Molecular Basis of the KEAP1-NRF2 Signaling Pathway

Sesquiterpene lactones from Cichorium intybus exhibit potent anti-inflammatory and hepatoprotective effects by repression of NF-κB and enhancement of NRF2

ETHNOPHARMACOLOGICAL RELEVANCE

Cichorium intybus is a traditional medicinal herb for hepatitis treatment in China and Europe. Sesquiterpene lactones are the main active ingredients in C. intybus. However, their structure-activity relationship (SAR) and molecular mechanisms of anti-inflammatory and hepatoprotective effects require further elucidation.

AIM OF THE STUDY

To identify new sesquiterpene lactones from C. intybus, and further evaluate their anti-inflammatory effects, SAR, and mechanisms of anti-inflammatory and hepatoprotective properties.

METHODS

Identification of sesquiterpene lactones from C. intybus using chromatographic fractionation, NMR, and mass spectrometry. The repression of inflammation was evaluated in RAW264.7 macrophages incubated with LPS. Western blotting was employed to investigate the anti-inflammatory mechanisms. The hepatoprotective effect was measured in LPS/D-galactosamine (D-GalN)-induced acute hepatitis in mice.

RESULTS

We identified 3 new sesquiterpene lactones and 15 known analogues from C. intybus. SAR analysis showed that the α-methylene-γ-lactone moiety was essential for their anti-inflammatory properties. Furthermore, 8-deoxylactucin was identified as the most potent anti-inflammatory component in LPS-induced RAW264.7 macrophages by reduction of nitric oxide production via inhibiting iNOS expression, and suppression of IL-1β, IL-6, and TNF-α expression. Mechanistically, 8-deoxylactucin not only blocked LPS-induced IKKα/β phosphorylation, IκBα phosphorylation and degradation, and NF-κB nuclear accumulation, but also enhanced NRF2 expression and nuclear translocation, HO-1 and NQO1 expression, and reduced ROS generation in vitro. In vivo, 8-deoxylactucin mitigated LPS/D-GalN-induced acute hepatitis, which manifested as reduction in inflammatory infiltration, live injury, serum levels of AST and ALT, and production of pro-inflammatory cytokines and 4-hydroxynonenal.

CONCLUSION

8-Deoxylactucin, the sesquiterpene lactone isolated from C. intybus, exerted anti-inflammatory and hepatoprotective effects by blocking NF-κB activation and enhancing NRF2 activation.

Targeting KEAP1-mediated IKKβ degradation strategy for colitis-associated colorectal carcinogenesis: The potential of xanthohumol

In colitis-associated colorectal cancer (CAC), the NF-κB pathway, especially IKKβ, drives inflammation and cancer progression. However, no IKKβ inhibitors have been approved due to compensatory mechanisms. The challenge is to develop an anti-tumor agent that effectively targets IKKβ while overcoming these compensatory pathways. We conducted in vitro and in vivo experiments to evaluate the anti-cancer effects of synthesized xanthohumol (XN) targeting IKKβ. CAC was induced in mice, followed by XN treatment. Histological and molecular analyses, including cell viability assays, immunoblotting, and qRT-PCR, were performed. Human colon cancer cell lines were also used to investigate IKKβ's role. RNA sequencing revealed elevated IKKβ expression in colorectal cancer human tissues, correlating with poor prognosis. XN significantly reduced adenocarcinoma formation and inflammation in vivo while decreasing IKKβ and NF-κB signaling in both models. XN binds to the C179 residue of IKKβ, inhibiting its activity. Additionally, our findings highlight KEAP1's role as an upstream regulator of IKKβ degradation. XN specifically interacts with the C288 residue of KEAP1, showing triple-binding affinity with IKKβ and KEAP1. These results indicate that XN promotes conditions where KEAP1 facilitates IKKβ degradation.

KEAP1-NRF2/HO-1 Pathway Promotes Ferroptosis and Neuronal Injury in Schizophrenia

BACKGROUND

This study investigates the role of the KEAP1-NRF2/HO-1 signaling pathway in inducing ferroptosis and contributing to neuronal damage in schizophrenia.

METHODS

We retrieved schizophrenia-related data and ferroptosis-related genes from the RNA microarray dataset GSE27383 and FerrDB database, respectively. Bioinformatics data identified KEAP1 as a downregulated gene, which was validated using qRT-PCR and Western blot. We assessed intracellular Fe2⁺ content, MDA levels, GSH, and GPX4 in the prefrontal cortex and peripheral blood mononuclear cells (PBMCs) of patients with schizophrenia. Cortical interneurons (cINs) were generated from human-induced pluripotent stem cells (hiPSCs) of patients with schizophrenia and used to explore KEAP1 alterations during neurodevelopment. In addition, KEAP1 overexpression was induced in cINs via transfection with pcDNA KEAP1. The intracellular Fe⁺ levels, oxidative stress indicators, lipid peroxidation, and inflammatory cytokines were measured after transfection. To investigate molecular mechanisms, KI696-a high-affinity probe that disrupts the KEAP1-NRF2 interaction-was applied, and changes in oxidative stress, lipid peroxidation (C11-BODIPY staining), iron metabolism, and inflammatory pathways were evaluated.

RESULTS

Patients with schizophrenia exhibited underexpression of KEAP1, a key regulator of ferroptosis, along with elevated intracellular Fe2⁺ levels and increased MDA concentrations, indicating enhanced lipid peroxidation and oxidative stress. Reduced GPX4 activity and GSH levels were also observed, suggesting an increased susceptibility to ferroptosis. To further explore this, cINs derived from hiPSCs of patients with schizophrenia were studied. These cells showed decreased KEAP1 expression. Overexpression of KEAP1 in cINs led to a reduction in intracellular Fe2⁺ concentrations and oxidative damage, highlighting KEAP1's regulatory role in ferroptosis. In addition, treatment with KI696 induced significant alterations in pathways related to oxidative stress, iron metabolism, antioxidant defenses, and inflammation.

CONCLUSION

Our findings indicate that the KEAP1-NRF2/HO-1 pathway contributes to ferroptosis and neuronal injury in schizophrenia.

Less is better: various means to reduce protein load in the endoplasmic reticulum

The endoplasmic reticulum (ER) is an important organelle that controls the intracellular and extracellular environments. The ER is responsible for folding almost one-third of the total protein population in the eukaryotic cell. Disruption of ER-protein folding is associated with numerous human diseases, including metabolic disorders, neurodegenerative diseases, and cancer. During ER perturbations, the cells deploy various mechanisms to increase the ER-folding capacity and reduce ER-protein load by minimizing the number of substrates entering the ER to regain homeostasis. These mechanisms include signaling pathways, degradation mechanisms, and other processes that mediate the reflux of ER content to the cytosol. In this review, we will discuss the recent discoveries of five different ER quality control mechanisms, including the unfolded protein response (UPR), ER-associated-degradation (ERAD), pre-emptive quality control, ER-phagy and ER to cytosol signaling (ERCYS). We will discuss the roles of these processes in decreasing ER-protein load and inter-mechanism crosstalk.

Immunotherapy for advanced-stage squamous cell lung cancer: the state of the art and outstanding questions

Immune-checkpoint inhibitors (ICIs) have transformed the treatment paradigm for advanced-stage squamous non-small-cell lung cancer (LUSC), a histological subtype associated with inferior outcomes compared with lung adenocarcinoma. However, only a subset of patients derive durable clinical benefit. In the first-line setting, multiple ICI regimens are available, including anti-PD-(L)1 antibodies as monotherapy, in combination with chemotherapy, or with an anti-CTLA4 antibody with or without chemotherapy. Several important questions persist regarding the optimal regimen for individual patients, particularly how to identify patients who might benefit from adding chemotherapy and/or anti-CTLA4 antibodies to anti-PD-(L)1 antibodies. An urgent need exists for predictive biomarkers beyond PD-L1 to better guide precision oncology approaches. Deeper knowledge of the underlying molecular biology of LUSC and its implications for response to ICIs will be important in this regard. Integration of this knowledge into multi-omics methods coupled with artificial intelligence might enable the development of more robust biomarkers. Finally, several novel therapeutic strategies, including novel ICIs, bispecific antibodies and personalized cancer vaccines, are emerging. Addressing these unresolved questions through innovative clinical trials and translational research will be crucial to further improving the outcomes of patients with LUSC. In this Review, we provide a comprehensive overview of current immunotherapeutic approaches, unresolved challenges and emerging strategies for patients with LUSC.

