Kelch-like ECH-associated Protein Research Articles

ShRNA-interfered of Nrf2 reveals a critical role for Keap1-Nrf2 signaling pathway during effects of Zearalenone induced oxidative stress in IPEC-J2 cells.

This study aims to verify the protective effect of the Kelch-like ECH-associated protein1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways by studying the effect of plasmids containing Nrf2-small hairpin RNA (shRNA) interference down-regulation of Nrf2 on zearalenone (ZEA) -induced intestinal porcine epithelial cells (IPEC-J2) oxidative stress. We constructed an IPEC-J2 model that interferes with Nrf2 expression, set blank (Control), negative control group (Sh-control), positive control group (Sh-Nrf2), and added 10, 20, and 40 μmol/L ZEA experimental group (Sh-Nrf2+ZEA10, Sh-Nrf2+ZEA20, and Sh-Nrf2+ZEA40). The study results showed that, compared with the Sh-Nrf2 group, ZEA significantly increased the apoptosis rate of IPEC-J2 in a time- and dose-dependent manner. Compared with the Sh-Nrf2 group, the activities of T-SOD and GSH-PX and relative expressions of Keap1 at mRNA and protein level in the Sh-Nrf2+ZEA20 and Sh-Nrf2+ZEA40 groups were significantly reduced, the MDA level, and the fluorescence intensity around and within the nucleus of ROS and Nrf2, and the relative expressions of Nrf2, Nqo1, and Ho1 at mRNA and protein level significantly increased. These results further prove that interfering with the expression of Nrf2 in IPEC-J2 cells affected the activation of the Keap1-Nrf2 signaling pathway and reduced the ability of cells to resist ZEA-induced oxidative stress. Therefore, the Keap1-Nrf2 signaling pathway had an important protective effect in ZEA-induced intestinal oxidative stress.

Research on the Anti-Fatigue Effects and Mechanisms of Arecoline in Sleep-Deprived Mice.

This research aims to estimate the anti-fatigue effects of arecoline and explore its underlying mechanisms using a murine model of central fatigue precipitated by sleep deprivation (SD). Seventy-two male C57BL/6 mice were randomly assigned to six groups: a control group, an SD-induced fatigue model group, a group that received Rhodiola Rosea capsules (2.5 mg/kg), and three arecoline groups, which were administered at low, medium, and high doses (10, 20, and 40 mg/kg, respectively). Following 28 days of continuous administrations, the effects of arecoline on mouse fatigue-related behaviors were assessed by behavioral tests, including grip strength, rotarod performance, and weight-bearing swimming endurance. The release levels of the related biochemical markers were measured by enzyme-linked immunosorbent assays (ELISAs). Western blotting was employed to quantify the expression levels of nuclear factor erythroid 2-related factor (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), heme oxygenase 1 (HO-1), sequestosome-1 (p62), and NADPH quinone oxidoreductase 1 (NQO1) in the gastrocnemius muscle. Arecoline administration notably enhanced grip strength, delayed the onset of fatigue as evidenced by extended latencies in rotarod tests, and increased the duration of weight-bearing swimming in mice. In the elevated plus maze, arecoline obviously decreased both the number of entries and the total distance traveled in the open arms. Arecoline markedly decreased the contents of creatine kinase, blood urea nitrogen, lactate dehydrogenase, triglycerides, and cholesterol in the serum, while it elevated the levels of total testosterone, lactate dehydrogenase, and immunoglobulin G. Furthermore, it significantly increased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase in the gastrocnemius muscle, reduced malondialdehyde levels, augmented hippocampal SOD and CAT activity, and elevated glycogen stores in both liver and muscle tissues. Neurotransmitter levels showed significant increases, cytokine levels were markedly reduced, and the expressions of Nrf2, Keap1, NQO1, p62, and HO-1 in brain tissues were significantly upregulated. This study demonstrates that arecoline has anti-fatigue activity, and the specific mechanisms are associated with elevating glucose and lipid metabolism levels, relieving oxidative stress damage, inhibiting neuroinflammatory response, and regulating neurotransmitter levels and the Keap1/Nrf2/HO-1 signaling pathway. The research provides a new direction for arecoline's potential in preventing and improving fatigue.

Citrus Flavanone Effects on the Nrf2-Keap1/GSK3/NF-κB/NLRP3 Regulation and Corticotroph-Stress Hormone Loop in the Old Pituitary.

