Mechanisms of activation of the transcription factor Nrf2 by redox stressors, nutrient cues, and energy status and the pathways through which it attenuates degenerative disease

A bioactive sprite: Recent advances in the application of vinyl sulfones in drug design and organic synthesis

Vinyl sulfones, with their exceptional chemical properties, are known as the "chameleons" of organic synthesis and are widely used in the preparation of various sulfur-containing structures. However, their most alluring feature lies in their biological activity. The vinyl sulfone skeleton is ubiquitous in natural products and drug molecules and boasts a unique molecular structure and drug activity when compared to conventional drug molecules. As a result, vinyl sulfones have been extensively studied, playing a critical role in organic synthesis and pharmaceutical chemistry. In this review, we present a comprehensive analysis of the recent applications of vinyl sulfone structures in drug design, biology, and chemical synthesis. Furthermore, we explore the prospects of vinyl sulfones in diverse fields, offering insight into their potential future applications.

The Citrus flavanone naringenin prolongs the lifespan in C. elegans and slows signs of brain aging in mice

Aging is one of the main risk factors for neurodegenerative disorders, which represent a global burden on healthcare systems. Therefore, identifying new strategies to slow the progression of brain aging is a compelling challenge. In this article, we first assessed the potential anti-aging effects of the Citrus flavanone naringenin (NAR), an activator of the enzyme sirtuin-1 (SIRT1), in a 3R-compliant and short-lived aging model (i.e., the nematode C. elegans). Then, we investigated the preventive effects of a 6-month treatment with NAR (100 mg/kg, orally) against brain aging and studied its mechanism of action in middle-aged mice. We demonstrated that NAR (100 μM) extends lifespan and improves healthspan in C. elegans. In the brain of middle-aged mice, NAR promotes the activity of metabolic enzymes (citrate synthase, cytochrome C oxidase) and increases the expression of the SIRT1 enzyme. Consistently, NAR up-regulates the expression of downstream antioxidant (Foxo3, Nrf2, Ho-1), anti-senescence (p16), and anti-inflammatory (Il-6, Il-18) markers. Our findings support NAR supplementation to slow the signs of brain aging.

Unlocking peak performance: The role of Nrf2 in enhancing exercise outcomes and training adaptation in humans

Since the discovery of the nuclear factor erythroid-derived 2-like 2 (Nrf2) transcription factor thirty years ago, it has been shown that it regulates more than 250 genes involved in a multitude of biological processes, including redox balance, mitochondrial biogenesis, metabolism, detoxification, cytoprotection, inflammation, immunity, autophagy, cell differentiation, and xenobiotic metabolism. In skeletal muscle, Nrf2 signalling is primarily activated in response to perturbation of redox balance by reactive oxygen species or electrophiles. Initial investigations into human skeletal muscle Nrf2 responses to exercise, dating back roughly a decade, have consistently indicated that exercise-induced ROS production stimulates Nrf2 signalling. Notably, recent studies employing Nrf2 knockout mice have revealed impaired skeletal muscle contractile function characterised by reduced force output and increased fatigue susceptibility compared to wild-type counterparts. These deficiencies partially stem from diminished basal mitochondrial respiratory capacity and an impaired capacity to upregulate specific mitochondrial proteins in response to training, findings corroborated by inducible muscle-specific Nrf2 knockout models. In humans, baseline Nrf2 expression in skeletal muscle correlates with maximal oxygen uptake and high-intensity exercise performance. This manuscript delves into the mechanisms underpinning Nrf2 signalling in response to acute exercise in human skeletal muscle, highlighting the involvement of ROS, antioxidants and Keap1/Nrf2 signalling in exercise performance. Furthermore, it explores Nrf2's role in mediating adaptations to chronic exercise and its impact on overall exercise performance. Additionally, the influence of diet and certain supplements on basal Nrf2 expression and its role in modulating acute and chronic exercise responses are briefly addressed.

Nrf2-Mediated Antioxidant Response and Drug Efflux Transporters Upregulation as Possible Mechanisms of Resistance in Photodynamic Therapy of Cancers

Photodynamic therapy (PDT) is a groundbreaking approach involving the induction of cytotoxic reactive oxygen species (ROS) within tumors through visible light activation of photosensitizers (PS) in the presence of molecular oxygen. This innovative therapy has demonstrated success in treating various cancers. While PDT proves highly effective in most solid tumors, there are indications that certain cancers exhibit resistance, and some initially responsive cancers may develop intrinsic or acquired resistance to PDT. The molecular mechanisms underlying this resistance are not fully understood. Recent evidence suggests that, akin to other traditional cancer treatments, the activation of survival pathways, such as the KEAP1/Nrf2 signaling pathway, is emerging as an important mechanism of post-PDT resistance in many cancers. This article explores the dual role of Nrf2, highlighting evidence linking aberrant Nrf2 expression to treatment resistance across a range of cancers. Additionally, it delves into the specific role of Nrf2 in the context of photodynamic therapy for cancers, emphasizing evidence that suggests Nrf2-mediated upregulation of antioxidant responses and induction of drug efflux transporters are potential mechanisms of resistance to PDT in diverse cancer types. Therefore, understanding the specific role(s) of Nrf2 in PDT resistance may pave the way for the development of more effective cancer treatments using PDT.

A Novel Analog of the Natural Product Fraxinellone Protects against Endogenous and Exogenous Neurotoxicants

Numerous insults, both endogenous (e.g., glutamate) and exogenous (e.g., pesticides), compromise the function of the nervous system and pose risk factors for damage or later disease. In previous reports, limonoids such as fraxinellone showed significant neuroprotective activity against glutamate (Glu) excitotoxicity and reactive oxygen species (ROS) production in vitro, albeit with minimal mechanistic information provided. Given these findings, a library of novel fraxinellone analogs (including analogs 1 and 2 described here) was synthesized with the goal of identifying compounds exhibiting neuroprotection against insults. Analog 2 was found to be protective against Glu-mediated excitotoxicity with a measured EC50 of 44 and 39 nM for in vitro assays using PC12 and SH-SY5Y cells, respectively. Pretreatment with analog 2 yielded rapid induction of antioxidant genes, namely, Gpx4, Sod1, and Nqo1, as measured via qPCR. Analog 2 mitigated Glu-mediated ROS. Cytoprotection could be replicated using sulforaphane (SFN), a Nrf2 activator, and inhibited via ML-385, which inhibits Nrf2 binding to regulatory DNA sequences, thereby blocking downstream gene expression. Nrf2 DNA-binding activity was demonstrated using a Nrf2 ELISA-based transcription factor assay. In addition, we found that pretreatment with the thiol N-acetyl Cys completely mitigated SFN-mediated induction of antioxidant genes but had no effect on the activity of analog 2, suggesting thiol modification is not critical for its mechanism of action. In summary, our data demonstrate a fraxinellone analog to be a novel, potent, and rapid activator of the Nrf2-mediated antioxidant defense system, providing robust protection against insults.

Regulation of Keap1-Nrf2 signaling in health and diseases

Nuclear factor erythroid 2-related factor 2 (Nrf2) functions as a central regulator in modulating the activities of diverse antioxidant enzymes, maintaining cellular redox balance, and responding to oxidative stress (OS). Kelch-like ECH-associated protein 1 (Keap1) serves as a principal negative modulator in controlling the expression of detoxification and antioxidant genes. It is widely accepted that OS plays a pivotal role in the pathogenesis of various diseases. When OS occurs, leading to inflammatory infiltration of neutrophils, increased secretion of proteases, and the generation of large quantities of reactive oxygen radicals (ROS). These ROS can oxidize or disrupt DNA, lipids, and proteins either directly or indirectly. They also cause gene mutations, lipid peroxidation, and protein denaturation, all of which can result in disease. The Keap1-Nrf2 signaling pathway regulates the balance between oxidants and antioxidants in vivo, maintains the stability of the intracellular environment, and promotes cell growth and repair. However, the antioxidant properties of the Keap1-Nrf2 signaling pathway are reduced in disease. This review overviews the mechanisms of OS generation, the biological properties of Keap1-Nrf2, and the regulatory role of its pathway in health and disease, to explore therapeutic strategies for the Keap1-Nrf2 signaling pathway in different diseases.

Emodin alleviates intestinal ischemia-reperfusion injury through antioxidant stress, anti-inflammatory responses and anti-apoptosis effects via Akt-mediated HO-1 upregulation

BACKGROUND

Intestinal ischemia-reperfusion (I/R) injury is a severe vascular emergency. Previous research indicated the protective effects of Emodin on I/R injury. Our study aims to explore the effect of Emodin on intestinal I/R (II/R) injury and elucidate the underlying mechanisms.

METHODS

C57BL/6 mice and Caco-2 cells were used for in vivo and in vitro studies. We established an animal model of II/R injury by temporarily occluding superior mesenteric artery. We constructed an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model using a hypoxia-reoxygenation incubator. Different doses of Emodin were explored to determine the optimal therapeutic dose. Additionally, inhibitors targeting the protein kinase B (Akt) or Heme oxygenase-1 (HO-1) were administered to investigate their potential protective mechanisms.

RESULTS

Our results demonstrated that in animal experiments, Emodin mitigated barrier disruption, minimized inflammation, reduced oxidative stress, and inhibited apoptosis. When Akt or HO-1 was inhibited, the protective effect of Emodin was eliminated. Inhibiting Akt also reduced the level of HO-1. In cell experiments, Emodin reduced inflammation and apoptosis in the OGD/R cell model. Additionally, when Akt or HO-1 was inhibited, the protective effect of Emodin was weakened.

