Nrf2 Activation Research Articles

Role of Nrf2 in Epilepsy Treatment.

Oxidative stress is a consequence of the disruption of the balance between the generation of reactive nitrogen and oxygen species and the biological system's ability to neutralize those reactive products. Oxidative stress is involved in the generation of many disorders, including epilepsy, which is a prevalent chronic neurological disease that affects the lives of millions of people around the world. Epilepsy is characterized by unforeseeable and repeated seizures that can be very disturbing. Studies have reported that oxidative stress occurs before and after seizures. A transcription factor named Nuclear factor erythroid-derived 2-related factor 2 (Nrf2) controls genes related to the induction of oxidative stress and defends cells against oxidative stress. The Nrf2 protein has seven different domains, ranging from Neh1 to Neh7. Each domain is responsible for a distinctive function of this protein. Keap1 binds to Nrf2, but during oxidative stress, Nrf2 detaches from the Keap1 protein, moves to the nucleus, and binds to DNA. The result of this translocation and binding is the initiation of transcription of detoxifying genes to control the harmful effects of oxidative stress. There is some evidence of oxidative stress involvement in epilepsy. In this review, we have listed potential Nrf2-related therapeutic targets for treating and controlling epilepsy, such as Berberis alkaloids, pentoxifylline, lovastatin, progesterone, and chrysin nanoparticles. These activators were tested in animals (in vivo) and cells (in vitro), and most of these experiments showed promising results in different epilepsy models. Finally, the results have suggested that the activation of Nrf2 can be an option for controlling epilepsy.

CBR-470-1 protects against cardiomyocyte death in ischaemia/reperfusion injury by activating the Nrf2–GPX4 cascade

Cardiac ischaemia/reperfusion (I/R) impairs mitochondrial function, resulting in excessive oxidative stress and cardiomyocyte ferroptosis and death. Nuclear factor E2-related factor 2 (Nrf2) is a key regulator of redox homeostasis and has cardioprotective effects against various stresses. Here, we tested whether CBR-470-1, a noncovalent Nrf2 activator, can protect against cardiomyocyte death caused by I/R stress. Compared with vehicle treatment, the administration of CBR-470-1 (2 mg/kg) to mice significantly increased Nrf2 protein levels and ameliorated the infarct size, the I/R-induced decrease in cardiac contractile performance, and the I/R-induced increases in cell apoptosis, ROS levels, and inflammation. Consistently, the beneficial effects of CBR-470-1 on cardiomyocytes were verified in a hypoxia/reoxygenation (H/R) model in vitro, but this cardioprotection was dramatically attenuated by the GPX4 inhibitor RSL3. Mechanistically, CBR-470-1 upregulated Nrf2 expression, which increased the expression levels of antioxidant enzymes (NQO1, SOD1, Prdx1, and Gclc) and antiferroptotic proteins (SLC7A11 and GPX4) and downregulated the protein expression of p53 and Nlrp3, leading to the inhibition of ROS production and inflammation and subsequent cardiomyocyte death (apoptosis, ferroptosis and pyroptosis). In summary, CBR-470-1 prevented I/R-mediated cardiac injury possibly through inhibiting cardiomyocyte apoptosis, ferroptosis and pyroptosis via Nrf2-mediated inhibition of p53 and Nlrp3 and activation of the SLC7A11/GPX4 pathway. Our data also highlight that CBR-470-1 may serve as a valuable agent for treating ischaemic heart disease.

