Nrf2 Inhibitor Research Articles

Elevated GFI1 in Alveolar Macrophages Suppresses ACOD1 Expression and Exacerbates Lipopolysaccharide-Induced Lung Injury in Obesity.

To investigate the mechanisms behind the worsening of acute lung injury (ALI) in obesity, transcriptomic sequencing is performed, and significantly reduced mRNA levels of Aconitate Decarboxylase 1 (ACOD1) in the lung tissue of high-fat diet (HFD) mice are found. Clinical samples are collected, an ALI model is established in HFD mice, and both human and mouse samples are analyzed, revealing a significant decrease in ACOD1 expression in lung tissue and alveolar macrophages in obesity. Further in vivo and in vitro experiments show that ACOD1 knockdown worsens lung injury, inflammation, and oxidative stress, while ACOD1 overexpression alleviates these effects. Moreover, nuclear factor erythroid 2-related factor 2 (Nrf2) inhibition diminishes the protective effects of ACOD1 overexpression in ALI exacerbated by obesity. Additionally, in the context of obesity, growth factor independent 1 (GFI1) protein levels are elevated in alveolar macrophages, and its knockdown leads to upregulated ACOD1 expression. Therefore, this study suggests that ACOD1 downregulation in alveolar macrophages is a key factor in worsening ALI in obesity, likely driven by GFI1 upregulation.

The Aberrantly Expressed Nuclear Factor (Erythroid-derived 2)-Like 2 Participates in aGVHD by Modulating the Activation and Differentiation of CD4+ T Lymphocytes.

Current investigation indicates that nuclear factor (erythroid-derived 2)-like 2 (NRF2) possesses both proinflammatory and anti-inflammatory capabilities in T cells, yet its exact function in acute graft-versus-host disease (aGVHD) CD4+ T cells remains unexplored. This study aims to determine NRF2 levels within CD4+ T cells of patients with or without aGVHD and analyze the correlation between T-cell receptor activation and NRF2 expression. RNA sequencing was used to detect changes in the expression profile of CD4+ T cells after overexpression of NRF2, and functional enrichment analysis was performed on the sequencing results. Finally, after treating aGVHD CD4+ T cells with NRF2 inhibitor, the expression of related pathway molecules was detected. Our findings demonstrated a significant upregulation of NRF2 expression in CD4+ T cells from patients in the aGVHD group compared with patients in the non-aGVHD group, and its expression level is correlated with the severity of aGVHD. Additionally, T-cell receptor activation in CD4+ T cells elevates NRF2 expression. Postactivation of NRF2-inhibited CD4+ T cells, the expression levels of T-cell activation markers were notably lower than those in non-NRF2-inhibited CD4+ T cells. Sequencing analysis identified 904 genes that changed after NRF2 overexpression. These genes were categorized into 288 gene subsets, encompassing pathways such as T-cell receptor signaling transduction, Janus kinase 1/signal transducer and activator of transcription 1 (JAK1-STAT1) signaling, T helper cell 17 (Th17) cell differentiation, etc. Ultimately, treating CD4+ T cells of aGVHD patients with an NRF2 inhibitor led to a significant downregulation of JAK1-STAT1 signaling and Th17 cells. Elevated NRF2 expression in CD4+ T cells of patients with aGVHD initiates and exacerbates aGVHD by potentiating T-cell activation, amplifying JAK1/STAT1 signaling, and instigating Th17/regulatory T-cell ratio imbalance.

IRG1/itaconate enhances efferocytosis by activating Nrf2-TIM4 signaling pathway to alleviate con A induced autoimmune liver injury

Immune response gene 1 (IRG1) is highly expressed in mitochondria of macrophages in a pro-inflammatory state. IRG1 and its metabolites play important roles in infection, immune-related diseases and tumor progression by exerting resistance of pathogens, attenuating inflammation and producing antioxidant substances through various pathways and mechanisms. IRG1 deficiency aggravates liver injury. Efferocytosis is a vital mechanism for preventing the progression of inflammatory tissue damage. However, the mechanism by how IRG1/itaconate regulates efferocytosis in autoimmune hepatitis has yet to be fully understood. Therefore, we explored the influence of IRG1-/- on efferocytosis and its effects on regulating the nuclear factor erythroid 2-associated factor 2 (Nrf2)-T-cell immunoglobulin domain and mucin domain 4 (TIM4) pathway and autoimmune liver injury. An autoimmune hepatitis model was established by injecting Con A into wild-type and IRG1-/- mice via the tail vein. Liver injury and inflammatory response were assessed. The efferocytosis role of IRG1-/- macrophages and its potential regulatory mechanisms were also analysed. Exogenous 4-octyl itaconate (OI) supplementation promoted the expression of Nrf2 and TIM4 and restored IRG1-/- bone marrow-derived macrophage (BMDM) efferocytosis, whereas inhibition of Nrf2 mediated by ML385 led to impaired efferocytosis of BMDMs, decreased expression of TIM4, and aggravated liver inflammation injury. Additionally, after supplementing Nrf2-/- BMDMs with exogenous OI, we evaluated the changes in its efferocytosis effect, efferocytosis did not change, and the protective effect of OI disappeared. However, when TIM4 was blocked, the efferocytotic effect of BMDMs was attenuated, inflammatory liver injury and oxidative stress were aggravated. OI promoted the transformation of macrophages into M2 macrophages, and this was inhibited when TIM4 was blocked. To our best understanding, this is the initial exploration to show that TIM4, a downstream molecule of the IRG1/itaconate-Nrf2 pathway, regulates macrophage efferocytosis. These findings suggest a new mechanism and potential treatment for promoting the resolution of inflammation and efferocytosis in autoimmune hepatitis.

