CRHR1 antagonist alleviated depression-like behavior by downregulating p62 in a rat model of post-stroke depression.

Post-stroke depression (PSD) is a complication of cerebrovascular disease, which can increase mortality after stroke. CRH is one of the main signaling peptides released after activation of the hypothalamic-pituitary-adrenal (HPA) axis in response to stress. It affects synaptic plasticity by regulating inflammation, oxidative stress and autophagy in the central nervous system. And the loss of spines exacerbates depression-like behavior. Therefore, synaptic deficits induced by CRH may be related to post-stroke depression. However, the underlying mechanism remains unclear. The Keap1-Nrf2 complex is one of the core components of the antioxidant response. As an autophagy associated protein, p62 participates in the Keap1-NrF2 pathway through its Keap1 interaction domain. Oxidative stress is involved in the feedback regulation between Keap1-Nrf2 pathway and p62.However, whether the relationship between CRH and the Keap1-Nrf2-p62 pathway is involved in PSD remains unknown. This study found that serum levels of CRH in 22 patients with PSD were higher than those in healthy subjects. We used MCAO combined with CUMS single-cage SD rats to establish an animal model of PSD. Animal experiments showed that CRHR1 antagonist prevented synaptic loss in the hippocampus of PSD rats and alleviated depression-like behavior. CRH induced p62 accumulation in the prefrontal cortex of PSD rats through CRHR1. CRHR1 antagonist inhibited Keap1-Nrf2-p62 pathway by attenuating oxidative stress. In addition, we found that abnormal accumulation of p62 induces PSD. It alleviates depression-like behavior by inhibiting the expression of p62 and promoting the clearance of p62 in PSD rats. These findings can help explore the pathogenesis of PSD and design targeted treatments for PSD.

Activation of the Keap1/Nrf2 pathway suppresses mitochondrial dysfunction, oxidative stress, and motor phenotypes in C9orf72 ALS/FTD models.

Mitochondrial dysfunction is a common feature of C9orf72 amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD); however, it remains unclear whether this is a cause or consequence of the pathogenic process. Analysing multiple aspects of mitochondrial biology across several Drosophila models of C9orf72-ALS/FTD, we found morphology, oxidative stress, and mitophagy are commonly affected, which correlated with progressive loss of locomotor performance. Notably, only genetic manipulations that reversed the oxidative stress levels were also able to rescue C9orf72 locomotor deficits, supporting a causative link between mitochondrial dysfunction, oxidative stress, and behavioural phenotypes. Targeting the key antioxidant Keap1/Nrf2 pathway, we found that genetic reduction of Keap1 or pharmacological inhibition by dimethyl fumarate significantly rescued the C9orf72-related oxidative stress and motor deficits. Finally, mitochondrial ROS levels were also elevated in C9orf72 patient-derived iNeurons and were effectively suppressed by dimethyl fumarate treatment. These results indicate that mitochondrial oxidative stress is an important mechanistic contributor to C9orf72 pathogenesis, affecting multiple aspects of mitochondrial function and turnover. Targeting the Keap1/Nrf2 signalling pathway to combat oxidative stress represents a therapeutic strategy for C9orf72-related ALS/FTD.

Chemopreventive effects of atractylenolide-III on mammary tumorigenesis via activation of the Nrf2/ARE pathway through autophagic degradation of Keap1.

The incidence of breast cancer is increasing annually, making it a major health threat for women. Chemoprevention using natural, dietary, or synthetic products has emerged as a promising approach to address this growing burden. Atractylenolide-III (AT-III), a sesquiterpenoid present in various medicinal herbs, has demonstrated potential therapeutic effects against several diseases, including tumors, nonalcoholic fatty liver disease, and cerebral ischemic injury. However, its impact on breast cancer chemoprevention remains unexplored. In this study, we used an N-methyl-N-nitrosourea (NMU)-induced rat breast cancer model and 17ß-estradiol (E2)-treated MCF-10A cells to evaluate the chemopreventive potential of AT-III on mammary tumorigenesis. AT-III inhibited mammary tumor progression, evidenced by reduced tumor volume and multiplicity, prolonged tumor latency, and the reversal of NMU-induced weight loss. Furthermore, AT-III suppressed NMU-induced inflammation and oxidative stress through the Nrf2/ARE pathway in breast cancer tissues. In vitro, AT-III effectively suppressed E2-induced anchorage-independent growth and cell migration in MCF-10A cells. Nrf2 knockdown attenuated the protective effects of AT-III, highlighting the pivotal role of Nrf2 in AT-III-mediated suppression of tumorigenesis. The mechanism involves the induction of Nrf2 expression by AT-III through the autophagic degradation of Kelch-like ECH-associated protein 1 (Keap1). Overall, the results of this study indicate that AT-III is a promising candidate for breast cancer chemoprevention and provide valuable insights into its molecular interactions and signaling pathways.

