Targeting Nrf2 Signaling Pathway in Cancer Prevention and Treatment: The Role of Cannabis Compounds.

The development and progression of cancer are associated with the dysregulation of multiple pathways involved in cell proliferation and survival, as well as dysfunction in redox balance, immune response, and inflammation. The master antioxidant pathway, known as the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, regulates the cellular defense against oxidative stress and inflammation, making it a promising cancer prevention and treatment target. Cannabinoids have demonstrated anti-tumor and anti-inflammatory properties, affecting signaling pathways, including Nrf2. Increased oxidative stress following exposure to anti-cancer therapy prompts cancer cells to activate antioxidant mechanisms. This indicates the dual effect of Nrf2 in cancer cells-influencing proliferation and apoptotic processes and protecting against the toxicity of anti-cancer therapy. Therefore, understanding the complex role of cannabinoids in modulating Nrf2 might shed light on its potential implementation as an anti-cancer support. In this review, we aim to highlight the impact of cannabinoids on Nrf2-related factors, with a focus on cancer prevention and treatment. Additionally, we have presented the results of several research studies that combined cannabidiol (CBD) with other compounds targeting Nrf2. Further studies should be directed toward exploring the anti-inflammatory effects of cannabinoids in the context of cancer prevention and therapy.

Mulberrin alleviates triclocarban induced hepatic apoptosis and inflammation by regulating the ROS/NF-κB pathway in grass carp.

Triclocarban (TCC) is commonly used in household, personal care and industrial products and has been frequently detected in different aquatic ecosystems. Mulberrin (Mul) is a key component of the traditional Chinese medicine Romulus Mori with antioxidant and anti-inflammatory properties. The present study aimed to investigate the hepatotoxic effects of TCC in aquatic organisms and explore the protective roles of Mul. Herein, we found that exposure to TCC at environmentally realistic concentrations (5 µg/L) could impair liver function, along with impaired antioxidant defense and infiltration of inflammatory cells. Additionally, we found that TCC increased the ratio of TUNEL staining positive cells, accompanied by upregulation of pro-apoptotic protein (Bax, caspase3 and caspase9), and downregulation of anti-apoptotic proteins (Bcl2). In contrast, Mul supplementation reversed the hepatic pathological damage, ROS elevation, and apoptosis induced by TCC, likely due to hyperactivation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. Additionally, Mul supplementation suppressed the mRNA levels of proinflammatory factors (TNF-α, IL-1ß, IFN-γ, IL-6 and IL-8) and enhanced the mRNA levels of anti-inflammatory factors (TGFß1, TGFß2, IL4, IL10 and IL11) in the liver of carp. We also discovered that Mul supplementation suppressed TCC-induced nuclear nuclear factor κB (NF-κB) elevation. In conclusion, Mul enhances Nrf2 signaling cascades and counteracts the NF-κB inflammatory program to rescue hepatotoxicity induced by TCC, providing new insights into the hepatotoxic effects of TCC and potential protection strategies for heart injury induced by TCC.

[Leonurine inhibits ferroptosis in renal tubular epithelial cells by activating p62/Nrf2/HO-1 signaling pathway].