Arsenic and Chromium Induced Toxicity on Zebrafish Kidney: Mixture Effects on Oxidative Stress and Involvement of Nrf2-Keap1-ARE, DNA Repair, and Intrinsic Apoptotic Pathways

In polluted water, cooccurrences of two carcinogens, arsenic (As) and chromium (Cr), are extensively reported. Individual effects of these heavy metals have been reported in kidney of fishes, but underlying molecular mechanisms are not well established. There is no report on combined exposure of As and Cr in kidney. Thus, the present study investigated and compared individual and combined effects of As and Cr on zebrafish (Danio rerio) kidney treating at their environmentally relevant concentrations for 15, 30, and 60 days. Increased ROS levels, lipid peroxidation, GSH level, and decreased catalase activity implied oxidative stress in treated zebrafish kidney. Damage in histoarchitecture in treated groups was also noticed. The current study involved gene expression study of Nrf2, an important transcription factor of cellular stress responses along with its negative regulator Keap1 and downstream antioxidant genes nqo1 and ho1. Results indicated activation of Nrf2-Keap1 pathway after combined exposure. Expression pattern of ogg1, apex1, polb, and creb1 revealed the inhibition of base excision repair pathway in treatments. mRNA expression of tumor suppressor genes p53 and brca2 was also altered. Expressional alteration in bax, bcl2, caspase9, and caspase 3 indicated apoptosis (intrinsic pathway) induction, which was maximum in combined group. Inhibition of DNA repair and induction of apoptosis indicated that the activated antioxidant system was not enough to overcome the damage caused by As and Cr. Overall, this study revealed additive effects of As and Cr in zebrafish kidney after chronic exposure focusing cellular antioxidant and DNA damage responses.

The role of NRF2 function and regulation in atherosclerosis: an update

Atherosclerosis, a chronic inflammatory disease of the arteries, remains a leading cause of cardiovascular morbidity and mortality worldwide. This review examines the molecular mechanisms underlying NRF2 role in atherosclerosis, focusing on the recently defined intricate interplay between autophagy, the nuclear factor erythroid 2-related factor 2 (NRF2) pathway, microRNAs (miRNAs), and genes regulating NRF2 with atheroprotective effects. The NRF2/autophagy axis emerges as a critical regulator of cellular responses to oxidative stress and inflammation in atherosclerosis, with key players including Heat Shock Protein 90 (HSP90), Neuropeptide Y (NPY), and Glutaredoxin 2 (GLRX2). MiRNAs are identified as potent regulators of gene expression in atherosclerosis, impacting NRF2 signalling and disease susceptibility. Additionally, genes such as Prenyl diphosphate synthase subunit 2 (PDSS2), Sulfiredoxin1 (Srxn1), and Isocitrate dehydrogenase 1 (IDH1) are implicated in NRF2-dependent atheroprotective pathways. Future research directions include elucidating the complex interactions between these molecular pathways, evaluating novel therapeutic targets in preclinical and clinical settings, and addressing challenges related to drug delivery and patient heterogeneity. Despite limitations, this review underscores the potential for targeted interventions aimed at modulating NRF2/autophagy signalling and miRNA regulatory networks to mitigate atherosclerosis progression and improve cardiovascular outcomes.

Exposure to Selenomethionine and Selenocystine Induces Redox-Mediated ER Stress in Normal Breast Epithelial MCF-10A Cells

Selenium is an essential trace element co-translationally incorporated into selenoproteins with important biological functions. Health benefits have long been associated with selenium supplementation. However, cytotoxicity is observed upon excessive selenium intake. The aim of this study is to investigate the metabolic pathways underlying the response to the selenium-containing amino acids selenomethionine and selenocysteine in a normal human breast epithelial cell model. We show that both selenomethionine and selenocystine inhibit the proliferation of non-cancerous MCF-10A cells in the same concentration range as cancerous MCF-7 and Hela cells, which results in apoptotic cell death. Selenocystine exposure in MCF-10A cells caused a severe depletion of free low molecular weight thiols, which might explain the observed upregulation of the expression of the oxidative stress pathway transcription factor NRF2. Both selenomethionine and selenocystine induced the expression of target genes of the unfolded protein response (GRP78, ATF4, CHOP). Using a redox-sensitive fluorescent probe targeted to the endoplasmic reticulum (ER), we show that both selenoamino acids shifted the ER redox balance towards an even more oxidizing environment. These results suggest that alteration of the redox state of the ER may disrupt protein folding and cause ER stress-induced apoptosis in MCF-10A cells exposed to selenoamino acids.

Pyrimethamine and a potent analogue WCDD115 inhibit NRF2 by suppressing DHFR and one-carbon metabolism

Nuclear factor erythroid 2-related factor 2 (NFE2L2/NRF2) is a critical mediator of the cellular oxidative stress response. Aberrant activation of NRF2 is common in lung and upper aerodigestive cancers, where it promotes tumor initiation and progression and confers resistance to chemotherapy, radiation therapy, and immune checkpoint inhibitors. As such, NRF2 therapeutic inhibitors are actively being sought. We previously reported that the antiparasitic drug Pyrimethamine (PYR) inhibits NRF2 in cell lines and in a NRF2-inducible genetically engineered mouse model. Here we design, synthesize, and define structure-activity relationships across a series of 25 PYR-based derivatives to reveal WCDD115 as a 22-fold more potent inhibitor of NRF2 (57nM versus 1.2µM). PYR is known to inhibit plasmodial and human dihydrofolate reductase (DHFR). We found that WCDD115 inhibits hDHFR with 31-fold greater potency than PYR (144nM versus 4.49µM). Metabolomics showed strong similarities between PYR, WCDD115 and methotrexate. Genetic, pharmacological and metabolic epistasis studies reveal that DHFR inactivation is required for NRF2 suppression by WCDD115 and PYR. Global and targeted proteomics revealed overlapping profiles for WCDD115, PYR and methotrexate, including suppression of NRF2 oxidative stress response and activation of TP53 and the DNA damage response. Therefore, PYR and a novel potent derivative WCDD115 are effective, indirect inhibitors of NRF2 and its antioxidant functions. These data underscore the importance of one- carbon metabolism for the NRF2 signaling pathway and support a new therapeutic strategy to suppress NRF2-driven cancer biology.

Protection of Green Tea Polyphenols against Neurodegenerative Diseases: Evidence and Possible Mechanisms

Aging is a major risk factor for neurodegenerative diseases. With aging of the global population, the prevalence of neurodegenerative diseases, such as Alzheimer disease (AD) and Parkinson disease (PD), has increased worldwide. Unfortunately, the available therapeutic options for these neurodegenerative diseases are limited, most of which only provide symptomatic relief and have potentially serious side effects. Epidemiologic studies have shown that green tea consumption is associated with a lower prevalence of cognitive decline and decreased risk of AD and PD, providing an attractive preventive and therapeutic option. Polyphenols are major bioactive components in green tea, which contribute to the beneficial effects of green tea. Accumulating data suggest that green tea polyphenols (GTPs) have neuroprotective properties that inhibit the pathological development of neurodegenerative diseases; however, the underlying mechanisms are not yet completely understood. This paper reviews both in vitro and in vivo evidence that demonstrates the neuroprotective effects of GTPs against neurodegenerative diseases, with the main focus on AD and PD, and summarizes the possible molecular mechanisms by which GTPs impede the progression of neurodegeneration. In particular, this review highlights the modulation of GTPs on the common mechanisms involved in pathogenesis of neurodegenerative diseases, including oxidative stress-mediated neuronal toxicity, impaired proteostasis, and metal ion dyshomeostasis. The potential of using GTPs in the intervention of neurodegenerative diseases is also discussed, hopefully, providing useful insights into novel preventive and therapeutic strategies for these diseases.

Preliminary Data on the Senolytic Effects of Agrimonia pilosa Ledeb. Extract Containing Agrimols for Immunosenescence in Middle-Aged Humans: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Comparison Study

OBJECTIVES

To assess the effects of agrimol-containing Agrimonia pilosa Ledeb. extract (APE) for senescent immune cell removal in middle-aged Japanese adults with immunosenescence.

DESIGN AND SETTING

A randomized, double-blind, placebo-controlled, parallel-group study was conducted in Japan between June 2023 and April 2024.

PARTICIPANTS

110 individuals aged 40-59, selected based on CD8+ T cells with highly-expressing-senescence-associated-β-galactosidase (SA-βGal).

INTERVENTION

Participants were randomly assigned to receive 50 mg APE containing 0.2 mg of agrimols or a placebo for eight consecutive weeks.

MEASUREMENTS

The primary endpoint was the change in the proportion of CD8+ T cells with high SA-βGal expression at 8 weeks of intake from the baseline. The secondary endpoints included the proportion of CD4+ T cells with high SA-βGal expression, CD4+ and CD8+ T cell subsets, and the ratio of various immune cells.

RESULTS

Of the 635 subjects screened, 110 with immunosenescence were included in this study. In total, 55 participants in the placebo group and 53 in the APE group completed the intervention. There were no statistically significant changes in either the primary or secondary endpoints due to APE intake. In the male population, the proportion of CD8+ T cells with high SA-βGal expression was reduced by APE intake (p = 0.044). Furthermore, the proportion of naïve CD8+ T cells increased and the number of effector memory CD8+ T cells decreased with the consumption of APE.

CONCLUSIONS

APE was suggested to reduce senescent immune cells, indicating its potential as a candidate senolytic agent for humans; however, the results of this study are preliminary data, and further research on APE is needed (clinical trial registration: UMIN000051574).