CONCLUSIONS

Our findings suggest that Emodin may protect the intestine against II/R injury through the Akt/HO-1 signaling pathway.

Lemon extract reduces the hepatic oxidative stress and persulfidation levels by upregulating the Nrf2 and Trx1 expression in old rats

Citrus flavanones are recognized as promising bioactives within the concept of healthy aging. Thus, the present study investigated the effects of a nutritionally relevant dose of lemon extract (LE) on liver redox regulation and persulfidation levels in 24-month-old Wistar rats. LE (40 mg/kg b.m.) was administered orally once daily for 4 weeks. Control groups received either vehicle (sunflower oil) or remained intact. The applied methodology considered qPCR, Western blot, protein persulfidation levels evaluation, histochemistry in line with immunofluorescence, liver biochemical assays (glutathione, total -SH groups and malonaldehyde; MDA), liver enzymes in serum and in silico analysis to explore the potential interaction/binding between the proteins studied in the paper. Our results showed that LE increased glutathione peroxidase (GPx), reductase (GR), glutamate-cysteine ligase catalytic and modifier subunit, respectively, as well as Nrf2 gene expressions, but decreased the expression of superoxide dismutase 2 (SOD2). Upon LE application, protein expression showed upregulation of NRF2, SOD2, GPx, GR, and thioredoxin 1 (Trx1). LE significantly decreased the protein persulfidation levels and concentration of MDA, a marker of oxidative damage in the cell. Histological analysis showed a normal liver histoarchitecture without pathological changes, aligning with the normal serum level of hepatic enzymes. Obtained results showed that LE, by modulating hepatic redox regulators Nrf2 and Trx1, diminishes oxidative stress and alters the persulfidation levels, suggesting a considerable beneficial antioxidant potential of lemon flavanones in the old-aged liver.

Binge alcohol induces NRF2-related antioxidant response in the skeletal muscle of female mice

BACKGROUND

Chronic alcohol enhances oxidative stress, but the temporal response of antioxidant genes in skeletal muscle following a binge drinking episode remains unknown.

METHODS

Experiment 1: C57BL/6Hsd female mice received an IP injection of saline (CON; n = 39) or ethanol (ETOH; n = 39) (5 g/kg). Gastrocnemius muscles were collected from baseline (untreated; n = 3), CON (n = 3), and ETOH (n = 3) mice every 4 h for 48 h. Experiment 2: Gastrocnemius muscles were collected from control-fed (CON-FED; n = 17), control-fasted (CON-FAST; n = 18), or alcohol-fed (ETOH-FED; n = 18) mice every 4hrs for 20hrs after saline or ethanol (5 g/kg).

RESULTS

EtOH enhanced Superoxide dismutase 1 (Sod1) and NADPH Oxidase 4 (Nox4) from 24 to 48hr after the binge, while Sod2 and Nox2 were suppressed. Nuclear factor erythroid-derived 2-like 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) increased 12hrs after intoxication. Cytochrome P450 oxidoreductase (Por), Heme oxygenase 1 (Ho1), Peroxiredoxin 6 (Prdx6), Glutamate-cysteine ligase catalytic subunit (Gclc), Glutamate-cysteine ligase modifier subunit (Gclm), and Glutathione-disulfide reductase (Gsr) were increased by ETOH starting 12-16hrs post-binge. Fasting had similar effects on Nrf2 compared to alcohol, but downstream targets of NRF2, including Por, Ho1, Gclc, and Gclm, were differentially altered with fasting and EtOH.

CONCLUSION

These data suggest that acute alcohol intoxication induced markers of oxidative stress and antioxidant signaling through the NRF2 pathway and that there were effects of alcohol independent of a possible decrease in food intake caused by binge intoxication.

Albizzia chinensis (Osbeck) Merr extract YS ameliorates ethanol-induced acute gastric ulcer injury in rats by regulating NRF2 signaling pathway

BACKGROUND

Around the world, there is a high incidence of gastric ulcers. YS, an extract from the Chinese herb Albizzia chinensis (Osbeck) Merr, has potential therapeutic applications for gastrointestinal diseases. Here we elucidated the protective effect and underlying mechanism of action of YS on gastric ulcer in rats injured by ethanol.

METHODS

The ethanol-induced gastric ulcer rat model was used to assess the protective effect of YS. A pathological examination of gastric tissue was performed by H&E staining. GES-1 cells damaged by hydrogen peroxide were used to simulate oxidative damage in gastric mucosal epithelial cells. Endogenous NRF2 was knocked down using small interfering RNA. Immunoprecipitation was used to detect ubiquitination of NRF2. Co-immunoprecipitation was used to detect the NRF2-Keap1 interaction.

RESULTS

YS (10 and 30 mg/kg, i.g.) significantly reduced the ulcer index, decreased MDA level, and increased SOD and GSH levels in gastric tissues damaged by ethanol. YS promoted NRF2 translocation from cytoplasm to nucleus and enhanced the NQO1 and HO-1 expression levels in injured rat gastric tissue. In addition, YS regulated NQO1 and HO-1 via NRF2 in H2O2-induced oxidative injured GES-1 cells. Further studies on the underlying mechanism indicated that YS reduced the interaction between NRF2 and Keap1 and decreased ubiquitylation of NRF2, thereby increasing its stability and expression of downstream factors. NRF2 knockdown abolished the effect of YS on MDA and SOD in GES-1 cells treated with H2O2.

CONCLUSION

YS reduced the NRF2-Keap1 interaction, promoting NRF2 translocation into the nucleus, which increasing the transcription and translation of NQO1 and HO-1 and improved the antioxidant capacity of rat stomach.

Modulation of neuroinflammation and oxidative stress by targeting GPR55 - new approaches in the treatment of psychiatric disorders

Pharmacological treatment of psychiatric disorders remains challenging in clinical, pharmacological, and scientific practice. Even if many different substances are established for treating different psychiatric conditions, subgroups of patients show only small or no response to the treatment. The neuroinflammatory hypothesis of the genesis of psychiatric disorders might explain underlying mechanisms in these non-responders. For that reason, recent research focus on neuroinflammatory processes and oxidative stress as possible causes of psychiatric disorders. G-protein coupled receptors (GPCRs) form the biggest superfamily of membrane-bound receptors and are already well known as pharmacological targets in various diseases. The G-protein coupled receptor 55 (GPR55), a receptor considered part of the endocannabinoid system, reveals promising modulation of neuroinflammatory and oxidative processes. Different agonists and antagonists reduce pro-inflammatory cytokine release, enhance the synthesis of anti-inflammatory mediators, and protect cells from oxidative damage. For this reason, GPR55 ligands might be promising compounds in treating subgroups of patients suffering from psychiatric disorders related to neuroinflammation or oxidative stress. New approaches in drug design might lead to new compounds targeting different pathomechanisms of those disorders in just one molecule.

RBM3 Ameliorates Acute Brain Injury-induced Inflammation and Oxidative Stress by Stabilizing GAS6 mRNA Through Nrf2 Signaling Pathway

RNA-binding motif protein 3 (RBM3), as a cold-inducible protein, exhibits neuroprotective function in brain disorders. This study was conducted to investigate the effects of RBM3 on acute brain injury (ABI) and its underlying mechanism. The cerebral injury (CI) rat model and oxygen-glucose deprivation (OGD) cell model were established. The neurological severity score, wire-grip score, morris water maze test, and Y-maze test were used to detect the neurological damage, vestibular motor, learning, and memory functions. Cerebral injury, apoptosis, oxidative stress, and inflammatory level were evaluated by hematoxylin-eosin and TUNEL staining and specific kits. Flow cytometry was used to analyze the apoptosis rate. The relationship between RBM3 and growth arrest specific (GAS) 6 was analyzed by RNA immunoprecipitation assay. The results indicated that RBM3 recovered of neurological function and behaviour impairment of CI rats. Additionally, RBM3 reversed the increased oxidative stress, inflammatory level, and apoptosis induced by CI and OGD. RBM3 interacted with GAS6 to activate the Nrf2 signaling pathway, thus playing neuroprotection on ABI. Besides, the results of RBM3 treatment were similar to those of mild hypothermia treatment. In summary, RBM3 exerted neuroprotection and ameliorated inflammatory levels and oxidative stress by stabilizing GAS6 mRNA through the Nrf2 signaling pathway, suggesting that RBM3 might be a potential therapeutic candidate for treating ABI.

Hepatic WDR23 proteostasis mediates insulin homeostasis by regulating insulin-degrading enzyme capacity

Maintaining insulin homeostasis is critical for cellular and organismal metabolism. In the liver, insulin is degraded by the activity of the insulin-degrading enzyme (IDE). Here, we establish a hepatic regulatory axis for IDE through WDR23-proteostasis. Wdr23KO mice have increased IDE expression, reduced circulating insulin, and defective insulin responses. Genetically engineered human cell models lacking WDR23 also increase IDE expression and display dysregulated phosphorylation of insulin signaling cascade proteins, IRS-1, AKT2, MAPK, FoxO, and mTOR, similar to cells treated with insulin, which can be mitigated by chemical inhibition of IDE. Mechanistically, the cytoprotective transcription factor NRF2, a direct target of WDR23-Cul4 proteostasis, mediates the enhanced transcriptional expression of IDE when WDR23 is ablated. Moreover, an analysis of human genetic variation in WDR23 across a large naturally aging human cohort in the US Health and Retirement Study reveals a significant association of WDR23 with altered hemoglobin A1C (HbA1c) levels in older adults, supporting the use of WDR23 as a new molecular determinant of metabolic health in humans.