To investigate the protective effect and the potential mechanism of leonurine(Leo) against erastin-induced ferroptosis in human renal tubular epithelial cells(HK-2 cells), an in vitro erastin-induced ferroptosis model was constructed to detect the cell viability as well as the expressions of ferroptosis-related indexes and signaling pathway-related proteins. HK-2 cells were cultured in vitro, and the effects of Leo on the viability of HK-2 cells at 10, 20, 40, 60, 80 and 100 µmol·L~(-1) were examined by CCK-8 assay to determine the safe dose range of Leo administration. A ferroptosis cell model was induced by erastin, a common ferroptosis inducer, and the appropriate concentrations were screened. CCK-8 assay was used to detect the effects of Leo(20, 40, 80 µmol·L~(-1)) and positive drug ferrostatin-1(Fer-1, 1, 2 µmol·L~(-1)) on the viability of ferroptosis model cells, and the changes of cell morphology were observed by phase contrast microscopy. Then, the optimal concentration of Leo was obtained by Western blot for nuclear factor erythroid 2-related factor 2(Nrf2) activation, and transmission electron microscope was further used to detect the characteristic microscopic morphological changes during ferroptosis. Flow cytometry was performed to detect reactive oxygen species(ROS), and the level of glutathione(GSH) was measured using a GSH assay kit. The expressions of glutathione peroxidase 4(GPX4), p62, and heme oxygenase 1(HO-1) in each group were quantified by Western blot. RESULTS:: showed that Leo had no side effects on the viability of normal HK-2 cells in the concentration range of 10-100 µmol·L~(-1). The viability of HK-2 cells decreased as the concentration of erastin increased, and 5 µmol·L~(-1) erastin significantly induced ferroptosis in the cells. Compared with the model group, Leo dose-dependently increased cell via-bility and improved cell morphology, and 80 µmol·L~(-1) Leo promoted the translocation of Nrf2 from the cytoplasm to the nucleus. Further studies revealed that Leo remarkably alleviated the characteristic microstructural damage of ferroptosis cells caused by erastin, inhibited the release of intracellular ROS, elevated GSH and GPX4, promoted the nuclear translocation of Nrf2, and significantly upregulated the expression of p62 and HO-1 proteins. In conclusion, Leo exerted a protective effect on erastin-induced ferroptosis in HK-2 cells, which might be associated with its anti-oxidative stress by activating p62/Nrf2/HO-1 signaling pathway.

Nymphoides peltata Root Extracts Improve Atopic Dermatitis by Regulating Skin Inflammatory and Anti-Oxidative Enzymes in 2,4-Dinitrochlorobenzene (DNCB)-Induced SKH-1 Hairless Mice.

Nymphoides peltata is widely used pharmacologically in Traditional Chinese Medicine and Ayurvedic medicine as a diuretic, antipyretic, or choleretic and to treat ulcers, snakebites, and edema. Previous studies have shown that phytochemicals from N. peltata have physiological activities such as anti-inflammatory, anti-tumor, and anti-wrinkle properties. Nevertheless, research on the anti-atopic dermatitis (AD) effect of N. peltata extract is limited. This study was undertaken to assess the in vitro and in vivo anti-atopic and antioxidant activities of a 95% EtOH extract of N. peltata roots (NPR). PI-induced RBL-2H3 cells and two typical hapten mice (oxazolone-induced BALB/c mice and 2,4-dinitrochlorobenzene (DNCB)-induced SKH-1 hairless mice) were used to investigate the effect of NPR extract on AD. The expressions of AD-related inflammatory cytokines, skin-related genes, and antioxidant enzymes were analyzed by ELISA, immunoblotting, and immunofluorescence, and skin hydration was measured using Aquaflux AF103 and SKIN-O-MAT instruments. The chemical composition of NPR extract was analyzed using an HPLC-PDA system. In this study, NPR extracts were shown to most efficiently inhibit IL-4 in PI-induced RBL-2H3 cells and AD-like skin symptoms in oxazolone-BALB/c mice compared to its whole and aerial extracts. NPR extract markedly reduced DNCB-induced increases in mast cells, epidermal thickness, IL-4 and IgE expressions, and atopic-like symptoms in SKH-1 hairless mice. In addition, NPR extract suppressed DNCB-induced changes in the expressions of skin-related genes and skin hydration and activated the Nrf2/HO-1 pathway. Three phenolic acids (chlorogenic acid, 3,5-dicaffeoylquinic acid, and 3,4-dicaffeoylquinic acid) were identified by HPLC-PDA in NPR extract. The study shows that NPR extract exhibits anti-atopic activities by inhibiting inflammatory and oxidative stress and improving skin barrier functions, and indicates that NPR extract has potential therapeutic use for the prevention and treatment of AD.

Effect of a parenteral fish-oil-containing lipid emulsion on liver lipid perioxidation and antioxidative defenses in Lewis rats.