Hyaluronic acid-curcumin nanoparticles for preventing the progression of experimental autoimmune uveitis through the Keap1/Nrf2/HO-1 signaling pathway

Globally, uveitis is a collection of intraocular inflammatory disorders that affect mainly the uvea, resulting in irreversible blindness and a heavy socioeconomic burden. Excessive autoimmune inflammation and oxidative stress are major drivers that contribute to the initiation and progression of uveitis. Nevertheless, current therapeutic methods for uveitis are limited and are accompanied by several serious adverse effects. Recently, nanotechnology-based antioxidant strategies have provided novel options for the treatment of ocular diseases. Although curcumin (CUR) has prominent antioxidant capacity and reactive oxygen species (ROS) scavenging ability, its low bioavailability and undetermined mechanisms limit its extensive application. This investigation demonstrated that esterified hyaluronic acid-curcumin nanoparticles (HA-CUR NPs) with superior aqueous dispersion exhibited exceptional antioxidant enzyme mimetic activity, incorporating superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), and free radical scavenging ability. Further in vitro and in vivo experimental results validated the protective function of HA-CUR NPs against oxidative stress-induced damage and inflammatory responses, attenuated pathological progression, relieved microvascular damage, and regulated fundus blood flow in retinal vascular networks. This may be attributable to the specific ability of HA-CUR NPs to target the CD44 receptor and activate the Keap1/Nrf2/HO-1 signaling pathway, suggesting a potential mechanism. In summary, this study revealed that HA-CUR NPs, which are composed of a natural product and biomacromolecules with outstanding artificial antioxidant enzyme activities, may be novel agents for effectively and safely treating uveitis and other ROS-related diseases.

Screening and Antioxidant Activities Evaluation of Peptides From Abalone (Haliotis discus hannai Ino)

Marine organisms are rich in antioxidant peptides; however, extracting these peptides is time-consuming, labor-intensive, and costly, with sequence losses leading to uncertain results. This study aimed to identify abalone-derived antioxidant peptides with strong Keap1 binding ability and validate their antioxidative activities using a cellular oxidative damage model. We constructed an abalone-derived peptide library comprising 363 peptides using virtual enzymatic hydrolysis techniques. Of the 98 human Keap1 protein structures available in the protein data bank database, 2FLU was selected as the receptor. Using the CDOCKER module in Discovery Studio software, molecular docking was performed with the peptide library as ligands and 2FLU as the receptor, targeting the binding site at coordinates x: 5.000222, y: 7.103889 and z: 5.058000. Ten abalone-derived peptides with the strongest inhibition against Keap1-Nrf2 interaction were identified. A 2,2'-azobis (2-methylpropionamidine) dihydrochloride (AAPH)-induced oxidative damage model in human umbilical vein endothelial cells (HUVECs) was used to verify the molecular docking results and identified DEDEDEDK as the most active antioxidant peptide. DEDEDEDK interferes with Keap1-Nrf2 binding, significantly reducing reactive oxygen species levels in damaged cells, increasing superoxide dismutase and catalase activities, and elevated glutathione content, indicating its potential to mitigate AAPH-induced oxidative damage in HUVECs.

Essential resources and best practices for laboratory mouse research

The laboratory mouse (Mus musculus) is the most widely used mammalian model organism in biomedical and life science research. This concise guide aims to provide essential information to assist researchers new to working with mice, covering topics such as mouse husbandry, maintenance, and available resources for obtaining mouse strains and associated data. Additionally, we discuss ethical considerations, emphasizing the 3Rs (replacement, reduction, and refinement) to ensure responsible and humane research practices.

Nrf2 Signaling Pathway: Focus on Oxidative Stress in Spinal Cord Injury

Spinal cord injury (SCI) is a serious, disabling injury to the central nervous system that can lead to motor, sensory, and autonomic dysfunction below the injury plane. SCI can be divided into primary injury and secondary injury according to its pathophysiological process. Primary injury is irreversible in most cases, while secondary injury is a dynamic regulatory process. Secondary injury involves a series of pathological events, such as ischemia, oxidative stress, inflammatory events, apoptotic pathways, and motor dysfunction. Among them, oxidative stress is an important pathological event of secondary injury. Oxidative stress causes a series of destructive events such as lipid peroxidation, DNA damage, inflammation, and cell death, which further worsens the microenvironment of the injured site and leads to neurological dysfunction. The nuclear factor erythrocyte 2-associated factor 2 (Nrf2) is considered to be a key pathway of antioxidative stress and is closely related to the pathological process of SCI. Activation of this pathway can effectively inhibit the oxidative stress process and promote the recovery of nerve function after SCI. Therefore, the Nrf2 pathway may be a potential therapeutic target for SCI. This review deeply analyzed the generation of oxidative stress in SCI, the role and mechanism of Nrf2 as the main regulator of antioxidant stress in SCI, and the influence of cross-talk between Nrf2 and related pathways that may be involved in the pathological regulation of SCI on oxidative stress, and summarized the drugs and other treatment methods based on Nrf2 pathway regulation. The objective of this paper is to provide evidence for the role of Nrf2 activation in SCI and to highlight the important role of Nrf2 in alleviating SCI by elucidating the mechanism, so as to provide a theoretical basis for targeting Nrf2 pathway as a therapy for SCI.

KEAP1-NRF2 Interaction in Cancer: Competitive Interactors and Their Role in Carcinogenesis

An American Cancer Society report estimates the emergence of around 2 million new cancer cases in the US in 2024 [...].

Dihydrotanshinone I Attenuates Diet-Induced Nonalcoholic Fatty Liver Disease via Up-Regulation of IRG1

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, but effective therapeutic drugs are still lacking. Dihydrotanshinone I (DHTS), a natural product isolated from Salvia miltiorrhiza, has been shown to have ameliorative effects on NAFLD. The aim of this study was to investigate the hepatoprotective effect of DHTS on NAFLD and its mechanism. A model of NAFLD and DHTS treatment was established using a Western diet to observe the effect of DHTS on NAFLD, which were detected by immunohistochemical, immunofluorescence, and other experiments. The mechanism was further explored by constructing immune responsive gene 1 (IRG1) knockout mice, RNA sequence, and molecular docking. The results revealed that DHTS significantly improved diet-induced metabolic disorders in mice, notably alleviating liver inflammation, oxidative stress, and fibrosis. Further analysis revealed that the intervention of DHTS was associated with the activation of IRG1. Subsequent experiments confirmed that IRG1 gene deletion reversed the above protective effects of DHTS in NAFLD. Mechanistically, DHTS enhanced the antioxidant nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway through IRG1/itaconate and blocked the oxidative stress response in the liver. In addition, DHTS also inhibited the activation of NACHT-, leucine-rich repeat (LRR)-, and pyrin domain (PYD)-containing protein 3 (NLRP3) inflammasome via IRG1/itaconate, blocking the inflammatory amplification effect in the liver. The study suggests that DHTS may be a potential drug for the treatment of NAFLD, which exerts protective regulatory effects mainly through the IRG1/itaconate molecular pathway.

From gut to liver: Exploring the crosstalk between gut-liver axis and oxidative stress in metabolic dysfunction-associated steatotic liver disease

Non-alcoholic fatty liver disease (NAFLD), now recognized as metabolic dysfunction-associated steatotic liver disease (MASLD), represents a significant and escalating global health challenge. Its prevalence is intricately linked to obesity, insulin resistance, and other components of the metabolic syndrome. As our comprehension of MASLD deepens, it has become evident that this condition extends beyond the liver, embodying a complex, multi-systemic disease with hepatic manifestations that mirror the broader metabolic landscape. This comprehensive review delves into the critical interplay between the gut-liver axis and oxidative stress, elucidating their pivotal roles in the etiology and progression of MASLD. Our analysis reveals several key findings: (1) Bile acid dysregulation can trigger oxidative stress through enhanced ROS production in hepatocytes and Kupffer cells, leading to mitochondrial dysfunction and lipid peroxidation; (2) Gut microbiota dysbiosis disrupts intestinal barrier function, allowing increased translocation of endotoxins like LPS, which activate inflammatory pathways through TLR4 signaling and promote oxidative stress via NADPH oxidase activation; (3) The redox-sensitive transcription factors NF-κB and Nrf2 serve as crucial mediators in the gut-liver axis, with NF-κB regulating inflammatory responses and Nrf2 orchestrating antioxidant defenses; (4) Oxidative stress-induced damage to intestinal barrier function creates a destructive feedback loop, further exacerbating liver inflammation and disease progression. These findings highlight the complex interrelationship between gut-liver axis dysfunction and oxidative stress in MASLD pathogenesis, suggesting potential therapeutic targets for disease management.