Oxidative Stress in Breast Cancer: A Biochemical Map of Reactive Oxygen Species Production

This review systematizes information about the metabolic features of breast cancer directly related to oxidative stress. It has been shown those redox changes occur at all levels and affect many regulatory systems in the human body. The features of the biochemical processes occurring in breast cancer are described, ranging from nonspecific, at first glance, and strictly biochemical to hormone-induced reactions, genetic and epigenetic regulation, which allows for a broader and deeper understanding of the principles of oncogenesis, as well as maintaining the viability of cancer cells in the mammary gland. Specific pathways of the activation of oxidative stress have been studied as a response to the overproduction of stress hormones and estrogens, and specific ways to reduce its negative impact have been described. The diversity of participants that trigger redox reactions from different sides is considered more fully: glycolytic activity in breast cancer, and the nature of consumption of amino acids and metals. The role of metals in oxidative stress is discussed in detail. They can act as both co-factors and direct participants in oxidative stress, since they are either a trigger mechanism for lipid peroxidation or capable of activating signaling pathways that affect tumorigenesis. Special attention has been paid to the genetic and epigenetic regulation of breast tumors. A complex cascade of mechanisms of epigenetic regulation is explained, which made it possible to reconsider the existing opinion about the triggers and pathways for launching the oncological process, the survival of cancer cells and their ability to localize.

New insights into changes in phosphorus profile at sediment-water interface by microplastics: Role of benthic bioturbation

Microplastics (MPs) have attracted increasing attention due to their ubiquitous occurrence in freshwater sediments and the detrimental effects on benthic invertebrates. However, a clear understanding of their downstream impacts on ecosystem services is still lacking. This study examines the effects of bio-based polylactic acid (PLA), fuel-based polyethylene terephthalate (PET), and biofilm-covered PET (BPET) MPs on the bioturbator chironomid larvae (Tanypus chinensis), and the influence on phosphorus (P) profiles in microcosms. The changes in biochemical responses and metabolic pathways indicated that MPs disrupted energy synthesis by causing intestinal blockage and oxidative stress in T. chinensis, leading to energy depletion and impaired bioturbation activity. The impairment further resulted in enhanced sedimentary P immobilization. For larval treatments, the internal-P loadings were respectively 11.4%, 8.6%, and 9.0% higher in the PLA, PET, and BPET groups compared to the non-MP control. Furthermore, the influence of bioturbation on P profiles was MP-type dependent. Both BPET and PLA treatments displayed more obvious impacts on P profiles compared to PET due to the changes in MP bioavailability or sediment microenvironment. This study connects individual physiological responses to broader ecosystem services, showing that MPs alter P biogeochemical processes by disrupting the bioturbation activities of chironomid larvae.

Inhibition of glycogen synthase kinase-3 enhances NRF2 protein stability, nuclear localisation and target gene transcription in pancreatic beta cells

Accumulation of reactive oxygen species (i.e., oxidative stress) is a leading cause of beta cell dysfunction and apoptosis in diabetes. NRF2 (NF-E2 p45-related factor-2) regulates the adaptation to oxidative stress, and its activity is negatively regulated by the redox-sensitive CUL3 (cullin-3) ubiquitin ligase substrate adaptor KEAP1 (Kelch-like ECH-associated protein-1). Additionally, NRF2 is repressed by the insulin-regulated Glycogen Synthase Kinase-3 (GSK3). We have demonstrated that phosphorylation of NRF2 by GSK3 enhances β-TrCP (beta-transducin repeat-containing protein) binding and ubiquitylation by CUL1 (cullin-1), resulting in increased proteasomal degradation of NRF2. Thus, we hypothesise that inhibition of GSK3 activity or β-TrCP binding upregulates NRF2 and so protects beta cells against oxidative stress. We have found that treating the pancreatic beta cell line INS-1 832/13 with the KEAP1 inhibitor TBE31 significantly enhanced NRF2 protein levels. The presence of the GSK3 inhibitor CT99021 or the β-TrCP-NRF2 protein-protein interaction inhibitor PHAR, along with TBE31, resulted in prolonged NRF2 stability and enhanced nuclear localisation (P < 0.05). TBE31-mediated induction of NRF2-target genes encoding NAD(P)H quinone oxidoreductase 1 (Nqo1), glutamate-cysteine ligase modifier (Gclm) subunit and heme oxygenase (Hmox1) was significantly enhanced by the presence of CT99021 or PHAR (P < 0.05) in both INS-1 832/13 and in isolated mouse islets. Identical results were obtained using structurally distinct GSK3 inhibitors and inhibition of KEAP1 with sulforaphane. In summary, we demonstrate that GSK3 and β-TrCP/CUL1 regulate the proteasomal degradation of NRF2, enhancing the impact of KEAP1 regulation, and so contributes to the redox status of pancreatic beta cells. Inhibition of GSK3, or β-TrCP/CUL1 binding to NRF2 may represent a strategy to protect beta cells from oxidative stress.

Arenobufagin inhibits lung metastasis of colorectal cancer by targeting c-MYC/Nrf2 axis

BACKGROUND

Colorectal cancer (CRC) is one of the commonest cancers worldwide. Metastasis is the most common cause of death in patients with CRC. Arenobufagin is an active component of bufadienolides, extracted from toad skin and parotid venom. Arenobufagin reportedly inhibits epithelial-to-mesenchymal transition (EMT) and metastasis in various cancers. However, the mechanism through which arenobufagin inhibits CRC metastasis remains unclear.

PURPOSE

This study aimed to elucidate the molecular mechanisms by which arenobufagin inhibits CRC metastasis.

METHODS

Wound-healing and transwell assays were used to assess the migration and invasion of CRC cells. The expression of nuclear factor erythroid-2-related factor 2 (Nrf2) in the CRC tissues was assessed using immunohistochemistry. The protein expression levels of c-MYC and Nrf2 were detected by immunoblotting. A mouse model of lung metastasis was used to study the effects of arenobufagin on CRC lung metastasis in vivo.

RESULTS

Arenobufagin observably inhibited the migration and invasion of CRC cells by downregulating c-MYC and inactivating the Nrf2 signaling pathway. Pretreatment with the Nrf2 inhibitor brusatol markedly enhanced arenobufagin-mediated inhibition of migration and invasion, whereas pretreatment with the Nrf2 agonist tert‑butylhydroquinone significantly attenuated arenobufagin-mediated inhibition of migration and invasion of CRC cells. Furthermore, Nrf2 knockdown with short hairpin RNA enhanced the arenobufagin-induced inhibition of the migration and invasion of CRC cells. Importantly, c-MYC acts as an upstream modulator of Nrf2 in CRC cells. c-MYC knockdown markedly enhanced arenobufagin-mediated inhibition of the Nrf2 signaling pathway, cell migration, and invasion. Arenobufagin inhibited CRC lung metastasis in vivo. Together, these findings provide evidence that interruption of the c-MYC/Nrf2 signaling pathway is crucial for arenobufagin-inhibited cell metastasis in CRC.

CONCLUSIONS

Collectively, our findings show that arenobufagin could be used as a potential anticancer agent against CRC metastasis. The arenobufagin-targeted c-MYC/Nrf2 signaling pathway may be a novel chemotherapeutic strategy for treating CRC.

L-theanine abates oxidative stress and mitochondrial dysfunction in myocardial ischemia-reperfusion injury by positively regulating the antioxidant response

L-theanine (L-THE), a non-protein amino acid isolated from Camelia sinensis, has antioxidant properties that could prevent oxidative damage and mitochondrial dysfunction generated by myocardial ischemia and reperfusion (I/R) injury. The present study aimed to identify the effects of pretreatment with L-THE in rat hearts undergoing I/R. Wistar rats received vehicle or 250 mg/Kg L-THE intragastrically for 10 days. On day 11, hearts were removed under anesthesia and exposed to I/R injury in the Langendorff system. Measurement of left ventricular developed pressure and heart rate ex vivo demonstrates that L-THE prevents I/R-induced loss of cardiac function. Consequently, the infarct size of hearts subjected to I/R was significantly decreased when L-THE was administered. L-THE also mitigated I/R-induced oxidative injury in cardiac tissue by decreasing reactive oxygen species and malondialdehyde levels, while increasing the activity of antioxidant enzymes, SOD and CAT. Additionally, L-THE prevents oxidative phosphorylation breakdown and loss of inner mitochondrial membrane potential caused by I/R, restoring oxygen consumption levels, increasing respiratory control and phosphorylation efficiency, as well as buffering calcium overload. Finally, L-THE modifies the expression of genes involved in the antioxidant response through the overexpression of SOD1, SOD2 and CAT; as well as the transcriptional factors PPARα and Nrf2 in hearts undergoing I/R. In conclusion, L-THE confers cardioprotection against I/R injury by preventing oxidative stress, protecting mitochondrial function, and promoting overexpression of antioxidant genes. More studies are needed to place L-THE at the forefront of cardiovascular research and recommend its therapeutic use.