NRF2 signaling plays an essential role in cancer progression through the NRF2-GPX2-NOTCH3 axis in head and neck squamous cell carcinoma

The activation of nuclear factor erythroid 2–related factor 2 (NRF2) has been observed in various cancers. Yet its exact contribution to the development of head and neck squamous cell carcinoma (HNSCC) remains undetermined. We previously found that NRF2 signaling is critical for the differentiation of squamous basal progenitor cells, while disruption of NRF2 causes basal cell hyperplasia. In this study, we revealed a correlation between elevated NRF2 activity and poor outcomes in HNSCC patients. We demonstrated that NRF2 facilitates tumor proliferation, migration, and invasion, as evidenced by both in vitro and in vivo studies. Significantly, NRF2 augments the expression of the antioxidant enzyme GPX2, thereby enhancing the proliferative, migratory, and invasive properties of HNSCC cells. Activation of GPX2 is critical for sustaining cancer stem cells (CSCs) by up-regulating NOTCH3, a key driver of cancer progression. These results elucidate that NRF2 regulates HNSCC progression through the NRF2-GPX2-NOTCH3 axis. Our findings proposed that pharmacological targeting of the NRF2-GPX2-NOTCH3 axis could be a potential therapeutic approach against HNSCC.

REDOX SIGNALLING IN THE PANCREAS IN HEALTH AND DISEASE.

This review addresses oxidative stress and redox signaling in the pancreas under physiological conditions as well as in acute pancreatitis, chronic pancreatitis, pancreatic cancer, and diabetes. Physiological redox homeodynamics is maintained mainly by NRF2/KEAP1, NF-κB, protein tyrosine phosphatases, peroxisome proliferator-activated receptor-γ co-activator 1α (PGC1α), and normal autophagy. Depletion of reduced glutathione in the pancreas is a hallmark of acute pancreatitis and is initially accompanied by disulfide stress, which is characterized by protein cysteinylation without increased glutathione oxidation. A cross-talk between oxidative stress, MAPKs, and NF-κB amplifies the inflammatory cascade, acting PP2A and PGC1α as key redox regulatory nodes. In acute pancreatitis, nitration of cystathionine-β synthase causes blockade of the trans-sulfuration pathway leading to increased homocysteine levels, whereas p53 triggers necroptosis in the pancreas through downregulation of sulfiredoxin, PGC1α, and peroxiredoxin 3. Chronic pancreatitis exhibits oxidative distress mediated by NADPH oxidase 1 and/or CYP2E1, which promotes cell death, fibrosis, and inflammation. Oxidative stress cooperates with mutant KRAS to initiate and promote pancreatic adenocarcinoma. Mutant KRAS increases mitochondrial ROS, which trigger acinar-to-ductal metaplasia and progression to PanIN. ROS are maintained at sufficient level to promote cell proliferation, whilst avoiding cell death or senescence through formation of NADPH and GSH, and activation of NRF-2, HIF-1/2α, and CREB. Redox signalling also plays a fundamental role in differentiation, proliferation, and insulin secretion of β-cells. However, ROS overproduction promotes β-cell dysfunction and apoptosis in type 1 and type 2 diabetes.

Discovery and Optimization of a Series of Vinyl Sulfoximine-Based Analogues as Potent Nrf2 Activators for the Treatment of Multiple Sclerosis.

Multiple sclerosis (MS) is an immune-mediated neurodegenerative disease of the central nervous system (CNS), which leads to demyelination, axonal loss, and neurodegeneration. Increased oxidative stress and neurodegeneration have been implicated in all stages of MS, making neuroprotective therapeutics a promising strategy for its treatment. We previously have reported vinyl sulfones with antioxidative and anti-inflammatory properties that activate nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that induces the expression of cytoprotective genes against oxidative stress. In this study, we synthesized vinyl sulfoximine derivatives by modifying the core structure and determined therapeutic potential as Nrf2 activators. Among them, 10v effectively activated Nrf2 (EC50 = 83.5 nM) and exhibited favorable drug-like properties. 10v successfully induced expression of Nrf2-dependent antioxidant enzymes and suppressed lipopolysaccharide (LPS)-induced inflammatory responses in BV-2 microglial cells. We also confirmed that 10v effectively reversed disease progression and attenuated demyelination in an experimental autoimmune encephalitis (EAE) mouse model of MS.

