Electroacupuncture reduces oxidative stress response and improves secondary injury of intracerebral hemorrhage in rats by activating the peroxisome proliferator-activated receptor-γ/nuclear factor erythroid2-related factor 2/γ-glutamylcysteine synthetase pathway

Intracerebral hemorrhage (ICH) is a severe stroke subtype. Secondary injury is a key factor leading to neurological deficits after ICH. Electroacupuncture (EA) can improve the neurological function after ICH, however, its internal mechanism is still unclear. The aim of this study is to investigate whether EA could ameliorate secondary injury after ICH through antioxidative stress and its potential regulatory mechanism. A rat model of ICH was established by injecting autologous blood into striatum. After the intervention of EA and EA combined with peroxisome proliferator-activated receptor-γ (PPARγ) blocker, Zea-longa scores, modified neurological severity scores and open field tests were used to evaluate the neurological function of the rats. Flow cytometry detected tissue reactive oxygen species (ROS) levels. Tissue tumor necrosis factor-α (TNF-α) levels were analyzed by enzyme-linked immunosorbent assays. The protein expressions of PPAR γ, nuclear factor erythroid2-related factor 2 (Nrf2) and γ-glutamylcysteine synthetase (γ-GCS) were detected by Western blot. Immunohistochemistry was used to observe the activation of microglia. The demyelination degree of axon myelin was observed by transmission electron microscope. Compared with the model group, EA intervention improved neurological function, decreased ROS and TNF-α levels, increased the protein expression of PPARγ, Nrf2 and γ-GCS, and reduced the activation of microglia, it also alleviated axonal myelin sheath damage. In addition, the neuroprotective effect of EA was partially attenuated by PPARγ blocker. EA ameliorated the neurological function of secondary injury after ICH in rats, possibly by activating the PPARγ/Nrf2/γ-GCS signaling pathway, reducing microglia activation, and inhibiting oxidative stress, thus alleviating the extent of axonal demyelination plays a role.

Nrf2-Keap1 in Cardiovascular Disease: Which is the Cart and Which the Horse?

High levels of oxidant stress in the form of reactive oxidant species (ROS) are prevalent in the circulation and tissues in various types of cardiovascular disease including heart failure, hypertension, peripheral arterial disease, and stroke. Here we review the role of nuclear factor erythroid 2-related factor 2 (Nrf2), an important and widespread antioxidant and anti-inflammatory transcription factor that may contribute to the pathogenesis and maintenance of cardiovascular diseases. We review studies showing that downregulation of Nrf2 exacerbates heart failure, hypertension and autonomic function. Finally, we discuss the potential for using Nrf2 modulation as a therapeutic strategy for cardiovascular diseases and autonomic dysfunction.

Diroximel fumarate acts through Nrf2 to attenuate methylglyoxal-induced nociception in mice and decreases ISR activation in DRG neurons

Diabetic neuropathic pain is associated with elevated plasma levels of methylglyoxal (MGO). MGO is a metabolite of glycolysis that causes mechanical hypersensitivity in mice by inducing the integrated stress response (ISR), which is characterized by phosphorylation of eukaryotic initiation factor 2α (p-eIF2α). Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates the expression of antioxidant proteins that neutralize MGO. We hypothesized that activating Nrf2 using diroximel fumarate (DRF) would alleviate MGO-induced pain hypersensitivity. We pretreated male and female C57BL/6 mice daily with oral DRF prior to intraplantar injection of MGO (20 ng). DRF (100 mg/kg) treated animals were protected from developing MGO-induced mechanical and cold hypersensitivity. Using Nrf2 knockout mice we demonstrate that Nrf2 is necessary for the anti-nociceptive effects of DRF. In cultured mouse and human dorsal root ganglion (DRG) sensory neurons, we found that MGO induced elevated levels of p-eIF2α. Co-treatment of MGO (1 μM) with monomethyl fumarate (MMF, 10, 20, 50 μM), the active metabolite of DRF, reduced p-eIF2α levels and prevented aberrant neurite outgrowth in human DRG neurons. Our data show that targeting the Nrf2 antioxidant system with DRF is a strategy to potentially alleviate pain associated with elevated MGO levels.

Tuning the Reactivity of Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) Activators for Optimal in Vivo Efficacy

Dimethyl fumarate 1 is approved for the treatment of multiple sclerosis but is also associated with off-target activation of the niacin receptor. By using a tetrazolone or triazolone bioisostere approach to the fumarate and vinyl sulfone series of Nrf2 activators, we have optimized the electrophilicity of the double bond to tune the on-target Nrf2 activation with PK properties to achieve efficacy in animal models of multiple sclerosis. The study linked highly potent, highly electrophilic molecules to low plasma stability and, subsequently, limited efficacy. By contrast, a sulfonylvinyltriazolone 17 retains on-target potency but shows much weaker electrophilic potential. As a consequence, in vivo high exposures of 17 are obtained, resulting in efficacy in the EAE model similar to that observed for DMF. 17 (R079) is Ames negative, is not cytotoxic to cells, and shows little inhibition of either the niacin receptor or a panel of off-target receptors.

Pre-treatment with galectin-1 attenuates lipopolysaccharide-induced myocarditis by regulating the Nrf2 pathway

Galectin-1 (Gal-1), a member of a highly conserved family of animal lectins, plays a crucial role in controlling inflammation and neovascularization. However, the potential role of Gal-1 in preventing myocarditis remains uncertain. We aimed to explore the functions and mechanisms of Gal-1 in preventing myocarditis. In vivo, C57/BL6 mice were pre-treated with or without Gal-1 and then exposed to lipopolysaccharide (LPS) to induce myocarditis. Subsequently, cardiac function, histopathology, inflammation, oxidative stress, and apoptosis of myocardial tissues were detected. Following this, qRT-PCR and Western blotting were applied to measure iNOS, COX2, TXNIP, NLRP3 and Caspase-1 p10 expressions. In vitro, H9c2 cells pre-treated with different doses of Gal-1 were stimulated by LPS to induce myocarditis models. CCK8, flow cytometry and reactive oxygen species (ROS) assay were then employed to estimate cell viability, apoptosis and oxidative stress. Furthermore, Nrf2 and HO-1 protein expressions were evaluated by Western blotting in vivo and in vitro. The results showed that in vivo, Gal-1 pre-treatment not only moderately improved cardiac function and cardiomyocyte apoptosis, but also ameliorated myocardial inflammation and oxidative damage in mice with myocarditis. Furthermore, Gal-1 inhibited TXNIP-NLRP3 inflammasome activation. In vitro, Gal-1 pre-treatment prevented LPS-induced apoptosis, cell viability decrease and ROS generation. Notably, Gal-1 elevated HO-1, total Nrf2 and nuclear Nrf2 protein expressions both in vivo and in vitro. In conclusion, pre-treatment with Gal-1 exhibited cardioprotective effects in myocarditis via anti-inflammatory and antioxidant functions, and the mechanism may relate to the Nrf2 pathway, which offered new solid evidence for the use of Gal-1 in preventing myocarditis.

Expression of Ferroptosis-Related Proteins Glutathione Peroxidase 4, Nuclear Factor Erythroid 2-Related Factor 2, and Solute Carrier Family 7 Member 11 in Gastric Cancer Patients

BACKGROUND/AIMS

The aim of this study was to investigate the expression of ferroptosis-related targets glutathione peroxidase 4, nuclear factor erythroid 2-related factor 2, and solute carrier family 7 member 11 in gastric cancer and the correlation between their expression and the clinicopathological characteristics and prognosis of gastric cancer patients.

MATERIALS AND METHODS

Forty-two gastric cancer samples and paracancerous samples were included, and all cases were detected with glutathione peroxidase 4, nuclear factor erythroid 2-related factor 2, and solute carrier family 7 member 11 by immunohistochemistry. Six gastric cancer cell lines and 1 normal gastric epithelial cell were stably cultured, and the expression of target genes of different cell lines was detected using western blot and polymerase chain reaction. Public data were downloaded from the database, and analyses were performed by software including Statistical Package for the Social Sciences and Prism.

RESULTS

A high glutathione peroxidase 4 expression level was found in 7 (16.67%) cancer tissues and 0 (0.00%) paracancerous tissues (P = .012). Nuclear factor erythroid 2-related factor 2 was upregulated in 23 (54.76%) cancer tissues and 2 (4.76%) paracancerous tissues (P < .001). Solute carrier family 7 member 11 showed increased expression in 4 (9.52%) cancer tissues and 1 (2.38%) paracancerous tissue (P = .356). No significant association existed between their expression and the clinicopathological characteristics and prognosis of gastric cancer patients. Glutathione peroxidase 4 and nuclear factor erythroid 2-related factor 2 expressions were higher in all 6 gastric cancer cell lines compared to normal gastric epithelial cells.

CONCLUSION

Glutathione peroxidase 4 and nuclear factor erythroid 2-related factor 2 expressions were significantly higher in gastric cancer, which may be potential biomarkers of gastric cancer.

