Nrf2 Inhibitor Research Articles

Ginkgo Flavone Aglycone Ameliorates Atherosclerosis via Inhibiting Endothelial Pyroptosis by Activating the Nrf2 Pathway.

Natural antioxidants have been shown to be effective against atherosclerosis. Ginkgo flavone aglycone (GA) has strong antioxidant properties and can protect against endothelial damage. However, the mechanisms by which GA protects against atherosclerosis remain largely unexplored. This study hopes to find the anti-atherosclerotic mechanism of GA. ApoE-/- mice fed a high-fat diet were used for modeling atherosclerosis. The efficacy of GA on mice with atherosclerosis was evaluated based on the following indicators: Oil Red O staining, Masson staining, lipid content, and apoptosis. Transmission electron microscopy, Western blot, immunofluorescence staining, and propidium iodide staining were used to analyze the effects of GA on ox-LDL-treated human aortic endothelial cells. GA activated Nrf2 by promoting the nuclear translocation of Nrf2, thereby inhibiting endothelial pyroptosis. GA prevented endothelial pyroptosis suppressed oxidative stress, and inhibited the development of atherosclerosis in ApoE-/- mice fed high-fat diets. At the cellular level, GA suppressed ox-LDL-induced pyroptosis of HAECs by reducing reactive oxygen species (ROS) levels and inhibiting NLRP3 inflammasome. Furthermore, siRNA targeting Nrf2 or ML385, an Nrf2 inhibitor, reversed these effects. GA liberated Nrf2 from Keap1 sequestration, enhanced the nuclear translocation of Nrf2 and the transcription of downstream antioxidant proteins, reinforced the antioxidant defense system, and inhibited oxidative stress, thereby preventing endothelial cell pyroptosis, and attenuating the progression of atherosclerosis. This study indicated that GA mitigated endothelial pyroptosis by modulating Keap1/Nrf2 interactions, shedding light on the potential mechanisms underlying the protective effects of natural antioxidants against atherosclerosis.

Potential of NRF2 Inhibitors-Retinoic Acid, K67, and ML-385-In Overcoming Doxorubicin Resistance in Promyelocytic Leukemia Cells.

Drug resistance is one of the major obstacles to the clinical use of doxorubicin, an extensively used chemotherapeutic drug to treat various cancers, including leukemia. Inhibition of the nuclear factor erythroid 2-related factor 2 (NRF2) seems a promising strategy to reverse chemoresistance in cancer cells. NRF2 is a transcription factor that regulates both antioxidant defense and drug detoxification mechanisms. In this study, we investigated the potential of three inhibitors of NRF2-K67, retinoic acid and ML-385-to overcome doxorubicin resistance in promyelocytic leukemia HL-60 cells. For this purpose, low-dose doxorubicin was used to establish doxorubicin-resistant HL-60/DR cells. The expression of NRF2 and its main repressor, Kelch-like ECH-associated protein 1 (KEAP1), at mRNA and protein levels was examined. HL-60/DR cells overexpressed NRF2 at mRNA and protein levels and down-regulated KEAP1 protein compared to drug-sensitive HL-60 cells. The effects of NRF2 inhibitors on doxorubicin-resistant HL-60/DR cell viability, apoptosis, and intracellular reactive oxygen species (ROS) levels were analyzed. We observed that NRF2 inhibitors significantly sensitized doxorubicin-resistant HL-60/DR cells to doxorubicin, which was associated with increased intracellular ROS levels and the expression of CAS-9, suggesting the participation of the mitochondrial-dependent apoptosis pathway. Furthermore, ML-385 inhibitor was used to study the expression of NRF2-KEAP1 pathway genes. NRF2 gene and protein expression remained unchanged; however, we noted the down-regulation of KEAP1 protein upon ML-385 treatment. Additionally, the expression of NRF2-regulated antioxidant and detoxification genes including SOD2, HMOX2, and GSS was maintained upon ML-385 treatment. In conclusion, our results demonstrated that all the studied inhibitors, namely K67, retinoic acid, and ML-385, increased the efficacy of doxorubicin in doxorubicin-resistant HL-60/DR cells, and suggested a potential strategy of combination therapy using NRF2 inhibitors and doxorubicin in overcoming doxorubicin resistance in leukemia.

