Nrf2 Target Research Articles

Altered hypoxia- and redox-related transcriptional signatures in mitochondrial-DNA-depleted PC-3 cells

Rho 0 (ρ0) cells are widely used as a tool to investigate how the absence of respiring mitochondria affects a variety of physiological and pathological processes. Prominently, ρ0 cells have been used to study the role of mitochondrial reactive oxygen species (ROS) production and/or mitochondrial respiration in the stabilization of the hypoxia-inducible factor (HIF) in hypoxia. In this study, we cultured ρ0 and WT PC-3 cells in 5% O2 (physioxia) and Plasmax medium for 2 weeks prior to transcriptomic and functional analyses. RNA-seq showed that ρ0 PC-3 cells exhibit impaired induction of HIF-regulated genes when exposed to hypoxia, compared to wild-type (WT) cells. Surprisingly, when comparing the transcriptomes of ρ0 and WT cells in physioxia (5% O2), we found a strong presence of HIF-related gene signatures in ρ0 cells compared to WT. Among the HIF targets found to be upregulated in ρ0 cells are CA9, EGLN3, EPAS1, HK2, ENO2, and SLC2A1. Moreover, several Nrf2 targets were upregulated in ρ0 cells, including NQO1, HMOX1, GPX2, and SLC7A11, which is in line with ρ0 cells showing a significantly higher H2O2 efflux rate than WT cells. Given the alterations in HIF-dependent and Nrf2-dependent gene expression and basal ROS production observed in ρ0 PC-3 cells, we conclude that caution should be taken when interpreting the results from experiments that focus on ROS production and HIF signaling using ρ0 cells as a model.

Mechanism of Action and Related Natural Regulators of Nrf2 in Nonalcoholic Fatty Liver Disease.

With the acceleration of people's pace of life, non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in the world, which greatly threatens people's health and safety. Therefore, there is still an urgent need for higher-quality research and treatment in this area. Nuclear factor Red-2-related factor 2 (Nrf2), as a key transcription factor in the regulation of oxidative stress, plays an important role in inducing the body's antioxidant response. Although there are no approved drugs targeting Nrf2 to treat NAFLD so far, it is still of great significance to target Nrf2 to alleviate NAFLD. In recent years, studies have reported that many natural products treat NAFLD by acting on Nrf2 or Nrf2 pathways. This article reviews the role of Nrf2 in the pathogenesis of NAFLD and summarizes the currently reported natural products targeting Nrf2 or Nrf2 pathway for the treatment of NAFLD, which provides new ideas for the development of new NAFLD-related drugs.

Trilobatin as a potential adjuvant therapy for NAFLD: Targeting AMPK-PPARα and Nrf2 antioxidant pathways

Trilobatin as a potential adjuvant therapy for NAFLD: Targeting AMPK-PPARα and Nrf2 antioxidant pathways

MiR-142-5p mediated Nrf2 dysregulation in gestational diabetes mellitus and its impact on placental angiogenesis

Gestational diabetes mellitus (GDM) presents significant risks during pregnancy, including adverse perinatal outcomes and placental dysfunction. Impaired angiogenesis, involving crucial factors like Vascular Endothelial Growth Factor (VEGF), contributes to these complications. The Nrf2/Keap1 pathway, crucial for vascular redox homeostasis, has been linked to GDM-associated angiogenesis dysregulation. This study aimed to investigate the molecular mechanisms underlying placental Nrf2 regulation, focusing on angiomiRs, key regulators of angiogenesis in GDM. Computational analysis identified miR-142-5p targeting Nrf2 mRNA. Expression levels of miR-142-5p were assessed in GDM placenta and correlated with Nrf2 expression. Experimental validation utilized human trophoblastic cell lines (BeWo) exposed to hyperglycemic conditions, assessing the effects of anti-miR-142 transfection on Nrf2 expression and angiogenic marker levels. miR-142-5p expression was significantly downregulated in GDM placenta, correlating positively with Nrf2 expression. In BeWo cells exposed to hyperglycemia, anti-miR-142 transfection notably increased Nrf2 expression alongside angiogenic marker levels, confirming the computational predictions. Our findings highlight the pivotal role of miRNAs in GDM-associated impaired angiogenesis by modulating Nrf2 expression. Understanding these molecular mechanisms provides insights into potential therapeutic targets for improving pregnancy outcomes in GDM cases.

