Nrf2 Pathway Research Articles

SIRT5 participates in the suppressive tumor immune microenvironment of EGFR-mutant LUAD by regulating the succinylation of ACAT1

Epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma (LUAD) exhibits a poor response to immune checkpoint inhibitors (ICIs) by shaping a suppressive tumor immune microenvironment (TIME), which characters as lacking immune cell infiltration; however, the underlying mechanism remains to be elucidated. Here, we demonstrated that Sirtuin 5 (SIRT5), a member of the deacetylase SIRT family, functions as a desuccinylase of acetyl-CoA acetyltransferase 1 (ACAT1) and enhances the enzymatic activity of ACAT1 to activate the NRF2 pathway, inhibiting the secretion of the chemokines CCL5 and CXCL10, which are important for recruiting CD8+ T cells, thereby participating in the formation of an inhibitory TIME in EGFR-mutant LUAD. In conclusion, we propose that the combination of a SIRT5 inhibitor with ICIs therapy may be a promising therapeutic approach for patients with EGFR-mutant LUAD.

Quinic acid protects against the development of Huntington’s disease in Caenorhabditis elegans model

BackgroundQuinic acid (QA), a cyclitol and cyclohexanecarboxylic acid, is a natural product that is present and can be isolated from edible herbals like tea, coffee and several fruits and vegetables. It was previously reported that QA exerted antioxidant and neuroprotective activity against dementia. However, it was not tested for its neuroprotective potential against Huntington’s disease (HD). Since aging related disorders are greatly linked to oxidative stress conditions, we focused on testing the oxidative stress resistant activity and protective effect of QA against the development of HD by using the multicellular Caenorhabditis elegans (C. elegans) worm model.MethodsFirstly, QA was tested for its oxidative stress resistant properties. In survival assay, wild type and mutant skn-1 and daf-16 worms were exposed to oxidative stress conditions by using H2O2. Activation of SKN-1 pathway and expression of its downstream genes gcs-1 and gst-4 were also tested. Secondly, the effect of QA was evaluated on HD by testing its ability to decrease the formation of polyQ150 aggregates. Furthermore, its effect on the accumulation of polyglutamine (polyQ35 and polyQ40 aggregates) was tested.ResultsHere we report that QA could improve the survival of C. elegans after exposure to oxidative stress caused by H2O2 while also exerting antioxidant effects through the activation of SKN-1/Nrf2 pathway. Moreover, QA could be a potential candidate to protect against HD due to its effects on decreasing the formation of polyQ150, polyQ35 and polyQ40 aggregates.ConclusionsThis study highlights the importance of QA as a natural compound in defending against oxidative stress and the development of neurodegenerative diseases like HD.

Roasted Astragalus membranaceus Inhibits Aβ25–35-Induced Oxidative Stress in Neuronal Cells by Activating the Nrf2/HO-1 and AKT/CREB/BDNF Pathways

(1) Background: Astragalus membranaceus (AM) has antioxidant and anti-inflammatory effects, but its specific mechanism of action in the brain is still unclear. In this study, we developed a roasting process to maximize the cognitive improvement impact of AM. We focused on enhancing physiological activity to enhance the brain neuron protection effect and alleviate neuronal damage caused by neurodegenerative diseases. (2) Methods: AM was roasted at 260 °C for 20, 30, or 40 min, and the hot water extracts were tested on HT22 cells for ROS levels, apoptosis, and antioxidant protein expression. The effect on the BDNF-AKT-CREB pathway under stress was also analyzed. (3) Results: Roasted AM decreased ROS production and the expression of apoptosis-related factors while activating the expression of antioxidant proteins in HT22 cells treated with Aβ25–35. In particular, 30 min roasting (R-AM2) significantly reduced ROS production, inhibited cell death, and increased antioxidant protein expression. The Nrf2 pathway was activated Bax, and cleaved caspase-3 levels were reduced. BDNF and p-CREB expression were increased by 20% and 50–70%, respectively. In the MAPK pathway, p-ERK levels were increased by 30%, and p-P38 levels were increased by approximately 20%. (4) Conclusions: These findings suggest that roasted AM upregulates brain-derived neurotrophic factor (BDNF) in HT22 cells, providing neuroprotective effects by activating the AKT/CREB/BDNF pathway and inhibiting neuronal apoptosis. Therefore, roasted AM shows potential as a neuroprotective agent for preventing or treating neurodegenerative diseases, such as Alzheimer’s, linked to BDNF deficiency.

