The Nrf2 system as a potential target for the development of indirect antioxidants

Flavonoids from Polypodium hastatum as neuroprotective agents attenuate cerebral ischemia/reperfusion injury in vitro and in vivo via activating Nrf2

OBJECTIVES

Cerebral ischemic stroke is a leading cause of death worldwide. Though timely reperfusion reduces the infarction size, it exacerbates neuronal apoptosis due to oxidative stress. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor regulating the expression of antioxidant enzymes. Activating Nrf2 gives a therapeutic approach to ischemic stroke.

METHODS

Herein we explored flavonoids identified from Polypodium hastatum as Nrf2 activators and their protective effects on PC12 cells injured by oxygen and glucose deprivation/restoration (OGD/R) as well as middle cerebral artery occlusion (MCAO) mice.

RESULTS

The results showed among these flavonoids, AAKR significantly improved the survival of PC12 cells induced by OGD/R and activated Nrf2 in a Keap1-dependent manner. Further investigations have disclosed AAKR attenuated oxidative stress, mitochondrial dysfunction and following apoptosis resulting from OGD/R. Meanwhile, activation of Nrf2 by AAKR was involved in the protective effects. Finally, it was found that AAKR could protect MCAO mice brains against ischemia/reperfusion injury via activating Nrf2.

DISCUSSION

This investigation could provide lead compounds for the discovery of novel Nrf2 activators targeting ischemia/reperfusion injury.

Nrf2 protects against oxidative damage induced by hemoglobin in the liver of grass carp (Ctenopharyngodon idella)

Hemoglobin (Hb) releases during hemorrhaging and causes oxidative damage, further exacerbates the development of multiple diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates cellular defenses against toxic and oxidative challenges. However, the regulation mechanism of Nrf2 in Hb-induced oxidative stress remains unclear in teleost. To accomplish this goal, a hemolysis model was established by injecting grass carp with phenylalanine (PHZ), and the immunofluorescence analysis (IFA) and hematoxylin and eosin (H&E) staining revealed that PHZ-induced hemolysis caused Hb accumulation and hepatic vacuolization, resulted in tissue damage. Prussian blue, Sirius red, and Masson staining results revealed significant iron deposition and extensive collagen fiber accumulation in the liver. IFA and immunohistochemical analyses demonstrated that PHZ-induced hemolysis markedly increased the production of reactive oxygen species (ROS), malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE). The quantitative real-time PCR (qRT-PCR) analysis data revealed that the PHZ-induced hemolysis also significantly upregulated the expression of antioxidant-related genes through activation of the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/Nrf2 signaling pathway. To further explore the molecule regulation mechanism of PHZ-induced hemolysis, the RNA-seq analysis was performed, and the data revealed that the AMPK/Nrf2 and multiple programmed cell death pathways, including ferroptosis, autophagy, apoptosis, and necroptosis in PHZ injection groups were significant upregulated. In vitro, the hemin supplementation activated the expression of target genes in the AMPK/Nrf2 pathway detected by qRT-PCR. To further verify the regulation function of Nrf2, an Nrf2 activator (4OI) was supplemented, and the flow cytometer analysis results suggested that the Hb-induced cell damage was significantly attenuated. However, the supplementary of ML385 down-regulated the AMPK/Nrf2 pathway and aggravated the hemin induced cell death. In conclusion, these findings highlight the critical regulatory role of the AMPK/Nrf2 signaling pathway in protecting against Hb-induced oxidative damage in the liver of grass carp.

Nanoscale covalent organic framework-mediated pyroelectrocatalytic activation of immunogenic cell death for potent immunotherapy

The conventional molecular immunogenic cell death (ICD) inducers suffer from poor biocompatibility and unsatisfactory efficacy. Here, a biocompatible nanosized covalent organic framework (nCOF)-based pyroelectric catalyst (denoted as TPAD-COF NPs) is designed for pyroelectric catalysis-activated in situ immunotherapy. TPAD-COF NPs confine organic pyroelectric molecules to rigid TPAD-COF NPs to substantially reduce aggregation and enhance biocompatibility, thus improving pyroelectrocatalytic efficiency. After tumor internalization, TPAD-COF NPs facilitate photothermal tumor ablation under near-infrared (NIR) laser exposure, resulting in effective ICD induction. In addition, TPAD-COF NPs effectively catalyze the conversion of temperature changes to pyroelectric changes, which subsequently react with adjacent O2 to generate reactive oxygen species, thus triggering robust ICD activation. In vivo evaluation using mouse models confirmed that TPAD-COF NPs evidently inhibited the proliferation of primary and distant tumors and prevented lung metastasis under NIR laser illumination. Therefore, this study opens an avenue for designing nCOF-based catalysts for pyroelectric catalysis-activated in situ immunotherapy.

Esculin, a Coumarin Glucoside Prevents Fluoride-Induced Oxidative Stress and Cardiotoxicity in Zebrafish Larvae

Fluoride (F-) is a major groundwater contaminant spread across the world. In excess concentrations, F- can be detrimental to living beings. F- exposure is linked to cellular redox dyshomeostasis, leading to oxidative stress-mediated pathologies including heart dysfunction. Due to its potent antioxidant properties, various phytochemicals are found to alleviate the symptoms of F- toxicity. Hence, we explore the protective effect of esculin (Esc), a coumarin glucoside on F--induced oxidative stress and cardiotoxicity in zebrafish larvae. The experimental groups consisted of NaF (50 ppm) and Esc (100 μM) groups treated alone and in combination with a control group for 6 h. The groups were maintained till 78 hpf after which the level of oxidants (ROS, LPO, and PCC) and antioxidants (GST, GSH, GPx, SOD, and CAT) were assessed. The results revealed that Esc pretreatment restored the depleted antioxidant markers and reduced the levels of oxidant in the Esc+NaF group, exhibiting its antioxidant potential. In addition, analyses of the heartbeat rate and hemoglobin integrity using o-Dianisidine staining were conducted in the control and experimental groups. Esc treatment prevents F- induced cardiac changes including tachycardia and altered blood flow. Further, the mRNA expression level of antioxidant genes (nrf2, gstp1, hmox1a, prdx1, and nqo1) and cardiac developmental genes (bmp2b, nkx2.5, myh6, and myl7) confirmed that Esc acts as a potent free radical scavenger and antioxidant defense enhancer, protecting zebrafish larvae from NaF-induced oxidative stress and heart dysfunction.

Transcriptional and post-transcriptional regulation of CARMN and its anti-tumor function in cervical cancer through autophagic flux blockade and MAPK cascade inhibition

BACKGROUND

LncRNAs play essential roles in multiple tumors. However, research on genome-wide lncRNA alterations and their functions in cervical cancer (CC) is limited. This study aims to explore key lncRNAs in CC progression and uncover the molecular mechanisms involved in the development of CC.

METHODS

In this study, we analyzed 30 tissues from CC, cervical intraepithelial neoplasia (CIN), and normal (NOR) using transcriptome sequencing and weighted gene co-expression network analysis to establish gene modules related to the NOR-CIN-CC transition. Machine learning diagnostic models were employed to investigate the role of lncRNAs in this transition. Molecular biological experiments were conducted to elucidate the potential mechanisms of CARMN in CC, with a particular focus on its transcriptional and post-transcriptional regulation of abnormal expression in CC.

RESULTS

CARMN was identified as a hub gene in two modules significantly associated with the NOR-CIN-CC transition. Analysis using ten machine learning models confirmed its critical role in this progression. The results of RNA-seq, qPCR and RNAScope performed in another cohort of 83 cervical tissues all showed that CARMN was significantly downregulated in CC. CARMN significantly enhanced the interaction between Keap1 and Nrf2, leading to increased ROS levels. The elevated ROS levels suppressed the Akt/mTOR signaling pathway, leading to autophagy arrest via autophagic flux blockade. Additionally, CARMN interacted with TFAP2α to repress MAPK13 transcription, further inhibiting the MAPK cascade. A promoter SNP (rs12517403) was found to increase CC risk (OR = 1.34, 95% CI = 1.11-1.61) and reduce CARMN expression by decreasing SP1 binding. Furthermore, the RNA binding proteins that could modulate CARMN RNA stability were also determined using RNA-pulldown assay. The results demonstrated that YBX1, a component of the coding region instability determinant (CRD)-mediated mRNA stabilization complex, promoted CARMN RNA stability. DHX9, another component of complex, acted as a scaffold to bridge YBX1 and CARMN.

CONCLUSIONS

CARMN exerts an anti-cancer effect in CC progression by inhibiting the Akt-mTOR and MAPK signaling pathways. rs12517403 and the YBX1/DHX9 complex are key mechanisms influencing its transcription and stability in CC cells. CARMN represents a promising biomarker for CC diagnosis and therapeutic target.