A medicine and food homology formula prevents cognitive deficits by inhibiting neuroinflammation and oxidative stress via activating AEA-Trpv1-Nrf2 pathway.

Alzheimer's disease (AD) is a neurodegenerative disorder frequently accompanied by neuroinflammation and oxidative stress. The medicine and food homology (MFH) has shown potential for treating neuroinflammation and oxidative stress. This study aimed to provide a safe and efficient therapy for AD based on MFH. In this study, we develop a MFH formula consisting of egg yolk oil, perilla seed oil, raphani seed oil, cinnamon oil, and noni puree (EPRCN). To evaluate the ameliorative effects of EPRCN on AD-related symptoms, a mouse model of AD was constructed using intraperitoneal injection of scopolamine in ICR mice. Experimental results demonstrated that EPRCN supplement restored behavioral deficits and suppressed neuroinflammation and oxidative stress in the hippocampus of scopolamine-induced mice. An in vitro study was then performed using induction of Aβ(25-35) in glial (BV-2 and SW-1783) and neuron (SH-SY5Y) cell lines to examine the improvement mechanism of EPRCN on cognitive deficits. Multi-omics and in vitro studies demonstrated that these changes were driven by the anandamide (AEA)-Trpv1-Nrf2 pathway, which was inhibited by AM404 (an AEA inhibitor), AMG9810 (a Trpv1 inhibitor), and BT (an Nrf2 inhibitor). Consequently, EPRCN is an effective therapy on preventing cognitive deficits in mouse models of AD. In contrast to donepezil, EPRCN exhibits a novel modes action for ameliorating neuroinflammation. The mechanism of EPRCN on preventing cognitive deficits is mediated by improving neuroinflammation and oxidative stress via activating the AEA-Trpv1-Nrf2 pathway.

New insights into evodiamine attenuates IPEC-J2 cells pyroptosis induced by T-2 toxin - Activating Keap1-Nrf2/NF-κB signaling pathway through binding with Keap1

T-2 toxin (T-2) is a highly toxic mycotoxin with a molecular weight of 466.52 g/mol. Evodiamine (EV), an alkaloid component of Evodia, has anti-inflammation and antioxidant properties. As a receptor of oxidative stress, Keap1 with a molecular weight of 70 kDa, is a molecular switch that controls the Nrf2 signaling pathway. In this paper, the effect of EV on Keap1-Nrf2/NF-κB pathway was investigated. Based on our research outcomes, it was observed that T-2 exposure substantially increased IPEC-J2 cells intracellular ROS levels and MDA accumulation, decreased SOD and CAT activities, disrupted intestinal tight junction (ZO-1, occludin, and claudin-1), and up-regulated pyroptosis-related protein (ASC, NLRP3, caspase-1, GSDMD, IL-1β, and IL-18). Additionally, EV could bind well with Keap1, the separating it from Nrf2, promoting Nrf2 into the nucleus, enhanced antioxidant enzyme activities, reduced the production of ROS, down-regulated NF-κB expression, alleviated T-2-induced pyroptosis, and restored tight junction protein expression. However, after treatment with the Nrf2 inhibitor ML385, ML385 reversed the protective effect of EV on IPEC-J2 cells. Collectively, EV can activate the Keap1-Nrf2/NF-κB signaling pathway via binding to Keap1, exert anti-inflammatory and antioxidant effects, inhibit the pyroptosis of IPEC-J2 cells triggered by T-2, and retore intestinal barrier function.

State-of-the-Art Nrf2 Inhibitors: Therapeutic Opportunities in Non-Cancer Diseases.

Nuclear factor erythroid 2-related factor (Nrf2) is 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 in in vitro and/or in vivo disease 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.

Procyanidin B1 Promotes PSMC3-NRF2 Ubiquitination to Induce Ferroptosis in Glioblastoma.