Oxidative stress, defective proteostasis and immunometabolic complications in critically ill patients

Oxidative stress (OS) develops in critically ill patients as a metabolic consequence of the immunoinflammatory and degenerative processes of the tissues. These induce increased and/or dysregulated fluxes of reactive species enhancing their pro-oxidant activity and toxicity. At the same time, OS sustains its own inflammatory and immunometabolic pathogenesis, leading to a pervasive and vitious cycle of events that contribute to defective immunity, organ dysfunction and poor prognosis. Protein damage is a key player of these OS effects; it generates increased levels of protein oxidation products and misfolded proteins in both the cellular and extracellular environment, and contributes to forms DAMPs and other proteinaceous material to be removed by endocytosis and proteostasis processes of different cell types, as endothelial cells, tissue resident monocytes-macrophages and peripheral immune cells. An excess of OS and protein damage in critical illness can overwhelm such cellular processes ultimately interfering with systemic proteostasis, and consequently with innate immunity and cell death pathways of the tissues thus sustaining organ dysfunction mechanisms. Extracorporeal therapies based on biocompatible/bioactive membranes and new adsorption techniques may hold some potential in reducing the impact of OS on the defective proteostasis of patients with critical illness. These can help neutralizing reactive and toxic species, also removing solutes in a wide spectrum of molecular weights thus improving proteostasis and its immunometabolic corelates. Pharmacological therapy is also moving steps forward which could help to enhance the efficacy of extracorporeal treatments. This narrative review article explores the aspects behind the origin and pathogenic role of OS in intensive care and critically ill patients, with a focus on protein damage as a cause of impaired systemic proteostasis and immune dysfunction in critical illness.

Roles of reactive oxygen species in inflammation and cancer

Reactive oxygen species (ROS) constitute a spectrum of oxygenic metabolites crucial in modulating pathological organism functions. Disruptions in ROS equilibrium span various diseases, and current insights suggest a dual role for ROS in tumorigenesis and the immune response within cancer. This review rigorously examines ROS production and its role in normal cells, elucidating the subsequent regulatory network in inflammation and cancer. Comprehensive synthesis details the documented impacts of ROS on diverse immune cells. Exploring the intricate relationship between ROS and cancer immunity, we highlight its influence on existing immunotherapies, including immune checkpoint blockade, chimeric antigen receptors, and cancer vaccines. Additionally, we underscore the promising prospects of utilizing ROS and targeting ROS modulators as novel immunotherapeutic interventions for cancer. This review discusses the complex interplay between ROS, inflammation, and tumorigenesis, emphasizing the multifaceted functions of ROS in both physiological and pathological conditions. It also underscores the potential implications of ROS in cancer immunotherapy and suggests future research directions, including the development of targeted therapies and precision oncology approaches. In summary, this review emphasizes the significance of understanding ROS-mediated mechanisms for advancing cancer therapy and developing personalized treatments.

Tiliroside attenuates acute kidney injury by inhibiting ferroptosis through the disruption of NRF2-KEAP1 interaction

BACKGROUND

Ferroptosis, an iron-dependent process that regulates cell death. Emerging evidences suggest that ferroptosis induces acute kidney injury (AKI) progression, and inhibiting ferroptosis provides an effect strategy for AKI treatment. The disruption of the NRF2-KEAP1 protein to protein interaction (PPI) induces NRF2 activation, which provides a promising strategy that can identify new ferroptosis inhibitors. A previous study revealed that tiliroside, a glycosidic flavonoid extracted from Edgeworthia chrysantha Lindl (buds), has anti-neuroinflammatory and neuroprotective effects via NRF2 activation. However, the mechanism through which tiliroside activates NRF2 is unknown, and it remains unclear whether it has protective effects against AKI.

PURPOSE

To investigate whether tiliroside has protective effects against AKI in mice and the associated mechanisms.

METHODS

Possible tiliroside substrates were analyzed using molecular docking. Cisplatin- and ischemia-reperfusion injury (IRI)-induced AKI mouse models and HK2 cells model were constructed to evaluate the protective effects of tiliroside. CRISPR/Cas9 mediated NRF2 knockout HK2 cells were used to verify whether NRF2 mediates tiliroside protective effects.

RESULTS

In vivo, our results showed that tiliroside treatment preserved kidney functions in AKI mice models, as showed by lower levels of serum creatinine (SCr), blood urea nitrogen (BUN), and renal injury markers, including neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM1), compared with the mice in control groups. In vitro, tiliroside treatment greatly ameliorated cisplatin-induced ferroptosis through NRF2 activation in cultured HK2 cells, as evidenced by the protective effects of tiliroside being greatly blunted after the knockout of NRF2 in HK2 cells. Mechanistic studies indicated that tiliroside promoted NRF2/GPX4 pathway activation and ferroptosis inhibition, perhaps via the disruption of the NRF2-KEAP1 PPI.

CONCLUSION

Together, our results demonstrate that tiliroside may serve as a NRF2-KEAP1 PPI inhibitor and prevents ferroptosis-induced AKI, indicating its potential for clinical AKI treatment.

An insight into role of amino acids as antioxidants via NRF2 activation

Oxidative stress can affect the protein, lipids, and DNA of the cells and thus, play a crucial role in several pathophysiological conditions. It has already been established that oxidative stress has a close association with inflammation via nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway. Amino acids are notably the building block of proteins and constitute the major class of nitrogen-containing natural products of medicinal importance. They exhibit a broad spectrum of biological activities, including the ability to activate NRF2, a transcription factor that regulates endogenous antioxidant responses. Moreover, amino acids may act as synergistic antioxidants as part of our dietary supplementations. This has aroused research interest in the NRF2-inducing activity of amino acids. Interestingly, amino acids' activation of NRF2-Kelch-like ECH-associated protein 1 (KEAP1) signaling pathway exerts therapeutic effects in several diseases. Therefore, the present review will discuss the relationship between different amino acids and activation of NRF2-KEAP1 signaling pathway pinning their anti-inflammatory and antioxidant properties. We also discussed amino acids formulations and their applications as therapeutics. This will broaden the prospect of the therapeutic applications of amino acids in a myriad of inflammation and oxidative stress-related diseases. This will provide an insight for designing and developing new chemical entities as NRF2 activators.

Protein Stability Regulation in Osteosarcoma: The Ubiquitin-like Modifications and Glycosylation as Mediators of Tumor Growth and as Targets for Therapy

The identification of new therapeutic targets and the development of innovative therapeutic approaches are the most important challenges for osteosarcoma treatment. In fact, despite being relatively rare, recurrence and metastatic potential, particularly to the lungs, make osteosarcoma a deadly form of cancer. In fact, although current treatments, including surgery and chemotherapy, have improved survival rates, the disease's recurrence and metastasis are still unresolved complications. Insights for analyzing the still unclear molecular mechanisms of osteosarcoma development, and for finding new therapeutic targets, may arise from the study of post-translational protein modifications. Indeed, they can influence and alter protein structure, stability and function, and cellular interactions. Among all the post-translational modifications, ubiquitin-like modifications (ubiquitination, deubiquitination, SUMOylation, and NEDDylation), as well as glycosylation, are the most important for regulating protein stability, which is frequently altered in cancers including osteosarcoma. This review summarizes the relevance of ubiquitin-like modifications and glycosylation in osteosarcoma progression, providing an overview of protein stability regulation, as well as highlighting the molecular mediators of these processes in the context of osteosarcoma and their possible targeting for much-needed novel therapy.

Protective Factors and the Pathogenesis of Complications in Diabetes

Chronic complications of diabetes are due to myriad disorders of numerous metabolic pathways that are responsible for most of the morbidity and mortality associated with the disease. Traditionally, diabetes complications are divided into those of microvascular and macrovascular origin. We suggest revising this antiquated classification into diabetes complications of vascular, parenchymal, and hybrid (both vascular and parenchymal) tissue origin, since the profile of diabetes complications ranges from those involving only vascular tissues to those involving mostly parenchymal organs. A major paradigm shift has occurred in recent years regarding the pathogenesis of diabetes complications, in which the focus has shifted from studies on risks to those on the interplay between risk and protective factors. While risk factors are clearly important for the development of chronic complications in diabetes, recent studies have established that protective factors are equally significant in modulating the development and severity of diabetes complications. These protective responses may help explain the differential severity of complications, and even the lack of pathologies, in some tissues. Nevertheless, despite the growing number of studies on this field, comprehensive reviews on protective factors and their mechanisms of action are not available. This review thus focused on the clinical, biochemical, and molecular mechanisms that support the idea of endogenous protective factors, and their roles in the initiation and progression of chronic complications in diabetes. In addition, this review also aimed to identify the main needs of this field for future studies.

AMPK Signaling Pathway as a Potential Therapeutic Target for Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease caused by the loss of dopaminergic neurons. Genetic factors, inflammatory responses, oxidative stress, metabolic disorders, cytotoxic factors, and mitochondrial dysfunction are all involved in neuronal death in neurodegenerative diseases. The risk of PD can be higher in aging individuals due to decreased mitochondrial function, energy metabolism, and AMP-activated protein kinase (AMPK) function. The potential of AMPK to regulate neurodegenerative disorders lies in its ability to enhance antioxidant capacity, reduce oxidative stress, improve mitochondrial function, decrease mitophagy and macroautophagy, and inhibit inflammation. In addition, it has been shown that modulating the catalytic activity of AMPK can protect the nervous system. This article reviews the mechanisms by which AMPK activation can modulate PD.

