Nrf2 as regulator of innate immunity: A molecular Swiss army knife!

Ovalbumin alters DAF-16 Class-II/I gene expressions via insulin/insulin-like growth factor-1 signaling to initiate the innate immune response of Caenorhabditis elegans

Innate immunity, as a significant defense system of the body, plays a key role in allergic reactions, but the mechanism of how food allergens trigger innate immune signaling is still unclear. Ovalbumin (OVA) is a model allergen in food allergy studies. Previous studies by our group have demonstrated that the innate immunity of Caenorhabditis elegans (C. elegans) elicited by OVA treatment was related to the insulin/insulin-like growth factor-1 signaling (IIS) pathway, but the details remain unknown. Therefore, in this study, the molecular mechanism of innate immune signaling transduction of C. elegans stimulated by OVA was determined using genetic mutations as well as RT-PCR, GFP fluorescence visualization monitoring, and slow-killing experiments. Results showed that the expression levels of DAF-16-class-I/II genes in the IIS pathway were significantly changed in C. elegans after OVA treatment, and the upstream gene daf-2 played an important role, which up-regulated the levels of DAF-16-class-II genes dod-22 and F55G11.8 by the daf-2-pqm-1 pathway, and down-regulated the level of DAF-16-class-I gene thn-2 by the daf-2-daf-16 pathway. Moreover, the upstream genes daf-2 and nhr-14, and the transcription factors DAF-16, PQM-1, and SKN-1 in the IIS pathway all participated in the up-regulations of DAF-16-class-II genes dod-17, dod-24, and F55G11.2. In conclusion, details of OVA activating innate immunity in C. elegans through the IIS pathway are reported here, and the results can be further extrapolated to mammals, which will contribute to a better understanding of the mechanism of the occurrence of food allergic reactions from the perspective of innate immunity.

Crosstalk between ferroptosis and innate immune in diabetic kidney disease: mechanisms and therapeutic implications

Diabetic kidney disease (DKD) is a prevalent complication of diabetes mellitus (DM), and its incidence is increasing alongside the number of diabetes cases. Effective treatment and long-term management of DKD present significant challenges; thus, a deeper understanding of its pathogenesis is essential to address this issue. Chronic inflammation and abnormal cell death in the kidney closely associate with DKD development. Recently, there has been considerable attention focused on immune cell infiltration into renal tissues and its inflammatory response's role in disease progression. Concurrently, ferroptosis-a novel form of cell death-has emerged as a critical factor in DKD pathogenesis, leading to increased glomerular filtration permeability, proteinuria, tubular injury, interstitial fibrosis, and other pathological processes. The cardiorenal benefits of SGLT2 inhibitors (SGLT2-i) in DKD patients have been demonstrated through numerous large clinical trials. Moreover, further exploratory experiments indicate these drugs may ameliorate serum and urinary markers of inflammation, such as TNF-α, and inhibit ferroptosis in DKD models. Consequently, investigating the interplay between ferroptosis and innate immune and inflammatory responses in DKD is essential for guiding future drug development. This review presents an overview of ferroptosis within the context of DKD, beginning with its core mechanisms and delving into its potential roles in DKD progression. We will also analyze how aberrant innate immune cells, molecules, and signaling pathways contribute to disease progression. Finally, we discuss the interactions between ferroptosis and immune responses, as well as targeted therapeutic agents, based on current evidence. By analyzing the interplay between ferroptosis and innate immunity alongside its inflammatory responses in DKD, we aim to provide insights for clinical management and drug development in this area.

Identifying Baicalein as a Key Bioactive Compound in XueBiJing Targeting KEAP1: Implications for Antioxidant Effects

BACKGROUND

XueBiJing injection (XBJ) is renowned for its multi-target pharmacological effects, including immunomodulatory, antithrombotic, and antioxidant activities, offering potential therapeutic benefits for patients with severe infections such as sepsis and Coronavirus disease 2019 (COVID-19). Despite its clinical effectiveness, the molecular targets and mechanisms of XBJ remain unclear, warranting further investigation.

PURPOSE

This study aimed to identify the key bioactive compounds in XBJ and elucidate their molecular targets and mechanisms.

METHODS

The zebrafish model was first used to evaluate the anti-inflammatory and antioxidant effects of XBJ, and the differentially expressed genes (DEGs) were identified by RNA sequencing and network analysis. Network pharmacology was used to analyze the relationship between bioactive compounds and molecular targets, and molecular docking and kinetic simulation were used to explore the target binding ability of key compounds. Cellular Thermal Shift Assay-Western Blot (CETSA-WB) and Surface Plasmon Resonance (SPR) further verified the interaction between compounds and targets; finally, the key pathways were confirmed by gene silencing experiments.

RESULTS

The zebrafish model results reveal that XBJ significantly reduced neutrophil and macrophage counts in a dose-dependent manner, emphasizing its potent anti-inflammatory effects. A transcriptomic analysis highlighted the differential expression of key genes in the KEAP1/NRF2 pathway, including HMOX1, SLC7A11, NQO1, and TXNRD1. A network analysis further pinpointed KEAP1 as a central molecular target, with tanshinone IIA, baicalein, and luteolin identified as key active compounds modulating this pathway. Among these, tanshinone IIA and baicalein exhibited strong binding interactions with KEAP1, which were confirmed through molecular docking and kinetic simulations. Further validation showed that baicalein directly targets KEAP1, as demonstrated by CETSA-WB and SPR analysis. Additionally, the gene silencing experiments of KEAP1 and NRF2 reinforced their crucial roles in activating the KEAP1/NRF2 pathway.

CONCLUSION

These findings collectively establish baicalein as a critical bioactive compound in XBJ, driving its antioxidant and anti-inflammatory effects via KEAP1/NRF2 pathway activation through direct binding to KEAP1, providing new insights into the mechanism of action of XBJ.

Insights on the crosstalk among different cell death mechanisms

The phenomenon of cell death has garnered significant scientific attention in recent years, emerging as a pivotal area of research. Recently, novel modalities of cellular death and the intricate interplay between them have been unveiled, offering insights into the pathogenesis of various diseases. This comprehensive review delves into the intricate molecular mechanisms, inducers, and inhibitors of the underlying prevalent forms of cell death, including apoptosis, autophagy, ferroptosis, necroptosis, mitophagy, and pyroptosis. Moreover, it elucidates the crosstalk and interconnection among the key pathways or molecular entities associated with these pathways, thereby paving the way for the identification of novel therapeutic targets, disease management strategies, and drug repurposing.

Hyperoside attenuates sepsis-induced acute lung injury by Nrf2 activation and ferroptosis inhibition

Sepsis-induced acute lung injury (ALI) is a life-threatening condition associated with high morbidity and mortality rates in intensive care units (ICUs). Emerging evidence from clinical studies suggests that compounds derived from traditional Chinese medicine (TCM) have shown promising therapeutic effects in treating sepsis-induced ALI. Hyperoside is a bioactive compound extracted from TCM. Prior studies reported that hyperoside exhibits potent anti-inflammatory, antioxidant, and organ-protective properties, however, the underlying mechanisms of its effects on ALI remain unclear. Hyperoside pretreatment significantly reduced inflammation, iron accumulation, and lipid peroxidation in the pulmonary tissues of ALI mice induced by CLP and in LPS-stimulated MLE-12 cells. In particular, hyperoside preferentially binds with Keap1 at Arg380 and Arg415, thereby inhibiting the ubiquitin-mediated degradation of nuclear Nrf2, promoting its translocation to the nucleus, and leading to upregulation of anti-ferroptosis gene expression. Moreover, the protective effects of hyperoside were significantly abrogated after Nrf2 expression was silenced or its activity was inhibited by chemical inhibitors, highlighting that Nrf2 is critically involved in the impact of hyperoside. This study confirms that hyperoside exhibits a therapeutically protective effect against sepsis-induced ALI by inhibiting ferroptosis through Nrf2-mediated signaling pathway. Hyperoside acts as an Nrf2 activator by preferentially binding to Arg380 and Arg415 of Keap1 and disrupting the Keap1/Nrf2 interaction.