NRF2 signaling is a crucial antioxidant defense mechanism against ferroptosis in tumors, and targeting NRF2 is essential for tumor therapy. However, the effectiveness of NRF2 inhibitors remains unexplored. The active ingredients of traditional Chinese medicine serve as important sources of NRF2 inhibitors. In this study, we established an intracranial glioblastoma (GBM) orthotopic model and observed the effects of procyanidin B1 on tumor growth and ferroptosis. Using protein-small-molecule docking, z-stack assay of laser confocal imaging, surface plasmon resonance assay, immunoprecipitation, mass spectrometry, and western blotting, we detected the binding between procyanidin B1 and NRF2 and the effect of PSMC3 on the ubiquitin-dependent degradation of NRF2 in GBM cells. Our results showed that procyanidin B1 acted as a novel NRF2 inhibitor to suppress GBM cell proliferation and prolonged the survival of GBM-bearing mice; it also mediated the interaction between PSMC3 and NRF2 to promote ubiquitin-dependent protein degradation of NRF2, which induced ferroptosis in GBM cells. In addition, we found that procyanidin B1 enhanced H₂O₂ accumulation by downregulating NRF2 during ferroptosis in GBM cells. The botanical agent procyanidin B1 induced ferroptosis and exerted anti-tumor effects through PSMC3-mediated ubiquitin-dependent degradation of NRF2 proteins, providing a potential drug candidate for adjuvant therapy in patients with GBM.

Melatonin mitigates doxorubicin induced chemo brain in a rat model in a NRF2/p53–SIRT1 dependent pathway

Cancer is a critical health problem, and chemotherapy administration is mandatory for its eradication. However, chemotherapy like doxorubicin (Dox) has serious side-effects including cognitive impairment or chemo brain. Melatonin is a neuroprotective agent that has antioxidant, and anti-inflammatory effects. We aimed to explore melatonin's effect on Dox-induced chemo brain to discover new mechanisms associated with Dox-induced neurotoxicity and try to prevent its occurrence. Thirty-two male albino rats had been equally divided into four groups; control, melatonin-administrated, Dox-induced chemo brain, and melatonin + Dox treated. On the 9th day, brain had been excised after scarification and had been assessed for reactive oxygen species measurement, histopathological analysis, immunohistochemical, gene and protein expressions for the nuclear factor erythroid 2-related factor 2 (Nrf2), p53 and Silent information regulator 2 homolog 1 (SIRT1). Our results show that melatonin coadministration diminished Dox induced hippocampal and prefrontal cortex (PFC) cellular degeneration. It alleviated Nitric Oxide (NO) level and reversed the decline of antioxidant enzyme activities. It also upregulated Nrf2, SIRT1 and downregulated p53 gene expression in rats receiving Dox. Moreover, melatonin elevated the protein expression level of Nrf2, SIRT1 and reduced p53 corresponding to immunohistochemical results. The data suggested that melatonin can mitigate Dox-induced neurotoxicity by aggravating the endogenous antioxidants and inducing neurogenesis through activation of Nrf2/p53–SIRT1signaling pathway in adult rats' PFC. These effects were associated with Nrf2, SIRT1 activation and p53 inhibition. This could be guidance to add melatonin as an adjuvant supplement to Dox regimens to limit its adverse effect on the brain function.

Corynoline alleviates hepatic ischemia-reperfusion injury by inhibiting NLRP3 inflammasome activation through enhancing Nrf2/HO-1 signaling.