CPEB1 Controls NRF2 Proteostasis and Ferroptosis Susceptibility in Pancreatic Cancer.

Pancreatic cancer is the deadliest malignancy with a poor response to chemotherapy but is potentially indicated for ferroptosis therapy. Here we identified that cytoplasmic polyadenylation element binding protein 1 (CPEB1) regulates NRF2 proteostasis and susceptibility to ferroptosis in pancreatic ductal adenocarcinoma (PDAC). We found that CPEB1 deficiency in cancer cells promotes the translation of p62/SQSTM1 by facilitating mRNA polyadenylation. Consequently, upregulated p62 enhances NRF2 stability by sequestering KEAP1, an E3 ligase for proteasomal degradation of NRF2, leading to the transcriptional activation of anti-ferroptosis genes. In support of the critical role of this signaling cascade in cancer therapy, CPEB1-deficient pancreatic cancer cells display higher resistance to ferroptosis-inducing agents than their CPEB1-normal counterparts in vitro and in vivo. Furthermore, based on the pathological evaluation of tissue specimens from 90 PDAC patients, we established that CPEB1 is an independent prognosticator whose expression level is closely associated with clinical therapeutic outcomes in PDAC. These findings identify the role of CPEB1 as a key ferroptosis regulator and a potential prognosticator in pancreatic cancer.

A double whammy for KEAP1.

In this issue of Cell Chemical Biology, Lu et al.1 report the discovery of a bivalent KEAP1 inhibitor (biKEAP1), which more rapidly activates NRF2 compared to previously reported monovalent KEAP1 inhibitors. biKEAP1suppresses acute inflammation in animal models.

PPIA dictates NRF2 stability to promote lung cancer progression.

Nuclear factor erythroid 2-related factor 2 (NRF2) hyperactivation has been established as an oncogenic driver in a variety of human cancers, including non-small cell lung cancer (NSCLC). However, despite massive efforts, no specific therapy is currently available to target NRF2 hyperactivation. Here, we identify peptidylprolyl isomerase A (PPIA) is required for NRF2 protein stability. Ablation of PPIA promotes NRF2 protein degradation and blocks NRF2-driven growth in NSCLC cells. Mechanistically, PPIA physically binds to NRF2 and blocks the access of ubiquitin/Kelch Like ECH Associated Protein 1 (KEAP1) to NRF2, thus preventing ubiquitin-mediated degradation. Our X-ray co-crystal structure reveals that PPIA directly interacts with a NRF2 interdomain linker via a trans-proline 174-harboring hydrophobic sequence. We further demonstrate that an FDA-approved drug, cyclosporin A (CsA), impairs the interaction of NRF2 with PPIA, inducing NRF2 ubiquitination and degradation. Interestingly, CsA interrupts glutamine metabolism mediated by the NRF2/KLF5/SLC1A5 pathway, consequently suppressing the growth of NRF2-hyperactivated NSCLC cells. CsA and a glutaminase inhibitor combination therapy significantly retard tumor progression in NSCLC patient-derived xenograft (PDX) models with NRF2 hyperactivation. Our study demonstrates that targeting NRF2 protein stability is an actionable therapeutic approach to treat NRF2-hyperactivated NSCLC.

Spilanthes filicaulis (Schumach. & Thonn.) C. D Adam leaf extract prevents assault of streptozotocin on liver cells via inhibition of oxidative stress and activation of the NrF2/Keap1, PPARγ, and PTP1B signaling pathways.