Andrographolide attenuates SARS-CoV-2 infection via an up-regulation of glutamate-cysteine ligase catalytic subunit (GCLC)

BackgroundAndrographolide is a medicinal compound which possesses anti-SARS-CoV-2 activity. A number of cellular targets of andrographolide have been identified by target predictions and computational studies. PurposeHowever, a potential cellular target of andrographolide has never been explored in SARS-CoV-2 infected lung epithelial cells. We aimed to identify cellular pathways involved in andrographolide-mediated anti-SARS-CoV-2 activity. MethodsThe viral infection was determined by immunofluorescence staining, enzyme-linked immunosorbent assay and focus-forming assay. Proteomic analysis was employed to identify cellular pathways and key proteins controlled by andrographolide in the human lung epithelial cells Calu-3 infected by SARS-CoV-2. Immunofluorescence staining was used to test protein expression and localization. Western blot and realtime PCR were utilized to elucidate gene expression. Cellular glutathione level was examined by a reduced/oxidized glutathione assay. An ectopic gene expression was delivered by plasmid transfection. ResultsGene ontology analysis indicates that proteins involved in nuclear factor erythroid 2-related factor 2 (NRF2)-regulated pathways were differentially expressed by andrographolide. Notably, andrographolide increased expression and nuclear localization of the transcription factor NRF2. In addition, transcriptional expression of GCLC and glutamate-cysteine ligase modifier subunit (GCLM), which are NRF2 target genes, were induced by andrographolide. We further find that infection of SARS-CoV-2 resulted in a reduction of glutathione level in Calu-3; the effect that was rescued by andrographolide. Moreover, andrographolide also induced expression of the glutathione producing enzyme GCLC in SARS-CoV-2 infected lung epithelial cells. Importantly, an ectopic over-expression of GCLC or treatment of N-acetyl-L-cysteine in Calu-3 cells led to a decrease in SARS-CoV-2 infection. ConclusionCollectively, our findings suggest the interplay between GCLC-mediated glutathione biogenesis induced by andrographolide and the anti-SARS-CoV-2 activity. The glutathione biogenesis and recycling pathways should be further exploited as a targeted therapy against SARS-CoV-2 infection.

ΔNp63α promotes radioresistance in esophageal squamous cell carcinoma through the PLEC-KEAP1-NRF2 feedback loop.

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers and is highly prevalent in China, exhibiting resistance to current treatments. ΔNP63α, the main isoform of p63, is frequently amplified in ESCC and contributes to therapeutic resistance, although the molecular mechanisms remain unknown. Here, we report that ΔNP63α is highly expressed in ESCC and is associated with radioresistance by reducing ROS level. Furthermore, ΔNP63α plays a critical role in radioresistance by directly transactivating the expression of PLEC. PLEC competitively interacts with KEAP1, resulting in the release of NRF2 from KEAP1 and its translocation from the cytosol to the nucleus, where it activates gene expression to facilitate ROS elimination. Additionally, radiotherapy-induced ROS also activates ΔNP63α expression via NRF2. Pharmacologic inhibition of NRF2 effectively improves radiosensitivity in nude mice. Collectively, our results strongly suggest that the ΔNp63α/PLEC/NRF2 axis plays a key role in radioresistance in ESCC, indicating that targeting NRF2 is a promising therapeutic approach for ESCC treatment.

Study on the Mechanism of Alpinia officinarum Hance in the Improvement of Insulin Resistance through Network Pharmacology, Molecular Docking and in vitro Experimental Verification.