An integrated proteomics and metabolomics analysis of methylglyoxal-induced neurotoxicity in a human neuroblastoma cell line

This study aimed to highlight the molecular and biochemical changes induced by methylglyoxal (MGO) exposure in SH-SY5Y human neuroblastoma cells, and to explore how these changes contribute to its neurotoxicity, utilizing an integrated proteomics and metabolomics approach. Using label-free quantitative nanoLC-MS/MS proteomics and targeted LC-TQ-MS/MS-based metabolomics, the results revealed that MGO exposure, particularly at cytotoxic levels, significantly altered the proteome and metabolome of SH-SY5Y cells. Analysis of proteomics data showed significant alterations in cellular functions including protein synthesis, cellular structural integrity, mitochondrial function, and oxidative stress responses. Analysis of metabolomics and integration of metabolomics and proteomics data highlighted significant changes in key metabolic pathways including arginine biosynthesis, glutathione metabolism, cysteine and methionine metabolism, and the tricarboxylic acid cycle. These results suggest that MGO exposure induced both toxic effects and adaptive responses in cells. MGO exposure led to increased endoplasmic reticulum stress, disruptions in cellular adhesion and extracellular matrix integrity, mitochondrial dysfunction, and amino acid metabolism disruption, contributing to cellular toxicity. Conversely, cells exhibited adaptive responses by upregulating protein synthesis, activating the Nrf2 pathway, and reprogramming metabolism to counteract dicarbonyl stress and maintain energy levels. Furthermore, a set of key proteins and metabolites associated with these changes were shown to exhibit a significant concentration-dependent decrease or increase in their expression levels with increasing MGO concentrations, suggesting their potential as biomarkers for MGO exposure. Taken together, these findings provide insight into the molecular mechanisms underlying MGO-induced neurotoxicity and potential targets for therapeutic intervention.

Chemical composition of anti-microbially active fractions derived from extract of filamentous fungus Keratinophyton Lemmensii including three novel bioactive compounds

Screening for new bioactive microbial metabolites, we found a novel okaramine derivative, for which we propose the trivial name lemmokaramine, as well as two already known okaramine congeners – okaramine H and okaramine J - responsible for antimicrobial activity of the recently described microscopic filamentous fungus, Keratinophyton lemmensii BiMM-F76 (= CCF 6359). In addition, two novel substances, a new cyclohexyl denominated lemmensihexol and a new tetrahydroxypyrane denominated lemmensipyrane, were purified and characterized. The compounds were isolated from the culture extract of the fungus grown on modified yeast extract sucrose medium by means of flash chromatography followed by preparative HPLC. The chemical structures were elucidated by NMR and LC-MS. The new okaramine (lemmokaramine) exerted antimicrobial activity against Gram-positive and Gram-negative bacteria, yeasts and fungi and anticancer activity against different mammalian cell lines (Caco-2, HCT116, HT29, SW480, MCM G1, and MCM DLN). Furthermore, we found a significant antioxidant effect of lemmokaramine following H2O2 treatment indicated by activation of the Nrf2 pathway. This is the first report describing analysis and structural elucidation of bioactive metabolites for the onygenalean genus Keratinophyton.

Extracellular Vesicles Derived from Adipose-Derived Mesenchymal Stem Cells Alleviate Apoptosis and Oxidative Stress of Retinal Pigment Epithelial Cells Through Activation of Nrf2 Signaling Pathway.