Nrf2 protein in melanoma progression, as a new means of treatment

Melanoma is a potentially lethal form of skin cancer resulting from the unlimited proliferation of melanocytes. Melanocytic lineage appears to have a greater rate of reactive oxygen species (ROS) production, possibly as a result of exposure to ultraviolet (UV) light and the production of melanin. It has been established that nuclear factor erythroid 2-related factor 2 (Nrf2) serves as a master regulator of the cellular response to oxidative stresses. Recent research has shown that the Nrf2 and its critical negative regulator Kelch-like ECH-associated protein 1 (Keap1) are misregulated in melanoma, and the Keap1-Nrf2 pathway has emerged as a promising new target for treating and preventing melanoma. In melanoma, Nrf2 may either limit tumor growth or promote its development. This review covers a wide range of topics, including the dual functions played by the Keap1-Nrf2 signaling pathway in melanoma and the most recent targeting techniques of the Nrf2.

Interactions between zinc and NRF2 in vascular redox signalling

Recent evidence highlights the importance of trace metal micronutrients such as zinc (Zn) in coronary and vascular diseases. Zn2+ plays a signalling role in modulating endothelial nitric oxide synthase and protects the endothelium against oxidative stress by up-regulation of glutathione synthesis. Excessive accumulation of Zn2+ in endothelial cells leads to apoptotic cell death resulting from dysregulation of glutathione and mitochondrial ATP synthesis, whereas zinc deficiency induces an inflammatory phenotype, associated with increased monocyte adhesion. Nuclear factor-E2-related factor 2 (NRF2) is a transcription factor known to target hundreds of different genes. Activation of NRF2 affects redox metabolism, autophagy, cell proliferation, remodelling of the extracellular matrix and wound healing. As a redox-inert metal ion, Zn has emerged as a biomarker in diagnosis and as a therapeutic approach for oxidative-related diseases due to its close link to NRF2 signalling. In non-vascular cell types, Zn has been shown to modify conformations of the NRF2 negative regulators Kelch-like ECH-associated Protein 1 (KEAP1) and glycogen synthase kinase 3β (GSK3β) and to promote degradation of BACH1, a transcriptional suppressor of select NRF2 genes. Zn can affect phosphorylation signalling, including mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinases and protein kinase C, which facilitate NRF2 phosphorylation and nuclear translocation. Notably, several NRF2-targeted proteins have been suggested to modify cellular Zn concentration via Zn exporters (ZnTs) and importers (ZIPs) and the Zn buffering protein metallothionein. This review summarises the cross-talk between reactive oxygen species, Zn and NRF2 in antioxidant responses of vascular cells against oxidative stress and hypoxia/reoxygenation.

E-Stilbenes: General Chemical and Biological Aspects, Potential Pharmacological Activity Based on the Nrf2 Pathway

Stilbenes are phytoalexins, and their biosynthesis can occur through a natural route (shikimate precursor) or an alternative route (in microorganism cultures). The latter is a metabolic engineering strategy to enhance production due to stilbenes recognized pharmacological and medicinal potential. It is believed that in the human body, these potential activities can be modulated by the regulation of the nuclear factor erythroid derived 2 (Nrf2), which increases the expression of antioxidant enzymes. Given this, our review aims to critically analyze evidence regarding E-stilbenes in human metabolism and the Nrf2 activation pathway, with an emphasis on inflammatory and oxidative stress aspects related to the pathophysiology of chronic and metabolic diseases. In this comprehensive literature review, it can be observed that despite the broad number of stilbenes, those most frequently explored in clinical trials and preclinical studies (in vitro and in vivo) were resveratrol, piceatannol, pterostilbene, polydatin, stilbestrol, and pinosylvin. In some cases, depending on the dose/concentration and chemical nature of the stilbene, it was possible to identify activation of the Nrf2 pathway. Furthermore, the use of some experimental models presented a challenge in comparing results. In view of the above, it can be suggested that E-stilbenes have a relationship with the Nrf2 pathway, whether directly or indirectly, through different biological pathways, and in different diseases or conditions that are mainly related to inflammation and oxidative stress.

Trimethylamine N-Oxide Improves Exercise Performance by Reducing Oxidative Stress through Activation of the Nrf2 Signaling Pathway

Trimethylamine N-oxide (TMAO) has attracted interest because of its association with cardiovascular disease and diabetes, and evidence for the beneficial effects of TMAO is accumulating. This study investigates the role of TMAO in improving exercise performance and elucidates the underlying molecular mechanisms. Using C2C12 cells, we established an oxidative stress model and administered TMAO treatment. Our results indicate that TMAO significantly protects myoblasts from oxidative stress-induced damage by increasing the expression of Nrf2, heme oxygenase-1 (HO-1), NAD(P)H dehydrogenase (NQO1), and catalase (CAT). In particular, suppression of Nrf2 resulted in a loss of the protective effects of TMAO and a significant decrease in the expression levels of Nrf2, HO-1, and NQO1. In addition, we evaluated the effects of TMAO in an exhaustive swimming test in mice. TMAO treatment significantly prolonged swimming endurance, increased glutathione and taurine levels, enhanced glutathione peroxidase activity, and increased the expression of Nrf2 and its downstream antioxidant genes, including HO-1, NQO1, and CAT, in skeletal muscle. These findings underscore the potential of TMAO to counteract exercise-induced oxidative stress. This research provides new insights into the ability of TMAO to alleviate exercise-induced oxidative stress via the Nrf2 signaling pathway, providing a valuable framework for the development of sports nutrition supplements aimed at mitigating oxidative stress.

D-ribose-L-cysteine exhibits restorative neurobehavioral functions through modulation of neurochemical activities and inhibition oxido-inflammatory perturbations in rats exposed to polychlorinated biphenyl

Polychlorinated biphenyl (PCB) is potentially harmful environmental toxicant causing cognitive decline with depressive features. PCB-induced behavioral deficits are associated with neurochemical dysfunctions, immune changes, and oxidative stress. This study investigated the neuroprotective effects of D-ribose-L-cysteine (DRLC), a neuroprotective precursor element of glutathione on PCB-induced neurobehavioral impairments. Following the initial 15 days of PCB (2 mg/kg) exposure to rats, DRLC (50 mg/kg) was given orally for an additional 15 days, from days 16 to 30. Animals were assessed for behavioral effect such as changes in locomotion, cognition, and depression. Oxidative/nitrergic stress markers; antioxidant regulatory proteins paraoxonase-1 (PON-1), heme oxygenase-1 (HO-1), nuclear factor erythroid 2-related factor 2 (Nfr2), NADPH oxidase-1 (NOX-1), NAD(P)H quinone oxidoreductase 1 (NQO1), and neuroinflammation (NF-kβ, and TNF-α); and neurochemical metabolizing enzymes (acetylcholinesterase (AChE), monoamine oxidase-A and -B (MAO-A, MAO-B)) were carried out. The PCB-induced decline in locomotion, cognitive performance, and depressive-like features were reversed by DRLC. More specifically, PCB-induced oxidative and nitrergic stress, typified by reduced levels GSH, CAT, and SOD, accompanied by elevated MDA and nitrite were attenuated by DRLC. Additionally, DRLC restored the neuroinflammatory milieu indicated by decreased NF-kβ and TNF-α levels toward normal. Hyperactivities of AChE, MAO-A, MAO-B, PON-1, and NOX-1 levels as well as Nfr2, NQO1, and PON-1 due to PCB exposure were mitigated by DLRC. Our results suggest DRLC as a prospective neurotherapeutic agent against PCB-induced neurobehavioral impairments such as cognitive deficit and depressive-like feature through antioxidative and anti-nitrergic stress, anti-neuroinflammation, inhibition of brain metabolizing enzymes, and normalization of neurochemical homeostasis.

Pharmacological activation of nuclear factor erythroid 2-related factor-2 prevents hyperglycemia-induced renal oxidative damage: Possible involvement of O-GlcNAcylation

Hyperglycemia is a major risk factor for kidney diseases. Oxidative stress, caused by reactive oxygen species, is a key factor in the development of kidney abnormalities related to hyperglycemia. The nuclear factor erythroid 2-related factor-2 (Nrf2) plays a crucial role in defending cells against oxidative stress by activating genes that produce antioxidants. L-sulforaphane (SFN), a drug that activates Nrf2, reduces damage caused by hyperglycemia. Hyperglycemic Wistar rats and HEK 293 cells maintained in hyperglycemic medium exhibited decreased Nrf2 nuclear translocation and reduced expression and activity of antioxidant enzymes. SFN treatment increased Nrf2 activity and reversed decreased renal function, oxidative stress and cell death associated with hyperglycemia. To investigate mechanisms involved in hyperglycemia-induced reduced Nrf2 activity, we addressed whether Nrf2 is modified by O-linked β-N-acetylglucosamine (O-GlcNAc), a post-translational modification that is fueled in hyperglycemic conditions. In vivo, hyperglycemia increased O-GlcNAc-modified Nrf2 expression. Increased O-GlcNAc levels, induced by pharmacological inhibition of OGA, decreased Nrf2 activity in HEK 293 cells. In conclusion, hyperglycemia reduces Nrf2 activity, promoting oxidative stress, cell apoptosis and structural and functional renal damage. Pharmacological treatment with SFN attenuates renal injury. O-GlcNAcylation negatively modulates Nrf2 activity and represents a potential mechanism leading to oxidative stress and renal damage in hyperglycemic conditions.