Corynoline has displayed pharmacological effects in reducing oxidative stress and inflammatory responses in many disorders. However, its effects on hepatic ischemia-reperfusion (I/R) injury remain unclear. This study aimed to investigate the protective effects of corynoline against hepatic I/R injury and the underlying mechanisms. Rat models with hepatic I/R injury and BRL-3A cell models with hypoxia/reoxygenation (H/R) insult were constructed. Models were pretreated with corynoline and/or other inhibitors for functional and mechanistic examination. Corynoline pretreatment effectively mitigated hepatic I/R injury verified by reduced serum transaminase levels, improved histological damage scores, and decreased apoptosis rates. Additionally, corynoline pretreatment significantly inhibited I/R-triggered oxidative stress and inflammatory responses, as indicated by enhanced mitochondrial function, reduced levels of ROS and MDA, reduced neutrophil infiltration and suppressed proinflammatory cytokine release. In vitro experiments further showed that corynoline pretreatment increased cellular viability, decreased LDH activity, reduced cellular apoptosis, and inhibited oxidative stress and inflammatory injury in H/R-induced BRL-3A cells. Mechanistically, corynoline significantly increased Nrf2 nuclear translocation and expression levels of its target gene, HO-1. It also blocked NLRP3 inflammasome activation both in vivo and in vitro. Furthermore, pretreatment with Nrf2 inhibitor ML-385 counteracted the protective effect of corynoline on hepatic I/R injury. Ultimately, in vitro studies revealed that the NLRP3 activator nigericin could also nullified the protective effects of corynoline in BRL-3A cells, but had minimal impact on Nrf2 nuclear translocation. Corynoline can exert protective effects against hepatic I/R injury by inhibiting oxidative stress, inflammatory responses, and apoptosis. These effects may be associated with inhibiting ROS-induced NLRP3 inflammasome activation by enhancing Nrf2/HO-1 signaling. These data provide new understanding about the mechanism of corynoline action, suggesting it is a potential drug applied for the treatment and prevention of hepatic I/R injury.

Activation of the Nrf2/Keap1 signaling pathway mediates the neuroprotective effect of Perillyl alcohol against cerebral hypoxic-ischemic damage in neonatal rats

ABSTRACT Neonatal hypoxic-ischemic encephalopathy (HIE) is a severe disease with a poor prognosis, whose clinical treatment is still limited to therapeutic hypothermia with limited efficacy. Perillyl alcohol (POH), a natural monoterpene found in various plant essential oils, has shown neuroprotective properties, though its effects on HIE are not well understood. This study investigates the neuroprotective effects of POH on HIE both in vitro and in vivo. We established an in vitro model using glucose deprivation and hypoxia/reperfusion (OGD/R) in PC12 cells, alongside an in vivo model via the modified Rice-Vannucci method. Results indicated that POH acted as an indirect antioxidant, reducing inducible nitric oxide synthase and malondialdehyde production, maintaining content of antioxidant molecules and enzymes in OGD/R-induced PC12 cells. In vivo, POH remarkably lessened infarct volume, reduced cerebral edema, accelerated tissue regeneration, and blocked reactive astrogliosis after hypoxic-ischemic brain injury. POH exerted antiapoptotic activities through both the intrinsic and extrinsic apoptotic pathways. Mechanistically, POH activated Nrf2 and inactivated its negative regulator Keap1. The use of ML385, a Nrf2 inhibitor, reversed these effects. Overall, POH mitigates neuronal damage in HIE by combating oxidative stress, reducing inflammation, and inhibiting apoptosis via the Nrf2/Keap1 pathway, suggesting its potential for HIE treatment.

Artemisinin conferred cytoprotection to human retinal pigment epithelial cells exposed to amiodarone-induced oxidative insult by activating the CaMKK2/AMPK/Nrf2 pathway

BackgroundOcular toxicity is a severe adverse effect that limits the chronic clinical use of the antiarrhythmic drug amiodarone. Here, we aimed to evaluate the cytoprotective effect of artemisinin and explore the potential signalling pathways in human retinal pigment epithelial (RPE) cell cultures.MethodsD407 cell cultures were exposed to amiodarone and the impact of artemisinin was evaluated. The key parameters included lactate dehydrogenase (LDH) release, intracellular reactive oxygen species (ROS) generation, and the mitochondrial membrane potential (MMP). We also assessed the protein levels of cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), phosphorylated adenosine monophosphate-activated protein kinase (AMPK)ɑ (p-AMPK), calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2), and nuclear factor erythroid 2-related factor 2 (Nrf2).ResultsArtemisinin reduced the cytotoxicity induced by amiodarone, as reflected by decreased LDH release, ROS generation, and MMP disruption. Additionally, artemisinin increased p-AMPK, CaMKK2, and Nrf2 protein levels. Inhibition of AMPK, CaMKK2, or Nrf2 abolished the cytoprotective effect of artemisinin. AMPK activation and Nrf2 knockdown further supported its protective role.ConclusionsArtemisinin protected RPE cells from amiodarone-induced damage via the CaMKK2/AMPK/Nrf2 pathway. The in vivo experiments in mice confirmed its efficacy in preventing retinal injury caused by amiodarone. These results suggest that an artemisinin-based eye formulation could be repurposed for treating amiodarone-induced ocular toxicity.