Research has elucidated that the pathophysiological underpinnings of non-alcoholic fatty liver disease and type 2 diabetes mellitus are intrinsically linked to insulin resistance (IR). However, there are currently no pharmacotherapies specifically approved for combating IR. Although Alpinia officinarum Hance (A. officinarum) can ameliorate diabetes, the detailed molecular mechanism through which it influences IR has not been fully clarified. To predict the active components of A. officinarum and determine the mechanism by which A. officinarum affects IR. The active compounds and molecular mechanism underlying the improvement of IR by A. officinarum were predicted via network pharmacology and molecular docking. To further substantiate these predictions, an in vitro model of IR was induced in HepG2 cells using high glucose concentrations. Cytotoxicity and oxidative stress levels were evaluated using Cell Counting Kit-8, reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) assay kits. The putative molecular mechanisms were corroborated through Western blot and RT-PCR analyses. Fourteen principal active components in A. officinarum, 133 potential anti-IR gene targets, and the top five targets with degree values were ALB, AKT1, TNF, IL6, and VEGFA. A. officinarum was posited to exert its pharmacological effects on IR through mechanisms involving lipid and atherosclerosis, the AGE-RAGE signaling pathway in diabetic complications, the PI3K-AKT signaling pathway, fluid shear stress, and atherosclerosis. Intriguingly, network pharmacology analysis highlighted (4E)-7-(4-hydroxy-3-methoxyphenyl)-1-phenylhept-4-en-3- one (A14) as the most active compound. Molecular docking studies further confirmed that A14 has a strong binding affinity for the main targets of PI3K, AKT, and Nrf2. The experiments demonstrated that A14 significantly diminished the ROS and MDA levels while augmenting the SOD activity. Moreover, A14 was found to elevate the protein expression of PI3K, AKT, Nrf2, and HO-1, and increase the mRNA levels of these targets as well as NQO1. A. officinarum could play a therapeutic role in IR through multiple components, targets, and pathways. The most active component of A. officinarum responsible for combating IR is A14, which has the ability to regulate oxidative stress in IR-HepG2 cells by activating the PI3K/AKT/Nrf2 pathway. These findings suggest a potential pharmacological intervention strategy for the treatment of IR.

Intestinal microbiota-mediated serum pharmacochemistry reveals hepatoprotective metabolites of Platycodonis Radix against APAP-induced liver injury

The urgent need for new medications that regulate CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB activities is paramount for the treatment of drug-induced liver injury (DILI), particularly from acetaminophen (APAP). Previous studies have suggested that platycosides of Platycodonis Radix exhibits hepatoprotective properties against APAP-induced liver injury (AILI), and their serum metabolites may be the effective agents. As the identify the serum metabolites of platycosides is a huge challenge, the mechanism whether platycosides exert effects through the serum metabolites regulating those targets still remain unclear. In this study, we propose a novel method termed intestinal microbiota-mediated serum pharmacochemistry (IMSP) to identify the serum metabolite profile of platycosides, using deglycosylated platycosides as template molecules. Our results identified a total of 44 prototype platycosides in the total platycosides fraction of Platycodonis Radix (PF). In rat serum, we identified 12 prototype platycosides and 45 metabolites derived from the 44 platycosides. Furthermore, our findings indicate that all 44 platycosides can enter the serum in the form of metabolites. The presence of these metabolites in serum is closely related to their oral bioavailability and the content of the prototypes. The in vivo animal experiments showed that the PF possessed significant anti-AILI effects and CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB p65 regulation activities. And the in vitro cell experiments and molecular docking analyses further demonstrated that the hepatoprotective effects were mainly ascribed to the serum metabolites, which regulating targets of CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB p65. Additionally, the activities of these metabolites are closely associated with their structures. In summary, the IMSP method significantly enhances the ability to identify platycoside metabolites in serum, reveals that all platycosides may contribute to anti-AILI activity through their metabolites, PF and some of these metabolites are promising candidate compounds for developing new medications with anti-AILI effects for the first time.

Nuclear factor erythroid 2-related factor 2 alleviates lung endothelial cells injury by inhibition of ferroptosis.