The influence of apigenin on cellular responses to radiation: From protection to sensitization

Apigenin, a dietary flavonoid, has gained increasing attention for its potential therapeutic applications in radiation protection and radiosensitization. Ionizing radiation (IR) can harm healthy cells, but as radiotherapy remains crucial in cancer treatment. Owing to the remarkable application of radiotherapy in the treatment of cancers, it is vital to protect healthy cells from radiation hazards while increasing the sensitivity of cancer cells to radiation. This article reviews the current understanding of apigenin's radioprotective and radiosensitive properties with a focuses on the involved signaling pathways and key molecular targets. When exposed to irradiation, apigenin reduces inflammation via cyclooxygenase-2 inhibition and modulates proapoptotic and antiapoptotic biomarkers. Apigenin's radical scavenging abilities and antioxidant enhancement mitigate oxidative DNA damage. It inhibits radiation-induced mammalian target of rapamycin activation, vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP), and STAT3 expression, while promoting AMPK, autophagy, and apoptosis, suggesting potential in cancer prevention. As a radiosensitizer, apigenin inhibits tumor growth by inducing apoptosis, suppressing VEGF-C, tumor necrosis factor alpha, and STAT3, reducing MMP-2/9 activity, and inhibiting cancer cell glucose uptake. Cellular and animal studies support apigenin's radioprotective and anticancer potential, making it a potential candidate for further research. Investigation into apigenin's therapeutic efficacy in diverse cancer types and radiation damage is essential.

Protective Effects of Capsaicinoid Glucoside from Fresh Hot Peppers Against Hydrogen peroxide-induced Oxidative Stress in HepG2 Cells Through-dependent Signaling Pathway

This study aimed to investigate the protective effect of a novel capsaicinoid glucoside (CG) against H2O2-induced oxidative stress in HepG2 cells and elucidate its underlying molecular mechanism. CG treatment significantly reduced H2O2-induced cell mortality and attenuated the production of lactate dehydrogenase and malondialdehyde in a dose-dependent manner. Moreover, CG drastically reduced the ROS levels 18.7, 37.4, and 43.8% at concentrations of 25, 50, and 100 µg/mL, respectively. while increased glutathione content and catalase activity. Most importantly, in silico analysis revealed that CG effectively interacted with each of TRPV1 and Nrf2 by H-bonds, π-π interactions, and hydrophobic forces without simulation fluctuations over 50 ns. TRP, LYS, THR, LEU, GLN, VAL, ILE, and TYR residues of the tested proteins were all involved in the interaction with CG. These findings suggested that CG could reduce H2O2-induced oxidative stress in HepG2 cells via TRPV1/Nrf2 pathway which could be validated in functional foods/supplements formulations.

The Dynamic Role of Curcumin in Mitigating Human Illnesses: Recent Advances in Therapeutic Applications

Herbal medicine, particularly in developing regions, remains highly popular due to its cost-effectiveness, accessibility, and minimal risk of adverse effects. Curcuma longa L., commonly known as turmeric, exemplifies such herbal remedies with its extensive history of culinary and medicinal applications across Asia for thousands of years. Traditionally utilized as a dye, flavoring, and in cultural rituals, turmeric has also been employed to treat a spectrum of medical conditions, including inflammatory, bacterial, and fungal infections, jaundice, tumors, and ulcers. Building on this longstanding use, contemporary biochemical and clinical research has identified curcumin-the primary active compound in turmeric-as possessing significant therapeutic potential. This review hypothesizes that curcumin's antioxidant properties are pivotal in preventing and treating chronic inflammatory diseases, which are often precursors to more severe conditions, such as cancer, and neurological disorders, like Parkinson's and Alzheimer's disease. Additionally, while curcumin demonstrates a favorable safety profile, its anticoagulant effects warrant cautious application. This article synthesizes recent studies to elucidate the molecular mechanisms underlying curcumin's actions and evaluates its therapeutic efficacy in various human illnesses, including cancer, inflammatory bowel disease, osteoarthritis, atherosclerosis, peptic ulcers, COVID-19, psoriasis, vitiligo, and depression. By integrating diverse research findings, this review aims to provide a comprehensive perspective on curcumin's role in modern medicine and its potential as a multifaceted therapeutic agent.

Deciphering the Liaison Between Fine Particulate Matter Pollution, Oxidative Stress, and Prostate Cancer: Where Are We Now?

Prostate cancer (PCa), a highly prevalent cancer in men worldwide, is projected to rise in the coming years. As emerging data indicate the carcinogenic effects of fine particulate matter (PM2.5) in lung cancer and other site-specific cancers, there is an urgent need to evaluate the relationship between this environmental risk factor and PCa as a potential target for intervention. The present review provides up-to-date evidence about the impact of airborne PM2.5 pollution on the initiation and progression of PCa. Examining the composition and characteristics of PM2.5 reveals its ability to induce toxic effects, inflammatory injuries, and oxidative damages. Additionally, PM2.5 can attach to endocrine-disrupting chemicals implicated in prostatic carcinogenesis. Considering the potential significance of oxidative stress in the risk of the disease, our review underlines the protective strategies, such as antioxidant-based approaches, for individuals exposed to increased PM2.5 levels. Moreover, the findings call for further research to understand the associations and mechanisms linking PM2.5 exposure to PCa risk as well as to suggest appropriate measures by policymakers, scientific researchers, and healthcare professionals in order to address this global health issue.

Naturally-derived modulators of the Nrf2 pathway and their roles in the intervention of diseases

Cumulative evidence has verified that persistent oxidative stress is involved in the development of various chronic diseases, including pulmonary, neurodegenerative, kidney, cardiovascular, and liver diseases, as well as cancers. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a pivotal role in regulating cellular oxidative stress and inflammatory reactions, making it a focal point for disease prevention and treatment strategies. Natural products are essential resources for discovering leading molecules for new drug research and development. In this review, we comprehensively outlined the progression of the knowledge on the Nrf2 pathway, Nrf2 activators in clinical trials, the naturally-derived Nrf2 modulators (particularly from 2014-present), as well as their effects on the pathogenesis of chronic diseases.

Landscape of targeted therapies for lung squamous cell carcinoma

Lung cancer, a common type of malignant neoplasm, has seen significant advancements in the treatment of lung adenocarcinoma (LUAD). However, the management of lung squamous cell carcinoma (LSCC) continues to pose challenges. Traditional treatment methods for LSCC encompass surgical resection, chemotherapy, and radiotherapy. The introduction of targeted therapy and immunotherapy has greatly benefited LSCC patients, but issues such as limited immune response rates and adverse reactions persist. Therefore, gaining a deeper comprehension of the underlying mechanisms holds immense importance. This review provides an in-depth overview of classical signaling pathways and therapeutic targets, including the PI3K signaling pathway, CDK4/6 pathway, FGFR1 pathway and EGFR pathway. Additionally, we delve into alternative signaling pathways and potential targets that could offer new therapeutic avenues for LSCC. Lastly, we summarize the latest advancements in targeted therapy combined with immune checkpoint blockade (ICB) therapy for LSCC and discuss the prospects and challenges in this field.

Nrf2-mediated ferroptosis inhibition: a novel approach for managing inflammatory diseases

Inflammatory diseases, including psoriasis, atherosclerosis, rheumatoid arthritis, and ulcerative colitis, are characterized by persistent inflammation. Moreover, the existing treatments for inflammatory diseases only provide temporary relief by controlling symptoms, and treatments of unstable and expensive. Therefore, new therapeutic solutions are urgently needed to address the underlying causes or symptoms of inflammatory diseases. Inflammation frequently coincides with a high level of (reactive oxygen species) ROS activation, serving as a fundamental element in numerous physiological and pathological phenotypes that can result in serious harm to the organism. Given its pivotal role in inflammation, oxidative stress, and ferroptosis, ROS represents a focal node for investigating the (nuclear factor E2-related factor 2) Nrf2 pathway and ferroptosis, both of which are intricately linked to ROS. Ferroptosis is mainly triggered by oxidative stress and involves iron-dependent lipid peroxidation. The transcription factor Nrf2 targets several genes within the ferroptosis pathway. Recent studies have shown that Nrf2 plays a significant role in three key ferroptosis-related routes, including the synthesis and metabolism of glutathione/glutathione peroxidase 4, iron metabolism, and lipid processes. As a result, ferroptosis-related treatments for inflammatory diseases have attracted much attention. Moreover, drugs targeting Nrf2 can be used to manage inflammatory conditions. This review aimed to assess ferroptosis regulation mechanism and the role of Nrf2 in ferroptosis inhibition. Therefore, this review article may provide the basis for more research regarding the treatment of inflammatory diseases through Nrf2-inhibited ferroptosis.