L-Glutamic Acid Alleviates Mastitis in Dairy Cows by Targeting the Sirt5/Nrf2/Prdx1 Signaling Axis and Mitochondrial Function.

Mastitis in dairy cows is an inflammatory disease that severely affects the health and lactation functions of dairy cows. Mitochondrial damage is closely related to the inflammatory response. How to effectively alleviate mitochondrial damage is the key to preventing and treating mastitis in dairy cows. In this study, we found elevated levels of inflammatory response and mitochondrial damage accompanied by reduced expression of Sirt5 (Sirtuin5) in cows with mastitis compared with healthy cows. This suggests that Sirt5 plays an important role in mastitis in dairy cows. Subsequently, we further analyzed mammary gland tissue from healthy and mastitis cows by untargeted metabolomics (LC-MS/MS) and screened for the differential metabolite l-glutamic acid (l-Glu). To further validate the effect of l-Glu on mastitis in dairy cows, we conducted a study using MAC-T cells. The results showed that l-Glu was able to ameliorate LPS-induced mitochondrial damage by activating Sirt5 and promoting mitochondrial fusion and the upregulation of mitochondrial membrane potential (MMP) levels. In contrast, l-Glu was unable to protect mitochondrial function after knocking down Sirt5. Furthermore, we found that l-Glu was able to upregulate the expression of nuclear factor E2-related factor (Nrf2) and peroxiredoxin 1 (Prdx1) in LPS-induced MAC-T cells, and promoted the entry of Nrf2 into the nucleus, which was reversed by knocking down Sirt5. Next, we further explored whether l-Glu alleviates mitochondrial damage through the Nrf2/Prdx1 signaling axis by using the Nrf2 inhibitor RA. The results showed that the use of RA promoted LPS-induced mitochondrial damage and blocked the protective effect of l-Glu on mitochondrial function. In conclusion, l-Glu ameliorates mitochondrial damage by targeting Sirt5 to activate the Nrf2/Prdx1 signaling axis and alleviate mastitis in dairy cows. This study provides a new target and theoretical basis for the clinical control of mastitis. l-Glu could be added as a dietary supplement to the diets of dairy cows and maintain mammary gland homeostasis, thereby protecting the health and economic value of dairy cows.

Mechanisms of Nrf2 suppression and Camkk1 upregulation in Echinococcus granulosus-induced bone loss.

Osteoclast differentiation is essential for maintaining bone metabolism, and its dysregulation, particularly in the context of Echinococcus granulosus (CE) infection, can lead to severe bone loss. This study explores a novel mechanism by which CE protoscolices (PSC) drive osteoclast differentiation through the inhibition of Nrf2, followed by the upregulation of Camkk1. Transcriptome sequencing revealed a significant down-regulation of Nrf2 in cells treated with PSC. This was confirmed by Western blot and Q-PCR assays showing reduced Nrf2 protein and gene levels. In vivo studies with Nrf2 knockout mice demonstrated that the absence of Nrf2 exacerbates bone loss induced by PSC in both the spine and lower limbs, as observed through Micro-CT imaging and TRAP staining.Further investigations identified Camkk1 as a key downstream target of Nrf2. Using high-throughput sequencing and CO-IP experiments, we established that Nrf2 directly interacts with and regulates Camkk1. Functional assays indicated that PSC-induced upregulation of Camkk1 is significantly enhanced by Nrf2 knockdown, while silencing Camkk1 alone inhibits osteoclast differentiation.The therapeutic potential of this pathway was evaluated by screening small molecule inhibitors of Camkk1, with Crenolani emerging as a potent compound. In vivo administration of Crenolani in PSC-treated mice significantly alleviated bone loss in a dose-dependent manner.These findings elucidate a crucial molecular mechanism in osteoclast differentiation driven by CE infection and propose a promising therapeutic strategy for combating CE-induced bone destruction. This study advances our understanding of bone.

Esketamine alleviates LPS-induced depression-like behavior by activating Nrf2-mediated anti-inflammatory response in adolescent mice.