Purpose: To examine the potential protective effects of adipose-derived mesenchymal stem cell-derived extracellular vesicles (ASC-EVs) on ARPE-19 cells exposed to hydrogen peroxide (H2O2) stress and to evaluate their ability to delay retinal degeneration in Royal College of Surgeons (RCS) rats. Methods: ARPE-19 cells were pre-treated with ASC-EVs for 24 h, followed by exposure to 200 μM H2O2 for an additional 24 h. RCS rats received an intravitreal injection of phosphate-buffered saline in one eye and ASC-EVs in the other eye. Results: ASC-EV pretreatment significantly protected against H2O2 in the Cell Counting Kit-8 assay and was also effective in the lactate dehydrogenase-release assay. It notably reduced early apoptosis (Annexin V-fluorescein isothiocyanate/propidium iodide assay) and late apoptosis (Terminal Deoxynucleotidyl Transferase dUTP Nick End Labeling assay), while significantly decreasing intracellular reactive oxygen species, glutathione levels, and superoxide dismutase activity. NFE2L2, HMOX1, and NQO1 mRNA levels, along with Nrf2, HO-1, and NQO1 protein levels, were significantly elevated with ASC-EV pretreatment. Compared with ARPE-19-derived EVs, 11 miRNAs were upregulated and 34 were downregulated in ASC-EVs. In RCS rats, intravitreal injections of ASC-EVs led to significant preservation of the outer nuclear layer and photoreceptor segments, along with increased nuclear Nrf2 expression and elevated HO-1 and NQO1 levels in the inner retina. Eyes that received intravitreal injections of ASC-EVs demonstrated significantly preserved electroretinography a- and b-wave amplitudes at 1 week post-injection, though this effect faded by 2 weeks. Conclusions: ASC-EVs mitigated apoptosis and oxidative stress in ARPE-19 cells subjected to H2O2 exposure and temporarily slowed retinal degeneration in RCS rats via Nrf2 pathway activation by miRNAs.

3,5-Dihydroxy-4-methoxybenzyl alcohol, a novel antioxidant isolated from oyster meat, inhibits the hypothalamus–pituitary–adrenal axis to regulate the stress response

BackgroundAntioxidants that can scavenge reactive oxygen in the brain and inhibit hyperactivity of the HPA axis are desirable. AimsWe investigated the cerebral translocation of the antioxidant 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA) and the effects of DHMBA administration on the hypothalamus–pituitary–adrenal (HPA) axis in stress-loaded rats. MethodsExperiment 1: Plasma and brain DHMBA concentrations were measured over time after oral DHMBA administration to female B6 mice. Experiment 2: Female Wistar Imamichi rats were used. The normal group was not subjected to stress. The stress, DHMBA, and vitamin E groups were subjected to individual and overcrowding stress. Brain and hippocampal 8-hydroxy-2′-deoxyguanosine levels, hippocampal glucocorticoid receptor-α levels, plasma corticosterone levels and RNA levels of glutathione peroxidase 4, catalase, and glutathione reductase in the hippocampus were measured. ResultsIn Experiment 1, DHMBA was not detected in the plasma or brain before DHMBA administration but was detected in both after administration. In Experiment 2, brain and hippocampal 8-hydroxy-2′-deoxyguanosine levels and plasma corticosterone levels were significantly lower in the DHMBA than in the stress group. Glucocorticoid receptor-α levels were higher in the DHMBA than in the stress group. DHMBA increased RNA levels of antioxidant enzymes in the hippocampus. Conclusion: DHMBA was translocated to the brain after administration. DHMBA administration decreased 8-hydroxy-2′-deoxyguanosine levels in the brain and hippocampus, increased hippocampal glucocorticoid receptor-α levels, and decreased the plasma corticosterone concentration, suggesting that DHMBA inhibits hyperactivity of the HPA axis. Nrf2 pathway activity induced by DHMBA resulted in increased antioxidant enzyme levels in the hippocampus

6-Gingerol activates the Nrf2 signaling pathway to alleviate hydrogen peroxide induced oxidative stress on primary chicken embryo hepatocytes

Oxidative stress affects production performance and meat quality of poultry. 6-gingerol (6-Gin) is the main activity component of ginger, has shown promise in alleviating oxidative stress in broilers, However, the specific protection mechanism of 6-Gin against hepatocytes oxidative damage remains unclear. The primary chicken embryo hepatocytes (CEHs) were damaged and the cell viability was decreased by H2O2, 6-Gin can alleviate the cell injure and oxidative stress. Transcriptomic analysis and further experiments showed that H2O2 significantly suppressed the expression of Nrf2, Keap1, and NQO1, as well as antioxidant enzyme activities, increased inflammatory factors, leading to cell apoptosis. In contrast, 6-Gin effectively reduced these effects by promoting Nrf 2 nuclear translocation and activating the Nrf2 signaling pathway. Furthermore, the protective effects of 6-Gin were eliminated by the Nrf2 inhibitor ML385. In conclusion, 6-Gin exerts antioxidant, anti-inflammatory and anti-apoptotic effects on CEHs through the Nrf2 pathway. This study provides the potential value of 6-Gin for treatment of oxidative stress in broilers.