The toxic effect of lead exposure on the physiological homeostasis of grouper: Insight from gut-liver axis

The heavy metal lead (Pb) pollution in marine environment has been widely concerned. The liver and intestine are important for the health of fish. In this study, the grouper were exposed to 1 μg/L Pb for 14 days, and the physiological homeostasis changes were explored via gut-liver axis. The results showed that Pb stress caused liver morphological changes, oxidative stress, and the accumulation and peroxidation of the lipids. The liver metabolism were disturbed, especially amino acid metabolism and the synthesis and degradation of ketone bodies. Pb stress also caused intestinal mucosal ablation, tight junction dysfunction and inflammatory response. Additionally, intestinal microbial diversity was decreased, and the community composition was altered especially several bacteria genera (Ruminococcus UCG-005, Ruminococcus UCG-014, Oscillibacter, and Streptococcus) were significantly correlated with the physiological indexes and metabolites of the liver. These results reveal that Pb stress negatively affect the physiological homeostasis of the grouper via gut-liver axis.

Ovalbumin promotes innate immune response of Caenorhabditis elegans through DAF-16 and SKN-1 pathways in insulin/IGF-1 signaling

Ovalbumin (OVA) is a major allergen in eggs and could induce severe allergic reactions in sensitive individuals, where the innate immune system works as a regulator. The mechanism of how innate immunity adjusts to food allergy is relatively well-studied, however, the effects of allergen uptake on the innate immune system remain unclear. Therefore, the Caenorhabditis elegans (C. elegans) model was utilized to assess the effects of OVA on its innate immune system. OVA enhanced the immune response of C. elegans with higher survival rates under Pseudomonas aeruginosa infection. Moreover, sustaining OVA treatment improved the health states that were reflected in the prolonged lifespan, alleviated oxidative stress, accelerated growth, and promoted motility. RNA-sequencing analysis and the slow-killing assays in the mutants of insulin/IGF-1 signaling (IIS)-related genes confirmed that IIS was necessary for OVA to regulate innate immunity. Besides, OVA activated SKN-1 temporarily and facilitated the nuclear localization of DAF-16 for improving immunity and health status in C. elegans. Together, OVA could enhance the innate immune responses via DAF-16 and SKN-1 pathways in the IIS of C. elegans, and this work will provide novel insights into the regulation of innate immunity by OVA in higher organisms.

Transcription factor NF-E2-related factor 2 plays a critical role in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) by regulating ferroptosis

NRF2 is an important transcription factor that regulates redox homeostasis in vivo and exerts its anti-oxidative stress and anti-inflammatory response by binding to the ARE to activate and regulate the transcription of downstream protective protein genes, reducing the release of reactive oxygen species. Ferroptosis is a novel iron-dependent, lipid peroxidation-driven cell death mode, and recent studies have shown that ferroptosis is closely associated with acute lung injury/acute respiratory distress syndrome (ALI/ARDS). NRF2 is able to regulate ferroptosis through the regulation of the transcription of its target genes to ameliorate ALI/ARDS. Therefore, This article focuses on how NRF2 plays a role in ALI/ARDS by regulating ferroptosis. We further reviewed the literature and deeply analyzed the signaling pathways related to ferroptosis which were regulated by NRF2. Additionally, we sorted out the chemical molecules targeting NRF2 that are effective for ALI/ARDS. This review provides a relevant theoretical basis for further research on this theory and the prevention and treatment of ALI/ARDS. The intended audience is clinicians and researchers in the field of respiratory disease.

The toxic effects of tetracycline exposure on the physiological homeostasis of the gut-liver axis in grouper

Antibiotic residues, such as tetracycline (TET), in aquatic environments have become a global concern. The liver and gut are important for immunity and metabolism in aquatic organisms. In this study, juvenile groupers were subjected to 1 and 100 μg/L TET for 14 days, and the physiological changes of these fish were evaluated from the perspective of gut-liver axis. After TET exposure, the liver showed histopathology, lipid accumulation, and the elevated ALT activity. An oxidative stress response was induced in the liver and the metabolic pattern was disturbed, especially pyrimidine metabolism. Further, intestinal health was also affected, including the damaged intestinal mucosa, the decreased mRNA expression levels of tight junction proteins (ZO-1, Occludin, and Claudin-3), along with the increased gene expression levels of inflammation (IL-1β, IL-8, TNF-α) and apoptosis (Casp-3 and p53). The diversity of intestinal microbes increased and the community composition was altered, and several beneficial bacteria (Lactobacillus, Bacteroidales S24-7 group, and Romboutsia) and harmful (Aeromonas, Flavobacterium, and Nautella) exhibited notable correlations with hepatic physiological indicators and metabolites. These results suggested that TET exposure can adversely affect the physiological homeostasis of groupers through the gut-liver axis.

Antiviral, anti-inflammatory and antioxidant effects of curcumin and curcuminoids in SH-SY5Y cells infected by SARS-CoV-2

COVID-19, caused by SARS-CoV-2, affects neuronal cells, causing several symptoms such as memory loss, anosmia and brain inflammation. Curcuminoids (Me08 e Me23) and curcumin (CUR) are derived from Curcuma Longa extract (EXT). Many therapeutic actions have been linked to these compounds, including antiviral action. Given the severe implications of COVID-19, especially within the central nervous system, our study aims to shed light on the therapeutic potential of curcuminoids against SARS-CoV-2 infection, particularly in neuronal cells. Here, we investigated the effects of CUR, EXT, Me08 and Me23 in human neuroblastoma SH-SY5Y. We observed that Me23 significantly decreased the expression of plasma membrane-associated transmembrane protease serine 2 (TMPRSS2) and TMPRSS11D, consequently mitigating the elevated ROS levels induced by SARS-CoV-2. Furthermore, Me23 exhibited antioxidative properties by increasing NRF2 gene expression and restoring NQO1 activity following SARS-CoV-2 infection. Both Me08 and Me23 effectively reduced SARS-CoV-2 replication in SH-SY5Y cells overexpressing ACE2 (SH-ACE2). Additionally, all of these compounds demonstrated the ability to decrease proinflammatory cytokines such as IL-6, TNF-α, and IL-17, while Me08 specifically reduced INF-γ levels. Our findings suggest that curcuminoid Me23 could serve as a potential agent for mitigating the impact of COVID-19, particularly within the context of central nervous system involvement.

Context-dependent antioxidant defense system (ADS)-based stress memory in response to recurrent environmental challenges in congeneric invasive species

Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities, imposing pressures on marine species. To withstand recurring environmental challenges, marine organisms, especially benthic species lacking behavioral choices to select optimal habitats, have to utilize well-established strategies such as the antioxidant defense system (ADS) to ensure their survival. Therefore, understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges. Here we conducted a comparative analysis of the physiological and transcriptional responses based on the ADS during two rounds of 'hypersalinity-recovery' challenges in two model congeneric invasive ascidians, Ciona robusta and C. savignyi. Our results demonstrated that C. savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level, while C. robusta demonstrated heightened responses at the transcriptional level. We observed distinct transcriptional responses, particularly in the utilization of two superoxide dismutase (SOD) isoforms. Both Ciona species developed physiological stress memory with elevated total SOD (T-SOD) and glutathione (GSH) responses, while only C. robusta demonstrated transcriptional stress memory. The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species. These findings support the 'context-dependent stress memory hypothesis', emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges. Our results enhance our understanding of the mechanisms of environmental challenge management in marine species, particularly those related to the ADS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-024-00228-y.

Interleukin-17 alleviates erastin-induced alveolar bone loss by suppressing ferroptosis via interaction between NRF2 and p-STAT3

AIM

To investigate the relationship between interleukin-17 (IL-17), ferroptosis and osteogenic differentiation.

MATERIALS AND METHODS

We first analysed the changes in ferroptosis-related molecules in experimental periodontitis models. The effects of erastin, a small-molecule ferroptosis inducer, and IL-17 on alveolar bone loss and repair in animal models were then investigated. Primary mouse mandibular osteoblasts were exposed to erastin and IL-17 in vitro. Ferroptosis- and osteogenesis-related genes and proteins were detected. Further, siRNA, immunofluorescence co-localization and immunoprecipitation were used to confirm the roles of the nuclear factor erythroid-2-related factor 2 (NRF2) and phosphorylated signal transducer and activator of transcription 3 (p-STAT3), as well as their interaction.