The mechanisms underlying esketamine's therapeutic effects remain elusive. The study aimed to explore the impact of single esketamine treatment on LPS-induced adolescent depressive-like behaviors and the role of Nrf2 regulated neuroinflammatory response in esketamine-produced rapid antidepressant efficacy. Adolescent male C57BL/6J mice were randomly assigned to three groups: control, LPS, and LPS+esketamine (15mg/kg, i.p.). Depressive-like behaviors were evaluated via the OFT, NFST, and TST. Protein expression of Nrf2 and inflammatory cytokines, including TNF-α, IL-1β, and iNOS in the hippocampus and mPFC, were measured by western blot. Moreover, the Nrf2 inhibitor, ML385, was also applied in the current study. The depressive-like behaviors and the protein expression of Nrf2, TNF-α, IL-1β, and iNOS in mPFC and hippocampus were also measured. Additionally, the plasma's pro-inflammatory cytokines and anti-inflammatory cytokines were assessed using ELISA methods with or without ML385. A single administration of esketamine treatment alleviated the LPS-induced depressive-like behaviors. Esketamine increased the expression of Nrf2 and reduced the expression of the inflammatory cytokines, including TNF-α, IL-1β, and iNOS, in the mPFC and hippocampus. Notably, pharmacological inhibition of Nrf2 via ML385 administration abrogated the antidepressive-like behaviors and anti-inflammatory effects induced by esketamine. In the periphery, esketamine mitigated the LPS-induced elevation of pro-inflammatory cytokines, and the reduction of anti-inflammatory cytokines, and this effect was reversed by Nrf2 inhibition. Esketamine treatment exerts rapid antidepressant effects and attenuates neuroinflammation in LPS-induced adolescent depressive-like behaviors, potentially through the activation of Nrf2-mediated anti-inflammatory signaling.

REDD1 mediates HDM-induced nuclear-cytoplasmic translocation and release of IL-33 in airway epithelial cells by downregulating Nrf2

ObjectiveThis study aims to investigate whether REDD1 (Regulated in Development and DNA Damage Responses 1) mediates the nuclear-to-cytoplasmic translocation and release of IL-33 in airway epithelial cells induced by house dust mites (HDM).MethodsREDD1 expression levels in bronchial asthma patients were validated using public databases, followed by immunohistochemical analysis of REDD1 protein in airway epithelial cells from these patients. An asthma model was then established using HDM-induced 16HBE cell lines, with REDD1 gene knockout performed. The relationship between varying levels of REDD1 expression, Nrf2, and related inflammatory factors was assessed using Western blot and qPCR. To further investigate the role of the REDD1-Nrf2-IL-33 axis in the development of asthma, we employed Nrf2 activators and inhibitors to reassess the impact of REDD1 on IL-33.ResultsAt both mRNA and protein levels, we found that REDD1 was significantly overexpressed in samples from asthma patients (P < 0.05). In vitro, 24-hour exposure to HDM induced a notable nuclear-to-cytoplasmic translocation of IL-33 and increased its levels in the culture medium of 16HBE cells. In addition, HDM treatment significantly upregulated the expression of both REDD1 and Nrf2. Knockdown of REDD1 markedly suppressed HDM-induced IL-33 release and the expression of TNF-α, IL-6, and IL-1β, while enhancing Nrf2 expression. Moreover, treatment with the Nrf2 agonist curcumin inhibited HDM-induced nuclear-to-cytoplasmic translocation and extracellular secretion of IL-33, whereas the opposite effect was observed when using the Nrf2 antagonist ML385.ConclusionThis study reveals the crucial regulatory role of the REDD1-Nrf2-IL-33 axis in the pathological process of bronchial asthma. REDD1 modulates the expression of IL-33 and other inflammatory factors through the Nrf2 signaling pathway, thereby influencing the onset and progression of asthma.Clinical trial numberNot applicable.

Piceatannol-3'-O-β-D-glucopyranoside inhibits neuroexcitotoxicity and ferroptosis through NMDAR/NRF2/BACH1/ACSL4 pathway in acute ischemic stroke.

Neuronal protection is a well-established method of acute ischemic stroke (AIS) treatment. The pharmacodynamic effect of Piceatannol-3'-O-β-D-glucopyranoside (Chinese name: Hartigan, QZZG) on AIS has been reported, but the molecular mechanism of this effect remains unknown. The purpose of this study is to elucidate the pharmacodynamic effects and mechanisms of QZZG in the treatment of AIS. A combined network pharmacology and metabolomics approach was used to predict the key targets and pathways of QZZG in the treatment of AIS and to elucidate the mechanism of QZZG through experimental validation. In this study, QZZG improved histopathologic features and reduced infarct volume and neurologic deficit scores. Integrated network pharmacology and metabolomics revealed that QZZG may protect neurons by regulating glutamate and its receptors, and that glutamate is closely related to NMDAR1, NRF2, and Caspase-3. Pathway analysis results suggested that NMDAR-mediated Ca2+ inward flow is one of the critical pathways. In terms of neuroexcitotoxicity QZZG inhibited glutamate content, reduced Ca2+ inward flow, protected mitochondrial function, and reduced ROS, as well as being able to effectively inhibit the expression of NMDAR1, Caspase-3, Bax, and promote the expression of Bcl-2, NMDAR2A. In terms of ferroptosis QZZG promoted NRF2, HO-1, GPX4 and nuclear-NRF2, inhibited the expression of BACH1 and ACSL4, and suppressed Fe2+ accumulation and lipid peroxidation. Silencing of BACH1 resulted in elevated expression of NRF2 and decreased expression of ACSL4, which inhibited the sensitivity of neurons to ferroptosis. QZZG was able to further increase NRF2 expression under conditions of silencing BACH1. QZZG induced NRF2 and inhibited BACH1, ACSL4 was inhibited by ML385, and inhibition of NRF2 induced the expression of BACH1 and ACSL4, QZZG protects neurons in an NRF2-dependent manner. In summary, QZZG inhibited neuroexcitotoxicity and ferroptosis by regulating the NMDAR/NRF2/BACH1/ACSL4 pathway. The study provided a relatively novel perspective on the mechanism of traditional Chinese medicine (TCM) treatment of the disease.