Effects of oxidative stress regulation in inflammation-associated gastric cancer progression treated using traditional Chinese medicines: A review

Gastric cancer (GC) is a global public health concern that poses a serious threat to human health owing to its high morbidity and mortality rates. Due to the lack of specificity of symptoms, patients with GC tend to be diagnosed at an advanced stage with poor prognosis. Therefore, the development of new treatment methods is particularly urgent. Chronic atrophic gastritis (CAG), a precancerous GC lesion, plays a key role in its occurrence and development. Oxidative stress has been identified as an important factor driving the development and progression of the pathological processes of CAG and GC. Therefore, regulating oxidative stress pathways can not only intervene in CAG development but also prevent the occurrence and metastasis of GC and improve the prognosis of GC patients. In this study, PubMed, CNKI, and Web of Science were used to search for a large number of relevant studies. The review results suggested that the active ingredients of traditional Chinese medicine (TCM) and TCM prescriptions could target and improve inflammation, pathological status, metastasis, and invasion of tumor cells, providing a potential new supplement for the treatment of CAG and GC.

Oxidized Low-Density Lipoprotein Accumulation Suppresses Glycolysis and Attenuates the Macrophage Inflammatory Response by Diverting Transcription from the HIF-1α to the Nrf2 Pathway

Lipid accumulation in macrophages (Mφs) is a hallmark of atherosclerosis, yet how lipid accumulation affects inflammatory responses through rewiring of Mφ metabolism is poorly understood. We modeled lipid accumulation in cultured wild-type mouse thioglycolate-elicited peritoneal Mφs and bone marrow-derived Mφs with conditional (Lyz2-Cre) or complete genetic deficiency of Vhl, Hif1a, Nos2, and Nfe2l2. Transfection studies employed RAW264.7 cells. Mφs were cultured for 24 h with oxidized low-density lipoprotein (oxLDL) or cholesterol and then were stimulated with LPS. Transcriptomics revealed that oxLDL accumulation in Mφs downregulated inflammatory, hypoxia, and cholesterol metabolism pathways, whereas the antioxidant pathway, fatty acid oxidation, and ABC family proteins were upregulated. Metabolomics and extracellular metabolic flux assays showed that oxLDL accumulation suppressed LPS-induced glycolysis. Intracellular lipid accumulation in Mφs impaired LPS-induced inflammation by reducing both hypoxia-inducible factor 1-α (HIF-1α) stability and transactivation capacity; thus, the phenotype was not rescued in Vhl-/- Mφs. Intracellular lipid accumulation in Mφs also enhanced LPS-induced NF erythroid 2-related factor 2 (Nrf2)-mediated antioxidative defense that destabilizes HIF-1α, and Nrf2-deficient Mφs resisted the inhibitory effects of lipid accumulation on glycolysis and inflammatory gene expression. Furthermore, oxLDL shifted NADPH consumption from HIF-1α- to Nrf2-regulated apoenzymes. Thus, we postulate that repurposing NADPH consumption from HIF-1α to Nrf2 transcriptional pathways is critical in modulating inflammatory responses in Mφs with accumulated intracellular lipid. The relevance of our in vitro models was established by comparative transcriptomic analyses, which revealed that Mφs cultured with oxLDL and stimulated with LPS shared similar inflammatory and metabolic profiles with foamy Mφs derived from the atherosclerotic mouse and human aorta.

Decreased Nrf2 protein level and low sperm quality in intractable spermatocystitis

ABSTRACT

To investigate the molecular etiology of low sperm quality in patients with intractable spermatocystitis, spermatozoa samples from patients with persistent hematospermia undergoing transurethral seminal vesiculoscopy and healthy volunteers were utilized. Spermatozoa samples were collected from the seminal vesicles through transurethral seminal vesiculoscopy or by masturbation ejaculation. Sperm quality was analyzed by a WLJY-9000 color semen analysis system. Measurement of tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) in the seminal plasma was performed using enzyme-linked immunosorbent assay (ELISA). Measurement of H2O2 in the seminal plasma was performed with a hydrogen peroxide kit. The protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and phosphorylated-Nrf2 (p-Nrf2) were measured by western blot analysis and immunofluorescence assays. Low sperm quality parameters and increased levels of inflammatory cytokines (TNFα, IL-6, and H2O2) in the seminal plasma were detected among the semen samples from the patients with persistent hematospermia. Nrf2 and p-Nrf2 were strongly expressed in the nucleus and periphery of human sperm cells, according to the results of the immunofluorescence assays. The protein levels of Nrf2 and p-Nrf2 were significantly lower in the spermatozoa samples from patients with persistent hematospermia than in those from healthy volunteers with normal sperm motility. The results suggested that Nrf2 signaling might play a role in the low sperm quality of patients with intractable spermatocystitis.

Role of HNF4alpha-cMyc interaction in liver regeneration and recovery after acetaminophen-induced acute liver injury

BACKGROUND AND AIMS

Overdose of acetaminophen (APAP) is the major cause of acute liver failure in the western world. We report a novel signaling interaction between hepatocyte nuclear factor 4 alpha (HNF4α) cMyc and nuclear factor erythroid 2-related factor 2 (Nrf2) during liver injury and regeneration after APAP overdose.

APPROACH AND RESULTS

APAP-induced liver injury and regeneration were studied in male C57BL/6J (WT) mice, hepatocyte-specific HNF4α knockout mice (HNF4α-KO), and HNF4α-cMyc double knockout mice (DKO). C57BL/6J mice treated with 300 mg/kg maintained nuclear HNF4α expression and exhibited liver regeneration, resulting in recovery. However, treatment with 600-mg/kg APAP, where liver regeneration was inhibited and recovery was delayed, showed a rapid decline in HNF4α expression. HNF4α-KO mice developed significantly higher liver injury due to delayed glutathione recovery after APAP overdose. HNF4α-KO mice also exhibited significant induction of cMyc, and the deletion of cMyc in HNF4α-KO mice (DKO mice) reduced the APAP-induced liver injury. The DKO mice had significantly faster glutathione replenishment due to rapid induction in Gclc and Gclm genes. Coimmunoprecipitation and ChIP analyses revealed that HNF4α interacts with Nrf2 and affects its DNA binding. Furthermore, DKO mice showed significantly faster initiation of cell proliferation resulting in rapid liver regeneration and recovery.

CONCLUSIONS

These data show that HNF4α interacts with Nrf2 and promotes glutathione replenishment aiding in recovery from APAP-induced liver injury, a process inhibited by cMyc. These studies indicate that maintaining the HNF4α function is critical for regeneration and recovery after APAP overdose.

Boosting NAD preferentially blunts Th17 inflammation via arginine biosynthesis and redox control in healthy and psoriasis subjects

To evaluate whether nicotinamide adenine dinucleotide-positive (NAD+) boosting modulates adaptive immunity, primary CD4+ T cells from healthy control and psoriasis subjects were exposed to vehicle or nicotinamide riboside (NR) supplementation. NR blunts interferon γ (IFNγ) and interleukin (IL)-17 secretion with greater effects on T helper (Th) 17 polarization. RNA sequencing (RNA-seq) analysis implicates NR blunting of sequestosome 1 (sqstm1/p62)-coupled oxidative stress. NR administration increases sqstm1 and reduces reactive oxygen species (ROS) levels. Furthermore, NR activates nuclear factor erythroid 2-related factor 2 (Nrf2), and genetic knockdown of nrf2 and the Nrf2-dependent gene, sqstm1, diminishes NR amelioratory effects. Metabolomics analysis identifies that NAD+ boosting increases arginine and fumarate biosynthesis, and genetic knockdown of argininosuccinate lyase ameliorates NR effects on IL-17 production. Hence NR via amino acid metabolites orchestrates Nrf2 activation, augments CD4+ T cell antioxidant defenses, and attenuates Th17 responsiveness. Oral NR supplementation in healthy volunteers similarly increases serum arginine, sqstm1, and antioxidant enzyme gene expression and blunts Th17 immune responsiveness, supporting evaluation of NAD+ boosting in CD4+ T cell-linked inflammation.

lncRNA HOTAIR promotes ROS generation and NLRP3 inflammasome activation by inhibiting Nrf2 in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a microvascular complication associated with damage to the retina due to inflammation induced by high glucose. Activation of the NLRP3 inflammasome plays a critical role in DR and its prevention is beneficial to patients. However, the regulation of long non-coding RNA (lncRNA) in NLRP3 inflammasome activation of DR is incompletely understood. So, this study aimed to uncover the functional and regulatory mechanism of the lncRNA HOTAIR in NLRP3 inflammasome activation in Dr.

METHODS

The vitreous humor was collected from the patients and detected the inflammatory and oxidative stress makers. Human retinal endothelial cells (HRECs) were cultured and stimulated in low D-glucose (5 mmol/L) or high D-glucose (20 mmol/L). Additionally, HRECs were knocked down HOTAIR with a si-RNA. Then, the NLRP3 inflammasome activation was analyzed by western blotting and pyroptosis cell imaging. The ROS was measured by specific probe. The activation of Nrf2 measured by Immunofluorescent staining. The interaction between HOTAIR and Nrf2 was evaluated by co-immunoprecipitation and RNA immunoprecipitation.