BACKGROUND: Spilanthes filicaulis (Schumach. & Thonn.) C. D Adam is a shrubby plant of the Asteraceae family that has medicinal benefits for the pharmaceutical and cosmetic industries. PURPOSE: The purpose of this study was to assess the effectiveness of Spilanthes filicaulis leaf extract in a streptozotocin (STZ)-induced rat model and the associated signaling pathways. METHODS: A sample of 25 male Wistar rats was randomly assigned to groups I, II, III, IV, and V. Each group included five animals, i.e., control rats, diabetic control rats, diabetic rats treated with metformin, and diabetic rats treated with 150 mg/kg/bw and 300 mg/kg/bw of the methanolic extract of S. filicaulis leaves (MESFL). Treatment was administered for 15 successive days via oral gavage. After 15 days, the rats were evaluated for fasting blood glucose (FBG), glycated hemoglobin (HbA1c), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), reduced glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), lipid peroxidation (MDA), hexokinase, and glucose-6-phosphatase activities. Gene expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), peroxisome proliferator-activated receptor gamma (PPAR-γ), kelch-like ECH-associated protein 1 (Keap1), protein tyrosine phosphatase 1B (PTP1B) and the antiapoptotic protein caspase-3 were examined. RESULTS: MESFL was administered to diabetic rats, and changes in body weight, fasting blood glucose (FBG) and HbA1c were restored. Furthermore, in diabetic rats, S. filicaulis significantly reduced the levels of triglycerides (TGs), total cholesterol (TC), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) and significantly increased HDL. S. filicaulis improved ALT, AST, and ALP enzyme activity in diabetic rats. MDA levels decreased considerably with increasing activity of antioxidant enzymes, such as GST, SOD, CAT and GSH, in diabetic liver rats treated with S. filicaulis. Diabetic rats treated with MESFL and metformin exhibited upregulated mRNA expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and peroxisome proliferator-activated receptor gamma (PPAR-γ). Kelch-like ECH-associated protein 1 (Keap1) and protein tyrosine phosphatase 1B (PTP1B) mRNA expression in the liver was downregulated in diabetic rats treated with MESFL and metformin. In addition, MESFL downregulated the mRNA expression of caspase-3 in diabetic rats. CONCLUSION: It can be concluded from the data presented in this study that MESFL exerts a protective effect on diabetic rats due to its antidiabetic, antioxidant, antihyperlipidemic and antiapoptotic effects and may be considered a treatment for T2DM.

Fucoxanthin Induces Ferroptosis in Cancer Cells via Downregulation of the Nrf2/HO-1/GPX4 Pathway.

This study investigated the mechanism by which fucoxanthin acts as a novel ferroptosis inducer to inhibit tongue cancer. The MTT assay was used to detect the inhibitory effects of fucoxanthin on SCC-25 human tongue squamous carcinoma cells. The levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and total iron were measured. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting were used to assess glutathione peroxidase 4 (GPX4), nuclear factor erythroid 2-related factor 2 (Nrf2), Keap1, solute carrier family 7 member 11 (SLC7A11), transferrin receptor protein 1 (TFR1), p53, and heme oxygenase 1 (HO-1) expression. Molecular docking was performed to validate interactions. Compared with the control group, the activity of fucoxanthin-treated SCC-25 cells significantly decreased in a dose- and time-dependent manner. The levels of MMP, GSH, and SOD significantly decreased in fucoxanthin-treated SCC-25 cells; the levels of ROS, MDA, and total iron significantly increased. mRNA and protein expression levels of Keap1, GPX4, Nrf2, and HO-1 in fucoxanthin-treated cells were significantly decreased, whereas levels of TFR1 and p53 were significantly increased, in a concentration-dependent manner. Molecular docking analysis revealed that binding free energies of fucoxanthin with p53, SLC7A11, GPX4, Nrf2, Keap1, HO-1, and TFR1 were below -5 kcal/mol, primarily based on active site hydrogen bonding. Our findings suggest that fucoxanthin can induce ferroptosis in SCC-25 cells, highlighting its potential as a treatment for tongue cancer.

Ginsenoside Rg3 attenuates myocardial ischemia/reperfusion-induced ferroptosis via the keap1/Nrf2/GPX4 signaling pathway.

