The Nrf2-Keap1 defence pathway: role in protection against drug-induced toxicity

Alteration of reactive oxygen species master transcription factor Nrf2 in keratinocytes exposed to monoclonal pathogenic antibody AK23 against desmoglein-3 in pemphigus vulgaris

Keratinocytes in mucosal and skin tissues maintain tissue integrity via desmosomes and desmoglein-3 (Dsg3). Pemphigus Vulgaris (PV) is a life-threatening autoimmune blistering disease characterized by autoantibodies against Dsg3, disrupting desmosomes. Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates oxidative stress responses crucial for skin tissue protection. Although the pathogenesis of PV is known, the detailed molecular events remain unclear. This study investigates changes in Nrf2 expression in keratinocytes following pathogenic anti-Dsg3 antibody AK23 exposure, using dose- and time-dependent studies employing immunofluorescence analysis. N/TERT keratinocytes were cultured in keratinocytes serum-free medium and treated with AK23 at varying doses (5 µg/mL,40µg/mL,75µg/mL) and durations (2, 6, 24 h). Immunofluorescence staining was performed to assess the expression of Nrf2 and Dsg3. All fluorescent images were analyzed using ImageJ software. A dose-dependent increase in Dsg3 was noted following AK23 treatment, while Nrf2 expression and subcellular localization varied. Time-course analyses showed decreased Nrf2 at 24 h and increased Dsg3 levels. Early time-point (2 and 6 h) variations were evident in Nrf2 levels. This study highlights the impact of AK23 on Nrf2 expression, potentially disrupting Nrf2-mediated cytoprotection and implicating oxidative stress (ROS generation) in PV pathogenesis. Further investigation is necessary to validate the findings.

Carbamate compounds induced toxic effects by affecting Nrf2 signaling pathways

Carbamate (CBs) is a class of insecticides which is being known as an important cause of intentional or accidental poisoning. CBs, cause carbamylation of acetylcholinesterase at neuronal synapses and neuromuscular junction. Exposure to CBs through skin contact, inhalation, or ingestion can result in significant cholinergic toxicity. This is due to the elevation of acetylcholine levels at ganglionic synapses found in both the sympathetic and parasympathetic nervous systems, as well as muscarinic receptors located in target organs of the parasympathetic nervous system, nicotinic receptors situated in skeletal muscle tissue, and the central nervous system. The association between human illnesses and environmental exposures to CBs have been extensively studied in several studies. Although CBs-triggered toxicity leads to overproduction of reactive oxygen species (ROS), the detailed association between the toxicity under CBs exposure and NFE2-related factor 2 (Nrf2) signaling pathways has not been completely clarified. In this review we aimed to summarize the latest findings on the functional interrelationship between carbamates compounds and Nrf2 signaling.

Potential Role of Nrf2, HER2, and ALDH in Cancer Stem Cells: A Narrative Review

Cancer is one of the main causes of death among humans, second only to cardiovascular diseases. In recent years, numerous studies have been conducted on the pathophysiology of cancer, and it has been established that this disease is developed by a group of stem cells known as cancer stem cells (CSCs). Thus, cancer is considered a stem cell disease; however, there is no comprehensive consensus about the characteristics of these cells. Several different signaling pathways including Notch, Hedgehog, transforming growth factor-β (TGF-β), and WNT/β-catenin pathways cause the self-renewal of CSCs. CSCs change their metabolic pathways in order to access easy energy. Therefore, one of the key objectives of researchers in cancer treatment is to destroy CSCs. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays an essential role in the protection of CSCs from reactive oxygen species (ROS) and chemotherapeutic agents by regulating antioxidants and detoxification enzymes. Human epidermal growth factor receptor 2 (HER2) is a member of the tyrosine kinase receptor family, which contributes to the protection of cancer cells against treatment and implicated in the invasion, epithelial-mesenchymal transition (EMT), and tumorigenesis. Aldehyde dehydrogenases (ALDHs) are highly active in CSCs and protect the cells against damage caused by active aldehydes through the regulation of aldehyde metabolism. On the other hand, ALDHs promote the formation and maintenance of tumor cells and lead to drug resistance in tumors through the activation of various signaling pathways, such as the ALDH1A1/HIF-1α/VEGF axis and Wnt/β-catenin, as well as changing the intracellular pH value. Given the growing body of information in this field, in the present narrative review, we attempted to shed light on the function of Nrf2, HER2, and ALDH in CSCs.

The hepatotoxicity of γ-radiation synthesized 5-fluorouracil nanogel versus 5-fluorouracil in rats model

INTRODUCTION

The clinical use of 5-fluorouracil (5-FU), a routinely used chemotherapy medication, has a deleterious impact on the liver. Therefore, it is necessary to find a less harmful alternative to minimize liver damage. This study was designed to see how 5-fluorouracil nanogel influenced 5-FU-induced liver damage in rats.

METHODS

To induce liver damage, male albino rats were injected intraperitoneally with 5-FU (12.5 mg/kg) three doses/week for 1 month. The histopathological examination together with measuring the activities of serum alanine and aspartate aminotransferase enzymes (ALT and AST) were used to evaluate the severity of liver damage besides, hepatic oxidative stress and antioxidant markers were also measured. The hepatic gene expression of heme oxygenase-1 (HO-1), nuclear factor erythroid 2-related factor 2 (Nrf2) and its inhibitor Kelch-like ECH-associated protein-1(Keap-1) in addition to hepatic inflammatory mediators including tumor necrosis factor-α (TNF- α) and interleukins (IL-1β, IL-6) were detected.

RESULTS

5-Fu nanogel effectively attenuated 5-FU-induced liver injury by improving the hepatic structure and function (ALT and AST) besides the suppression of the hepatic inflammatory mediators (TNF- α, IL-1β and IL-6). Additionally, 5-FU nanogel alleviated the impaired redox status and restored the antioxidant system via maintaining the cellular homeostasis Keap-1/Nrf2/HO-1 pathway.

CONCLUSION

Consequently, 5-Fu nanogel exhibited lower liver toxicity compared to 5-FU, likely due to the alleviation of hepatic inflammation and the regulation of the cellular redox pathway.

Genistein Effects on Various Human Disorders Mediated via Nrf2 Signaling

Genistein is a flavonoid, mostly found in soybean extract and is widely used for its antioxidant and anti-inflammatory activities. Genistein can interact with estrogen receptors due to its structural similarities to estrogen. It also inhibits protein tyrosine kinases and affects a variety of intracellular signal transductions. Genistein attenuates oxidative stress via diverse cellular mechanisms. However, nuclear factor (erythroidderived 2)-like 2 (Nrf2), the main antioxidant regulator, potentiates genistein's antioxidant effects and reduces cell damage. Nrf2 includes of seven domains and controls the expression of the phase II antioxidant enzymes to decrease oxidative stress. In this review, we address findings related to Nrf2 signaling pathways in the context of genistein's effects on diverse human diseases.

Quercetin attenuates environmental Avermectin-induced ROS accumulation and alleviates gill damage in carp through activation of the Nrf2 pathway

Avermectin (AVM) is one of the most often used insecticides which is toxic to aquatic organisms, and cause oxidative-induced damages to the fish respiratory organ, the "gills". To better understand the mechanism by which an antioxidant reduces AVM-induced gill damage, we investigated the effects of Quercetin (Que) on AVM induction of oxidative stress to inhibit damages to the gills using common carp as a model organism. The Que is a fruit and vegetable rich flavonoid with antioxidant activity. In this study, four groups were created: the Control group, the Que group (400 mg/kg), the AVM group (2.404 μg/L), and the Que plus AVM group. The analytical methods were pathological structure examination, qPCR, Reactive Oxygen Species (ROS) and Western blot. The results showed that Que alleviated AVM-induced oxidative stress, inflammatory damage and apoptosis in the carp gills by activating the Nrf2 pathway. The mechanism was that Que alleviated the accumulation of ROS, reduced the balance between oxidation and antioxidant disrupted by AVM exposure, lowered the content of lipid peroxidation produced malondialdehyde (MDA), and increased the content of antioxidant enzymes including glutathione (GSH) and catalase (CAT). Nrf2 pathway was activated. Meanwhile, Que inhibited gill apoptosis in carp by decreasing the levels of Bax, Cytochrome C, Caspase9, Cleaved-Caspase3 and reduced Bcl2. This has important implications for future studies on Que and AVM. New suggestions are provided to reduce the threat of aquatic environmental pollution.