RESULTS

The expression of HOTAIR was significantly increased in the vitreous of patients with DR and in HRECs stimulated with high glucose. Furthermore, HOTAIR knockdown relieved NLRP3 inflammasome activation. More specifically, HOTAIR knockdown suppressed the expression of NLRP3, pro-caspase-1, and pro-IL-1β, as well as IL-1β maturation and pyroptosis. HOTAIR knockdown also interfered with the ROS generation induced by high glucose. Moreover, HOTAIR promoted the interaction between Nrf2 and Keap1 by binding and inactivating Nrf2.

CONCLUSION

The lncRNA HOTAIR promotes NLRP3 inflammasome activation and ROS generation by inhibiting Nrf2 in Dr.

Antioxidant, Pro-Survival and Pro-Regenerative Effects of Conditioned Medium from Wharton's Jelly Mesenchymal Stem Cells on Developing Zebrafish Embryos

Conditioned media harvested from stem cell culturing have the potential to be innovative therapeutic tools against various diseases, due to their high content of growth, trophic and protective factors. The evaluation in vivo of the effects and biosafety of these products is essential, and zebrafish provides an ideal platform for high-throughput toxicological analysis, concurrently allowing the minimization of the use of mammalian models without losing reliability. In this study, we assessed the biological effects elicited by the exposure of zebrafish embryos to a conditioned medium derived from Wharton's jelly mesenchymal stem cells. By a multiparametric investigation combining molecular, embryological, behavioural and in vivo imaging techniques, we found that exposure to a conditioned medium at a non-toxic/non-lethal dosage triggers antioxidant, anti-apoptotic and pro-regenerative effects, by upregulation of a set of genes involved in antioxidant defence (nrf2, brg1, sirt1, sirt6, foxO3a, sod2 and cat), glycolysis (ldha) and cell survival (bcl2l1, mcl1a and bim), coupled to downregulation of pro-apoptotic markers (baxa, caspase-3a and caspase-8). To our knowledge, this is the first study comprehensively addressing the effects of a conditioned medium on a whole organism from a developmental, molecular and behavioural perspective, and we are fairly confident that it will pave the way for future therapeutic application.

Exploring cell competition for the prevention and therapy of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is characterized by the development of cancer in the esophageal squamous epithelium through a step-by-step accumulation of genetic, epigenetic, and histopathological alterations. Recent studies have demonstrated that cancer-associated gene mutations exist in histologically normal or precancerous clones of the human esophageal epithelium. However, only a small proportion of such mutant clones will develop ESCC, and most ESCC patients develop only one cancer. This suggests that most of these mutant clones are kept in a histologically normal state by neighboring cells with higher competitive fitness. When some of the mutant cells evade cell competition, they become "super-competitors" and develop into clinical cancer. It is known that human ESCC is composed of a heterogeneous population of cancer cells that interact with and influence their environment and neighbors. During cancer therapy, these cancer cells not only respond to therapeutic agents but also compete with each other. Therefore, competition between ESCC cells within the same ESCC tumor is a constantly dynamic process. However, it remains challenging to fine-tune the competitive fitness of various clones for therapeutic benefits. In this review, we will explore the role of cell competition in carcinogenesis, cancer prevention, and therapy, using NRF2, NOTCH pathway, and TP53 as examples. We believe that cell competition is a research area with promising targets for clinical translation. Manipulating cell competition may help improve the prevention and therapy of ESCC.

Methyl and Fluorine Effects in Novel Orally Bioavailable Keap1-Nrf2 PPI Inhibitor

Oxidative stress is one of the causes of progression of chronic kidney disease (CKD). Activation of the antioxidant protein regulator Nrf2 by inhibition of the Keap1-Nrf2 protein-protein interaction (PPI) is of interest as a potential treatment for CKD. We report the identification of the novel and weak PPI inhibitor 7 with good physical properties by a high throughput screening (HTS) campaign, followed by structural and computational analysis. The installation of only methyl and fluorine groups successfully provided the lead compound 25, which showed more than 400-fold stronger activity. Furthermore, these dramatic substituent effects can be explained by the analysis of using isothermal titration calorimetry (ITC). Thus, the resulting 25, which exhibited high oral absorption and durability, would be a CKD therapeutic agent because of the dose-dependent manner for up-regulation of the antioxidant protein heme oxigenase-1 (HO-1) in rat kidneys.

Matrine-induced nephrotoxicity via GSK-3β/nrf2-mediated mitochondria-dependent apoptosis

INTRODUCTION

Matrine (MT), an ingredient extracted from the Chinese herb Sophora flavescens, can result in nephrotoxicity because of long-term exposure. However, the underlying mechanism by which MT leads to kidney injury remains unclear. This study aimed to investigate the roles of oxidative stress and mitochondria in MT-induced kidney toxicity both in vitro and in vivo.

METHODS

Mice were exposed to MT for 20 days, and NRK-52E cells were exposed to MT with or without LiCl (a GSK-3β inhibitor), tert-Butylhydroquinone (t-BHQ, an Nrf2 activator), or small interfering RNA.

RESULTS

The results showed that MT caused nephrotoxicity accompanied by an increase in reactive oxygen species (ROS) accumulation and mitochondrial dysfunction. Meanwhile, MT significantly upregulated glycogen synthase kinase-3β (GSK-3β) activity, released cytochrome c (Cyt C) and cleaved caspase-3, decreased the activity of nuclear factor-erythroid 2-related Factor 2 (Nrf2), and reduced the expression of heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO-1), which led to the inactivation of antioxidant enzymes and the activation of apoptosis. In addition, GSK-3β inhibition by LiCl or small interfering RNA pretreatment or Nrf2 activation by t-BHQ pretreatment attenuated the toxic effects of MT in NRK-52E cells.

CONCLUSIONS

Taken together, these results revealed that MT-induced apoptosis triggered kidney toxicity and that GSK-3β or Nrf2 might serve as a promising nephroprotective target for MT-induced kidney injury.

Protein Kinase B (PKB/AKT) Protects IDH-Mutated Glioma from Ferroptosis via Nrf2

PURPOSE

Mutations of the isocitrate dehydrogenase (IDH) gene are common genetic mutations in human malignancies. Increasing evidence indicates that IDH mutations play critical roles in malignant transformation and progression. However, the therapeutic options for IDH-mutated cancers remain limited. In this study, the investigation of patient cohorts revealed that the PI3K/protein kinase B (AKT) signaling pathways were enhanced in IDH-mutated cancer cells.

EXPERIMENTAL DESIGN

In this study, we investigated the gene expression profile in IDH-mutated cells using RNA sequencing after the depletion of AKT. Gene set enrichment analysis (GSEA) and pathway enrichment analysis were used to discover altered molecular pathways due to AKT depletion. We further investigated the therapeutic effect of the AKT inhibitor, ipatasertib (Ipa), combined with temozolomide (TMZ) in cell lines and preclinical animal models.

RESULTS

GSEA and pathway enrichment analysis indicated that the PI3K/AKT pathway significantly correlated with Nrf2-guided gene expression and ferroptosis-related pathways. Mechanistically, AKT suppresses the activity of GSK3β and stabilizes Nrf2. Moreover, inhibition of AKT activity with Ipa synergizes with the genotoxic agent TMZ, leading to overwhelming ferroptotic cell death in IDH-mutated cancer cells. The preclinical animal model confirmed that combining Ipa and TMZ treatment prolonged survival.

CONCLUSIONS

Our findings highlighted AKT/Nrf2 pathways as a potential synthetic lethality target for IDH-mutated cancers.

Melatonin protects human nucleus pulposus cells from pyroptosis by regulating Nrf2 via melatonin membrane receptors

Aims

This study was performed to explore the effect of melatonin on pyroptosis in nucleus pulposus cells (NPCs) and the underlying mechanism of that effect.

Methods

This experiment included three patients diagnosed with lumbar disc herniation who failed conservative treatment. Nucleus pulposus tissue was isolated from these patients when they underwent surgical intervention, and primary NPCs were isolated and cultured. Western blotting, reverse transcription polymerase chain reaction, fluorescence staining, and other methods were used to detect changes in related signalling pathways and the ability of cells to resist pyroptosis.

Results

Western blot analysis confirmed the expression of cleaved CASP-1 and melatonin receptor (MT-1A-R) in NPCs. The cultured NPCs were identified by detecting the expression of CD24, collagen type II, and aggrecan. After treatment with hydrogen peroxide, the pyroptosis-related proteins NLR family pyrin domain containing 3 (NLRP3), cleaved CASP-1, N-terminal fragment of gasdermin D (GSDMD-N), interleukin (IL)-18, and IL-1β in NPCs were upregulated, and the number of propidium iodide (PI)-positive cells was also increased, which was able to be alleviated by pretreatment with melatonin. The protective effect of melatonin on pyroptosis was blunted by both the melatonin receptor antagonist luzindole and the nuclear factor erythroid 2–related factor 2 (Nrf2) inhibitor ML385. In addition, the expression of the transcription factor Nrf2 was up- or downregulated when the melatonin receptor was activated or blocked by melatonin or luzindole, respectively.

Conclusion

Melatonin protects NPCs against reactive oxygen species-induced pyroptosis by upregulating the transcription factor Nrf2 via melatonin receptors.