In recent years, the survival rate of preterm infants has significantly improved due to the application of pulmonary surfactant (PS) and advancements in lung-protective mechanical ventilation strategies. However, this has been accompanied by an increased incidence of complications, particularly lung diseases triggered by elevated reactive oxygen species (ROS) induced by hyperoxia. The primary mechanism of hyperoxic lung injury (HLI) involves the excessive production of ROS within cells and the aggregation of inflammatory cells. Currently, no effective prevention or treatment methods are available. Ferroptosis, a newly identified form of cell death, is closely linked to ROS accumulation and is likely involved in HLI. Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates both HLI and ferroptosis, and targeting Nrf2 to inhibit ferroptosis may represent a key therapeutic approach for treating HLI. This study aimed to investigate the involvement of ferroptosis in HLI and to elucidate the regulatory role of Nrf2. We employed the human pulmonary microvascular endothelial cell (HPMEC) model of hyperoxia exposure and corresponding intervention groups. Mitochondrial morphological alterations within HPMECs exposed to hyperoxia and various control groups were examined using transmission electron microscopy (TEM). Cell viability was assessed via the Cell Counting Kit-8 (CCK-8) assay, whereas intracellular ROS levels were quantified using the dichlorodihydrofluorescein diacetate (DCFH-DA) probe. Furthermore, the expression levels of GPX4 and Nrf2 were analyzed through quantitative polymerase chain reaction (qPCR) and western blot techniques. Relative to the control group, the HPMECs subjected to hyperoxic conditions exhibited diminished viability, heightened ROS levels, decreased GPX4 expression, and increased Nrf2 expression. These cells also demonstrated mitochondrial morphological alterations characteristic of ferroptosis, including reduced mitochondrial cristae and shrinkage. The application of a ferroptosis inhibitor mitigated cellular damage, lipid peroxidation, and the morphological manifestations of mitochondrial ferroptosis, whereas Nrf2 inhibitor ML385 reversed this effect. Ferroptosis appears to contribute to the pathogenesis of HLI, with Nrf2 serving a protective function by mitigating ferroptosis.

Berberine safeguards sepsis-triggered acute gastric damage and inhibits pyroptosis in gastric epithelial cells via suppressing the ubiquitination and degradation of Nrf2.

Berberine (BBR), a widely recognized traditional Chinese medicine, has attracted considerable attention for its promising anti-inflammatory effects. The activation of nuclear factor erythroid 2-related factor 2 (Nrf2) effectively safeguards against organ damage stemming from sepsis-induced oxidative stress and inflammatory responses. This study examined the potential of BBR in alleviating sepsis-induced acute gastric injury, with a particular focus on elucidating whether its mechanism of action involves the activation of the Nrf2 signaling pathway. Following intraperitoneal injection of BBR, mice were subjected to the cecal ligation and puncture (CLP) method to induce sepsis. In vitro experiments involved pre-treating the normal gastric epithelial cells (GES-1) with BBR, followed by treatment with lipopolysaccharide (LPS). Functional assays were then performed to assess cell proliferation and apoptosis. To validate the role of Nrf2 in pyroptosis and inflammation, siRNA targeting Nrf2 (si-Nrf2) was transfected into LPS-treated GES-1 cells. Additionally, mice were administered the Nrf2 inhibitor ML385 to confirm the protective effects of BBR in vivo. BBR displayed a dose-dependent effect in mitigating gastric tissue damage, suppressing the release of inflammatory cytokines, and reducing the expression of NLRP3, ASC, and GSDMD-N. In vitro, BBR fostered GES-1 cell proliferation, hindered apoptosis, and suppressed the levels of TNF-α, IL-18, IL-1β, NLRP3, ASC, and GSDMD-N. Further analysis revealed that knocking down Nrf2 reversed BBR's inhibitory effect on pyroptosis in LPS-treated GES-1 cells. Through binding to Keap1, BBR efficiently prevented the ubiquitination and degradation of Nrf2, ultimately promoting its nuclear translocation. In vivo experiments confirmed that ML385 reversed the protective effect of BBR on pyroptosis and inflammation. Our research reveals that BBR interacts with Keap1 to activate the Keap1/Nrf2 signaling pathway in gastric epithelial cells, thereby suppressing pyroptosis and inflammation in sepsis-induced acute gastric injury.

Non-electrophilic NRF2 activators promote wound healing in human keratinocytes and diabetic mice and demonstrate selective downstream gene targeting

The transcription factor NRF2 plays an important role in many biological processes and is a promising therapeutic target for many disease states. NRF2 is highly expressed in the skin and is known to play a critical role in diabetic wound healing, a serious disease process for which treatment options are limited. However, many existing NRF2 activators display off-target effects due to their electrophilic mechanism, underscoring the need for alternative approaches. In this work, we investigated two recently described non-electrophilic NRF2 activators, ADJ-310 and PRL-295, and demonstrated their efficacy in vitro and in vivo in human keratinocytes and Leprdb/db diabetic mice. We also compared the downstream targets of PRL-295 to those of the widely used electrophilic NRF2 activator CDDO-Me by RNA sequencing. Both ADJ-310 and PRL-295 maintained human keratinocyte cell viability at increasing concentrations and maintained or improved cell proliferation over time. Both compounds also increased cell migration, improving in vitro wound closure. ADJ-310 and PRL-295 enhanced the oxidative stress response in vitro, and RNA-sequencing data showed that PRL-295 activated NRF2 with a narrower transcriptomic effect than CDDO-Me. In vivo, both ADJ-310 and PRL-295 improved wound healing in Leprdb/db diabetic mice and upregulated known downstream NRF2 target genes in treated tissue. These results highlight the non-electrophilic compounds ADJ-310 and PRL-295 as effective, innovative tools for investigating the function of NRF2. These compounds directly address the need for alternative NRF2 activators and offer a new approach to studying the role of NRF2 in human disease and its potential as a therapeutic across multiple disease states.