BACKGROUND: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), naturally abundant in fish oil (FO), are known for their anti-inflammatory and potential antioxidant properties. The aim in this article is to evaluate the effect of the infusion of a parenteral FO-containing lipid emulsion on markers of liver lipid peroxidation and oxidative stress in rats undergoing central venous catheterization (CVC). METHODS: After 5-day acclimatization, adult Lewis rats (n = 42) receiving a 20-g/day AIN-93M oral diet were randomly subdivided into four groups: (1) basal control (BC) (n = 6), without CVC or LE infusion; (2) SHAM (n = 12), with CVC but without LE infusion; (3) soybean oil (SO)/medium-chain triglyceride (MCT) (n = 12), with CVC and receiving LE without FO (4.3 g/kg fat); and (4) SO/MCT/FO (n = 12), with CVC and receiving LE containing 10% FO (4.3 g/kg fat). Animals from the BC group were euthanized immediately after acclimatization. The remaining groups of animals were euthanized after 48 or 72 h of surgical follow-up to assess profiles of liver and plasma fatty acids by gas chromatography, liver gene transcription factor Nrf2, F2-isoprostane lipid peroxidation biomarker, and the antioxidant enzymes glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) by enzyme-linked immunosorbent assay. R program (version 3.2.2) was utilized for data analysis. RESULTS: Compared with the other groups, liver EPA and DHA levels were higher in the SO/MCT/FO group, which also showed the highest liver Nrf2, GPx, SOD, and CAT levels and lower liver F2-isoprostane (P < 0.05). CONCLUSION: Experimental delivery of FO via EPA and DHA sources in a parenteral LE was associated with a liver antioxidant effect.

[Sagittaria sagittifolia polysaccharides regulates Nrf2/HO-1 to relieve liver injury caused by multiple heavy metals in vivo and in vitro].

This study explored whether Sagittaria sagittifolia polysaccharides(SSP) activates the nuclear factor erythroid-2-related factor2(Nrf2)/heme oxygenase-1(HO-1) signaling pathway to protect against liver damage jointly induced by multiple heavy metals. First, based on the proportion of dietary intake of six heavy metals in rice available in Beijing market, a heavy metal mixture was prepared for inducing mouse liver injury and HepG2 cell injury. Forty male Kunming mice were divided into five groups: control group, model group, glutathione positive control group, and low-and high-dose SSP groups, with eight mice in each group. After 30 days of intragastric administration, the liver injury in mice was observed by HE staining. In the in vitro experiment, MTT assay was conducted to detect the effects of SSP at 0.25, 0.5, 1, and 2 mg·mL~(-1) on HepG2 cell survival at different time points. The content of alanine transaminase(ALT) and aspartate aminotransferase(AST) in the 48-h cell culture fluid was measured using micro-plate cultivation method, followed by the detection of the change in reactive oxygen species(ROS) content by flow cytometry. The mRNA expression levels of Nrf2 and HO-1 in cells were determined by RT-PCR, and their protein expression by Western blot. HE staining results showed that compared with the model group, the SSP administration groups exhibited significantly alleviated inflammatory cell infiltration and fatty infiltration in the liver, with better outcomes observed in the high-dose SSP group. In the in vitro MTT assay, compared with the model group, SSP at four concentrations all significantly increased the cell survival rate, decreased the ALT, AST, and ROS content(P<0.05), and down-regulated Nrf2 and HO-1 mRNA and protein expression(P<0.05). SSP significantly improves inflammatory infiltration in the liver tissue of mice exposed to a variety of heavy metals and corrects the liver fat degeneration, which may be related to its regulation of the Nrf2/HO-1 signaling pathway, reduction of ROS, and alleviation of oxidative damage.

Protective Mechanism of Total Flavonoids of Lavender Against Skin Photoaging in Mice / 中国实验方剂学杂志

