent stain at sites of elevated labile iron. IG1-FM imaging reveals that degradation of the major iron storage protein ferritin through ferritinophagy expands the labile iron pool, while activation of nuclear factor-erythroid 2-related factor 2 (NRF2) antioxidant response elements (AREs) depletes it. We further show that lung cancer cells with heightened NRF2 activation, and thus lower basal labile iron, have reduced viability when treated with an iron chelator. By connecting labile iron pools and NRF2-ARE activity to a druggable metal-dependent vulnerability in cancer, this work provides a starting point for broader investigations into the roles of transition metal and antioxidant signaling pathways in health and disease.

Association Between Genes in the Nuclear Factor E2-Related Factor 2 Antioxidative Response Elements Pathway and Cancer-Related Fatigue in Women With Early-Stage Breast Cancer.

OBJECTIVES: To explore genes in the nuclear factor E2-related factor 2 antioxidative response elements (Nrf2-ARE) signaling pathway using a multiomics approach for associations with variability of cancer-related fatigue (CRF) in postmenopausal women with early-stage hormone receptor-positive breast cancer. SAMPLE & SETTING: Postmenopausal women (N = 116) with early-stage hormone receptor-positive breast cancer were recruited from western Pennsylvania. METHODS & VARIABLES: Candidate genes from the Nrf2-ARE pathway were investigated for associations with CRF occurrence and severity. Associations were evaluated using logistic regression for occurrence and linear regression for severity. RESULTS: The rs2706110 TT genotype in NFE2L2 was associated with a 3.5-fold increase in odds of CRF occurrence. The cytosine-phosphate-guanine (CpG) site cg22820568 in PRDX1 was associated with CRF occurrence and severity. IMPLICATIONS FOR NURSING: Biomarkers based on Nrf2-ARE genes may help to identify women at increased risk for more severe CRF and to develop targeted interventions.

Oleanolic acid alleviating ischemia-reperfusion injury in rat severe steatotic liver via KEAP1/NRF2/ARE.

Severe steatosis in donor livers is contraindicated for transplantation due to the high risk of ischemia-reperfusion injury (IRI). Although Ho-1 gene-modified bone marrow mesenchymal stem cells (HO-1/BMMSCs) can mitigate IRI, the role of gut microbiota and metabolites in this protection remains unclear. This study aimed to explore how gut microbiota and metabolites contribute to HO-1/BMMSCs-mediated protection against IRI in severe steatotic livers. Using rat models and cellular models (IAR20 and THLE-2 cells) of steatotic liver IRI, this study revealed that ischemia-reperfusion led to significant liver and intestinal damage, heightened immune responses, impaired liver function, and altered gut microbiota and metabolite profiles in rats with severe steatosis, which were partially reversed by HO-1/BMMSCs transplantation. Integrated microbiome and metabolome analyses identified gut microbial metabolite oleanolic acid as a potential protective agent against IRI. Experimental validation showed that oleanolic acid administration alone alleviated IRI and inhibited ferroptosis in both rat and cellular models. Network pharmacology and molecular docking implicated KEAP1/NRF2 pathway as a potential target of oleanolic acid. Indeed, OA experimentally upregulated NRF2 activity, which underlies its inhibition of ferroptosis and protection against IRI. The gut microbial metabolite OA protects against IRI in severe steatotic liver by promoting NRF2 expression and activity, thereby inhibiting ferroptosis.

Ecklonia cava Polyphenols Have a Preventive Effect on Parkinson's Disease through the Activation of the Nrf2-ARE Pathway.

