Nrf2 Inhibitor Research Articles

LncRNA H19 knockdown promotes neuropathologic and functional recovery via the Nrf2/HO-1 axis after traumatic brain injury.

Traumatic brain injury (TBI) stands as a significant concern in public health, frequently leading to enduring neurological deficits. Long non-coding RNA H19 (lncRNA H19) exerts a potential regulator role in the pathology of brain injury. This study investigates the effects of lncRNA H19 knockdown (H19-KD) on the pathophysiology of TBI and its potential neuroprotective mechanisms. Controlled cortical impact was employed to establish a stable TBI mouse model. The expression levels of various genes in perilesional cortex and striatum tissue after TBI was detected by RT-qPCR. AAV9-shRNA-H19 was injected into the lateral ventricle of mice to knockdown the expression of lncRNA H19. Various behavioral tests were performed to evaluate sensorimotor and cognitive functions after TBI. Immunofluorescence and Nissl staining were performed to assess brain tissue damage and neuroinflammation. The Nrf2 and HO-1 expression was performed by Western blot. After TBI, the expression of lncRNA H19 was elevated in perilesional tissue and gradually reverted to baseline. Behavioral tests demonstrated that H19-KD significantly promoted the recovery of sensorimotor and cognitive functions after TBI. Besides, H19-KD reduced brain tissue loss, preserved neuronal integrity, and ameliorated white matter damage at the histological level. In addition, H19-KD restrained the pro-inflammatory and facilitated anti-inflammatory phenotypes of microglia/macrophages, attenuating the neuroinflammatory response after TBI. Furthermore, H19-KD promoted activation of the Nrf2/HO-1 axis after TBI, while suppression of Nrf2 partially abolished the neuroprotective effect. H19-KD exerts neuroprotective effects after TBI in mice, partially mediated by the activation of the Nrf2/HO-1 axis.

Arsenic Trioxide Suppresses Angiogenesis in Non-small Cell Lung Cancer via the Nrf2-IL-33 Signaling Pathway.

Non-Small Cell Lung Cancer (NSCLC) ranks as a leading cause of cancer-related mortality, necessitating the urgent search for cost-effective and efficient anti-NSCLC drugs. Our preliminary research has demonstrated that arsenic trioxide (ATO) significantly inhibits NSCLC angiogenesis, exerting anti-tumor effects. In conjunction with existing literature reports, the Nrf2-IL-33 pathway is emerging as a novel mechanism in NSCLC angiogenesis. This study aimed to elucidate whether ATO can inhibit NSCLC angiogenesis through the Nrf2-IL-33 pathway. Immunohistochemistry was employed to assess the expression of Nrf2, IL-33, and CD31 in tumor tissues from patients with NSCLC. DETA-NONOate was used as a nitric oxide (NO) donor to mimic high levels of NO in the tumor microenvironment. Western blot, quantitative real-time PCR, and enzyme-linked immunosorbent assay were utilized to evaluate the expression of Nrf2 and IL-33 in the NCI-H1299 cell line. Subcutaneous xenograft models were established in nude mice by implanting NCI-H1299 cells to assess the anti-tumor efficacy of ATO. High expression levels of Nrf2 and IL-33 were observed in tumor samples from patients with NSCLC, and Nrf2 expression positively correlated with microvascular density in NSCLC. In vitro, NO (released from 1mM DETA-NONOate) promoted activation of the Nrf2-IL-33 signaling pathway in NCI-H1299 cells, which was reversed by ATO. Additionally, both Nrf2 deficiency and ATO treatment significantly attenuated NOinduced IL-33 expression. In vivo, both ATO and the Nrf2 inhibitor ML385 demonstrated significant inhibitory effects on angiogenesis tumor growth. Nrf2-IL-33 signaling is usually activated in NSCLC and positively correlates with tumor angiogenesis. ATO effectively disrupts the activation of the Nrf2-IL-33 pathway in NSCLC and thus inhibits angiogenesis, suggesting its potential as an anti-angiogenic agent for use in the treatment of NSCLC.