BACKGROUND: Ginsenoside Rg3 is a component of ginseng that protects against myocardial ischemia/reperfusion (MI/R) injury. Ferroptosis is a new form of cell death characterized by oxidative damage to phospholipids. The purpose of this study was to examine the role and of ginsenoside Rg3 in MI/R and the mechanism. METHODS: A mouse model of left anterior descending (LAD) ligation-induced myocardial ischemia/reperfusion (MI/R) injury and oxygen-glucose deprivation/reperfusion (OGD/R) were used as in vitro and in vivo models, respectively. Echocardiographic analysis, 2,3,5-triphenyltetrazolium chloride (TTC) staining and hematoxylin-eosin (H&E) staining were used to assess the cardioprotective effects of ginsenoside Rg3. Western blotting, biochemical analysis, small interfering RNA analysis and molecular docking were performed to examine the underlying mechanism. RESULTS: Ginsenoside Rg3 improved cardiac function and infarct size in mice with MI/R injury. Moreover, ginsenoside Rg3 increased the expression of the ferroptosis-related protein GPX4 and inhibited iron deposition in mice with MI/R injury. Ginsenoside Rg3 also activated the Nrf2 signaling pathway. Ginsenoside Rg3 attenuated myocardial ischemia/reperfusion-induced ferroptosis via the Nrf2 signaling pathway. Notably, ginsenoside Rg3 regulated the keap1/Nrf2 signaling pathway to attenuate OGD/R-induced ferroptosis in H9C2 cells. Taken together, ginsenoside Rg3 attenuated myocardial ischemia/reperfusion-induced ferroptosis via the keap1/Nrf2/GPX4 signaling pathway. CONCLUSIONS: Our findings demonstrated that ginsenoside Rg3 ameliorate MI/R-induced ferroptosis via the keap1/Nrf2/GPX4 signaling pathway.

Therapeutic potential of salvigenin to combat atrazine induced liver toxicity in rats via regulating Nrf-2/Keap-1 and NF-κB pathway.

Atrazine (ATR) is the second most extensively used herbicide which adversely affects the body organs including liver. Salvigenin (SGN) is a flavonoid which demonstrates a wide range of biological and pharmacological abilities. This study was planned to assess the protective ability of SGN to avert ATR induced liver damage in rats. Thirty-two rats (Rattus norvegicus) were divided into four groups including control, ATR (5 mg/kg), ATR (5 mg/kg) + SGN (10 mg/kg) and SGN (10 mg/kg) alone supplemented group. ATR exposure reduced the expression of Nrf-2 while instigating an upregulation in Keap-1 expression. Furthermore, the activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), heme­oxygenase-1 (HO-1) and glutathione reductase (GSR) contents were decreased while increasing reactive oxygen species (ROS) and malondialdehyde (MDA) levels after ATR treatment. Moreover, ATR poisoning increased the levels of ALT, AST, and ALP while reducing the levels of total proteins, and albumin in hepatic tissues of rats. Besides, ATR administration escalated the expressions of Bax and Caspase-3 while inducing a downregulation in the expressions of Bcl-2. Similarly, ATR intoxication increased the levels of Interleukin-6 (IL-6), Nuclear factor kappa-B (NF-κB), Interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and the activity of cyclooxygenase-2 (COX-2). Furthermore, ATR disrupted the normal histology of hepatic tissues. However, SGN treatment remarkably protected the liver tissues via regulating antioxidant, anti, inflammatory, anti-apoptotic as well as histology parameters. Therefore, it is concluded that SGN can be used as therapeutic agent to combat ATR-induced hepatotoxicity.

Echinatin attenuates acute lung injury and inflammatory responses via TAK1-MAPK/NF-κB and Keap1-Nrf2-HO-1 signaling pathways in macrophages.

Echinatin is an active ingredient in licorice, a traditional Chinese medicine used in the treatment of inflammatory disorders. However, the protective effect and underlying mechanism of echinatin against acute lung injury (ALI) is still unclear. Herein, we aimed to explore echinatin-mediated anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated ALI and its molecular mechanisms in macrophages. In vitro, echinatin markedly decreased the levels of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated murine MH-S alveolar macrophages and RAW264.7 macrophages by suppressing inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) expression. Furthermore, echinatin reduced LPS-induced mRNA expression and release of interleukin-1ß (IL-1ß) and IL-6 in RAW264.7 cells. Western blotting and CETSA showed that echinatin repressed LPS-induced activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) pathways through targeting transforming growth factor-beta-activated kinase 1 (TAK1). Furthermore, echinatin directly interacted with Kelch-like ECH-associated protein 1 (Keap1) and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway to enhance heme oxygenase-1 (HO-1) expression. In vivo, echinatin ameliorated LPS-induced lung inflammatory injury, and reduced production of IL-1ß and IL-6. These findings demonstrated that echinatin exerted anti-inflammatory effects in vitro and in vivo, via blocking the TAK1-MAPK/NF-κB pathway and activating the Keap1-Nrf2-HO-1 pathway.