RESULTS

The levels of NRF2, glutathione peroxidase 4 and solute carrier family 7 member 11 were lower in the ligated tissues than in normal periodontal tissues. Alveolar bone loss in an in vivo experimental periodontitis model was aggravated by erastin and alleviated by IL-17. In vitro, IL-17 ameliorated erastin-inhibited osteogenic differentiation by reversing ferroptosis. Altered NRF2 expression correlated with changes in ferroptosis-related molecules and osteogenesis. Furthermore, the physical interaction between NRF2 and p-STAT3 was confirmed in the nucleus. In IL-17 + erastin-stimulated osteoblasts, the p-STAT3-NRF2 complex might actively participate in the downstream transcription of ferroptosis- and osteogenesis-related genes.

CONCLUSIONS

IL-17 administration conferred resistance to erastin-induced osteoblast ferroptosis and osteogenesis. The possible mechanism may involve p-STAT3 directly interacting with NRF2.

Toxic effects of three variants of microcystins on the intestinal histology, physiological and metabolic response of Litopenaeus vannamei

Microcystins (MCs) are harmful substances to the health of cultured shrimp, and there are many variants of MCs. Intestinal is the immune and metabolic center of the shrimp, and is also the target organ for MCs toxicity. In this study, the shrimp Litopenaeus vannamei juvenile were separately exposed to 1 μg/L of three MCs variants (LR, YR, RR) for 72 h respectively, and the changes of intestinal morphology, physiological response and metabolic function were analyzed. The results showed the three MCs variants stress caused intestinal mucosal damage and disordered the homeostasis of antimicrobial genes (ALF and Lys) expression. The mRNA expression levels of antioxidant genes (Nrf2 and GPx) and apoptosis factors (CytC and Casp-3) were increased, but that of detoxification gene (CYP450) was decreased. Furthermore, the intestinal metabolic pattern was also influenced by stresses, among which MC-LR induced more differential metabolites than that of MC-YR and MC-RR. The function of purine metabolism was highly influenced by the stress of three MCs variants, followed by amino acid metabolism, but there were differences in the types of amino acids. The metabolites citric acid, L-glutamine, L-tryptophan, spermine, UMP, and indole contributed to the metabolic pathway network. Nineteen stress-related metabolites were identified as candidates for subsequent screening of potential biomarkers. These results revealed the toxic effects of three MCs variants on the intestinal physiological and metabolic homeostasis of the shrimp.

The adverse impacts of ammonia stress on the homeostasis of intestinal health in Pacific white shrimp (Litopenaeus vannamei)

Ammonia is a prevalent pollutant in aquaculture systems that poses a risk to shrimp health. The shrimp's intestine plays a crucial role in immunity and metabolism. Therefore, we exposed Litopenaeus vannamei to 2 mg/L ammonia-N stress for a duration of 7 days, and explored the alterations in intestinal tissue morphology, physiological status, microbial community, and metabolic function. The findings revealed that ammonia stress led to a decrease in shrimp survival rates and inflicted damage to the intestinal mucosa, resulting in epithelial exfoliation. The mRNA relative expression levels of oxidative stress genes (Nrf2 and SOD) were elevated, while the level of GPx was decreased. Additionally, there was an increase in the levels of endoplasmic reticulum stress genes (Bip, IRE1 and XBP1), inflammatory cytokines (NF-κB and JNK), and apoptosis mediators (CytC and Casp-3) were increased. Ammonia stress also caused a decline in intestinal microbial diversity and significant variations in the bacterial community composition, including Bacteroides, Enterococcus, Faecalibacterium, Nautella, Pseudoalteromonas, Tenacibaculum, and Weissella. Furthermore, ammonia stress disrupted the intestinal metabolic function, particularly affecting pyrimidine, purine, amino acid, and alkaloid metabolism. These results revealed that 2 mg/L ammonia-N stress damaged the intestinal health of the shrimp by damaging mucosal integrity, affecting physiological homeostasis, causing microbial community and metabolic variation, which are related to the decreased survival of the shrimp and should be paid attention to in shrimp farming.

Carrot Juice Intake Affects the Cytokine and Chemokine Response in Human Blood after Ex Vivo Lipopolysaccharide-Induced Inflammation

In vitro and animal studies have shown that carrot juice containing bioactive natural products, such as falcarinol (FaOH) and falcarindiol (FaDOH), can affect inflammation. The present study was designed to test whether oral intake of carrot juice containing the bioactive acetylenic oxylipins FaOH and FaDOH affects mediators of acute inflammation or the innate immune response in human blood. Carrot juice (500 mL) was administered orally to healthy volunteers, and blood samples were drawn before and 1 h after juice intake. Next, the blood samples were split in two, and one sample was stimulated ex vivo with lipopolysaccharide (LPS) and incubated at 37 °C for 24 h. The concentrations of 44 inflammatory cytokines and chemokines were examined using multiplex electrochemiluminescence analysis. In blood samples not stimulated with LPS, a significant increase in IL-15 was measured 1 h after carrot juice intake. Cytokines like IFN-ɣ, IL-12/IL-23(p40), IL-23, IL-17A, IL-17B, IL-17D, and IL-22 were significantly increased in LPS-stimulated blood samples after carrot juice intake. The upregulation of the immunostimulating cytokines belonging to the IL-23/IL-17 Th17 axis suggests that carrot juice intake could benefit diseases where inflammation plays a role, like in the early stages of diabetes or cancers.

The role of MOTS-c-mediated antioxidant defense in aerobic exercise alleviating diabetic myocardial injury

Myocardial remodeling and dysfunction are commonly observed in type 2 diabetes mellitus (T2DM). Aerobic exercise can partly alleviate diabetes-induced myocardial dysfunction through its antioxidant actions. MOTS-c is a potential exercise mimic. This study aimed to investigate the effects of MOTS-c on improving diabetic heart function and its mechanism and to identify whether MOTS-c improved antioxidant defenses due to aerobic exercise. Herein, we established a rat model of T2DM induced by high-fat diet combined with a low-dose streptozotocin injection. Interventions were performed using intraperitoneal injections of MOTS-c (i.p. 0.5 mg/kg/day, 7 days/week) or aerobic exercise training (treadmill, 20 m/min, 60 min/day, 5 days/week) for 8 weeks. Myocardial ultrastructure was assessed using transmission electron microscopy (TEM), myocardial lipid peroxidation levels (MDA), superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT) levels were assessed using colorimetric methods, and molecular analyses including MOTS-c, Kelch-like ECH-associated protein 1 (Keap1), Nuclear factor E2-related factor 2 (Nrf2), adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)and phospho-AMPK (p-AMPK) were examined using Western blot. The results showed that MOTS-c, with or without exercise, reduced myocardial ultrastructural damage and improved glucolipid metabolism and cardiac function in T2DM. Furthermore, MOTS-c increased antioxidant markers such as SOD, CAT, and the protein expression of myocardial MOTS-c, Keap1, Nrf2, and p-AMPK. MOTS-c with exercise treatment reduced myocardial MDA and increased p-AMPK significantly comparing to only exercise or MOTS-c alone. Our findings suggest that MOTS-c may be a helpful supplement for overcoming exercise insufficiency and improving myocardial structure and function in diabetes.

A state-of-the-art review on the NRF2 in Hepatitis virus-associated liver cancer

According to a paper released and submitted to WHO by IARC scientists, there would be 905,700 new cases of liver cancer diagnosed globally in 2020, with 830,200 deaths expected as a direct result. Hepatitis B virus (HBV) hepatitis C virus (HCV), and hepatitis D virus (HDV) all play critical roles in the pathogenesis of hepatocellular carcinoma (HCC), despite the rising prevalence of HCC due to non-infectious causes. Liver cirrhosis and HCC are devastating consequences of HBV and HCV infections, which are widespread worldwide. Associated with a high mortality rate, these infections cause about 1.3 million deaths annually and are the primary cause of HCC globally. In addition to causing insertional mutations due to viral gene integration, epigenetic alterations and inducing chronic immunological dysfunction are all methods by which these viruses turn hepatocytes into cancerous ones. While expanding our knowledge of the illness, identifying these pathways also give possibilities for novel diagnostic and treatment methods. Nuclear factor erythroid 2-related factor 2 (NRF2) activation is gaining popularity as a treatment option for oxidative stress (OS), inflammation, and metabolic abnormalities. Numerous studies have shown that elevated Nrf2 expression is linked to HCC, providing more evidence that Nrf2 is a critical factor in HCC. This aberrant Nrf2 signaling drives cell proliferation, initiates angiogenesis and invasion, and imparts drug resistance. As a result, this master regulator may be a promising treatment target for HCC. In addition, the activation of Nrf2 is a common viral effect that contributes to the pathogenesis, development, and chronicity of virus infection. However, certain viruses suppress Nrf2 activity, which is helpful to the virus in maintaining cellular homeostasis. In this paper, we discussed the influence of Nrf2 deregulation on the viral life cycle and the pathogenesis associated with HBV and HCV. We summed up the mechanisms for the modulation of Nrf2 that are deregulated by these viruses. Moreover, we describe the molecular mechanism by which Nrf2 is modulated in liver cancer, liver cancer stem cells (LCSCs), and liver cancer caused by HBV and HCV. Video Abstract.