Isoliquiritigenin alleviates cerebral ischemia-reperfusion injury by reducing oxidative stress and ameliorating mitochondrial dysfunction via activating the Nrf2 pathway

Cerebral ischemia-reperfusion injury (CIRI) refers to a secondary brain injury that occurs when blood supply is restored to ischemic brain tissue and is one of the leading causes of adult disability and mortality. Multiple pathological mechanisms are involved in the progression of CIRI, including neuronal oxidative stress and mitochondrial dysfunction. Isoliquiritigenin (ISL) has been preliminarily reported to have potential neuroprotective effects on rats subjected to cerebral ischemic insult. However, the protective mechanisms of ISL have not been elucidated. This study aims to further investigate the effects of ISL-mediated neuroprotection and elucidate the underlying molecular mechanism. The findings indicate that ISL treatment significantly alleviated middle cerebral artery occlusion (MCAO)-induced cerebral infarction, neurological deficits, histopathological damage, and neuronal apoptosis in mice. In vitro, ISL effectively mitigated the reduction of cell viability, Na+-K+-ATPase, and MnSOD activities, as well as the degree of DNA damage induced by oxygen-glucose deprivation (OGD) injury in PC12 cells. Mechanistic studies revealed that administration of ISL evidently improved redox homeostasis and restored mitochondrial function via inhibiting oxidative stress injury and ameliorating mitochondrial biogenesis, mitochondrial fusion-fission balance, and mitophagy. Moreover, ISL facilitated the dissociation of Keap1/Nrf2, enhanced the nuclear transfer of Nrf2, and promoted the binding activity of Nrf2 with ARE. Finally, ISL obviously inhibited neuronal apoptosis by activating the Nrf2 pathway and ameliorating mitochondrial dysfunction in mice. Nevertheless, Nrf2 inhibitor brusatol reversed the mitochondrial protective properties and anti-apoptotic effects of ISL both in vivo and in vitro. Overall, our findings revealed that ISL exhibited a profound neuroprotective effect on mice following CIRI insult by reducing oxidative stress and ameliorating mitochondrial dysfunction, which was closely related to the activation of the Nrf2 pathway.

PI3K/AKT signaling and neuroprotection in ischemic stroke: molecular mechanisms and therapeutic perspectives.

It has been reported that the PI3K/AKT signaling pathway plays a key role In the pathogenesis of ischemic stroke. As a result, the development of drugs targeting the PI3K/AKT signaling pathway has attracted increasing attention from researchers. This article reviews the pathological mechanisms and advancements in research related to the signaling pathways in ischemic stroke, with a focus on the PI3K/AKT signaling pathway.The key findings include the following: (1) The complex pathological mechanisms of ischemic stroke can be categorized into five major types: excitatory amino acid toxicity, Ca2+ overload, inflammatory response, oxidative stress, and apoptosis. (2) The PI3K/AKT-mediated signaling pathway is closely associated with the occurrence and progression of ischemic stroke, which primarily involves the NF-kB, NRF2, BCL-2, mTOR, and endothelial NOS signaling pathways. (3) Natural products, including flavonoids, quinones, alkaloids, phenylpropanoids, phenols, terpenoids, and iridoids, show great potential as candidate substances for the development of innovative anti-stroke medications. (4) Recently, novel therapeutic techniques, such as electroacupuncture and mesenchymal stem cell therapy, have demonstrated the potential to improve stroke outcomes by activating the PI3K/AKT signaling pathway, providing new possibilities for the treatment and rehabilitation of patients with ischemic stroke. Future investigations should focus on the direct regulatory mechanisms of drugs targeting the PI3K/AKT signaling pathway and their clinical translation to develop innovative treatment strategies for ischemic stroke.