ObjectiveTo study the protective effect of total flavonoids of lavender on skin photoaging induced by ultraviolet B （UVB） in mice and to explore its mechanism from the perspective of nuclear factor E2-related factor 2 （Nrf2） antioxidant pathway. MethodEighty-four female KM mice were randomly divided into seven groups， namely blank group， model group， solvent group， vitamin E （0.013 g·kg-1） group， as well as low-， middle-， and high-dose （0.25， 1.25， 2.50 g·kg-1） groups of total flavonoids of lavender. The naked skin on the back of mice was irradiated with UVB for inducing optical damage. Thirty minutes before irradiation， the skin was coated with the total flavonoids of lavender. After continuous irradiation for one week， the skin moisture and elasticity on the back of mice were evaluated， and the effects of total flavonoids of lavender on histopathological changes in mouse skin were investigated by hematoxylin-eosin （HE） and Van Gieson （VG） staining. The levels of malondialdehyde （MDA）， superoxide dismutase （SOD）， total antioxidant capacity （T-AOC）， nitric oxide synthase （NOS）， and glutathione peroxidase （GSH-Px） after skin homogenization were detected by colorimetry， the inflammatory factors interleukin-1 （IL-1）， interleukin-6 （IL-6） and tumor necrosis factor-α （TNF-α） in skin tissue by enzyme-linked immunosorbent assay （ELISA）， and the mRNA expression levels of Nrf2， Kelch-like epichlorohydrin-associated protein 1 （Keap1）， BTB-CNC homology 1 （Bach1）， heme oxygenase-1 （HO-1）， quinone oxidoreductase 1 （NQO1）， and glutamate-cysteine ligase catalytic subunit （GCLC） by real-time polymerase chain reaction （Real-time PCR）. ResultCompared with the blank group， the model group exhibited significantly increased appearance score （P<0.01）， reduced skin moisture and elasticity （P<0.01）， pronounced pathological changes in the skin tissue like epidermal thickening， scabbing， small abscess， and severe injury， elevated MDA， NOS， IL-1， IL-6 and TNF-α （P<0.05， P<0.01）， lowered SOD， T-AOC， Nrf2， Keap1， NQO1 and GCLC mRNA expression （P<0.05，P<0.01）， and up-regulated Bach1 mRNA expression （P<0.01）. Compared with the model group， the total flavonoids of lavender at the low， middle， and high doses all remarkably reduced the appearance score （P<0.01）， enhanced the skin moisture and elasticity （P<0.01）， diminished the MDA， NOS， IL-1， IL-6， and TNF-α （P<0.05， P<0.01）， increased SOD， T-AOC， Nrf2， Keap1， NQO1， HO-1 and GCLC mRNA expression （P<0.05， P<0.01）， and down-regulated the expression of Bach1 mRNA （P<0.01）. ConclusionThe protective effect of the total flavonoids of lavender against skin photoaging in mice is significant， which may be related to its activation of Keap1/Nrf2/ARE signaling pathway， regulation of oxidative stress， and improvement of inflammatory response.

Cimicifugae Rhizoma Extract Attenuates Oxidative Stress and Airway Inflammation via the Upregulation of Nrf2/HO-1/NQO1 and Downregulation of NF-κB Phosphorylation in Ovalbumin-Induced Asthma.

Cimicifugae Rhizoma has been used as a medicinal herb for fever, pain, and inflammation in East Asia. We conducted this study because the effect of Cimicifugae Rhizoma extract (CRE) on allergic asthma has not yet been evaluated. To induce allergic airway inflammation, we intraperitoneally injected ovalbumin (OVA) mixed with aluminum hydroxide into mice twice at intervals of 2 weeks (Days 0 and 14) and then inhaled them thrice with 1% OVA solution using a nebulizer (Days 21 to 23). CRE (30 and 100 mg/kg) was administered orally daily for 6 days (Days 18 to 23). The mice showed remarkable reduction in allergic inflammation at 100 mg/kg of CRE, as evidenced by decreased inflammatory cell counts, pro-inflammatory cytokine levels, OVA-specific immunoglobulin E level, airway hyperresponsiveness, and production of mucus. Additionally, these effects were involved with the enhancement of heme oxygenase-1 (HO-1), NAD(P)H: quinone oxidoreductase (NQO1), and nuclear factor erythroid 2-related factor 2 (Nrf2) expression and reduction of nuclear factor-κB (NF-κB) phosphorylation and matrix metalloproteinase-9 expression. Our findings indicated that CRE effectively protected against OVA-induced inflammation and oxidative stress via upregulation of the Nrf2/HO-1/NQO1 signaling and downregulation of NF-κB phosphorylation in asthma caused by OVA.

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.

Biological and therapeutic activities of thymoquinone: Focus on the Nrf2 signaling pathway.

Thymoquinone is a monoterpenoid compound, which is derived from volatile and fixed oil of Nigella sativa (Ranunculaceae). This phytochemical compound has several biological effects, including antioxidant, antibacterial, antineoplastic, nephroprotective, hepatoprotective, gastroprotective, neuroprotective, anti-nociceptive, and anti-inflammatory activities. Thymoquinone shows pharmacological activities, including anti-hepatocellular carcinoma, nephroprotection, neuroprotection, retina protection, gastroprotection, cardioprotection, anti-allergy, reproductive system protection, bladder protection, and respiratory protection. It was found that these beneficial effects are mostly related to modulation of the Nrf2 signaling pathway by blockage of Keap1, stimulating the expression of the Nrf2 gene, and inducing the nuclear translocation of Nrf2. In the present review, the therapeutic effects of thymoquinone are overviewed through the Nrf2 signaling pathway.