Integrating network pharmacology and experimental verification to reveal the ferroptosis-associated mechanism of Changpu-Yizhi-Wan in the treatment of Alzheimer's disease

To explore the pharmacological mechanism of Changpu-Yizhi-Wan (CYW) in the treatment of Alzheimer's disease (AD) from the perspective of ferroptosis based on network pharmacology and experimental verification. The Encyclopedia of Traditional Chinese Medicine 2.0 (ETCM2.0) database was used to collect the active components of CYW, and the putative targets were predicted in ETCM2.0 and SwissTargetPrediction database. The AD related targets were collected from GeneCards, comparative toxicogenomics database (CTD), Online Mendelian Inheritance in Man (OMIM), DisGeNET and Therapeutic Target Database (TTD), the ferroptosis related targets were collected from FerrDb V2 database, and the common targets of CYW, AD and ferroptosis were calculated by Venny2.1 platform. Protein-protein interaction (PPI) analysis was performed by STRING database, and the active compounds-target network and the PPI network were constructed using Cytoscape software. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome pathway enrichment analysis were performed through DAVID database. RSL3 was used to induce HT22 cells to establish a neuronal ferroptosis cell model, and the inhibitory effect of CYW on neuronal ferroptosis was evaluated by cell viability assay, intracellular iron assay and lipid peroxidation staining. The ferroptosis-associated key protein expressions of Nrf2, SLC7A11, GPX4 and FTH1 were detected by Western blot. A total of 100 candidate compounds were identified from CYW, and 1129 putative targets were obtained. 3924 AD-related targets and 564 ferroptosis-related targets were collected, respectively. There were 78 common targets between them and CYW targets, which were potential targets for CYW to regulate ferroptosis in the treatment of AD. PPI network analysis identified 10 key targets, including TP53, IL6, STAT3, HIF1A, NFE2L2, and others. GO, KEGG and Reactome enrichment analysis showed that 78 potential targets were involved in the regulation of ferroptosis and Nrf2-mediated gene transcription. Molecular docking showed that some active components of CYW had good affinity with Nrf2. In RSL3-induced HT22 cells, CYW significantly improved cell viability, reduced intracellular iron levels and inhibited lipid peroxidation, and improved the protein expression of Nrf2, SLC7A11, GPX4 and FTH1. The pharmacological mechanism of CYW in the treatment of AD may be related to the regulation of Nrf2/SLC7A11/GPX4/FTH1 axis to inhibit neuronal ferroptosis.

Nrf2 mediates mitochondrial and NADPH oxidase-derived ROS during mild heat stress at 40 °C

Hyperthermia is an adjuvant to chemotherapy and radiotherapy and sensitizes tumors to these treatments. However, repeated heat treatments result in acquisition of heat resistance (thermotolerance) in tumors. Thermotolerance is an adaptive survival response that appears to be mediated by upregulated cellular defenses. However, the mechanisms of activation remain unclear. When HeLa cells were exposed to mild heat shock at 40 °C for 3 h, levels of superoxide and peroxides increased. Cells were treated with mitochondrial antioxidant MitoQ and NADPH oxidase (NOX) inhibitor apocynin to characterize the contribution of these two sources to the total reactive oxygen species (ROS) pool. We found that both mitochondria and NOX are sources of ROS during mild heat shock at 40 °C. Heat-derived ROS are thought to activate the adaptive survival response at 40 °C. Nrf2, the master regulator of the cellular antioxidant response, is thought to play a pivotal role in establishing the adaptive survival response. Nrf2 was overexpressed or knocked down to assess its role. Moreover, Nrf2 levels correlate with the cellular redox state, and do so via scavenging of mitochondria- and NOX-derived ROS. Knockdown of Nrf2 markedly increased levels of ROS that were scavenged by either apocynin or MitoQ. Finally, critical defense proteins such as DJ-1 and PGAM5 seemed to require a two-key activation system mediated by Nrf2 and mitochondrial ROS. Our study characterized mitochondrial and NOX-derived ROS as being essential in activating cellular defenses alongside Nrf2 and underlines potential therapeutic targets that may contribute to the acquisition of thermotolerance.

Multi-defense pathways against electrophiles through adduct formation by low molecular weight substances with sulfur atoms

There is a variety of electrophiles in the environment. In addition, there are precursor chemicals that undergo metabolic activation by enzymes and conversion to electrophiles in the body. Although electrophiles covalently bind to protein nucleophiles, they also form adducts associated with adaptive or toxic responses. Low molecular weight compounds containing sulfur are capable of blocking such adduct formation by capturing the electrophiles. In this review, we present our findings on the capture and inactivation of electrophiles by: (i) intracellular glutathione, (ii) reactive sulfur species, and (iii) extracellular cysteine (formed during the production of sulfur adducts). These actions not only substantially suppress electrophilic activity but also regulate protein adduct formation.

Epigenetic Effects of Natural Products in Inflammatory Diseases: Recent Findings

Inflammation is an essential step for the etiology of multiple diseases. Clinically, due to the limitations of current drugs for the treatment of inflammatory diseases, such as serious side effects and expensive costs, it is urgent to explore novel mechanisms and medicines. Natural products have received extensive attention recently because of their multi-component and multi-target characteristics. Epigenetic modifications are crucial pathophysiological targets for developing innovative therapies for pharmacological interventions. Investigations examining how natural products improving inflammation through epigenetic modifications are emerging. This review state that natural products relieve inflammation via regulating the gene transcription levels through chromosome structure regulated by histone acetylation levels and the addition or deletion of methyl groups on DNA duplex. They could also exert anti-inflammatory effects by modulating the proteins in typical inflammatory signaling pathways by ubiquitin-related degradation and the effect of glycolysis derived free glycosyls. Studies on epigenetic modifications have the potential to facilitate the development of natural products as therapeutic agents. Future research directed at better understanding of how natural products modulate inflammatory processes through less studied epigenetic modifications including neddylation, SUMOylation, palmitoylation and lactylation, may provide new implications. Meanwhile, higher quality preclinical studies and more powerful clinical evidence are still needed to firmly establish the clinical efficacy of the natural products. Trial Registration: ClinicalTrials.gov Identifier: NCT01764204; ClinicalTrials.gov Identifier: NCT05845931; ClinicalTrials.gov Identifier: NCT04657926; ClinicalTrials.gov Identifier: NCT02330276.

Kelch-like ECH-associated Protein 1/Nuclear Factor Erythroid 2-related Factor 2 Pathway and Its Interplay with Oncogenes in Lung Tumorigenesis

Nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor regulating cellular redox homeostasis, exhibits a complex role in cancer biology. Genetic mutations in the Kelch-like ECH-associated protein 1 (KEAP1)/NRF2 system, which lead to NRF2 hyperactivation, are found in 20% to 30% of lung cancer cases. This review explores the intricate interplay between NRF2 and key oncogenic pathways in lung cancer, focusing on the interaction of KEAP1/NRF2 system with Kirsten rat sarcoma virus (KRAS), tumor protein P53 (TP53), epidermal growth factor receptor (EGFR), and phosphatidylinositol 3-kinases (PI3K)/AKT signaling. While NRF2 activation alone is insufficient to initiate tumorigenesis, it can significantly impact tumor initiation and progression when combined with oncogenic drivers such as KRAS. The review highlights the context-dependent effects of NRF2, from its protective role against chemical carcinogen-induced tumor initiation to its potential promotion of tumor growth in established cancers. These findings suggest the need for nuanced, stage-specific approaches to targeting the NRF2 pathway in cancer therapy.

Impacts of Copper Deficiency on Oxidative Stress and Immune Function in Mouse Spleen

INTRODUCTION

Copper is an essential trace element crucial for enzyme synthesis and metabolism. Adequate copper levels are beneficial for maintaining the normal immune function of the spleen. Copper deficiency disrupts the metabolic processes within the spleen and impairs its immune function. This research examines the impact of copper deficiency on the spleen and the potential recovery following copper supplementation.

METHODS

Weaned mice underwent a 4-week copper-deficient diet, succeeded by 1-week of copper repletion via intraperitoneal copper sulfate injection. Histological examination was used to assess pathological changes in the spleen. Biochemical assays were performed to measure oxidative stress levels in the spleen. ELISA, qPCR, and Western blot were employed to examine alterations in inflammatory markers, immune indicators, and oxidative regulatory factors across various levels.

RESULTS

Copper deficiency caused histological damage to the spleen, altered the expression of oxidative stress regulatory pathways (Nrf2, Keap1, and HO-1), and affected the expression of key inflammatory enzymes (iNOS, COX2) and transcription factor NF-κB, leading to oxidative damage. This was reflected by decreased levels of SOD, GSH, and T-AOC, along with increased levels of CAT and MDA. The levels of inflammatory cytokines IL-1β, TNF-α, IL-6, and IL-8 were notably increased. Copper supplementation significantly improved these changes.

CONCLUSIONS

Copper deficiency leads to spleen tissue damage in mice, affecting the Nrf2 regulatory pathway and inducing oxidative damage. Subsequent copper supplementation with copper sulfate effectively ameliorates the damage caused by copper deficiency.

Isolicoflavonol ameliorates acute liver injury via inhibiting NLRP3 inflammasome activation through boosting Nrf2 signaling in vitro and in vivo

BACKGROUND

NOD like receptor pyrin domain containing 3 (NLRP3) inflammasome is involved in innate immunity, and related to liver injury. However, no inflammasome inhibitors are clinically available until now. Our previous research suggests that isolicoflavonol (ILF), isolated from Macaranga indica, is a potent NLRP3 inflammasome inhibitor, but its mechanism is unclear.