Stigmasterol from Prunella vulgaris L. Alleviates LPS-induced mammary gland injury by inhibiting inflammation and ferroptosis.

Dairy mastitis, a prevalent condition affecting dairy cattle, represents a significant challenge to both animal welfare and the quality of dairy products. However, current treatment options remain limited. Stigmasterol (ST) is a bioactive component of Prunella vulgaris L. (PV) with various pharmacological functions such as anti-inflammatory and anti-oxidation. At present, the specific effects and underlying mechanisms of PV and ST on dairy mastitis are still not fully understood. The aim of this research was to evaluate the pharmacological effects of PV and its active component ST on lipopolysaccharide (LPS) -stimulated bovine mammary epithelial cells (BMECs) and a mouse mastitis model, and to elucidate the possible mechanisms of action. UPLC-Q-TOF-MS/MS was employed to identify the constituents of PV. BMECs and mice were used to establish in vitro and in vivo models of mastitis. Western Blotting, RT-qPCR, immunofluorescence and other techniques were used to explore the effects of PV and ST on inflammatory factors, blood-milk barrier integrity, ferroptosis related indicators and their potential molecular mechanisms. PV significantly attenuated the production of inflammatory mediators by LPS-stimulated BMECs. Subsequently, ST was found to be a potent anti-inflammatory agent in PV by inhibiting TLR4/NF-κB signaling pathway. This inhibition inhibits the myosin light chain (MLC)/MLC kinase signaling cascade and alleviates blood-milk barrier (BMB) disruption in BMECs. In addition, ferroptosis occurred in BMECs after LPS stimulation, and ST inhibited ferroptosis by stimulating Nrf2/GPX4 signaling pathway. Treatment of BMECs with the Nrf2 inhibitor ML385 significantly attenuated the therapeutic effect of ST. In vivo experiments further confirmed that both PV and ST attenuated LPS-induced breast tissue damage while reducing ferroptosis levels and restoring BMB. ST from PV exhibits substantial anti-inflammatory properties and is a promising candidate for the treatment of dairy mastitis.

Se-Methylselenocysteine Ameliorates DEHP-Induced Ferroptosis in Testicular Sertoli Cells via the Nrf2/GPX4 Axis.

Di (2-ethylhexyl) phthalate (DEHP) is an important plasticizer in industrial production, and its toxic effects on testes are widely recognized. Se-methylselenocysteine (SMC) is a major selenium compound found in selenium-rich plants, which possesses unique biological properties such as antioxidants. However, the effect of SMC on DEHP-induced testicular injury and the specific mechanism remains unknown. In this study, 50 mice were randomly divided into 5 groups and were given corn oil (Control), DEHP, low-dose SMC (L-SMC), moderate-dose SMC (M-SMC), or high-dose SMC (H-SMC). The sperm quality of the mice in each group was determined, and HE staining and transmission electron microscopy (TEM) were applied to observe testicular morphology, and testicular tissues were collected for the subsequent molecular biological analyses. The TM4 cell line was applied in vitro for mechanism validation. Our results showed that DEHP could lead to decreased sperm quality and blood-testis barrier damage in mice, which could be alleviated by SMC. Mitochondrial damage accompanied by accumulation of total iron content, MDA, and 4-HNE, as well as downregulation of antioxidants SOD, GSH, and GSH-Px were observed after DEHP treatment, which exhibited a typical ferroptosis feature. In vitro experiments confirmed that SMC promoted upregulation of GPX4 in TM4 cells and was able to alleviate DEHP metabolite MEHP-induced ferroptosis and promote the expression of cell junction key proteins ZO-1, Occludin, and Connexin 43, which could be inhibited by the GPX4 inhibitor RSL3 or the Nrf2 inhibitor ML385. Overall, the above results suggest that SMC ameliorates the DEHP-induced ferroptosis in testicular Sertoli cells, protects the blood-testis barrier, and prevents sperm aberrations via the Nrf2/GPX4 axis.