Hepatoprotective Activity of Yellow Chinese Chive against Acetaminophen-Induced Acute Liver Injury via Nrf2 Signaling Pathway.

Glutathione, the most abundant intracellular antioxidant, protects cells against reactive oxygen species induced oxidative stress and regulates intracellular redox status. We previously demonstrated that yellow Chinese chive (ki-nira) increased the intracellular glutathione levels. Acetaminophen (APAP) is a commonly used analgesic. However, an overdose of APAP causes severe hepatotoxicity via depletion of the hepatic glutathione. In this study, we investigated the hepatoprotective effects of yellow Chinese chive extract (YCE) against APAP-induced hepatotoxicity in mice. YCE (25 or 100 mg/kg) was administered once daily for 7 d, and then APAP (700 mg/kg) was injected at 6 h before the mice were sacrificed. APAP treatment markedly increased the serum biological markers of liver injury such as alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase. Pretreatment with YCE significantly prevented the increases in the serum levels of these enzymes. Histopathological evaluation of the livers also revealed that YCE prevented APAP-induced centrilobular necrosis. Pretreatment with YCE dose-dependently elevated glutathione levels, but the difference was not significant. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a critical role in APAP-induced hepatotoxicity by regulating the antioxidant defense system. Therefore, we investigated the expression of Nrf2 and its target antioxidant enzyme. YCE led to an increased expression of Nrf2 and its target antioxidant enzymes, NAD(P)H quinone oxidoreductase 1 (NQO1), glutathione peroxidase (GPx), cystine uptake transporter (xCT), especially hemeoxygenase-1 (HO-1) in mice livers. These results suggest that YCE could induce HO-1 expression via activation of the Nrf2 antioxidant pathway, and protect against APAP-induced hepatotoxicity in mice.

Protective Effects of N-Acetylcysteine against Radiation-Induced Oral Mucositis In Vitro and In Vivo.

PURPOSE: Radiation-induced oral mucositis limits delivery of high-dose radiation to targeted cancers. Therefore, it is necessary to develop a treatment strategy to alleviate radiation-induced oral mucositis during radiation therapy. We previously reported that inhibiting reactive oxygen species (ROS) generation suppresses autophagy. Irradiation induces autophagy, suggesting that antioxidant treatment may be used to inhibit radiation-induced oral mucositis. MATERIALS AND METHODS: We determined whether treatment with N-acetyl cysteine (NAC) could attenuate radiation-induced buccal mucosa damage in vitro and in vivo. The protective effects of NAC against oral mucositis were confirmed by transmission electron microscopy and immunocytochemistry. mRNA and protein levels of DNA damage and autophagy-related genes were measured by quantitative real-time polymerase chain reaction and western blot analysis, respectively. RESULTS: Rats manifesting radiation-induced oral mucositis showed decreased oral intake, loss of body weight, and low survival rate. NAC intake slightly increased oral intake, body weight, and the survival rate without statistical significance. However, histopathologic characteristics were markedly restored in NAC-treated irradiated rats. LC3B staining of rat buccal mucosa revealed that NAC treatment significantly decreased the number of radiation-induced autophagic cells. Further, NAC inhibited radiation-induced ROS generation and autophagy signaling. In vitro, NAC treatment significantly reduced the expression of NRF2, LC3B, p62, and Beclin-1 in keratinocytes compared with that after radiation treatment. CONCLUSION: NAC treatment significantly inhibited radiation-induced autophagy in keratinocytes and rat buccal mucosa and may be a potentially safe and effective option for the prevention of radiation-induced buccal mucosa damage.

Therapeutic potential of glutathione-enhancers in stress-related psychopathologies.