Oxidative stress and inflammation are significant causes of aging. At the same time, citrus flavanones, naringenin (NAR), and hesperetin (HES) are bioactives with proven antioxidant and anti-inflammatory properties. Nevertheless, there are still no data about flavanone's influence and its potential effects on the healthy aging process and improving pituitary functioning. Thus, using qPCR, immunoblot, histological techniques, and biochemical assays, our study aimed to elucidate how citrus flavanones (15 mg/kg b.m. per os) affect antioxidant defense, inflammation, and stress hormone output in the old rat model. Our results showed that HES restores the redox environment in the pituitary by down-regulating the nuclear factor erythroid 2-related factor 2 (Nrf2) protein while increasing kelch-like ECH-associated protein 1 (Keap1), thioredoxin reductase (TrxR1), and superoxide dismutase 2 (SOD2) protein expression. Immunofluorescent analysis confirmed Nrf2 and Keap1 down- and up-regulation, respectively. Supplementation with NAR increased Keap1, Trxr1, glutathione peroxidase (Gpx), and glutathione reductase (Gr) mRNA expression. Decreased oxidative stress aligned with NLRP3 decrement after both flavanones and glycogen synthase kinase-3 (GSK3) only after HES. The signal intensity of adrenocorticotropic hormone (ACTH) cells did not change, while corticosterone levels in serum decreased after both flavanones. HES showed higher potential than NAR in affecting a redox environment without increasing the inflammatory response, while a decrease in corticosterone level has a solid link to longevity. Our findings suggest that HES could improve and facilitate redox and inflammatory dysregulation in the rat's old pituitary.

Efficacy and Safety of KRASG12C Inhibitor IBI351 Monotherapy in Patients With Advanced NSCLC: Results From a Phase 2 Pivotal Study

IntroductionKRAS glycine-to-cysteine substitution at codon 12 (G12C) mutation is a well-recognized and increasingly promising therapeutic target with huge unmet clinical needs in NSCLC patients. IBI351 is a potent covalent and irreversible inhibitor of KRAS G12C. Here, we present the efficacy and safety of IBI351 from an open-label, single-arm, phase 2 pivotal study. MethodsEligible patients with NSCLC with KRAS G12C who failed standard therapy were enrolled. IBI351 was orally administered at a dose of 600 mg twice daily. The primary endpoint was confirmed objective response rate assessed by an independent radiological review committee (IRRC) as per Response Evaluation Criteria in Solid Tumors v1.1. Other endpoints were safety, IRRC-confirmed disease control rate, duration of response, progression-free survival (PFS), and overall survival. ResultsAs of December 13, 2023, 116 patients were enrolled (Eastern Cooperative Oncology Group Performance Status 1: 91.4%; brain metastasis: 30.2%; prior treatments with both anti-PD-1 or anti-PD-L1 inhibitors and platinum-based chemotherapy: 84.5%). As per the IRRC assessment, the confirmed objective response rate was 49.1% (95% confidence interval [CI]: 39.7–58.6), and the disease control rate was 90.5% (95% CI: 83.7–95.2). The median duration of response was not reached whereas disease progression or death events occurred in 22 patients (38.6%), and the median PFS was 9.7 months (95% CI: 5.6–11.0). overall survival data was immature. Treatment-related adverse events (TRAEs) occurred in 107 patients (92.2%) whereas 48 patients (41.4%) had equal to or higher than grade three TRAEs. Common TRAEs were anemia (44.8%), increased alanine aminotransferase (28.4%), increased aspartate aminotransferase (27.6%), asthenia (26.7%) and presence of protein in urine (25.0%). TRAEs leading to treatment discontinuation occurred in nine patients (7.8%). In biomarker evaluable patients (n = 95), all patients had positive KRAS G12C in tissue whereas 72 patients were blood-positive and 23 were blood-negative for KRAS G12C. Patients with KRAS G12C in both blood and tissue had higher tumor burden at baseline (p < 0.05) and worse PFS (p < 0.05). Tumor mutation profiling identified tumor protein p53 (45.3%), serine/threonine kinase 11 (STK11) (30.5%), and kelch-like ECH-associated protein 1 (21.1%) as the most common genes co-mutated with KRAS G12C. Among 13 genes with mutation frequency equal to or higher than 5%, mutations of six genes (STK11, kelch-like ECH-associated protein 1, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit gamma, DNA polymerase epsilon, SMAD family member 4, and BMP/retinoic acid-inducible neural-specific protein 3) were significantly associated with worse PFS (p < 0.05). Mutation in STK11 was also found to have a significant association with higher tumor burden at baseline and lower response rate (p < 0.05). ConclusionsIBI351 monotherapy demonstrated promising and sustained efficacy with manageable safety, supporting its potential as a new treatment option for KRAS G12C-mutant NSCLC.

