A protective role of nuclear factor-erythroid 2-related factor-2 (Nrf2) in inflammatory disorders

Cardamonin Reduces Acetaminophen-Induced Acute Liver Injury in Mice via Activating Autophagy and NFE2L2 Signaling

Cardamonin (CD), a naturally occurring chalcone derived from the Alpinia species, has been shown to exert antioxidant and anti-inflammatory activity, but its role in the prevention of acetaminophen- (APAP-) induced hepatotoxicity remains elusive. The objective of this study was to determine the protective effects of CD against APAP-induced acute liver injury (ALI) and the underlying mechanisms. Wild-type or transcription factor nuclear factor erythroid 2-related factor 2- (NFE2L2-) deficient mice were treated with CD (50 or 100 mg/kg, i.p.) or vehicle for 24 h. Subsequently, these mice were challenged with APAP (400 mg/kg, i.p.) for 6 h. Liver and blood samples were collected to evaluate liver injury and protein abundance. Treatment with CD significantly reduced APAP-induced hepatotoxicity. Furthermore, CD effectively reduced APAP-induced inflammation by inhibiting high mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), and NOD-like receptor protein 3 (NLRP3) signaling. In addition, CD induced activation of sequestosome 1 (p62) and NFE2L2 signaling and facilitated autophagy. By applying autophagy inhibitor 3-methyladenine (3-MA; 20 mg/kg, i.p.), further mechanistic exploration revealed that NFE2L2 deficiency promoted autophagic activity induced by CD treatment, which was conducive to the hepatoprotective effect of CD against APAP-induced hepatoxicity in NFE2L2^−/− mice. Overall, data suggest that CD has hepatoprotective effect against APAP-induced ALI, which might contribute to the activation of NFE2L2 and autophagy.

Biochanin A alleviates gingival inflammation and alveolar bone loss in rats with experimental periodontitis

Biochanin A (BA) is an organic compound produced by Trifolium pretense and Arachis hypogaea with anti-inflammatory and antioxidative effects. The aim of the current study was to evaluate the effects of BA on gingival inflammation and alveolar bone destruction in rats with experimental periodontitis. Experimental rats (n=25) were distributed equally into five groups: i) Healthy control (control) group; ii) experimental periodontitis (ligation) group; and iii) and ligation plus low, medium and high dose of BA (12.5, 25 and 50 mg/kg/day, respectively) groups. A nylon ligature was inserted around rats' maxillary molars for 14 days to trigger the experimental periodontitis. BA was intravenous injected once daily for 4 weeks. After that, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), reactive oxygen species (ROS) and osteocalcin (OCN) levels were determined in gingival and/or serum samples using ELISA or reverse transcription-quantitative PCR. Alveolar bone volume was assessed via hematoxylin and eosin staining and micro-computed tomography. Osteoclasts were identified by tartrate-resistant acid phosphatase staining, and the level of the nuclear factor erythroid-2 related factor 2 (Nrf2) was also detected by immunohistochemical staining. BA treatment groups showed alleviated alveolar bone resorption compared with the ligation group. Moreover, BA treatment significantly inhibited IL-1β, TNF-α, ROS levels, and reduced leukocyte acid phosphatase-positive cells, as well as increased OCN and Nrf2 levels compared with the ligation group. BA had beneficial effects on experimental periodontitis of rats. BA treatment inhibited inflammation, regulated unbalanced oxidative stress response and ameliorated the alveolar bone loss.

Effect of di(2-ethylhexyl) phthalate on Nrf2-regulated glutathione homeostasis in mouse kidney

Environmental toxicants such as phthalate have been involved in multiple health disorders including renal diseases. Oxidative damage is implicated in many alterations caused by phthalate especially the di(2-ethylhexyl) phthalate (DEHP), which is the most useful phthalate. However, information regarding its mechanism of renal damage is lacking. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates gene expression implicated in free radical scavenging and cytoprotection including the antioxidant glutathione (GSH) pathway. The aim of this study was to assess whether DEHP affects the Nrf2 pathway and the GSH concentration. Mice were divided into four groups: a control group and three groups treated with DEHP at different concentrations (5, 50, and 200 mg/kg body weight) for 30 days. Our results showed that DEHP altered the normal levels of serum biochemical parameters creatinine (CREA), urea, and lactate dehydrogenase (LDH). This phthalate caused oxidative damage through the induction of lipid peroxidation and protein oxidation as marked by increase of protein carbonyl (PC) and loss of protein-bound sulfhydryls (PSH). Simultaneously, DEHP treatment decreased the protein level of Nrf-2, HO-1, and GCLC (responsible of GSH synthesis) and decreased the GSH level. Inhibition of the Nrf2 pathway is related to the activation of the mitochondrial pathway of apoptosis. This apoptotic process is evidenced by an upregulation of p53 and Bax protein levels in addition to a downregulation of Bcl-2. Collectively, our data demonstrated that depletion of Nrf2 and GSH was associated with the elevation of oxidative stress and the activation of intrinsic apoptosis in mouse kidney treated with DEHP.