Cite this article: Bone Joint Res 2023;12(3):202–211.

NUCLEAR FACTOR-ERYTHROID-2-RELATED FACTOR REGULATES SYSTEMIC AND PULMONARY BARRIER FUNCTION AND IMMUNE PROGRAMMING AFTER BURN AND INHALATION INJURY

ABSTRACT

Major burn injury is associated with systemic hyperinflammatory and oxidative stresses that encompass the wound, vascular, and pulmonary systems that contribute to complications and poor outcomes. These stresses are exacerbated if there is a combined burn and inhalation (B+I) injury, which leads to increases in morbidity and mortality. Nuclear factor-erythroid-2-related factor (NRF2) is a transcription factor that functions to maintain homeostasis during stress, in part by modulating inflammation and oxidative injury. We hypothesized that the NRF2-mediated homeostasis after burn alone and combined B-I injury is insufficient, but that pharmacological activation of the NRF2 pathway has the potential to reduce/reverse acute hyper inflammatory responses. We found that, after burn and B+I injury, Nrf2 -/- mice have higher mortality and exhibit greater pulmonary edema, vascular permeability, and exacerbated pulmonary and systemic proinflammatory responses compared with injured wild-type (WT) controls. Transcriptome analysis of lung tissue revealed specific Nrf2 -dependent dysregulated immune pathways after injury. In WT mice, we observed that B+I injury induces cytosolic, but not nuclear, accumulation of NRF2 protein in the lung microenvironment compared with sham-injured controls. Bardoxolone methyl (CDDO-Me)-containing microparticles (CDDO-MPs) were developed that allow for dilution in saline and stable release of CDDO-Me. When delivered intraperitoneally into mice 1 hour after B+I injury, CDDO-MPs significantly reduced mortality and cytokine dysfunction compared with untreated B-I animals. These data implicate the role of NRF2 regulation of pulmonary and systemic immune dysfunction after burn and B+I injury, and also a deficiency in controlling immune dysregulation. Selectively activating the NRF2 pathway may improve clinical outcomes in burn and B+I patients.

Cell-Permeable PROTAC Degraders against KEAP1 Efficiently Suppress Hepatic Stellate Cell Activation through the Antioxidant and Anti-Inflammatory Pathway

Accumulating evidence indicates that oxidative stress and inflammation are involved in the physiopathology of liver fibrogenesis. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor, which regulates the expression of redox regulators to establish cellular redox homeostasis. The Nrf2 modulator can serve as a primary cellular defense against the cytotoxic effects of oxidative stress. We designed a chimeric Keap1-Keap1 peptide (KKP1) based on the proteolysis-targeting chimera technology. The KKP1 peptide not only can efficiently penetrate into the rat hepatic stellate cell line (HSC-T6) cells but also can induce Keap1 protein degradation by the ubiquitination-proteasome degradation pathway, which releases Nrf2 and promotes the transcriptional activity of the Nrf2/antioxidant response element pathway. It then activates the protein expression of the downstream antioxidant factors, the glutamate-cysteine ligase catalytic subunit and heme oxygenase-1 (HO-1). Finally, Keap1 protein degradation inhibits the nuclear factor-kappaB inflammatory signal pathway, the downstream inflammatory factor tumor necrosis factor alpha, and the interleukin-1beta protein expression and further inhibits the expression of the fibrosis biomarker gene. The current research suggests that our designed KKP1 may provide a new avenue for the future treatment of liver fibrosis.

Modeling Preclinical Cancer Studies under Physioxia to Enhance Clinical Translation

Oxygen (O2) plays a key role in cellular homeostasis. O2 levels are tightly regulated in vivo such that each tissue receives an optimal amount to maintain physiologic status. Physiologic O2 levels in various organs range between 2% and 9% in vivo, with the highest levels of 9% in the kidneys and the lowest of 0.5% in parts of the brain. This physiologic range of O2 tensions is disrupted in pathologic conditions such as cancer, where it can reach as low as 0.5%. Regardless of the state, O2 tension in vivo is maintained at significantly lower levels than ambient O2, which is approximately 21%. Yet, routine in vitro cellular manipulations are carried out in ambient air, regardless of whether or not they are eventually transferred to hypoxic conditions for subsequent studies. Even brief exposure of hematopoietic stem cells to ambient air can cause detrimental effects through a mechanism termed extraphysiologic oxygen shock/stress (EPHOSS), leading to reduced engraftment capabilities. Here, we provide an overview of the effects of ambient air exposure on stem and non-stem cell subtypes, with a focus on recent findings that reveal the impact of EPHOSS on cancer cells.

Salidroside reduces neuropathology in Alzheimer’s disease models by targeting NRF2/SIRT3 pathway

Background

Neurite dystrophy is a pathologic hallmark of Alzheimer’s disease (AD). However, drug discovery targeting neurite protection in AD remains largely unexplored.

Methods

Aβ-induced neurite and mitochondrial damage assays were used to evaluate Aβ toxicity and the neuroprotective efficacy of a natural compound salidroside (SAL). The 5×FAD transgenic mouse model of AD was used to study the neuroprotective function of SAL. To verify the direct target of SAL, we used surface plasmon resonance and cellular thermal shift assays to analyze the drug-protein interaction.

Results

SAL ameliorates Aβ-mediated neurite damage in cell culture. We further reveal that SAL represses mitochondrial damage in neurites by promoting mitophagy and maintaining mitochondrial homeostasis, dependent on an NAD-dependent deacetylase SIRT3. In AD mice, SAL protects neurite morphology, mitigates Aβ pathology, and improves cognitive function, which are all SIRT3-dependent. Notably, SAL directly binds to transcription factor NRF2, inhibits its degradation by blocking its interaction with KEAP1 ubiquitin ligase, and then advances NRF2-mediated SIRT3 transcription.

Conclusions

Overall, we demonstrate that SAL, a potential anti-aging drug candidate, attenuates AD pathology by targeting NRF2/SIRT3 pathway for mitochondrial and neurite protection. Drug discovery strategies focusing on SAL may thus provide promising therapeutics for AD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00918-z.

Naringin regulates mitochondrial dynamics to protect against acetaminophen-induced hepatotoxicity by activating the AMPK/Nrf2 signaling pathway in vitro

Naringin (Nar) has been reported to exert potential hepatoprotective effects against acetaminophen (APAP)-induced injury. Mitochondrial dysfunction plays an important role in APAP-induced liver injury. However, the protective mechanism of Nar against mitochondrial damage has not been elucidated. Therefore, the aim of this study was to investigate the hepatoprotective effects of Nar against APAP and the possible mechanisms of actions. Primary rat hepatocytes and HepG2 cells were utilized to establish an in vitro model of APAP-induced hepatotoxicity. The effect of APAP and Nar on cell viability was evaluated by a CCK8 assay and detection of the concentrations of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase. The cellular concentrations of biomarkers of oxidative stress were measured by ELISA. The mRNA expression levels of APAP-related phase II enzymes were determined by real-time PCR. The protein levels of Nrf2, phospho (p)-AMPK/AMPK, and biomarkers of mitochondrial dynamics were determined by western blot analysis. The mitochondrial membrane potential (MMP) was measured by high-content analysis and confocal microscopy. JC-1 staining was performed to evaluate mitochondrial depolarization. Nar pretreatment notably prevented the marked APAP-induced hepatocyte injury, increases in oxidative stress marker expression, reductions in the expression of phase II enzymes, significant loss of MMP, mitochondrial depolarization, and mitochondrial fission in vitro. In conclusion, Nar alleviated APAP-induced hepatocyte and mitochondrial injury by activating the AMPK/Nrf2 pathway to reduce oxidative stress in vitro. Applying Nar for the treatment of APAP-induced liver injury might be promising.

NRF2 mediates melanoma addiction to GCDH by modulating apoptotic signalling

Tumour dependency on specific metabolic signals has been demonstrated and often guided numerous therapeutic approaches. We identify melanoma addiction to the mitochondrial protein glutaryl-CoA dehydrogenase (GCDH), which functions in lysine metabolism and controls protein glutarylation. GCDH knockdown induced cell death programmes in melanoma cells, an activity blocked by inhibition of the upstream lysine catabolism enzyme DHTKD1. The transcription factor NRF2 mediates GCDH-dependent melanoma cell death programmes. Mechanistically, GCDH knockdown induces NRF2 glutarylation, increasing its stability and DNA binding activity, with a concomitant transcriptional upregulation of ATF4, ATF3, DDIT3 and CHAC1, resulting in cell death. In vivo, inducible inactivation of GCDH effectively inhibited melanoma tumour growth. Correspondingly, reduced GCDH expression correlated with improved survival of patients with melanoma. These findings identify melanoma cell addiction to GCDH, limiting apoptotic signalling by controlling NRF2 glutarylation. Inhibiting the GCDH pathway could thus represent a therapeutic approach to treat melanoma.