Reduction of the oxidative damage to H2O2-induced HepG2 cells via the Nrf2 signalling pathway by plant flavonoids Quercetin and Hyperoside

Hyperoside and quercetin are similar in molecular structures. In this study, the antioxidant regulatory targets of hyperoside and quercetin are mainly in the nuclear factor (erythroid-2-derived)-related factor 2 (Nrf2) pathway predicted by network pharmacology. And the antioxidant effect and mechanism of hyperoside and quercetin were measured and compared in H2O2-induced HepG2 cells and Caenorhabditis elegans. The findings indicated that quercetin was more effective than hyperoside in reducing oxidative damage, which was proved by improved cell viability, decreased reactive oxygen species (ROS) production, decreased cellular apoptosis, and alleviated mitochondrial damage. In addition, quercetin was more efficient than hyperoside in enhancing the expression of Nrf2-associated mRNAs, increasing the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), and reducing the cellular malondialdehyde (MDA) content. Quercetin was superior to hyperoside in prolonging the lifespan of worms, decreasing the accumulation of lipofuscin, inhibiting ROS production, and increasing the proportion of skn-1 in the nucleus. With the Nrf2 inhibitor ML385, we verified that quercetin and hyperoside primarily protected the cells against oxidative damage via the Nrf2 signalling pathway. Furthermore, molecular docking and dynamics simulations demonstrated that the quercetin- Kelch-like ECH-associated protein 1 (Keap1) complex was more stable than the hyperoside-Keap1 complex. The stable structure of the complex might hinder the binding of Nrf2 and Keap1 to release Nrf2 and facilitate its entry into the nucleus to play an antioxidant role. Overall, quercetin had a better antioxidant than hyperoside.

Taraxasterol protects against acetaminophen-induced hepatotoxicity by reducing liver inflammatory response and ameliorating oxidative stress in mice

Acute liver failure is mainly caused by the overdose of acetaminophen (APAP) globally. The traditional Chinese medicinal (TCM) herb, Taraxacum, contains Taraxasterol (TAX) as one of the active components. It is a pentacyclic-triterpene compound isolated from this herb. Present work aimed to investigate the in vitro and in vivo protection effect of TAX in APAP-induced acute liver injury, and determine the potential regulatory mechamisms. The liver injury caused by APAP is attenuated by TAX, as shown by the alleviated pathological changes of mice liver and the reduced serological indexes. TAX evidently controlled the oxidative stress and liver inflammation in mice liver. In vitro studies found that TAX reversed the decrease in LO2 cell viability induced by APAP, and protected LO2 cells from APAP-induced injury. In addition, TAX reduced the secretion of inflammatory factors in RAW264.7 macrophages as induced via APAP. Besides, TAX inhibited oxidative stress in LO2 cells induced by APAP in vitro. Noteworthy, TAX enhanced protein and mRNA expressions of Nrf2 in vivo, and knockdown of Nrf2 by using adeno-associated virus (AAV)-Nrf2-KO attenuated inhibitory impact of TAX in acute liver injury induced by APAP. Also, AAV-NRF2-KO weakened the inhibitory impact of TAX against APAP-triggered liver inflammation and oxidative stress of mice liver. Moreover, TAX activated the Nrf2 signaling in APAP-induced LO2 cells, as shown by the increased nuclear Nrf2 expression together with downstream HO-1 expression in vitro. Inhibition of Nrf2 by using ML-385, anNrf2inhibitor, weakened the inhibitory effect of TAX against APAP-induced oxidative stress and cell injury in LO2 cells. Moreover, inhibition of Nrf2 attenuated anti-inflammatory effect of TAX for APAP-induced RAW264.7 cells. Collectively, TAX could protect against APAP-triggered hepatotoxicitythrough suppression of liver oxidative stress and inflammatory response in mice.

Echinacoside activates Nrf2/PPARγ signaling pathway to modulate mitochondrial fusion-fission balance to ameliorate ox-LDL-induced dysfunction of coronary artery endothelial cells.

As a cardiovascular disease, coronary heart disease (CHD) is characterized by poor prognosis and increasing morbidity and mortalityrates. Echinacoside (ECH) can protect against multiple cardiovascular diseases due to its antioxidant and anti-inflammatory properties. However, the role of ECH in CHD remains unclear. In ECH-treated human coronary artery endothelial cells (HCAECs), cell viability, NO production, endothelial nitric oxide synthase (eNOS) expression, and angiogenesis ability were detected using cell counting kit-8 (CCK-8) assay, diaminofluorescein-FM diacetate (DAF-FM DA) staining, western blot, and tube formation assay, respectively. The activities of oxidative stress markers were detected using dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay and corresponding assay kits. Cell apoptosis was detected utilizing flow cytometry and caspase3 assay. Western blot was used to detect the expressions of Nrf2/PPARγ signaling pathway- and mitochondrial dynamics-related proteins. Mitochondrial membrane potential and mitochondrial fusion and fission were detected using JC-1 staining and immunofluorescence (IF) assay. In this study,ECH was found to revive the viability, ameliorate the endothelial dysfunction, suppress oxidative stress, and inhibit the apoptosis in ox-LDL-induced HCAECsvia activatingNrf2/PPARγ signaling pathway, which were all abolished following the treatment of Nrf2 inhibitor ML385. It was also identified that ECH regulated mitochondrial fusion-fission balance in ox-LDL-induced HCAECs through the activation of Nrf2/PPARγ signaling pathway. In summary, ECH activated Nrf2/PPARγ signaling pathway to regulate mitochondrial fusion-fission balance, thereby improving ox-LDL-induced dysfunction of HCAECs.