Swimming training attenuates doxorubicin induced cardiomyopathy by targeting the mir-17-3p/KEAP1/NRF2 axis

Doxorubicin (DOX), as a first-line anticancer drug, is widely used in the treatment of various cancers. However, its clinical application is restricted due to its severe cardiac toxicity. Previous studies have indicated exercise training can alleviate the DOX-induced cardiotoxicity (DIC), but the underlying mechanism remains unclear. Our research has discovered, post-exercise, an elevated expression level of mir-17-3p, but in DIC its level decreases. Therefore, we further studied the effect of exercise mir-17-3p axis on DIC. In vivo, we simulated DIC mouse model, followed by an intervention using swimming and adenovirus to inhibit mir-17-3p. We found that inhibition of mir-17-3p can weaken the protection of exercise against DIC, presenting as weakened heart function. Besides, the levels of Malondialdehyde and Fe2+ in the cardiac tissue increased, along with diminished glutathione peroxidase 4 and Solute Carrier Family 7 Member 11 levels, and a decline in the concentration of glutathione, causing an increase in ferroptosis. Moreover, in vitro, we used dual-luciferase assay to confirm that Kelch Like ECH Associated Protein 1 (KEAP1) can be a target gene of mir-17-3p. We used Keap1/NFE2 Like BZIP Transcription Factor 2 (NRF2) inhibitor brusatol and Stimulator of Interferon Response CGAMP Interactor 1 (STING) agonist SR-717 to verify the mir-17-3p/KEAP1 axis can affect the Cyclic GMP-AMP Synthase (CGAS)/STING pathway, leading to further ferroptosis in DIC. This manifested as a reduction in ferroptosis. In summary, our research suggests swimming training enhances the levels of mir-17-3p, thereby activating the KEAP1/NRF2 pathway, and weakening the CGAS/STING pathway, improving ferroptosis in DIC.

Effects of oligomeric proanthocyanidins on growth performance, antioxidant capability, immunity, liver and intestinal health of Channa argus

To determine the effects of proanthocyanidins on the growth, antioxidant capability, immunity, intestinal morphology, intestinal microbiota, and liver health of Channa argus (10.12 ± 0.12 g), four experimental diets with various oligomeric proanthocyanidin (OPC) concentrations (0, 200, 400, and 800 mg/kg) were fed to triplicate groups for 8 weeks. The final body weight (FBW), weight gain (WG), feeding rate (FER), protein efficiency ratio (PER), and specific growth rate (SGR) were significantly improved in the 400 and 800 mg/kg OPC-supplemented diets (P < 0.05). The superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione (GSH), catalase (CAT), and glutathione peroxidase (GSH-Px) activities in the liver and intestines were increased significantly, whereas the malondialdehyde (MDA) content exhibited the opposite pattern (P < 0.05). The GST, Cu/Zn superoxide dismutase (Cu/Zn SOD), nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO-1), and heme oxygenase 1 (HO-1) mRNA expression levels in the intestines and liver were significantly increased, whereas kelch-like ECH-associated protein 1 (Keap1) expression showed the opposite pattern (P < 0.05). Significant increases were noted in the serum lysozyme (LYS), immunoglobulin M (IgM), complement 3 (C3), and complement 4 (C4) levels, and significant decreases were noted in the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bile acid (TBA), and total cholesterol (TC) levels (P < 0.05). The interferon gamma (IFN-γ), interleukin-8 (IL-8), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) mRNA expression levels in the liver and intestines were significantly decreased, whereas the expression of interleukin-10 (IL-10) showed the opposite trend (P < 0.05). Compared with the control diet, the 400 and 800 mg/kg OPC-supplemented diets markedly improved liver and intestinal morphology. With increasing OPC concentration, the relative abundance of the beneficial bacteria, namely, Firmicutes increased, whereas the opposite trend was observed for the potential pathogenic bacteria, namely, Proteobacteria, Actinobacteria, Chlamydiae, Bacteroidetes, Cyanobacteria, and Acidobacteria. Therefore, dietary OPC supplementation facilitates growth performance and enhances antioxidant capability and immunity, as well as improves liver health, intestinal morphology, and microbiota composition of C. argus, of which the optimal level is 400 mg/kg.

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

BackgroundAging-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. MethodsTricolor guinea pigs were used for the experiments in vivo and primary guinea pig ciliary smooth muscle cells were used for the experiments in vitro. ResultsWe 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 activated senescence β-galactosidase (SA-β-Gal) and ROS levels, 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. Conclusionlutein 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.