The NRF-2/HO-1 Signaling Pathway: A Promising Therapeutic Target for Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a progressive liver disorder with a rising prevalence. It begins with lipid accumulation in hepatocytes and gradually progresses to Metabolic-associated steatohepatitis (MASH), fibrosis, cirrhosis, and potentially hepatocellular carcinoma (HCC). The pathophysiology of MASLD is complex and involves multiple factors, with oxidative stress playing a crucial role. Oxidative stress drives the progression of MASLD by causing cellular damage, inflammatory responses, and fibrosis, making it a key pathogenic mechanism. The Nuclear Factor Erythroid 2-Related Factor 2 / Heme Oxygenase-1 (Nrf2/HO-1) signaling axis provides robust multi-organ protection against a spectrum of endogenous and exogenous insults, particularly oxidative stress. It plays a pivotal role in mediating antioxidant, anti-inflammatory, and anti-apoptotic responses. Many studies indicate that activating the Nrf2/HO-1 signaling pathway can significantly mitigate the progression of MASLD. This article examines the role of the Nrf2/HO-1 signaling pathway in MASLD and highlights natural compounds that protect against MASLD by targeting Nrf2/HO-1 activation. The findings indicate that the Nrf2/HO-1 signaling pathway holds great promise as a therapeutic target for MASLD.

In Vitro Screening of Trehalose Synbiotics and Their Effects on Early-Lactating Females and Offspring Mice

Activities such as childbirth and breastfeeding can cause severe oxidative stress and inflammatory damage to the mother during early lactation, and can affect animal milk production, and the growth and development of offspring. Trehalose alleviates damage to the body by endowing it with stress resistance. In this study, we used trehalose combined with Lactobacillus plantarum, Bifidobacterium longum, Bacillus subtilis, and Saccharomyces cerevisiae to explore whether dietary intervention can alleviate oxidative stress and inflammatory damage in early lactation and to evaluate the growth ability, acid production ability, antioxidant ability, non-specific adhesion ability, antibacterial ability, and other parameters to determine the optimal combinations and proportions. The results showed that the synbiotics composed of 2.5% trehalose and 1 × 107 cfu/g of Bifidobacterium longum could regulate the gut microbiota, and promote mammary gland development in dams by reducing progesterone (PROG) content in the blood, increasing prolactin (PRL) and insulin-like growth factor-1 (IGF-1) content, enhancing their antioxidant and immune abilities, and effectively increasing the weight and lactation of early lactating dams. In addition, it can also affect the growth of offspring and the development of the intestinal barrier. These results indicate that trehalose synbiotics have great potential in alleviating oxidative stress and inflammatory damage in early lactation.

Novel Indirect Antioxidant Activity Independent of Nrf2 Exerted by Lactic Acid Bacteria

In recent years, the health benefits of lactic acid bacteria have garnered attention, but their antioxidant activity remains relatively underexplored. We have been analyzing the antioxidant activities of various dietary phytochemicals by assessing their ability to mitigate oxidative stressor-induced toxicity in zebrafish larvae through pretreatment. In this study, the antioxidant activities of 24 strains of heat-killed lactic acid bacteria from various origins were examined using this zebrafish assay system. The results revealed that all 24 strains possessed antioxidant activity that reduces hydrogen peroxide toxicity. Further detailed analysis using the H61 strain, which exhibited the strongest activity, showed that no direct antioxidant activity was observed in the assay system, suggesting that the detected antioxidant activity was entirely indirect. Moreover, it was found that pretreatment of zebrafish larvae with the H61 strain for more than 6 h was required to exert its antioxidant activity. This duration was similar to that required by dietary antioxidants that activate the Keap1-Nrf2 pathway, suggesting potential involvement of this pathway. However, analysis using Nrf2-knockout zebrafish revealed that the antioxidant activity of strain H61 is independent of Nrf2, indicating that it represents a novel indirect antioxidant activity that does not involve the Keap1-Nrf2 pathway. To further characterize this activity, the ability to mitigate the toxicity of oxidative stressors other than hydrogen peroxide was examined. The results indicated that while the toxicity of tert-butyl hydroperoxide was reduced, unlike with the Keap1-Nrf2 pathway, it was not effective in counteracting the toxicity of paraquat or arsenite, which generate superoxide radicals. In conclusion, we have identified a novel indirect antioxidant activity in lactic acid bacteria.

Genetic Variations in the NRF2 Microsatellite Contribute to the Regulation of Bovine Sperm-Borne Antioxidant Capacity

Nuclear factor (erythroid-derived 2)-like 2 (NRF2) is a transcription factor protein-coding gene, considered a master regulator of the cellular stress response. The genetic variations of the NRF2 could influence its transcriptional profile and, subsequently, the stress resilience in all cell types, including sperm cells. Therefore, the sperm-borne antioxidants abundance in association with the genetic variation of a GCC microsatellite located at the 5' upstream region of the NRF2 gene was investigated in young (n = 8) and old (n = 8) Holstein bulls' sperm cells at different seasons. The sperm DNA was sequenced using Sanger sequencing, while- the sperm-borne mRNA analysis was carried out using the synthesized cDNA and qPCR. The data were statistically analyzed using GraphPad Prism 10.0.2 software. The results showed that two bulls had a heterozygous genotype of eight and nine GCC repeats, while biallelic of eight, nine, and fifteen repeats were identified in two, ten, and two bulls, respectively. The computational in silico analysis revealed that the NRF2 upstream sequence with 15, 9, and 8 GCC repeats bound with 725, 709, and 707 DNA-binding transcription factor proteins, respectively. Lower quality of sperm DNA was detected in the spring season compared to other seasons and in young bulls compared to old ones, particularly in the summer and autumn seasons. The mRNA expression analysis revealed that the PRDX1 gene was the abundant transcript among the studied sperm-borne antioxidants and was significantly determined in old bulls' spermatozoa. Moreover, two transcripts of the NRF2 gene and antioxidant (SOD1, CAT, GPX1, TXN1, NQO1) genes displayed differential expression patterns between the age groups across seasons in an antioxidant-dependent manner. The bulls with a heterozygous GCC sequence exhibited elevated sperm-borne mRNA levels of NRF2 and PRDX1 transcripts. Taken together, the findings suggest that the NRF2-GCC microsatellite may contribute to the transcription regulation of NRF2 transcripts and their subsequent downstream antioxidants in bovine sperm cells.

Balanced Duality: H2O2-Based Therapy in Cancer and Its Protective Effects on Non-Malignant Tissues

Conventional cancer therapy strategies, although centered around killing tumor cells, often lead to severe side effects on surrounding normal tissues, thus compromising the chronic quality of life in cancer survivors. Hydrogen peroxide (H2O2) is a secondary signaling molecule that has an array of functions in both tumor and normal cells, including the promotion of cell survival pathways and immune cell modulation in the tumor microenvironment. H2O2 is a reactive oxygen species (ROS) crucial in cellular homeostasis and signaling (at concentrations maintained under nM levels), with increased steady-state levels in tumors relative to their normal tissue counterparts. Increased steady-state levels of H2O2 in tumor cells, make them vulnerable to oxidative stress and ultimately, cell death. Recently, H2O2-producing therapies-namely, pharmacological ascorbate and superoxide dismutase mimetics-have emerged as compelling complementary treatment strategies in cancer. Both pharmacological ascorbate and superoxide dismutase mimetics can generate excess H2O2 to overwhelm the impaired H2O2 removal capacity of cancer cells. This review presents an overview of H2O2 metabolism in the physiological and malignant states, in addition to discussing the anti-tumor and normal tissue-sparing mechanism(s) of, and clinical evidence for, two H2O2-based therapies, pharmacological ascorbate and superoxide dismutase mimetics.

Nrf2 Signaling Pathway: Focus on Oxidative Stress in Spinal Cord Injury

Spinal cord injury (SCI) is a serious, disabling injury to the central nervous system that can lead to motor, sensory, and autonomic dysfunction below the injury plane. SCI can be divided into primary injury and secondary injury according to its pathophysiological process. Primary injury is irreversible in most cases, while secondary injury is a dynamic regulatory process. Secondary injury involves a series of pathological events, such as ischemia, oxidative stress, inflammatory events, apoptotic pathways, and motor dysfunction. Among them, oxidative stress is an important pathological event of secondary injury. Oxidative stress causes a series of destructive events such as lipid peroxidation, DNA damage, inflammation, and cell death, which further worsens the microenvironment of the injured site and leads to neurological dysfunction. The nuclear factor erythrocyte 2-associated factor 2 (Nrf2) is considered to be a key pathway of antioxidative stress and is closely related to the pathological process of SCI. Activation of this pathway can effectively inhibit the oxidative stress process and promote the recovery of nerve function after SCI. Therefore, the Nrf2 pathway may be a potential therapeutic target for SCI. This review deeply analyzed the generation of oxidative stress in SCI, the role and mechanism of Nrf2 as the main regulator of antioxidant stress in SCI, and the influence of cross-talk between Nrf2 and related pathways that may be involved in the pathological regulation of SCI on oxidative stress, and summarized the drugs and other treatment methods based on Nrf2 pathway regulation. The objective of this paper is to provide evidence for the role of Nrf2 activation in SCI and to highlight the important role of Nrf2 in alleviating SCI by elucidating the mechanism, so as to provide a theoretical basis for targeting Nrf2 pathway as a therapy for SCI.

The role of deacetylase SIRT1 in allergic diseases

The silent information regulator sirtuin 1 (SIRT1) protein is an NAD+-dependent class-III lysine deacetylase that serves as an important post-transcriptional modifier targeting lysine acetylation sites to mediate deacetylation modifications of histones and non-histone proteins. SIRT1 has been reported to be involved in several physiological or pathological processes such as aging, inflammation, immune responses, oxidative stress and allergic diseases. In this review, we summarized the regulatory roles of SIRT1 during allergic disorder progression. Furthermore, we highlight the therapeutic effects of targeting SIRT1 in allergic diseases.