SiONx Coating Regulates Mesenchymal Stem Cell Antioxidant Capacity via Nuclear Erythroid Factor 2 Activity under Toxic Oxidative Stress Conditions

Healing in compromised and complicated bone defects is often prolonged and delayed due to the lack of bioactivity of the fixation device, secondary infections, and associated oxidative stress. Here, we propose amorphous silicon oxynitride (SiONx) as a coating for the fixation devices to improve both bioactivity and bacteriostatic activity and reduce oxidative stress. We aimed to study the effect of increasing the N/O ratio in the SiONx to fine-tune the cellular activity and the antioxidant effect via the NRF2 pathway under oxidative stress conditions. The in vitro studies involved using human mesenchymal stem cells (MSCs) to examine the effect of SiONx coatings on osteogenesis with and without toxic oxidative stress. Additionally, bacterial growth on SiONx surfaces was studied using methicillin-resistant Staphylococcus aureus (MRSA) colonies. NRF2 siRNA transfection was performed on the hMSCs (NRF2-KD) to study the antioxidant response to silicon ions. The SiONx implant surfaces showed a >4-fold decrease in bacterial growth vs. bare titanium as a control. Increasing the N/O ratio in the SiONx implants increased the alkaline phosphatase activity >1.5 times, and the other osteogenic markers (osteocalcin, RUNX2, and Osterix) were increased >2-fold under normal conditions. Increasing the N/O ratio in SiONx enhanced the protective effects and improved cell viability against toxic oxidative stress conditions. There was a significant increase in osteocalcin activity compared to the uncoated group, along with increased antioxidant activity under oxidative stress conditions. In NRF2-KD cells, there was a stunted effect on the upregulation of antioxidant markers by silicon ions, indicating a role for NRF2. In conclusion, the SiONx coatings studied here displayed bacteriostatic properties. These materials promoted osteogenic markers under toxic oxidative stress conditions while also enhancing antioxidant NRF2 activity. These results indicate the potential of SiONx coatings to induce in vivo bone regeneration in a challenging oxidative stress environment.

Cardioprotective Effects of Hydrogen Sulfide and Its Potential Therapeutic Implications in the Amelioration of Duchenne Muscular Dystrophy Cardiomyopathy

Hydrogen sulfide (H2S) belongs to the family of gasotransmitters and can modulate a myriad of biological signaling pathways. Among others, its cardioprotective effects, through antioxidant, anti-inflammatory, anti-fibrotic, and proangiogenic activities, are well-documented in experimental studies. Cardiorespiratory failure, predominantly cardiomyopathy, is a life-threatening complication that is the number one cause of death in patients with Duchenne muscular dystrophy (DMD). Although recent data suggest the role of H2S in ameliorating muscle wasting in murine and Caenorhabditis elegans models of DMD, possible cardioprotective effects have not yet been addressed. In this review, we summarize the current understanding of the role of H2S in animal models of cardiac dysfunctions and cardiac cells. We highlight that DMD may be amenable to H2S supplementation, and we suggest H2S as a possible factor regulating DMD-associated cardiomyopathy.

Neuroprotection during Thrombectomy for Acute Ischemic Stroke: A Review of Future Therapies

Stroke is a major cause of death and disability worldwide. Endovascular thrombectomy has been impactful in decreasing mortality. However, many clinical results continue to show suboptimal functional outcomes despite high recanalization rates. This gap in recanalization and symptomatic improvement suggests a need for adjunctive therapies in post-thrombectomy care. With greater insight into ischemia-reperfusion injury, recent preclinical testing of neuroprotective agents has shifted towards preventing oxidative stress through upregulation of antioxidants and downstream effectors, with positive results. Advances in multiple neuroprotective therapies, including uric acid, activated protein C, nerinetide, otaplimastat, imatinib, verapamil, butylphthalide, edaravone, nelonemdaz, ApTOLL, regional hypothermia, remote ischemic conditioning, normobaric oxygen, and especially nuclear factor erythroid 2-related factor 2, have promising evidence for improving stroke care. Sedation and blood pressure management in endovascular thrombectomy also play crucial roles in improved stroke outcomes. A hand-in-hand approach with both endovascular therapy and neuroprotection may be the key to targeting disability due to stroke.

NRF2 connects Src tyrosine kinase to ferroptosis resistance in glioblastoma

Glioblastoma is a severe brain tumor characterized by an extremely poor survival rate of patients. Glioblastoma cancer cells escape to standard therapeutic protocols consisting of a combination of ionizing radiation and temozolomide alkylating drugs that trigger DNA damage by rewiring of signaling pathways. In recent years, the up-regulation of factors that counteract ferroptosis has been highlighted as a major driver of cancer resistance to ionizing radiation, although the molecular connection between the activation of oncogenic signaling and the modulation of ferroptosis has not been clarified yet. Here, we provide the first evidence for a molecular connection between the constitutive activation of tyrosine kinases and resistance to ferroptosis. Src tyrosine kinase, a central hub on which deregulated receptor tyrosine kinase signaling converge in cancer, leads to the stabilization and activation of NRF2 pathway, thus promoting resistance to ionizing radiation-induced ferroptosis. These data suggest that the up-regulation of the Src-NRF2 axis may represent a vulnerability for combined strategies that, by targeting ferroptosis resistance, enhance radiation sensitivity in glioblastoma.

Mitochondria-targeted cerium vanadate nanozyme suppressed hypoxia-ischemia injury in neonatal mice via intranasal administration

Oxidative stress is a major obstacle for neurological functional recovery after hypoxia-ischemia (HI) brain damage. Nanozymes with robust anti-oxidative stress properties offer a therapeutic option for HI injury. However, insufficiency of nanozyme accumulation in the HI brain by noninvasive administration hinders their application. Herein, we reported a cerium vanadate (CeVO4) nanozyme to realize a noninvasive therapy for HI brain in neonatal mice by targeting brain neuron mitochondria. CeVO4 nanozyme with superoxide dismutase activity mainly co-located with neuronal mitochondria 1 h after administration. Pre- and post-HI administrations of CeVO4 nanozyme were able to attenuate acute brain injury, by inhibiting caspase-3 activation, microglia activation, and proinflammation cytokine production in the lesioned cortex 2 d after HI injury. Moreover, CeVO4 nanozyme administration led to short- and long-term functional recovery following HI insult without any potential toxicities in peripheral organs of mice even after prolonged delivery for 4 weeks. These beneficial effects of CeVO4 nanozyme were associated with suppressed oxidative stress and up-regulated nuclear factor erythroid-2-related factor 2 (Nrf2) expression. Finally, we found that Nrf2 inhibition with ML385 abolished the protective effects of CeVO4 nanozyme on HI injury. Collectively, this strategy may provide an applicative perspective for CeVO4 nanozyme therapy in HI brain damage via noninvasive delivery.

Physiological and molecular predictors of cycling sprint performance

The study aimed to identify novel muscle phenotypic factors that could determine sprint performance using linear regression models including the lean mass of the lower extremities (LLM), myosin heavy chain composition (MHC), and proteins and enzymes implicated in glycolytic and aerobic energy generation (citrate synthase, OXPHOS proteins), oxygen transport and diffusion (myoglobin), ROS sensing (Nrf2/Keap1), antioxidant enzymes, and proteins implicated in calcium handling. For this purpose, body composition (dual-energy X-ray absorptiometry) and sprint performance (isokinetic 30-s Wingate test: peak and mean power output, Wpeak and Wmean ) were measured in young physically active adults (51 males and 10 females), from which a resting muscle biopsy was obtained from the musculus vastus lateralis. Although females had a higher percentage of MHC I, SERCA2, pSer16 /Thr17 -phospholamban, and Calsequestrin 2 protein expressions (all p < 0.05), and 18.4% lower phosphofructokinase 1 protein expression than males (p < 0.05), both sexes had similar sprint performance when it was normalized to body weight or LLM. Multiple regression analysis showed that Wpeak could be predicted from LLM, SDHB, Keap1, and MHC II % (R 2  = 0.62, p < 0.001), each variable contributing to explain 46.4%, 6.3%, 4.4%, and 4.3% of the variance in Wpeak , respectively. LLM and MHC II % explained 67.5% and 2.1% of the variance in Wmean , respectively (R 2  = 0.70, p < 0.001). The present investigation shows that SDHB and Keap1, in addition to MHC II %, are relevant determinants of peak power output during sprinting.

Predominant factors influencing reactive oxygen species in cancer stem cells

Reactive oxygen species (ROS) and its related signaling pathways and regulating molecules play a major role in the growth and development of cancer stem cells. The concept of ROS and cancer stem cells (CSCs) has been gaining much attention since the past decade and the evidence show that these CSCs possess robust self-renewal and tumorigenic potential and are resistant to conventional chemo- and radiotherapy and believed to be responsible for tumor progression, metastasis, and recurrence. It seems reasonable to say that cancer can be cured only if the CSCs are eradicated. ROS are Janus-faced molecules that can regulate cellular physiology as well as induce cytotoxicity, depending on the magnitude, duration, and site of generation. Unlike normal cancer cells, CSCs expel ROS efficiently by upregulating ROS scavengers. This unique redox regulation in CSCs protects them from ROS-mediated cell death and nullifies the effect of radiation, leading to chemoresistance and radioresistance. However, how these CSCs control ROS production by scavenging free radicals and how they maintain low levels of ROS is a challenging to understand and these attributes make CSCs as prime therapeutic targets. Here, we summarize the mechanisms of redox regulation in CSCs, with a focus on therapy resistance, its various pathways and microRNAs regulation, and the potential therapeutic implications of manipulating the ROS levels to eradicate CSCs. A better understanding of these molecules, their interactions in the CSCs may help us to adopt proper control and treatment measures.