Red ginseng prevents doxorubicin-induced cardiomyopathy by inhibiting cell death via activating the Nrf2 pathway

BackgroundDoxorubicin (DXR) is an effective chemotherapeutic agent. DOX-induced cardiomyopathy (DICM), a major limitation of DXR, is a complication with limited treatment options. We previously reported that Red Ginseng (steamed and dried the root of Panax Ginseng cultivated for over six years; RGin) is beneficial for the treatment of DICM. However, the mechanism underlying the action of RGin remains unclear. In this study, we investigated the mechanism of action underlying the efficacy of RGin in the treatment of DICM.MethodsFour-week-old DBA/2 mice were divided into: vehicle, DXR, RGin, and DXR + RGin (n = 10/group). Mice were treated with DXR (4 mg/kg, once a week, accumulated 20 mg/kg, i.p.) or RGin (0.5 g/kg, three times a week, i.p.). To evaluate efficacy, the survival rate and left ventricular ejection fraction (LVEF) were measured as a measure of cardiac function, and cardiomyocytes were subjected to Masson trichrome staining. To investigate the mechanism of action, western blotting was performed to evaluate the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1, transferrin receptor (TfR), and other related proteins. Data were analyzed using the Easy R software. Between-group comparisons were performed using one-way analysis of variance and analyzed using a post-hoc Tukey test. Survival rates were estimated using the Kaplan–Meier method and compared using the log-rank test. P < 0.05 was considered statistically significant in all analyses.ResultsRGin treatment prolongs survival and protects against reduced LVEF. In the DXR group, Nrf2 was not activated and cell death was accelerated. Furthermore, there was an increase in the TfR levels, suggesting abnormal iron metabolism. However, the DXR + RGin group showed activation of the Nrf2 pathway and suppression of myocardial cell death. Furthermore, there was no increase in TfR expression, suggesting that there were no abnormalities in iron metabolism. Therefore, the mechanism of action of RGin in DICM involves an increase in antioxidant activity and inhibition of cell death through activation of the Nrf2 pathway.ConclusionRGin is a useful therapeutic candidate for DICM. Its efficacy is supported by the activation of the Nrf2 pathway, which enhances antioxidant activity and inhibits cell death.

Dexmedetomidine inhibits ferroptosis of human renal tubular epithelial cells by activating the Nrf2/HO-1/GPX4 pathway

To investigate the protective effect of dexmedetomidine (DEX) against erastin-induced ferroptosis in human renal tubular epithelial cells (HK-2 cells) and explore the underlying mechanism. HK-2 cells were treated with erastin alone or in combination with different concentrations (2.5, 5.0 and 10 μmol/L) of DEX, and the changes in cell viability were observed using CCK-8 assay. To explore the mechanism by which DEX inhibits erastin-induced ferroptosis, HK-2 cells were treated with erastin, erastin+10 μmol/L DEX, or erastin+10 μmol/L DEX+ML385 (a Nrf2 inhibitor), after which the cell viability was assessed. The level of intracellular Fe2+ was detected by cell ferrous iron colorimetric assay kit, and flow cytometry was performed to detect reactive oxygen species (ROS); MDA and reduced glutathione assay kits were used to detect the contents of MDA and GSH in the cells; The expressions of Nrf2, HO-1 and GPX4 proteins were detected by Western blotting. Erastin treatment significantly inhibited the viability of the cells, decreased GSH content, and increased intracellular levels of Fe2+, ROS and MDA. The combined treatment with 10 μmol/L DEX markedly increased the viability of the cells, increased GSH content, reduced the levels of Fe2+, ROS and MDA, and upregulated the protein expressions of Nrf2, HO-1 and GPX4 in the cells. The application of ML385 obviously blocked the protective effect of DEX and caused significant inhibition of the Nrf2/HO-1/GPX4 pathway, decreased the cell viability and GSH content, and increased the levels of Fe2+, ROS and MDA in HK-2 cells. The protective effect of DEX against erastin-induced ferroptosis of HK-2 cells is probably mediated by activation of the Nrf2/HO-1/GPX4 pathway to inhibit oxidative stress.