Parkinson's disease (PD) is a degenerative neurological disorder defined by the deterioration and loss of dopamine-producing neurons in the substantia nigra, leading to a range of motor impairments and non-motor symptoms. The underlying mechanism of this neurodegeneration remains unclear. This research examined the neuroprotective properties of Ecklonia cava polyphenols (ECPs) in mitigating neuronal damage induced by rotenone via the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway. Using human neuroblastoma SH-SY5Y cells and PD model mice, we found that ECP, rich in the antioxidant polyphenol phlorotannin, boosted the gene expression and functionality of the antioxidant enzyme NAD(P)H quinone oxidoreductase-1. ECP also promoted Nrf2 nuclear translocation and increased p62 expression, suggesting that p62 helps sustain Nrf2 activation via a positive feedback loop. The neuroprotective effect of ECP was significantly reduced by Compound C (CC), an AMP-activated protein kinase (AMPK) inhibitor, which also suppressed Nrf2 nuclear translocation. In PD model mice, ECPs improved motor functions impaired by rotenone, as assessed by the pole test and wire-hanging test, and restored intestinal motor function and colon tissue morphology. Additionally, ECPs increased tyrosine hydroxylase expression in the substantia nigra, indicating a protective effect on dopaminergic neurons. These findings suggest that ECP has a preventative effect on PD.

Sodium selenite attenuates inflammatory response and oxidative stress injury by regulating the Nrf2/ARE pathway in contrast-induced acute kidney injury in rats.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) is an acute renal complication that occurs after intravascular contrast agent administration. Sodium selenite (SS) is an inorganic source of Se and has potent antioxidant properties. This study intends to examine its anti-inflammatory and antioxidant effects in CI-AKI. METHODS: A rat CI-AKI model was established with the pretreatment of SS (0.35 mg/kg). Hematoxylin-eosin staining was employed for histopathological analysis of rat kidney specimens. Biochemical analysis was conducted for renal function detection. Tissue levels of oxidative stress-related markers were estimated. Reverse transcription-quantitative polymerase chain reaction revealed the mRNA levels of proinflammatory cytokines. Western blotting showed the Nrf2 signaling-related protein expression in the rat kidney. RESULTS: SS administration alleviated the renal pathological changes and reduced the serum levels of serum creatinine, blood urea nitrogen, neutrophil gelatinase-associated lipocalin, cystatin C, and urinary level of kidney injury molecule-1 in CI-AKI rats. SS attenuated oxidative stress and inflammatory response in CI-AKI rat kidney tissues. SS activated the Nrf2 signaling transduction in the renal tissues of rats with CI-AKI. CONCLUSION: SS ameliorates CI-AKI in rats by reducing oxidative stress and inflammation via the Nrf2 signaling.

Hydroxygenkwanin exerts a neuroprotective effect by activating the Nrf2/ARE signaling pathway.

High levels of reactive oxygen species (ROS) have been associated with the progression of neurodegenerative diseases such as Alzheimer's disease. The activation of the NFE2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway may restore the neuron's redox balance and provide a therapeutic impact. Hydroxygenkwanin (HGK), a dominant flavone from Genkwa Flos, has received expanding attention due to its medicinal activities. Our investigation results demonstrated the ability of HGK to protect the PC12 cells from oxidative damage caused by an excessive hydrogen peroxide load. HGK also showed the ability to upregulate a panel of endogenous antioxidant proteins. Further investigations have demonstrated that the neuroprotection mechanism of HGK is dependent on the activation of the Nrf2/ARE signaling pathway. Activating the Nrf2/ARE pathway by HGK reveals a novel mechanism for understanding the pharmacological functions of HGK. These findings suggest that HGK could be considered for further development as an oxidative stress-related neurological pathologies potential therapeutic drug.

Rehmapicrogenin attenuates lipopolysaccharide-induced podocyte injury and kidney dysfunctions by regulating nuclear factor E2-related factor 2/antioxidant response element signalling.

BACKGROUND: Apoptosis and oxidative stress in kidneys are critical players in acute kidney injury (AKI). Rehmapicrogenin, a monomeric compound extracted from Rehmanniae radix, has been found to possess nitric oxide inhibitory and anti-inflammatory activities. Thus, this study aimed to investigate the roles and mechanisms of rehmapicrogenin in AKI. METHODS: Lipopolysaccharide (LPS) was used to induce AKI-like conditions. Cell survival conditions were detected by cell counting kit-8 assays and flow cytometry. Several renal function markers including blood urea nitrogen, proteinuria, creatinine, and albumin were measured. Apoptosis and reactive oxygen species (ROS) production were examined by TUNEL and dihydroethidium staining, respectively. Haematoxylin-eosin staining and periodic acid-Schiff staining were conducted to assess histopathological changes. Gene expression was evaluated by western blotting, commercially available kits and immunofluorescence staining. RESULTS: For in vitro analysis, rehmapicrogenin inhibited the LPS-induced podocyte apoptosis by activating the Nrf2/ARE pathway. For in vivo analysis, rehmapicrogenin improved renal functions in LPS-induced mice. Additionally, rehmapicrogenin suppressed LPS-induced podocyte apoptosis and oxidative stress in kidney tissues. Mechanistically, rehmapicrogenin activated the Nrf2/ARE pathway in LPS-induced mice. CONCLUSION: Rehmapicrogenin relieves the podocyte injury and renal dysfunctions through activating the Nrf2/ARE pathway to inhibit apoptosis and oxidative stress.