Nrf2 deficiency in muscle attenuates experimental autoimmune myositis-induced muscle weakness.

Idiopathic inflammatory myopathies (IIMs) are systemic autoimmune diseases characterised by muscle weakness. Although multiple physiological and pathological processes are associated with IIMs, T-lymphocyte infiltration into muscle plays a key role in the development and exacerbation of IIMs. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that regulates inflammatory responses; therefore, muscle Nrf2 may serve an important role in the development of IIMs. In this study, we demonstrated that experimental autoimmune myositis (EAM) causes loss of muscle mass and function in oxidative and glycolytic muscles in C57BL/6 mice. EAM increased CD4+ and CD8+ T-lymphocyte infiltration, as well as interferon-gamma (IFN-γ) and tumour necrosis factor-alpha (TNF-α) mRNA expression in oxidative soleus and glycolytic extensor digitorum longus muscles, along with elevated chemokine mRNA levels (i.e. CCL3, CCL5, CXCL9, CXCL10 and CXCL16). IFN-γ and TNF-α treatments increased the mRNA expression levels of these chemokines in C2C12 myotubes. EAM also increased phosphorylated Nrf2 at Ser40 in soleus and glycolytic white vastus lateralis muscle. Although the expression of several chemokines was affected by Nrf2 activation following tert-butylhydroquinone treatment or Keap1 knockdown, CCL5 mRNA expression significantly increased in C2C12 myotubes and mouse skeletal muscle. Moreover, muscle-specific Nrf2 knockout in mice attenuates EAM-induced loss of muscle mass and function, which was associated with the inhibition of CCL5 mRNA expression, CD8+ T-lymphocyte infiltration and IFN-γ mRNA expression. Collectively, these findings reveal that regulating Nrf2 activity is a promising therapeutic approach for treating IIM-mediated muscle weakness. KEY POINTS: Experimental autoimmune myositis (EAM) causes loss of muscle mass and function. Loss of muscle mass and function in EAM were associated with increased chemokine mRNA expression (i.e. CCL3, CCL5, CXCL9, CXCL10 and CXCL16), T-lymphocyte infiltration and inflammatory cytokine mRNA expression (i.e. IFN-γ and TNF-α) in the skeletal muscle. EAM activated Nrf2 in muscle and increased Nrf2 activity in vivo and in vitro increased CCL5 mRNA expression. Muscle-specific Nrf2 knockout in mice attenuated EAM-induced muscle weakness by inhibiting CCL5 mRNA expression, CD8+ T-lymphocyte migration and IFN-γ mRNA expression in muscles. These results provide further evidence for the potential therapeutic targeting of Nrf2 to mitigate EAM-induced muscle weakness.

Tobacco smoke exposure is a driver of altered oxidative stress response and immunity in head and neck cancer.