Caffeic acid ameliorates metabolic dysfunction-associated steatotic liver disease via alleviating oxidative damage and lipid accumulation in hepatocytes through activating Nrf2 via targeting Keap1

Metabolic-associated steatotic liver disease (MASLD), known as non-alcoholic fatty liver disease (NAFLD) in the past, encompasses a range of liver pathological conditions marked by the excessive lipid accumulation. Consumption of coffee is closely associated with the reduced risk of MASLD. Caffeic acid (CA), a key active ingredient in coffee, exhibits notable hepatoprotective properties. This study aims to investigate the improvement of CA on MASLD and the engaged mechanism. Mice underwent a 12-week high-fat diet (HFD) regimen to induce MASLD, and liver pathology was assessed using hematoxylin-eosin (H&E) and oil red O (ORO) staining. Hepatic inflammation was evaluated by F4/80 and Ly6G immunohistochemistry (IHC) and myeloperoxidase (MPO) measurement. Pathways and transcription factors relevant to MASLD were analyzed by using microarray data from patients’ livers. Oxidative damage was evaluated by detecting reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). Co-immunoprecipitation (CoIP), cellular thermal shift assay (CETSA) and surface plasmon resonance (SPR) were used to validate the binding between CA and its target protein. CA significantly alleviated liver damage, steatosis and inflammatory injury, and reduced the elevated NAFLD activity score (NAS) in HFD-fed mice. Clinical data indicate that fatty acid metabolism and ROS generation are pivotal in MASLD progression. CA increased the expression of fibroblast growth factor 21 (FGF21), FGF receptor 1 (FGFR1) and β-Klotho (KLB), and promoted fatty acid consumption. Additionally, CA mitigated oxidative stress injury and activated nuclear factor erythroid 2-related factor-2 (Nrf2). In primary hepatocytes isolated from Nrf2 knockout mice, CA’s promotion on FGF21 release and inhibition on oxidative stress and lipotoxicity was disappeared. CA could directly bind to kelch-like ECH-associated protein 1 (Keap1) that is an Nrf2 inhibitor protein. This study suggests that CA alleviates MASLD by reducing hepatic lipid accumulation, lipotoxicity and oxidative damage through activating Nrf2 via binding to Keap1.

Paternal exercise induces antioxidant defenses by α-Klotho/Keap1 pathways in the skeletal muscle of offspring exposed to a high fat-diet without changing telomere length

Although previous studies demonstrated that the ancestral lifestyle can enhance the metabolic health of offspring exposed to an obesogenic diet, the specific connections between these positive effects in redox state and telomere length are unknown. We investigated the impact of paternal resistance training (RT) on stress-responsive signaling and the pathways involved in telomere homeostasis in skeletal muscle. This investigation encompassed both the fathers and first-generation litter exposed to a long-term standard diet (24 weeks) and high fat diet (HFD). Wistar rats were randomized into sedentary or trained fathers (8 weeks of resistance training). The offspring were obtained by mating with sedentary females. Upon weaning, male offspring were divided into four groups: offspring of sedentary or trained fathers exposed to either a control diet or HFD. The gastrocnemius was prepared for reverse transcription-quantitative polymerase chain reaction, immunoblotting, ELISA, and electron paramagnetic resonance spectroscopy. RT upregulated shelterin mRNA levels and antioxidant protein, preserving muscle telomere in fathers. Conversely, HFD induced a disturbance in the redox balance, which may have contributed to the offspring telomere shortening from sedentary fathers. Pre-conceptional paternal RT downregulates Kelch-like ECH-associated protein 1 (Keap1) mRNA levels in the skeletal muscle of progeny exposed to HFD, driving an increase in Glutathione reductase mRNA levels, Sod1 and Catalase protein levels to mitigate ROS production. Also, paternal exercise upregulates α-Klotho protein levels, mediating antioxidative responses without altering shelterin mRNA levels and telomere length. We provide the first in-depth analysis that the offspring's redox state seems to be directly associated with the beneficial effects of paternal exercise.