Spatheliachromen mitigates methylglyoxal-induced myotube atrophy by activating Nrf2, inhibiting ubiquitin-mediated protein degradation, and restoring mitochondrial function

BackgroundMethylglyoxal (MGO) is a potent precursor of glycative stress that leads to oxidative stress and muscle atrophy in diabetes. Spatheliachromen (FPATM-20), derived from Ficus pumila var. awkeotsang, exhibited potential antioxidant activity. PurposeThis study aimed to evaluate the potential impact and underlying mechanisms of FPATM-20 on MGO-induced myotube atrophy and mitochondrial dysfunction in mouse skeletal C2C12 myotubes. MethodsAtrophic and antioxidant factors were evaluated using immunofluorescence, enzyme-linked immunosorbent assay, and western blotting. Mitochondrial function was assessed using the ATP assay and Seahorse Cell Mito Stress Test. The glycogen content was determined using periodic acid-Schiff staining. Molecular docking was performed to determine the interaction between FPATM-20 and Keap1. ResultsIn myotubes treated with MGO, FPATM-20 activated the Nrf2 pathway, reduced ROS levels, enhanced antioxidant defense, and increased glycogen content. FPATM-20 improved myotube viability and size, upregulated myosin heavy chain (MyHC) expression, modulated ubiquitin-proteasome molecules (nuclear FoxO3a, atrogin-1, MuRF-1, and p62/SQSTM1), and inhibited apoptosis (Bax/Bcl-2 ratio and cleaved caspase 3). Moreover, FPATM-20 restored mitochondrial function, including mitochondrial membrane potential, mitochondrial oxygen consumption rate, and mitochondrial biogenesis pathway (nuclear PGC-1α/TFAM/FNDC5). The inhibition of Nrf2 with ML385 reversed the effects of FPATM-20 on MGO. Furthermore, molecular docking confirmed the binding of FPATM-20 to Keap1, a suppressor of Nrf2, showing the crucial role of Nrf2 in protective effects. ConclusionsFPATM-20 protects myotubes from MGO toxicity by activating the Nrf2 antioxidant defense, reducing protein degradation and apoptosis, and enhancing mitochondrial function. Thus, FPATM-20 may be a novel agent for preventing skeletal muscle atrophy.

Increased NPM1 inhibit ferroptosis and aggravate renal fibrosis via Nrf2 pathway in chronic kidney disease

Recent findings underscore the significance of ferroptosis, an innovative iron-dependent mode of cell death, in the etiology and progression of chronic kidney disease (CKD). Nucleophosmin 1 (NPM1), a nucleolar protein, contributes to fibrogenesis and modulates cellular functions and mortality. Initial investigations utilized bioinformatics techniques to pinpoint genes with altered expression in CKD and to forecast the potential links between NPM1, ferroptosis, and renal fibrosis. Increased NPM1 expression was verified in the renal tissues of CKD patients. Experimental models of renal fibrosis in both animals and cells were then used for further study. The suppression of NPM1 led to an augmentation in iron metabolism and lipid peroxidation processes integral to ferroptosis, contributing to the mitigation of renal fibrosis. In contrast, an elevation in NPM1 expression had the opposite effect. This modulation may be interconnected with the nuclear factor erythroid 2–related factor 2 pathway. Moreover, the application of the ferroptosis inhibitor, Fer-1, not only obstructed ferroptosis but also diminished NPM1 expression, which, in turn, contributed to the alleviation of renal fibrosis. Thus, our findings suggest that in CKD the NPM1 level increased and led to decreased ferroptosis and aggravated renal fibrosis via an Nrf2 pathway. Ferroptosis inhibitor can alleviate renal fibrosis.

Activation of Nrf2 and FXR via Natural Compounds in Liver Inflammatory Disease.