Targeting Nrf2 by bioactive peptides alleviate inflammation: expanding the role of gut microbiota and metabolites

Inflammation is a complex process that usually refers to the general response of the body to the harmful stimuli of various pathogens, tissue damage, or exogenous pollutants. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates cellular defense against oxidative damage and toxicity by expressing genes related to oxidative stress response and drug detoxification. In addition to its antioxidant properties, Nrf2 is involved in many other important physiological processes, including inflammation and metabolism. Nrf2 can bind the promoters of antioxidant genes and upregulates their expressions, which alleviate oxidation-induced inflammation. Nrf2 has been shown to upregulate heme oxygenase-1 expression, which promotes NF-κB activation and is closely related with inflammation. Nrf2, as a key factor in antioxidant response, is closely related to the expressions of pro-inflammatory factors, NF-κB pathway and cell metabolism. Bioactive peptides come from a wide range of sources and have many biological functions. Increasing evidence indicates that bioactive peptides have potential anti-inflammatory activities. This article summarized the sources, absorption and utilization of bioactive peptides and their role in alleviating inflammation via Nrf2 pathway. Bioactive peptides can also regulate gut microbiota and alter metabolites, which regulates the Nrf2 pathway through novel pathway and supplement the anti-inflammatory mechanisms of bioactive peptides. This review provides a reference for further study on the anti-inflammatory effect of bioactive peptides and the development and utilization of functional foods.

Probiotic Characteristics and Anti-Inflammatory Effects of Limosilactobacillus fermentum 664 Isolated from Chinese Fermented Pickles

Limosilactobacillus fermentum (L. fermentum) is widely used in industrial food fermentations, and its probiotic and health-promoting roles attracted much attention in the past decades. In this work, the probiotic potential of L. fermentum 664 isolated from Chinese fermented pickles was assessed. In addition, the anti-inflammatory properties and mechanisms were investigated using lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Results indicated that L. fermentum 664 demonstrated excellent acid and bile salt tolerance, adhesion capability, antimicrobial activity, and safety profile. L. fermentum 664 downregulated the release of inflammatory mediators, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and cyclooxygenase-2 (COX-2) stimulated with LPS. Moreover, L fermentum 664 inhibited the nuclear translocation of the nuclear factor κB (NF-κB) and the activation of mitogen-activated protein kinases (MAPKs) induced by LPS. This action was associated with a reduction in reactive oxygen species (ROS) levels and an enhanced expression of heme oxygenase-1 (HO-1) protein. Additionally, whole genome sequencing indicated that L. fermentum 664 contained genes that encode proteins with antioxidant and anti-inflammatory functions, including Cytochrome bd ubiquinol oxidase subunit I (CydA), Cytochrome bd ubiquinol oxidase subunit II (CydB), and NAD(P)H dehydrogenase quinone 1 (NQO1). In conclusion, our study suggested that L. fermentum 664 has the potential to become a probiotic and might be a promising strategy for the prevention of inflammation.

NRF2-mediated regulation of lipid pathways in viral infection

The first line of defense against viral infection of the host cell is the cellular lipid membrane, which is also a crucial first site of contact for viruses. Lipids may sometimes be used as viral receptors by viruses. For effective infection, viruses significantly depend on lipid rafts during the majority of the viral life cycle. It has been discovered that different viruses employ different lipid raft modification methods for attachment, internalization, membrane fusion, genome replication, assembly, and release. To preserve cellular homeostasis, cells have potent antioxidant, detoxifying, and cytoprotective capabilities. Nuclear factor erythroid 2-related factor 2 (NRF2), widely expressed in many tissues and cell types, is one crucial component controlling electrophilic and oxidative stress (OS). NRF2 has recently been given novel tasks, including controlling inflammation and antiviral interferon (IFN) responses. The activation of NRF2 has two effects: it may both promote and prevent the development of viral diseases. NRF2 may also alter the host's metabolism and innate immunity during viral infection. However, its primary function in viral infections is to regulate reactive oxygen species (ROS). In several research, the impact of NRF2 on lipid metabolism has been examined. NRF2 is also involved in the control of lipids during viral infection. We evaluated NRF2's function in controlling viral and lipid infections in this research. We also looked at how lipids function in viral infections. Finally, we investigated the role of NRF2 in lipid modulation during viral infections.

Oxidative stress in hair follicle development and hair growth: Signalling pathways, intervening mechanisms and potential of natural antioxidants

Hair follicle development and hair growth are regulated by multiple factors and multiple signalling pathways. The hair follicle, as an important skin appendage, is the basis for hair growth, and it has the functions of safeguarding the body, perceiving the environment and regulating body temperature. Hair growth undergoes a regular hair cycle, including anagen, catagen and telogen. A small amount of physiological shedding of hair occurs under normal conditions, always in a dynamic equilibrium. Hair loss occurs when the skin or hair follicles are stimulated by oxidative stress, inflammation or hormonal disorders that disrupt the homeostasis of the hair follicles. Numerous researches have indicated that oxidative stress is an important factor causing hair loss. Here, we summarize the signalling pathways and intervention mechanisms by which oxidative stress affects hair follicle development and hair growth, discuss existing treatments for hair loss via the antioxidant pathway and provide our own insights. In addition, we collate antioxidant natural products promoting hair growth in recent years and discuss the limitations and perspectives of current hair loss prevention and treatment.

S-Allylmercapto-N-Acetylcysteine (ASSNAC) Attenuates Osteoporosis in Ovariectomized (OVX) Mice

Osteoporosis is a bone-debilitating disease, demonstrating a higher prevalence in post-menopausal women due to estrogen deprivation. One of the main mechanisms underlying menopause-related bone loss is oxidative stress. S-allylmercapto-N-acetylcysteine (ASSNAC) is a nuclear factor erythroid 2-related factor 2 (Nrf2) activator and cysteine supplier, previously shown to have anti-oxidation protective effects in cultured cells and animal models. Here, we studied the therapeutic potential of ASSNAC with and without Alendronate in ovariectomized (OVX) female mice. The experimental outcome included (i) femur and L3 lumbar vertebra morphometry via Micro-Computed Tomography (μCT); (ii) bone remodeling (formation vs. resorption); and (iii) oxidative stress markers in bone marrow (BM) cells. Four weeks after OVX, there was a significant bone loss that remained evident after 8 weeks, as demonstrated via µCT in the femur (cortical and trabecular bone compartments) and vertebra (trabecular bone). ASSNAC at a dose of 50 mg/Kg/day prevented bone loss after the four-week treatment but had no significant effect after 8 weeks, while ASSNAC at a dose of 20 mg/Kg/day significantly protected against bone loss after 8 weeks of treatment. Alendronate prevented ovariectomy-induced bone loss, and combining it with ASSNAC further augmented this effect. OVX mice demonstrated high serum levels of both C-terminal cross-linked telopeptides of type I collagen (CTX) (bone resorption) and procollagen I N-terminal propeptide (P1NP) (bone formation) after 2 weeks, and these returned to control levels after 8 weeks. Alendronate, ASSNAC and their combination decreased CTX and increased P1NP. Alendronate induced oxidative stress as reflected by decreased glutathione and increased malondialdehyde (MDA) levels, and combining it with ASSNAC partially attenuated these changes. These results portray the therapeutic potential of ASSNAC for the management of post-menopausal osteoporosis. Furthermore, ASSNAC ameliorates the Alendronate-associated oxidative stress, suggesting its potential to prevent Alendronate side effects as well as improve its bone-protective effect.

Triclosan and its alternatives, especially chlorhexidine, modulate macrophage immune response with distinct modes of action

Since European regulators restricted the use of bacteriocidic triclosan (TCS), alternatives for TCS are emerging. Recently, TCS has been shown to reprogram immune metabolism, trigger the NLRP3 inflammasome, and subsequently the release of IL-1β in human macrophages, but data on substitutes is scarce. Hence, we aimed to examine the effects of TCS compared to its alternatives at the molecular level in human macrophages. LPS-stimulated THP-1 macrophages were exposed to TCS or its substitutes, including benzalkonium chloride, benzethonium chloride, chloroxylenol, chlorhexidine (CHX) and cetylpyridinium chloride, with the inhibitory concentration (IC10-value) of cell viability to decipher their mode of action. TCS induced the release of the pro-inflammatory cytokine TNF and high level of IL-1β, suggesting the activation of the NLRP3-inflammasome, which was confirmed by non-apparent IL-1β under the NLRP3-inhibitor MCC950 treatment d. While IL-6 release was reduced in all treatments, the alternative CHX completely abolished the release of all investigated cytokines. To unravel the underlying molecular mechanisms, we used untargeted LC-MS/MS-based proteomics. TCS and CHX showed the strongest cellular response at the protein and signalling pathway level, whereby pathways related to metabolism, translation, cellular stress and migration were mainly affected but to different proposed modes of action. TCS inhibited mitochondrial electron transfer and affected phagocytosis. In contrast, in CHX-treated cells, the translation was arrested due to stress conditions, resulting in the formation of stress granules. Mitochondrial (e.g. ATP5F1D, ATP5PB, UQCRQ) and ribosomal (e.g. RPL10, RPL35, RPS23) proteins were revealed as putative key drivers. Furthermore, we have demonstrated the formation of podosomes by CHX, potentially involved in ECM degradation. Our results exhibit modulation of the immune response in macrophages by TCS and its substitutes and illuminated underlying molecular effects. These results illustrate critical processes involved in the modulation of macrophages' immune response by TCS and its alternatives, providing information essential for hazard assessment.