Harmaline attenuates chemotherapy-induced peripheral neuropathy: Modulation of Nrf-2 pathway and NK-1 receptor signaling

Peripheral neuropathy, resulting from damage to peripheral nerves, manifests as weakness, numbness, and pain, primarily affecting extremities and significantly impairing quality of life, especially in the elderly. Current treatments often entail severe side effects, necessitating the exploration of alternative therapies. Harmaline, a β-carboline alkaloid derived from Peganum harmala, exhibits promising antioxidant and anti-inflammatory properties. This study aimed to assess the efficacy of harmaline in a vincristine-induced mouse model of peripheral neuropathy. Swiss albino mice received vincristine (0.1 mg/kg, i.p.) for 10 days to induce neuropathy. Harmaline (5 and 10 mg/kg, i.p.) was administered 30 min before vincristine and continued until day 14 to evaluate its protective effects. Behavioral assessments were conducted on days 7 and 14. Vincristine treatment significantly heightened sensitivity to cold, measured by cold plate and acetone drop tests, and to heat, assessed via the hot plate test, while also impairing motor coordination. Biochemical analyses revealed decreased levels of GSH and Nrf-2, alongside elevated TBARS and IL-1β levels in sciatic nerve tissue. Harmaline administration markedly alleviated both behavioral and biochemical alterations induced by vincristine, with the 10 mg/kg dose exhibiting the most pronounced effects. Notably, harmaline treatment elevated GSH and Nrf-2 levels while reducing TBARS and IL-1β. Furthermore, substance-P treatment reversed the protective effects of harmaline, implicating the NK-1 receptor in its mechanism of action. In conclusion, harmaline demonstrates significant potential in mitigating vincristine-induced peripheral neuropathy by reducing oxidative stress through Nrf-2 activation and lowering IL-1β levels, likely via NK-1 receptor inhibition.

P53-dependent crosstalk between DNA replication integrity and redox metabolism mediated through a NRF2-PARP1 axis.

Mechanisms underlying p53-mediated protection of the replicating genome remain elusive, despite the quintessential role of p53 in maintaining genomic stability. Here, we uncover an unexpected function of p53 in curbing replication stress by limiting PARP1 activity and preventing the unscheduled degradation of deprotected stalled forks. We searched for p53-dependent factors and elucidated RRM2B as a prime factor. Deficiency in p53/RRM2B results in the activation of an NRF2 antioxidant transcriptional program, with a concomitant elevation in basal PARylation in cells. Dissecting the consequences of p53/RRM2B loss revealed a crosstalk between redox metabolism and genome integrity that is negotiated through a hitherto undescribed NRF2-PARP1 axis, and pinpoint G6PD as a primary oxidative stress-induced NRF2 target and activator of basal PARylation. This study elucidates how loss of p53 could be destabilizing for the replicating genome and, importantly, describes an unanticipated crosstalk between redox metabolism, PARP1 and p53 tumor suppressor pathway that is broadly relevant in cancers and can be leveraged therapeutically.

The Nrf2-HO-1 system and inflammaging.

Nrf2 is a master transcriptional regulator of a number of genes involved in the adaptive response to oxidative stress. Among the genes upregulated by Nrf2, heme oxygenase-1 (HO-1) has received significant attention, given that the products of HO-1-induced heme catabolism have well established antioxidant and anti-inflammatory properties. This is evidenced in numerous models of inflammatory and autoimmune disease whereby induction of HO-1 expression or administration of tolerable amounts of HO-1 reaction products can ameliorate disease symptoms. Unsurprisingly, Nrf2 and HO-1 are now considered viable drug targets for a number of conditions. In recent years, the term 'inflammaging' has been used to describe the low-grade chronic inflammation observed in aging/aged cells. Increased oxidative stress is also a key factor associated with aging and there is convincing evidence that Nrf2, not only declines with age, but that Nrf2 and HO-1 can reduce cellular senescence and the senescence-associated secretory phenotype (SASP) which is now considered an underlying driver of age-related inflammatory disease. In this review, we describe the role of oxidative stress in 'inflammaging' and highlight the potential anti-aging properties of the Nrf2-HO-1 system. We also highlight established and newly emerging Nrf2 activators and their therapeutic application in age-related disease.