Melatonin attenuates polystyrene microplastics induced motor neurodevelopmental defect in zebrafish (Danio rerio) by activating nrf2 - isl2a Axis

Microplastics, a new type of ecological pollutant, have now become a major environmental concern worldwide. Polystyrene microplastics (PS), one of the most abundant form of microplastics, cause deleterious effects across species. Melatonin (MT), which is secreted by pineal gland, exhibits protective role against pollutant-induced damage. However, whether MT could ameliorate PS-induced neurodevelopmental toxicity remain unclear. In our study, zebrafish embryos were treated with PS (0.5, 25 mg/L) in the presence or absence of MT (1 μM) from 4 h post-fertilization (hpf) to 144 hpf. Locomotion behavior, oxidative stress, apoptosis, proliferation and development of caudal primary (Cap) motoneuron axon were analyzed. Gene expression was determined by qRT-PCR or whole-mount in situ hybridization. Results showed that PS exposure significantly reduced swimming speed of zebrafish larvae and induced excessive reactive oxygen species (ROS), apoptosis and aberrant proliferation. In addition, PS treatment markedly shortened the length of Cap motoneuron axons and decreased expression of neurodevelopment related genes. While, MT administration considerably rescued the neurodevelopmental toxicity of PS. Mechanistically, MT activated nrf2 (nuclear factor-E2-related factor 2) - isl2a (ISL LIM homeobox 2a) axis to antagonize the side effects of PS. In all, our findings suggest that PS exposure during early life lead to aberrant neurodevelopment of zebrafish, and MT might be a therapeutic option for protecting such disorder.

Cold Exposure Induces Intestinal Barrier Damage and Endoplasmic Reticulum Stress in the Colon via the SIRT1/Nrf2 Signaling Pathway

Ambient air temperature is a key factor affecting human health. Long-term exposure to a cold environment can cause various diseases, while the impact on the intestine, the organ which has the largest contact area with the external environment, cannot be ignored. In this study, we investigated the effect of chronic cold exposure on the colon and its preliminary mechanism of action. Mice were exposed to 4°C for 3 hours a day for 10 days. We found that cold exposure damaged the morphology and structure of the colon, destroyed the tight junctions of the colonic epithelial tissue, and promoted inflammation of the colon. At the same time, cold exposure also activated the unfolded protein response (UPR) in the colon and promoted apoptosis in intestinal epithelial cells. Chronic cold exposure induced oxidative stress in vivo, but also significantly enhanced the response of the Nrf2 pathway that promotes an anti-oxidant effect. Furthermore, we demonstrated that chronic cold exposure promoted p65 acetylation to aggravate the inflammatory response by inhibiting SIRT1. Similar results were observed following SIRT1 knock-down by shRNA in Caco-2 cells treated with Thapsigargin (Tg). Knock-down of SIRT1 promoted nuclear localization of Nrf2, and increased the level of Nrf2 acetylation. Taken together, our study indicates that cold exposure may aggravate endoplasmic reticulum stress and damage epithelial tight junctions in the colon by inhibiting SIRT1, which promotes nuclear localization of Nrf2 and induces an anti-oxidant response to maintain intestinal homeostasis. These findings suggest that SIRT1 is a potential target for regulating intestinal health under cold exposure conditions.

Ellagic acid attenuates interleukin-1β-induced oxidative stress and exerts protective effects on chondrocytes through the Kelch-like ECH-associated protein 1 (Keap1)/ Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway

Osteoarthritis (OA) is the most prevalent type of degenerative joint disease, and its pathological progression is highly associated with oxidative stress. Natural antioxidants can attenuate oxidative stress and chondrocyte injury, suggesting that antioxidants have potential applications in the management of OA. Ellagic acid (EA), a natural polyphenol derived from fruits or nuts, exerts antioxidant and anti-inflammatory effects in diseases related to oxidative stress. Herein, we investigated the effects of EA on interleukin-1β (IL-1β)-induced oxidative stress and degeneration in C28/I2 human chondrocytes. EA efficiently suppressed IL-1β-induced oxidative stress and ameliorated oxidative stress-induced dysfunction of chondrocytes, as indicated by the promotion of cartilage matrix secretion. Moreover, EA remarkably suppressed cell apoptosis and senescence, and reduced the expression of proinflammatory factors and metalloproteinases, suggesting that EA could alleviate chondrocyte injury under oxidative stress. Mechanistically, EA upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) as well as its downstream targets NADPH quinone oxidoreductase 1 and heme oxygenase-1. ML385, a specific Keap1/Nrf2 pathway inhibitor, blocked the antioxidant and chondroprotective effects of EA. Our findings demonstrated that EA could attenuate oxidative stress and exert protective effects on chondrocytes by upregulating the Keap1/Nrf2 signaling pathway.

Nuclear Factor Erythroid 2-Related Factor 2 Activation and Burn-Induced Cardiac Dysfunction

BACKGROUND

Our previous studies have found that burn injury induces cardiac dysfunction through interruption of the antioxidant-response element (ARE) pathway in cardiac mitochondria. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator that activates many antioxidant enzymes. Oltipraz (Olti) is a Nrf2 activator and a well-known inducer of NQO1 along with other enzymes that comprise the Nrf2-associated antioxidants. We propose that Nrf2 activation will induce the ARE pathway, leading to abrogation of burn-induced cardiac dysfunction.

STUDY DESIGN

In this study, we investigated the effect of Nrf2-deficiency in mice on burn-induced cardiac dysfunction. Wild-type (WT) and Nrf2-deficient mice received 30% total body surface area burn injury and were treated with or without Olti and then harvested at 3 hours and 24 hours post burn (3 hpb and 24 hpb).

RESULTS

As expected, Nrf2-deficient mice exhibited exacerbated cardiac dysfunction after burn injury, as measured by Vevo 2100 echocardiography. Electron microscopy showed that Nrf2 depletion worsened burn injury-induced cardiac mitochondrial damage. In addition, Nrf2 depletion increased cardiac mitochondrial dysfunction and myocardial fibrosis after burn injury. Treatment with Olti ameliorated the heart dysfunction in burned Nrf2-/+ mice, improved cardiac mitochondrial structure and oxidative phosphorylation, as well as decreased cardiac fibrosis. These results suggest that Nrf2 and its downstream targets modulate cardiac function after burn injury.

CONCLUSIONS

In summary, Nrf2 depletion worsens cardiac dysfunction after burn injury. Nrf2 activation, with a drug such as Olti, offers a promising therapeutic strategy for abrogating burn-induced cardiac dysfunction.

Renoprotective effect of N-acetylcystein and vitamin E in bisphenol A-induced rat nephrotoxicity; Modulators of Nrf2/ NF-κB and ROS signaling pathway

BACKGROUND AND AIM OF THE WORK

Bisphenol A (BPA) is a chemical product that is widely used as a plastic precursor. It acts directly on the kidney mitochondria, causing renal dysfunction. N-acetylcysteine is effective in protecting the kidneys from chemical-induced damage. Vitamin E is an antioxidant that protects cells from the damaging effects of free radicals. The aim of this study is to further evaluate and compare NAC and vitamin E to oppose the nephrotoxicity caused by BPA.

RESEARCH DESIGN AND METHODS

Forty-two adult male rats were divided into 7 groups:  control, BPA, NAC, vitamin E, BPA plus NAC, BPA plus vitamin E, and combined BPA, NAC and vitamin E. BPA, NAC, vitamin E were given orally at doses of 50 mg/kg, 200 mg/kg, and 1000 mg/kg respectively, for 5 weeks.

RESULTS

NAC and vitamin E groups showed improved kidney function tests and alleviated BPA-induced oxidative stress; increased GSH and decreased MDA, NO and iNOS levels. NAC and vitamin E significantly attenuated inflammation; decreased NF-κB and increased IL-4, and Nrf2, in addition there was alleviation of renal histopathology. To some extent, vitamin E administration showed significant improvement. Moreover, combined NAC and vitamin E treatment showed more significance than either NAC or vitamin E separate groups.

CONCLUSIONS

This study determined the substantial protective effects of NAC and/or vitamin E in BPA-induced nephrotoxicity through modulation of Nrf2 with subsequent improvement of oxidative stress and inflammation. The alleviation was more significant in combined NAC and vitamin E treatment mainly through their synergistic effect on Nrf2.

Yiqi Huoxue Recipe inhibits cardiomyocyte apoptosis caused by heart failure through Keap1/Nrf2/HIF-1α signaling pathway

Yiqi Huoxue Recipe (YHR) is commonly used in China to treat diseases such as heart failure (HF). It has been reported that YHR can treat HF and has a certain protective effect on myocardial cell damage. The purpose of this study is to determine the cardioprotective effects of YHR on HF-induced apoptosis and to clarify its mechanism of action. Oxygen glucose deprivation/recovery (OGD/R) induces H9C2 cell apoptosis model. Ligation of the left anterior descending artery (LAD) coronary artery can induce an animal model of HF. We found that YHR protected H9C2 cells from OGD/R-induced apoptosis, reduced the level of reactive oxygen species (ROS) in H9C2 cells, and increased the mitochondrial membrane potential in H9C2 cells. The results of in vivo animal experiments showed that in the HF model, YHR could reduce infarct area of heart tissue and cardiomyocyte apoptosis rate. YHR regulated the expression of key apoptotic molecules, including increasing the ratio of Bcl-2 and Bax, and reducing the expression of Kelch-like ECH-associated protein 1 (Keap1) and caspase-3. Interestingly, YHR also regulates the expression of NF-E2-related factor 2 (Nrf2) in the nucleus. In summary, YHR may provide cardioprotective effects in heart failure through inhibiting the Keap1/Nrf2/HIF-1α apoptosis pathway.