Role of hypoxia-inducible-factor-1α (HIF-1α) in ferroptosis of adipose tissue during ketosis

Postpartum cows experience lipolysis in adipose tissue due to negative energy balance (NEB), and accumulation of free fatty acids (FFA) leads to metabolic stress in adipose tissue. Ferroptosis is a type of cell death triggered by excessive buildup of iron-dependent lipid peroxides, which is involved in the occurrence and development of various metabolic diseases in nonruminants. However, it is still unclear whether ferroptosis occurs in the adipose tissue of ketotic cows and the regulatory mechanisms behind ferroptosis. Despite multiple studies demonstrating the significant involvement of hypoxia-inducible-factor-1α (HIF-1α) in regulating cellular dysfunction, its specific function in adipose tissue of ketotic dairy cows remains uncertain, particularly its regulation of oxidative stress and ferroptosis. The study aimed to explore the impact of HIF-1α on oxidative stress and ferroptosis in bovine subcutaneous adipose tissue and isolated adipocytes. The adipose tissue of clinical ketosis cows (n = 15) with a serum BHB concentration of 3.13 mM (interquartile range = 0.14) and healthy cows (n = 15) with a serum BHB concentration of and 0.58 mM (interquartile range = 0.13) was collected. The results showed that the concentrations of lipid peroxidation malondialdehyde (MDA), reactive oxygen species (ROS), Fe2+ and total iron were increased in adipose tissue of cows with ketosis, while the contents of glutathione (GSH) were reduced. Furthermore, the protein levels of HIF-1α, heme oxygenase 1 (HMOX1), catalase (CAT), superoxide dismutase 1 (SOD1), acyl-CoA synthetase 4 (ACSL4), and nuclear factor erythroid-derived 2-like 2 (NFE2L2) exhibited higher abundance in adipose tissue obtained from cows with ketosis, whereas the protein abundance of solute carrier family 7 member 11 (SLC7A11), glutamate cysteine ligase catalytic subunit (GCLC), kelch-like ECH-associated protein 1 (KEAP1), glutamate cysteine ligase regulatory subunit (GCLM) and glutathione peroxidase 4 (GPX4) were lower. To simulate the ferroptosis state of adipose tissue in ketotic cows, primary bovine adipocytes were isolated from the adipose tissue of healthy cows and cultured with erastin to construct ferroptosis model. Adipocytes were cultured with either an adenovirus overexpressing HIF-1α or small interfering RNA targeting HIF-for 48 h, followed by exposure to erastin (1 μM) for 24 h. Treatment with erastin led to higher protein abundance of CAT, SOD1, NFE2L2 and HMOX1, while it inhibited the protein expression levels of GCLC, SLC7A11, GCLM, GPX4 and KEAP1. Furthermore, erastin treatment elevated the levels of ROS, MDA, Fe2+, total iron and reduced the content of GSH. The overexpression of HIF-1α reversed the erastin-induced decreases in the protein abundance of GPX4 and SLC7A11, as well as the levels of MDA, ROS, Fe2+ and total iron, while significantly increasing protein abundance and content of CAT, SOD1, NFE2L2, HMOX1, GCLC, GCLM, GPX4, SLC7A11 and GSH. Conversely, the silencing of HIF-1α further exacerbated the erastin-induced levels of MDA, ROS, Fe2+ and total iron, while inhibiting the upregulation of SOD1, CAT, NFE2L2 and HMOX1. Collectively, these findings suggest that activation of HIF-1α may function as an adaptive mechanism to mitigate ferroptosis and alleviate oxidative stress in adipose tissue.

Unlocking milk thistle’s anti-psoriatic potential in mice: Targeting PI3K/AKT/mTOR and KEAP1/NRF2/NF-κB pathways to modulate inflammation and oxidative stress

Silybum marianum, known as milk thistle (MT), is traditionally used to manage liver diseases. This study aimed to investigate the role of MT extract topical application as a potential treatment for imiquimod (IMQ)-induced psoriatic lesions in mice with particular emphasis on phosphoinositol-3 Kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) and Kelch-like ECH-associated protein 1 (KEAP1)/ nuclear factor erythroid-2-related factor (NRF2)/ nuclear factor-kappa B (NF-κB) molecular cascades involvement. To address this aim, forty male Swiss albino mice were subdivided into four groups (n = 10 mice/group): control, IMQ model, standard group where mice were treated topically with IMQ, then the anti-psoriatic mometasone cream, and MT extract-treated group where mice were treated topically with IMQ followed by MT extract. In most measured parameters, MT extract, rich in silymarin, exhibited potent anti-psoriatic activity comparable to the standard cortisone treatment. MT extract mitigated dorsal skin erythema, scaling, and epidermal thickening, reflected by lowering the Psoriasis Area Severity Index (PASI) score. Moreover, it alleviated IMQ-induced splenomegaly. Mechanistically, the PI3K/AKT/mTOR pathway was the main functional pathway behind such improvements, where it was significantly inhibited by MT extract application. This led to NRF2 activation via KEAP1 downregulation with subsequent anti-inflammatory effect proven by reducing NF-κB, interleukin (IL)–23, and IL-17A and antioxidant ability proven by boosting the antioxidant glutathione and heme oxygenase-1. Such improvements were confirmed by alleviating the histopathological alteration. Thus, MT extract could be a promising therapeutic agent for psoriasis treatment by inhibiting PI3K/AKT/mTOR cascade, along with NRF2 signaling activation.