Hecogenin alleviates LPS-induced osteolysis via regulating pyroptosis and ROS involved Nrf2 activation

Reactive oxidative species (ROS) generation triggers pyroptosis and induces development of inflammatory osteolysis. Hecogenin (HG) has anti-inflammatory and antioxidative property, but its effects on inflammatory osteolysis remains unclear. In our study, we investigated the mechanism of HG on pyroptosis and its effect on inflammatory osteolysis in vitro and in vivo. The impact of HG on osteoclastogenesis was evaluated using cytotoxicity, TRAcP staining and bone resorption assays. The RNA-sequencing was employed to identify potential signaling pathways, and then RT-qPCR, western blot, immunofluorescence, and ELISA were used to verify. To determine the protective effect of HG in vivo, Lipopolysaccharide (LPS)-induced animal models were utilized, along with micro-CT and histological examination. HG suppressed RANKL-induced osteoclast differentiation, bone resorption, NFATc1 activity and downstream factors. RNA-sequencing results showed that HG inhibited osteoclastogenesis by modulating the inflammatory response and macrophage polarization. Furthermore, HG inhibited the NF-κB pathway, and deactivated the NLRP3 inflammasome. HG activated the expression of nuclear factor E2-related factor 2 (Nrf2) to eliminate ROS generation. Importantly, the inhibitory effect of HG on NLRP3 inflammasome could be reversed by treatment with the Nrf2 inhibitor ML385. In vivo, HG prevented the mice against LPS-induced osteolysis by suppressing osteoclastogenesis and inflammatory factors. In conclusion, HG could activate Nrf2 to eliminate ROS generation, inactivate NLRP3 inflammasome and inhibit pyroptosis, thereby suppressing osteoclastogenesis in vitro and alleviating inflammatory osteolysis in vivo, which indicating that HG might be a promising candidate to treat inflammatory osteolysis.

Pueraria lobata antioxidant extract ameliorates non-alcoholic fatty liver by altering hepatic fat accumulation and oxidative stress

Ethnopharmacological relevancePueraria lobata is essential medicinal and edible homologous plants widely cultivated in Asian countries. Therefore, P. lobata is widely used in the food, health products and pharmaceutical industries and have significant domestic and international market potential and research value. P. lobata has remarkable biological activities in protecting liver, relieving alcoholism, antioxidation, anti-tumor and anti-inflammation in clinic. However, the potential mechanism of ethyl acetate extract of Pueraria lobata after 70% alcohol extraction (APL) ameliorating nonalcoholic fatty liver disease (NAFLD) has not been clarified. Aim of the studyThis study aimed to investigate the ameliorative effect of P. lobata extract on human hepatoma cells and injury in rats, and to evaluate its therapeutic potential for ameliorating NAFLD. MethodsFirstly, the effective part of P. lobata extract was determined as APL by measuring its total substances and antioxidant activity. And then the in vitro and in vivo models of NAFLD were adopted., HepG2 cells were incubated with palmitic acid (PA) and hydrogen peroxide (H2O2). In order to evaluate the effect of APL, Simvastatin and Vitamin C (VC) were used as positive control. Various parameters related to lipogenesis and fatty acid β-oxidation were studied, such as intracellular lipid accumulation, reactive oxygen species (ROS), Western Blot, mitochondrial membrane potential, apoptosis, and the mechanism of APL improving NAFLD. The chemical components of APL were further determined by HPLC and UPLC-MS, and molecular docking was carried out with Keap1/Nrf2/HO-1 pathway related proteins. ResultsAPL significantly reduced lipid accumulation and levels of oxidative stress-related factors in vitro and in vivo. Immunohistochemical、Western Blot and PCR analysis showed that the expressions of Nrf2 and HO-1 were up-regulated in APL treatment. The Nrf2 inhibitor ML385 can block the rescue by APL of cellular oxidative stress and lipid accumulation induced by H2O2 and PA, demonstrating its dependence on Nrf2. UPLC/MS analysis showed that there were 3′-hydroxyl puerarin, puerarin, 3′-methoxy puerarin, daidzein, genistin, ononin, daidzin and genistein. ConclusionThis study further clarified the mechanism of P. lobata extract in improving NAFLD, which provided a scientific basis for developing new drugs to protect liver injury and laid a solid foundation for developing P. lobata Chinese herbal medicine resources.