High Expression of NRF2 and Low Expression of KEAP1 Predict Worse Survival in Patients With Operable Triple-Negative Breast Cancer

PURPOSE

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer. Currently, no effective treatment options for this condition exist. Nuclear factor erythroid 2-related factor 2 (NRF2), encoded by nuclear factor erythroid-derived 2-like 2 (NFE2L2) gene and its endogenous inhibitor, Kelch-like ECH-associated protein 1 (KEAP1), both participate in cellular defense mechanisms against oxidative stress and contribute to chemoresistance and tumor progression in numerous types of cancers. This study aimed to evaluate the expression patterns of NRF2 and KEAP1 and their prognostic value in operable TNBC.

METHODS

Tissue microarrays were prepared using tumor tissues collected from 203 patients with TNBC who underwent surgery. Immunohistochemical staining analyses of NRF2 and KEAP1 were performed. The expression of each immunomarker was categorized into two groups (low or high) based on the median H-score. We analyzed the association between the expression of each immunomarker and clinicopathological information to predict survival. A total of 225 TNBC samples from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) dataset were used to validate our results.

RESULTS

NRF2 immunoreactivity was detected in the nucleus and was associated with histologic grade and Ki-67 index, whereas KEAP1 immunoreactivity was detected in the cytoplasm and was associated with the Ki-67 index. Survival analyses showed that NRF2 and KEAP1 expressions were independent prognostic factors for overall survival (OS) (hazard ratio [HR], 2.45 and 0.30; p = 0.015 and 0.016, respectively) and disease-free survival (HR, 2.27 and 0.42; p = 0.019 and 0.022, respectively). NFE2L2 mRNA expression was an independent prognostic factor for OS (HR, 0.59; p = 0.009) in the METABRIC dataset.

CONCLUSION

High NRF2 and low KEAP1 expressions independently predicted poor survival in patients with operable TNBC. Further investigations are warranted to examine the possible therapeutic benefits of targeting the KEAP1-NRF2 pathway for TNBC treatment.

Protocatechuic acid reduces H2O2-induced migration and oxidative stress of fibroblast-like synoviocytes in rheumatoid arthritis by activating Nrf2-Keap1 signaling pathway

Honeycomb (Nidus vespae) is traditional Chinese medicine and can treat rheumatoid arthritis (RA), and protocatechuic acid (PCA) is a bioactive component of honeycomb. This study aimed to investigate whether PCA could reduce the H₂O₂-induced migration and oxidative stress of RA fibroblast-like synoviocytes (RA-FLSs). H₂O₂-induced RA-FLSs were used to simulate the in vitro model of RA. The viability, apoptosis, migration, invasion, and oxidative stress of RA-FLSs were detected by Cell Counting Kit-8 (CCK-8), terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, wound healing, transwell assays, DCFDA staining, and malonaldehyde and superoxide dismutase enzyme-linked immunosorbent assay kits. The expression of migration and invasion-related proteins and Nrf2/Keap1 signaling pathway-related proteins was analyzed by western blotting. As a result, PCA suppressed the viability, migration, invasion, and oxidative and promoted apoptosis of H₂O₂-induced RA-FLSs by activating the Nrf2/Keap1 signaling pathway. ML-385, an Nrf2 inhibitor, could enhance the viability, migration, invasion, and oxidative and inhibited apoptosis of H₂O₂-induced RA-FLSs. In conclusion, PCA reduced H₂O₂-induced migration and oxidative stress of RA-FLSs by activating the Nrf2-Keap1 signaling pathway.

Dietary Supplementation of Sophora flavescens Root Extract Improved the Growth Performance, Antioxidant Capacity, Innate Immunity, and Disease Resistance against Edwardsiella tarda Challenge in Turbot (Scophthalmus maximus)

The impacts of dietary supplementation with graded levels of Sophora flavescens root extract (SFE) on growth performance, antioxidant capacity, immune status, and resistance against Edwardsiella tarda challenge in Scophthalus maximus were investigated in this study. In all, 600 turbot (initial body weight: 8.38 ± 0.07 g) were randomly distributed in 12 tanks with 50 fish per tank and fed four experimental diets supplemented with 0, 0.05%, 0.1%, or 0.2% SFE (named as: SFE0, SFE0.05, SFE0.1, and SFE0.2, respectively), for 56 days. The results showed that 0.1% and 0.2% SFE supplementation have significantly increased the FBW, WGR, SGR, and PER of turbot, while decreased the FCR of turbot (p < 0.05). Dietary SFE supplementations have significantly increased the activities of plasma SOD, CAT, GPx, T-AOC, GST and LZM, decreased plasma MDA contents in turbot under normal or challenge condition (p < 0.05). Meanwhile, SFE addition dramatically enhanced the hepatic mRNA expression of antioxidant parameters (including Nrf2, Keap1, SOD, CAT, Trx2, GST and GR) during the normal condition. mRNA levels of NF-κB p65, IκBα, TNF-α, TGF-β, and IL-10 in the liver of fish were notably up-regulated by SFE treatment during normal condition (p < 0.05), while the transcription of IL-1β was down-regulated by SFE whenever under normal or challenge condition. 0.1% and 0.2% SFE administration have significantly increased the survival rate of turbot against E. tarda challenge (p < 0.05). In conclusion, dietary SFE supplementation improved the growth performance, antioxidant activity and disease resistance of turbot, and SFE could be a potential feed additive for turbot.

Mothers modify the cost of reproduction by dynamic changes in antioxidant function and filial cannibalism

Investment in current reproduction may negatively influence subsequent fitness. Oxidative stress has been proposed as a potential mediator of this trade-off between current and future reproductive success. However, evidence of reproduction causing oxidative stress is limited, possibly owing to compensatory mechanisms that counteract oxidative insults. Here we test the idea that organisms protect against oxidative challenges through a dynamic interaction between behavioural and physiological adjustments at different stages of reproduction. To test this idea, we manipulated maternal care in the mouthbrooding cichlid fish Astatotilapia burtoni by allowing females to continue care (brooders) or by preventing care (non-brooders). We found that brooders depleted the pool of antioxidants as brood care progressed; however, we only observed increased oxidative DNA damage at the early stage of care relative to non-brooders, possibly owing to upregulated antioxidant protection during later stages of care. Most brooders adjusted parental investment by consuming some of their offspring during mouthbrooding. Intriguingly, the level of filial cannibalism was positively related to liver antioxidant function. These changes in antioxidant function and filial cannibalism allow parents to manage the cost of reproduction and are important for our understanding of how oxidative stress mediates life-history trade-offs.

Preventive effect of salmon sperm DNA on acute carbon tetrachloride-induced liver injury in mice through Nrf2/ARE and mitochondrial apoptosis pathway

Liver injury refers to the damage of liver function, which will seriously harm the body's health if it is not prevented and treated in time. Sporadic researches have reported that ingestion of DNA has a hepatoprotective effect, but its effect and mechanism were not clarified. The purpose of this study was to explore the preventive effect and mechanism of salmon sperm DNA on acute liver injury in mice induced by carbon tetrachloride (CCl₄). Six-week-old ICR (Institute of Cancer Research) male mice were used to establish a liver injury model by injecting with 4% CCl₄, silymarin, and three different concentrations of DNA solutions were given to mice by gavage for 14 days. The histological and pathological changes in the liver were observed. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum and the levels of oxidative and antioxidant markers such as malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione (GSH) in liver tissue were determined. The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA), and hepatic oxidative stress and apoptosis-related markers were determined by western blotting. The results showed that compared with the model group, the DNA test group significantly improved the liver pathological changes and the level of liver function, regulated liver oxidative stress, reduced hepatocyte apoptosis, and decreased the levels of inflammatory factors such as TNF-α and IL-6. Compared with the silymarin group, the high dose of DNA was even more effective in preventing liver injury. In conclusion, salmon sperm DNA has a potential protective effect against acute liver injury induced by CCl₄, which is achieved by regulating the Nrf2/ARE (nuclear factor erythroid 2 (NF-E2)-related factor 2/antioxidant responsive element) oxidative stress pathway and mitochondrial apoptosis pathway.