Flavonoids Regulate Redox-Responsive Transcription Factors in Glioblastoma and Microglia

The tumor microenvironment (TME) has emerged as a valuable therapeutic target in glioblastoma (GBM), as it promotes tumorigenesis via an increased production of reactive oxygen species (ROS). Immune cells such as microglia accumulate near the tumor and its hypoxic core, fostering tumor proliferation and angiogenesis. In this study, we explored the therapeutic potential of natural polyphenols with antioxidant and anti-inflammatory properties. Notably, flavonoids, including fisetin and quercetin, can protect non-cancerous cells while eliminating transformed cells (2D cultures and 3D tumoroids). We tested the hypothesis that fisetin and quercetin are modulators of redox-responsive transcription factors, for which subcellular location plays a critical role. To investigate the sites of interaction between natural compounds and stress-responsive transcription factors, we combined molecular docking with experimental methods employing proximity ligation assays. Our findings reveal that fisetin decreased cytosolic acetylated high mobility group box 1 (acHMGB1) and increased transcription factor EB (TFEB) abundance in microglia but not in GBM. Moreover, our results suggest that the most powerful modulator of the Nrf2-KEAP1 complex is fisetin. This finding is in line with molecular modeling and calculated binding properties between fisetin and Nrf2-KEAP1, which indicated more sites of interactions and stronger binding affinities than quercetin.

Overcoming the compensatory increase in NRF2 induced by NPL4 inhibition enhances disulfiram/copper-induced oxidative stress and ferroptosis in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney cancer, and it appears to be highly susceptible to ferroptosis. Disulfiram, an alcoholism drug, has been shown to have anticancer properties in various studies, including those on RCC. However, the mechanism of the anticancer effect of disulfiram/copper on RCC remains unclear. In this study, we investigated the impact of disulfiram/copper on RCC treatment using both RCC cells and mouse subcutaneous tumor models. Our findings demonstrate that disulfiram/copper treatment reduced the viability of RCC cells, inhibited their invasion and migration, and disrupted mitochondrial homeostasis, ultimately leading to oxidative stress and ferroptosis. Mechanistically, disulfiram/copper treatment prolonged the half-life of NRF2 and reduced its degradation, but had no effect on transcription, indicating that the disulfiram/copper-induced increase in NRF2 was not related to transcription. Furthermore, we observed that disulfiram/copper treatment reduced the expression of NPL4, a ubiquitin protein-proteasome system involved in NRF2 degradation, while overexpression of NPL4 reversed NRF2 levels and enhanced disulfiram/copper-induced oxidative stress and ferroptosis. These results suggest that overcoming the compensatory increase in NRF2 induced by NPL4 inhibition enhances disulfiram/copper-induced oxidative stress and ferroptosis in RCC. In addition, our in vivo experiments revealed that disulfiram/copper synergized with sorafenib to inhibit the growth of RCC cells and induce ferroptosis. In conclusion, our study sheds light on a possible mechanism for disulfiram/copper treatment in RCC and provides a potential synergistic strategy to overcome sorafenib resistance.

Nrf2 for a key member of redox regulation: A novel insight against myocardial ischemia and reperfusion injuries

Nuclear factor erythroid-2 related factor 2 (Nrf2), a nuclear transcription factor, modulates genes responsible for antioxidant responses against toxic and oxidative stress to maintain redox homeostasis and participates in varieties of cellular processes such as metabolism and inflammation during myocardial ischemia and reperfusion injuries (MIRI). The accumulation of reactive oxygen species (ROS) from damaged mitochondria, xanthine oxidase, NADPH oxidases, and inflammation contributes to depraved myocardial ischemia and reperfusion injuries. Considering that Nrf2 played crucial roles in antagonizing oxidative stress, it is reasonable to delve into the up or down-regulated molecular mechanisms of Nrf2 in the progression of MIRI to provide the possibility of new therapeutic medicine targeting Nrf2 in cardiovascular diseases. This review systematically describes the generation of ROS, the regulatory metabolisms of Nrf2 as well as several natural or synthetic compounds activating Nrf2 during MIRI, which might provide novel insights for the anti-oxidative stress and original ideas targeting Nrf2 for the prevention and treatment in cardiovascular diseases.

Comparative analysis of the molecular and physiological consequences of constitutive SKN-1 activation

Molecular homeostats play essential roles across all levels of biological organization to ensure a return to normal function after responding to abnormal internal and environmental events. SKN-1 is an evolutionarily conserved cytoprotective transcription factor that is integral for the maintenance of cellular homeostasis upon exposure to a variety of stress conditions. Despite the essentiality of turning on SKN-1/NRF2 in response to exogenous and endogenous stress, animals with chronic activation of SKN-1 display premature loss of health with age, and ultimately, diminished lifespan. Previous genetic models of constitutive SKN-1 activation include gain-of-function alleles of skn-1 and loss-of-function alleles of wdr-23 that impede the turnover of SKN-1 by the ubiquitin proteasome. Here, we define a novel gain-of-function mutation in the xrep-4 locus that results in constitutive activation of SKN-1 in the absence of stress. Although each of these genetic mutations results in continuously unregulated transcriptional output from SKN-1, the physiological consequences of each model on development, stress resistance, reproduction, lipid homeostasis, and lifespan are distinct. Here, we provide a comprehensive assessment of the differential healthspan impacts across multiple models of constitutive SKN-1 activation. Although our results reveal the universal need to reign in the uncontrolled activity of cytoprotective transcription factors, we also define the unique signatures of each model of constitutive SKN-1 activation, which provides innovative solutions for the design of molecular "off-switches" of unregulated transcriptional homeostats.

PM2.5 exposure increases dry eye disease risks through corneal epithelial inflammation and mitochondrial dysfunctions

Dry eye disease (DED) is the most common disease affecting vision and quality of life. PM2.5 was a potential risk of DED. Herein, we conducted animal exposure and cell-based studies to evaluate the pathogenic effect of PM2.5 exposure on the ocular surface and DED etiological mechanisms. C57 mice were exposed to filtered air and PM2.5 aerosol. We assessed health conditions and inflammation of the ocular surface by corneal fluorescein staining and immunohistochemistry. In parallel, cultured human corneal epithelial cells (HCETs) were treated with PM2.5, followed by characterization of cell viability, intracellular ATP level, mitochondrial activities, and expression level of DED relevant mRNA and proteins. In mice, PM2.5 exposure induced severe superficial punctate keratopathy and inflammation in their cornea. In HCETs, cell proliferation and ROS generation followed dose-response and time-dependent manner; meanwhile, mitochondrial ROS (mtROS) level increased and mitochondrial membrane potential (MMP) level decreased. Inflammation cascade was triggered even after short-term exposure. The reduction of ATP production was alleviated with Nrf2 overexpression, NF-κB P65 knockdown, or ROS clearance. Nrf2 overexpression and P65 knockdown reduced inflammatory reaction through decreasing expression of P65 and increasing of Nrf2, respectively. They partly alleviated changes of ROS/mtROS/MMP. This research proved that PM2.5 would cause DED-related inflammation reaction on corneal epithelial cells and further explored its mechanism: ROS from mitochondrial dysfunctions of corneal epithelial cells after PM2.5 exposure partly inhibited the expression of anti-inflammatory protein Nrf2 led the activation of inflammatory protein P65 and its downstream molecules, which finally caused inflammation reaction.

4-methoxycinnamyl p-coumarate reduces neuroinflammation by blocking NF-κB, MAPK, and Akt/GSK-3β pathways and enhancing Nrf2/HO-1 signaling cascade in microglial cells

The active compound, 4-methoxycinnamyl p-coumarate (MCC), derived from the rhizome of Etlingera pavieana (Pierre ex Gagnep) R.M.Sm., has been shown to exert anti-inflammatory effects in several inflammatory models. However, its effects on microglial cells remain elusive. In the current study, we aimed to investigate the anti-neuroinflammatory activities of MCC and determine the potential mechanisms underlying its action on lipopolysaccharide (LPS)-induced BV2 microglial cells. Our results revealed that MCC significantly reduced the secretion of nitric oxide (NO) and prostaglandin E2, concomitantly inhibiting the expression levels of inducible NO synthase and cyclooxygenase-2 mRNA and proteins. Additionally, MCC effectively decreased the production of reactive oxygen species in LPS-induced BV2 microglial cells. MCC also attenuates the activation of NF-κB by suppressing the phosphorylation of IκBα and NF-κB p65 subunits and by blocking the nuclear translocation of NF-κB p65 subunits. Furthermore, MCC significantly reduced the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β). In addition, MCC markedly increased the expression of heme oxygenase-1 (HO-1) by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Collectively, our findings suggest that the anti-inflammatory activities of MCC could be attributed to its ability to suppress the activation of NF-κB, MAPK, and Akt/GSK-3β while enhancing that of Nrf2-mediated HO-1. Accordingly, MCC has promising therapeutic potential to treat neuroinflammation-related diseases.