METHODS

Fluorescent imaging and Western blot assay were used to ascertain the effects of ILF on pyroptosis and NLRP3 inflammasome activation in macrophages. Next, Nrf2 signal pathway, its downstream gene transcription and expression were further investigated. ML385, a Nrf2 inhibitor, was used to verify whether ILF targets Nrf2 signaling. A carbon tetrachloride induced liver injury model was introduced to evaluate the liver protection activity of ILF in mice.

RESULTS

This work revealed that ILF inhibited macrophage LDH release and IL-1β secretion in a dose-dependent manner. ILF had no significant cytotoxic effect on macrophage, it reduced pyroptosis and Gasdermin D N-terminal fragment formation. Moreover, ILF inhibited IL-1β maturation and Caspase-1 cleavage, but did not affect NLRP3, pro-Caspase-1, pro-IL-1β and ASC expression. ILF decreased ASC speck rate and reduced ASC oligomer formation. ILF decreased aggregated JC-1 formation restoring mitochondria membrane potential. In addition, ILF increased Nrf2 expression, extended Nrf2 lifespan and upregulated Nrf2 signaling pathway in macrophages whether the NLRP3 inflammasome was activated or not. Besides, ILF increased Nrf2 nuclear translocation, maintained a high proportion of Nrf2 in the nucleus, and upregulated ARE-related gene transcription and expression. Furthermore, Nrf2 signal inhibition attenuated compound ILF-mediated inhibition of pyroptosis, inflammasome activation and upregulation of Nrf2 signaling. ILF in a liver injury mouse model inhibited NLRP3 inflammasome activation and enhanced Nrf2 signaling.

CONCLUSION

Our study verified that ILF ameliorates liver injury via inhibiting NLRP3 inflammasome activation through boosting Nrf2 signaling, and highlighted that ILF is a potent anti-inflammatory drug for inflammasome-related liver diseases.

Adverse Effects of Nrf2 in Different Organs and the Related Diseases

Significance: Under normal physiological conditions, Nrf2 undergoes ubiquitination and subsequent proteasome degradation to maintain its basal activity. Oxidative stress can trigger Nrf2 activation, prompting its translocation to the nucleus where it functions as a transcription factor, activating various antioxidant pathways, and conferring antioxidant properties. Recent Advances: While extensive research has shown Nrf2's protective role in various diseases, emerging evidence suggests that Nrf2 activation can also produce harmful effects. Critical Issues: This review examines the pathological contexts in which Nrf2 assumes different roles, emphasizing the mechanisms and conditions that result in adverse outcomes. Future Directions: Persistent Nrf2 activation may have deleterious consequences, necessitating further investigation into the specific conditions and mechanisms through which Nrf2 exerts its harmful effects. Antioxid. Redox Signal. 00, 000-000.

Antibodies Against Anti-Oxidant Enzymes in Autoimmune Glomerulonephritis and in Antibody-Mediated Graft Rejection

Historically, oxidants have been considered mechanisms of glomerulonephritis, but a direct cause-effect correlation has never been demonstrated. Several findings in the experimental model of autoimmune conditions with renal manifestations point to the up-regulation of an oxidant/anti-oxidant system after the initial deposition of autoantibodies in glomeruli. Traces of oxidants in glomeruli cannot be directly measured for their rapid metabolism, while indirect proof of their implications is derived from the observation that Superoxide Oxidase 2 (SOD2) is generated by podocytes after autoimmune stress. The up-regulation of other anti-oxidant systems takes place as well. Here, we discuss the concept that a second wave of antibodies targeting SOD2 is generated in autoimmune glomerulonephritis and may negatively influence the clinical outcome. Circulating and renal deposits of anti-SOD2 antibodies have been detected in patients with membranous nephropathy and lupus nephritis, two main examples of autoimmune disease of the kidney, which correlate with the clinical outcome. The presence of anti-SOD2 antibodies in circulation and in the kidney has been interpreted as a mechanism which modifies the normal tissue response to oxidative stress. Overall, these findings repropose the role of the oxidant/anti-oxidant balance in autoimmune glomerulonephritis. The same conclusion on the oxidant/anti-oxidant balance may be proposed in renal transplant. Patients receiving a renal graft may develop antibodies specific for Glutathione Synthetase (GST), which modulates the amount of GST disposable for rapid scavenging of reactive oxygen species (ROS). The presence of anti-GST antibodies in serum is a major cause of rejection. The perspective is to utilize molecules with known anti-oxidant effects to modulate the anti-oxidative response in autoimmune pathology of the kidney. A lot of molecules with known anti-oxidant effects can be utilized, many of which have already been proven effective in animal models of autoimmune glomerulonephritis. Many molecules with anti-oxidant activity are natural products; in some cases, they are constituents of diets. Owing to the simplicity of these drugs and the absence of important adverse effects, many anti-oxidants could be directly utilized in human beings.

Reactive oxygen species: Janus-faced molecules in the era of modern cancer therapy

Oxidative stress, that is, an unbalanced increase in reactive oxygen species (ROS), contributes to tumor-induced immune suppression and limits the efficacy of immunotherapy. Cancer cells have inherently increased ROS production, intracellularly through metabolic perturbations and extracellularly through activation of NADPH oxidases, which promotes cancer progression. Further increased ROS production or impaired antioxidant systems, induced, for example, by chemotherapy or radiotherapy, can preferentially kill cancer cells over healthy cells. Inflammatory cell-derived ROS mediate immunosuppressive effects of myeloid-derived suppressor cells and activated granulocytes, hampering antitumor effector cells such as T cells and natural killer (NK) cells. Cancer therapies modulating ROS levels in tumors may thus have entirely different consequences when targeting cancer cells versus immune cells. Here we discuss the possibility of developing more efficient cancer therapies based on reduction-oxidation modulation, as either monotherapies or in combination with immunotherapy. Short-term, systemic administration of antioxidants or drugs blocking ROS production can boost the immune system and act in synergy with immunotherapy. However, prolonged use of antioxidants can instead enhance tumor progression. Alternatives to systemic antioxidant administration are under development where gene-modified or activated T cells and NK cells are shielded ex vivo against the harmful effects of ROS before the infusion to patients with cancer.

Specific cancer types and prognosis in patients with variations in the KEAP1-NRF2 system: A retrospective cohort study

The KEAP1-NRF2 system induces the expression of antioxidant genes in response to various types of oxidative stress. Some cancer cells activate this system, which increases their malignancy through genetic mutations. We performed a retrospective cohort study using the C-CAT database, which contains the gene-panel sequence data from 60,056 cases of diagnosed solid tumors. We analyzed somatic mutations in NRF2 and KEAP1 genes and their associations with clinical outcomes. Variants in the NRF2 gene were clustered in exon 2, which encodes the DLG and ETGE motifs essential for KEAP1 interaction. The NRF2 variants were frequently observed in esophageal and lung squamous cell carcinoma with frequencies of 35.9% and 19.6%, respectively. Among these mutations, the NRF2 variants in the ETGE motif were indicators of a worse prognosis. KEAP1 variants were found in 2.5% of all cases. The variants were frequent in lung cancer and showed a worse prognosis in lung and other types of adenocarcinomas. We then conducted gene expression analysis using TCGA data. While cancers with DLG and ETGE variants were similar in terms of gene expression profiles, there were significant differences between cancers with KEAP1 and NRF2 variants. Our results indicate that genetic alteration of the KEAP1-NRF2 pathway is a major factor in patient prognosis for each cancer type and its genetic variant. Variants in NRF2 and KEAP1 genes can characterize the biological basis of each cancer type and are involved in carcinogenesis, resistance to therapy, and other biological differences.

Praelolide alleviates collagen-induced arthritis through increasing catalase activity and activating Nrf2 pathway

BACKGROUND

Marine diterpenes represent a promising reservoir for identifying potential anti-rheumatoid arthritis (RA) candidates. Praelolide is a gorgonian-derived briarane-type diterpenoid with antioxidative and anti-osteoclastogenetic properties.

OBJECTIVE

This study aims to evaluate the therapeutic efficacy of praelolide against RA and investigate its underlying mechanisms both in vivo and in vitro.

METHOD

Collagen-induced arthritis (CIA) mice and human RA fibroblast-like synoviocyte MH7A cells were employed for bioassays. The VisuGait system was utilized to assess gait dysfunction resulting from joint pain. Histopathological changes in ankle and synovial tissues were evaluated using micro-computed tomography, hematoxylin and eosin staining, Safranin-O/Fast Green staining, tartrate resistant acid phosphatase staining, and immunohistochemistry. Fluorescence spectroscopy, circular dichroism, and surface plasmon resonance were employed to investigate interactions between praelolide and catalase. The production of inflammatory cytokines and expression levels of proteins were assessed using ELISA and Western blotting, respectively.

