Nrf2 Activation Research Articles

Effects of Yishentongluo Recipe on Nrf2 and HO-1 pathway activation leading to reduction of oxidative stress and kidney fibrosis in membranous nephropathy rat model

This study investigated Yishentongluo Recipe (YSTLF) effects on renal oxidative stress and fibrosis in membranous nephropathy (MN) rats. MN was induced by cationized bovine serum albumin injection. Rats were divided intocontrol, MN, YSTLF, and benazepril groups. After four weeks of treatment, urine protein levels (UTP), serum total cholesterol (TC), triglycerides (TG), total protein (TP), and albumin (ALB) were assessed. Kidney microstructure, IgG immune complex deposition, and protein expressions of superoxide dismutase (SOD), malondialdehyde (MDA), transforming growth factor β1 (TGF-β1), collagen I (Collagen-I), α-smooth muscle actin (α-SMA), nuclear factor E2-related factor (Nrf2), haem oxygenase 1 (HO-1), and NADPH oxidase 4 (NOX4) were evaluated. YSTLF and BNPL treatments reduced UTP, TC, TG, increased TP and ALB levels, downregulated TGF-β1, Collagen-I, and α-SMA, and upregulated Nrf2, HO-1, and NOX4. YSTLF partially reversed SOD reduction and MDA elevation, suggesting its efficacy in alleviating renal oxidative stress and fibrosis in MN rats via Nrf2/HO-1 signaling pathway activation.

Ameliorative Effect of Hedysarum polybotrys Polysaccharide on Neural Tissue Fibrosis in Diabetic Peripheral Neuropathy Mice and its Mechanisms

Objective: This study aimed to investigate the role of Hedysarum polybotrys polysaccharide (HPS) in ameliorating neural tissue fibrosis in diabetic peripheral neuropathy (DPN) mice. Methods: Fifty DPN mice were selected and randomly divided into five groups (n = 10), which were the model group, positive control group (receiving only 4 mg/(kg-d) of α-lipoic acid), high-dose HPS group (200 mg/(kg-d) of HPS was given per day), medium-dose HPS group (100 mg/(kg-d) of HPS was given per day), and low-dose HPS group (50 mg/(kg-d) of HPS given daily). In addition, non-diabetic C57BL/6 wild-type mice were selected as the normal group (n = 10). The expression levels of Keap1 and Nrf2 proteins and their mRNAs in the sciatic nerve tissues of mice in each group were analyzed by Western blot technique and real-time fluorescence quantitative PCR. Results: Compared with the normal group, the expression of Keap1 protein and mRNA was increased, while the expression of Nrf2 protein and mRNA was decreased in the sciatic nerve of mice in the model group (P < 0.05). Compared with the model group, Keap1 protein and mRNA expression decreased, while Nrf2 protein and mRNA expression increased in the control and high and medium dose HPS groups of mice (P < 0.05). Conclusion: HPS may inhibit fibrosis of neural tissue and ameliorate nerve injury in DPN mice by regulating the Keap1/Nrf2 signaling pathway. This effect was associated with enhanced antioxidant capacity, promotion of Nrf2 activation, and increased antioxidant gene expression by HPS. Therefore, HPS has a potential therapeutic value to ameliorate DPN-associated nerve injury.

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.

Cynarin inhibits microglia-induced pyroptosis and neuroinflammation via Nrf2/ROS/NLRP3 axis after spinal cord injury.

Spinal cord injury (SCI) elicits excess neuroinflammation and resident microglial pyroptosis, leading further terrible neurological collapse and locomotor dysfunction. However, the current clinical therapy is useless and a feasible treatment is urgent to be explored. Cynarin is a natural component in artichoke playing anti-inflammatory and anti-aging roles in hepatoprotection and cardioprotection, but it is unclear that the pharmacologic action and underlying mechanism of Cynarin in neuropathy. Using the SCI mouse model and the BV2 cell line, we here investigated whether Cynarin reduces neuroinflammation and pyroptosis to promote neurological recovery after SCI. Our results showed that treatment with Cynarin reduces the level of neuroinflammation and microglial pyroptosis. Moreover, the mice treated with Cynarin exhibited lower level of reactive oxygen species (ROS) and cell death, less damage of neurohistology and better locomotor improvement of hindlimbs than the untreated mice and the nuclear factor erythroid 2-related factor 2 (Nrf2)-inhibited mice. Mechanically, Cynarin inhibited the assembly of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome by Nrf2-dependent expression to attenuate microglial pyroptosis and neuroinflammation. To sum up, the current study suggested that administration of Cynarin is a promising compound for anti-neuroinflammation and anti-pyroptosis after SCI. It may be an efficient Nrf2 activator and a NLRP3 inhibitor for microglia in neuropathies.

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.