Neuroprotective mechanisms of red clover and soy isoflavones in Parkinson's disease models

Parkinson's disease (PD) is a neurodegenerative disorder characterized by nigrostriatal degeneration and the spreading of aggregated forms of the presynaptic protein α-synuclein (aSyn) throughout the brain. PD patients are currently only treated with symptomatic therapies, and strategies to slow or stop the progressive neurodegeneration underlying the disease's motor and cognitive symptoms are greatly needed. The time between the first neurobiochemical alterations and the initial presentation of symptoms is thought to span several years, and early neuroprotective dietary interventions could delay the disease onset or slow PD progression. In this study, we characterized the neuroprotective effects of isoflavones, a class of dietary polyphenols found in soy products and in the medicinal plant red clover (Trifolium pratense). We found that isoflavone-rich extracts and individual isoflavones rescued the loss of dopaminergic neurons and the shortening of neurites in primary mesencephalic cultures exposed to two PD-related insults, the environmental toxin rotenone and an adenovirus encoding the A53T aSyn mutant. The extracts and individual isoflavones also activated the Nrf2-mediated antioxidant response in astrocytes via a mechanism involving inhibition of the ubiquitin-proteasome system, and they alleviated deficits in mitochondrial respiration. Furthermore, an isoflavone-enriched soy extract reduced motor dysfunction exhibited by rats lesioned with the PD-related neurotoxin 6-OHDA. These findings suggest that plant-derived isoflavones could serve as dietary supplements to delay PD onset in at-risk individuals and mitigate neurodegeneration in the brains of patients.

Glycyrrhizic acid alleviates the meconium-induced acute lung injury in neonatal rats by inhibiting oxidative stress through mediating the Keap1/Nrf2/HO-1 signal pathway

Meconium aspiration syndrome (MAS) is a disease closely related to inflammation and oxidative stress. Glycyrrhizic acid (GA) is a triterpenoid isolated from licorice with multiple bioprotective properties. In the present study, impacts of GA against MAS rats, as well as the potential mechanism, will be investigated. MAS model was established on newborn rats, followed by the treatment of 12.5, 25, and 50 mg/kg GA. The wet/dry weight ratio of lung tissues was calculated. The production of IL-6, IL-1β, TNF-α, malonaldehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) was measured using ELISA assay. HE staining was used to evaluate the pathological state of lung tissues and TUNEL assay was used to detect the apoptotic state. The protein expression of Nrf2, Keap1, HO-1, Bcl-2, Bax, and cleaved-Caspase3 was measured by Western blotting assay. The elevated W/D ratio, release of inflammatory factors, lung injury score, and apoptotic index, as well as the activated oxidative stress and suppressed Keap1/Nrf2/HO-1 pathway, in MAS rats were significantly alleviated by GA. After introducing the inhibitor of Nrf2, ML385, the protective property of GA on the pathological state, apoptotic index, and oxidative stress in MAS rats was pronouncedly abolished. Taken together, glycyrrhizin alleviated GAH in rats by suppressing Keap1/Nrf2/HO-1 signaling mediated oxidative stress.

Skeletal Muscle Nrf2 Contributes to Exercise-Evoked Systemic Antioxidant Defense Via Extracellular Vesicular Communication

This review explores the hypothesis that the repetitive contraction-relaxation that occurs during chronic exercise activates skeletal myocyte nuclear factor erythroid-derived 2-like 2 (Nrf2) to upregulate antioxidant enzymes. These proteins are secreted into the circulation within extracellular vesicles and taken up by remote cells, thus providing remote organs with cytoprotection against subsequent oxidative stress.

Dimethyl fumarate protects the aged brain following chronic cerebral hypoperfusion-related ischemia in rats in Nrf2-dependent manner

It has been stated that chronic cerebral hypoperfusion (CCH) markedly prompts neuronal damage and affects cognition. Dimethyl fumarate (DMF), a nuclear erythroid 2-related factor 2 (Nrf2) activator, represents a class of molecules exhibiting neuroprotection. We explored the effect of DMF on CCH using a model of permanent left common carotid occlusion. The left common carotid artery was occluded and then DMF (100mg.kg^-1) was orally administrated three times per week for four consecutive weeks. Behavioral rests, PET imaging and Hematoxylin and Eosin staining, were examined and also, the hippocampal level of inflammatory, Nrf2 antioxidant, neuronal plasticity and apoptotic factors were determined using Western blot analysis and related ELISA kits. The neurological deficit scores were significantly reduced in the treatment group compared with the CCH group (P<0.001). DMF decreased the novel object recognition index (NOR) compared with the CCH group, while CCH + DMF increased the NOR compared with the CCH group (P<0.001). CCH + DMF reduces the ratio of Bax/Bcl2 and capase-3 activity in comparison to the CCH group (P<0.001). Treatment with DMF increased Nrf2, NAD(P)H dehydrogenase-1 and Heme oxygenase-1 and decreased Tumor necrosis factor α and Nuclear factor-κB density compared with the CCH group (P<0.001). A significant increase in brain-derived neurotrophic factor and c-fos was found in DMF-treated rats compared with the CCH group (P<0.001). Also, retinoic acid inhibits Nrf2 activation via DMF and increases inflammatory factors in hypoperfused rats' hippocampus compared with the CCH group (P<0.001). Long-term DMF treatment induces the Nrf2 pathway and has beneficial effects on memory and motility in CCH.

Exercise and Stevia Rebaudiana (R) Extracts Attenuate Diabetic Cardiomyopathy in Type 2 Diabetic Rats: Possible Underlying Mechanisms

BACKGROUND AND AIMS

In the current work, we studied the effects of exercise and stevia rebaudiana (R) extracts on diabetic cardiomyopathy (DCM) in type 2 diabetic rats and their possible underlying mechanisms.

METHODS

Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group, b) DM group, type 2 diabetic rats received 2 ml oral saline daily for 4 weeks, c) DM+ Exercise, type 2 diabetic rats were treated with exercise for 4 weeks and d) DM+ stevia R extracts: type 2 diabetic rats received methanolic stevia R extracts. By the end of the experiment, serum blood glucose, HOMA-IR, insulin and cardiac enzymes (LDH, CK-MB), cardiac histopathology, oxidative stress markers (MDA, GSH and CAT), myocardial fibrosis by Masson trichrome, the expression of p53, caspase-3, α-SMA and tyrosine hydroxylase (TH) by immunostaining in myocardial tissues were measured.

RESULTS

T2DM caused a significant increase in blood glucose, HOMA-IR index, serum CK-MB and LDH, myocardial damage and fibrosis, myocardial MDA, myocardial α-SMA, p53, caspase-3, Nrf2 and TH density with a significant decrease in serum insulin and myocardial GSH and CAT (p< 0.05). On the other hand, treatment with either exercise or stevia R extracts significantly improved all studied parameters (p< 0.05). Moreover, the effects of stevia R was more significant than exercise (p< 0.05).

CONCLUSION

Both exercise and methanolic stevia R extracts showed cardioprotective effects against DCM and Stevia R offered more cardioprotective than exercise. This cardioprotective effect of these lines of treatment might be due to attenuation of oxidative stress, apoptosis, sympathetic nerve density and fibrosis and upregulation of the antioxidant transcription factor, Nrf2.

Nattokinase Attenuates Retinal Neovascularization Via Modulation of Nrf2/HO-1 and Glial Activation

PURPOSE

Nattokinase (NK), an active ingredient extracted from traditional food Natto, has been studied for prevention and treatment of cardiovascular diseases due to various vasoprotective effects, including fibrinolytic, antihypertensive, anti-atherosclerotic, antiplatelet, and anti-inflammatory activities. Here, we reported an antineovascular effect of NK against experimental retinal neovascularization.

METHODS

The inhibitory effect of NK against retinal neovascularization was evaluated using an oxygen-induced retinopathy murine model. Expressions of Nrf2/HO-1 signaling and glial activation in the NK-treated retinae were measured. We also investigated cell proliferation and migration of human umbilical vein endothelial cells (HUVECs) after NK administration.

RESULTS

NK treatment significantly attenuated retinal neovascularization in the OIR retinae. Consistently, NK suppressed VEGF-induced cell proliferation and migration in a concentration-dependent manner in cultured vascular endothelial cells. NK ameliorated ischemic retinopathy partially via activating Nrf2/HO-1. In addition, NK orchestrated reactive gliosis and promoted microglial activation toward a reparative phenotype in ischemic retina. Treatment of NK exhibited no cell toxicity or anti-angiogenic effects in the normal retina.

CONCLUSIONS

Our results revealed the anti-angiogenic effect of NK against retinal neovascularization via modulating Nrf2/HO-1, glial activation and neuroinflammation, suggesting a promising alternative treatment strategy for retinal neovascularization.