NRF2 Activation by AR-20007 Preserves Renal Tubular Epithelial Cells from Antimycin A-Induced Cell Death via Glutathione Metabolism Regulation.

Oxidative stress plays a crucial role in the development and progression of various kidney diseases. Nuclear factor erythroid 2-related factor 2 (NRF2) is the primary transcription factor that protects cells from oxidative stress by regulating cytoprotective genes including those involved in the antioxidant glutathione (GSH) pathway. GSH maintains cellular redox status and affects redox signaling, cell proliferation, and cell death. Antimycin A, an inhibitor of complex III of the electron transport chain, causes oxidative stress and reduces GSH levels. In this study, we induced mitochondrial damage in rat renal proximal tubular cells using antimycin A and investigated cellular viability and levels of NRF2 and GSH. Treatment with antimycin A altered the expression of antioxidant genes, including reduction in the transcription of glutathione-cysteine ligase subunits (Gclc and Gclm) and glutathione reductase (Gsr1), followed by a reduction in total GSH content with a concomitant decrease in NRF2 protein expression. AR-20007, previously described as an NRF2 activator, stabilizes and increases NRF2 protein expression in cells. By stimulating NRF2, AR-20007 increased the expression of antioxidant and detoxifying enzymes, thereby enhancing protection against oxidative stress induced by antimycin A. These data suggest that NRF2 activation effectively inhibits antimycin A-induced oxidative stress and that NRF2 may be a promising therapeutic target for preventing cell death during acute kidney injury.

State-of-the-art Nrf2 Inhibitors: Therapeutic Opportunities in Non-cancer Diseases.

Nrf2is a cytoprotective transcription factor that induces the transcription of genes responsible for the cell's response to oxidative stress. While Nrf2 activation has led to the development of clinically relevant therapeutics, the oncogenic role of Nrf2 in the proliferation of cancer cells has underscored the complex nature of Nrf2 and the necessity for the development of Nrf2 inhibitors. Although the application of Nrf2 inhibitors appears limited as anticancer agents, recent studies have begun to pinpoint the impairment of autophagy in diseases as a cellular marker that shifts Nrf2 from a protective to a deleterious state. Therefore, the cytoplasmic accumulation of Nrf2 can lead to the accumulation of lipid hydroperoxides and, ultimately, to ferroptosis. However, some studies aimed at elucidating the role of Nrf2 in non-cancer diseases have yielded conflicting results, attributed to differences in approaches used to inhibit or activate Nrf2, as well as variations indisease models. Overall, these results highlight the necessity for a deeper evaluation of Nrf2's role in diseases, especially chronic diseases. In this review, we discuss diseases where Nrf2 inhibition holds potential for beneficial therapeutic effects and summarize recently reported Nrf2 inhibitors exploiting medicinal chemistry approaches suitable for targeting transcription factors like Nrf2.

Low-Protein Diet Inhibits the Synovial Tissue Macrophage Pro-Inflammatory Polarization Via NRF2/SIRT3/SOD2/ROS Pathway in K/BxN Rheumatoid Arthritis Mice.

Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by pain, swelling, stiffness, and impaired function. Attenuating inflammation is a crucial objective in RA management. Diet and nutrition are believed to influence RA symptomatology, with a low-protein diet being one potential nutritional strategy, although its underlying mechanisms remain to be fully elucidated. In this research, serum derived from arthritic transgenic K/BxN mice was administered to naive mice to establish a K/BxN rheumatoid arthritis model. Physiological assessments and histological staining were performed to evaluate joint pathology. (Enzyme-linked immunosorbent assay) ELISA was used to measure inflammatory cytokines. Flow cytometry and immunofluorescence were applied to characterize macrophage phenotypes. Transcriptomic analysis elucidated molecular pathways under the effect of a low-protein diet and verified by immunoblotting. Mitochondrial reactive oxygen species (ROS) was detected by Mito-SOX. Protein expression was silenced through the application of siRNA transfection. Our results indicate that a low-protein diet significantly alleviates disease symptoms and decreases pro-inflammatory cytokine levels in synovial fluid. Furthermore, this dietary intervention inhibits M1 macrophage polarization while promoting a shift towards the M2 phenotype. Transcriptomic analysis revealed that the beneficial effects of the low-protein diet in alleviating rheumatoid arthritis are closely linked to the NRF2 pathway. In vitro, low protein treatment can promote the activity of NRF2 via inhibiting the ubiquitin mediated proteolysis and activate the NRF2/SIRT3/SOD2 pathway to inhibit the production of ROS, which will further inhibit the M1 macrophage polarization. NRF2 knockdown can abolish the effects of low-protein treatment, indicating that the inhibition of M1 polarization and the anti-inflammatory response induced by low-protein treatment are dependent on NRF2. In summary, our findings propose that low-protein diet can inhibit synovial macrophage M1 polarization via activating NRF2/SIRT3/SOD2 pathway to reduce mitochondrial ROS production. This mechanism effectively decreases synovial inflammation and alleviates RA symptoms.

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

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

Modulation of osteoblastogenesis by NRF2: NRF2 activation suppresses osteogenic differentiation and enhances mineralization in human bone marrow-derived mesenchymal stromal cells.

Mesenchymal stromal stem cells (MSCs) or skeletal stem cells (SSCs) play a major role in tissue repair due to their robust ability to differentiate into osteoblasts, chondrocytes, and adipocytes. Complex cell signaling cascades tightly regulate this differentiation. In osteogenic differentiation, Runt-related transcription factor 2 (RUNX2) and ALP activity are essential. Furthermore, during the latter stages of osteogenic differentiation, mineral formation mediated by the osteoblast occurs with the secretion of a collagenous extracellular matrix and calcium deposition. Activation of nuclear factor erythroid 2-related factor 2 (NRF2), an important transcription factor against oxidative stress, inhibits osteogenic differentiation and mineralization via modulation of RUNX2 function; however, the exact role of NRF2 in osteoblastogenesis remains unclear. Here, we demonstrate that NRF2 activation in human bone marrow-derived stromal cells (HBMSCs) suppressed osteogenic differentiation. NRF2 activation increased the expression of STRO-1 and KITLG (stem cell markers), indicating NRF2 protects HBMSCs stemness against osteogenic differentiation. In contrast, NRF2 activation enhanced mineralization, which is typically linked to osteogenic differentiation. We determined that these divergent results were due in part to the modulation of cellular calcium flux genes by NRF2 activation. The current findings demonstrate a dual role for NRF2 as a HBMSC maintenance factor as well as a central factor in mineralization, with implications therein for elucidation of bone formation and cellular Ca2+ kinetics, dystrophic calcification and, potentially, application in the modulation of bone formation.

Asperuloside activates hepatic NRF2 signaling to stimulate mitochondrial metabolism and restore lipid homeostasis in high fat diet-induced MAFLD