Liver inflammation is frequently linked to oxidative stress and dysregulation of bile acid and fatty acid metabolism. This review focuses on the farnesoid X receptor (FXR), a critical regulator of bile acid homeostasis, and its interaction with the nuclear factor erythroid 2-related factor 2 (Nrf2), a key modulator of cellular defense against oxidative stress. The review explores the interplay between FXR and Nrf2 in liver inflammatory diseases, highlighting the potential therapeutic effects of natural FXR agonists. Specifically, compounds such as auraptene, cafestol, curcumin, fargesone A, hesperidin, lycopene, oleanolic acid, resveratrol, rutin, ursolic acid, and withaferin A are reviewed for their ability to modulate both the FXR and Nrf2 pathways. This article discusses their potential to alleviate liver inflammation, oxidative stress, and damage in diseases such as metabolic-associated fatty liver disease (MAFLD), cholestatic liver injury, and viral hepatitis. In addition, we address the molecular mechanisms driving liver inflammation, including oxidative stress, immune responses, and bile acid accumulation, while also summarizing relevant experimental models. This review emphasizes the promising therapeutic potential of targeting both the Nrf2 and FXR pathways using natural compounds, paving the way for future treatments for liver diseases. Finally, the limitations of the clinical application were indicated, and further research directions were proposed.

Advanced chelate technology-based trace minerals reduce inflammation and oxidative stress in Eimeria-infected broilers by modulating NF-kB and Nrf2 pathways

This study investigated the effects of substituting inorganic trace minerals (ITM) with advanced chelate technology-based TM (ACTM) in broiler chicken feed on productive performance, metabolic profile, humoral immunity, antioxidant status, and modulation of NF-kB and Nrf2 signaling pathways in mixed Eimeria species exposure. The study involved 480 newly hatched male broiler chickens, which were divided into 5 treatment groups, each with 6 replicate cages and 16 chickens per replicate. The experimental treatments included an uninfected negative control group fed a basal diet with recommended inorganic TM levels (NC), an infected positive control group fed the same diet (PC), a PC group supplemented with salinomycin (SAL), and two PC groups in which the basal diet was replaced with 50% and 100% ACTM instead of inorganic TM (ACTM50 and ACTM100, respectively). All groups, except for the NC group, were orally challenged with mixed Eimeria species oocysts on day 14. According to the results, the PC group showed lower feed intake, breast yield, low-density lipoprotein-cholesterol concentration, lactobacillus spp. counts, and serum IgG levels, but higher jejunal TGF-β expression versus the NC group. The broilers in the NC, SAL, and ACTM100 groups showed higher body weight gain, carcass yield, and TGF-β expression, but lower serum alkaline phosphatase activity, ileal E. coli count, and jejunal expression levels of IL-1β, IL-6, IFN-γ, Nrf2, and SOD1 compared to the PC group, with the NC group having the highest body weight gain and lowest IL-1β and Nrf2 expression levels. Furthermore, the administration of ACTM100 treatment improved feed efficiency, increased serum iron, zinc, manganese, and copper levels, enhanced total antioxidant capacity and different antioxidant enzyme activities, and reduced malondialdehyde concentration. In conclusion, complete replacement of ITM with ACTM effectively protects broilers from Eimeria infection, with similar positive effects to SAL treatment in terms of productive performance and anti-inflammatory responses and better antioxidant responses and mineral availability.

Effects of Nitric Oxide on Bladder Detrusor Overactivity through the NRF2 and HIF-1α Pathways: A Rat Model Induced by Metabolic Syndrome and Ovarian Hormone Deficiency.

Metabolic syndrome (MetS) includes cardiovascular risk factors like obesity, dyslipidemia, hypertension, and glucose intolerance, which increase the risk of overactive bladder (OAB), characterized by urgency, frequency, urge incontinence, and nocturia. Both MetS and ovarian hormone deficiency (OHD) are linked to bladder overactivity. Nitric oxide (NO) is known to reduce inflammation and promote healing but its effect on bladder overactivity in MetS and OHD is unclear. This study aimed to investigate NO's impact on detrusor muscle hyperactivity in rats with MetS and OHD. Female Sprague-Dawley rats were divided into seven groups based on diet and treatments involving L-arginine (NO precursor) and L-NAME (NOS inhibitor). After 12 months on a high-fat, high-sugar diet with or without OVX, a cystometrogram and tracing analysis of voiding behavior were used to identify the symptoms of detrusor hyperactivity. The MetS with or without OHD group had a worse bladder contractile response while L-arginine ameliorated bladder contractile function. In summary, MetS with or without OHD decreased NO production, reduced angiogenesis, and enhanced oxidative stress to cause bladder overactivity, mediated through the NF-kB signaling pathway, whereas L-arginine ameliorated the symptoms of detrusor overactivity and lessened oxidative damage via the NRF2/HIF-1α signaling pathway in MetS with or without OHD-induced OAB.