The Role of Ozone as an Nrf2-Keap1-ARE Activator in the Anti-Microbial Activity and Immunity Modulation of Infected Wounds

Ozone is an allotrope of oxygen, widely known to exert an anti-oxidant potential. The ability of low, controlled and standardized doses of ozone in the ozone adjunct treatment of bacterial infections, which occur in wounds, is engaging clinical research to deepen the role of ozone in eradicating even multidrug-resistant bacteria. Ozone activates the nuclear factor erythroid 2-related factor 2 (Nrf2), and this activation triggers a complex cascade of events, which ultimately leads to macrophage training and an improvement in their ability to operate a clearance of bacteria in the patient's anatomical districts. In this review, we try to elucidate the recent evidence about the mechanisms with which ozone can actually remove bacteria and even multi-drug-resistant (MDR) bacteria, accounting on its complex ability in modulating immunity.

Amelioration Effects and Regulatory Mechanisms of Different Tea Active Ingredients on DSS-Induced Colitis

The potential biological function of tea and its active components on colitis has attracted wide attention. In this study, different tea active ingredients including tea polyphenols (TPPs), tea polysaccharides (TPSs), theabrownin (TB), and theanine (TA) have been compared in the intervention of dextran sulfate sodium (DSS)-induced colitis in mice. Specifically, TPP showed the greatest effect on colitis since it reduced 60.87% of disease activity index (DAI) compared to that of the DSS-induced colitis group, followed by the reduction of 39.13% of TPS and 28.26% of TB on DAI, whereas there was no obvious alleviative effect of TA on colitis. TPP, TPS, and TB could regulate the composition and abundance of gut microbiota to increase the content of short-chain fatty acids (SCFAs) and enhance intestinal barrier function. Further evidence was observed that TPP and TPS regulated the activation of Nrf2/ARE and the TLR4/MyD88/NF-κB P65 pathway to alleviate the colitis. Results of cell experiments demonstrated that TPP showed the greatest antiapoptosis and mitochondrial function protective capability among the tea ingredients via inhibiting the Cytc/Cleaved-caspase-3 signaling pathway. In summary, the superior anticolitis activity of TPP compared to TPS and TB is primarily attributed to its unique upregulation of the abundance of Akkermansia and its ability to regulate the mitochondrial function.

SARS-CoV-2 infection and dysregulation of nuclear factor erythroid-2-related factor 2 (Nrf2) pathway

Coronavirus disease 2019 (COVID-19) is a recent pandemic caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) leading to pulmonary and extra-pulmonary manifestations due to the development of oxidative stress (OS) and hyperinflammation. The underlying cause for OS and hyperinflammation in COVID-19 may be related to the inhibition of nuclear factor erythroid 2-related factor 2 (Nrf2), a master regulator of antioxidative responses and cellular homeostasis. The Nrf2 pathway inhibits the expression of pro-inflammatory cytokines and the development of cytokine storm and OS in COVID-19. Nrf2 activators can attenuate endothelial dysfunction (ED), renin-angiotensin system (RAS) dysregulation, immune thrombosis, and coagulopathy. Hence, this review aimed to reveal the potential role of the Nrf2 pathway and its activators in the management of COVID-19. As well, we tried to revise the mechanistic role of the Nrf2 pathway in COVID-19.

Screening of genes encoding proteins that interact with Nrf2: Probing a cDNA library from Mytilus coruscus using a yeast two-hybrid system

The Nuclear factor Erythroid 2-related factor 2 (Nrf2) is the most important endogenous antioxidant factor in organisms, and it has been demonstrated that it exerts extensive control over the immune response by interacting with crucial innate immunity components directly or indirectly. Although Nrf2 has been widely confirmed to be involved in stress resistance in mammals and some fish, its contribution to mollusks oxidative stress resistance has not frequently been documented. In this investigation, total RNA was taken from the digestive gland of M. coruscus, and a cDNA library was constructed and screened using the GATEWAY recombination technology. The Nrf2 cDNA sequence of M. coruscus was cloned into the pGBKT7 vector to prepare the bait plasmid. Using yeast two-hybrid system, after auxotrophic medium screening, sequencing, and bioinformatics analysis, 13 binding proteins that interacted with Nrf2 were finally identified. They were QM-like protein, 40S ribosomal protein S4 (RPS4), ribosomal protein S2 (RPS2), ribosomal protein L12 (RPL12), EF1-alpha mRNA for elongation factor 1 alpha (eEF1-alpha), ferritin, alpha-amylase, trypsin, vdg3, period clock protein, cyclophilin A isoform 1 (CYP A), serine protease CFSP2, histone variant H2A.Z (H2A.Z). For a better understanding the physiological function of Nrf2 in animals and as a potential target for future research on protein roles in Nrf2 interactions, it is crucial to clarify these protein interactions.

The crosstalk between Nrf2 and NF-κB pathways in coronary artery disease: Can it be regulated by SIRT6?

Coronary artery disease (CAD) is the leading cause of death worldwide. Oxidative stress and inflammation are major mechanisms responsible for the progression of CAD. Nuclear transcription factor erythroid-2 related factor 2 (Nrf2) is a transcription factor that modulates the cellular redox status. Nrf2 upregulation increases the expression of antioxidant genes, decreases the expression of Nuclear factor-kappa B (NF-kB), and increases free radical metabolism. Activated NF-kB increases the production of inflammatory cytokines causing endothelial dysfunction. The two pathways of Nrf2 and NF-kB can regulate the expression of each other. Foremost, the Nrf2 pathway can decrease the level of active NF-κB by increasing the level of antioxidants and cytoprotective enzymes. Furthermore, the Nrf2 pathway prevents IκB-α degradation, an inhibitor of NF-kB, and thus inhibits NF-κB mediated transcription. Also, NF-kB transcription inhibits Nrf2 activation by reducing the antioxidant response element (ARE) transcription. Sirtuin 6 (SIRT6) is a member of the Sirtuins family that was found to protect against cardiovascular diseases. SIRT6 can suppress the production of Reactive oxygen species (ROS) through deacetylation of NRF2 which results in NRF2 activation. Furthermore, SIRT6 can inhibit the inflammatory process through the downregulation of NF-kB transcription. Therefore, targeting sirtuins could be a therapeutic strategy to treat CAD. This review describes the potential role of SIRT6 in regulating the crosstalk between NRF2 and NF-kB signaling pathways in CAD.

Interleukin-17D produced by alveolar epithelial type II cells alleviates LPS-induced acute lung injury via the Nrf2 pathway

BACKGROUND

Sepsis engenders an imbalance in the body's inflammatory response, with cytokines assuming a pivotal role in its progression. A relatively recent addition to the interleukin-17 family, denominated interleukin-17D (IL-17D), is notably abundant within pulmonary confines. Nevertheless, its implication in sepsis remains somewhat enigmatic. The present study endeavors to scrutinize the participation of IL-17D in sepsis-induced acute lung injury (ALI).

METHODS

The levels of IL-17D in the serum and bronchoalveolar lavage fluid (BALF) of both healthy cohorts and septic patients were ascertained through an ELISA protocol. For the creation of a sepsis-induced ALI model, intraperitoneal lipopolysaccharide (LPS) injections were administered to male C57/BL6 mice. Subsequently, we examined the fluctuations and repercussions associated with IL-17D in sepsis-induced ALI, probing its interrelation with nuclear factor erythroid 2-related factor 2 (Nrf2), alveolar epithelial permeability, and heme oxygenase-1.

RESULTS

IL-17D levels exhibited significant reduction both in the serum and BALF of septic patients (P<0.001). Similar observations manifested in mice subjected to LPS-induced acute lung injury (ALI) (P=0.002). Intraperitoneal administration of recombinant interleukin 17D protein (rIL-17D) prompted increased expression of claudin 18 and concomitant enhancement of alveolar epithelial permeability, thus, culminating in improved lung injury (P<0.001). Alveolar epithelial type II (ATII) cells were identified as the source of IL-17D, regulated by Nrf2. Furthermore, a deficiency in HO-1 yielded elevated IL-17D levels (P=0.004), albeit administration of rIL-17D ameliorated the exacerbated pulmonary damage resulting from HO-1 deficiency.