Diabetes mellitus: Classification, mediators, and complications; A gate to identify potential targets for the development of new effective treatments

Nowadays, diabetes mellitus has emerged as a significant global public health concern with a remarkable increase in its prevalence. This review article focuses on the definition of diabetes mellitus and its classification into different types, including type 1 diabetes (idiopathic and fulminant), type 2 diabetes, gestational diabetes, hybrid forms, slowly evolving immune-mediated diabetes, ketosis-prone type 2 diabetes, and other special types. Diagnostic criteria for diabetes mellitus are also discussed. The role of inflammation in both type 1 and type 2 diabetes is explored, along with the mediators and potential anti-inflammatory treatments. Furthermore, the involvement of various organs in diabetes mellitus is highlighted, such as the role of adipose tissue and obesity, gut microbiota, and pancreatic β-cells. The manifestation of pancreatic Langerhans β-cell islet inflammation, oxidative stress, and impaired insulin production and secretion are addressed. Additionally, the impact of diabetes mellitus on liver cirrhosis, acute kidney injury, immune system complications, and other diabetic complications like retinopathy and neuropathy is examined. Therefore, further research is required to enhance diagnosis, prevent chronic complications, and identify potential therapeutic targets for the management of diabetes mellitus and its associated dysfunctions.

Antioxidant enzymes and Nrf2/Keap1 in human skeletal muscle: Influence of age, sex, adiposity and aerobic fitness

Ageing, a sedentary lifestyle, and obesity are associated with increased oxidative stress, while regular exercise is associated with an increased antioxidant capacity in trained skeletal muscles. Whether a higher aerobic fitness is associated with increased expression of antioxidant enzymes and their regulatory factors in skeletal muscle remains unknown. Although oestrogens could promote a higher antioxidant capacity in females, it remains unknown whether a sex dimorphism exists in humans regarding the antioxidant capacity of skeletal muscle. Thus, the aim was to determine the protein expression levels of the antioxidant enzymes SOD1, SOD2, catalase and glutathione reductase (GR) and their regulatory factors Nrf2 and Keap1 in 189 volunteers (120 males and 69 females) to establish whether sex differences exist and how age, VO2max and adiposity influence these. For this purpose, vastus lateralis muscle biopsies were obtained in all participants under resting and unstressed conditions. No significant sex differences in Nrf2, Keap1, SOD1, SOD2, catalase and GR protein expression levels were observed after accounting for VO2max, age and adiposity differences. Multiple regression analysis indicates that the VO2max in mL.kg LLM-1.min-1can be predicted from the levels of SOD2, Total Nrf2 and Keap1 (R = 0.58, P < 0.001), with SOD2 being the main predictor explaining 28 % of variance in VO2max, while Nrf2 and Keap1 explained each around 3 % of the variance. SOD1 protein expression increased with ageing in the whole group after accounting for differences in VO2max and body fat percentage. Overweight and obesity were associated with increased pSer40-Nrf2, pSer40-Nrf2/Total Nrf2 ratio and SOD1 protein expression levels after accounting for differences in age and VO2max. Overall, at the population level, higher aerobic fitness is associated with increased basal expression of muscle antioxidant enzymes, which may explain some of the benefits of regular exercise.

Toxic dinoflagellate Karenia mikimotoi induces apoptosis in Neuro-2a cells through an oxidative stress-mediated mitochondrial pathway

The dinoflagellate Karenia mikimotoi is a toxic bloom-forming species that threatens aquaculture and public health worldwide. Previous studies showed that K. mikimotoi induces neurotoxicity; however, the underlying mechanism is poorly understood. In this study, three neural cell lines were used to investigate the potential neurotoxicity of K. mikimotoi. The tested cells were exposed to a ruptured cell solution (RCS) of K. mikimotoi at different concentrations (0.5 × 105, 1.0 × 105, 2.0 × 105, 4.0 × 105, and 6 × 105 cells mL-1) for 24 h, and the RCS decreased cell viabilities and promoted Neuro-2a (N2A) cell apoptosis in a dose-dependent manner. The underlying mechanism was further investigated in N2A cells. At the biochemical level, the RCS stimulated reactive oxygen species (ROS) and malondialdehyde (MDA) formation, decreased SOD activity, and reduced mitochondrial membrane potential (MMP). At the gene level, the moderate RCS treatment (2.0 × 105 cells mL-1) upregulated antioxidant response genes (e.g., nrf-2, HO-1, NQO-1, and cat) to alleviate RCS-induced oxidative stress, while the high RCS treatment (4.0 × 105 cells mL-1) downregulated these genes, thereby aggravating oxidative stress. Meanwhile, apoptosis-related genes (e.g., p53, caspase 3, and bax2) were significantly upregulated and the anti-apoptotic gene bcl2 was suppressed after RCS treatment. Western blotting results for Caspase 3, Bax2 and Bcl2 were consistent with the mRNA trends. These results revealed that K. mikimotoi RCS can induce neural cell apoptosis via the oxidative stress-mediated mitochondrial pathway, providing novel insights into the neurotoxicity of K. mikimotoi.

Antioxidant effect of lactic acid bacteria in human bronchial epithelial cells exposed to cigarette smoke

AIMS

Chronic lung diseases are a major and increasing global health problem, commonly caused by cigarette smoke. We aimed to explore the antioxidant effects of lactic acid bacteria (LAB) against cigarette smoke in bronchial epithelial cells.

METHODS AND RESULTS

The antioxidant effects of 21 heat-killed (HK) LAB strains were tested in cigarette smoke-stimulated BEAS-2B cells and 3-D bronchospheres organoids. We showed that HK Lactiplantibacillus plantarum BGPKM22 possesses antioxidant activity against cigarette smoke, resistance to hydrogen peroxide, and free radical neutralizing activity. We demonstrated that HK BGPKM22 inhibited cigarette smoke-induced expression of the Aryl hydrocarbon receptor (AhR) and Nuclear factor erythroid 2 related factor 2 (Nrf2) genes. The cell-free supernatant (SN) of BGPKM22 fully confirmed the effects of HK BGPKM22.

CONCLUSIONS

For the first time, we revealed that HK and SN of Lactip. plantarum BGPKM22 possess antioxidant activity and modulate AhR and Nrf2 gene expression in bronchial epithelial cells exposed to cigarette smoke.

Immunoediting of KEAP1-NRF2 mutant tumours is required to circumvent NRF2-mediated immune surveillance

In human cancer, activating mutations in the KEAP1-NRF2 pathway are frequently observed, and positively selected for, as they confer the cytoprotective functions of the transcription factor NRF2 on the cancer cells. This results in the development of aggressive tumours which are resistant to treatment with chemotherapeutic compounds. Recent clinical developments have also revealed that NRF2-activated cancers are similarly resistant to immune checkpoint inhibitor drugs. As the mechanism of action of these immune modulating therapies is tangential to the classical cytoprotective function of NRF2, it is unclear how aberrant NRF2 activity could impact the anti-cancer functionality of the immune system. In this context, we found that in human cancer, NRF2-activated cells are highly immunoedited, which allows the cancer cells to escape immune surveillance and develop into malignant tumours. This immunoediting takes the form of reduced antigen presentation by the MHC-I complex, coupled with reduced expression of activating ligands for NK cells. Together, these modifications to the immunogenicity of NRF2-activated cancers inhibit immune effector cell infiltration and engagement, and contribute to the formation of the immunologically cold tumour microenvironment which is a characteristic feature of NRF2-activated cancers.

Sulforaphane rewires central metabolism to support antioxidant response and achieve glucose homeostasis

Cruciferous-rich diets, particularly broccoli, have been associated with reduced risk of developing cancers of various sites, cardiovascular disease and type-2 diabetes. Sulforaphane (SF), a sulfur-containing broccoli-derived metabolite, has been identified as the major bioactive compound mediating these health benefits. Sulforaphane is a potent dietary activator of the transcription factor Nuclear factor erythroid-like 2 (NRF2), the master regulator of antioxidant cell capacity responsible for inducing cytoprotective genes, but its role in glucose homeostasis remains unclear. In this study, we set to test the hypothesis that SF regulates glucose metabolism and ameliorates glucose overload and its resulting oxidative stress by inducing NRF2 in human hepatoma HepG2 cells. HepG2 cells were exposed to varying glucose concentrations: basal (5.5 mM) and high glucose (25 mM), in the presence of physiological concentrations of SF (10 μM). SF upregulated the expression of glutathione (GSH) biosynthetic genes and significantly increased levels of reduced GSH. Labelled glucose and glutamine experiments to measure metabolic fluxes identified that SF increased intracellular utilisation of glycine and glutamate by redirecting the latter away from the TCA cycle and increased the import of cysteine from the media, likely to support glutathione synthesis. Furthermore, SF altered pathways generating NADPH, the necessary cofactor for oxidoreductase reactions, namely pentose phosphate pathway and 1C-metabolism, leading to the redirection of glucose away from glycolysis and towards PPP and of methionine towards methylation substrates. Finally, transcriptomic and targeted metabolomics LC-MS analysis of NRF2-KD HepG2 cells generated using CRISPR-Cas9 genome editing revealed that the above metabolic effects are mediated through NRF2. These results suggest that the antioxidant properties of cruciferous diets are intricately connected to their metabolic benefits.