Catechins counteracted hepatotoxicity induced by cadmium through Keap1-Nrf2 pathway regulation

Catechins, phenolic compounds renowned for their superior antioxidant and metal chelating attributes, are commonly found in foods. Cadmium (Cd) is a highly toxic heavy metal especially detrimental to the liver. However, the potential toxicologic effects of catechins against Cd-induced hepatotoxicity remains poorly studied. To investigate the preventive effects of catechins on Cd exposure, adult C57/BL6J mice were employed, receiving 100 mg/kg body weight (BW) catechins for consecutive 14 days by gavage, followed by acute exposure to 20 mg/kg BW Cd on the final day. Focusing on the liver, our findings demonstrated that catechins effectively alleviated Cd-induced hepatoxicity, including the hepatic Cd accumulation, transaminases levels in serum, inflammation and oxidative stress in the liver. By using brusatol, a Nrf2 inhibitor, the prevention of catechins was reversed, highlighting the crucial key to Kelch-like ECH-associated protein 1 (Keap1)- Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in counteracting Cd-induced hepatoxicity. Our results revealed the beneficial effect of catechins on alleviating Cd-induced hepatotoxicity through the Keap1-Nrf2 pathway, and also provided a novel insight into the beneficial properties of catechins to counteract metal toxicity.

ATF3 affects osteogenic differentiation in inflammatory hPDLSCs by mediating ferroptosis via regulating the Nrf2/HO-1 signaling pathway

Activating transcription factor 3 (ATF3) has been identified as a regulator associated with osteoblast differentiation. However, the effects of ATF3 on the osteogenic differentiation and proliferation of human periodontal stem cells (hPDLSCs) in periodontitis have not been reported. With the purpose of establishing an in vitro model of periodontitis, hPDLSCs were challenged with lipopolysaccharide (LPS). The Cell Counting Kit-8 assay was applied to assess cell viability, while reverse transcription-quantitative PCR and western blotting were employed to detect ATF3 expression. Inflammatory release was assessed using ELISA, together with western blotting. Lipid peroxidation was explored using the C11 BODIPY 581/591 probe, biochemical kits, thiobarbituric acid reactive substances (TBARS) assay and DCFH-DA staining. Iron and Fe2+ levels, and the expression levels of ferroptosis-related proteins were measured using corresponding kits and western blotting. Osteogenic differentiative capability was evaluated using alkaline phosphatase staining, Alizarin red staining and western blotting. The expression levels of proteins associated with Nrf2/HO-1 signaling were identified using western blotting. The results indicated that ATF3 expression was upregulated in LPS-induced hPDLSCs. The knockdown of ATF3 alleviated the LPS-induced inflammatory response in hPDLSCs, together with increased levels of TNF-α, IL-6, IL-1β, Cox-2 and iNOS, and decreased levels of IL-10. ATF3 silencing also led to lower TBARS production rate, and reduced levels of reactive oxygen species, iron, Fe2+, ACSL4 and TFR1, whereas it elevated the levels of SLC7A11 and GPX4. In addition, ATF3 silencing promoted hPDLSC mineralization and cell differentiation, and elevated the levels of OCN2, RUNX2 and BMP2. Additionally, ATF3 depletion upregulated the expression levels of proteins related with Nrf2/HO-1 signaling. The Nrf2 inhibitor ML385 partially counteracted the effects of ATF3 interference on the LPS-challenged inflammatory response, lipid peroxidation, ferroptosis as well as osteogenic differentiative capability in hPDLSCs. In summary, the results revealed that ATF3 silencing suppressed inflammation and ferroptosis, while it improved osteogenic differentiation in LPS-induced hPDLSCs by regulating Nrf2/HO-1 signaling, which may provide promising therapeutic targets for the treatment of periodontitis.