PDSS2 Inhibits the Ferroptosis of Vascular Endothelial Cells in Atherosclerosis by Activating Nrf2

ABSTRACT

Cardiovascular disease ranks the leading cause of mortality worldwide. Prenyldiphosphate synthase subunits collectively participate in the formation and development of atherosclerosis (AS). This study aimed to investigate the role of PDSS2 in AS and its underlying mechanisms. Human coronary artery endothelial cells (HCAECs) were treated with oxidized low-density lipoprotein to establish the AS model. The gene expression levels were determined by qRT-PCR, Western blot, and ELISA. CCK-8, colony formation was applied to determine the proliferation of HCAECs. Chromatin immunoprecipitation assay and luciferase assay were applied to verify the interaction between PDSS2 and Nrf2. The results showed that the serum levels of PDSS2 and Nrf2 were decreased in patients with AS. Overexpression of PDSS2 suppressed the release of reactive oxygen species, iron content and ferroptosis of HCAECs, and promoted the proliferation of HCAECs. Moreover, PDSS2 activated antioxidant Nrf2. PDSS2 interacted with Nrf2 to alleviate the ferroptosis of HCAECs. However, knockdown of Nrf2 alleviated the effects of PDSS2 on the proliferation and ferroptosis of HCAECs. In vivo assays, overexpression of PDSS2 and Nrf2 suppressed the progression of AS. In conclusion, overexpression of PDSS2 suppressed the ferroptosis of HCAECs by promoting the activation of Nrf2 pathways. Thence PDSS2 may play a cardio-protective role in AS.

Piceatannol inhibits pyroptosis and suppresses oxLDL-induced lipid storage in macrophages by regulating miR-200a/Nrf2/GSDMD axis

As a major bioactive compound from grapes, piceatannol (PIC) has been reported to exert anti-atherosclerotic activity in various studies. Nevertheless, the mechanism underlying the effect of piceatannol against atherosclerosis (AS) is elusive. Our study identified miR-200a/Nrf2/GSDMD signaling pathway as critical mediators in the effect of piceatannol on macrophages. In the present study, we confirmed that treatment of piceatannol repressed the oxLDL-induced lipid storage in macrophages. Compared with control group, piceatannol inhibited TG storage and the activity of caspase1. It is noting that in response to oxLDL challenge, piceatannol abated the pyroptosis in RAW264.7 cells, with a decreased expression of caspase1, gasdermin D (GSDMD), IL-18, IL-1β and NLRP3. Moreover, we investigated the role of microRNA (miR)-200a/Nrf2 signaling pathway in the effect of piceatannol. The results declared that after transfection of si-miR-200a or si-Nrf2 plasmids, the effects of piceatannol on macrophages were converted, including lipid storage and pyroptosis. Importantly, si-miR-200a plasmid reduced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), indicating that miR-200a acted as an enhancer of Nrf2 in macrophages. Collectively, our findings demonstrate that piceatannol exerts anti-atherosclerotic activity on RAW264.7 cells by regulating miR-200a/Nrf2/GSDMD signaling. The present study is the first time to identify miR-200a as a candidate target in AS and declared an association between miR-200a and pyroptosis, which provides a novel therapy for the treatment of AS.

Paraoxonase 2 protects against oxygen-glucose deprivation/reoxygenation-induced neuronal injury by enhancing Nrf2 activation via GSK-3β modulation

Paraoxonase 2 (PON2) is a powerful antioxidant that mediates cell survival under oxidative stress; however, its protection neurons against cerebral ischemia-reperfusion injury-induced oxidative stress remains unclear. This study aimed to determine the precise regulating role of PON2 in neuronal survival under oxidative stress. An in vitro model of cerebral ischemia-reperfusion injury was used to assess the effect of PON2 on oxidative stress induced by oxygen-glucose deprivation/reoxygenation (OGD/R). Results showed that PON2 expression in neurons was decreased due to OGD/R exposure. A series of functional experiments revealed that upregulated PON2 improved OGD/R-impaired viability and attenuated OGD/R-induced increases in apoptosis and reactive oxygen species in neurons. Decreased PON2 expression enhanced neuronal sensitivity to OGD/R-induced injury. Overexpressed PON2 markedly enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) in the nucleus and increased the levels of Nrf2-mediated transcriptional activity. Furthermore, PON2 enhanced the Nrf2 activation by modulating glycogen synthase kinase-3β (GSK-3β). Inhibition of GSK-3β substantially abrogated the PON2 knockdown-mediated suppression of Nrf2 activity. Notably, Nrf2 inhibition partially reversed the neuroprotective effects of PON2 overexpression in OGD/R-exposed neurons. These findings indicate that PON2 alleviates OGD/R-induced apoptosis and oxidative stress in neurons by potentiating Nrf2 activation via GSK-3β modulation. This study highlights the potential neuroprotective function of PON2 against cerebral ischemia-reperfusion injury.

NRF2 Activation Promotes Aggressive Lung Cancer and Associates with Poor Clinical Outcomes

PURPOSE

Stabilization of the transcription factor NRF2 through genomic alterations in KEAP1 and NFE2L2 occurs in a quarter of patients with lung adenocarcinoma and a third of patients with lung squamous cell carcinoma. In lung adenocarcinoma, KEAP1 loss often co-occurs with STK11 loss and KRAS-activating alterations. Despite its prevalence, the impact of NRF2 activation on tumor progression and patient outcomes is not fully defined.

EXPERIMENTAL DESIGN

We model NRF2 activation, STK11 loss, and KRAS activation in vivo using novel genetically engineered mouse models. Furthermore, we derive a NRF2 activation signature from human non-small cell lung tumors that we use to dissect how these genomic events impact outcomes and immune contexture of participants in the OAK and IMpower131 immunotherapy trials.

RESULTS

Our in vivo data reveal roles for NRF2 activation in (i) promoting rapid-onset, multifocal intrabronchiolar carcinomas, leading to lethal pulmonary dysfunction, and (ii) decreasing elevated redox stress in KRAS-mutant, STK11-null tumors. In patients with nonsquamous tumors, the NRF2 signature is negatively prognostic independently of STK11 loss. Patients with lung squamous cell carcinoma with low NRF2 signature survive longer when receiving anti-PD-L1 treatment.

CONCLUSIONS

Our in vivo modeling establishes NRF2 activation as a critical oncogenic driver, cooperating with STK11 loss and KRAS activation to promote aggressive lung adenocarcinoma. In patients, oncogenic events alter the tumor immune contexture, possibly having an impact on treatment responses. Importantly, patients with NRF2-activated nonsquamous or squamous tumors have poor prognosis and show limited response to anti-PD-L1 treatment.

Molecular Mechanisms of Hepatoblastoma

Hepatoblastoma (HB) is the predominant primary liver tumor in children. While the prognosis is favorable when the tumor can be resected, the outcome is dismal for patients with progressed HB. Therefore, a better understanding of the molecular mechanisms responsible for HB is imperative for early detection and effective treatment. Sequencing analysis of human HB specimens unraveled the pivotal role of Wnt/β-catenin pathway activation in this disease. Nonetheless, β-catenin activation alone does not suffice to induce HB, implying the need for additional alterations. Perturbations of several pathways, including Hippo, Hedgehog, NRF2/KEAP1, HGF/c-Met, NK-1R/SP, and PI3K/AKT/mTOR cascades and aberrant activation of c-MYC, n-MYC, and EZH2 proto-oncogenes, have been identified in HB, although their role requires additional investigation. Here, we summarize the current knowledge on HB molecular pathogenesis, the relevance of the preclinical findings for the human disease, and the innovative therapeutic strategies that could be beneficial for the treatment of HB patients.

Combination of Dendrobium Mixture and Metformin Curbs the Development and Progression of Diabetic Cardiomyopathy by Targeting the lncRNA NEAT1

OBJECTIVES

This study aimed to explore the efficacy of combination treatment with dendrobium mixture and metformin (Met) in diabetic cardiomyopathy (DCM) and its effects on NEAT1 and the Nrf2 signaling pathway.

METHODS

H9c2 cells were maintained in medium supplemented with either low (5.5 mmol/L) or high (50 mmol/L) glucose. Male Sprague-Dawley rats were fed a high-glucose diet and administered a single, low dose of streptozotocin (35 mg/kg) via intraperitoneal injection to induce the development of DM. After induction of DM, the rats were treated with dendrobium mixture (10 g/kg) and Met (0.18 g/kg) daily for 4 weeks. Next, quantitative reverse transcription (qRT)-PCR and western blotting were performed to evaluate the expression levels of target genes and proteins. Flow cytometry was performed to assess apoptosis, and hematoxylin and eosin staining was performed to evaluate the morphological changes in rat cardiac tissue.

RESULTS

In patients with diabetes mellitus (DM) and myocardial cells and heart tissues from rats with high glucose-induced DM, NEAT1 was downregulated, and the expression levels of Nrf2 were decreased (p<0.01, p<0.001). The combination of dendrobium mixture and Met upregulated the expression of NEAT1 which upregulated Nrf2 by targeting miR-23a-3p, resulting in reduced apoptosis and improved cardiac tissue morphology (p<0.01, p<0.001).

CONCLUSION

Dendrobium mixture and Met upregulated the expression of NEAT1 in DCM, thereby inhibiting apoptosis of myocardial cells.