Redox control of NRF2 signaling in oocytes harnessing Porphyra derivatives as a toggle.

This study investigated the potential of Porphyra derivatives (PD), including Porphyra334, to activate the nuclear factor erythroid 2-related factor 2 (NRF2) pathway in porcine oocytes to enhance oocyte competency and intracellular networks. Conventional methods for manipulating mitochondrial functions and antioxidant pathways often rely upon genetic modifications that are impractical for direct application in humans. We hypothesized that PD serves as a natural regulator of the NRF2 pathway without requiring genetic intervention. To test this hypothesis, brusatol (Bru), a direct NRF2 inhibitor, was used to evaluate the specific role of PD in NRF2-mediated processes. The results demonstrated that PD significantly improved oocyte maturation, blastocyst formation, and mitochondrial function, including subsequent lipid metabolism. PD activates NRF2 and its downstream antioxidant response elements (AREs), whereas Bru inhibits these effects. Co-treatment with PD and Bru resulted in the partial recovery of NRF2 activity. These findings suggest that PD functions as a toggle for NRF2 activation, potentially offering a non-genetic strategy for enhancing oocyte quality and embryo development by modulating antioxidant mechanisms and mitochondrial functions. This study provides new avenues for investigating natural compounds in the context of reproductive biology and assisted reproductive technologies (ARTs).

Ursodeoxycholic acid protects against sepsis-induced acute kidney injury by activating Nrf2/HO-1 and inhibiting NF-κB pathway

BackgroundUrsodeoxycholic acid (UDCA), traditionally recognized for its hepatoprotective effects, has also shown potential in protecting kidney injury. This study aimed to evaluate the protective effects of UDCA against sepsis-induced acute kidney injury (AKI) and to elucidate the underlying mechanisms.MethodsSixty male C57BL/6 N mice were utilized to establish a sepsis-induced AKI model through intravenous injection of lipopolysaccharides (LPS, 10 mg/kg). UDCA (15, 30, and 60 mg/kg) was administered intraperitoneally once daily for 7 days before LPS injection. Kidney injury was evaluated by HE staining and biochemical markers, including serum creatinine (Cr), blood urea nitrogen (BUN), urinary protein, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), N-acetyl-β-D-glucosaminidase (NAG), and retinol binding protein (RBP). Oxidative stress parameters and nuclear factor erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1) pathway, pro-inflammatory cytokines and nuclear factor-kappa B (NF-κB) pathway were also evaluated. Additionally, HK-2 cells were treated with LPS in vitro, and cell viability and apoptosis were detected using CCK-8 kit and flow cytometer, respectively.ResultsUDCA significantly attenuated LPS-induced renal histopathological damage and improved renal function, as evidenced by reduction in serum Cr, BUN, and urinary protein levels. UDCA also up-regulated the protein expression of zonula occludens-1 (ZO-1) and Ezrin in the kidney, and reduced the urinary levels of NGAL, KIM-1, NAG, and RBP. Moreover, UDCA inhibited NF-κB p65 phosphorylation and reduced pro-inflammatory cytokines levels (TNF-α, IL-1β, and IL-6) in both serum and kidney. UDCA alleviated oxidative stress by activating the Nrf2/HO-1 pathway in the kidney. In vitro, UDCA reduced LPS-induced cell injury and apoptosis in HK-2 cells, with these protective effects being blocked by the Nrf2 inhibitor ML385.ConclusionsOur present study demonstrated that UDCA exerts protective effects against sepsis-induced AKI by attenuating oxidative stress and inflammation, primarily through the activation of the Nrf2/HO-1 pathway and inhibition of the NF-κB pathway. These findings highlight the therapeutic potential of UDCA in preventing sepsis-induced AKI.

Liposomes-Loaded miR-9-5p Alleviated Hypoxia-Ischemia-Induced Mitochondrial Oxidative Stress by Targeting ZBTB20 to Inhibiting Nrf2/Keap1 Interaction in Neonatal Mice.

Aims: Hypoxia ischemia (HI) is a leading cause of cerebral palsy and long-term neurological sequelae in infants. Given that mitochondrial dysfunction in neurons contributes to HI brain damage, this study aimed to investigate the regulatory role of miR-9-5p in mitochondrial function following HI injury. Results: Overexpression of miR-9-5p in HI mice or H2O2-exposed PC12 cells suppressed neuronal injury, associated with increased mitochondrial copy number, normalizing mitochondrial membrane potential, improved nuclear factor-erythroid factor 2-related factor 2 (Nrf2) activation, and downregulation of Keap1. This was mediated, in part, through the ability of this miR-9-5p to bind and regulate the transcriptional activity of zinc finger and BTB domain-containing protein 20 (ZBTB20). Further study suggested that the knockdown of ZBTB20 exerts neuroprotection by inhibiting Nrf2/Keap1 interaction to promote the translocation of Nrf2 from the cytoplasm to the nucleus and the consequent expression of antioxidant proteins. Notably, the protective effects of miR-9-5p overexpression against HI-induced mitochondrial damage were reversed by the Nrf2 inhibitor ML385. Finally, the utilization of liposomes for the delivery of miR-9-5p (miR-9-5p@Lip) presents a promising therapeutic strategy for the treatment of HI injury. Innovation: miR-9-5p is a potential therapeutic agent for ischemic stroke through its modulation of the ZBTB20/Nrf2/Keap1 signaling pathway, influencing mitochondrial function and antioxidant response. Furthermore, the use of liposomal delivery for miR-9-5p offers a promising therapeutic strategy for HI injury. Conclusion: Overexpression of miR-9-5p protects against cerebral HI injury by modulating mitochondrial function through the ZBTB20/Nrf2/Keap1 signaling pathway. Antioxid. Redox Signal. 00, 000-000.