RESULT

Praelolide significantly reduced paw swelling and arthritis scores, improved gait deficits, and restored synovial histopathological alterations and bone erosion in CIA mice. In vivo and in vitro, praelolide effectively decreased the expression and production of inflammatory cytokines such as interleukin (IL)-1β and IL-6. Additionally, praelolide inhibited osteoclastogenesis on bone surface of the ankle joints and in a tumor necrosis factor-α (TNF-α)-induced MH7A/bone marrow-derived macrophages (BMMs) co-culture system, and it strongly suppressed reactive oxygen species (ROS) production. Mechanistically, praelolide modulated catalase through non-covalent interactions, inducing conformational alterations that enhanced catalase activity and stability against time- and temperature-induced degradation. Further investigation revealed that praelolide significantly upregulated the expression of Nrf2, subsequently activating downstream antioxidant enzymes.

CONCLUSION

Praelolide markedly alleviated synovial inflammation and bone destruction in CIA mice by enhancing catalase activity and activating the Nrf2 pathway to reduce disease-related ROS accumulation, highlighting praelolide as a promising candidate for multitarget treatment of RA.

Endogenous electrophiles and peroxymonocarbonate can link tyrosine phosphorylation cascades with the cytosolic TXNRD1 selenoprotein and the KEAP1/NRF2 system

Endogenously formed reactive molecules, such as lipid peroxides, 4-hydroxynonenal, methylglyoxal and other reactive oxygen species, can have major effects on cells. Accumulation of these molecules is counteracted by antioxidant enzymes, including the glutathione (GSH) and thioredoxin (Trx) systems, in turn regulated by the KEAP1/NRF2 system. Receptor tyrosine kinases (RTK) and their counteracting protein tyrosine phosphatases (PTP) are also modulated through redox regulation of PTP activities. The cytosolic selenoprotein thioredoxin reductase (TXNRD1) is particularly prone to attack at its easily accessible catalytic selenocysteine (Sec) residue by reactive electrophilic compounds. Therefore, we here discuss how endogenously formed electrophiles can modulate RTK/PTP signaling in a concentration- and time dependent manner by reactions either directly or indirectly linking TXNRD1 with the KEAP1/NRF2 system. Moreover, recent findings suggest that endogenous formation of peroxymonocarbonate can efficiently inhibit PTP activities and stimulate RTK signaling, seemingly bypassing PTP reduction as otherwise supported by the GSH/Trx systems.

Lactiplantibacillus plantarum JM113 alleviates deoxynivalenol induced intestinal damage by microbial modulation in broiler chickens

Deoxynivalenol (DON) contamination causes the grievous injury in public and animal health, poultry suffer from the greater toxin challenge. Probiotic have been considered as a potential way to mitigate the deleterious effects of DON. In this study, a total of 144 1-day-old Arbor Acres chickens were randomly assigned into 3 groups: control group, DON group (5 mg/kg DON diet), DJ group (1×109 cfu Lactiplantibacillus plantarum JM113/kg DON diet). The results showed that Lactiplantibacillus plantarum JM113 (L. plantarum JM113) increased the growth performance of 21-day-old broilers that challenged by the DON (P < 0.05), and the DON-induced disorder of jejunal morphology was recovered in DJ group (P < 0.05). Compared with the DON group, the mRNA and protein levels of Nrf2 and NQO-1 were upregulated in jejunum of DJ group broilers (P < 0.05). Meanwhile, administration of L. plantarum JM113 effectively increased the expression level of barrier-related genes, and the protein abundance of occludin and claudin1 (P < 0.05). L. plantarum JM113 restored the mRNA and protein abundance of PCNA, and proliferation-linked gene (Lgr5 and Bmi1) expression levels in jejunum of DON-insulted broilers (P < 0.05). Furthermore, administration of L. plantarum JM113 significantly enhanced the relative abundance of s_Limosilactobacillus_reuteri in jejuna of DON-challenged broilers (P < 0.05). Spearman correlation analysis showed that s_Limosilactobacillus_reuteri was positively associated with the jejunal barrier related genes (P < 0.05). In conclusion, L. plantarum JM113 alleviated the toxic effects of DON by regulating the jejunal function through microbial adjustment. Our findings proposed a viable approach to mitigating the adverse effects of deoxynivalenol exposure in broilers.

Esculin, a Coumarin Glucoside Prevents Fluoride-Induced Oxidative Stress and Cardiotoxicity in Zebrafish Larvae

Fluoride (F-) is a major groundwater contaminant spread across the world. In excess concentrations, F- can be detrimental to living beings. F- exposure is linked to cellular redox dyshomeostasis, leading to oxidative stress-mediated pathologies including heart dysfunction. Due to its potent antioxidant properties, various phytochemicals are found to alleviate the symptoms of F- toxicity. Hence, we explore the protective effect of esculin (Esc), a coumarin glucoside on F--induced oxidative stress and cardiotoxicity in zebrafish larvae. The experimental groups consisted of NaF (50 ppm) and Esc (100 μM) groups treated alone and in combination with a control group for 6 h. The groups were maintained till 78 hpf after which the level of oxidants (ROS, LPO, and PCC) and antioxidants (GST, GSH, GPx, SOD, and CAT) were assessed. The results revealed that Esc pretreatment restored the depleted antioxidant markers and reduced the levels of oxidant in the Esc+NaF group, exhibiting its antioxidant potential. In addition, analyses of the heartbeat rate and hemoglobin integrity using o-Dianisidine staining were conducted in the control and experimental groups. Esc treatment prevents F- induced cardiac changes including tachycardia and altered blood flow. Further, the mRNA expression level of antioxidant genes (nrf2, gstp1, hmox1a, prdx1, and nqo1) and cardiac developmental genes (bmp2b, nkx2.5, myh6, and myl7) confirmed that Esc acts as a potent free radical scavenger and antioxidant defense enhancer, protecting zebrafish larvae from NaF-induced oxidative stress and heart dysfunction.

Dynamic regulation of the oxidative stress response by the E3 ligase TRIP12

The oxidative stress response is centered on the transcription factor NRF2 and protects cells from reactive oxygen species (ROS). While ROS inhibit the E3 ligase CUL3 KEAP1 to stabilize NRF2 and elicit antioxidant gene expression, cells recovering from stress must rapidly reactivate CUL3 KEAP1 to prevent reductive stress and oxeiptosis-dependent cell death. How cells restore efficient NRF2-degradation upon ROS clearance remains poorly understood. Here, we identify TRIP12, an E3 ligase dysregulated in Clark-Baraitser Syndrome and Parkinson's Disease, as a component of the oxidative stress response. TRIP12 is a ubiquitin chain elongation factor that cooperates with CUL3 KEAP1 to ensure robust NRF2 degradation. In this manner, TRIP12 accelerates stress response silencing as ROS are being cleared, but limits NRF2 activation during stress. The need for dynamic control of NRF2-degradation therefore comes at the cost of diminished stress signaling, suggesting that TRIP12 inhibition could be used to treat degenerative pathologies characterized by ROS accumulation.

Effects of 1-Deoxynojirimycin Extracts of Mulberry Leaves on Oxidative Stress and the Function of the Intestinal Tract in Broilers Induced by H2O2

The poultry industry struggles with oxidative stress affecting gut health and productivity. This study examined using 1-Deoxynojirimycin (DNJ) extracts from mulberry leaves as an antioxidant in broilers feed to combat this issue. We divided 240 broilers, aged 16 days, into six groups, including a control and groups exposed to oxidative stress through H2O2 injections, with different supplement levels of DNJ-E (40, 80, 120, and 160 mg/kg of the basal diet) lasting until the broilers reached 42 days old. We evaluated intestinal morphology, ultrastructure, oxidative stress markers, the tight junction, and inflammatory cytokines. Adding 40 mg/kg DNJ-E improved villus height, the villus-to-crypt ratio, and cellular ultrastructure, and increased SOD levels in the jejunum and ileum, as well as CAT levels in the duodenum and jejunum (p < 0.05), compared to the H2O2 group. The addition of DNJ had differential effects on oxidative stress, the intestinal barrier, and immune-related genes. Importantly, the dosages of 40 mg/kg and 80 mg/kg resulted in an upregulation of MUC2 mRNA expression (p < 0.05). These findings suggest that DNJ-E holds potential as a beneficial feed additive for enhancing broiler health, particularly at supplementation levels below 80 mg/kg, as higher concentrations may negatively influence intestinal health. Future investigations should aim to elucidate the underlying mechanisms through which DNJ-E operates within the avian gastrointestinal system.