Serum heme oxygenase-1 level predicts clinical outcome after acute ischemic stroke

AIMS

The relationship between heme oxygenase-1 (HO-1) and human ischemic stroke outcome remains unclear, which was investigated in this study.

METHODS

Acute ischemic stroke patients admitted within 24 h were enrolled. Serum HO-1 levels at baseline were measured via ELISA. Poor 3-month functional outcome was defined as modified Rankin Scale (mRS) score 3-6. Multivariable-adjusted binary logistic regression and restricted cubic spline models were employed to examine association between serum HO-1 and functional outcome. HO-1's additive prognostic utility was assessed by net reclassification index (NRI) and integrated discrimination improvement (IDI).

RESULTS

Of 194 eligible patients, 79 (40.7%) developed poor functional outcomes at 3-month follow-up. The highest quartile of serum HO-1 was independently associated with a lower risk of poor functional outcome (adjusted OR 0.13, 95% CI 0.04-0.45; p = 0.001) compared with the lowest HO-1 category. The relationship between higher HO-1 levels and reduced risk of poor functional outcome was linear and dose responsive (p = 0.002 for linearity). Incorporating HO-1 into the analysis with conventional factors significantly improved reclassification for poor functional outcomes (NRI = 41.2%, p = 0.004; IDI = 5.0%, p = 0.004).

CONCLUSIONS

Elevated serum HO-1 levels at baseline were independently associated with improved 3-month functional outcomes post-ischemic stroke. Serum HO-1 measurement may enhance outcome prediction beyond conventional clinical factors.

Redox System and Oxidative Stress-Targeted Therapeutic Approaches in Bladder Cancer

Bladder cancer (BCa) is the most common genitourinary malignancy, with a high global incidence and recurrence rate that is paired with an increasing caregiver burden and higher financial cost, in addition to increasing morbidity and mortality worldwide. Histologically, BCa is categorized into non-muscle invasive, muscle invasive, and metastatic BCa, on the basis of which the therapeutic strategy is determined. Despite all innovations and recent advances in BCa research, conventional therapies such as chemotherapy, immunotherapy, radiotherapy, and surgery fall short in the complete management of this important malignancy. Besides this worrying trend, the molecular basis of BCa development also remains poorly understood. Burgeoning evidence from experimental and clinical studies suggests that oxidative stress resulting from an imbalance between reactive oxygen species (ROS) generation and the body's antioxidant production plays an integral role in BCa development and progression. Hence, ROS-induced oxidative stress-related pathways are currently under investigation as potential therapeutic targets of BCa. This review focuses on our current understanding regarding ROS-associated pathways in BCa pathogenesis and progression, as well as on antioxidants as potential adjuvants to conventional BCa therapy.

A microencapsulated blend of botanicals supports weaning piglets during a lipopolysaccharide challenge by modulating liver inflammation and intestinal integrity

This study examined the action of a blend of botanicals (BOT) against lipopolysaccharide (LPS)-induced inflammation on cultured hepatocytes and weaning piglets. In vitro studies examined HepG2 cells treated with BOT and challenged with Escherichiacoli LPS for 8 d. BOT treatment reduced IL-6 concentration in cell culture media across time (P < 0.05) and decreased pro-inflammatory cytokine expression on days 1 and 8 of experiment (TNFα, IL-1β; P < 0.05). BOT also increased the expression of antioxidant enzymes (GPX-2, SOD, CAT) on day 8 (P < 0.05), which was supported by lowered reactive oxygen species concentration after LPS challenge (P < 0.1). The in vivo study was conducted with 72 weaning pigs, allotted into 24 pens and divided into 3 groups: a negative control (CTR-, basal diet), a challenged control (CTR+) that received an intraperitoneal injection of E. coli O55:B5 LPS on days 14 and 16, and a challenged treated group which received a diet containing 1.5 g/kg of microencapsulated BOT (BOT+) for the whole duration of the study. Growth performance was determined weekly and, on days 21 (1 animal per pen) and 28 (remaining animals), pigs were sacrificed to collect liver and jejunal tissues. After the challenge, BOT+ pigs had increased BW on days 21 (P < 0.05) and 28 (P < 0.1) compared to CTR+. Similar improvements in average daily gain and FCR on days 14 to 21 (P < 0.05) and 21 to 28 (P < 0.1) were also seen in BOT+ group. In the liver, compared to CTR+ pigs, BOT+ pigs had downregulated expression of TLR-4, IL-6, IFN-γ on day 21 (P < 0.05), and TLR-4, TNF-α, IL-8 on day 28 (P < 0.05). BOT+ also increased GPX-2 expression on days 21 and 28 (P < 0.05), while also upregulating SOD-1 and SOD-2 on day 21 (P < 0.05) and CAT on day 28 (P < 0.05) compared to CTR+. In the jejunum, BOT+ reduced inflammation by affecting cytokine expression (P < 0.05) and increasing the expression of tight-junction proteins, ZO-1 on day 21 and CLD-1 on day 28 (P < 0.05). Furthermore, BOT+ pigs had lower crypt depth on days 21 (P < 0.1) and 28 (P < 0.05), and increased villi-to-crypt ratio on days 21 and 28 (P < 0.05). By day 28, BOT+ intestinal measurements were restored to values similar to the CTR-. Finally, BOT+ also reduced mast cell activation on day 21 (P < 0.05) compared to CTR+. Considering all the findings, BOT controlled inflammatory activation and oxidative stress in liver cells, enhanced intestinal integrity, and as a result improved the growth performance of weaning piglets challenged with LPS.

Q-switched Nd:YAG laser protects human keratinocytes from oxidative stress and inflammation via AhR-Nrf2 pathway

In recent years, some treatments for esthetic and pathologic skin conditions have increasingly been based on the use of non-ablative neodymium-doped yttrium aluminum garnet (Nd:YAG) laser due to its greater penetration ability than other types of lasers, few contraindications, minimal side effects, no damage for epidermidis and the rapid recovery of the treated patients. The skin is frequently exposed to many stressors such as radiation, toxic substances, metabolites, foods, mechanical insults, and allergen exposition that cause oxidative damage and have a decisive influence on the aging process. The imbalance between reactive oxygen species, reactive nitrogen species, and the malfunctioning of the antioxidant defense system promotes the establishment of an excessive inflammatory process, which can induce various diseases including cancer and neurodegenerative disorders. The present study investigated the cytoprotective function of Q-switched Nd:YAG laser against stress aging and cell injury in HaCaT cells. We evaluated the effect of the laser on antioxidant defenses, inflammation, metalloproteinases' expression, and the AhR-Nrf2 pathway. Q-switched Nd:YAG is able to upregulate the AhR pathway and the expression of IL-6 and TGF-β, which are involved in wound repair process, and to downregulate the expression of MMP-2 and 9, so preventing the collagen degradation. Q-switched Nd:YAG can stimulate the cellular antioxidant defenses by activating the AhR-Nrf2 system.

Oxygen metabolism abnormality and Alzheimer's disease: An update

Oxygen metabolism abnormality plays a crucial role in the pathogenesis of Alzheimer's disease (AD) via several mechanisms, including hypoxia, oxidative stress, and mitochondrial dysfunction. Hypoxia condition usually results from living in a high-altitude habitat, cardiovascular and cerebrovascular diseases, and chronic obstructive sleep apnea. Chronic hypoxia has been identified as a significant risk factor for AD, showing an aggravation of various pathological components of AD, such as amyloid β-protein (Aβ) metabolism, tau phosphorylation, mitochondrial dysfunction, and neuroinflammation. It is known that hypoxia and excessive hyperoxia can both result in oxidative stress and mitochondrial dysfunction. Oxidative stress and mitochondrial dysfunction can increase Aβ and tau phosphorylation, and Aβ and tau proteins can lead to redox imbalance, thus forming a vicious cycle and exacerbating AD pathology. Hyperbaric oxygen therapy (HBOT) is a non-invasive intervention known for its capacity to significantly enhance cerebral oxygenation levels, which can significantly attenuate Aβ aggregation, tau phosphorylation, and neuroinflammation. However, further investigation is imperative to determine the optimal oxygen pressure, duration of exposure, and frequency of HBOT sessions. In this review, we explore the prospects of oxygen metabolism in AD, with the aim of enhancing our understanding of the underlying molecular mechanisms in AD. Current research aimed at attenuating abnormalities in oxygen metabolism holds promise for providing novel therapeutic approaches for AD.