Diesel exhaust particulate matter induces GC-1 spg cells oxidative stress by KEAP1-NRF2 pathway and inhibition of ATP5α1 S-sulfhydration.

Diesel exhaust particle (DEP) exposure induces a variety of toxicological effects through oxidative stress and inflammation responses. This research investigated the mechanisms underlying DEP-induced GC-1spg cells oxidative stress by examining ROS accumulation, antioxidant defense systems activation, mitochondrial dysfunction, and the Nrf2/Keap1/HO-1 pathway response. Subsequently, we further evaluated the ATP levels, ATP5α synthase activity and ATP5α synthase S-sulfhydrated modification in DEP-exposed GC-1 spg cells. The results showed that DEP exposure significantly inhibited cell proliferation and viability, increased intracellular ROS production, decreased MMP, down-regulated antioxidant capacity, activated the Nrf2/Keap1/HO-1 pathway. However, DEP-induced oxidative stress was partially alleviated by GSH and exogenous H2S. In addition, DEP exposure induced ATP depletion and ATP5α synthase inactivity in GC-1 spg cells, accompanied by ATP5α synthase S-sulfhydrated modification. In conclusion, our research showed that DEP may incapacitate mitochondria through oxidative stress injury, leading to GC-1 spg cells oxidative stress. This process may be associated with the reduction of ATP5α1 S-sulfhydrated modification. It provides a new perspective for the research of the mechanism related to male reproductive toxicity due to air pollution.

Gypenoside XLIX alleviates intestinal injury by inhibiting sepsis-induced inflammation, oxidative stress, apoptosis, and autophagy.

Intestinal barrier dysfunction is a significant complication induced by sepsis, yet therapeutic strategies targeting such dysfunction remain inadequate. This study investigates the protective effects of Gypenoside XLIX (Gyp XLIX) against intestinal damage induced by sepsis. Septic intestinal injury in mice was induced by cecum ligation and puncture (CLP) surgery. The biological activity and potential mechanisms of Gyp XLIX were explored through intraperitoneal injection of Gyp XLIX (40 mg/kg). The study demonstrates that Gyp XLIX improves the pathological structural damage of the intestine and increases tight junction protein expression as well as the number of cup cells. Through activation of the nuclear factor erythroid 2-related factor 2 - Kelch-like ECH-associated protein 1 (Nrf2-Keap1) pathway, Gyp XLIX enhances antioxidant enzyme levels while reducing the excessive accumulation of reactive oxygen species (ROS). In addition, Gyp XLIX effectively alleviates sepsis-induced intestinal inflammation by inhibiting the nuclear factor kappa B (NF-κB) pathway and activation of the NLRP3 inflammasome. Moreover, Gyp XLIX inhibits cell death through modifying phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, further enhancing its ability to shield the intestinal barrier. The combined action of these molecular mechanisms promotes the restoration of immune balance and reduces excessive autophagy activity induced under septic conditions. In summary, Gyp XLIX exhibits a significant preventive action against intestinal damage brought on by sepsis, with its mechanisms involving the improvement of intestinal barrier function, antioxidative stress, inhibition of inflammatory response, and cell apoptosis. This research offers a potential strategy for addressing intestinal barrier impairment brought on by sepsis.

[Mechanism of tetramethylpyrazine combined with neural stem cells transplantation on cerebral ischemia-reperfusion rats].