Nrf2 pathways in neuroprotection: Alleviating mitochondrial dysfunction and cognitive impairment in aging

Mitochondrial dysfunction and cognitive impairment are widespread phenomena among the elderly, being crucial factors that contribute to neurodegenerative diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important regulator of cellular defense systems, including that against oxidative stress. As such, increased Nrf2 activity may serve as a strategy to avert mitochondrial dysfunction and cognitive decline. Scientific data on Nrf2-mediated neuroprotection was collected from PubMed, Google Scholar, and Science Direct, specifically addressing mitochondrial dysfunction and cognitive impairment in older people. Search terms included "Nrf2", "mitochondrial dysfunction," "cognitive impairment," and "neuroprotection." Studies focusing on in vitro and in vivo models and clinical investigations were included to review Nrf2's therapeutic potential comprehensively. The relative studies have demonstrated that increased Nrf2 activity could improve mitochondrial performance, decrease oxidative pressure, and mitigate cognitive impairment. To a large extent, this is achieved through the modulation of critical cellular signalling pathways such as the Keap1/Nrf2 pathway, mitochondrial biogenesis, and neuroinflammatory responses. The present review summarizes the recent progress in comprehending the molecular mechanisms regarding the neuroprotective benefits mediated by Nrf2 through its substantial role against mitochondrial dysfunction and cognitive impairment. This review also emphasizes Nrf2-target pathways and their contribution to cognitive function improvement and rescue from mitochondria-related abnormalities as treatment strategies for neurodegenerative diseases that often affect elderly individuals.

Redox regulation of proteostasis

Oxidants produced through endogenous metabolism or encountered in the environment react directly with reactive sites in biological macromolecules. Many proteins, in particular, are susceptible to oxidative damage, which can lead to their altered structure and function. Such structural and functional changes trigger a cascade of events that influence key components of the proteostasis network. Here, we highlight recent advances in our understanding of how cells respond to the challenges of protein folding and metabolic alterations that occur during oxidative stress. Immediately after an oxidative insult, cells selectively block the translation of most new proteins and shift molecular chaperones from folding to a holding role to prevent wholesale protein aggregation. At the same time, adaptive responses in gene expression are induced, allowing for increased expression of antioxidant enzymes, enzymes that carry out the reduction of oxidized proteins, and molecular chaperones, all of which serve to mitigate oxidative damage and rebalance proteostasis. Likewise, concomitant activation of protein clearance mechanisms, namely proteasomal degradation and particular autophagic pathways, promotes the degradation of irreparably damaged proteins. As oxidative stress is associated with inflammation, aging, and numerous age-related disorders, the molecular events described herein are therefore major determinants of health and disease.

Regulation of NRF2 by Phosphoinositides and Small Heat Shock Proteins

Reactive oxygen species (ROS) are generated by aerobic metabolism, and their deleterious effects are buffered by the cellular antioxidant response, which prevents oxidative stress. The nuclear factor erythroid 2-related factor 2 (NRF2) is a master transcriptional regulator of the antioxidant response. Basal levels of NRF2 are kept low by ubiquitin-dependent degradation of NRF2 by E3 ligases, including the Kelch-like ECH-associated protein 1 (KEAP1). Here, we show that the stability and function of NRF2 is regulated by the type I phosphatidylinositol phosphate kinase γ (PIPKIγ), which binds NRF2 and transfers its product phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P 2 ) to NRF2. PtdIns(4,5)P 2 binding recruits the small heat shock protein HSP27 to the complex. Silencing PIPKIγ or HSP27 destabilizes NRF2, reduces expression of its target gene HO-1, and sensitizes cells to oxidative stress. These data demonstrate an unexpected role of phosphoinositides and HSP27 in regulating NRF2 and point to PIPKIγ and HSP27 as drug targets to destabilize NRF2 in cancer.

In brief

Phosphoinositides are coupled to NRF2 by PIPKIγ, and HSP27 is recruited and stabilizes NRF2, promoting stress-resistance.

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 OS and 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 levels and 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 dismutase 2 and 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.

Targeting NQO1 induces ferroptosis and triggers anti-tumor immunity in immunotherapy-resistant KEAP1-deficient cancers

Immunotherapy has revolutionized cancer treatment, yet the efficacy of immunotherapeutic approaches remains limited. Resistance to ferroptosis is one of the reasons for the poor therapeutic outcomes in tumors with Kelch-like ECH-associated protein 1 (KEAP1) mutations. However, the specific mechanisms by which KEAP1-mutant tumors resist immunotherapy are not fully understood. In this study, we showed that the loss of function in KEAP1 results in resistance to ferroptosis. We identified NAD(P)H Quinone Dehydrogenase 1 (NQO1) as a transcriptional target of nuclear factor erythroid 2-related factor 2 (NRF2) and revealed that inducing NQO1-mediated ferroptosis in KEAP1-deficient tumors triggers an antitumor immune cascade. Additionally, it was found that NQO1 protein levels could serve as a candidate biomarker for predicting sensitivity to immunotherapy in clinical tumor patients. We validated these findings in several preclinical tumor models. Overall, KEAP1 mutations define a unique disease phenotype, and targeting its key downstream molecule NQO1 offers new hope for patients with resistance to immunotherapy.

Sensor systems of KEAP1 uniquely detecting oxidative and electrophilic stresses separately In vivo

In the KEAP1-NRF2 stress response system, KEAP1 acts as a sensor for oxidative and electrophilic stresses through formation of S-S bond and C-S bond, respectively. Of the many questions left related to the sensor activity, following three appear important; whether these KEAP1 sensor systems are operating in vivo, whether oxidative and electrophilic stresses are sensed by the similar or distinct systems, and how KEAP1 equips highly sensitive mechanisms detecting oxidative and electrophilic stresses in vivo. To address these questions, we conducted a series of analyses utilizing KEAP1-cysteine substitution mutant mice, conditional selenocysteine-tRNA (Trsp) knockout mice, and human cohort whole genome sequence (WGS) data. Firstly, the Trsp-knockout provokes severe deficiency of selenoproteins and compensatory activation of NRF2. However, mice lacking homozygously a pair of critical oxidative stress sensor cysteine residues of KEAP1 fail to activate NRF2 in the Trsp-knockout livers. Secondly, this study provides evidence for the differential utilization of KEAP1 sensors for oxidative and electrophilic stresses in vivo. Thirdly, theoretical calculations show that the KEAP1 dimer equips quite sensitive sensor machinery in which modification of a single molecule of KEAP1 within the dimer is sufficient to affect the activity. WGS examinations of rare variants identified seven non-synonymous variants in the oxidative stress sensors in human KEAP1, while no variant was found in electrophilic sensor cysteine residues, supporting the fail-safe nature of the KEAP1 oxidative stress sensor activity. These results provide valuable information for our understanding how mammals respond to oxidative and electrophilic stresses efficiently.

Oxidative Stress and Inflammation in Myocardial Ischemia-Reperfusion Injury: Protective Effects of Plant-Derived Natural Active Compounds

Acute myocardial infarction (AMI) remains a leading cause of death among patients with cardiovascular diseases. Percutaneous coronary intervention (PCI) has been the preferred clinical treatment for AMI due to its safety and efficiency. However, research indicates that the rapid restoration of myocardial oxygen supply following PCI can lead to secondary myocardial injury, termed myocardial ischemia-reperfusion injury (MIRI), posing a grave threat to patient survival. Despite ongoing efforts, the mechanisms underlying MIRI are not yet fully elucidated. Among them, oxidative stress and inflammation stand out as critical pathophysiological mechanisms, playing significant roles in MIRI. Natural compounds have shown strong clinical therapeutic potential due to their high efficacy, availability, and low side effects. Many current studies indicate that natural compounds can mitigate MIRI by reducing oxidative stress and inflammatory responses. Therefore, this paper reviews the mechanisms of oxidative stress and inflammation during MIRI and the role of natural compounds in intervening in these processes, aiming to provide a basis and reference for future research and development of drugs for treating MIRI.

Autophagy Regulator Rufy 4 Promotes Osteoclastic Bone Resorption by Orchestrating Cytoskeletal Organization via Its RUN Domain

Rufy4, a protein belonging to the RUN and FYVE domain-containing protein family, participates in various cellular processes such as autophagy and intracellular trafficking. However, its role in osteoclast-mediated bone resorption remains uncertain. In this study, we investigated the expression and role of the Rufy4 gene in osteoclasts using small interfering RNA (siRNA) transfection and gene overexpression systems. Our findings revealed a significant increase in Rufy4 expression during osteoclast differentiation. Silencing Rufy4 enhanced osteoclast differentiation, intracellular cathepsin K levels, and formation of axial protrusive structures but suppressed bone resorption. Conversely, overexpressing wild-type Rufy4 in osteoclasts hindered differentiation while promoting podosome formation and bone resorption. Similarly, overexpression of a Rufy4 variant lacking the RUN domain mimics the effects of Rufy4 knockdown, significantly increasing intracellular cathepsin K levels, promoting osteoclastogenesis, and elongated axial protrusions formation, yet inhibiting bone resorption. These findings indicate that Rufy4 plays a critical role in osteoclast differentiation and bone resorption by regulating the cytoskeletal organization through its RUN domain. Our study provides new insights into the molecular mechanisms governing osteoclast activity and underscores Rufy4's potential as a novel therapeutic target for bone disorders characterized by excessive bone resorption.