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.

Glucose metabolite methylglyoxal induces vascular endothelial cell pyroptosis via NLRP3 inflammasome activation and oxidative stress in vitro and in vivo

Methylglyoxal (MGO), a reactive dicarbonyl metabolite of glucose, plays a prominent role in the pathogenesis of diabetes and vascular complications. Our previous studies have shown that MGO is associated with increased oxidative stress, inflammatory responses and apoptotic cell death in endothelial cells (ECs). Pyroptosis is a novel form of inflammatory caspase-1-dependent programmed cell death that is closely associated with the activation of the NOD-like receptor 3 (NLRP3) inflammasome. Recent studies have shown that sulforaphane (SFN) can inhibit pyroptosis, but the effects and underlying mechanisms by which SFN affects MGO-induced pyroptosis in endothelial cells have not been determined. Here, we found that SFN prevented MGO-induced pyroptosis by suppressing oxidative stress and inflammation in vitro and in vivo. Our results revealed that SFN dose-dependently prevented MGO-induced HUVEC pyroptosis, inhibited pyroptosis-associated biochemical changes, and attenuated MGO-induced morphological alterations in mitochondria. SFN pretreatment significantly suppressed MGO-induced ROS production and the inflammatory response by inhibiting the NLRP3 inflammasome (NLRP3, ASC, and caspase-1) signaling pathway by activating Nrf2/HO-1 signaling. Similar results were obtained in vivo, and we demonstrated that SFN prevented MGO-induced oxidative damage, inflammation and pyroptosis by reversing the MGO-induced downregulation of the NLRP3 signaling pathway through the upregulation of Nrf2. Additionally, an Nrf2 inhibitor (ML385) noticeably attenuated the protective effects of SFN on MGO-induced pyroptosis and ROS generation by inhibiting the Nrf2/HO-1 signaling pathway, and a ROS scavenger (NAC) and a permeability transition pore inhibitor (CsA) completely reversed these effects. Moreover, NLRP3 inhibitor (MCC950) and caspase-1 inhibitor (VX765) further reduced pyroptosis in endothelial cells that were pretreated with SFN. Collectively, these findings broaden our understanding of the mechanism by which SFN inhibits pyroptosis induced by MGO and suggests important implications for the potential use of SFN in the treatment of vascular diseases.

Asiaticoside ameliorates uterine injury induced by zearalenone in mice by reversing endometrial barrier disruption, oxidative stress and apoptosis

Zearalenone (ZEA) is a mycotoxin produced by Fusarium fungi that has been shown to have adverse effects on human and animal health, particularly on the fertility of females. As a saponin derived from the medicinal plant Centella asiatica, asiaticoside (AS) has multiple bioactivities. This study aimed to investigate the protective effects of AS on ZEA-induced uterine injury and the underlying mechanism. In the present study, we demonstrated that AS could rescue ZEA-induced uterine histopathological damage and modulate the secretion of sex hormones, including progesterone (P4), luteinizing hormone (LH), and estradiol (E2), in ZEA-treated mice. Moreover, AS alleviated ZEA-induced damage to endometrial barrier function by upregulating the expression of tight junction proteins (ZO-1, occludin, and claudin-3). Further mechanistic investigations indicated that ZEA reduces the antioxidant capacity of uterine tissues, whereas AS improves the antioxidant capacity through activating the Nrf2 signaling pathway. Most notably, the protective effect of AS was blocked in Nrf2 gene knockout (Nrf2−/−) mice. Moreover, the p38/ERK MAPK pathway has been implicated in regulating ZEA toxicity and the beneficial effect of AS. Additionally, an Nrf2 inhibitor (ML385) weaken the suppressive effect of AS on the oxidative stress and MAPK pathway. AS also inhibits ZEA-induced apoptosis in uterine tissues via the PI3K/Akt signaling pathway. However, when the PI3K small molecule inhibitor LY294002 was co-administered, the ability of AS to suppress the expression of apoptosis-related proteins and inhibit ZEA-induced apoptosis decreased. Collectively, these findings reveal the involvement of multiple pathways and targets in the protective effect of AS against ZEA-induced uterine injury, providing a new perspective for the application of AS and the development of a ZEA antidote.