This study aimed to investigate the intervention effect of tetramethylpyrazine(TMP) combined with transplantation of neural stem cells(NSCs) on middle cerebral artery occlusion(MCAO) rat model and to explore the mechanism of TMP combined with NSCs transplantation on ischemic stroke based on the regulation of stem cell biological behavior. MCAO rats were randomly divided into a model group, a TMP group, an NSCs transplantation group, and a TMP combined with NSCs transplantation group according to neurological function scores. A sham group was set up at the same time. The neurological function score was used to evaluate the improvement of neurological function in MCAO rats after TMP combined with NSCs transplantation. The proliferation, migration, and differentiation of NSCs were evaluated by BrdU, BrdU/DCX, BrdU/NeuN, and BrdU/GFAP immunofluorescence labeling. The protein expression of stromal cell-derived factor 1(SDF-1), C-X-C motif chemokine receptor 4(CXCR4), as well as oxidative stress pathway proteins nuclear factor erythroid 2-related factor 2(Nrf2), Kelch-like ECH-associated protein 1(KEAP1), heme oxygenase 1(HO-1), NAD(P)H quinone oxidoreductase 1(NQO1) was detected by Western blot to study the migration mechanism of TMP combined with NSCs. The results showed that TMP combined with NSCs transplantation significantly improved the neurological function score in MCAO rats. Immunofluorescence staining showed a significant increase in the number of BrdU~+, BrdU~+/DCX~+, BrdU~+/NeuN~+, and BrdU~+/GFAP~+ cells in the TMP, NSCs transplantation, and combined treatment groups, with the combined treatment group showing the most significant increase. Further Western blot analysis revealed significantly elevated expression of CXCR4 protein in the TMP, NSCs transplantation, and combined treatment groups, along with up-regulated protein expression of Nrf2, HO-1, and NQO1, and decreased KEAP1 protein expression. This study showed that both TMP and NSCs transplantation can promote the recovery of neurological function by promoting the proliferation, migration, and differentiation of NSCs, and the effect of TMP combined with NSCs transplantation is superior. The mechanism of action may be related to the activation of the Nrf2/HO-1/CXCR4 pathway.

[Stellera chamaejasme against multidrug resistance of triple-negative breast cancer MDA-MB-231 cell through Nrf2].

This study aims to investigate the effect and mechanism of Stellera chamaejasme extract(SCL) on multidrug resistance(MDR) in breast cancer. Human triple-negative breast cancer cell line MDA-MB-231 and its adriamycin-resistant cell line MDA-MB-231/ADR were used in the experiment. Cell viability was detected by methyl thiazolyl tetrazolium(MTT) assay, and cell apoptosis was detected by DAPI staining and Annexin-V/Pi double staining. Western blot(WB) was used to detect the expression levels of Keap1, Nrf2, HO-1, Bcl-2, Bax, caspase-9, and caspase-3. Immunofluorescence staining was used to observe the distribution of Nrf2 in the cell, and flow cytometry was used to detect the level of reactive oxygen species(ROS) in the cell. The results showed that the resis-tance factor of SCL was 0.69, and that of adriamycin and paclitaxel was 8.40 and 16.36, respectively. DAPI staining showed that SCL could cause nuclear shrinkage and fragmentation of breast cancer cells. Annexin-V/Pi double staining showed that the average apoptosis rate of the drug-resistant cells was 32.64% and 50.29%, respectively under medium and high doses of SCL. WB results showed that SCL could significantly reduce the expression levels of anti-apoptotic proteins Bcl-2, caspase-9, and caspase-3 and significantly increase the expression level of pro-apoptotic protein Bax. Further studies showed that SCL could significantly promote the expression of Keap1, significantly inhibit the expression of Nrf2 and HO-1, and significantly reduce the expression level of Nrf2 in the nucleus. Correspondingly, flow cytometry showed that the intracellular ROS level was significantly increased. In conclusion, SCL can significantly inhibit the proliferation of MDA-MB-231 multidrug-resistant cells of triple-negative breast cancer and cause cell apoptosis, and the mechanism is related to inhibiting Keap1/Nrf2 signaling pathway, leading to ROS accumulation in drug-resistant cells and increasing the expression of apoptosis-related proteins.

Resveratrol targeting NRF2 disrupts the binding between KEAP1 and NRF2-DLG motif to ameliorate oxidative stress damage in mice pulmonary infection.