Nuclear factor E2-associated factor 2 and musculoaponeurotic fibrosarcoma K mediate regulation glutathione peroxidase of Cristaria plicata after microcystin-induced oxidative stress

Nuclear factor E2-associated factor 2 (Nrf2)/Antioxidant Response Element (ARE) signaling pathway is an endogenous antioxidant pathway that protects cells from oxidative damage. This pathway is triggered when aquatic organisms are exposed to environmental toxicants. In this study, CpMafK (musculoaponeurotic fibrosarcoma K of Cristaria plicata) mRNA expression in hepatopancreas and gills were up regulated after Cristaria plicata (C. plicata) was exposed to microcystin (MC), which showed that CpMafK protected C. plicata from MC. After MC treatment and CpNrf2 (Nrf2 of Cristaria plicata) knockdown, the mRNA expression of CpMafK was down regulated. After MC treatment and CpMafK knockdown, the mRNA expression of CpNrf2 was down regulated. Indicating that the expression of CpNrf2 was positively correlated with CpMafK. CpGPx (GPx of Cristaria plicata) mRNA was also down regulated with the down regulation of CpMafK and CpNrf2. CpGPx promoter contains a variety of transcription factor binding sites, including Nrf2, ARE elements, etc. Gel blocking experiments showed that CpNrf2/CpMafK heterodimers were bound to CpGPx promoters in vitro. Dual luciferase reporter assay showed that CpNrf2/CpMafK heterodimer negatively regulated CpGPx promoter in cells. In conclusion, Nrf2 and MafK mediate regulation of GPx play a crucial role in protecting bivalves from MC.

SARS-CoV-2 infection and dysregulation of nuclear factor erythroid-2-related factor 2 (Nrf2) pathway

Coronavirus disease 2019 (COVID-19) is a recent pandemic caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) leading to pulmonary and extra-pulmonary manifestations due to the development of oxidative stress (OS) and hyperinflammation. The underlying cause for OS and hyperinflammation in COVID-19 may be related to the inhibition of nuclear factor erythroid 2-related factor 2 (Nrf2), a master regulator of antioxidative responses and cellular homeostasis. The Nrf2 pathway inhibits the expression of pro-inflammatory cytokines and the development of cytokine storm and OS in COVID-19. Nrf2 activators can attenuate endothelial dysfunction (ED), renin-angiotensin system (RAS) dysregulation, immune thrombosis, and coagulopathy. Hence, this review aimed to reveal the potential role of the Nrf2 pathway and its activators in the management of COVID-19. As well, we tried to revise the mechanistic role of the Nrf2 pathway in COVID-19.

Antioxidant System and Endoplasmic Reticulum Stress in Cataracts

The primary underlying contributor for cataract, a leading cause of vision impairment and blindness worldwide, is oxidative stress. Oxidative stress triggers protein damage, cell apoptosis, and subsequent cataract formation. The nuclear factor-erythroid 2-related factor 2 (Nrf2) serves as a principal redox transcriptional factor in the lens, offering a line of defense against oxidative stress. In response to oxidative challenges, Nrf2 dissociates from its inhibitor, Kelch-like ECH-associated protein 1 (Keap1), moves to the nucleus, and binds to the antioxidant response element (ARE) to activate the Nrf2-dependent antioxidant system. In parallel, oxidative stress also induces endoplasmic reticulum stress (ERS). Reactive oxygen species (ROS), generated during oxidative stress, can directly damage proteins, causing them to misfold. Initially, the unfolded protein response (UPR) activates to mitigate excessive misfolded proteins. Yet, under persistent or severe stress, the failure to rectify protein misfolding leads to an accumulation of these aberrant proteins, pushing the UPR towards an apoptotic pathway, further contributing to cataractogenesis. Importantly, there is a dynamic interaction between the Nrf2 antioxidant system and the ERS/UPR mechanism in the lens. This interplay, where ERS/UPR can modulate Nrf2 expression and vice versa, holds potential therapeutic implications for cataract prevention and treatment. This review explores the intricate crosstalk between these systems, aiming to illuminate strategies for future advancements in cataract prevention and intervention. The Nrf2-dependent antioxidant system communicates and cross-talks with the ERS/UPR pathway. Both mechanisms are proposed to play pivotal roles in the onset of cataract formation.

Effects of epigallocatechin-3-gallate on oxidative stress, inflammation, and bone loss in a rat periodontitis model

Background/purpose

Epigallocatechin-3-gallate (EGCG) is playing an increasingly important role in the treatment of oral diseases. However, its mechanisms remain to be clarified. This study aimed to investigate the effect of EGCG on oxidative and inflammatory stress and bone loss in experimental periodontitis.

Materials and methods

Periodontitis was induced in rats, followed by gavage using different concentrations of EGCG for 5 weeks. The levels of interleukin-1β (IL-1β), interleukin-18 (IL-18), tumor necrosis factor-α (TNF-α), superoxide dismutase (SOD) and malondialdehyde (MDA) in rats were measured. The degree of alveolar bone loss and the number of inflammatory cells were detected. The integrated optical density of nuclear factor erythroid 2-related factor (Nrf2), heme oxygenase-1 (HO-1), NLR pyrin domain-containing 3 (NLRP3) and nuclear factor-kappaB p65 (NF-κB p65) was measured.

Results

EGCG (200 mg/kg) significantly reduced alveolar bone loss in the ligated maxillary molars and the number of inflammatory cells in the EGCG-200 group compared with the periodontitis, EGCG-100 and EGCG-400 groups. 200 mg/kg was the optimal dose of EGCG and was used in subsequent experiments. The expression levels of IL-1β, IL-18, TNF-α and MDA were significantly lower and the expression level of SOD was significantly higher in the EGCG-200 group compared with the periodontitis group. The expression of NLRP3 and NF-κB p65 was significantly decreased, while the expression of Nrf2 and HO-1 was significantly increased in the EGCG-200 group compared with the periodontitis group.

Conclusion

These results suggest that EGCG inhibits oxidative stress and inflammatory responses in the periodontitis model by modulating the Nrf2/HO-1/NLRP3/NF-κB p65 signaling pathway, thereby decreasing alveolar bone loss.

Antioxidant Activity of Sweet Whey Derived from Bovine, Ovine and Caprine Milk Obtained from Various Small-Scale Cheese Plants in Greece before and after In Vitro Simulated Gastrointestinal Digestion

Whey-derived peptides have been associated with different biological properties, but most peptides are usually further hydrolyzed during the digestive process. In the present study, the antioxidant capacity of 48 samples of sweet whey (SW) derived from cheeses obtained from small-scale cheese plants made with bovine, ovine, caprine or a mixture of ovine/caprine milk was assessed using both cell-free and cell-based assays. SW digestates (SW-Ds) and a fraction (<3 kDa; SW-D-P3) thereof were obtained after in vitro digestion and subsequent ultrafiltration. Antioxidant properties using four different assays were evaluated before and after digestion. Our data showed higher values (p < 0.05) for ORAC, ABTS, FRAP and P-FRAP after in vitro digestion (SW-Ds and SW-D-P3) when compared with the corresponding values before digestion. In the non-digested SW, ORAC values were higher (p < 0.05) for the bovine SW compared with all the other samples. In contrast, the ABTS assay indicated a higher antioxidant activity for the ovine SW both before digestion and for SW-D-P3 compared with the bovine SW. The fraction SW-D-P3 of the ovine SW, using HT29 cells and H2O2 as an oxidizing agent, increased (p < 0.05) the cellular antioxidant activity. Furthermore, the same fraction of the ovine/caprine mixed SW increased, through the NF-κB pathway, the expression of SOD1 and CAT, genes implicated in the oxidative response in macrophage-like THP-1 cells. These findings indicate that SW, and particularly bovine and ovine SW, could be a candidate source for physical antioxidants in human and animal nutrition.

An electrogenetic interface to program mammalian gene expression by direct current

Wearable electronic devices are playing a rapidly expanding role in the acquisition of individuals' health data for personalized medical interventions; however, wearables cannot yet directly program gene-based therapies because of the lack of a direct electrogenetic interface. Here we provide the missing link by developing an electrogenetic interface that we call direct current (DC)-actuated regulation technology (DART), which enables electrode-mediated, time- and voltage-dependent transgene expression in human cells using DC from batteries. DART utilizes a DC supply to generate non-toxic levels of reactive oxygen species that act via a biosensor to reversibly fine-tune synthetic promoters. In a proof-of-concept study in a type 1 diabetic male mouse model, a once-daily transdermal stimulation of subcutaneously implanted microencapsulated engineered human cells by energized acupuncture needles (4.5 V DC for 10 s) stimulated insulin release and restored normoglycemia. We believe this technology will enable wearable electronic devices to directly program metabolic interventions.

Insulin-like growth factor 1 in heat stress-induced neuroinflammation: novel perspective about the neuroprotective role of chromium

Heat stress (HS) can cause a series of stress responses, resulting in numerous negative effects on the body, such as the diminished food intake, carcass quality and reproductive capacity. In addition to the negative effects on the peripheral system, HS leads to central nervous system (CNS) disorders given its toll on neuroinflammation. This neuroinflammatory process is mainly mediated by microglia and astrocytes, which are involved in the activation of glial cells and the secretion of cytokines. While the regulation of inflammatory signaling has a close relationship with the expression of heat shock protein 70 (Hsp70), HS-induced neuroinflammation is closely related to the activation of the TLR4/NF-κB pathway. Moreover, oxidative stress and endoplasmic reticulum (ER) stress are key players in the development of neuroinflammation. Chromium (Cr) has been widely shown to have neuroprotective effects in both humans and animals, despite the lack of mechanistic evidence. Evidence has shown that Cr supplementation can increase the levels of insulin-like growth factor 1 (IGF-1), a major neurotrophic factor with anti-inflammatory and antioxidant effects. This review highlights recent advances in the attenuating effects and potential mechanisms of Cr-mediated IGF-1 actions on HS-induced neuroinflammation, providing presently existing evidence supporting the neuroprotective role of Cr.