Pharmacotherapeutic potential of pomegranate in age-related neurological disorders

Age-related neurological disorders [AND] include neurodegenerative diseases [NDDs] such as Alzheimer's disease [AD] and Parkinson's disease [PD], which are the most prevalent types of dementia in the elderly. It also includes other illnesses such as migraine and epilepsy. ANDs are multifactorial, but aging is their major risk factor. The most frequent and vital pathological features of AND are oxidative stress, inflammation, and accumulation of misfolded proteins. As AND brain damage is a significant public health burden and its incidence is increasing, much has been done to overcome it. Pomegranate (Punica granatum L.) is one of the polyphenol-rich fruits that is widely mentioned in medical folklore. Pomegranate is commonly used to treat common disorders such as diarrhea, abdominal pain, wound healing, bleeding, dysentery, acidosis, microbial infections, infectious and noninfectious respiratory diseases, and neurological disorders. In the current review article, we aimed to summarize the data on the pharmacotherapeutic potentials of pomegranate in ANDs.

Galangin Nanoparticles Protect Acetaminophen-Induced Liver Injury: A Biochemical and Histopathological Approach

One of the main causes of acute liver failure is overdose with acetaminophen. Excessive consumption of acetaminophen leads to the production of NAPQI (N-acetyl-p-benzoquinone imine) through the activity of the enzyme cytochrome c oxidase. For this purpose, the effect of galangin nanoparticles with antioxidant activities will be evaluated for the treatment of acetaminophen-induced hepatotoxicity. In this study, after the synthesis of galangin nanoparticles and particle size determination, mice were divided into six groups. Before treatment, a single dose (350 mg/kg) of acetaminophen was administered by gavage in all groups. The activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), as well as biochemical factors FRAP and MDA in serum were measured and a histopathological study was performed. The prepared nanoparticles produced in this research were characterized by the SEM, DLS, and ZETA potential, and the average particle size was obtained in the range of 150 nm. Serum levels of liver enzymes (AST and ALT) in the nanoparticle group decreased significantly compared with the control group ( $P<0.05$ ). In the group without treatment, the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzymes increased significantly compared with the treatment groups. Also, galangin nanoparticles, at a dose of 20 mg/kg, improve cell damage in hepatocytes and preserve the tissue structure of the liver. Galangin nanoparticles reduce the acetaminophen-induced hepatotoxicity by reducing the number of liver function indices. According to our findings, the liver-protective effects of the nanoparticle may be due to its antioxidant properties.

Dietary α-lipoic acid alleviates deltamethrin-induced immunosuppression and oxidative stress in northern snakehead (Channa argus) via Nrf2/NF-κB signaling pathway

The goal of the study was to determine the ameliorative effects of dietary alpha-lipoic acid (α-LA) on deltamethrin (DEL)-induced immunosuppression and oxidative stress in northern snakehead (Channa argus). The northern snakeheads (15.38 ± 0.09 g) were exposed to DEL (0.242 μg/L) and fed with diets supplemented α-LA at 300, 600, and 900 mg/kg. After the 28-day exposure test, we obtained the following results: i) α-LA alleviates DEL-induced liver injury by reversing the increase of the serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and liver cytochrome P450 enzymes (Cytochrome P450 (cyp)1a and cyp1b) expression levels. ii) α-LA can reverse the DEL-induced reduction of serum complement 4 (C4), C3, immunoglobulin M (IgM), and lysozyme (LYS) levels and the increase of liver and intestine nuclear factor kappa B (nf-κb) p65, tumor necrosis factor (tnf)-α, interleukin (il)-1β, il-8, and il-6 gene expressions, while il-10 expression levels showed the opposite result. iii) α-LA reversed the reduction of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione-S-transferase (GST) and glutathione peroxidase (GSH-Px) levels in the liver and intestine induced by DEL, while malondialdehyde (MDA) showed the opposite result. iv) α-LA reversed the reduction of Cu/Zn sod, nuclear factor erythroid 2-related factor 2 (nrf2), NAD (P)H: quinone oxidoreductase (nqo)1, and heme oxygenase (ho)-1 antioxidant gene expression levels in the liver and intestine induced by DEL. Therefore, our study indicated that optimal α-LA (600 mg/kg) could attenuate DEL-induced toxicity (including liver damage, immunotoxicity, and oxidative stress) in northern snakehead via Nrf2/NF-κB signaling pathway. This is the first research that explores the alleviated effects of α-LA on DEL-induced toxicity damage in fish. This study provides a positive measure to reduce the toxicity damage caused by DEL to aquatic animals, and provides a theoretical basis for exploring the regulation mechanism of α-LA in toxic substances.

2-hydroxyethyl methacrylate-derived reactive oxygen species stimulate ATP release via TRPA1 in human dental pulp cells

Extracellular ATP (adenosine triphosphate) and transient receptor potential ankyrin 1 (TRPA1) channels are involved in calcium signaling in odontoblasts and dental pain. The resin monomer 2-hydroxyethyl methacrylate (HEMA), used in dental restorative procedures, is related to apoptotic cell death via oxidative stress. Although the TRPA1 channel is highly sensitive to reactive oxygen species (ROS), the effect of HEMA-induced ROS on ATP release to the extracellular space and the TRPA1 channel has not been clarified in human dental pulp. In this study, we investigated the extracellular ATP signaling and TRPA1 activation by HEMA-derived ROS in immortalized human dental pulp cells (hDPSC-K4DT). Among the ROS-sensitive TRP channels, TRPA1 expression was highest in undifferentiated hDPSC-K4DT cells, and its expression levels were further enhanced by osteogenic differentiation. In differentiated hDPSC-K4DT cells, 30 mM HEMA increased intracellular ROS production and ATP release, although 3 mM HEMA had no effect. Pretreatment with the free radical scavenger PBN (N-tert-butyl-α-phenylnitrone) or TRPA1 antagonist HC-030031 suppressed HEMA-induced responses. These results suggest that ROS production induced by a higher dose of HEMA activates the TRPA1 channel in human dental pulp cells, leading to ATP release. These findings may contribute to the understanding of the molecular and cellular pathogenesis of tertiary dentin formation and pain in response to dental biomaterials.

Mechanisms Involved in Neuroprotective Effects of Transcranial Magnetic Stimulation

Transcranial Magnetic Stimulation (TMS) is widely used in neurophysiology to study cortical excitability. Research over the last few decades has highlighted its added value as a potential therapeutic tool in the treatment of a broad range of psychiatric disorders. More recently, a number of studies have reported beneficial and therapeutic effects for TMS in neurodegenerative conditions and strokes. Yet, despite its recognised clinical applications and considerable research using animal models, the molecular and physiological mechanisms through which TMS exerts its beneficial and therapeutic effects remain unclear. They are thought to involve biochemical-molecular events affecting membrane potential and gene expression. In this aspect, the dopaminergic system plays a special role. This is the most directly and selectively modulated neurotransmitter system, producing an increase in the flux of dopamine (DA) in various areas of the brain after the application of repetitive TMS (rTMS). Other neurotransmitters, such as glutamate and gamma-aminobutyric acid (GABA) have shown a paradoxical response to rTMS. In this way, their levels increased in the hippocampus and striatum but decreased in the hypothalamus and remained unchanged in the mesencephalon. Similarly, there are sufficient evidence that TMS up-regulates the gene expression of BDNF (one of the main brain neurotrophins). Something similar occurs with the expression of genes such as c-Fos and zif268 that encode trophic and regenerative action neuropeptides. Consequently, the application of TMS can promote the release of molecules involved in neuronal genesis and maintenance. This capacity may mean that TMS becomes a useful therapeutic resource to antagonize processes that underlie the previously mentioned neurodegenerative conditions.