ETHNOPHARMACOLOGICAL RELEVANCE: The root of Polygonum cuspidatum Sieb. et Zucc (PC), known as 'Huzhang' in the Chinese Pharmacopoeia, has been traditionally employed for its anti-inflammatory, antiviral, antimicrobial, and other biological activities. Polydatin (PD) and its aglycone, resveratrol (RES), are key pharmacologically active components responsible for exerting anti-inflammatory and antioxidant effects. However, its specific targets and action mechanisms remain unclear. AIM OF THE STUDY: The equilibrium of the KEAP1-NRF2 system serves as the primary protective response to oxidative and electrophilic stresses within the body, particularly in cases of acute lung injury caused by pathogenic microbial infection. In this study, the precise mechanisms by which RES alleviates oxidative stress damage in conjunction with NRF2 activators are discussed. MATERIALS AND METHODS: The active components from PC were screened to evaluate their potential to inhibit reactive oxygen species (ROS) and activate antioxidant activity dependent on antioxidant response elements (ARE). RES was evaluated for its potential to alleviate the oxidative stress caused by pathogenic microbial infection. Functional probes were designed to study the RES distribution and identify its targets. A lipopolysaccharide (LPS)-induced oxidative injury model was used to evaluate the effects of RES on the KEAP1-NRF2/ARE pathway in RAW 264.7 cells. The interaction between RES and NRF2 was elucidated using drug-affinity responsive target stability (DARTS), cellular thermal shift assays (CETSA), co-immunoprecipitation (Co-IP), and microscale thermophoresis (MST) techniques. The key binding sites were predicted using molecular docking and validated in NRF2-knockdownand reconstructed cells. Finally, protective effects against pulmonary stress were verified in a mouse model of pathogenic infection. RESULTS: The accumulation of RES in lung macrophages disrupted the binding between KEAP1 and NRF2, thereby preventing the ubiquitination degradation of NRF2 through its interaction with Ile28 on the NRF2-DLG motif. The activation of NRF2 resulted in the upregulation of nuclear transcription, enhances the expression of antioxidant genes dependent on ARE, suppresses ROS generation, and ameliorates oxidative damage both in vivo and in vitro. CONCLUSION: These findings shed light on the potential of RES to mitigate oxidative stress damage caused by pathogenic microorganism-induced lung infections and facilitate the discovery of novel small molecule modulators targeting the KEAP1-NRF2 DLG motif interaction.

Targeting the smooth muscle cell KEAP1-Nrf2-STING axis with pterostilbene attenuates abdominal aortic aneurysm.

BACKGROUND: Abdominal aortic aneurysm (AAA) is a life-threatening aortic disease, and to date, there are currently no effective pharmacological treatments to address this condition. Activation of cytosolic DNA sensing adaptor stimulator of interferon genes (STING) signaling is a crucial mechanism in AAA formation. PURPOSE: This study investigated pterostilbene (Pt), a naturally occurring polyphenol and resveratrol analogue, as a STING inhibitor for preventing AAA. METHODS: We evaluated the effect of Pt on AAA formation in angiotensin II (AngII)-infused apolipoprotein E-deficient (ApoE-/-) mice. We used histological analysis, MMP activity measurement, western blot, and immunohistochemistry to detect AAA formation and development. We applied RNA sequencing, molecular docking, cellular thermal shift assay (CETSA) and functional studies to dissect the molecular mechanism of Pt-regulating KEAP1-Nrf2-STING signaling. We conditionally knocked down Nrf2 in vascular smooth muscle cells (VSMCs) in vivo to investigate its role in Pt-mediated protective effects on AAA. RESULTS: Pt effectively blocked the formation of AAA in AngII-infused ApoE-/- mice. Whole transcriptome sequencing analysis revealed that nuclear factor erythroid 2-related factor 2 (Nrf2) and STING pathway in VSMCs were linked to the anti-AAA effects of pterostilbene. Mechanistically, Pt upregulated Nrf2 target genes (e.g., HO-1 and NQO1) through activation of the KEAP1/Nrf2 signaling, which restricted the immunostimulatory axis of mtDNA-STING-TBK1-NF-κB, thereby alleviating VSMC inflammation and preserving the VSMC contractile phenotype. Subsequently, molecular docking and CETSA revealed a binding mode between Pt and KEAP1/Nrf2. Intriguingly, the inhibitory effect of Pt on STING signaling and the protective role of Pt in AAA were largely abrogated by VSMC-specific Nrf2 knockdown in mice. CONCLUSION: Collectively, naturally derived Pt shows promising efficacy for the treatment of AAA by targeting the KEAP1-Nrf2-STING axis in VSMCs.