Targeted inhibition of NRF2 reduces the invasive and metastatic ability of HIP1 depleted lung cancer cells

BackgroundNon-Small Cell Lung Cancer (NSCLC) presents as a highly metastatic disease with Kras and P53 as prevalent oncogenic driver mutations. Endocytosis, through its role in receptor recycling and enrichment, is important for cancer cell proliferation and metastasis. Huntingtin Interacting Protein 1 (HIP1) is a clathrin mediated endocytic adapter protein found overexpressed in different cancers. However, conflicting roles both as a tumour promoter and suppressor are reported. HIP1 expression is found repressed at advanced stages and some HIP1-ALK fusions are reported in NSCLC patients. However, the molecular mechanisms and implications of HIP1 depletion are not completely understood. MethodsHIP1 depletion was performed using siRNA transient transfection and validated using immunoblotting for each experiment. Gene expression dataset from TCGA, GTEX and GEO databases was analysed to explore HIP1 expression in Lung cancer patients. Kaplan–Meier Plotter database was used to analyse the survival correlation between HIP1 mRNA expression in lung cancer patients. HIP1 depleted A549 cells were analysed for deregulated global proteome using label-free LC-MS and this data is available via ProteomeXchange with identifier PXD054307. Various functional assays such as matrigel based invasion, trans-well migration, soft agar colony and angiogenesis tube formation were performed after HIP1 depletion. NRF2 inhibitor was used after HIP1 knockdown to assess its effect on invasion and soft agar colony formation. ResultsIn silico analysis of HIP1 transcript expression reveals that it is reduced in high-grade and metastatic lung cancer patients correlating with poor survival. Global proteome profiling reveals that HIP1 depleted A549 cells are enriched in pathways associated with metabolism, proliferation and survival. Molecular and functional analysis indicate higher invasive ability of HIP1 depleted cells. The secretome from HIP1 depleted cells also increases the angiogenic potential of HUVEC cells. NRF2 inhibition significantly reverses invasion of HIP1 depleted NSCLC cells with different driver mutations. ConclusionOur study shows that HIP1 depletion leads to activation of various molecular pathways responsible for cell proliferation and survival. Additionally, enhancement of invasion and anchorage-independent growth in HIP1 depleted subsets of NSCLC cells is via upregulation of NRF2 and can be reversed by its inhibitor.

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

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

Salidroside alleviates simulated microgravity-induced bone loss by activating the Nrf2/HO-1 pathway

BackgroundBone loss caused by microgravity exposure presents a serious threat to the health of astronauts, but existing treatment strategies have specific restrictions. This research aimed to investigate whether salidroside (SAL) can mitigate microgravity-induced bone loss and its underlying mechanism.MethodsIn this research, we used hindlimb unloading (HLU) and the Rotary Cell Culture System (RCCS) to imitate microgravity in vivo and in vitro.ResultsThe results showed that salidroside primarily enhances bone density, microstructure, and biomechanical properties by stimulating bone formation and suppressing bone resorption, thereby preserving bone mass in HLU rats. In MC3T3-E1 cells cultured under simulated microgravity in rotary wall vessel bioreactors, the expression of osteogenic genes significantly increased after salidroside administration, indicating that salidroside can promote osteoblast differentiation under microgravity conditions. Furthermore, the Nrf2 inhibitor ML385 diminished the therapeutic impact of salidroside on microgravity-induced bone loss. Overall, this research provides the first evidence that salidroside can mitigate bone loss induced by microgravity exposure through stimulating the Nrf2/HO-1 pathway.ConclusionThese findings indicate that salidroside has great potential for treating space-related bone loss in astronauts and suggest that Nrf2/HO-1 is a viable target for counteracting microgravity-induced bone damage.