Tanshinone IIA inhibits H2O2-induced ferroptosis in melanocytes through activating Nrf2 signaling pathway.

Melanocyte ferroptosis has been proven to contribute to the development of vitiligo. Tanshinone IIA (TSA), a Chinese herbal extract, has been shown to inhibit vitiligo progression. Whether TSA regulates ferroptosis in melanocytes remains unclear. Hydrogen peroxide (H2O2) was used to induce melanocytes to stimulate vitiligo cell model in vitro. Cell proliferation was examined by 5-ethynyl-2'-deoxyuridine assay. The levels of malondialdehyde (MDA), reactive oxygen species (ROS), glutathione peroxidase (GSH) and iron (Fe2+) were detected by corresponding commercial kit. The protein levels of ferroptosis-related markers and Nrf2 pathway-related markers were examined using western blot and immunofluorescence staining. Cell viability and cytotoxicity were analyzed using cell counting kit 8 assay and lactate dehydrogenase (LDH) detection. Mitochondrial morphology was examined using a transmission electron microscope. After H2O2 treatment, melanocyte proliferation was reduced, while oxidative stress and ferroptosis were enhanced. TSA treatment could inhibit ferroptosis in H2O2-induced melanocytes. Besides, TSA could activate Nrf2 pathway and promote Nrf2 nuclear translocation, and Nrf2 specific inhibitor (ML385) also reversed the inhibitory effect of TSA on H2O2-induced melanocyte ferroptosis. Our data showed that TSA alleviated H2O2-induced melanocyte ferroptosis via activating Nrf2 pathway.

Identification of Astragalus Polysaccharide as a Neuroprotective Agent via Activating Klotho-mediated Nrf2 Pathway

Background Neurodegenerative diseases (NDs) have become a significant public health problem, and oxidative stress (OS) serves as a pivotal factor in the pathological progression of NDs. Pharmacological research indicates that Astragalus polysaccharide (APS, extract of Astragalus membranaceus) has antioxidant and antiaging effects, closely related to NDs. Purpose The potential of APS in treating NDs remains uncertain. Herein, the neuroprotective effect of APS was evaluated. Methods The H2O2-induced PC12 cell damage model was established to assess the neuroprotection of APS. Cell viability was determined by MTT. Cell images were observed using ImageXpress Micro Confocal analysis. Apoptosis of the cells and intracellular levels of reactive oxygen species (ROS) were detected using flow cytometry. The expression of Klotho, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), thioredoxin reductase 1 (TrxR1), and NAD(P)H quinone oxidoreductase 1 (NQO1) was determined by Western blot (WB). Results APS exerted significant protection against H2O2-caused cell death dose-dependently, and APS could significantly reduce the intracellular ROS and relieve cell apoptosis. Furthermore, we found that APS could upregulate the expression of Klotho and Nrf2 dose-dependently, and the expression levels of Nrf2-mediated antioxidant proteins increased significantly, including HO-1, TrxR1, and NQO1. Moreover, we found that APS upregulated Klotho and Nrf2-mediated antioxidant proteins time-dependently. The expression of klotho peaked at 6 hours after treatment with APS (400 mg/L). Subsequently, the protein level of Nrf2 reached the maximum at 12 hours, and the downstream NQO1, HO-1, and TrxR1 levels peaked at 24 hours. Conclusion This study demonstrates that APS is promising for further development against oxidative stress-related NDs.