CONCLUSION

Nrf2 fosters IL-17D production within AT II cells, thereby conferring a protective role in sepsis-induced ALI.

Nrf2 signaling pathway: current status and potential therapeutic targetable role in human cancers

Cancer is a borderless global health challenge that continues to threaten human health. Studies have found that oxidative stress (OS) is often associated with the etiology of many diseases, especially the aging process and cancer. Involved in the OS reaction as a key transcription factor, Nrf2 is a pivotal regulator of cellular redox state and detoxification. Nrf2 can prevent oxidative damage by regulating gene expression with antioxidant response elements (ARE) to promote the antioxidant response process. OS is generated with an imbalance in the redox state and promotes the accumulation of mutations and genome instability, thus associated with the establishment and development of different cancers. Nrf2 activation regulates a plethora of processes inducing cellular proliferation, differentiation and death, and is strongly associated with OS-mediated cancer. What's more, Nrf2 activation is also involved in anti-inflammatory effects and metabolic disorders, neurodegenerative diseases, and multidrug resistance. Nrf2 is highly expressed in multiple human body parts of digestive system, respiratory system, reproductive system and nervous system. In oncology research, Nrf2 has emerged as a promising therapeutic target. Therefore, certain natural compounds and drugs can exert anti-cancer effects through the Nrf2 signaling pathway, and blocking the Nrf2 signaling pathway can reduce some types of tumor recurrence rates and increase sensitivity to chemotherapy. However, Nrf2's dual role and controversial impact in cancer are inevitable consideration factors when treating Nrf2 as a therapeutic target. In this review, we summarized the current state of biological characteristics of Nrf2 and its dual role and development mechanism in different tumor cells, discussed Keap1/Nrf2/ARE signaling pathway and its downstream genes, elaborated the expression of related signaling pathways such as AMPK/mTOR and NF-κB. Besides, the main mechanism of Nrf2 as a cancer therapeutic target and the therapeutic strategies using Nrf2 inhibitors or activators, as well as the possible positive and negative effects of Nrf2 activation were also reviewed. It can be concluded that Nrf2 is related to OS and serves as an important factor in cancer formation and development, thus provides a basis for targeted therapy in human cancers.

Spotlight on iron and ferroptosis: research progress in diabetic retinopathy

Iron, as the most abundant metallic element within the human organism, is an indispensable ion for sustaining life and assumes a pivotal role in governing glucose and lipid metabolism, along with orchestrating inflammatory responses. The presence of diabetes mellitus (DM) can induce aberrant iron accumulation within the corporeal system. Consequentially, iron overload precipitates a sequence of important adversities, subsequently setting in motion a domino effect wherein ferroptosis emerges as the utmost pernicious outcome. Ferroptosis, an emerging variant of non-apoptotic regulated cell death, operates independently of caspases and GSDMD. It distinguishes itself from alternative forms of controlled cell death through distinctive morphological and biochemical attributes. Its principal hallmark resides in the pathological accrual of intracellular iron and the concomitant generation of iron-driven lipid peroxides. Diabetic retinopathy (DR), established as the predominant cause of adult blindness, wields profound influence over the well-being and psychosocial strain experienced by afflicted individuals. Presently, an abundance of research endeavors has ascertained the pervasive engagement of iron and ferroptosis in the microangiopathy inherent to DR. Evidently, judicious management of iron overload and ferroptosis in the early stages of DR bears the potential to considerably decelerate disease progression. Within this discourse, we undertake a comprehensive exploration of the regulatory mechanisms governing iron homeostasis and ferroptosis. Furthermore, we expound upon the subsequent detriments induced by their dysregulation. Concurrently, we elucidate the intricate interplay linking iron overload, ferroptosis, and DR. Delving deeper, we engage in a comprehensive deliberation regarding strategies to modulate their influence, thereby effecting prospective interventions in the trajectory of DR's advancement or employing them as therapeutic modalities.

Pyroptosis, ferroptosis, and autophagy cross-talk in glioblastoma opens up new avenues for glioblastoma treatment

Glioma is a common primary tumor of the central nervous system (CNS), with glioblastoma multiforme (GBM) being the most malignant, aggressive, and drug resistant. Most drugs are designed to induce cancer cell death, either directly or indirectly, but malignant tumor cells can always evade death and continue to proliferate, resulting in a poor prognosis for patients. This reflects our limited understanding of the complex regulatory network that cancer cells utilize to avoid death. In addition to classical apoptosis, pyroptosis, ferroptosis, and autophagy are recognized as key cell death modalities that play significant roles in tumor progression. Various inducers or inhibitors have been discovered to target the related molecules in these pathways, and some of them have already been translated into clinical treatment. In this review, we summarized recent advances in the molecular mechanisms of inducing or inhibiting pyroptosis, ferroptosis, or autophagy in GBM, which are important for treatment or drug tolerance. We also discussed their links with apoptosis to better understand the mutual regulatory network among different cell death processes. Video Abstract.

Itaconate: A Potent Macrophage Immunomodulator

With advances in immunometabolic studies, more and more evidence has shown that metabolic changes profoundly affect the immune function of macrophages. The tricarboxylic acid cycle is a central metabolic pathway of cells. Itaconate, a byproduct of the tricarboxylic acid cycle, is an emerging metabolic small molecule that regulates macrophage inflammation and has received much attention for its potent anti-inflammatory effects in recent years. Itaconate regulates macrophage function through multiple mechanisms and has demonstrated promising therapeutic potential in a variety of immune and inflammatory diseases. New progress in the mechanism of itaconate continues to be made, but it also implies complexity in its action and a need for a more comprehensive understanding of its role in macrophages. In this article, we review the primary mechanisms and current research progress of itaconate in regulating macrophage immune metabolism, hoping to provide new insights and directions for future research and disease treatment.

A review on pharmacokinetics of sinomenine and its anti-inflammatory and immunomodulatory effects

Autoimmune diseases (ADs), with significant effects on morbidity and mortality, are a broad spectrum of disorders featured by body's immune responses being directed against its own tissues, resulting in chronic inflammation and tissue damage. Sinomenine (SIN) is an alkaloid isolated from the root and stem of Sinomenium acutum which is mainly used to treat pain, inflammation and immune disorders for centuries in China. Its potential anti-inflammatory role for treating immune-related disorders in experimental animal models and in some clinical applications have been reported widely, suggesting an inspiring application prospect of SIN. In this review, the pharmacokinetics, drug delivery systems, pharmacological mechanisms of action underlying the anti-inflammatory and immunomodulatory effects of SIN, and the possibility of SIN as adjuvant to disease-modifying anti-rheumatic drugs (DMARDs) therapy were summarized and evaluated. This paper aims to reveal the potential prospects and limitations of SIN in the treatment of inflammatory and immune diseases, and to provide ideas for compensating its limitations and reducing the side effects, and thus to make SIN better translate to the clinic.

Beyond Antioxidation: Keap1-Nrf2 in the Development and Effector Functions of Adaptive Immune Cells

Ubiquitously expressed in mammalian cells, the Kelch-like ECH-associated protein 1 (Keap1)-NF erythroid 2-related factor 2 (Nrf2) complex forms the evolutionarily conserved antioxidation system to tackle oxidative stress caused by reactive oxygen species. Reactive oxygen species, generated as byproducts of cellular metabolism, were identified as essential second messengers for T cell signaling, activation, and effector responses. Apart from its traditional role as an antioxidant, a growing body of evidence indicates that Nrf2, tightly regulated by Keap1, modulates immune responses and regulates cellular metabolism. Newer functions of Keap1 and Nrf2 in immune cell activation and function, as well as their role in inflammatory diseases such as sepsis, inflammatory bowel disease, and multiple sclerosis, are emerging. In this review, we highlight recent findings about the influence of Keap1 and Nrf2 in the development and effector functions of adaptive immune cells, that is, T cells and B cells, and discuss the knowledge gaps in our understanding. We also summarize the research potential and targetability of Nrf2 for treating immune pathologies.