Oxidised rice bran oil induced oxidative stress and apoptosis in IPEC-J2 cells via the Nrf2 signalling pathway.

Rice bran oil is a type of rice oil made by leaching or pressing during rice processing and has a high absorption rate after consumption. When oxidative rancidity occurs, it may cause oxidative stress (OS) and affect intestinal function. Meanwhile, the toxic effects of oxidised rice bran oil have been less well studied in pigs. Therefore, the IPEC-J2 cells model was chosen to explore the regulatory mechanisms of oxidised rice bran oil on OSand apoptosis. Oxidised rice bran oil extract treatment(OR) significantly decreased the viability of IPEC-J2 cells. The results showed that OR significantly elevated apoptosis and reactive oxygen species levelsand promoted the expression of pro-apoptotic gene Caspase-3 messenger RNA levels. The activation of Nrf2 signalling pathway by OR decreased the cellular antioxidant capacity. This was further evidenced by the expression of kelch-like ECH-associated protein 1, heme oxygenase 1, NADH: quinone oxidoreductase 1, superoxide dismutase2and heat shock 70 kDa protein genes and proteins were all downregulated. In conclusion, our results suggested that oxidised rice bran oil induced damage in IPEC-J2 cells through the Nrf2 signalling pathway.

Shengqing Jiangzhuo capsule ameliorates diabetic nephropathy by improving Keap1/Nrf2 signaling pathway.

Diabetic nephropathy (DN) is a major contributor to end-stage renal failure, and lacking effective treatment options. Shengqing Jiangzhuo capsule (SQJZJN), a traditional Chinese medicine prescription with known efficacy in chronic kidney disease, has not been thoroughly investigated for its potential in DN protection. Eight-week-old male C57BLKS/J db/db, C57BLKS/J db/m mice, and human glomerular mesangial cell (HMC) cells cultured with high glucose were used as experimental models in this study. The in vivo investigation showed that SQJZJN can significantly ameliorate renal pathological damage, reduce serum creatinine, and lower urinary microalbumin levels in db/db mice. In vitro, SQJZJN treatment mitigated advanced glycation end products (AGEs) and reactive oxygen species (ROS), leading to a reduction in renal cell apoptosis. Mechanistically, SQJZJN activated the Keap1/Nrf2/ARE pathway by promoting nuclear factor erythroid-derived 2-related factor 2 (Nrf2), γ-glutamylcysteine synthetase heavy subunit (γ-GCS), and Heme oxygenase-1 (HO-1) expressions, while decreasing Kelch-like ECH-associated protein 1 (KEAP1) expressions. These findings suggest that SQJZJN exerts a protective effect on DN, potentially through the activation of the Keap1/Nrf2/ARE pathway.

Regulation of Keap1-Nrf2 signaling in health and diseases.

Nuclear factor erythroid 2-related factor 2 (Nrf2) functions as a central regulator in modulating the activities of diverse antioxidant enzymes, maintaining cellular redox balance, and responding to oxidative stress (OS). Kelch-like ECH-associated protein 1 (Keap1) serves as a principal negative modulator in controlling the expression of detoxification and antioxidant genes. It is widely accepted that OS plays a pivotal role in the pathogenesis of various diseases. When OS occurs, leading to inflammatory infiltration of neutrophils, increased secretion of proteases, and the generation of large quantities of reactive oxygen radicals (ROS). These ROS can oxidize or disrupt DNA, lipids, and proteins either directly or indirectly. They also cause gene mutations, lipid peroxidation, and protein denaturation, all of which can result in disease. The Keap1-Nrf2 signaling pathway regulates the balance between oxidants and antioxidants in vivo, maintains the stability of the intracellular environment, and promotes cell growth and repair. However, the antioxidant properties of the Keap1-Nrf2 signaling pathway are reduced in disease. This review overviews the mechanisms of OS generation, the biological properties of Keap1-Nrf2, and the regulatory role of its pathway in health and disease, to explore therapeutic strategies for the Keap1-Nrf2 signaling pathway in different diseases.

Adenosine A2A Receptor Antagonist Sch58261 Improves the Cognitive Function in Alzheimer's Disease Model Mice Through Activation of Nrf2 via an Autophagy-Dependent Pathway.