BackgroundNutrient overload predisposes the development of metabolic dysfunction-associated fatty liver disease (MAFLD). However, there are no specific pharmacological therapies for MAFLD. Asperuloside (ASP), an iridoid glycoside extracted from Eucommia ulmoides leaves, can alleviate obesity and MAFLD. However, the underlying mechanism and pharmacological effects of ASP on ameliorating MAFLD remain largely investigated. This study aimed to explore the effects of ASP in ameliorating MAFLD and to unravel its underlying mechanism using a high fat diet-induced MAFLD mice model. MethodsSix-week-old C57BL/6 male mice were fed a high fat diet for 12 weeks to induce MAFLD, followed by daily ASP treatment (50 mg/kg via oral gavage) for 7 weeks. HepG2 cells were used for in vitro studies. Nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor, ML385, was employed to explore the mechanisms of ASP's action. ResultsASP stimulated lipolysis and inhibited de novo lipogenesis, contributing to alleviating lipid deposition in obese mice livers and HepG2 cells. ASP restored ATP production and reversed the impairments of mitochondrial energetics and biogenesis in obese mice livers and HepG2 cells. ASP attenuated oxidative stress in obese mice livers and HepG2 cells, exhibiting its antioxidant value. Impressively, ASP significantly promotes Nrf2 nuclear translocation and Nrf2/ARE binding, thereby activating Nrf2/ARE pathway in obese mice livers and HepG2 cells, demonstrating its potential as a hepatic Nrf2 activator. Nrf2 inhibition abolishes the protective effects of ASP against lipid deposition, oxidative stress and mitochondrial dysfunction, emphasizing the critical role of ASP-activated hepatic Nrf2 signaling in ameliorating MAFLD. ConclusionsThis study provides the first line of evidence demonstrating the pivotal role of ASP-stimulated Nrf2 activation in alleviating MAFLD, emphasizing its potential as a hepatic Nrf2 activator targeting fatty liver diseases. These findings offer new evidence of ASP-stimulated mitochondrial metabolism and lipolysis in MAFLD, paving the way for the development of ASP as a therapeutic agent and dietary supplement to attenuate MAFLD progression.

Microbially mediated phenolic catabolites exert differential genoprotective activities in normal and adenocarcinoma cell lines

Age-associated decline of nuclear factor erythroid 2-related factor 2 (Nrf2) activity and DNA repair efficiency leads to the accumulation of DNA damage and increased risk of cancer. Understanding the mechanisms behind increased levels of damaged DNA is crucial for developing interventions to mitigate age-related cancer risk. Associated with various health benefits, (poly)phenols and their microbially mediated phenolic catabolites represent a potential means to reduce DNA damage. Four colonic-microbiota-derived phenolic catabolites were investigated for their ability to reduce H2O2-induced oxidative DNA damage and modulate the Nrf2-Antixoidant Response Element (ARE) pathway, in normal (CCD 841 CoN) and adenocarcinoma (HT29) colonocyte cell lines. Each catabolite demonstrated significant (p < .001) genoprotective activity and modulation of key genes in the Nrf2-ARE pathway. Overall, the colon-derived phenolic metabolites, when assessed at physiologically relevant concentrations, reduced DNA damage in both normal and adenocarcinoma colonic cells in response to oxidative challenge, mediated in part via upregulation of the Nrf2-ARE pathway.

Advancing Epigenetic and Antioxidant Strategies in Natural Therapeutics Against SARS-CoV-2: A Mini Review of Current Innovations and Future Directions

Abstract: This review explores the potential of natural products, particularly curcumin and gingerol, as immune regulators and anti-inflammatory agents in combating SARS-CoV-2 infections via epigenetic and antioxidant mechanisms. Oxidative stress induced by coronavirus infections can trigger severe immune responses, such as cytokine storms, often leading to therapy failure. This oxidative stress is exacerbated by depleted antioxidant defenses. The review examines how natural ingredients activate endogenous antioxidants through pathways like nuclear factor erythroid 2-related factor 2 (Nrf-2) activation, leading to gene expression changes without altering DNA structure. These changes enhance cellular defenses against oxidative stress and reduce inflammation, potentially mitigating the virus's effects. The methodology involved a literature review of scientific articles from databases such as Google Scholar, Elsevier, Science Direct, Scopus, and Wiley Online Library, focusing on publications from 2010 to 2023. Data were analyzed using deductive qualitative descriptive techniques, emphasizing the role of natural compounds in activating antioxidant responses to prevent or minimize cellular damage caused by COVID-19. The review underscores the significant role of diet and nutritional intake in supporting the body's antioxidant capacity by activating specific receptors that influence gene expression related to immune responses and cellular repair mechanisms. Flavonoids and anthocyanins are highlighted as key compounds in natural products with therapeutic potential against COVID-19. Overall, this research advocates for further exploration of natural products as viable options for preventing and treating COVID-19, suggesting that these compounds offer dual benefits of antiviral activity and immune modulation through epigenetic regulation and antioxidant support.