Role of the Nrf2/ARE Pathway in the mtDNA Reparation.

Mitochondrial DNA (mtDNA) is located in the mitochondrial matrix, in close proximity to major sources of reactive oxygen species (ROS) in the cell. This makes mtDNA one of the most susceptible components to damage in the cell. The nuclear factor E2-related factor 2/antioxidant response element (Nrf2/ARE) signaling pathway is an important cytoprotective mechanism. It is well-studied and described that Nrf2 can regulate the expression of mitochondrial-targeted antioxidant systems in the cell, indirectly protecting mtDNA from damage. However, the Nrf2/ARE pathway can also directly impact on the mtDNA repair processes. In this review, we summarize the existing data on the impact of Nrf2 on mtDNA repair, primarily base excision repair (BER), as it is considered the main repair pathway for the mitochondrial genome. We explore the crosstalk between Nrf2/ARE, BRCA1, and p53 signaling pathways in their involvement in maintaining mtDNA integrity. The role of other repair mechanisms in correcting mismatched bases and double-strand breaks is discussed. Additionally, the review addresses the role of Nrf2 in the repair of noncanonical bases, which contribute to an increased number of mutations in mtDNA and can contaminate the nucleotide pool.

Hsa_circ_0096157 silencing suppresses autophagy and reduces cisplatin resistance in non-small cell lung cancer by weakening the Nrf2/ARE signaling pathway.

BACKGROUND: Non-small cell lung cancer (NSCLC) is the leading cause of cancer morbidity and mortality worldwide, and new diagnostic markers are urgently needed. We aimed to investigate the mechanism by which hsa_circ_0096157 regulates autophagy and cisplatin (DDP) resistance in NSCLC. METHODS: A549 cells were treated with DDP (0 µg/mL or 3 µg/mL). Then, the autophagy activator rapamycin (200 nm) was applied to the A549/DDP cells. Moreover, hsa_circ_0096157 and Nrf2 were knocked down, and Nrf2 was overexpressed in A549/DDP cells. The expression of Hsa_circ_0096157, the Nrf2/ARE pathway-related factors Nrf2, HO-1, and NQO1, and the autophagy-related factors LC3, Beclin-1, and p62 was evaluated by qRT‒PCR or western blotting. Autophagosomes were detected through TEM. An MTS assay was utilized to measure cell proliferation. The associated miRNA levels were also tested by qRT‒PCR. RESULTS: DDP (3 µg/mL) promoted hsa_circ_0096157, LC3 II/I, and Beclin-1 expression and decreased p62 expression. Knocking down hsa_circ_0096157 resulted in the downregulation of LC3 II/I and Beclin-1 expression, upregulation of p62 expression, and decreased proliferation. Rapamycin reversed the effect of interfering with hsa_circ_0096157. Keap1 expression was lower, and Nrf2, HO-1, and NQO1 expression was greater in the A549/DDP group than in the A549 group. HO-1 expression was repressed after Nrf2 interference. In addition, activation of the Nrf2/ARE pathway promoted autophagy in A549/DDP cells. Moreover, hsa_circ_0096157 activated the Nrf2/ARE pathway. The silencing of hsa_circ_0096157 reduced Nrf2 expression by releasing miR-142-5p or miR-548n. Finally, we found that hsa_circ_0096157 promoted A549/DDP cell autophagy by activating the Nrf2/ARE pathway. CONCLUSION: Knockdown of hsa_circ_0096157 inhibits autophagy and DDP resistance in NSCLC cells by downregulating the Nrf2/ARE signaling pathway.