Aims: Adenosine, an important endogenous neuromodulator, contributes to a broad set of several neurodegenerative diseases. The adenosine A2A receptor (A2AR) is the most involved in neuropathological effects and plays an important role in the pathogenesis of Alzheimer's disease (AD). However, the effect of A2AR antagonist and the underlying mechanism in AD model mice remains unclear. Results: The amyloid beta (Aβ)1-42-induced mice AD models were used in this study. Several behavioral experiments were performed to evaluate the improvement of AD mice treated with A2AR antagonist. For mechanism analysis, autophagy-related proteins, Kelch-like ECH-associated protein1 (Keap1)-nuclear factor erythroid-derived factor 2-related factor (Nrf2) pathway activation, and synaptic function were studied using Western blot, immunofluorescence, immunohistochemistry, transmission electron microscope, real-time quantitative PCR, and patch clamp. Pharmacological blockade of adenosine A2AR by SCH58261 (SCH) ameliorated cognitive deficits and decreased expression levels of several AD biomarkers, including Aβ and hyperphosphorylation of Tau. Moreover, SCH activated the Nrf2 pathway through autophagy mediated Keap1 degradation, resulting in the improvement of neuron autophagy dysfunction, synaptic plasticity, and synaptic transmission. Innovation: Our data clarified that the SCH (an antagonist of A2AR) could increase the level of autophagy, promote the ability of antioxidative stress by the activation of Keap1-Nrf2 pathway, and improve the synaptic function in Aβ1-42-induced AD mice or cell model, which provided a potential therapeutic strategy for AD. Conclusion: A2AR antagonism represents a promising strategy for the anti-AD agent development through autophagy-dependent pathway.

Redox-state-regulating enzymes have prognostic value in diabetic endometrial cancer patients: impact of statin use?

The incidence of endometrial cancer is increasing, and oxidative stress has been suggested to play a vital role in its carcinogenesis. Statins have an impact on the cellular redox-state. The aim of this study was to determine the effects of statin use on redox-state regulating enzymes in endometrial cancer in women with type 2 diabetes. This retrospective study consisted of 119 women with type 2 diabetes who were diagnosed with endometrial cancer at Oulu University Hospital in Finland between 2007 and 2014. There were 58 statin users and 61 non-users based on medication use at the time of endometrial cancer diagnosis. The expression of redox-state regulating proteins nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) in the tumor samples was assessed immunohistochemically, and manganese superoxide dismutase (MnSOD) levels were measured both immunohistochemically and from serum samples. High MnSOD expression predicted better progression-free survival (PFS) in statin non-users in a univariate analysis (p=0.02). There was no statistical difference in overall survival (OS) or PFS between strong and weak expression of Nrf2 and Keap1. After adjusting for stage and statin use, the results were similar. Statin non-users with strong MnSOD expression had better PFS compared to statin users which proves that statins have impact on redox-state regulating enzymes. However, these findings are preliminary and require further research.

Sakuranetin counteracts polyethylene microplastics induced nephrotoxic effects via modulation of Nrf2/Keap1 pathway

Polyethylene microplastics (PEMPs) are widely distributed in environment and exerts deleterious effects on animal as well as human health. Sakuranetin (SKN) is a natural flavonoid that manifests profound therapeutic potential. Albino rats (n = 24) were partitioned into 4 groups i.e., Control, PEMPs 1.5 mg/kg, PEMPs 1.5 mg/kg + SKN 10 mg/kg and SKN 10 mg/kg administered group. After 30 days of treatment, our results revealed that PEMPs exposure reduced nuclear factor erythroid 2–related factor 2 (Nrf-2) and antioxidant genes while enhancing the expression of kelch-like ECH-associated protein 1(Keap-1). Besides, PEMPs intoxication reduced the level of renal biomarkers i.e., creatinine clearance and increased the level of creatinine, urea, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). Additionally, it lessened the activities of glutathione S-transferase (GST), superoxide dismutase (SOD), glutathione reductase (GSR), catalase (CAT), glutathione peroxidase (GPx) and heme oxygenase-1 (HO-1) whereas the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) were increased. Conversely, it increased the levels of nuclear factor-kappa B (NF-kB), tumor necrosis factor-alpha (TNF-a), interleukin-1beta (IL-1b) and IL-6 as well as escalated the activity of cyclooxygenase-2 (COX-2). Furthermore, the expression of bcl-2-associated X protein (Bax) and caspase-3 were elevated, while the expression of B-cell lymphoma 2 (Bcl-2) was lowered. However, SKN treatment significantly (P < 0.05) restored aforementioned renal impairments. Therefore, it is proposed that SKN may be applied as a nephroprotective agent against the PEMPs-prompted renal toxicity.