Silencing of Nrf2 in Litopenaeus vannamei, decreased the antioxidant capacity, and increased apoptosis and autophagy

Nuclear factor E2-related factor 2 (Nrf2) is a multifunctional transcription factor that plays an important role in antioxidant activities. However, its effect on antioxidant capacity in Litopenaeus vannamei, an economically important crustacean, remains unclear. In this study, the role of Nrf2 in response to oxidative stress in L. vannamei was determined by its effect on relevant gene expression and enzymatic activity. Nrf2 was cloned and analyzed. Results revealed that Nrf2 contains a 1575 bp open reading frame encoding 524 amino acids and a conserved bZIP Maf domain. The sequence similarity of Nrf2 between L. vannamei and Homarus americanus is 81%. Although the Nrf2 expression was detected in all tissues, the Nrf2 expression levels were the highest in the hepatopancreas, followed by the eyestalk and muscle. RNA interference significantly decreased the expression of antioxidant-related genes (SOD, GPX, CAT, Trx, and HO-1; p < 0.05), significantly upregulated the expression of autophagy genes (Atg3, Atg4, Atg5, Atg10, and Atg12; p < 0.05) and apoptosis genes (Caspase-3 and P53; p < 0.05). Moreover, SOD, CAT, and GPX enzyme activities decreased whereas the MDA activity increased. The histological results of the shrimp injected with dsRNA-Nrf2 showed that the hepatic tubules were irregularly arranged, the lumen was abnormal, and a few hepatic tubules were significantly enlarged compared with those of the dsRNA-EGFP group. The hepatocytes were also vacuolated. In conclusion, this study provided evidence that Nrf2 is involved in the regulation of antioxidant capacity, oxidative stress, apoptosis, and autophagy in shrimp.

Oxidative stress is involved in the activation of NF-κB signal pathway and immune inflammatory response in grass carp gill induced by cypermethrin and/or sulfamethoxazole

At present, the concentration of environmental pollutants, such as pesticides and antibiotics exposed in environment, especially in aquatic environment is increasing. Research on environmental pollutants has exploded in the last few years. However, studies on the combined effects of pesticides and antibiotics on fish are rare, especially the toxic damage to gill tissue is vague. In this paper, cypermethrin (CMN) and sulfamethoxazole (SMZ) were analyzed and found that there was a strong correlation between the pathways affected by the first 30 genes regulated by CMN and SMZ, respectively. Therefore, the toxic effects of CMN (0.651 μg L^-1) and/or SMZ (0.3 μg L^-1) on grass carp gill were studied in this paper. Histopathology, quantitative real-time PCR, and other methods were used to detect the tissue morphology, oxidative stress level, inflammation, and apoptosis-related indicators of the fish gills after exposure of 42 days. It was found that compared with the single exposure (CMN/SMZ) group, the combined exposure (MIX) group had a more pronounced oxidative stress index imbalance. At the same time, nuclear factor-κB (NF-κB) signal pathway was activated and immuno-inflammatory reaction appeared in MIX group. The expression of tumor necrosis factor (TNF-α) in the rising range is 2.94 times that of the C group, while the expression of interleukin 8 (IL-8) is as high as 32.67 times. This study reveals the harm of CMN and SMZ to fish, and provides a reference and basis for the rational use of pesticides and antibiotics.

Effects of Metal Oxide Nanoparticles in Zebrafish

Metal oxide nanoparticles (MO NPs) are increasingly employed in many fields with a wide range of applications from industries to drug delivery. Due to their semiconducting properties, metal oxide nanoparticles are commonly used in the manufacturing of several commercial products available in the market, including cosmetics, food additives, textile, paint, and antibacterial ointments. The use of metallic oxide nanoparticles for medical and cosmetic purposes leads to unavoidable human exposure, requiring a proper knowledge of their potentially harmful effects. This review offers a comprehensive overview of the possible toxicity of metallic oxide nanoparticles in zebrafish during both adulthood and growth stages, with an emphasis on the role of oxidative stress.

Nrf2/ARE axis signalling in hepatocyte cellular death

The Nrf2-ARE transcriptional pathway plays an important role amongst cellular defence systems regulating and ensuring adequacy of redox responses and oxidant signalling factors. Hepatocyte cellular death and injury is a prominent feature underlying liver pathologies. Diverse endogenous molecules and targets contribute to the outcome of cell survival and the consequent mode of cell death. Several research efforts focused on the confirmation of Nrf2 presence in cell death and its vital necessity against cell compromise, however, little they comprehend of such participation. Hepatocyte cell death modes discussed in this review including autophagy, apoptosis, necrosis, ferroptosis, pyroptosis, fibrosis and others, vary in response of the stimuli burdened. The current review presents a handful of highlights and crosstalk involved in the communication of Nrf2 signalling network with the "up to date" reported hepatocyte cell death modes and their underling mechanisms, and addressing key cellular networks of hepatocyte fate, through a perspective of Nrf2 as a critical transcriptional factor. Collectively, labelling the cross-transduction of Nrf2-ARE axis with key cell execution pathways could provide insights to therapeutic interventions and better research outcomes.

Nanogold Particles Suppresses 5-Flurouracil-Induced Renal Injury: An Insight into the Modulation of Nrf-2 and Its Downstream Targets, HO-1 and γ-GCS

The development of the field of nanotechnology has revolutionized various aspects in the fields of modern sciences. Nano-medicine is one of the primary fields for the application of nanotechnology techniques. The current study sheds light on the reno-protective impacts of gold nano-particles; nanogold (AuNPs) against 5-flurouracil (5-FU)-induced renal toxicity. Indeed, the use of 5-FU has been associated with kidney injury which greatly curbs its therapeutic application. In the current study, 5-FU injection was associated with a significant escalation in the indices of renal injury, i.e., creatinine and urea. Alongside this, histopathological and ultra-histopathological changes confirmed the onset of renal injury. Both gene and/or protein expression of nuclear factor erythroid 2-related factor 2 (Nrf-2) and downstream antioxidant enzymes revealed consistent paralleled anomalies. AuNPs administration induced a significant renal protection on functional, biochemical, and structural levels. Renal expression of the major sensor of the cellular oxidative status Nrf-2 escalated with a paralleled reduction in the renal expression of the other contributor to this axis, known as Kelch-like ECH-associated protein 1 (Keap-1). On the level of the effector downstream targets, heme oxygenase 1 (HO-1) and gamma-glutamylcysteine synthetase (γ-GCS) AuNPs significantly restored their gene and protein expression. Additionally, combination of AuNPs with 5-FU showed better cytotoxic effect on MCF-7 cells compared to monotreatments. Thus, it can be inferred that AuNPs conferred reno-protective impact against 5-FU with an evident modulatory impact on Nrf-2/Keap-1 and its downstream effectors, HO-1 and γ-GCS, suggesting its potential use in 5-FU regimens to improve its therapeutic outcomes and minimize its underlying nephrotoxicity.

Modulation of NRF2/ARE pathway- and cell death-related genes during drug-induced liver injury

Transcriptional factor NRF2 is an emerging tool in reviewing mechanistic behavior of drug-specific injury pathways. Drug-induced liver injury (DILI) represents a major clinical concern that often manifests oxidative stress and cell death. Despite the pivotal role of NRF2 pathway in liver pathologies, it is questioned whether NRF2 activation or regulatory efficiency could be hindered in by the severity of DILI and progression of cell death. In this study, we evaluate NRF2 as a biomarker to DILI in comparison to severity of injury as well as explore stress mediating factors affecting Nrf2 expression. In vivo DILI model was established in C57BL/6 mice by acetaminophen (APAP) at different toxic doses, confirmed by dose-dependent liver pathological changes and accompanied with in vitro time- and dose-dependent depletion of GSH and SOD in isolated primary mouse hepatocytes. Increase in liver NRF2 translocation and cytosolic content was observed in 70 mg/kg APAP-treated mice. At this subtoxic dose, liver Nrf2 transcription was increased in mice by 18.3-fold, a prominent downregulation was seen in ARE (antioxidant response element) genes; Hmox1, Nqo1 and Glcm, and apoptotic Bcl2 regulating genes. In addition, upregulation in necrosis inducer Parp2 was associated to downregulation in Hmgb1. Collectively, expression of genes related to cell survival were regulated at mild APAP hepatotoxicity. By increasing APAP dose, hemorrhagic necrosis and impaired genetic transcription in both Nrf2 and several other genes were evident. In conclusion, NRF2/ARE system and cell death modulation is halted by the increase of chemical stress and found directly associated with DILI severity.