Exposomes are critical drivers of carcinogenesis. However, how they modulate tumor behavior remains unclear. Extensive clinical data link cigarette smoke as a key exposome that promotes aggressive tumors, higher rates of metastasis, reduced response to chemoradiotherapy, and suppressed anti-tumor immunity. We sought to determine whether smoke itself can modulate aggressive tumor behavior in head and neck squamous cell carcinoma (HNSCC) through reprogramming the cellular reductive state. Using established human and murine HNSCC cell lines and syngeneic mouse models, we utilized conventional western blotting, steady state and flux metabolomics, RNA sequencing, quantitative proteomics and flow cytometry to analyze the impact of smoke exposure on HNSCC tumor biology. Cigarette smoke persistently activated Nrf2 target genes essential for maintenance of the cellular reductive state and survival under conditions of increased oxidative stress in HNSCC regardless of HPV status. In contrast to e-cigarette vapor, conventional cigarette smoke mobilizes cellular metabolism toward oxidative stress adaptation, resulting in development of cross-resistance to cisplatin. In parallel, smoke exposure modulates both expression of PDL1 and the secretory phenotype of HNSCC cells through activation of NF-κB resulting in an altered tumor immune microenvironment (TIME) in syngeneic mouse models and altered PBMC differentiation that includes downregulated expression of antigen presentation and costimulatory genes in myeloid cells. Cigarette smoke exposome is a potent activator of the Nrf2 pathway and is a likely primary trigger for the tripartite phenotype of aggressive HNSCC consisting of: 1) reduced chemotherapy sensitivity, 2) enhanced metastatic potential and 3) suppressed anti-tumor immunity. The smoke exposome drives aggressive tumor behavior, treatment resistance and suppressed immunity through coordinated metabolic reprogramming. Successfully targeting this adaptation is critical to improving survival in smokers with head and neck cancer.

Targeting Nrf2 signaling in dry eye.

Dry eye, the most common ocular surface disease, can cause ocular surface tissue damage and discomfort symptoms and seriously affect people's quality of life. The etiology of dry eye is diverse, and its pathogenesis is complex. The oxidative stress reaction is considered to be among the important factors in the pathogenesis of dry eye. Therefore, activating the antioxidant system has a potential therapeutic effect on dry eye. Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway is considered the most important antioxidant pathway in the body. The activation of the Nrf2 signaling pathway and its interaction with other pathways are important mechanisms to prevent the occurrence and development of dry eye. This review describes the structure and function of Nrf2, summarizes the changes in the oxidative stress response in dry eye, focuses on the potential mechanism of the Nrf2 signaling pathway in the treatment of dry eye, and, finally, summarizes the drugs that activate the Nrf2 signaling pathway in the treatment of dry eye.

The Potential of Nanotechnology in Anti-Cancer Drug to Regulate Nrf2 Signaling for Cancer Therapeutic Purposes.

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a regulator of the cellular antioxidant defense system that plays an important role in reducing the risk of various pathophysiological conditions, including cancer. Targeting Nrf2 presents an attractive therapeutic approach to overcome these challenges and improve cancer treatment outcomes. Nanoparticles, with their unique physicochemical properties, offer several advantages over conventional therapies for targeting Nrf2. These include enhanced stability, improved permeability and retention effect, and precise targeting capabilities. Moreover, delivery systems based on nanotechnology have shown promise in overcoming the limitations of conventional cancer therapies, including ineffective precision targeting and momentous complications. The therapeutic efficacy of Nrf2 inhibitors may be enhanced by using nanoparticles for specific drug targeting and deeper tissue penetration. This involves optimizing nanoparticle formulations, understanding their interactions with the biological environment, and ensuring their safety and biocompatibility. Effective nanoparticle formulations are being developed to transport Nrf2 inhibitors, which can significantly improve treatment outcomes and address the limitations of conventional cancer therapies. Further studies are needed to explore the potential of nanotechnology in targeting Nrf2 for cancer therapeutic purposes.

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

BackgroundNOD 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. MethodsFluorescent 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. ResultsThis 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. ConclusionOur 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.

Transcriptomic profiling of lung fibroblasts in silicosis: Regulatory roles of Nrf2 agonists in a mouse model

Silicosis is an occupational disease caused by long-term inhalation of free silica, resulting in a significant global health burden. Its pathogenesis remains unclear, and there is no effective treatment. Proliferative and activated myofibroblasts play a key role in the development of silicosis. Traditional studies have focused on fibroblast proliferation and collagen secretion, neglecting their functional heterogeneity. With the advancement of omics research, more pathogenic fibroblast subgroups and their functions have been identified. In this study, we applied transcriptomics to analyze gene changes in primary lung fibroblasts during silicosis development using a mouse model. Our results indicate that DEGs are enriched in collagen secretion, ECM synthesis, leukocyte migration, and chemotaxis functions. Altered core genes are associated with immune cell recruitment and cell migration. Nrf2 agonists, known for anti-inflammatory and antioxidant properties, have shown potential therapeutic effects in fibrotic diseases. However, their effects on fibroblasts in silicosis are not fully understood. We used four common Nrf2 agonists to study gene expression changes in lung fibroblasts at the transcriptome level, combined with histopathological and biochemical methods, to investigate their effects on silicosis in mice. Results show that Nrf2 agonists can exert anti-silicosis fibrosis functions by downregulating genes like Fos and Egr1, involved in cell differentiation, proliferation, and inflammation. In conclusion, this study suggests that inflammation-related co-functions of fibroblasts may be a potential mechanism in silicosis pathogenesis. Targeting Nrf2 may be a promising strategy to alleviate oxidative stress and inflammation in silicosis.