Hydrogen attenuates ischaemia–reperfusion injury in skeletal muscles post-limb replantation by activating the NRF2/HO-1 signalling pathway to reduce BAX expression

BackgroundIschaemia–reperfusion injury (IRI) is a critical complication post-limb replantation. The oxidative stress and cellular apoptosis due to IRI considerably hinder the healing process. This study aimed to investigate the modulatory effects of pre-perfusion with hydrogen-rich heparin sodium on the nuclear factor erythroid 2–related factor 2 (NRF2)/haeme oxygenase-1 (HO-1) pathway and its potential mechanisms in mitigating skeletal muscle IRI post-limb replantation. MethodsForty healthy Sprague–Dawley rats (250–300 g) were classified into five groups (n = 8 each): normal control, IRI + heparin sodium pre-perfusion (heparin group), IRI + hydrogen-rich heparin sodium pre-perfusion (hydrogen-rich heparin group), IRI + hydrogen-rich heparin sodium pre-perfusion + NRF2 inhibitor (hydrogen-rich heparin + all-trans retinoic acid [ATRA] group), and IRI + heparin sodium pre-perfusion + NRF2 inhibitor (heparin + ATRA group). The activation of the NRF2/HO-1 pathway in skeletal muscle IRI was evaluated based on HO-1 expression using western blotting and immunofluorescence. Furthermore, haematoxylin and eosin staining and transmission electron microscopy were employed to determine the histopathological characteristics. Additionally, superoxide dismutase and malondialdehyde levels in skeletal muscle tissue were measured to assess antioxidant capacity and the degree of oxidative stress damage. Tissue hypoxia was assessed based on hypoxia-inducible factor 1-alpha expression, whereas apoptosis markers BCL-2-associated X protein (BAX) and Caspase-3 in skeletal muscle tissues were analysed using western blotting with terminal deoxynucleotidyl transferase dUTP nick end labelling staining to quantify cell apoptosis. ResultsCompared with the control group, the heparin group exhibited significant pathological changes, including inflammatory infiltration and cellular hypertrophy, with increased apoptosis and oxidative stress. Notably, NRF2 suppression aggravated these effects. However, hydrogen-rich heparin sodium prominently activated the NRF2/HO-1 pathway, enhancing antioxidant defence and reducing BAX/Caspase-3-mediated apoptosis, thereby mitigating IRI-induced damage. The use of an NRF2 inhibitor to inhibit NRF2 excitation by hydrogen-rich heparin sodium notably weakened NRF2 activation and the antioxidant response, resulting in a substantial increase in cellular apoptosis. ConclusionPre-perfusion with hydrogen-rich heparin sodium markedly diminishes the BAX/Caspase-3-mediated apoptotic pathway in skeletal muscle tissues with IRI through the excitation of the NRF2/HO-1 pathway.

Nrf2 Deficiency Exacerbates Parkinson's Disease by Aggravating NLRP3 Inflammasome Activation in MPTP-Induced Mouse Models and LPS-Induced BV2 Cells.