PDK4-mediated Nrf2 inactivation contributes to oxidative stress and diabetic kidney injury

Diabetic kidney disease (DKD) is often featured with redox dyshomeostatis. Pyruvate dehydrogenase kinase 4 (PDK4) is the hub for DKD development. However, the mechanism by which PDK4 mediates DKD is poorly understood. The current work aimed to elucidate the relationship between PDK4 and DKD from the perspective of redox manipulation. Oxidative stress was observed in the human proximal tubular cell line (HK-2 cells) treated with a high concentration of glucose and palmitic acid (HGL). The mechanistic study showed that PDK4 could upregulate Kelch-like ECH-associated protein 1 (Keap1) in HGL-treated HK-2 cells through the suppression of autophagy, resulting in the depletion of nuclear factor erythroid 2-related factor 2 (Nrf2), the master regulator of redox homeostasis. At the cellular level, pharmacological inhibition or genetic knockdown of PDK4 could boost Nrf2, followed by the increase of a plethora of antioxidant enzymes and ferroptosis-suppression enzymes. Meanwhile, the inhibition or knockdown of PDK4 remodeled iron metabolism, further mitigating oxidative stress and lipid peroxidation. The same trend was observed in the DKD mice model. The current work highlighted the role of PDK4 in the development of DKD and suggested that PDK4 might be a promising target for the management of DKD.

In Vitro Protective Effect of Pea-Derived Peptides (PPs) via the Keap1/Nrf2 Signaling Pathway on Alpha-Gliadin-Sensitizing Peptide Induced Cacao-2 Cells.

Celiac disease (CD) is an allergic intestinal disease caused mainly by gliadin in wheat, which is widespread in the population and currently lacks effective treatment. α-Gliadin peptides cause cellular damage by substantially increasing cellular reactive oxygen species (ROS) levels. This study investigates the protective effect of 11 pea-derived peptides (PPs) on ɑ-gliadin peptide (P31-43) treated Caco-2 cells. Results show that cells treated with PP2, PP5, and PP6 peptides significantly reduce the cell mortality caused by P31-43. Three PPs significantly reduce the P31-43-induced decrease in ROS levels to control levels, and there is no difference between them and the vitamin C (Vc) group. The results in terms of antioxidant-related enzymes show that PPs significantly decrease superoxide dismutase activity (SOD), glutathione reductases (GR), and glutathione (GSH)/oxidized glutathione (GSSG) levels, thus significantly enhancing the antioxidant level of cells. By studying the key proteins of the Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor 2 (Nrf2) pathway, it is found that PPs activate the Keap1/Nrf2 signaling pathway. The study finds that peptides from peas can effectively alleviate ɑ-gliadin peptide-induced cell damage. The discovery of these food-derived peptides provides novel potential solutions for the prevention and treatment of CD.

Reduction of the oxidative damage to H2O2-induced HepG2 cells via the Nrf2 signalling pathway by plant flavonoids Quercetin and Hyperoside

Hyperoside and quercetin are similar in molecular structures. In this study, the antioxidant regulatory targets of hyperoside and quercetin are mainly in the nuclear factor (erythroid-2-derived)-related factor 2 (Nrf2) pathway predicted by network pharmacology. And the antioxidant effect and mechanism of hyperoside and quercetin were measured and compared in H2O2-induced HepG2 cells and Caenorhabditis elegans. The findings indicated that quercetin was more effective than hyperoside in reducing oxidative damage, which was proved by improved cell viability, decreased reactive oxygen species (ROS) production, decreased cellular apoptosis, and alleviated mitochondrial damage. In addition, quercetin was more efficient than hyperoside in enhancing the expression of Nrf2-associated mRNAs, increasing the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), and reducing the cellular malondialdehyde (MDA) content. Quercetin was superior to hyperoside in prolonging the lifespan of worms, decreasing the accumulation of lipofuscin, inhibiting ROS production, and increasing the proportion of skn-1 in the nucleus. With the Nrf2 inhibitor ML385, we verified that quercetin and hyperoside primarily protected the cells against oxidative damage via the Nrf2 signalling pathway. Furthermore, molecular docking and dynamics simulations demonstrated that the quercetin- Kelch-like ECH-associated protein 1 (Keap1) complex was more stable than the hyperoside-Keap1 complex. The stable structure of the complex might hinder the binding of Nrf2 and Keap1 to release Nrf2 and facilitate its entry into the nucleus to play an antioxidant role. Overall, quercetin had a better antioxidant than hyperoside.