Chlorpyrifos-induced suppression of the antioxidative defense system leads to cytotoxicity and genotoxicity in macrophages.

Chlorpyrifos, widely used for pest control, is known to have various harmful effects, although its toxic effects in macrophages and the mechanisms underlying its toxicity remain unclear. The present study investigated the toxic effects of chlorypyrifos in a macrophage cell line. Here, we found that chlorpyrifos induced cytotoxicity and genotoxicity in RAW264.7 macrophages. Moreover, chlorpyrifos induced intracellular ROS production, subsequently leading to lipid peroxidation. Chlorpyrifos reduced the activation of antioxidative enzymes including superoxide dismutase, catalase, and glutathione peroxidase. Chlorpyrifos upregulated HO-1 expression and activated the Keap1-Nrf2 pathway, as indicated by enhanced Nrf2 phosphorylation and Keap1 degradation. Chlorpyrifos exerted effects on the following in a dose-dependent manner: cytotoxicity, genotoxicity, lipid peroxidation, intracellular ROS production, antioxidative enzyme activity reduction, HO-1 expression, Nrf2 phosphorylation, and Keap1 degradation. Notably, N-acetyl-L-cysteine successfully inhibited chlorpyrifos-induced intracellular ROS generation, cytotoxicity, and genotoxicity. Thus, chlorpyrifos may induce cytotoxicity and genotoxicity by promoting intracellular ROS production and suppressing the antioxidative defense system activation in macrophages.

[Antioxidative effect of wheat-grain moxibustion on cyclophosphamide-induced liver injury in mice based on Nrf2-Keap1 signaling pathway].

OBJECTIVE: To observe the protective effect of wheat-grain moxibustion on cyclophosphamide (CTX)-induced liver injury in mice, and explore its mechanism based on the nuclear factor E2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) signaling pathway. METHODS: Twenty-four male CD-1 (ICR) mice were randomly divided into a blank group, a model group, and a moxibustion group, with 8 mice in each group. The mice in the model group and the moxibustion group were intraperitoneally injected with CTX (80 mg/kg) to induce liver injury. The mice in the moxibustion group were treated with wheat-grain moxibustion at "Guanyuan" (CV 4) and bilateral "Zusanli" (ST 36) and "Sanyinjiao" (SP 6), with each acupoint being treated by 3 cones, approximately 30 seconds per cone, once daily for 7 days. After intervention, the general condition of the mice was observed; the liver mass was measured and the liver index was calculated; HE staining was used to observe the morphology of the liver, and the liver tissue pathological score was assessed; ELISA was used to detect the serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH) and the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) in the liver; Western blot and real-time fluorescence quantitative PCR were used to detect the protein and mRNA expression of Nrf2, Keap1, and quinione acceptor oxidoreductase 1 (NQO1) in the liver. RESULTS: Compared with the blank group, the mice in the model group showed sluggishness, unsteady gait, and decreased body weight; liver index was increased (P<0.01); liver cells were loosely arranged, with a small number of cell swollen and exhibiting balloon-like changes; liver tissue pathological score was increased (P<0.05); the serum levels of AST, ALT, GLDH, and level of MDA in the liver were increased (P<0.05), and the levels of SOD and GSH-Px in the liver were decreased (P<0.05); protein and mRNA expression of Nrf2 and NQO1 in the liver was decreased (P<0.01), protein and mRNA expression of Keap1 in the liver was increased (P<0.01). Compared with the model group, the mice in the moxibustion group showed improvement in general condition; liver index was decreased (P<0.01); liver cell structure was relatively intact and clear, and liver tissue pathological score was decreased (P<0.05); the serum levels of AST, ALT, GLDH, and level of MDA in the liver were decreased (P<0.05), and the levels of SOD and GSH-Px in the liver were increased (P<0.05, P<0.01); protein and mRNA expression of Nrf2 and NQO1 in the liver was increased (P<0.05), protein and mRNA expression of Keap1 in the liver was decreased (P<0.05). CONCLUSION: The wheat-grain moxibustion may alleviate CTX-induced liver injury by activating the Nrf2-Keap1 signaling pathway and enhancing the expression of antioxidative enzyme system in the body.