The mammalian brain has high energy demands, which may become higher in response to environmental challenges such as psychogenic stress exposure. Therefore, efficient neutralization of reactive oxygen species that are produced as a by-product of ATP synthesis is crucial for preventing oxidative damage and ensuring normal energy supply and brain function. Glutathione (GSH) is arguably the most important endogenous antioxidant in the brain. In recent years, aberrant GSH levels have been implicated in different psychiatric disorders, including stress-related psychopathologies. In this review, we examine the available data supporting a role for GSH levels and antioxidant function in the brain in relation to anxiety and stress-related psychopathologies. Additionally, we identify several promising compounds that could raise GSH levels in the brain by either increasing the availability of its precursors or the expression of GSH-regulating enzymes through activation of Nuclear factor erythroid-2-related factor 2 (Nrf2). Given the high tolerability and safety profile of these compounds, they may represent attractive new opportunities to complement existing therapeutic manipulations against stress-related psychopathologies.

Luteolin prevents liver from tunicamycin-induced endoplasmic reticulum stress via nuclear factor erythroid 2-related factor 2-dependent sestrin 2 induction.

Endoplasmic reticulum (ER) stress designates a cellular response to the accumulation of misfolded proteins, which is related to disease progression in the liver. Luteolin (3',4',5,7-tetrahydroxyflavone) is a phytochemical found frequently in medicinal herbs. Although luteolin has been reported to possess the therapeutic potential to prevent diverse stage of liver diseases, its role in hepatic ER stress has not been established. Thus, the present study aimed to determine the role of luteolin in tunicamycin (Tm)-induced ER stress, and to identify the relevant mechanisms involved in its hepatoprotective effects. In hepatocyte-derived cells and primary hepatocytes, luteolin significantly decreased Tm- or thapsigargin-mediated C/EBP homologous protein (CHOP) expression. In addition, luteolin reduced the activation of three canonical signaling pathways related to the unfolded protein response, and decreased mRNA levels of glucose-regulated protein 78, ER DNA J domain-containing protein 4, and asparagine synthetase. Luteolin also significantly upregulated sestrin 2 (SESN2), and luteolin-mediated CHOP inhibition was blocked in SESN2 (+/-) cells. Moreover, luteolin resulted in phosphorylation of nuclear factor erythroid 2-related factor 2 (Nrf2), as well as increased nuclear Nrf2 expression. Deletion of the antioxidant response element in the human SESN2 promoter inhibited increased luciferase activation by luteolin, suggesting that Nrf2 is a critical transcription factor for luteolin-dependent SESN2 expression. In a Tm-mediated liver injury model, luteolin decreased serum alanine aminotransferase and aspartate aminotransferase activities, prevented degenerative changes and apoptosis of hepatocytes, and inhibited CHOP and glucose-regulated protein 78 expression in hepatic tissues. Therefore, luteolin may be an effective phytochemical to manage ER stress-related liver injury.

Leocarpinolide B attenuates LPS-induced inflammation on RAW264.7 macrophages by mediating NF-κB and Nrf2 pathways.

Macrophages-mediated inflammation is involved in the regulation of rheumatoid arthritis (RA). Sigesbeckiae Herba (SH) has been traditionally used for rheumatism. However, the bioactive ingredients of SH are still unclear. Recently, we isolated a compound (Leocarpinolide B, LB) from SH and identified its potent anti-inflammatory and antioxidant effects on RAW264.7 macrophages for the first time. LB effectively inhibited excessive production of nitric oxide (NO), prostaglandin E2 (PGE2), cytokines (IL-6, TNF-α and MCP-1), and the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthases (iNOS) in lipopolysaccharide (LPS)-induced RAW264.7 cells. LB blocked the degradation of inhibitor of kappa B (IκBα) and translocation of nuclear factor kappa B (NF-κB) p65. Additionally, LB reduced the intracellular reactive oxygen species, and increased the expression of heme oxygenase-1 (HO-1) and the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the presence or absence of LPS. The results suggested that LB might be one of the bioactive components of SH, and be potential for the treatment of RA and valuable to be further investigated.

Role of Nuclear Factor Erythroid 2-Related Factor 2 (NRF-2) Mediated Antioxidant Response on the Synergistic Antitumor Effect of L-Arginine and 5-Fluro Uracil (5FU) in Breast Adenocarcinoma.