233 (PB221): Therapeutic targeting of NRF2 increases sensitivity to chemotherapy in various solid tumors

233 (PB221): Therapeutic targeting of NRF2 increases sensitivity to chemotherapy in various solid tumors

NRF2 protects lung epithelial cells from wood smoke particle toxicity

Wildfire smoke is a potential source of oxidative stress in lung epithelial tissue. The response to oxidative stress is controlled by the transcription factor NRF2, which is the central regulator of antioxidant gene expression. If wood smoke particle (WSP) exposure induces reactive oxygen species (ROS) in epithelial cells, then NRF2 may protect against pathological conditions resulting from increased oxidative stress through changes in gene expression. We used two lung epithelial cell lines to test this hypothesis in vitro: A549, which harbor a mutation resulting in constitutive activation of NRF2, and BEAS-2B, which show limited NRF2 activity under basal conditions, but high inducibility during oxidative stress. In BEAS-2B cells, WSP exposure leads to increased cellular ROS, activation of NRF2, and upregulation of the NRF2 target genes NQO1, GCLM, and SRXN1. WSP exposure also increased ROS in A549 cells, although NRF2 activation and antioxidant gene upregulation were less robust as both were basally high in this cell line. Overall, the degree of ROS induction by WSP across cell lines is dependent upon NRF2 activity, and a similar pattern was observed for WSP cytotoxicity. WSP also sensitized both cell lines to the ferroptosis inducer erastin in a manner that is correlated with NRF2 activity. Knockout of NRF2 in A549 resulted in higher WSP-induced ROS generation, cytotoxicity, and erastin sensitivity. Taken together, these results suggest that NRF2 serves as a protective factor against wood smoke induced ROS and oxidative stress in lung epithelial cells.

Ginkgo Flavone Aglycone Ameliorates Atherosclerosis via Inhibiting Endothelial Pyroptosis by Activating the Nrf2 Pathway.

Natural antioxidants have been shown to be effective against atherosclerosis. Ginkgo flavone aglycone (GA) has strong antioxidant properties and can protect against endothelial damage. However, the mechanisms by which GA protects against atherosclerosis remain largely unexplored. This study hopes to find the anti-atherosclerotic mechanism of GA. ApoE-/- mice fed a high-fat diet were used for modeling atherosclerosis. The efficacy of GA on mice with atherosclerosis was evaluated based on the following indicators: Oil Red O staining, Masson staining, lipid content, and apoptosis. Transmission electron microscopy, Western blot, immunofluorescence staining, and propidium iodide staining were used to analyze the effects of GA on ox-LDL-treated human aortic endothelial cells. GA activated Nrf2 by promoting the nuclear translocation of Nrf2, thereby inhibiting endothelial pyroptosis. GA prevented endothelial pyroptosis suppressed oxidative stress, and inhibited the development of atherosclerosis in ApoE-/- mice fed high-fat diets. At the cellular level, GA suppressed ox-LDL-induced pyroptosis of HAECs by reducing reactive oxygen species (ROS) levels and inhibiting NLRP3 inflammasome. Furthermore, siRNA targeting Nrf2 or ML385, an Nrf2 inhibitor, reversed these effects. GA liberated Nrf2 from Keap1 sequestration, enhanced the nuclear translocation of Nrf2 and the transcription of downstream antioxidant proteins, reinforced the antioxidant defense system, and inhibited oxidative stress, thereby preventing endothelial cell pyroptosis, and attenuating the progression of atherosclerosis. This study indicated that GA mitigated endothelial pyroptosis by modulating Keap1/Nrf2 interactions, shedding light on the potential mechanisms underlying the protective effects of natural antioxidants against atherosclerosis.