PDIA4 confers resistance to ferroptosis via induction of ATF4/SLC7A11 in renal cell carcinoma

The prognosis of renal cell carcinoma (RCC) remains poor due to metastases and resistance to chemotherapy. Salinomycin (Sal) exhibits the potential of antitumor, while the underlying mechanism is not completely clear. Here, we found that Sal induced ferroptosis in RCCs and identified Protein Disulfide Isomerase Family A Member 4 (PDIA4) as a mediator of Sal's effect on ferroptosis. Sal suppressed PDIA4 by increasing its autophagic degradation. Downregulation of PDIA4 increased the sensitivity to ferroptosis, while ectopic overexpression of PDIA4 conferred ferroptosis resistance to RCCs. Our data showed that downregulation of PDIA4 suppressed activating transcription factor 4 (ATF4) and its downstream protein SLC7A11 (solute carrier family 7 member 11), thereby aggravating ferroptosis. In vivo, the administration of Sal promoted ferroptosis and suppressed tumor progress in the xenograft mouse model of RCC. Bioinformatical analyses based on clinical tumor samples and database indicated a positive correlation exists between PDIA4 and PERK/ATF4/SLC7A11 signaling pathway, as well as the malignant prognosis of RCCs. Together, our findings reveal that PDIA4 promotes ferroptosis resistance in RCCs. Treatment of Sal sensitizes RCC to ferroptosis via suppressing PDIA4, suggesting the potential therapeutical application in RCCs.

USP13 reduces septic mediated cardiomyocyte oxidative stress and inflammation by inducing Nrf2

BACKGROUND

Sepsis is a common cardiovascular complication that can cause heart damage. The regulatory role of ubiquitin-specific peptidase 13 (USP13) on erythroid 2-related factor 2 (Nrf2) has been reported, but its regulatory role in septic cardiomyopathy remains unclear.

METHODS

The Sprague Dawley (SD) rat model of septic myocardial injury was constructed by lipopolysaccharides (LPS). The serum lactate dehydrogenase (LDH) and creatine kinase (CK) levels were detected, the mRNA and protein expression levels of Nrf2 and USP13 in tissues were detected by real-time quantitative reverse transcription PCR (qRT-PCR) and western blot (WB), and the expression of USP13 at the treatment time of 3 h, 6 h, and 12 h was also detected. The cell viability and USP13, Nrf-2 and heme oxygenase-1 (HO-1) expression levels of H9C2-treated cells by LPS and the oxidative stress level and inflammatory response of H9C2 cells were detected by enzyme-linked immunosorbent assay (ELISA) and WB.

RESULTS

The results showed that USP13 was downregulated in septic myocardial injury tissues, and the Nrf2 level was increased in vitro after the cells were treated with LPS. Overexpression of USP13 further induced Nrf2 to reduce apoptosis, oxidative stress, and expression of inflammatory factors.

CONCLUSION

In conclusion, this study demonstrated that USP13 was downregulated in septic myocardial injury tissues, and USP13 overexpression increased Nrf2 levels and reduced apoptosis. Further studies showed that USP13 reduced LPS-induced oxidative stress and inflammation by inducing Nrf2.

Toxicity of titanium dioxide nanoparticles on the histology, liver physiological and metabolism, and intestinal microbiota of grouper

Titanium dioxide nanoparticles (nano-TiO₂) are a common environmental pollutant threatening aquatic animals. The natural habitats and cultured environments of groupers make them vulnerable to nanoparticle pollution. In this study, hybrid grouper juveniles were separately exposed to 1 or 10 mg/L nano-TiO₂ for 14 days, and the toxicological response of these groupers were investigated. After nano-TiO₂ exposure, the liver showed apparent histopathology and intestinal goblet cells were also affected. The transcription of antioxidant and apoptosis-related genes were down-regulated, and the inflammatory factor TNF-α was up-regulated in the liver. The metabolite patterns of the liver were disturbed, especially amino acid metabolism. The diversity and composition of the intestinal microbiota were also altered especially the genera Lactobacillus and Nautella. The changes of several intestinal bacteria were correlated with the immune factors and metabolites of respective hosts. We concluded that nano-TiO₂ exposure negatively affects the physiological homeostasis of groupers.

Moderate-Intensity Exercise Maintains Redox Homeostasis for Cardiovascular Health

It is well known that exercise is beneficial for cardiovascular health. Oxidative stress is the common pathological basis of many cardiovascular diseases. The overproduction of free radicals, both reactive oxygen species and reactive nitrogen species, can lead to redox imbalance and exacerbate oxidative damage to the cardiovascular system. Maintaining redox homeostasis and enhancing anti-oxidative capacity are critical mechanisms by which exercise protects against cardiovascular diseases. Moderate-intensity exercise is an effective means to maintain cardiovascular redox homeostasis. Moderate-intensity exercise reduces the risk of cardiovascular disease by improving mitochondrial function and anti-oxidative capacity. It also attenuates adverse cardiac remodeling and enhances cardiac function. This paper reviews the primary mechanisms of moderate-intensity exercise-mediated redox homeostasis in the cardiovascular system. Exploring the role of exercise-mediated redox homeostasis in the cardiovascular system is of great significance to the prevention and treatment of cardiovascular diseases.

USP13 reduces septic mediated cardiomyocyte oxidative stress and inflammation by inducing Nrf2

BACKGROUND

Sepsis is a common cardiovascular complication that can cause heart damage. The regulatory role of ubiquitin-specific peptidase 13 (USP13) on erythroid 2-related factor 2 (Nrf2) has been reported, but its regulatory role in septic cardiomyopathy remains unclear.

METHODS

The Sprague Dawley (SD) rat model of septic myocardial injury was constructed by lipopolysaccharides (LPS). The serum lactate dehydrogenase (LDH) and creatine kinase (CK) levels were detected, the mRNA and protein expression levels of Nrf2 and USP13 in tissues were detected by real-time quantitative reverse transcription PCR (qRT-PCR) and western blot (WB), and the expression of USP13 at the treatment time of 3 h, 6 h, and 12 h was also detected. The cell viability and USP13, Nrf-2 and heme oxygenase-1 (HO-1) expression levels of H9C2-treated cells by LPS and the oxidative stress level and inflammatory response of H9C2 cells were detected by enzyme-linked immunosorbent assay (ELISA) and WB.

RESULTS

The results showed that USP13 was downregulated in septic myocardial injury tissues, and the Nrf2 level was increased in vitro after the cells were treated with LPS. Overexpression of USP13 further induced Nrf2 to reduce apoptosis, oxidative stress, and expression of inflammatory factors.

CONCLUSION

In conclusion, this study demonstrated that USP13 was downregulated in septic myocardial injury tissues, and USP13 overexpression increased Nrf2 levels and reduced apoptosis. Further studies showed that USP13 reduced LPS-induced oxidative stress and inflammation by inducing Nrf2.

Leucine protects bovine intestinal epithelial cells from hydrogen peroxide-induced apoptosis by alleviating oxidative damage

BACKGROUND

The present study aimed to investigate whether leucine (Leu) alleviates oxidative injury in bovine intestinal epithelial cells (BIECs) induced by hydrogen peroxide (H₂ O₂ ), as well as the underlying molecular mechanisms.

RESULTS

BIECs were treated with H₂ O₂ (1 mmol L^-1 ) and/or Leu (0, 0.9, 1.8 or 3.6 mmol L^-1 ) for 2 h. Leu increased cell viability (P < 0.05) and decreased the release of lactate dehydrogenase (P < 0.05) in BIECs challenged by H₂ O₂ . Then, the cells were treated with H₂ O₂ (1 mmol L^-1 ) and/or Leu (1.8 mmol L^-1 ) for 2 h. Compared with the H₂ O₂ group, cells treated with Leu and Leu + H₂ O₂ exhibited increased (P < 0.05) mRNA and protein expression of superoxide dismutase 2 (SOD2), catalase (CAT), glutathione peroxidase 1 (GPx1), heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2). BIECs treatment with Leu significantly reduced (P < 0.05) apoptosis induced by H₂ O₂ . BIECs were transfected with Nrf2 small interfering RNA (siRNA) for 48 h and/or treated with H₂ O₂ (1 mmol L^-1 ) and/or Leu (1.8 mmol L^-1 ) for another 2 h. Transfection with Nrf2 siRNA abrogated the protective effect of Leu against H₂ O₂ -induced apoptosis and the mRNA and protein expression of SOD2 (P < 0.05).

CONCLUSION

These results indicate that Leu promotes the relative expression of antioxidant enzymes (SOD2, CAT and GPx1) and phase II detoxification enzymes (HO-1) by upregulating nuclear Nrf2 and activating the Nrf2 signaling pathway, thus enhancing the antioxidant capacity of cells. © 2022 Society of Chemical Industry.