Ligustrazine hydrochloride Prevents Ferroptosis by Activating the NRF2 Signaling Pathway in a High-Altitude Cerebral Edema Rat Model

High-altitude cerebral edema (HACE) is a disorder caused by low pressure and hypoxia at high altitudes. Nevertheless, as of now, there is still a scarcity of safe and effective prevention and treatment methods. The active component of Ligusticum Chuanxiong, namely Ligustrazine hydrochloride (LH), has shown potential in the prevention and treatment of HACE due to its anti-inflammatory, antioxidant, and neuroprotective effects in nervous system disorders. Consequently, the potential protective effect of LH on HACE and its mechanism still need to be further explored. Prior to modeling, 90 male Sprague-Dawley rats were pretreated with different doses of drugs, including LH (100 mg/kg and 50 mg/kg), dexamethasone (4 mg/kg), and ML385 (30 mg/kg). Subsequently, the pretreated rats were placed in a low-pressure anoxic chamber simulating a plateau environment to establish the rat HACE model. The effects and mechanisms of LH on HACE rats were further elucidated through determination of brain water content, HE staining, ELISA, immunofluorescence, molecular docking, molecular dynamics simulation, western blot, and other techniques. The results showed, first of all, that LH pretreatment can effectively reduce brain water content; down-regulate the expression of AQP4, HIF-1α, and VEGF proteins; and alleviate damage to brain tissue and nerve cells. Secondly, compared with the HACE group, LH pretreatment can significantly reduce MDA levels and increase GSH and SOD levels. Additionally, LH decreased the levels of inflammatory factors IL-1β, IL-6, and TNF-α; reduced total iron content in brain tissue; increased the expression of ferroptosis-related proteins such as SLC7A11, GPX4, and FTH1; and alleviated ferroptosis occurrence. Molecular docking and molecular dynamics simulations show that LH has a strong binding affinity for NRF2 signaling. Western blot analysis further confirmed that LH promotes the translocation of NRF2 from the cytoplasm to the nucleus and activates the NRF2 signaling pathway to exert an antioxidant effect. The NRF2 inhibitor ML385 can reverse the anti-oxidative stress effect of LH and its protective effect on HACE rat brain tissue. In summary, LH may have a protective effect on HACE rats by activating the NRF2 signaling pathway, inhibiting ferroptosis, and resisting oxidative stress.

Mechanistic insights of methylcinnamate in improving oxidative stress and inflammation in acetaminophen-induced hepatotoxic mice by upregulating Nrf2 pathway.

Methylcinnamate (MC), a safe flavoring agent naturally found in Occimum basilicum L. is reported to have an anti-inflammatory responses in various disease models. Acetaminophen (APAP) toxicity is a significant contributor to acute liver injury, which leads to oxidative stress and inflammation. The transcriptional factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulated the cellular defense mechanisms aid to antioxidant response facilitation and reduction in inflammation against various disorders. This study evaluated the protective effects of MC in APAP-induced hepatotoxicity in mice and its anti-oxidant, anti-inflammatory, and Nrf2 mechanisms were studied. In-vitro 2,2-diphenyl-1-picrylhydrazyl assay showed the antioxidant capacity of MC. Mice were pretreated with MC (25, 50, 75, and 100mg/kg) orally for 7 days. After a fasting period of 16h, hepatotoxicity was induced by injecting APAP 300mg/kg intraperitoneal on day 7. Liver profile, oxidative test, and histopathological changes were studied. Gene expression of interlukin-1β (IL-1β), interlukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), cytochrome P450 2E1 (CYP2E1), Nrf2, and NAD(P)H dehydrogenase (quinone) 1 (NQO-1) were estimated by real time quantitative polymerase chain reaction (RT-qPCR). IL-1β, IL-6, and TNF-α concentrations were also analyzed by enzyme-linked immunosorbent assay (ELISA). The MC treatment showed a notable reduction in alanine transaminase, aspartate aminotransferase and alkaline phosphatase activities, and total bilirubin level of serum. Moreover, MC significantly attenuated oxidative stress by rising the antioxidant enzymes catalase, glutathione, and superoxide dismutase and reducing the malondialdehyde and nitric oxide levels in the liver. Furthermore, MC successfully mitigated the levels of IL-1β, IL-6, and TNF-α, which were estimated through RT-qPCR and ELISA. The RT-qPCR revealed a CYP2E1 enzyme inhibition and significant upregulation of hepatic Nrf2 and NQO-1 levels after MC therapy. Histopathological analysis showed improvement in liver injury within the MC treatment groups. It was concluded from this study that pretreatment of MC had successfully protected the liver through anti-inflammatory, anti-oxidant activity upon subsequent activation of Nrf2.