Cyanidin-3-O-glucoside and its metabolite protocatechuic acid ameliorate 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induced cytotoxicity in HepG2 cells by regulating apoptotic and Nrf2/p62 pathways

The present study investigated the protective effects and mechanism of action of cyanidin-3-O-glucoside (C3G) and its major metabolite protocatechuic acid (PCA) against 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induced cytotoxicity in HepG2 cells. The results demonstrated that C3G and PCA dose-dependently suppressed PhIP-induced mutation in Salmonella typhimurium TA98, and inhibited PhIP-induced cytotoxicity and apoptosis in HepG2 cells. Western blot analysis indicated that C3G and PCA minimized PhIP-induced cell damage by reversing the abnormal expression of Bax/Bcl-2, Cytochrome c, cleaved Caspase-3, XIAP, Nrf2, HO-1, LC3 and p62 involved in intrinsic apoptotic and Nrf2/p62 pathways. Molecular docking results revealed that C3G and PCA were able to interfere with Nrf2 signaling and apoptotic cascade through binding to Keap1 and Bcl-2. Moreover, the protective effect of C3G was stronger than that of PCA. These findings suggested that dietary consumption of food sources rich in C3G can fight against the health risks of heterocyclic aromatic amines.

Lipoic acid. Kinetics and pluripotent biological properties and derivatives

Lipoic acid (LA) is globally known and its supplements are widely used. Despite its importance for the organism it is not considered a vitamin any more. The multiple metabolic forms and the differences in kinetics (absorption, distribution and excretion), as well as the actions of its enantiomers are analysed in the present article together with its biosynthetic path. The proteins involved in the transfer, biotransformation and activity of LA are mentioned. Furthermore, the safety and the toxicological profile of the compound are commented, together with its stability issues. Mechanisms of lipoic acid intervention in the human body are analysed considering the antioxidant and non-antioxidant characteristics of the compound. The chelating properties, the regenerative ability of other antioxidants, the co-enzyme activity and the signal transduction by the implication in various pathways will be discussed in order to be elucidated the pleiotropic effects of LA. Finally, lipoic acid integrating analogues are mentioned under the scope of the multiple pharmacological actions they acquire towards degenerative conditions.

Sub-lethal Camphor Exposure Triggers Oxidative Stress, Cardiotoxicity, and Cardiac Physiology Alterations in Zebrafish Embryos

Camphor is a terpene ketone with aromatic and volatile properties in nature derived from the bark of Cinnamomum camphora or synthesized from turpentine. Camphor exhibits various biological properties such as anti-microbial, anti-viral, anti-coccidial, and anti-cancer. It is also used as a form of topical medication for skin irritation, joint pain, and as a relief for itching from insect bites. However, even though the high dose of camphor has been documented to be toxic/lethal in humans in different studies, camphor's developmental toxicity has not yet been explored, and its extensive mechanism of action is still unclear. In the present study, we aimed to assess the toxic effects of camphor in zebrafish embryos in the initial developmental stages. The obtained results demonstrated that a sub-lethal dose of camphor caused a decrease in hatching rate, body length, and substantial elevation in malformation rate on zebrafish embryos. On further observation, in the following time frame, curved body and pericardial edema of zebrafish were also observed. Furthermore, exposure to a sub-lethal dose of camphor was also able to trigger cardiotoxicity in zebrafish larvae. Later, on subsequent biochemical analysis, it was found that the antioxidant capacity inhibition and oxidative stress elevation that occurred after camphor exposure might be associated with the inhibition of total superoxide dismutase (SOD) activity and an increase in reactive oxygen species (ROS) and malondialdehyde (MDA) concentration. In addition, compared to the control group, several apoptotic cells in treated zebrafish were also found to be elevated. Finally, after further investigation on marker gene expressions, we conclude that the developmental toxicity of camphor exposure might be associated with apoptosis elevation and oxidative stress. Taken together, the current study provides a better understanding of the developmental toxicity of camphor on zebrafish, a promising alternative animal model to assess the developmental toxicity of chemical compounds.

Chemical-Mediated Targeted Protein Degradation in Neurodegenerative Diseases

Neurodegenerative diseases, including Alzheimer’s disease, Huntington’s disease, and Parkinson’s disease, are a class of diseases that lead to dysfunction of cognition and mobility. Aggregates of misfolded proteins such as β-amyloid, tau, α-synuclein, and polyglutamates are known to be among the main causes of neurodegenerative diseases; however, they are considered to be some of the most challenging drug targets because they cannot be modulated by conventional small-molecule agents. Recently, the degradation of target proteins by small molecules has emerged as a new therapeutic modality and has garnered the interest of the researchers in the pharmaceutical industry. Bifunctional molecules that recruit target proteins to a cellular protein degradation machinery, such as the ubiquitin–proteasome system and autophagy–lysosome pathway, have been designed. The representative targeted protein degradation technologies include molecular glues, proteolysis-targeting chimeras, hydrophobic tagging, autophagy-targeting chimeras, and autophagosome-tethering compounds. Although these modalities have been shown to degrade many disease-related proteins, such technologies are expected to be potentially important for neurogenerative diseases caused by protein aggregation. Herein, we review the recent progress in chemical-mediated targeted protein degradation toward the discovery of drugs for neurogenerative diseases.

MicroRNAs in pemphigus and pemphigoid diseases

Autoimmune blistering diseases are a heterogenous group of dermatological disorders characterized by blisters and erosions of the skin and/or mucous membranes induced by autoantibodies against structural proteins of the desmosome or the dermal-epidermal adhesion complex including the hemidesmosome. They consist of the two major disease groups, pemphigus and pemphigoid diseases (PPDs). The diagnosis is based on clinical findings, histopathology, direct immunofluorescence, and detection of circulating autoantibodies. The pathogenesis is not fully elucidated, prognostic factors are lacking, and to date, there is no cure for PPDs. MicroRNAs (miRNAs) represent small, non-coding RNAs that play a pivotal role in the posttranscriptional regulation of gene expression. Their dysfunction was highlighted to play a significant role in the pathogenesis of various diseases. Even though a link between miRNAs and autoimmune blistering diseases had been suggested, the research of their involvement in the pathogenesis of PPDs is still in its infancy. miRNAs hold promise for uncovering new layers in the pathogenesis of PPDs, in order to improve diagnosis and also to develop potential therapeutic options. In the current article, we provide an overview regarding current knowledge of miRNAs in terms of complex pathogenesis of PPDs, and, also, their potential role as biomarkers, predictive factors and therapeutic targets.

Genipin induces developmental toxicity through oxidative stress and apoptosis in zebrafish

Genipin, an iridoid substance, is mainly derived from Gardenia jasminoides Ellis of the traditional Chinese medicine and is widely used in raw materials for the food additive gardenia blue and biological materials. The developmental toxicity of genipin has not been investigated, and its underlying mechanism is unclear. Therefore, in this study we attempt to investigate the potential developmental toxicity of genipin in zebrafish embryos/larvae. The results showed zebrafish embryos treated with 50 μg/ml dose of genipin display inhibited hatching rates and body length. The pericardial edema was observed. It was also found that genipin could induce cardio-toxicity, hepatotoxicity and nephrotoxicity in zebrafish larvae. After genipin treatment, the suppression of antioxidant capacity and increase of oxidative stress were showed for the triggered generation of ROS and MDA, and decreased activity of SOD. Compared with the 0.5% DMSO group, a number of apoptotic cells in zebrafish were increased after genipin exposure. By measuring marker gene expression with the using of qRT-PCR, we proposed that developmental toxicity after genipin treatment might be associated with oxidative stress and apoptosis increase. Our research offers a better understanding for developmental toxicity of genipin.

Neuroprotective effects of Myricetin on Epoxiconazole-induced toxicity in F98 cells

Epoxiconazole is one of the most commonly used fungicides in the world. The exposition of humans to pesticides is mainly attributed to its residue in food or occupational exposure in agricultural production. Because of its lipophilic character, Epoxiconazole can accumulate in the brain Heusinkveld et al. (2013) [1]. Consequently, it is urgent to explore efficient strategies to prevent or treat Epoxiconazole-related brain damages. The use of natural molecules commonly found in our diet represents a promising avenue. Flavonoids belong to a major sub-group compounds possessing powerful antioxidant activities based on their different structural and sterical properties [2]. We choose to evaluate Myricetin, a flavonoid with a wide spectrum of pharmacological effects, for its possible protective functions against Epoxiconazole-induced toxicities. The cytotoxicity induced by this fungicide was evaluated by the cell viability, cell cycle arrest, ROS generation, antioxidant enzyme activities, and Malondialdehyde production, as previously described in Hamdi et al., 2019 [3]. The apoptosis was assessed through the evaluation of the mitochondrial transmembrane potential (ΔΨm), caspases activation, DNA fragmentation, cytoskeleton disruption, nuclear condensation, appearance of sub-G0/G1 peak (fragmentation of the nucleus) and externalization of Phosphatidylserine. This study indicates that pre-treatment of F98 cells with Myricetin during 2 h before Epoxiconazole exposure significantly increased the survival of cells, restored DNA synthesis of the S phase, abrogated the ROS generation, regulated the activities of Catalase (CAT) and Superoxide Dismutase (SOD), and reduced the MDA level. The loss of mitochondrial membrane potential, DNA fragmentation, cytoskeleton disruption, chromatin condensation, Phosphatidylserine externalization, and Caspases activation were also reduced by Myricetin. Together, these findings indicate that Myricetin is a powerful natural product able to protect cells from Epoxiconazole-induced cytotoxicity and apoptosis.