Breast adenocarcinoma (BAC) in glandular tissue cells have excessive metastasis and invasion capability. The major challenges for the chemotherapy used for the management of BAC include chemoresistance and auto-immunosuppression in BAC. The 5-fluro uracil (5-FU) based therapy promotes the immune activation in BAC by targeting the regulatory T cells and myeloid-derived suppressor cells (MDSC). The beneficial effect of the combination of L-Arginine with 5-FU strives to be established in different pre-clinical and clinical conditions and explored in the scientific literature. L-Arginine induces NO production and potentiates the anticancer effect of 5-FU. NO-mediated signaling is regulated by nuclear factor erythroid 2-related factor 2 (NRF-2) mediated antioxidant response. NRF-2 mediated antioxidant mechanism always suppresses the formation of superoxide (O2-) as well as other reactive oxygen species (ROS). Thus the utilization of NO by O2- will be minimum in this combination therapy. The regulatory role of NRF-2 in regulation to Antioxidant Response Element (ARE) mediated cytoprotective gene expression in BAC remains unexplored. The present review summarizes the role of NRF-2 mediated antioxidant response on the synergistic antitumor effect of L-Arginine and 5-FU in BAC. This review brought new insight into the management of BAC and in the same context, a hypothesis is raised on the use of reduced glutathione (GSH) or N-Acetyl Cysteine as it may be an added adjuvant in the combination of 5- FU and L-Arginine for management of BAC.

Berberine ameliorates lipopolysaccharide-induced acute lung injury via the PERK-mediated Nrf2/HO-1 signaling axis.

A fundamental element of acute lung injury (ALI) is the inflammatory response, which can affect the entire respiratory system, including the respiratory tract and alveoli. Berberine has gained attention because of its anti-inflammatory effects. Nuclear factor-erythroid 2-related factor 2 (Nrf2) and endoplasmic reticulum (ER) stress are involved in lung injury. Nrf2 also acts as a protein kinase-like ER kinase (PERK) substrate in heart disease. Therefore, this study investigated the effect of berberine against lipopolysaccharide (LPS)-induced ALI and the role of the PERK-mediated Nrf2/HO-1 signaling axis. Berberine promoted Nrf2 nuclear translocation and phosphorylation in vitro. After LPS stimulation, this effect was further enhanced, whereas inflammatory factor (IL-6 and IL-8) release and reactive oxygen species generation were significantly decreased. Berberine effectively alleviated lung injury by reducing lung edema and neutrophil infiltration. Berberine also significantly reduced histopathological inflammatory changes via inhibition of ER stress and activation of Nrf2 signaling. Thapsigargin-induced ER stress and small interference RNA (siRNA)-mediated Nrf2 inhibition abrogated the protective effects of berberine in vitro, whereas siRNA-mediated suppression of ER stress and sulforaphane-induced Nrf2 activation further improved those effects. Importantly, ER stress induction led to Nrf2 activation, whereas PERK depletion partly reduced the level of Nrf2 phosphorylation and translocation in LPS-induced cells. Therefore, berberine inhibits LPS-induced ALI through the PERK-mediated Nrf2/HO-1 signaling axis.

Safety and efficacy of aged garlic extract in dogs: upregulation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and Nrf2-regulated phase II antioxidant enzymes.

BACKGROUND: Plants of Allium spp., including garlic (A. sativum) and onions (A. cepa), are known to be oxidatively toxic to canine erythrocytes resulting in Heinz body hemolytic anemia in dogs. In humans, these plants have been used as medicinal agents for multiple diseases since ancient times. Especially, fresh garlic extracted over a prolonged period produces less irritative and odorless aged garlic extract (AGE), containing unique and beneficial organosulfur compounds that can help prevent many kinds of diseases. In this study, the safety and efficacy of long-term oral administration of AGE is evaluated in dogs. The objectives are to confirm the safe dosage for long-term use and beneficial functions of AGE for dogs and to plan and design a canine health supplement or a preventive agent for multiple diseases based on the data of this study. RESULTS: Beagles were orally administered AGE (45 or 90 mg/kg body weight once a day) or an equivalent amount of water as control for 12 weeks. In AGE-treated groups, at 12 weeks post-administration at a dose of 90 mg/kg, there were no observable changes in the clinical signs, complete blood count, and serum biochemical parameters. Heinz bodies and eccentrocytes, the markers of oxidative damage in erythrocytes, did not appear in blood smear examination. In order to further evaluate the beneficial effects of AGE on health of dogs, the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) gene (NFE2L2) and Nrf2-regulated phase II antioxidant enzyme genes (NQO1, GCLM, HMOX1, and SOD2) were determined in whole blood between pre- and post-AGE administration. The expression of NFE2L2 gene was significantly upregulated in the AGE-treated groups [45 (p < 0.05) and 90 mg/kg (p < 0.01), 8 weeks] as compared to in the control group. Among the Nrf2-regulated enzymes examined, the expressions of NQO1 [45 (p < 0.05) and 90 mg/kg (p < 0.01), 8 weeks] and GCLM [45 (p < 0.05) and 90 mg/kg (p < 0.01), 12 weeks] genes were significantly upregulated. CONCLUSION: The long-term oral administration of AGE at a dose of 90 mg/kg/day for 12 weeks did not show any adverse effects in dogs. Furthermore, the administration of AGE upregulated the gene expressions of canine Nrf2 and Nrf2-regulated phase II antioxidant enzymes. These results suggest that AGE might safely contribute to the health of dogs provided that the appropriate dosage is used.