Ursonic Acid Ameliorates H2O2-Induced Oxidative Damage in PC12 Cells and Prolonged the Lifespan in C. elegans by Activating MAPKs/Nrf2/HO-1 Signaling Pathway.

Growing evidence suggests that plant compounds are emerging as a tremendous source for slowing the onset and progression of Alzheimer's disease (AD). Ursonic acid (UNA) is a naturally occurring pentacyclic triterpenoid with some hypoglycemic, anticancer, and antiinflammatory activities. However, the pharmacological effects of UNA on AD are still unknown. In the present experiments, the effects and mechanisms of UNA on AD were firstly explored by H2O2-induced PC12 cells and Aβ1-42-induced AD model of Caenorhabditis elegans (C. elegans). The results showed that UNA increased the cell viability and the level of mitochondrial membrane potential and reversed apoptosis in H2O2-induced PC12 cells, and Nrf2 and HO-1 were involved in this process. UNA also decreased the phosphorylation of related proteins in the MAPK signaling pathway. Meanwhile, we found that UNA upregulated cellular catalase levels and decreased ROS production. Besides, UNA could activate the Nrf2 /HO-1 signaling pathway and upregulate its protein expression under oxidative stress conditions, whereas Nrf2 and HO-1 inhibitors partially eliminated the protective ability of UNA. The results of in vivo experiments showed that UNA prolonged the lifespan and enhanced the health parameters of AD C. elegans and reduced Aβ1-42-induced neurotoxicity and ROS levels. Moreover, UNA increased GFP-tagged LGG-1 puncta in DA2123 C. elegans. Further mechanistic studies suggested that the protection of UNA on AD C. elegans may be through modulation of the MAPKs/Nrf2/HO-1 pathway. These results highlight the neuroprotective potential of UNA and suggest that UNA may be an effective therapeutic agent for alleviating AD.

Macranthoside B Suppresses the Growth of Adenocarcinoma of Esophagogastric Junction by Regulating Iron Homeostasis and Ferroptosis through NRF2 Inhibition.

Macranthoside B (MB) is a saponin compound extracted from hon-eysuckle that has been reported to exhibit significant medicinal values, particularly anti-tumor activities. This study aimed to evaluate the anticancer efficacy of MB in treating adenocarci-noma of the esophagogastric junction (AEG) and elucidate its underlying mechanisms. Three AEG cell lines and normal gastric epithelial cells were used to assess the an-ticancer activity of MB in vitro. A series of experiments, including RNA sequencing (RNA-seq) analysis, transmission electron microscopy (TEM), immunofluorescence, and western blot assay, were conducted to validate the molecular mechanisms by which MB may mediate these physiological changes. Finally, we used shRNA assays to silence the key gene driving these changes and examined the expression of molecules involved in the affected pathways. MB exhibited significant anti-AEG cell activity with IC50 values ranging from 9.5 to 12.7 μM. RNA-seq results indicated that MB treatment in AEG cells significantly altered mRNA levels of autophagy- and ferroptosis-related genes. Further experiments revealed that MB treatment led to the up-regulation of lipid reactive oxygen species (Lip-ROS), oxidative stress-related pathway genes, and LC3B-labeled autophagic vesicles in AEG cells. Moreover, MB mediated NCOA4-dependent ferritinophagy, disrupting iron homeostasis and causing subsequent ferroptosis. We further confirmed that the intrinsic connection between autophagy and ferroptosis was due to the inhibition of NRF2 by MB. The inhibition of NRF2 by MB triggered transcriptional repression of its downstream effector molecules HERC2 and VAMP8, thus stabilizing NCOA4. This study demonstrated MB to inhibit AEG cell growth by regulating iron ho-meostasis and inducing ferroptosis through the inhibition of NRF2, providing a basis for the development of novel drugs for AEG treatment.

Astaxanthin-loaded polylactic acid-glycolic acid nanoparticles alleviates atherosclerosis by suppressing macrophage ferroptosis via the NRF2/SLC7A11/GPX4 pathway.