High glucose- or AGE-induced oxidative stress inhibits hippocampal neuronal mitophagy through the Keap1–Nrf2–PHB2 pathway in diabetic encephalopathy

Diabetic encephalopathy (DE) is a severe complication of diabetes, but its pathogenesis remains unclear. This study aimed to investigate the roles and underlying mechanisms of high glucose (HG)- and advanced glycosylation end product (AGE)-induced oxidative stress (OS) in the cognitive decline in DE. The DE mouse model was established using a high-fat diet and streptozotocin, and its cognitive functions were evaluated using the Morris Water Maze, novel object recognition, and Y-maze test. The results revealed increased reactive oxygen species (ROS) generation, mitophagy inhibition, and decreased prohibitin 2 (PHB2) expression in the hippocampal neurons of DE mice and HG- or AGE-treated HT-22 cells. However, overexpression of PHB2 reduced ROS generation, reversed mitophagy inhibition, and improved mitochondrial function in the HG- or AGE-treated HT-22 cells and ameliorated cognitive decline, improved mitochondrial structural damage, and reversed mitophagy inhibition of hippocampal neurons in DE mice. Further analysis revealed that the Kelch-like ECH-associated protein 1 (Keap1)–nuclear factor erythroid 2-related factor 2 (Nrf2) pathway was involved in the HG- or AGE-mediated downregulation of PHB2 in HT-22 cells. These results demonstrate that HG- or AGE-induced OS inhibits the mitophagy of hippocampal neurons via the Keap1–Nrf2–PHB2 pathway, thereby contributing to the cognitive decline in DE.

Isothiocyanate-Rich Moringa Seed Extract Activates SKN-1/Nrf2 Pathway in Caenorhabditis elegans.

Moringa oleifera is a tropical tree that has its leaves, fruits, and seeds used as medicine and food. A standardized hydroalcoholic moringa seed extract (MSE) contains up to 40% of an isothiocyanate (MIC-1; moringin), a phytochemical known to have antioxidant and anti-inflammatory properties. Animal studies suggest that MSE may help with diseases, such as edema, colitis, obesity, and diabetes. In vitro studies have shown that MIC-1 activates the Nrf2 pathway, involved in detoxification and antioxidant pathways. To broaden the understanding of the molecular pathways regulated by MSE, we hypothesized that MSE improves the health span in Caenorhabditis elegans by activating the Nrf2 homolog (SKN-1). Our whole RNA-seq data showed that MSE at 0.1 mg/mL (100 µM MIC-1) regulated the expression of a total of 1555 genes, including genes related to C. elegans cuticle, molting cycle, and glutathione metabolism. MSE upregulated several glutathione S transferases (GST), involved in the detoxification of xenobiotics, and other SKN-1 downstream targets. MSE and MIC-1 upregulate skn-1 expression and induce SKN-1 nuclear translocation, suggesting that they activate the SKN-1/Nrf2 pathway. Moreover, the regulation of glutathione metabolism is likely dependent on the SKN-1 pathway, as the gst-4 upregulation by MSE was inhibited in skn-1 knockout mutant. However, MSE decreased survivability and delayed growth rate, while purified MIC-1 increased the lifespan of C. elegans. This study shows that MIC-1 is responsible for SKN-1/Nrf2 activation by MSE; however, components other than MIC-1 within MSE likely cause detrimental effects in C. elegans.

Exenatide improves cisplatin induced ovarian damage through NLRP3, Nrf-2, and TLR4 pathways.

Cisplatin (CP) toxicity causes ovarian damage by oxidative stress, inflammation and fibrosis. The aim of the present study is to investigate the possible beneficial effects of exenatide on the experimental ovarian damage model produced by CP. For 14 rats, CP was administered by intraperitoneally (i.p) twice a week for 5 weeks. No drug was administered to the remainder of rats (n = 7) (Group 0). The rats taken CP were divided into two groups. Group 1 rats (n = 7) were given 1 mL/kg/day saline i.p., and Group 2 rats (n = 7) was given with 20 μg/kg/day exenatide. The number of primordial, primary, secondary, and tertiary follicle was significantly lower in Group1 compared with Group 0 and Group 2. The ovarian fibrosis percent was significantly higher in Group 1 than Group 0 and 2. The plasma anti-Mullerian hormone value was lower in Group1compared with Group 0 and 2. Over Nuclear factor-erythroid factor 2-related factor 2 level, Over Toll-like receptor 4 level and over nucleotide-binding domain leucine-rich repeat and pyrin domain containing receptor 3 were higher in Group 1 compared with Group 0 and 2. Exenatide has possible beneficial effect on ovarian damage induced by CP by anti-inflammatory actions and can be a promising candidate for ovarian damage caused by CP.