New insights into the role of the Nrf2 signaling pathway in green tea catechin applications

Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a transcriptional signaling pathway that plays a crucial role in numerous clinical complications. Pivotal roles of Nrf2 have been proved in cancer, autoimmune diseases, neurodegeneration, cardiovascular diseases, diabetes mellitus, renal injuries, respiratory conditions, gastrointestinal disturbances, and general disorders related to oxidative stress, inflammation, apoptosis, gelatinolysis, autophagy, and fibrogenesis processes. Green tea catechins as a rich source of phenolic compounds can deal with various clinical problems and manifestations. In this review, we attempted to focus on intervention between green tea catechins and Nrf2. Green tea catechins especially epigallocatechin gallate (EGCG) elucidated the protective role of Nrf2 and its downstream molecules in various disorders through Keap-1, HO-1, NQO-1, GPx, GCLc, GCLm, NF-kB cross-link, kinases, and apoptotic proteins. Subsequently, we compiled an updated expansions of the Nrf2 role as a gate to manage and protect different disorders and feasible indications of green tea catechins through this signaling pathway. The present review highlighted recent evidence-based data in silico, in vitro, and in vivo studies on an outline for future clinical trials.

S-allylcysteine induces cytotoxic effects in two human lung cancer cell lines via induction of oxidative damage, downregulation of Nrf2 and NF-κB, and apoptosis

In this study, we investigated the putative cytotoxic effect elicited by the garlic-derived compound S-allylcysteine (SAC) in two human cancer cell lines (HCC827 and NCI-H1975) in order to develop an experimental approach to the therapeutic potential of this molecule for lung cancer. Cells were incubated for 24, 48 and 72 h in the presence of SAC (10 or 20 mM), which resulted in a concentration- and time-dependent decrease in cell viability and culture confluence in both cell lines. These effects were contrasted with - and validated through - those observed in an immortalized but nontumorigenic epithelial cell line from human bronchial epithelium (BEAS-2B, negative control) and an adenocarcinoma human alveolar basal epithelial cell line (A549, positive control). SAC (20 mM at 72 h) also increased the oxidative damage to lipids, augmented apoptosis, and decreased the expression of the nuclear factor erythroid 2-related factor 2 (Nrf2) and the nuclear factor kappa B (NF-κB) proteins in HCC827 and NCI-H1975 cells. Our results establish the efficacy of SAC in reducing malignant growth and proliferation of lung tumor cells. This effect is mediated by the induction of oxidative damage associated with the downregulation of Nrf2 and NF-κB and their corresponding signaling pathways.

Multilayered glycoproteomic analysis reveals the hepatotoxic mechanism in perfluorooctane sulfonate (PFOS) exposure mice

Perfluorooctane sulfonate (PFOS) is one of the most widely used and distributed perfluorinated compounds proven to cause adverse health outcomes. Datasets of ecotoxico-genomics and proteomics have given greater insights for PFOS toxicological effect. However, the molecular mechanisms of hepatotoxicity of PFOS on post-translational modifications (PTMs) regulation, which is most relevant for regulating the activity of proteins, are not well elucidated. Protein glycosylation is one of the most ubiquitous PTMs associated with diverse cellular functions, which are critical towards the understanding of the multiple biological processes and toxic mechanisms exposed to PFOS. Here, we exploit the multilayered glycoproteomics to quantify the global protein expression levels, glycosylation sites, and glycoproteins in PFOS exposure and wild-type mouse livers. The identified 2439 proteins, 1292 glycosites, and 799 glycoproteins were displayed complex heterogeneity in PFOS exposure mouse livers. Quantification results reveal that 241 dysregulated proteins (fold change ≥ 2, p < 0.05) in PFOS exposure mouse livers were involved in the lipid and xenobiotic metabolism. While, 16 overexpressed glycoproteins were exclusively related to neutrophil degranulation, cellular responses to stress, protein processing in endoplasmic reticulum (ER). Moreover, the interactome and functional network analysis identified HP and HSP90AA1 as the potential glycoprotein biomarkers. These results provide unique insights into a deep understanding of the mechanisms of PFOS induced hepatotoxicity and liver disease. Our platform of multilayered glycoproteomics can be adapted to diverse ecotoxicological research.

Table olives and health: a review

Table olives, a product of olive tree (Olea europaea L.), is an important fermented product of the Mediterranean Diet. Agronomical factors, particularly the cultivar, the ripening stage and the processing method employed are the main factors influencing the nutritional and non-nutritional composition of table olives and their organoleptic properties. The important nutritional value of this product is due to its richness in monounsaturated fat (MUFA), mainly oleic acid, fibre and vitamin E together with the presence of several phytochemicals. Among these, hydroxytyrosol (HT) is the major phenolic compound present in all types of table olives. There is a scarcity of in vitro, in vivo and human studies of table olives. This review focused comprehensively on the nutrients and bioactive compound content as well as the health benefits assigned to table olives. The possible health benefits associated with their consumption are thought to be primarily related to effects of MUFA on cardiovascular health, the antioxidant (AO) capacity of vitamin E and its role in protecting the body from oxidative damage and the anti-inflammatory and AO activities of HT. The influence of multiple factors on composition of the end product and the potential innovation in the production of table olives through the reduction of its final salt content was also discussed.

Protection against acute renal injury by naturally occurring medicines which act through Nrf2 signaling pathway

The cellular defense pathway plays a key role in maintaining the homeostasis, tissues and organisms. Nuclear factor E2-related factor 2 (Nrf2), as a key cell signaling pathway, plays an important role in encoding detoxification enzymes and other stress response mediators. Recent studies have shown that it is closely related to the prevention and treatment of acute kidney injury (AKI). Therefore, this article reviews the protective effects of Nrf2-related signaling pathways on acute kidney injury, and summarizes the strategies of natural pharmaceutical ingredients such as flavonoids, alkaloids, terpenes, phenylpropionic acid, polyphenols, and polysaccharides to prevent and treat acute kidney injury. It is of great significance to further study the relationship between Nrf2 regulated signal pathway and kidney disease and the development of new medicines for acute kidney injury treatment. It can also provide new ideas and treatment strategies for clinical treatment of acute kidney injury. PRACTICAL APPLICATIONS: This article reviewed the mechanisms by which the active ingredients of natural medicines slow down acute kidney injury through the Nrf2 pathway. It will help us to understand the regulatory role of the Nrf2 pathway in AKI more comprehensively, and provide a theoretical basis for further exploring the mechanism of more natural drugs to reduce acute kidney injury.

Prophylactic effect of aquatic extract of stevia on acetic acid induced-ulcerative colitis in male rats: a possible role of Nrf2 and PPARγ

Objectives Ulcerative colitis (UC) is a non-specific intestinal inflammatory disease. Several studies demonstrated that inflammation and oxidative stress play significant role in the pathogenesis of this disease. This study aimed to determine the protective effect and possible mechanism by which stevia affects the course of experimentally induced colitis. Methods Male rats were received stevia 20, 40, 80 mg/kg/day before induction of colitis by intra-rectal administration of 2 mL of 4% acetic acid, AA. Macroscopic and histopathological examination of the colon were done. Colonic content of catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), myeloperoxidase (MPO) and thiobarbituric acid reactive substances (TBARS) activities and serum levels of interleukin (IL)1- β and tumor necrosis factor (TNF)-α were assessed. Real time-PCR (RT-PCR) was done to determine the expression of NF-κB, Nrf2 and PPARγ genes. Spontaneous contraction and effects of increasing concentrations of acetylcholine and stevia have been studied on the isolated colonic segments. Results Stevia ameliorated colitis not only histopathologically but also it decreased the level of TNF-α, IL-1β, TBARS, MPO and the expression of NF-κB which were significantly increased in the AA group. The concentration of GSH, SOD, CAT and expression of Nrf2 and PPARγ were significantly increased with stevia. Moreover, stevia showed a relaxant effect on the colonic contractility which was increased in AA group. These all effects of stevia were more prominent with its highest dose. Conclusion Our results explored that, stevia acts protectively against UC by its anti-inflammatory and antioxidant properties which mediated by up-regulation of Nrf2 and PPARγ with downregulation of NF-κB. We suggest that stevia has the potential for treatment of chronic inflammatory diseases, such as UC.