Astaxanthin (ASX), a fat-soluble carotenoid mainly sourced from Haematococcus pluvialis, shows promise for clinical applications in chronic inflammatory diseases. This study investigates whether ASX can mitigate atherosclerosis (AS) by modulating macrophage ferroptosis and provides astaxanthin-loaded polylactic acid-glycolic acid nanoparticles (ASX-PLGA NPs) as comparison. ApoE-/- mice were fed a high-fat diet with ASX or statin intervention. Plaque area, lipid aggregation, collagen content, and ferroptosis-related indicators were assessed. Moreover, ASX-PLGA NPs were synthesized and characterized and were used to pretreat macrophages induced with oxidized low-density lipoprotein (ox-LDL). Indicators linked to ferroptosis and oxidative stress were detected. Finally, the expression of nuclear factor erythroid -related factor 2 (NRF2) was evaluated. ASX intervention significantly delayed the progression of AS plaques, characterized by reductions in plaque area and increased collagen fibers. The observed improvements in AS were consistent with statins. ASX-PLGA NPs demonstrate good safety and stability and have better therapeutic effects than ASX alone. Indicators linked to ferroptosis and oxidative stress were significantly improved in groups containing ASX in vivo and vitro. Additionally, ASX facilitated the nuclear translocation of NRF2, which could be attenuated with ML385, a specific inhibitor of NRF2. ASX-PLGA NPs have better therapeutic effects than ASX alone. The regulation of NRF2/SLC7A11/GPX4 represents a novel mechanism by which ASX can counteract ferroptosis and impede AS progression.

Identification of narciclasine as a novel NRF2 inhibitor

Cancer genome sequencing studies have identified somatic mutations in the KEAP1/NRF2 pathway. In an effort to identify novel NRF2 small molecule inhibitor(s), we have screened a natural compound library comprising 1330 chemicals in A549-ARE-GFP-luciferase cells and identified that narciclasine significantly inhibits NRF2-dependent luciferase activity. Narciclasine suppressed the expression of NRF2 and NRF2 target genes, caused significant oxidative stress, and sensitized cisplatin-mediated apoptosis in A549 cells. In addition, we have observed that WD Repeat Domain 43 (WDR43) serves as a direct target of narciclasine for the inhibition of NRF2 as narciclasine binds to recombinant WDR43 in vitro and silencing WDR43 attenuated the inhibition of NRF2 by narciclasine in A549 cells. Finally, we observed that administration of narciclasine significantly decreased the growth of A549 xenografts. Together, our results demonstrate that the inhibition of NRF2 by narciclasine is mediated by WDR43 and future studies are necessary to elucidate the exact mechanism of how WDR43 mediates the inhibition of NRF2 by narciclasine.

Tangeretin alleviates sepsis-induced acute lung injury by inhibiting ferroptosis of macrophage via Nrf2 signaling pathway

BackgroundSepsis-induced acute lung injury (ALI) is a severe clinical condition accompanied with high mortality. Tangeretin, which is widely found in citrus fruits, has been reported to exert antioxidant and anti-inflammatory properties. However, whether tangeretin protects against sepsis-induced ALI and the potential mechanisms remain unclear.MethodsWe established an ALI model via intraperitoneally injected with 5 mg/kg lipopolysaccharides (LPS) for 12 h. Tangeretin was applied intraperitoneally 30 min before LPS treatment. Dexamethasone (Dex) was used as a positive control. Hematoxylin and eosin (HE) staining and protein content in bronchoalveolar lavage fluid (BALF) were determined to detect the degree of lung injury. RNA-seq was also applied to explore the effect of tangeretin on ALI. In vitro, RAW264.7 were treated with Nrf2 siRNA, the expression of ferroptosis-associated biomarkers, including glutathione peroxidase 4 (GPX4) and prostaglandin-endoperoxide synthase 2 (PTGS2) were assessed. Glutathione (GSH), malondialdehyde (MDA) levels, reactive oxygen species (ROS) and inflammatory factors were also determined both in vivo and in vitro. Furthermore, mice were treated with an Nrf2 inhibitor (ML385) to verify the mechanism of tangeretin in inhibiting sepsis-induced lung injury and ferroptosis. Data were analyzed using one way analysis of variance or two-tailed unpaired t tests.ResultsOur study demonstrated that tangeretin significantly alleviated lung injury, reversed the LPS-induced reduction in GPX4 and GSH, and mitigates the elevation of PTGS2 and MDA levels. Tangeretin also reduced 4-HNE and iron levels. Besides, the levels of LPS-stimulated inflammatory factors IL-6, IL-1β and TNF-α were also decreased by tangeretin. RNA-seq and bioinformatics analysis demonstrated that tangeretin inhibited inflammatory response. Mechanistically, we identified that tangeretin inhibited the GPX4-dependent lipid peroxidation through activation of Nrf2. The silence of Nrf2 abolished the inhibitory effect of tangeretin on oxidative stress, inflammatory response and ferroptosis in RAW264.7 cells. Additionally, all the protective effects of tangeretin on ALI were abolished in Nrf2 inhibitor-treated mice.ConclusionWe identified that ferroptosis as a critical mechanism contributing to sepsis-induced ALI. Tangeretin, a promising therapeutic candidate, effectively mitigates ALI through inhibiting ferroptosis via upregulating Nrf2 signaling pathway.