SARS-CoV-2 Inhibits NRF2-Mediated Antioxidant Responses in Airway Epithelial Cells and in the Lung of a Murine Model of Infection

Several viruses have been shown to modulate the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), the master regulator of redox homeostasis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the COVID-19 pandemic, also seems to disrupt the balance between oxidants and antioxidants, which likely contributes to lung damage. Using in vitro and in vivo models of infection, we investigated how SARS-CoV-2 modulates the transcription factor NRF2 and its dependent genes, as well as the role of NRF2 during SARS-CoV-2 infection. We found that SARS-CoV-2 infection downregulates NRF2 protein levels and NRF2-dependent gene expression in human airway epithelial cells and in lungs of BALB/c mice. Reductions in cellular levels of NRF2 seem to be independent of proteasomal degradation and the interferon/promyelocytic leukemia (IFN/PML) pathway. Furthermore, lack of the Nrf2 gene in SARS-CoV-2-infected mice exacerbates clinical disease, increases lung inflammation, and is associated with a trend toward increased lung viral titers, indicating that NRF2 has a protective role during this viral infection. In summary, our results suggest that SARS-CoV-2 infection alters the cellular redox balance by downregulating NRF2 and its dependent genes, which exacerbates lung inflammation and disease, therefore, suggesting that the activation of NRF2 could be explored as therapeutic approach during SARS-CoV-2 infection. IMPORTANCE The antioxidant defense system plays a major function in protecting the organism against oxidative damage caused by free radicals. COVID-19 patients often present with biochemical characteristics of uncontrolled pro-oxidative responses in the respiratory tract. We show herein that SARS-CoV-2 variants, including Omicron, are potent inhibitors of cellular and lung nuclear factor erythroid 2-related factor 2 (NRF2), the master transcription factor that controls the expression of antioxidant and cytoprotective enzymes. Moreover, we show that mice lacking the Nrf2 gene show increased clinical signs of disease and lung pathology when infected with a mouse-adapted strain of SARS-CoV-2. Overall, this study provides a mechanistic explanation for the observed unbalanced pro-oxidative response in SARS-CoV-2 infections and suggests that therapeutic strategies for COVID-19 may consider the use of pharmacologic agents that are known to boost the expression levels of cellular NRF2.

Characterization of early psychosis patients carrying a genetic vulnerability to redox dysregulation: a computational analysis of mechanism-based gene expression profile in fibroblasts

In view of its heterogeneity, schizophrenia needs new diagnostic tools based on mechanistic biomarkers that would allow early detection. Complex interaction between genetic and environmental risk factors may lead to NMDAR hypofunction, inflammation and redox dysregulation, all converging on oxidative stress. Using computational analysis, the expression of 76 genes linked to these systems, known to be abnormally regulated in schizophrenia, was studied in skin-fibroblasts from early psychosis patients and age-matched controls (N = 30), under additional pro-oxidant challenge to mimic environmental stress. To evaluate the contribution of a genetic risk related to redox dysregulation, we investigated the GAG trinucleotide polymorphism in the key glutathione (GSH) synthesizing enzyme, glutamate-cysteine-ligase-catalytic-subunit (gclc) gene, known to be associated with the disease. Patients and controls showed different gene expression profiles that were modulated by GAG-gclc genotypes in combination with oxidative challenge. In GAG-gclc low-risk genotype patients, a global gene expression dysregulation was observed, especially in the antioxidant system, potentially induced by other risks. Both controls and patients with GAG-gclc high-risk genotype (gclcGAG-HR) showed similar gene expression profiles. However, under oxidative challenge, a boosting of other antioxidant defense, including the master regulator Nrf2 and TRX systems was observed only in gclcGAG-HR controls, suggesting a protective compensation against the genetic GSH dysregulation. Moreover, RAGE (redox/inflammation interaction) and AGMAT (arginine pathway) were increased in the gclcGAG-HR patients, suggesting some additional risk factors interacting with this genotype. Finally, the use of a machine-learning approach allowed discriminating patients and controls with an accuracy up to 100%, paving the way towards early detection of schizophrenia.

Activation of Nrf2 pathway as a protective mechanism against oxidative stress-induced diseases: Potential of astaxanthin

Astaxanthin, a red-orange liposoluble carotenoid, has been the centre of considerable attention in recent years for its numerous biological activities, notably its potent antioxidant activity. It is reported that astaxanthin elicits these biological activities via a number of cellular pathways. The Nrf2/Keap1 pathway is a major regulator of the antioxidant defence system of cells; it modulates the expression of a plethora of genes related to redox homeostasis as well as cellular detoxification. The pathway has received lots of attention as a prospective therapeutic target for diseases related to oxidative stress and aging. Several reports have shown that the pathway is inducible by many natural compounds. This present work reviews the Nrf2/Keap1 pathway, its regulation and involvement in diseases, provides a brief overview of naturally occurring compounds as activators of the pathway as well as discusses the effect of astaxanthin on the pathway.

Astragaloside IV attenuates podocyte apoptosis through ameliorating mitochondrial dysfunction by up-regulated Nrf2-ARE/TFAM signaling in diabetic kidney disease

Defective antioxidant system as well as mitochondrial dysfunction contributes to the pathogenesis and progression of diabetic kidney disease (DKD). Nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated signaling is the central defensive mechanism against oxidative stress and therefore pharmacological activation of Nrf2 is a promising therapeutic strategy. In this study, using molecular docking we found that Astragaloside IV (AS-IV), an active ingredient from traditional formula of Huangqi decoction (HQD), exerted a higher potential to promote Nrf2 escape from Keap1-Nrf2 interaction via competitively bind to amino acid sites in Keap1. When podocyte exposed to high glucose (HG) stimulation, mitochondrial morphological alterations and podocyte apoptosis were presented and accompanied by Nrf2 and mitochondrial transcription factor A (TFAM) downregulation. Mechanistically, HG promoted a decrease in mitochondria-specific electron transport chain (ETC) complexes, ATP synthesis and mtDNA content as well as increased ROS production. Conversely, all these mitochondrial defects were dramatically alleviated by AS-IV, but suppression of Nrf2 with inhibitor or siRNA and TFAM siRNA simultaneously alleviated the AS-IV efficacy. Moreover, experimental diabetic mice exhibited significant renal injury as well as mitochondrial disorder, corresponding with the decreased expression of Nrf2 and TFAM. On the contrary, AS-IV reversed the abnormality and the Nrf2 and TFAM expression were also restored. Taken together, the present findings demonstrate the improvement of AS-IV on mitochondrial function, thereby resistance to oxidative stress-induced diabetic kidney injury and podocyte apoptosis, and the process is closely associated with activation of Nrf2-ARE/TFAM signaling.

Dissecting the potential role of ferroptosis in liver diseases: an updated review

Ferroptosis is a novel form of cell death, manifested by iron-dependent, non-apoptotic manner resulting from the intracellular accumulation of large clusters of reactive oxygen species (ROS) and lipid peroxides due to abnormal iron metabolism. Since the liver is the main organ of human body for storing iron, it is essential to perform in-depth investigation on the role and mechanistic basis of ferroptosis in the context of divergent liver diseases. We previously summarized the emerging role of ferroptosis among various liver diseases, however, the past few years have been a surge in research establishing ferroptosis as the molecular basis or treatment option. This review article concentrated on the accumulating research progress of ferroptosis in a range of liver diseases such as acute liver injury/failure (ALI/ALF), immune-mediated hepatitis, alcoholic liver disease (ALD), nonalcoholic fatty liver disease and liver fibrosis. Ferroptosis may be a promising target for the prevention and treatment of various liver diseases, providing a strategy for exploring new therapeutic avenues for these entities.

Ginkgo biloba extracts protect human retinal Müller glial cells from t-BHP induced oxidative damage by activating the AMPK-Nrf2-NQO-1 axis

OBJECTIVES

Retinal Müller glial cell loss is almost involved in all retinal diseases, especially diabetic retinopathy (DR). Oxidative stress significantly contributes to the development of Müller glial cell loss. Ginkgo biloba extracts (GBE) have been reported to possess antioxidant property, beneficial in treating human retinal diseases. However, little is known about its role in Müller glial cells. This study investigated the protective effect of GBE (prepared from ginkgo biloba dropping pills) in human Müller glial cells against tert-butyl hydroperoxide (t-BHP)-induced oxidative stress and its underlying molecular mechanism.

METHODS

MIO-M1 cells were pretreated with or without GBE prior to the exposure to t-BHP-induced oxidative stress. Cell viability, cell death profile and lipid peroxidation were subsequently assessed. Protein expression of the key anti-oxidative signalling factors were investigated.

KEY FINDINGS

We showed that GBE can effectively protect human MIO-M1 cells from t-BHP-induced oxidative injury by improving cell viability, reducing intracellular ROS accumulation and suppressing lipid peroxidation, which effect is likely mediated through activating AMPK-Nrf2-NQO-1 antioxidant respondent axis.