Downregulation of HDAC6 mitigates lung ischemia/reperfusion injury depending on activation of Nrf2/HO-1 signaling pathway and inactivation of ERK/NF-κB signaling pathway

IntroductionLung ischemia/reperfusion injury (LIRI) is a pathological process caused by the deficiency and subsequent reperfusion of oxygen and blood to the lung. Literature reports that the catalytic activity and expression of HDAC6 can be induced in response to IRI. HDAC6 inhibition confers protective effects against a series of IRI and also exerts pulmonary protection against various lung damage. The present study was formulated to investigate the functional role of HDAC6 inhibitor in LIRI and to probe into the intrinsic mechanisms underlying the protective role of HDAC6 inhibitor against LIRI. MethodsLung epithelial cell line MLE-12 cells were subjected to H/R injury to construct in vitro cell culture model of LIRI. For functional experiments, MLE-12 cells were pre-treated with various concentrations of selective HDAC6 inhibitor ACY-1215 (1, 5, 10 μM) to evaluate the biological role of HDAC6 in LIRI. For rescue experiments, MLE-12 cells were pre-treated with Nrf2 inhibitor ML385 (10 μM) or ERK activator LM22B-10 (50 μM) to discuss the molecular mechanisms. ResultsIt was verified that HDAC6 inhibition repressed H/R-induced apoptosis, oxidative stress, inflammation and mitochondrial dysfunction of MLE-12 cells. HDAC6 inhibition activated Nrf2/HO-1 signaling pathway and inactivated ERK/NF-κB signaling pathway in MLE-12 cells. The repressing effects of HDAC6 inhibition on H/R-induced apoptosis, oxidative stress, inflammation and mitochondrial dysfunction of MLE-12 cells were partially abolished upon pre-treatment with Nrf2 inhibitor ML385 or ERK activator LM22B-10. ConclusionHDAC6 inhibition may mitigate H/R-induced lung epithelial cell injury depending on activation of Nrf2/HO-1 signaling pathway and inactivation of ERK/NF-κB signaling pathway.

Isochlorogenic acid A ameliorated lead-induced anxiety-like behaviors in mice by inhibiting ferroptosis-mediated neuroinflammation via the BDNF/Nrf2/GPX4 pathways

Lead (Pb) is a common environmental neurotoxicant that causes behavioral impairments in both rodents and humans. Isochlorogenic acid A (ICAA), a phenolic acid found in a variety of natural sources such as tea, fruits, vegetables, coffee, plant-based food products, and various medicinal plants, exerts multiple effects, including protective effects on the lungs, livers, and intestines. The objective of this study was to investigate the potential neuroprotective effects of ICAA against Pb-induced neurotoxicity in ICR mice. The results indicate that ICAA attenuates Pb-induced anxiety-like behaviors. ICAA reduced neuroinflammation, ferroptosis, and oxidative stress caused by Pb. ICAA successfully mitigated the Pb-induced deficits in the cholinergic system in the brain through the reduction of ACH levels and the enhancement of AChE and BChE activities. ICAA significantly reduced the levels of ferrous iron and MDA in the brain and prevented decreases in GSH, SOD, and GPx activity. Immunofluorescence analysis demonstrated that ICAA attenuated ferroptosis and upregulated GPx4 expression in the context of Pb-induced nerve damage. Additionally, ICAA downregulated TNF-α and IL-6 expression while concurrently enhancing the activations of Nrf2, HO-1, NQO1, BDNF, and CREB in the brains of mice. The inhibition of BDNF, Nrf2 and GPx4 reversed the protective effects of ICAA on Pb-induced ferroptosis in nerve cells. In general, ICAA ameliorates Pb-induced neuroinflammation, ferroptosis, oxidative stress, and anxiety-like behaviors through the activation of the BDNF/Nrf2/GPx4 pathways.

Polygonatum polysaccharide ameliorates D-galactose-induced cognitive dysfunction in aging rats by inhibiting ferroptosis through activation of Nrf2

ContextAging is a major risk factor for various neurodegenerative diseases, and ferroptosis has been identified as an important mode of cell death during accelerated aging. As the main component of the edible plant YuZhu in China, Polygonatum polysaccharide (POP) is an important natural compound with anti-aging properties. ObjectiveTo evaluate the anti-aging effects of POP and the underlying molecular mechanisms involved and to evaluate the overall anti-aging effects of POP on cognitive impairment due to accelerated aging. Materials and methodsA D-galactose (D-gal)-induced accelerated aging rat model was established to evaluate the anti-aging effects of POP and the underlying molecular mechanisms involved. In turn, Morris water maze and open field experiments were used to evaluate the anti-aging effects of POP on cognitive impairment due to accelerated aging. ResultsThe mechanism by which POP affects nuclear factor E2-related factor 2 (Nrf2), an essential transcription factor, was confirmed. POP significantly improved d-gal-induced cognitive dysfunction in treated model rats, which exhibited reduced pathological changes in the hippocampus, reduced latency of the water maze platform, and increased exploration time in the central area in the open field experiment compared to those of untreated model rats. Furthermore, POP intervention downregulated ferroptosis-related proteins and upregulated Nrf2 expression, and selective inhibition of Nrf2 eliminated the ability of POP to reduce ferroptosis. ConclusionsPOP is a natural ingredient with therapeutic potential due to its ability to alleviate aging by activating Nrf2, inhibiting ferroptosis, and alleviating cognitive dysfunction.