ATF3 as a response factor to regulate Cd-induced reproductive damage by activating the NRF2/HO-1 ferroptosis pathway

Cadmium (Cd) has garnered significant attention due to reproductive toxicity in inducing ferroptosis. However, the specific mechanisms underlying Cd-induced germ cell ferroptosis remain poorly understood. This study aimed to systematically explore the molecular mechanisms of germ cell ferroptosis by investigating differential changes in transcription factors and proteins in male mice treated orally with CdCl2 (0.5 g/L) reaching postnatal day 60, alongside Leydig cell (TM3) and Sertoli cell (TM4) lines. Results demonstrated that Cd exposure led to increased iron overload and oxidative stress in mouse testes, disrupted intracellular mitochondrial morphology characteristic of ferroptosis. RNA sequencing revealed significant upregulation of Atf3 and Hmox1 in Cd-exposed germ cells, along with increased expression of ATF3 and HO-1. Intervention in ferroptosis or HO-1 effectively rescued cells from Cd-induced mortality by breaking the detrimental cycle between lipid peroxidation and HO-1 activation. Further findings showed that NRF2 and HO-1 expression was notably elevated upon ATF3 overexpression in TM3 and TM4 cells, activating the Keap1-Nrf2 pathway and triggering ferroptosis in testes, whereas NRF2 and HO-1 expression levels were reversed when ATF3 was silenced. This study provides novel insights into ATF3-mediated NRF2/HO-1 signaling in Cd-induced mitochondrial ferroptosis in testes, shedding light on the mechanisms underlying Cd-induced ferroptosis and testicular injury.

Role of oxidative stress in impaired type II diabetic bone repair: scope for antioxidant therapy intervention?

Impaired bone healing is a significant complication observed in individuals with type 2 diabetes mellitus (T2DM), leading to prolonged recovery, increased risk of complications, impaired quality of life, and increased risk of patient morbidity. Oxidative stress, resulting from an imbalance between the generation of reactive oxygen species (ROS) and cellular/tissue antioxidant defence mechanisms, has been identified as a critical contributor to the pathogenesis of impaired bone healing in T2DM. Antioxidants have shown promise in mitigating oxidative stress and promoting bone repair, particularly non-enzymic antioxidant entities. This comprehensive narrative review aims to explore the underlying mechanisms and intricate relationship between oxidative stress, impaired bone healing and T2DM, with a specific focus on the current preclinical and clinical evidence advocating the potential of antioxidant therapeutic interventions in improving bone healing outcomes in individuals with T2DM. From the ever-emerging evidence available, it is apparent that exogenously supplemented antioxidants, especially non-enzymic antioxidants, can ameliorate the detrimental effects of oxidative stress, inflammation, and impaired cellular function on bone healing processes during uncontrolled hyperglycaemia; and therefore, hold considerable promise as novel efficacious therapeutic entities. However, despite such conclusions, several important gaps in our knowledge remain to be addressed, including studies involving more sophisticated enzymic antioxidant-based delivery systems, further mechanistic studies into how these antioxidants exert their desirable reparative effects; and more extensive clinical trial studies into the optimisation of antioxidant therapy dosing, frequency, duration and their subsequent biodistribution and bioavailability. By enhancing our understanding of such crucial issues, we can fully exploit the oxidative stress-neutralising properties of these antioxidants to develop effective antioxidant interventions to mitigate impaired bone healing and reduce the associated complications in such T2DM patient populations.

Protective and Detoxifying Effects of Resveratrol on Zearalenone-Mediated Toxicity: A Review

Zearalenone (ZEA) is a mycotoxin produced by Fusarium spp. fungi and is widely found in moldy corn, wheat, barley, and other grains. ZEA is distributed to the whole body via blood circulation after metabolic transformation in animals. Through oxidative stress, immunosuppression, apoptosis, autophagy, and mitochondrial dysfunction, ZEA leads to hepatitis, neurodegenerative diseases, cancer, abortion, and stillbirth in female animals, and decreased sperm motility in male animals. In recent years, due to the influence of climate, storage facilities, and other factors, the problem of ZEA pollution in global food crops has become particularly prominent, resulting in serious problems for the animal husbandry and feed industries, and threatening human health. Resveratrol (RSV) is a natural product with therapeutic activities such as anti-inflammatory, antioxidant, and anticancer properties. RSV can alleviate ZEA-induced toxic effects by targeting signaling pathways such as NF-κB, Nrf2/Keap1, and PI3K/AKT/mTOR via attenuating oxidative damage, inflammatory response, and apoptosis, and regulating cellular autophagy. Therefore, this paper provides a review of the protective effect of RSV against ZEA-induced toxicity and its molecular mechanism, and discusses the safety and potential clinical applications of RSV in the search for natural mycotoxin detoxification agents.

The Role of Antioxidant Transcription Factor Nrf2 and Its Activating Compounds in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease in which kidney involvement, so-called lupus nephritis (LN), is common and one of the most severe manifestations. Oxidative stress (OS) may play a role in the pathogenesis of LN through the exacerbation of inflammation and immune cell dysfunction/dysregulation. Nuclear factor erythroid 2-related factor 2 (Nrf2), also known as nuclear factor erythroid-derived 2-like 2, is a transcription factor that in humans is encoded by the NFE2L2 gene and is regarded as a central regulator of the antioxidative response. Nrf2-activating compounds have been shown to alleviate oxidative stress in cells and tissues of lupus-prone mice. Although the precise mechanisms of Nrf2 activation on the immune system in SLE remain to be elucidated, Nrf2-activating compounds are considered novel therapeutical options to suppress OS and thereby might alleviate disease activity in SLE, especially in LN. This review therefore summarizes the role of the Nrf2 signaling pathway in the pathogenesis of SLE with LN and describes compounds modulating this pathway as potential additional clinical interventions.

NRF2 and Thioredoxin Reductase 1 as Modulators of Interactions between Zinc and Selenium

BACKGROUND

Selenium and zinc are essential trace elements known to regulate cellular processes including redox homeostasis. During inflammation, circulating selenium and zinc concentrations are reduced in parallel, but underlying mechanisms are unknown. Accordingly, we modulated the zinc and selenium supply of HepG2 cells to study their relationship.

METHODS

HepG2 cells were supplied with selenite in combination with a short- or long-term zinc treatment to investigate intracellular concentrations of selenium and zinc together with biomarkers describing their status. In addition, the activation of the redox-sensitive transcription factor NRF2 was analyzed.

RESULTS

Zinc not only increased the nuclear translocation of NRF2 after 2 to 6 h but also enhanced the intracellular selenium content after 72 h, when the cells were exposed to both trace elements. In parallel, the activity and expression of the selenoprotein thioredoxin reductase 1 (TXNRD1) increased, while the gene expression of other selenoproteins remained unaffected or was even downregulated. The zinc effects on the selenium concentration and TXNRD activity were reduced in cells with stable NRF2 knockdown in comparison to control cells.

CONCLUSIONS

This indicates a functional role of NRF2 in mediating the zinc/selenium crosstalk and provides an explanation for the observed unidirectional behavior of selenium and zinc.

NRF2 signaling and amino acid metabolism in cancer

Alterations in amino acid metabolism have emerged as a critical component in cancer biology, influencing various aspects of tumor initiation, progression, and metastasis. This review explores how amino acids, beyond their role as protein building blocks, are essential for redox balance, cell proliferation, metastasis, signaling/epigenetic regulation, and tumor microenvironment modulation in cancer. We particularly focus on the intricate relationship between amino acid metabolism and nuclear factor erythroid 2-related factor 2 (NRF2) signaling, a master regulator of oxidative stress response that frequently hyperactivated in cancer. Increasing evidence indicates that NRF2 is a key player in amino acid metabolism, orchestrating metabolism of cysteine, glutamine, and serine/glycine to promote cancer cell survival and growth. This comprehensive analysis provides insights into potential therapeutic strategies targeting the NRF2-amino acid metabolism axis, offering new avenues for cancer treatment that address multiple aspects of tumor biology.

Nattokinase as an adjuvant therapeutic strategy for non-communicable diseases: a review of fibrinolytic, antithrombotic, anti-inflammatory, and antioxidant effects

INTRODUCTION

Nattokinase (NK) is the primary ingredient of natto, a traditional Asian food made from fermented soybean by Bacillus subtilis natto. Studies have shown that natto reduces the risk of cardiovascular disease (CVD) mortality due to its fibrinolytic and antithrombotic properties. A new field of studies also demonstrates that NK can mitigate molecular pathways related to inflammation and oxidative stress and can be considered an adjuvant strategy for use in many non-communicable diseases (NCDs). This paper is a narrative review of the literature. A search was conducted in PubMed and ScienceDirect up to July 2024.

AREAS COVERED

This review discusses the possible effects of NK on mitigating the common complications of NCDs, such as inflammation and oxidative stress. In addition, it provides an update on the most addressed areas related to NK's fibrinolytic and antithrombotic activities.

EXPERT OPINION

Due to the fibrinolytic and antithrombotic activity of nattokinase, and more recently added to the anti-inflammatory and antioxidant effects, this enzyme can be used as a new adjuvant therapeutic strategy to mitigate inflammation and oxidative stress in NCDs, including CVD.