Parkinson's disease (PD) is a movement disorder characterized by the progressive loss of dopamine neurons. Microglia-mediated neuroinflammation drives disease progression and becomes a critical factor in neuronal degeneration. Recent studies have found that nuclear factor-erythroid 2-related-2 (Nrf2) expression levels are reduced during aging and neurodegenerative diseases, but its regulatory mechanism on microglia-induced neuroinflammation has not been fully elucidated. In vivo, we used the intraperitoneal injection of the neurotoxic drug neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to establish an animal model of PD and, at the same time, administered Nrf2 inhibitors ML385 and dimethyl fumarate to regulate Nrf2 protein levels. In vitro, we used si-RNA to knock out the Nrf2 gene to intervene in BV2 cells and used lipopolysaccharide (LPS) to stimulate and induce the cell model. The study found that inhibition of Nrf2 expression aggravated the motor defects of PD mice, accompanied by a significant loss of dopaminergic neurons in the substantia nigra and striatum of the brain. In addition, after inhibition of Nrf2, the malondialdehyde (MDA) level in the substantia nigra of the midbrain of mice increased, and the levels of superoxide dismutase (SOD) and heme oxygenase-1 (HO-1) decreased, accompanied by the proliferation of microglia and astrocytes. In addition, the activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome, the assembly of apoptosis-associated speck-like protein containing a CARD (ASC) protein in microglia, and the release of downstream inflammatory factors caspase-1 and interleukin (IL)-1β, were aggravated. At the cellular level, it was found that knocking out the expression of Nrf2 would aggravate the activation of NLRP3 inflammasomes and the assembly of ASC in LPS-induced BV2 cells. Inhibited Nrf2 activity can reduce the downstream antioxidant enzyme HO-1 and antioxidant levels, induce NLRP3 inflammasome activation and ASC protein assembly in microglia, and ultimately aggravate PD inflammatory response and dopamine neuron degeneration.

NBQX mediates ventricular fibrillation susceptibility in rat models of anxiety via the Nrf2/HO-1 pathway

ObjectiveAnxiety disorder (AD) is a common mental disorder related to cardiovascular disease morbidity. Oxidative stress plays a crucial role in the anxiety state and can lead to cardiac remodeling. Over-activation of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) in cardiomyocytes and neurons can cause oxidative stress. Additionally, the AMPAR inhibitor—2,3-dihydroxy-6-nitro-7-sulfamoyl-benzoquinoxaline-2,3-dione (NBQX) plays an important role in ameliorating oxidative stress. This study aimed to explore the anti-arrhythmic effects of NBQX in a rat model of anxiety. MethodsThe AD model was induced using empty bottle stimulation. Male Sprague Dawley rats were randomly divided into four groups: control + saline, control + NBQX, AD + saline, and AD + NBQX. Open field test was conducted to measure anxiety-like behavior. Electrophysiological experiments, histological analysis, biochemical detection and molecular biology were performed to verify the effects of NBQX on the amelioration of electrical remodeling and structural remodeling. Furthermore, the nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor (ML385) was used in vitro to demonstrate the signaling pathway. ResultsOxidative stress levels increased with AMPAR over-activation in AD rats, leading to heightened vulnerability to ventricular fibrillation (VF). NBQX reverses anxiety and VF susceptibility. Our results showed that NBQX activated the Nrf2/heme oxygenase-1 (HO-1) pathway, leading to a decline in oxidative stress levels. Connexin 43 and ion channel expression was upregulated. NBQX treatment attenuated fibrosis and apoptosis. This effect was diminished by ML385 treatment in vitro. ConclusionNBQX can alleviate VF susceptibility in rat models of anxiety by alleviating electrical remodeling, structural remodeling via regulating the Nrf2/HO-1 pathway to some extent.

Supplementation with L-theanine promotes intestinal antioxidant ability via Nrf2 signaling pathway in weaning piglets and H2O2-induced IPEC-J2 cells

This study aimed to investigate the effect of L-theanine in regulating the intestinal antioxidant of weaned piglets and its underlying mechanism. We found that L-theanine increased the activities of antioxidant enzymes and the level of GSH, while decreased the MDA content of weaned piglet jejunum mucosa and H2O2-induced IPEC-J2 cells. In addition, the mRNA expression of SOD1, SOD2, GPx1, CAT, HO-1 and NQO1 was also significantly increased in jejunum mucosa and H2O2-induced IPEC-J2 cells by L-theanine treatment. Furthermore, L-theanine promoted the nuclear Nrf2 expression and decreased the keap1 expression. However, blocking of Nrf2 signaling by ML385 (the Nrf2 inhibitor) repressed the promoting effects of L-theanine on the activities of antioxidative enzymes and the expression of antioxidant related genes, while increased the MDA content and keap1 expression in IPEC-J2 cells. These data provided the first evidence that L-theanine improved intestinal antioxidant ability of weaned piglets by activating Nrf2 signaling pathway.