The Role of Nrf2 in the Regulation of Mitochondrial Function and Ferroptosis in Pancreatic Cancer.

The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) represents the master regulator of the cellular antioxidant response and plays a critical role in tumorigenesis. This includes a preventive effect of Nrf2 on cell death through ferroptosis, which represents an essential mechanism of therapy resistance in malignant tumors, such as pancreatic ductal adenocarcinoma (PDAC) as one of the most aggressive and still incurable tumors. Addressing this issue, we provide an overview on Nrf2 mediated antioxidant response with particular emphasis on its effect on mitochondria as the organelle responsible for the execution of ferroptosis. We further outline how deregulated Nrf2 adds to the progression and therapy resistance of PDAC, especially with respect to the role of ferroptosis in anti-cancer drug mediated cell killing and how this is impaired by Nrf2 as an essential mechanism of drug resistance. Our review further discusses recent approaches for Nrf2 inhibition by natural and synthetic compounds to overcome drug resistance based on enhanced ferroptosis. Finally, we provide an outlook on therapeutic strategies based on Nrf2 inhibition combined with ferroptosis inducing drugs.

Inhibitor of apoptosis stimulating protein of p53 protects against MPP+-induced neurotoxicity of dopaminergic neurons.

Inhibitor of apoptosis stimulating protein of p53 (iASPP) is related to the pathogenesis of several neurological disorders by affecting the oxidative stress and survival of neurons. However, whether iASPP has a role in Parkinson disease (PD) remains to be determined. This work explored the potential regulatory effect of iASPP in an in vitro model of PD based on 1-methyl-4-phenylpyridinium (MPP+)-evoked neurotoxicity of dopaminergic neurons in culture. MN9D neurons were treated with MPP+ at 200 µM in the culture media for 24h to induce neurotoxicity. Overexpression and silencing of iASPP in neurons were achieved by infecting recombinant adenovirus expressing iASPP and sh-iASPP, respectively. Protein expression was examined by immunoblotting. MPP+-evoked neurotoxicity of dopaminergic neurons was determined by cell viability, TUNEL, and flow cytometric assays. The transcriptional activity of nuclear erythroid factor 2-like 2 (Nrf2) was assessed by luciferase reporter assay. Kelch-like ECH-associated protein 1 (Keap1)-knockout neurons were generated by lentiCRISPR/Cas9-Keap1 constructs. Expression levels of iASPP declined in MPP+-stimulated neurons. Overexpression of iASPP in neurons exhibited inhibitory effects on MPP+-evoked apoptosis, α-synuclein accumulation, and oxidative stress, while iASPP-deficient neurons were more sensitive to MPP+-induced neurotoxicity. Overexpression of iASPP led to an enhancing effect on Nrf2 activation in MPP+-stimulated neurons. Mechanism research revealed that iASPP may contribute to the activation of Nrf2 by competing with Nrf2 in binding with Keap1. Notably, the regulatory effect of iASPP on Nrf2 was diminished in Keap1-knockout neurons. The chemical inhibition of Nrf2 or knockdown of Nrf2 abrogated the protective effects of iASPP on MPP+-induced neurotoxicity. To conclude, iASPP protects dopaminergic neurons against MPP+-induced neurotoxicity through modulation of the Keap1/Nrf2 axis. Therefore, iASPP may play a crucial role in mediating the loss of dopaminergic neurons in PD, and targeting the iASPP-Nrf2 axis could be a promising strategy for treating PD.

Inhibition of NRF2 transcription factor mediated by MIR-155 diminishes melanoma cell viability independently of redox status

Redox-sensitive NRF2 transcription factor is a target gene of microRNA miR-155. miR-155 mimic was transfected in dacarbazine-resistant melanoma cells. NRF2 expression levels were down-regulated in miR-155-overexpressed cells independently of oxidative stress induced by hydrogen peroxide. NRF2 suppression was associated with a decrease of melanoma cells viability. As a result, miR-155-mediated NRF2 overexpression that regulate intensity of a cell antioxidant processes can be associated with cancer cell survival leading to drug resistance. NRF2 repression by miR-155 highlighted a potential for NRF2 down-regulation as an approach in anticancer therapy.