Decreased Mitochondrial Function, Biogenesis, and Degradation in Peripheral Blood Mononuclear Cells from Amyotrophic Lateral Sclerosis Patients as a Potential Tool for Biomarker Research

Amyotrophic lateral sclerosis (ALS) is a multifactorial and progressive neurodegenerative disease of unknown etiology. Due to ALS’s unpredictable onset and progression rate, the search for biomarkers that allow the detection and tracking of its development and therapeutic efficacy would be of significant medical value. Considering that alterations of energy supply are one of ALS’s main hallmarks and that a correlation has been established between gene expression in human brain tissue and peripheral blood mononuclear cells (PBMCs), the present work investigates whether changes in mitochondrial function could be used to monitor ALS. To achieve this goal, PBMCs from ALS patients and control subjects were used; blood sampling is a quite non-invasive method and is cost-effective. Different parameters were evaluated, namely cytosolic calcium levels, mitochondrial membrane potential, oxidative stress, and metabolic compounds levels, as well as mitochondrial dynamics and degradation. Altogether, we observed lower mitochondrial calcium uptake/retention, mitochondria depolarization, and redox homeostasis deregulation, in addition to a decrease in critical metabolic genes, a diminishment in mitochondrial biogenesis, and an augmentation in mitochondrial fission and autophagy-related gene expression. All of these changes can contribute to the decreased ATP and pyruvate levels observed in ALS PBMCs. Our data indicate that PBMCs from ALS patients show a significant mitochondrial dysfunction, resembling several findings from ALS’ neural cells/models, which could be exploited as a powerful tool in ALS research. Our findings can also guide future studies on new pharmacological interventions for ALS since assessments of brain samples are challenging and represent a relevant limited strategy.

Effect of microcystin on the expression of Nrf2 and its downstream antioxidant genes from Cristaria plicata

Microcystin (MC) is a cyclic heptapeptide toxin. Nuclear factor erythocyte 2-related factor 2 (Nrf2) can enhance cellular survival by mediating phase 2 detoxification and antioxidant genes. In this study, CpNrf2 cDNA sequences were cloned from freshwater bivalve Cristaria plicata. The full-length CpNrf2 cDNA sequence was 4259 bp, and its homology was the highest with Mizuhopecten yessoensis, reaching 46%. CpNrf2 transcription levels were examined in all tested tissues, and the highest level was in hepatopancreas from C. plicata. The recombinant protein pET32-CpNrf2 was purified with the content of 1.375 mg/mL. The expression levels of CpNrf2 mRNA were raised in hepatopancreas after MC stimulation. After CpNrf2 knockdown, CpNrf2 mRNA levels were significantly down-regulated after 24 h. Compared with control group, the expression levels of ARE-driven enzymes (CpMnSOD, CpCuZnSOD, CpTRX, CpPrx, CpSe-GPx and Cpsigma-GST) were significantly increased, and those enzyme activities were also significantly up-regulated in MC-stimulated group. However, in CpNrf2-iRNA group, they were significantly down-regulated. The results revealed that Nrf2/ARE pathway is very crucial to protect molluscs from MC.

Discovering active sites in peptide Ala-Val-Thr-Phe that counter 2,2-azobis(2-methylpropanimidamidine)dihydrochloride-induced oxidative stress in HepG2 cells

The Ala-Val-Thr-Phe (AVTF) peptide derived from edible Dendrobium aphyllum was co-incubated with Lactobacillus amylolyticus in a previous study. The aim of the present study was to further examine the antioxidative and protective effects of the AVTF peptides through the analysis of free-radical quenching in HepG2 cells subjected to 2,2-azobis(2-methylpropanimidamidine)dihydrochloride (AAPH)-induced oxidative stress and to determine the active sites within the peptide. Variations in intracellular malondialdehyde levels indicated that these peptides protect HepG2 cells by preventing ROS attack and lipid peroxidation. Antioxidant enzymes and Nrf2 were downregulated in AVTF-treated but not in AAPH-treated HepG2 cells, whereas the electrically sensitive Keap1 was not susceptible to free radical-induced damage after AVTF treatment. However, this did not result in the activation of the Nrf2/Keap1 signaling pathway, thus indicating that one potential mechanism by which AVTF maintains homeostasis in HepG2 cells is by directly scavenging free radicals. Furthermore, quantum chemical calculations and the assessment of electronic-related properties associated with antioxidant activity revealed that the active sites of AVTF included N9-H11, which was further confirmed by the assessment of ROS levels in methylated AVTF-treated cells. The results of this study provide valuable insights into the active site N9-H11 in the Ala residue of AVTF, which influences the antioxidant activity of the peptide.

Activation of Nrf2/AREs-mediated antioxidant signalling, and suppression of profibrotic TGF-β1/Smad3 pathway: a promising therapeutic strategy for hepatic fibrosis - A review

Hepatic fibrosis (HF) is a wound-healing response that occurs during chronic liver injury and features by an excessive accumulation of extracellular matrix (ECM) components. Activation of hepatic stellate cell (HSC), the leading effector in HF, is responsible for overproduction of ECM. It has been documented that transforming growth factor-β1 (TGF-β1) stimulates superfluous accumulation of ECM and triggers HSCs activation mainly via canonical Smad-dependent pathway. Also, the pro-fibrogenic TGF-β1 is correlated with generation of reactive oxygen species (ROS) and inhibition of antioxidant mechanisms. Moreover, involvement of oxidative stress (OS) can be clearly elucidated as a fundamental event in liver fibrogenesis. Nuclear factor erythroid 2-related factor 2-antioxidant response elements (Nrf2-AREs) pathway, a group of OS-mediated transcription factors with diverse downstream targets, is associated with the induction of diverse detoxifying enzymes and the most pivotal endogenous antioxidative system. More specifically, Nrf2-AREs pathway has recently assigned as a new therapeutic target for cure of HF. The overall goal of this review will focus on recent findings about activation of Nrf2-AREs-mediated antioxidant and suppression of profibrotic TGF-β1/Smad3 pathway in the liver, providing an overview of recent advances in transcriptional repressors that dislocated during HF formation, and highlighting possible novel therapeutic targets for liver fibrosis.

Dietary selenium enhances the growth and anti-oxidant capacity of juvenile blunt snout bream (Megalobrama amblycephala)

Sodium selenite was added to basal diet at five levels (0.10, 0.42, 0.67, 1.06 and 1.46 mg Se/kg) and fed fish for 8 weeks. The dietary selenium requirement of juvenile blunt snout bream (Megalobrama amblycephala) was quantified. Dietaryseleniums at 0.67-1.06 mg Se/kg improved weight gain rate, specific growth rate and feed efficiency. The optimal amount was 0.96 mg/kg, for which the specific growth rate was 1.798%/day and the weight gain rate was 173.852% (p < 0.05). Se deposition in muscle was increased (p < 0.05) at ≥0.67 mg/kg, but moisture, protein, lipid and ash content were not affected. Physiological status and lipid metabolism were improved by 1.06-1.46 mg/kg dietary selenium based on total protein and albumin in plasma, and total cholesterol and triglycerides (p < 0.05). Activities of hepatic anti-oxidant enzymes catalase, total superoxide dismutase, glutathione peroxidase and reduced glutathione were enhanced at Se1.06 (p < 0.05). However, malondialdehyde content was lowered at Se1.06 (p < 0.05). Expression of anti-inflammatory cytokines, nuclear factor erythroid 2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 (Keap-1) in liver were elevated at Se1.06 (p < 0.05), as were mRNA levels of glutathione peroxidase, copper zinc superoxide dismutase and catalase. Expression of pro-inflammatory cytokines, interleukin 8, tumour necrosis factor-α and transforming growth factor-β were inhibited at 0.67-1.46 mg/kg (p < 0.05). In general, 0.96 mg/kg was optimal, and optimal selenium enhanced antioxidant stress tolerance and anti-inflammatory ability.