Nasal administration of mitochondria reverses chemotherapy-induced cognitive deficits

Up to seventy-five percent of patients treated for cancer suffer from cognitive deficits which can persist for months to decades, severely impairing quality of life. Although the number of cancer survivors is increasing tremendously, no efficacious interventions exist. Cisplatin, most commonly employed for solid tumors, leads to cognitive impairment including deficits in memory and executive functioning. We recently proposed deficient neuronal mitochondrial function as its underlying mechanism. We hypothesized nasal administration of mitochondria isolated from human mesenchymal stem cells to mice, can reverse cisplatin-induced cognitive deficits. Methods: Puzzle box, novel object place recognition and Y-maze tests were used to assess the cognitive function of mice. Immunofluorescence and high-resolution confocal microscopy were employed to trace the nasally delivered mitochondria and evaluate their effect on synaptic loss. Black Gold II immunostaining was used to determine myelin integrity. Transmission electron microscopy helped determine mitochondrial and membrane integrity of brain synaptosomes. RNA-sequencing was performed to analyse the hippocampal transcriptome. Results: Two nasal administrations of mitochondria isolated from human mesenchymal stem cells to mice, restored executive functioning, working and spatial memory. Confocal imaging revealed nasally delivered mitochondria rapidly arrived in the meninges where they were readily internalized by macrophages. The administered mitochondria also accessed the rostral migratory stream and various other brain regions including the hippocampus where they colocalized with GFAP+ cells. The restoration of cognitive function was associated with structural repair of myelin in the cingulate cortex and synaptic loss in the hippocampus. Nasal mitochondrial donation also reversed the underlying synaptosomal mitochondrial defects. Moreover, transcriptome analysis by RNA-sequencing showed reversal of cisplatin-induced changes in the expression of about seven hundred genes in the hippocampus. Pathway analysis identified Nrf2-mediated response as the top canonical pathway. Conclusion: Our results provide key evidence on the therapeutic potential of isolated mitochondria - restoring both brain structure and function, their capability to enter brain meninges and parenchyma upon nasal delivery and undergo rapid cellular internalization and alter the hippocampal transcriptome. Our data identify nasal administration of mitochondria as an effective strategy for reversing chemotherapy-induced cognitive deficits and restoring brain health, providing promise for the growing population of both adult and pediatric cancer survivors.

Cruciferous vegetables (Brassica oleracea) confer cytoprotective effects in Drosophila intestines

Varieties and cultivars of the cruciferous vegetable Brassica oleracea are widely presumed to elicit positive influences on mammalian health and disease, particularly related to their indole and sulforaphane content. However, there is a considerable gap in knowledge regarding the mechanisms whereby these plant-derived molecules elicit their beneficial effects on the host. In this study, we examined the chemical variation between B. oleracea varieties and evaluated their capacity to both activate Nrf2 in the Drosophila intestine and elicit cytoprotection. Ten types of edible B. oleracea were purchased and B. macrocarpa was wild collected. Fresh material was dried, extracted by double maceration and green kale was also subjected to anaerobic fermentation before processing. Untargeted metabolomics was used to perform Principal Component Analysis. Targeted mass spectral analysis determined the presence of six indole species and quantified indole. Extracts were tested for their capacity to activate Nrf2 in the Drosophila intestine in third instar Drosophila larvae. Cytoprotective effects were evaluated using a paraquat-induced oxidative stress gut injury model. A "Smurf" assay was used to determine protective capacity against a chemically induced leaky gut. Extracts of Brussels sprouts and broccoli activated Nrf2 and protected against paraquat-induced damage and leaky gut. Lacto-fermented kale showed a cytoprotective effect, increasing survival by 20% over the non-fermented extract, but did not protect against leaky gut. The protective effects observed do not directly correlate with indole content, suggesting involvement of multiple compounds and a synergistic mechanism.

Selenium modulates inorganic mercury induced cytotoxicity and intrinsic apoptosis in PC12 cells

Mercury (Hg) in its all forms, including inorganic Hg (iHg) is an environmental contaminant due to toxicity and diseases in human. However, a little is known about the underlying mechanisms responsible for iHg toxicity. Selenium (Se) is an essential trace element, recognized as an antioxidant and protective agent against metal toxicities. The purpose of this research was to investigate ameliorations of Se counter to iHg-mediated toxicity in PC12 cells. Cytotoxic assays have been shown that iHg (5 μM) caused oxidative stress and intrinsic apoptosis via ROS generation, oxidizing glutathione, damaging DNA, degrading cell membrane integrity, down-regulating mTOR, p-mTOR, akt and ERK1, and up-regulating cleaved caspase 3 and cytochrome c release in PC12 cells 48 h after incubation. Co-treatment of Se (5 μM) inhibited intrinsic apoptosis and oxidative stress induced by iHg (5 μM) via inhibiting ROS formation, boosting GPx contents, increasing reduced glutathione, limiting DNA degradation, improving cell membrane integrity, up-regulating mTOR, p-mTOR, akt, ERK1 and caspase 3, and down-regulating cleaved caspase 3 and cytochrome c leakage in PC12 cells. In conclusion, these results recommended that excessive ROS generation acts a critical role in iHg-influenced oxidative stress and co-treatment of Se attenuates iHg-cytotoxicity through its antioxidant properties.

The Protective Role of Prenatal Alpha Lipoic Acid Supplementation against Pancreatic Oxidative Damage in Offspring of Valproic Acid-Treated Rats: Histological and Molecular Study

Background: Sodium valproate (VPA) is an antiepileptic drug (AED) licensed for epilepsy and used during pregnancy in various indications. Alpha-lipoic acid (ALA) is a natural compound inducing endogenous antioxidant production. Our study aimed to investigate the effect of prenatal administration of VPA on the pancreas of rat offspring and assess the potential protective role of ALA co-administration during pregnancy. Methods: Twenty-eight pregnant female albino rats were divided into four groups: group I (negative control), group II (positive control, ALA treated), group III (VPA-treated), and group IV (VPA-ALA-treated). The pancreases of the rat offspring were removed at the fourth week postpartum and prepared for histological, immune-histochemical, morphometric, molecular, and oxidative stress marker studies. Results: In group III, there were pyknotic nuclei, vacuolated cytoplasm with ballooning of acinar, α, and β cells of the pancreas. Ultrastructural degeneration of cytoplasmic organelles was detected. Additionally, there was a significant increase in oxidative stress, a decrease in insulin-positive cell percentage, and an increase in glucagon positive cells in comparison to control groups. Moreover, VPA increased the gene expression of an apoptotic marker, caspase-3, with a decrease in anti-apoptotic Bcl2 and nuclear factor erythroid 2-related factor 2 (Nrf2) transcriptional factor. Conversely, ALA improved oxidative stress and apoptosis in group VI, and a consequent improvement of the histological and ultrastructure picture was detected. Conclusion: ALA co-administration with VPA significantly improved the oxidative stress condition, histological and morphometric picture of the pancreas, and restored normal expression of related genes, including Nrf2, caspase-3, and Bcl-2. Administration of α-lipoic acid has a protective effect against VPA-induced pancreatic oxidative damage via its cytoprotective antioxidant effect.

Transcription Factor Nrf2 as a Potential Therapeutic Target for Prevention of Cytokine Storm in COVID-19 Patients

Nrf2 is a key transcription factor responsible for antioxidant defense in many tissues and cells, including alveolar epithelium, endothelium, and macrophages. Furthermore, Nrf2 functions as a transcriptional repressor that inhibits expression of the inflammatory cytokines in macrophages. Critically ill patients with COVID-19 infection often present signs of high oxidative stress and systemic inflammation - the leading causes of mortality. This article suggests rationale for the use of Nrf2 inducers to prevent development of an excessive inflammatory response in COVID-19 patients.

Autophagy suppresses TRP53/p53 and oxidative stress to enable mammalian survival

Macroautophagy (hereafter autophagy) plays an important role in maintaining cellular homeostasis under stress conditions. We previously demonstrated that conditional autophagy deficiency in adult mice causes selective tissue damage, is lethal upon fasting, and shortens lifespan to less than three months primarily due to neurodegeneration, but not all the mechanisms are known. We conditionally deleted Trp53/p53 and/or the essential autophagy gene Atg7 throughout adult mice to test whether TRP53 is responsible for any of these phenotypes. atg7^Δ/Δ trp53^Δ/Δ mice have extended lifespan due to delayed tissue damage and neurodegeneration, and are resistant to death upon fasting compared to atg7^Δ/Δ mice. Atg7 also suppresses apoptosis induced by the TRP53 activator Nutlin-3 in liver and brain. We then deleted Atg7 in the presence or absence of the master regulator of antioxidant defense NFE2L2/NRF2 (nuclear factor, erythroid derived 2, like 2) to test if increased oxidative stress causes TRP53 activation in atg7^Δ/Δ mice. nfe2l2^-/-atg7^Δ/Δ mice die rapidly due to intestinal damage, which is not rescued by trp53 co-deletion. Therefore, these data demonstrate the tissue specificities and functional dependencies between autophagy, TRP53 and NFE2L2 stress response mechanisms.