CONCLUSIONS

Our study is the first to reveal the great potentials of GBE in protecting human retinal Müller glial cell loss against oxidative stress. GBE might be used to prevent human retinal diseases particularly DR.

Protocadherin 20 promotes ferroptosis by suppressing the expression of Sirtuin 1 and promoting the acetylation of nuclear factor erythroid 2-related factor 2 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is characterized by a poor prognosis. Our previous work suggested that Protocadherin 20 (PCDH20) promoted ferroptosis in HCC. Nevertheless, the underlying mechanism remains elusive. Recently, we found that both the mRNA and protein levels of PCDH20 were upregulated in erastin- or sorafenib-treated HCC cells. Meanwhile, data showed that Sirtuin 1 (SIRT1) was markedly downregulated in PCDH20-SNU-449 cells. Additionally, overexpression of PCDH20 or erastin-treated cells dramatically decreased cell viability and colony-forming capacity of HCC cells, whereas blocking PCDH20 reversed these effects. Moreover, PCDH20 overexpression or treatment with erastin significantly downregulated the expression of SIRT1, Solute carrier family 7 member 11 (SLC7A11), as well as the ferroptosis-related protein glutathione peroxidase 4 (GPX4) and glutathione (GSH), while elevated malondialdehyde (MDA), 2'- 7'-dichlorofluorescein (DCF) and intercellular iron levels. Conversely, knockdown of PCDH20 upregulated SIRT1 and SLC7A11. Immunoprecipitation assay demonstrated that PCDH20 or erastin increased the amount of acetylated nuclear factor erythroid 2-related factor-2 (NRF2). This reducing effect of NRF2 deacetylation by PCDH20 was counteracted by restoring the expression of SIRT1. In addition, PCDH20 lowered the levels of GPX4, GSH, and cell viability, as well as resulted in an elevation in intercellular iron level, MDA, and DCF. These effects were reversed by SIRT1 expression. Besides, PCDH20 could promote ferroptosis by inhibiting SIRT1 from deacetylating NRF2, which led to the downregulation of SLC7A11, GPX4, and GSH both in vivo and in vitro. Our results signals that PCDH20 promotes ferroptosis by suppressing the expression of SIRT1 and thus, promoting the acetylation of NRF2in HCC.

Protein persulfidation: Rewiring the hydrogen sulfide signaling in cell stress response

The past few decades have witnessed significant progress in the discovery of hydrogen sulfide (H₂S) as a ubiquitous gaseous signaling molecule in mammalian physiology, akin to nitric oxide and carbon monoxide. As the third gasotransmitter, H₂S is now known to exert a wide range of physiological and cytoprotective functions in the biological systems. However, endogenous H₂S concentrations are usually low, and its potential biologic mechanisms responsible have not yet been fully clarified. Recently, a growing body of evidence has demonstrated that protein persulfidation, a posttranslational modification of cysteine residues (RSH) to persulfides (RSSH) elicited by H₂S, is a fundamental mechanism of H₂S-mediated signaling pathways. Persulfidation, as a biological switch for protein function, plays an important role in the maintenance of cell homeostasis in response to various internal and external stress stimuli and is also implicated in numerous diseases, such as cardiovascular and neurodegenerative diseases and cancer. In this review, the biological significance of protein persulfidation by H₂S in cell stress response is reviewed providing a framework for understanding the multifaceted roles of H₂S. A mechanism-guided perspective can help open novel avenues for the exploitation of therapeutics based on H₂S-induced persulfidation in the context of diseases.

Antioxidant and Neuroprotective Xenicane Diterpenes from the Brown Alga Dictyota coriacea

Five new xenicane diterpenes, including three rare nitrogen-containing derivatives, dictyolactams A (1) and B (2) and 9-demethoxy-9-ethoxyjoalin (3), a rare diterpene with a cyclobutanone moiety, named 4-hydroxyisoacetylcoriacenone (4), and 19-O-acetyldictyodiol (5), were isolated from an East China Sea collection of the brown alga Dictyota coriacea, along with 15 known analogues (6-20). The structures of the new diterpenes were elucidated by spectroscopic analyses and theoretical ECD calculations. All compounds had cytoprotective effects against oxidative stress in neuron-like PC12 cells. The antioxidant mechanism of 18-acetoxy-6,7-epoxy-4-hydroxydictyo-19-al (6) was related to the activation of Nrf2/ARE signaling pathway; it also showed significant neuroprotective effects against cerebral ischemia-reperfusion injury (CIRI) in vivo. This study provided xenicane diterpene as a promising lead scaffold for the development of potent neuroprotective agents against CIRI.

Rutin Attenuates Oxidative Stress Via PHB2-Mediated Mitophagy in MPP+-Induced SH-SY5Y Cells

Oxidative stress plays a crucial role in the occurrence and development of Parkinson's disease (PD). Rutin, a natural botanical ingredient, has been shown to have antioxidant properties. Therefore, the aim of this study was to investigate the neuroprotective effects of rutin on PD and the underlying mechanisms. MPP⁺(1-methyl-4-phenylpyridinium ions)-treated SH-SY5Y cells were used as an in vitro model of PD. Human PHB2-shRNA lentiviral particles were transfected into SH-SY5Y cells to interfere with the expression of Prohibitin2 (PHB2). The oxidative damage of cells was analyzed by detecting intracellular reactive oxygen species (ROS), malondialdehyde (MDA), and mitochondrial membrane potential (MMP). Western blotting was used to detect the protein expression of antioxidant factors such as nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NADPH quinone oxidoreductase-1 (NQO-1), and mitophagy factors PHB2, translocase of outer mitochondrial membrane 20 (TOM20), and LC3II/LC3I (microtubule-associated protein II light chain 3 (LC3II) to microtubule-associated protein I light chain 3 (LC3I)). In addition, we also examined the expression of PHB2 and LC3II/LC3I by immunofluorescence staining. MPP⁺ treatment significantly increased the generation of ROS and MDA and the level of MMP depolarization and decreased the protein expression of Nrf2, HO-1, NQO1, TOM20, PHB2, and LC3II/LC3I. In MPP⁺-treated SH-SY5Y cells, rutin significantly decreased the generation of ROS and MDA and the level of MMP depolarization and increased the protein expression of Nrf2, HO-1, NQO-1, TOM20, PHB2, and LC3II/LC3I. However, the protective role of rutin was inhibited in PHB2-silenced cells. Rutin attenuates oxidative damage which may be associated with PHB2-mediated mitophagy in MPP⁺-induced SH-SY5Y cells. Rutin might be used as a potential drug for the prevention and treatment of PD.

Effects of dietary theabrownins on production performance, egg quality and ovarian function of laying hens with different ages

This experiment was conducted to investigate the effect of theabrownins (TB) on production performance, egg quality, and ovarian function of laying hens at different ages. A total of 240 Lohmann laying hens were assigned in a 2 × 2 factorial design, which encompassed 2 layers ages (47-wk-old and 67-wk-old) and 2 dietary levels of TB (0 and 100 mg/kg) for 12 wk. Results showed that older layers had lower laying rate, egg mass, and higher feed-to-egg ratio (F/E), egg weight and unqualified egg rate than the younger layers (P_(AGE) < 0.01) during all the experimental period. The effect of TB was found to increase egg laying rate and feed efficiency during 5 to 8 wk, 9 to 12 wk and the overall phases and decreased unqualified egg rate during 1 to 4 wk and the overall phases (P_(TB) ≤ 0.05). The eggshell quality (strength, thickness), albumen quality (albumen height and Haugh unit) of eggs from older layers were decreased during overall phases (P_(AGE) ≤ 0.05). TB increased eggshell strength during all phases and enhanced eggshell thickness at the end of wk 4 and 8 and increased albumen height and Haugh unit at the end of wk 8 and 12 of older layers (P_{(Interaction)} ≤ 0.05). In addition, TB also increased egg quality of older layers after 14 d storage. A decrease in the serum concentration of progesterone, melatonin, follicle stimulating hormone, estradiol was observed in the older compared to the younger ones (P_(AGE) < 0.05), while the increase in serum concentration of progesterone, melatonin, anti-Müllerian hormone (AMH) were more emphasized when older hens received TB supplemented diet (P_{(Interaction)} < 0.05). The older layer demonstrated lower the concentration of glutathione (GSH) (P_(AGE) < 0.05). And the activity of glutathione-s-transferase (GST) was significantly decreased in layers under 67-wk-old (P_(AGE) <0.05). The increase in concentration of GSH and the decrease in concentration of malondialdehyde (MDA) were more pronounced when TB were supplemented in 67-wk-old layers (P_{(Interaction)} ≤ 0.05). Layers at 67-wk-old had lower mRNA expression of Heme oxygenase 1 (HO-1) (P_(AGE) < 0.01) in ovary. Dietary TB supplementation upregulated mRNA gene expression of HO-1, Nuclear factor E2 related factor 2 (Nrf2), Quinone oxidoreductase 1 (NQO1) (P_(TB) < 0.01). Dietary TB upregulated mRNA expression of ovarian reproductive hormone receptor (estrogen receptor 1 [ESR1] and steroidogenic acute regulatory protein 1 [StAR1]]; P_(TB) < 0.01). The results suggest feeding TB (100 mg/kg) could improve the egg production rate, egg quality, and antioxidant capacity of the ovary. Moreover, the effect of TB was more pronounced in older layers (64-wk-old vs. 47-wk-old).