Carthamus tinctorius L. (Safflower) Flower Extract Attenuates Hepatic Injury and Steatosis in a Rat Model of Type 2 Diabetes Mellitus via Nrf2-Dependent Hypoglycemic, Antioxidant, and Hypolipidemic Effects.

This study aimed to examine the hepatic and anti-steatotic protective effects of methanolic extract from Carthamus tinctorius (safflower) flowers (SFFE), using a rat model of type 2 diabetes mellitus (T2DM), and to examine the molecular mechanisms underlying these effects. Adult male Wistar rats were used for this study. First, T2DM was induced in some rats by feeding them a high-fat diet (HFD) for 4 weeks, followed by a single dose of streptozotocin (STZ) (35 mg/kg, i.p.). Experimental groups included the following five groups (n = 8 in each): control, control + SFFE, T2DM, T2DM + SFFE, and T2DM + SFFE + brusatol (an Nrf2 inhibitor, 2 mg/kg, i.p.). SFFE was administered at a concentration of 300 mg/kg, and all experiments concluded after 8 weeks. Treatments with SFFE significantly reduced fasting blood glucose levels, free fatty acids (FFAs), cholesterol, triglycerides, and low-density lipoprotein cholesterol in both the control and T2DM rats, but they failed to reduce fasting insulin levels in these groups. SFFE treatments also improved the liver structure and reduced hepatocyte vacuolization and hepatic levels of triglycerides and cholesterol in T2DM rats, in addition to increasing the hepatic mRNA levels of keap1 and the cytoplasmic levels and nuclear activities of Nrf2 in both the control and T2DM rats. SFFE also stimulated the expression levels of PPARα and CPT-1 but reduced the malondialdehyde (MDA), mRNA levels of SREBP1, fatty acid synthase, and acetyl CoA carboxylase in both the control and T2DM rats; meanwhile, it reduced hepatic mRNA and the nuclear activities of NF-κB and increased levels of glutathione, superoxide dismutase, and heme oxygenase-1 in the livers of both groups of treated rats. Furthermore, SFFE suppressed the levels of caspase-3, Bax, tumor necrosis factor-α, and interleukin-6 in the T2DM rats. Treatment with brusatol prevented all of these effects of SFFE. In conclusion, SFFE suppresses liver damage and hepatic steatosis in T2DM through Nrf2-dependent hypoglycemic, antioxidant, anti-inflammatory, and hypolipidemic effects.

Low ozone concentrations do not exert cytoprotective effects on tamoxifen-treated breast cancer cells in vitro.

Medical treatment with low ozone concentrations proved to exert therapeutic effects in various diseases by inducing a cytoprotective antioxidant response through the nuclear factor erythroid derived-like 2 (Nrf2) transcription factor pathway. Low ozone doses are increasingly administered to oncological patients as a complementary treatment to mitigate some adverse side-effects of antitumor treatments. However, a widespread concern exists about the possibility that the cytoprotective effect of Nrf2 activation may confer drug resistance to cancer cells or at least reduce the efficacy of antitumor agents. In this study, the effect of low ozone concentrations on tamoxifen-treated MCF7 human breast cancer cells has been investigated in vitro by histochemical and molecular techniques. Results demonstrated that cell viability, proliferation and migration were generally similar in tamoxifen-treated cells as in cells concomitantly treated with tamoxifen and ozone. Notably, low ozone concentrations were unable to overstimulate the antioxidant response through the Nfr2 pathway, thus excluding a possible ozone-driven cytoprotective effect that would lead to increased tumor cell survival during the antineoplastic treatment. These findings, though obtained in an in vitro model, support the hypothesis that low ozone concentrations do not interfere with the tamoxifen-induced effects on breast cancer cells.