Insoluble-bound polyphenols of adlay seed ameliorate H2O2-induced oxidative stress in HepG2 cells via Nrf2 signalling

In this study, protective effects of insoluble-bound polyphenol extracts from adlay seed against H2O2-induced oxidative stress in HepG2 cells were investigated. Each fraction of insoluble-bound polyphenol extracts from adlay seed was obtained by separating with Sephadex LH-20 column and semi-preparative HPLC. Ferulic acid was found being the main active component of insoluble-bound polyphenol in adlay seed. The cytoprotective effects of ferulic acid against oxidative challenge were determined by cell viability, intracellular reactive oxygen stress change in HepG2 cells, western blot and apoptosis by flow cytometry. Ferulic acid had a positive correlation with cell viability and a negative correlation with apoptosis. Ferulic acid treatment increased the activity of GSH-PX, CAT, γ-GCS. Moreover, the nuclear factor E2 related factor (Nrf2) protein expression in the ferulic acid group positively correlated with the HO-1, GCLC and NQO1 protein levels. Thus the results demonstrated that ferulic acid, the main active component of insoluble-bound polyphenol in adlay seed could ameliorate H2O2-induced oxidative stress in HepG2 cells via Nrf2 signalling. The research can provide a reference for the in-depth study of its regulatory mechanism and the development of antioxidant related functional food and health products.

Nano-curcumin versus curcumin in amelioration of deltamethrin-induced hippocampal damage

We aimed to prove that oxidative stress is the main mechanism responsible for hippocampal neurotoxicity induced by deltamethrin (DLM). The protective role of curcumin (CMN) and nano-curcumin (NCMN) over this toxicity was studied. The rats were categorized into four groups: control, DLM, CMN and NCMN. The study continued for 30 days. Hippocampus was processed for histological, biochemical and immunohistochemical studies. Caspase-3, glial fibrillar acidic protein (GFAP), acetylcholinesterase (AChE), malondialdehyde (MDA), glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) were measured for DLM-induced oxidative stress (increased MDA by 354%/decreased GSH by 61%, SOD by 61%, CAT 57%). Oxidative stress induced apoptosis of hippocampal neurons through increasing Nrf2, gamma-glutamyl cysteine synthetase heavy subunit (GCS-HS) and light subunit (GCS-LS) and decreasing AChE. It increases the activity of astrocytes through increasing GFAP. Finally, oxidative stress has a bad impaction on cognitive function. Improvement of oxidative stress was observed with use of CMN and NCMN (decrease of MDA/increase of GSH, SOD, CAT). The level of Nrf2, GCS-HS and GCS-LS decreased, while AChE, GFAP increased. Improvement of cognitive function was observed in both groups. In conclusion, oxidative stress is the common mechanism responsible for DLM-induced hippocampal neurotoxicity. It exerts apoptosis of hippocampal neurons through increasing Nrf2, HS-GCS, LS-GCS and decreasing AChE. In addition, it activates astrocytes through increasing expression of GFAP. The protective role of CMN and CMMN is related to their potent antioxidant effect. Much improvement has been detected with NCMN as compared to CMN.

Liraglutide Up-regulation Thioredoxin Attenuated Müller Cells Apoptosis in High Glucose by Regulating Oxidative Stress and Endoplasmic Reticulum Stress

Purpose: Diabetic retinopathy (DR) has become one of the most important complications of diabetes which is the leading cause of vision impairment and blindness all over the world. Increasing evidence shows that reactive gliosis are basic pathological features of early DR. The study was aimed to explore the protective effect and mechanism of Liraglutide (LIRA) which has similar properties to Glucagon-like peptide-1 (GLP-1) on Müller cell damage induced by diabetes. Materials and methods: In vitro, the Müller cell was cultured in high glucose (HG) to establish the model of diabetic retinopathy. The apoptosis was detected using flow cytometry. Western blot and immunofluorescence were used to detect the expression of related proteins. DCFH-DA probe was used to detect the ROS generation. Results: The data showed that the apoptosis and the expression of GFAP were increased significantly with HG treatment. However, the apoptosis percentage and the expression of GFAP were decreased after LIRA treatment. Moreover, the expression of p-Erk/Nrf2/Trx-signaling pathway proteins was also up-regulated and the generation of ROS was decreased after LIRA treatment which was inhibited after treatment with U0126 (Erk inhibitor). Besides, endoplasmic reticulum stress (ER stress) related proteins were up-regulated after Trx down-regulation by transfection with sh-RNA. Conclusions: LIRA could protect Müller cells from HG-induced damage via activating p-Erk pathway through increasing Trx expression which attenuated oxidative stress and ER stress. Trx could play a key role in the process.

The Nrf2-Keap1 pathway: A secret weapon against pesticide persecution in Drosophila Kc cells

Nrf2-Keap1 pathway defends organisms against the detrimental effects of oxidative stress, and play pivotal roles in preventing xenobiotic-related toxicity. We designed experiments to explore and verify its role and function under deltamethrin (DM) stress. In experiments, DM was selected as the inducer, and Drosophila Kc cells were treated as the objects. The result showed the oxidative stress of cells proliferated in a very short time after DM treatment, reaching the maximum after one hour of treatment. The experimental data showed Nrf2 could be up-regulated and activated by DM which were manifested by the increase of Nrf2 mRNA, Nrf2 protein in the nucleus and the expression of detoxification enzyme genes. We further tested the activity of all groups, and found the survival rate of cells was basically proportional to the expression of Nrf2. Based on the above experimental results, Keap1 overexpression (K+), Nrf2 overexpression (N+) or interference (N-) cells were used to verified the relationship between Nrf2, cell survival and detoxification enzymes expression. We found the cell survival rate of N+ group was significantly higher than that of other groups and the expression of detoxification enzymes were increased compared to the control group. These results demonstrated that Nrf2 is related to cell detoxification and associated with the tolerance to DM. Our evidence suggested Nrf2 is a potential therapeutic target for oxidative stress and a potential molecular target gene of resistance control.

Toxic effects of glyphosate on intestinal morphology, antioxidant capacity and barrier function in weaned piglets

At present, the public is paying more attention to the adverse effects of pesticides on human and animal health and the environment. Glyphosate is a broad-spectrum pesticide that is widely used in agricultural production. In this manuscript, the effects of diets containing glyphosate on intestinal morphology, intestinal immune factors, intestinal antioxidant capacity and the mRNA expression associated with the Nrf2 signaling pathway were investigated in weaned piglets. Twenty-eight healthy female hybrid weaned piglets (Duroc × Landrace × Yorkshire) were randomly selected with an average weight of 12.24 ± 0.61 kg. Weaned piglets were randomly assigned into 4 treatment groups and fed a basal diet supplemented with 0, 10, 20, and 40 mg/kg glyphosate for a 35-day feeding trial. We found that glyphosate had no effect on intestinal morphology. In the duodenum, glyphosate increased the activities of CAT and SOD (linear, P < 0.05) and increased the levels of MDA (linear and quadratic, P < 0.05). In the duodenum, glyphosate remarkably increased the relative mRNA expression levels of Nrf2 (linear and quadratic, P < 0.05) and NQO1 (linear and quadratic, P < 0.05) and reduced the relative mRNA expression levels of GPx1, HO-1 and GCLM (linear and quadratic, P < 0.05). In the jejunum, glyphosate remarkably increased the relative mRNA expression levels of Nrf2 (linear and quadratic, P < 0.05) and decreased the relative mRNA expression levels of GCLM (linear and quadratic, P < 0.05). Glyphosate increased the mRNA expression levels of IL-6 in the duodenum (linear and quadratic, P < 0.05) and the mRNA expression levels of IL-6 in the jejunum (linear, P < 0.05). Glyphosate increased the mRNA expression of NF-κB in the jejunum (linear, P = 0.05). Additionally, the results demonstrated that glyphosate linearly decreased the ZO-1 mRNA expression levels in the jejunum and the mRNA expression of claudin-1 in the duodenum (P < 0.05). In the duodenum, glyphosate increased the protein expression levels of Nrf2 (linear, P = 0.025). Overall, glyphosate exposure may result in oxidative stress in the intestines of piglets, which can be alleviated by enhancing the activities of antioxidant enzymes and self-detoxification.