Antioxidant Phytochemicals as Potential Therapy for Diabetic Complications

The global prevalence of diabetes continues to increase partly due to rapid urbanization and an increase in the aging population. Consequently, this is associated with a parallel increase in the prevalence of diabetic vascular complications which significantly worsen the burden of diabetes. For these diabetic vascular complications, there is still an unmet need for safe and effective alternative/adjuvant therapeutic interventions. There is also an increasing urge for therapeutic options to come from natural products such as plants. Hyperglycemia-induced oxidative stress is central to the development of diabetes and diabetic complications. Furthermore, oxidative stress-induced inflammation and insulin resistance are central to endothelial damage and the progression of diabetic complications. Human and animal studies have shown that polyphenols could reduce oxidative stress, hyperglycemia, and prevent diabetic complications including diabetic retinopathy, diabetic nephropathy, and diabetic peripheral neuropathy. Part of the therapeutic effects of polyphenols is attributed to their modulatory effect on endogenous antioxidant systems. This review attempts to summarize the established effects of polyphenols on endogenous antioxidant systems from the literature. Moreover, potential therapeutic strategies for harnessing the potential benefits of polyphenols for diabetic vascular complications are also discussed.

Linalool attenuated ischemic injury in PC12 cells through inhibition of caspase-3 and caspase-9 during apoptosis

Numerous studies have indicated the pharmacological properties of linalool, a volatile terpene alcohol found in many flowers and spice plants, including anti-nociceptive, anti-inflammatory, and neuroprotective activities. The aim of this study was to explore the mechanisms of neuroprotection provided by (±) linalool and its enantiomer, (R)-(-) linalool against oxygen, and glucose deprivation/reoxygenation (OGD/R) in PC12 cells. PC12 cells were treated with (±) linalool and (R)-(-) linalool before exposure to OGD/R condition. Cell viability, reactive oxygen species (ROS) production, malondialdehyde (MDA) level, DNA damage, and the levels of proteins related to apoptosis were evaluated using MTT, comet assay, and western blot analysis, respectively. IC50 values for the PC12 cells incubated with (±) linalool and (R)-(-) linalool were 2700 and 2600 μM after 14 h, as well as 5440 and 3040 μM after 18 h, respectively. Survival of the ischemic cells pre-incubated with (±) linalool and (R)-(-) linalool (100 μM of both) increased compared to the cells subjected to the OGD/R alone (p < .001). ROS and MDA formation were also decreased following incubation with (±) linalool and (R)-(-) linalool compared to the OGD/R group (p < .01). In the same way, pre-treatment with (±) linalool and (R)-(-) linalool significantly reduced OGD/R-induced DNA injury compared to that seen in OGD/R group (p < .001). (±) Linalool and (R)-(-) linalool also restored Bax/Bcl-2 ratio and cleaved caspase-3 and caspase-9 (p < .001, p < .01) following ischemic injury. The neuroprotective effect of linalool against ischemic insult might be mediated by alleviation of oxidative stress and apoptosis.

Drug Value of Drynariae Rhizoma Root-Derived Extracellular Vesicles for Neurodegenerative Diseases Based on Proteomics and Bioinformatics

Extracellular vesicles (EVs) are nano-sized membrane vesicles released by various cell types. Mammalian EVs have been studied in-depth, but the role of plant EVs has rarely been explored. For the first time, EVs from Drynariae Rhizoma roots were isolated and identified using transmission electron microscopy and a flow nano analyzer. Proteomics and bioinformatics were applied to determine the protein composition and complete the functional analysis of the EVs. Seventy-seven proteins were identified from Drynariae Rhizoma root-derived EVs, with enzymes accounting for 47% of the proteins. All of the enzymes were involved in important biological processes in plants. Most of them, including NAD(P)H-quinone oxidoreductase, were enriched in the oxidative phosphorylation pathway in plants and humans, and Alzheimer's disease, Huntington's disease, and Parkinson's disease, which are associated with oxidative stress in humans. These findings suggested that EVs from Drynariae Rhizoma roots could alleviate such neurological diseases and that enzymes, especially NAD(P)H-quinone oxidoreductase, might play an important role in the process.

Effect of one-time high load exercise on skeletal muscle injury in rats of different genders: oxidative stress and mitochondrial responses

PURPOSE

To evaluate the impact of one-time high load exercise on skeletal muscle injury and analysis its mechanism in different genders.

METHODS

Twenty-four male and 24 female rats were divided randomly into four groups respectively: control, 0 h, 6 h, and 24 h after exercise. The activities of creatine kinase (CK), lactate dehydrogenase (LDH), and myohemoglobin (MYO) in serum, the expression level of oxidative stress markers, mitochondrial respiratory chain complex enzyme, and the apoptosis related protein in quadriceps were detected.

RESULTS

The results showed that the activities of CK, LDH and MYO in serum increased immediately after exercise and restored faster in female rats. More obvious structural disorder and apoptosis in male rats were showed. Malondialdehyde (MDA) and superoxide dismutase (SOD) were increased while catalase (CAT) and glutathione (GSH) were decreased in male rats. SOD, CAT and GSH were increased in female rats. Mitochondrial complex enzyme activity was decreased in males and increased in females.

CONCLUSIONS

The skeletal muscle injury in both genders of rat could be induced by one-time high load exercise due to the mitochondrial respiratory enzyme dysfunction and oxidative stress, which was relatively mild and recovered quicker in female rats.

Geniposidic Acid from Eucommia ulmoides Oliver Staminate Flower Tea Mitigates Cellular Oxidative Stress via Activating AKT/NRF2 Signaling

Eucommia ulmoides Oliver staminate flower (ESF) tea enjoys a good reputation in folk medicine and displays multiple bioactivities, such as antioxidant and antifatigue properties. However, the underlying biological mechanisms remain largely unknown. In this study, we aimed to investigate whether ESF tea can mitigate cellular oxidative stress. Crude ethyl alcohol extract and its three subfractions prepared by sequential extraction with chloroform, n-butyl alcohol and residual water were prepared from ESF tea. The results of antioxidant activity tests in vitro manifested n-butyl alcohol fraction (n-BUF) showed the strongest antioxidant capacity (DPPH: IC₅₀ = 24.45 ± 0.74 μg/mL, ABTS: IC₅₀ = 17.25 ± 0.04 μg/mL). Moreover, all subfractions of ESF tea, especially the n-BUF, exhibited an obvious capacity to scavenge the reactive oxygen species (ROS) and stimulate the NRF2 antioxidative response in human keratinocytes HaCaT treated by H₂O₂. Using ultra-high-performance liquid chromatography, we identified geniposidic acid (GPA) as the most abundant component in ESF tea extract. Furthermore, it was found that GPA relieved oxidative stress in H₂O₂-induced HaCaT cells by activating the Akt/Nrf2/OGG1 pathway. Our findings indicated that ESF tea may be a source of natural antioxidants to protect against skin cell oxidative damage and deserves further development and utilization.

Plant-Derived Polyphenols as Nrf2 Activators to Counteract Oxidative Stress and Intestinal Toxicity Induced by Deoxynivalenol in Swine: An Emerging Research Direction

The contamination of deoxynivalenol (DON) in feed is a global problem, which seriously threatens the productivity efficiency and welfare of farm animals and the food security of humans. Pig is the most sensitive species to DON, and is readily exposed to DON through its grain-enriched diet. The intestine serves as the first biological barrier to ingested mycotoxin, and is, therefore, the first target of DON. In the past decade, a growing amount of attention has been paid to plant-derived polyphenols as functional compounds against DON-induced oxidative stress and intestinal toxicity in pigs. In this review, we systematically updated the latest research progress in plant polyphenols detoxifying DON-induced intestinal toxicity in swine. We also discussed the potential underlying mechanism of action of polyphenols as Nrf2 activators in protecting against DON-induced enterotoxicity of swine. The output of this update points out an emerging research direction, as polyphenols have great potential to be developed as feed additives for swine to counteract DON-induced oxidative stress and intestinal toxicity.

Transcription factor NRF2 as potential therapeutic target for preventing muscle wasting in aging chronic kidney disease patients

Increased muscle protein catabolism leading to muscle wasting is a prominent feature of the syndrome of protein-energy wasting (PEW) in patients with chronic kidney disease (CKD). PEW and muscle wasting are induced by factors such as inflammation, oxidative stress and metabolic acidosis that activate the ubiquitin-proteasome system, the main regulatory mechanism of skeletal muscle degradation. Whether deficiency of nuclear factor erythroid 2-related factor 2 (NRF2), which regulates expression of antioxidant proteins protecting against oxidative damage triggered by inflammation, may exacerbate PEW has yet to be examined in aging patients with CKD. This review focuses on the hypothesis that NRF2 is involved in the maintenance of muscle mass and explores whether sustained activation of NRF2 by non-pharmacological interventions using nutraceutical activators to improve redox homeostasis could be a plausible strategy to prevent skeletal muscle disorders, including muscle wasting, sarcopenia and frailty associated with PEW in aging CKD patients.