The autophagic regulation of rosiglitazone-promoted adipocyte browning.

Objective: Browning of white adipocytes is considered an efficient approach to combat obesity. Rosiglitazone induces the thermogenetic program of white adipocytes, but the underlying mechanisms remain elusive. Methods: Expression levels of browning and autophagy flux markers were detected by real-time PCR and immunoblotting. H&E and Oil Red O staining were performed to evaluate the lipid droplets area. Nuclear protein extraction and immunoprecipitation were used to detect the proteins interaction. Results: In this study, we reported that rosiglitazone promoted adipocyte browning and inhibited autophagy. Rapamycin, an autophagy inducer, reversed adipocyte browning induced by rosiglitazone. Autophagy inhibition by rosiglitazone does not prevent mitochondrial clearance, which was considered to promote adipose whitening. Instead, autophagy inhibition increased p62 nuclear translocation and stabilized the PPARγ-RXRα heterodimer, which is an essential transcription factor for adipocyte browning. We found that rosiglitazone activated NRF2 in mature adipocytes. Inhibition of NRF2 by ML385 reversed autophagy inhibition and the pro-browning effect of rosiglitazone. Conclusion: Our study linked autophagy inhibition with rosiglitazone-promoted browning of adipocytes and provided a mechanistic insight into the pharmacological effects of rosiglitazone.

The TF/Nrf2/GSTP1 pathway is involved in stress-induced hepatocellular injury through ferroptosis.

Stress triggers a comprehensive pathophysiological cascade in organisms. However, there is a substantial gap in the research regarding the effects of stress on liver function. This study aimed to investigate the impact of restraint stress on hepatocellular damage and elucidate the underlying molecular mechanisms. An effective mouse restraint stress model was successfully developed, and liver function analysis was performed using laser speckle imaging, metabolomics and serum testing. Alterations in hepatocyte morphology were assessed using haematoxylin and eosin staining and transmission electron microscopy. Oxidative stress in hepatocytes was assessed using lipid reactive oxygen species and malondialdehyde. The methylation status and expression of GSTP1 were analysed using DNA sequencing and,real-time PCR, and the expression levels of GPX4, TF and Nrf2 were evaluated using real-time quantitative PCR, western blotting, and immunohistochemical staining. A stress-induced model was established invitro by using dexamethasone-treated AML-12 cells. To investigate the underlying mechanisms, GSTP1 overexpression, small interfering RNA, ferroptosis and Nrf2 inhibitors were used. GSTP1 methylation contributes to stress-induced hepatocellular damage and dysfunction. GSTP1 is involved in ferroptosis-mediated hepatocellular injury induced by restraint stress via the TF/Nrf2 pathway. These findings suggest that stress-induced hepatocellular injury is associated with ferroptosis, which is regulated by TF/Nrf2/GSTP1.

The Nrf2/HO-1 pathway participates in the antiapoptotic and anti-inflammatory effects of platelet-rich plasma in the treatment of osteoarthritis.

We aimed to explore the molecular mechanisms through which platelet-rich plasma (PRP) attenuates osteoarthritis (OA)-induced pain, apoptosis, and inflammation. An in vivo model of OA was established by injuring rats using the anterior cruciate ligament transection method, whereas an in vitro model was generated by exposing chondrocytes to interleukin (IL)-1β. Both models were then treated with PRP. In both the in vivo and in vitro models, OA led to the suppression of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway, whereas treatment with PRP reactivated this molecular axis. Inhibition of the Nrf2/HO-1 pathway using the Nrf2 inhibitor brusatol or through Nrf2 gene silencing counteracted the effects of PRP in reducing the tenderness and thermal pain thresholds of OA rats. Additionally, PRP reduced the mRNA expression of IL-1β, IL-6, tumor necrosis factor-alpha (TNF-α), and matrix metallopeptidase 13 (MMP-13) and the protein expression of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X-protein (Bax), and caspase-3. Furthermore, inflammation and apoptosis were induced by brusatol treatment or Nrf2 silencing. Additionally, in the in vitro model, PRP treatment increased the proliferation of chondrocytes and attenuated their inflammatory response and apoptosis, effects that were abrogated by Nrf2 depletion. The Nrf2/HO-1 pathway participates in the PRP-mediated attenuation of OA development by suppressing inflammation and apoptosis.