Spatholobus suberectus Ameliorates Diabetes-Induced Renal Damage by Suppressing Advanced Glycation End Products in db/db Mice.

Spatholobus suberectus (SS) is a medicinal herb commonly used in Asia to treat anemia, menoxenia and rheumatism. However, its effect of diabetes-induced renal damage and mechanisms of action against advanced glycation end-products (AGEs) are unclear. In this study, we evaluated the effects of SS on diabetes-induced renal damage and explored the possible underlying mechanisms using db/db type 2 diabetes mice. db/db mice were administered SS extract (50 mg/kg) orally for 6 weeks. SS-treated group did not change body weight, blood glucose and glycated hemoglobin (HbA1c) levels. However, SS treatment reversed diabetes-induced dyslipidemia and urinary albumin/creatinine ratio in db/db mice. Moreover, SS administration showed significantly increased protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2), which is a transcription factor for antioxidant enzyme. SS significantly upregulated glyoxalase 1 (Glo1) and NADPH quinine oxidoreductase 1 (NQO1) expression but reduced CML accumulation and downregulated receptor for AGEs (RAGE). Furthermore, SS showed significant decrease of periodic acid⁻Schiff (PAS)-positive staining and AGEs accumulation in histological and immunohistochemical analyses of kidney tissues. Taken together, we concluded that SS ameliorated the renal damage by inhibiting diabetes-induced glucotoxicity, dyslipidemia and oxidative stress, through the Nrf2/antioxidant responsive element (ARE) stress-response system.

Oxidative stress-elicited YY1 potentiates antioxidative response via enhancement of NRF2-driven transcriptional activity: A potential neuronal defensive mechanism against ischemia/reperfusion cerebral injury.

Cerebral ischemia challenge evokes an adaptive defensive system through the induction of antioxidant enzymes. Many of such antioxidant enzymes are regulated essentially by the nuclear factor erythroid 2-related factor-2 (NRF2). Compelling evidence supports that targeting NRF2 signaling is a promising therapeutic strategy to alleviate post-I/R brain injury, but the molecular mechanisms underlying this strategy have yet to be elucidated. Herein, we show that the expression of transcription factor Yin Yang 1 (YY1) is significantly upregulated during the recovery following middle cerebral artery occlusion (MCAO). Ablation of endogenous YY1 using cerebral ventricle injection of siRNA exacerbated I/R-induced neuronal damage and attenuated the antioxidant defensive system. Mechanistically, low levels of reactive oxygen species (ROS) production stimulated neuronal YY1 expression, whereas high levels of ROS exhibited a noticeable inhibitory effect. The evoked YY1, in concert with other coregulators, recruited to the antioxidant responsive elements (AREs) binding site and then amplified the NRF2-mediated ARE transcription, thereby protecting cells against damage by potentiating antioxidant response. In this regard, compromise of YY1 expression by ROS overactivity is an important etiology that sabotages the antioxidant defensive system and consequently deteriorate s neuronal damage following I/R injury. Taken together, our findings provide novel evidence on a delicate and synergistical collaboration between YY1 and the master transcription factor NRF2 that functions to mobilize the cell's antioxidant machinery.