Sulforaphane improves post-resuscitation myocardial dysfunction by inhibiting cardiomyocytes ferroptosis via the Nrf2/IRF1/GPX4 pathway

BackgroundFerroptosis is an important type of cell death contributing to myocardial dysfunction induced by whole body ischemia reperfusion following cardiac arrest (CA) and resuscitation. Sulforaphane (SFN), known as the activator of the nuclear factor E2-related factor 2 (Nrf2), has been proven to effectively alleviate regional myocardial ischemia reperfusion injury. The present study was designed to investigate whether SFN could improve post-resuscitation myocardial dysfunction by inhibiting cardiomyocytes ferroptosis and its potential regulatory mechanism. Methods and resultsAn in vivo pig model of CA and resuscitation was established. Hypoxia/reoxygenation (H/R)-stimulated AC16 cardiomyocytes was constructed as an in vitro model to simulate the process of CA and resuscitation. In vitro experiment, SFN reduced ferroptosis-related ferrous iron, lipid reactive oxygen species, and malondialdehyde, increased glutathione, and further promoted cell survival after H/R stimulation in AC16 cardiomyocytes. Mechanistically, the activation of Nrf2 with the SFN decreased interferon regulatory factor 1 (IRF1) expression, then reduced its binding to the promoter of glutathione peroxidase 4 (GPX4), and finally recovered the latter’s transcription after H/R stimulation in AC16 cardiomyocytes. In vivo experiment, SFN reversed abnormal expression of IRF1 and GPX4, inhibited cardiac ferroptosis, and improved myocardial dysfunction after CA and resuscitation in pigs. ConclusionsSFN could effectively improve myocardial dysfunction after CA and resuscitation, in which the mechanism was potentially related to the inhibition of cardiomyocytes ferroptosis through the regulation of Nrf2/IRF1/GPX4 pathway.

Asperuloside as a Novel NRF2 Activator to Ameliorate Endothelial Dysfunction in High Fat Diet-Induced Obese Mice.

Aims: Current treatments are inadequate in alleviating obesity-associated vascular diseases. The development of effective therapies to ameliorate endothelial dysfunction and attenuate oxidative stress is of utmost importance. Asperuloside (ASP), a bioactive compound extracted from Eucommia species, exhibits antiobesity properties. However, the effects of ASP on vasculopathy have not been investigated. Therefore, the effects of ASP on vascular dysfunction and related mechanisms were elucidated. Results: ASP significantly reversed the impaired endothelium-dependent relaxations (EDRs) in obese mice and interleukin (IL)-1β-treated aortas. ASP suppressed endothelial activation in obese mice aortas and IL-1β-treated endothelial cells. ASP attenuated oxidative stress, scavenged mitochondrial reactive oxygen species (ROS), and upregulated heme oxygenase-1 (HO-1) expression in endothelium, independent of its anti-inflammatory properties. HO-1 knockdown diminished the protective effects of ASP against impaired EDRs, ROS overproduction, and endothelial activation. Endothelial cell-specific nuclear factor erythroid 2-related factor 2 (Nrf2) knockdown eliminated the ASP-mediated vascular protective effects and endothelial HO-1 upregulation, emphasizing that ASP improves endothelial function by activating Nrf2/HO-1 signaling. ASP facilitated Nrf2 nuclear translocation and the direct binding of Nrf2 to antioxidant response element, thereby enhancing HO-1 transcription and scavenging ROS. The cellular thermal shift assay results provide the first experimental characterization of the direct binding of ASP to Nrf2. Conclusions: These findings demonstrate that ASP ameliorates obesity-associated endothelial dysfunction by activating Nrf2/HO-1 signaling and thereby maintaining redox hemostasis, suggesting its potential as a novel Nrf2-targeted therapeutic agent and dietary supplement for vasculopathy.