Redox regulation of the immune response

The immune-inflammatory response is associated with increased nitro-oxidative stress. The aim of this mechanistic review is to examine: (a) the role of redox-sensitive transcription factors and enzymes, ROS/RNS production, and the activity of cellular antioxidants in the activation and performance of macrophages, dendritic cells, neutrophils, T-cells, B-cells, and natural killer cells; (b) the involvement of high-density lipoprotein (HDL), apolipoprotein A1 (ApoA1), paraoxonase-1 (PON1), and oxidized phospholipids in regulating the immune response; and (c) the detrimental effects of hypernitrosylation and chronic nitro-oxidative stress on the immune response. The redox changes during immune-inflammatory responses are orchestrated by the actions of nuclear factor-κB, HIF1α, the mechanistic target of rapamycin, the phosphatidylinositol 3-kinase/protein kinase B signaling pathway, mitogen-activated protein kinases, 5' AMP-activated protein kinase, and peroxisome proliferator-activated receptor. The performance and survival of individual immune cells is under redox control and depends on intracellular and extracellular levels of ROS/RNS. They are heavily influenced by cellular antioxidants including the glutathione and thioredoxin systems, nuclear factor erythroid 2-related factor 2, and the HDL/ApoA1/PON1 complex. Chronic nitro-oxidative stress and hypernitrosylation inhibit the activity of those antioxidant systems, the tricarboxylic acid cycle, mitochondrial functions, and the metabolism of immune cells. In conclusion, redox-associated mechanisms modulate metabolic reprogramming of immune cells, macrophage and T helper cell polarization, phagocytosis, production of pro- versus anti-inflammatory cytokines, immune training and tolerance, chemotaxis, pathogen sensing, antiviral and antibacterial effects, Toll-like receptor activity, and endotoxin tolerance.

Novel role of macrophage TXNIP-mediated CYLD-NRF2-OASL1 axis in stress-induced liver inflammation and cell death

Background & Aims

The stimulator of interferon genes (STING)/TANK-binding kinase 1 (TBK1) pathway is vital in mediating innate immune and inflammatory responses during oxidative/endoplasmic reticulum (ER) stress. However, it remains unknown whether macrophage thioredoxin-interacting protein (TXNIP) may regulate TBK1 function and cell death pathways during oxidative/ER stress.

Methods

A mouse model of hepatic ischaemia/reperfusion injury (IRI), the primary hepatocytes, and bone marrow-derived macrophages were used in the myeloid-specific TXNIP knockout (TXNIPM-KO) and TXNIP-proficient (TXNIPFL/FL) mice.

Results

The TXNIPM-KO mice were resistant to ischaemia/reperfusion (IR) stress-induced liver damage with reduced serum alanine aminotransferase (ALT)/aspartate aminotransferase (AST) levels, macrophage/neutrophil infiltration, and pro-inflammatory mediators compared with the TXNIPFL/FL controls. IR stress increased TXNIP, p-STING, and p-TBK1 expression in ischaemic livers. However, TXNIPM-KO inhibited STING, TBK1, interferon regulatory factor 3 (IRF3), and NF-κB activation with interferon-β (IFN-β) expression. Interestingly, TXNIPM-KO augmented nuclear factor (erythroid-derived 2)-like 2 (NRF2) activity, increased antioxidant gene expression, and reduced macrophage reactive oxygen species (ROS) production and hepatic apoptosis/necroptosis in IR-stressed livers. Mechanistically, macrophage TXNIP deficiency promoted cylindromatosis (CYLD), which colocalised and interacted with NADPH oxidase 4 (NOX4) to enhance NRF2 activity by deubiquitinating NOX4. Disruption of macrophage NRF2 or its target gene 2',5' oligoadenylate synthetase-like 1 (OASL1) enhanced Ras GTPase-activating protein-binding protein 1 (G3BP1) and TBK1-mediated inflammatory response. Notably, macrophage OASL1 deficiency induced hepatocyte apoptotic peptidase activating factor 1 (APAF1), cytochrome c, and caspase-9 activation, leading to increased caspase-3-initiated apoptosis and receptor-interacting serine/threonine-protein kinase 3 (RIPK3)-mediated necroptosis.

Conclusions

Macrophage TXNIP deficiency enhances CYLD activity and activates the NRF2-OASL1 signalling, controlling IR stress-induced liver injury. The target gene OASL1 regulated by NRF2 is crucial for modulating STING-mediated TBK1 activation and Apaf1/cytochrome c/caspase-9-triggered apoptotic/necroptotic cell death pathway. Our findings underscore a novel role of macrophage TXNIP-mediated CYLD-NRF2-OASL1 axis in stress-induced liver inflammation and cell death, implying the potential therapeutic targets in liver inflammatory diseases.

Lay summary

Liver inflammation and injury induced by ischaemia and reperfusion (the absence of blood flow to the liver tissue followed by the resupply of blood) is a significant cause of hepatic dysfunction and failure following liver transplantation, resection, and haemorrhagic shock. Herein, we uncover an underlying mechanism that contributes to liver inflammation and cell death in this setting and could be a therapeutic target in stress-induced liver inflammatory injury.

Innate immunity and immunotherapy for hemorrhagic shock

Hemorrhagic shock (HS) is a shock result of hypovolemic injury, in which the innate immune response plays a central role in the pathophysiology ofthe severe complications and organ injury in surviving patients. During the development of HS, innate immunity acts as the first line of defense, mediating a rapid response to pathogens or danger signals through pattern recognition receptors. The early and exaggerated activation of innate immunity, which is widespread in patients with HS, results in systemic inflammation, cytokine storm, and excessive activation of complement factors and innate immune cells, comprised of type II innate lymphoid cells, CD4⁺ T cells, natural killer cells, eosinophils, basophils, macrophages, neutrophils, and dendritic cells. Recently, compelling evidence focusing on the innate immune regulation in preclinical and clinical studies promises new treatment avenues to reverse or minimize HS-induced tissue injury, organ dysfunction, and ultimately mortality. In this review, we first discuss the innate immune response involved in HS injury, and then systematically detail the cutting-edge therapeutic strategies in the past decade regarding the innate immune regulation in this field; these strategies include the use of mesenchymal stem cells, exosomes, genetic approaches, antibody therapy, small molecule inhibitors, natural medicine, mesenteric lymph drainage, vagus nerve stimulation, hormones, glycoproteins, and others. We also reviewed the available clinical studies on immune regulation for treating HS and assessed the potential of immune regulation concerning a translation from basic research to clinical practice. Combining therapeutic strategies with an improved understanding of how the innate immune system responds to HS could help to identify and develop targeted therapeutic modalities that mitigate severe organ dysfunction, improve patient outcomes, and reduce mortality due to HS injury.

A new antioxidant made from a pterostilbene functionalized graphene nanocomposite as an efficient treatment for dry eye disease

Dry eye disease is a common condition that affects the eyes. It is caused by problems with the tear film and the tear dynamics. Dry eye can be caused by an increase in the amount of reactive oxygen species (ROS) in the corneal epithelium. The treatment for dry eye typically focuses on relieving the uncomfortable symptoms by using eye drops such as artificial tears, antibiotics, and by using anti-inflammatory/immunosuppressive agents such as cyclosporine, and lifitegrast. However, the recovery of patients with dry eye can take several years particularly if the symptoms are severe. This is because the present treatment approaches for dry eye are not based on its cause, e.g., the oxidative stress arising from the rapid increase in ROS. This work describes a new type of antioxidant made from pterostilbene (PS) and carboxyl-chitosan modified graphene (CG). The use of a hydrophilic two-dimensional CG nanosheet to improve the properties of PS is reported. Superior enhanced properties including better cellular permeability, long sustained release period (over 30 h), and antioxidant properties, were realized by using PS-CG. A hyperosmotic (HS) damaged human corneal epithelial cell (HCEC) model was used for antioxidant tests. This model has an intracellular ROS level 4 times more than that of a control group. The ROS content was declined efficiently to the same amount as normal cells in the PS-CG treated HS group. There was a significant decline in the content of lactate dehydrogenase (LDH) and the apoptosis rate of HCEC in the PS-CG treated HS group when compared to that seen in the HS model. Real-time polymerase chain reaction (PCR) and western blots (WB) were used to understand the antioxidant mechanism of PS-CG. The results showed that the antioxidant was working by activating the Keap1-Nrf2-ARE signalling pathway. In vivo testing testing using a dry eye mouse model suggested that the PS-CG acted as an efficient antioxidant. More tear production and healthier corneal and conjunctival epithelial cells were achieved when PC-CG was applied to this model. The use of PS-CG could be a new strategy for treating dry eye and other ocular diseases caused by ROS.