Anti‑inflammatory effects of leaf and branch extracts of honeyberry (Lonicera caerulea) on lipopolysaccharide‑stimulated RAW264.7 cells through ATF3 and Nrf2/HO‑1 activation

Honeyberry (Lonicera caerulea) has long been used as a traditional medicine in China, Japan and northern Russia. Functional studies of honeyberry have mainly focused on the fruits, which have been reported to exert various pharmacological activities, including anti-inflammatory activity, with limited or no studies on the other parts of the plant, such as the leaves and branches. In the present study, the anti-inflammatory effects of extracts of the leaves (HBL), branches (HBB) and fruit (HBF) of honeyberry plant were evaluated in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. HBL and HBB significantly inhibited the production of pro-inflammatory mediators in LPS-stimulated RAW264.7 cells, and the inhibitory effects of HBL and HBB were stronger than those of HBF. HBL and HBB blocked the nuclear accumulation of p65 independently of IκB-α. HBL did not inhibit the phosphorylation of ERK1/2 or p38; however, HBB effectively inhibited the phosphorylation of p38 but not ERK1/2. HBL and HBB increased the expression of heme oxygenase-1 (HO-1) protein by inducing the nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) through the activation of the reactive oxygen species (ROS)/p38 pathway; the reduction in inducible nitric oxide synthase (iNOS) and interleukin-1β (IL-1β) expression by HBL and HBB was inhibited by HO-1 knockdown. In addition, HBL and HBB increased the expression of activating transcription factor-3 (ATF3), and the reduction in iNOS and IL-1β expression by HBL and HBB was inhibited by ATF3 knockdown. Collectively, HBL and HBB inhibited LPS-induced nuclear factor-κB activation by blocking the nuclear accumulation of p65, increasing HO-1 expression through activation of the ROS/p38/Nrf2 pathway, and increasing ATF3 expression. Furthermore, HBB inhibited LPS-induced p38 phosphorylation. These findings suggest that HBL and HBB may have great potential as natural products for the development of anti-inflammatory drugs.

The Nrf2 in the pathophysiology of the intestine: Molecular mechanisms and therapeutic implications for inflammatory bowel diseases

Nrf2 (nuclear factor erythroid 2-related factor 2) is a stress-responsive transcription factor, associated with cellular homeostasis. Under normal conditions Nrf2 is kept in the cytoplasm by Kelch-like ECH-associated protein 1 (Keap1) which facilitates its degradation. Meanwhile, oxidative or electrophilic stress trigger Keap1 dissociation from the Nrf2/Keap1 complex and Nrf2 translocation to the nucleus where it induces the expression of numerous anti-oxidative and anti-inflammatory genes. The Nrf2/Keap1 axis plays a crucial role in the development of gastrointestinal (GI) tract and the maintenance of its proper functionality. This axis also seems to be a promising candidate for prevention of inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), as well as their severe complications such as intestinal fibrosis and colorectal cancer. This review focuses on the role of Nrf2/Keap1 in 1) the development and proper functionality of GI tract, 2) the pathophysiology of GI diseases and their long-term complications, 3) the effectiveness of currently used drugs and non-conventional treatments which influence Nrf2/Keap1 and are potentially effective in IBD treatment, as well as 4) the effect of gut microbiota on Nrf2/Keap1 pathway in IBD.

17β-Estradiol strongly inhibits azoxymethane/dextran sulfate sodium-induced colorectal cancer development in Nrf2 knockout male mice

Nuclear factor erythroid 2-related factor 2 (Nrf2) has dual effects on inflammation and cancer progression depending on the microenvironment. Estrogens have a protective effect on colorectal cancer (CRC) development. The aim of this study was to investigate CRC development in Nrf2 knockout (KO) mice. Azoxymethane (AOM) and dextran sulfate sodium (DSS)-treated wild-type (WT) and Nrf2 KO male mice were sacrificed at weeks 2 and 16 after AOM injection with/without 17β-estradiol (E2) treatment during week 1. Disease activity index and colon tissue damage at week 2 showed strong attenuation following E2 administration in WT mice but to a lesser extent in Nrf2 KO male mice. At week 16, E2 significantly diminished AOM/DSS-induced adenoma/cancer incidence at distal colon in the Nrf2 KO group, but not in the WT. Furthermore, mRNA or protein levels of NF-κB-related mediators (i.e., iNOS, TNF-α, and IL-1β) and Nrf2-related antioxidants (i.e., NQO1 and HO-1) were significantly lower in the Nrf2 KO group regardless of E2 treatment compared to the WT. The expression of estrogen receptor beta (ERβ) was higher in the Nrf2 KO group than in the WT. In conclusion, estrogen further inhibits CRC by upregulating ERβ-related alternate pathways in the absence of Nrf2.

Beneficial Effects of Naringenin in Cigarette Smoke-Induced Damage to the Lung Based on Bioinformatic Prediction and In Vitro Analysis

Naringenin is found mainly in citrus fruits, and is thought to be beneficial in the prevention and control of lung diseases. This study aims to investigate the mechanisms of naringenin against the damage in the lung caused by cigarette smoke. A system bioinformatic approach was proposed to predict the mechanisms of naringenin for protecting lung health. Then, we validated this prediction in BEAS-2B cells treated with cigarette smoke extract (CSE). System bioinformatic analysis indicated that naringenin exhibits protective effects on lung through the inhibition of inflammation and suppression of oxidative stress based on a multi-pathways network, mainly including oxidative stress pathway, Nrf2 pathway, Lung fibrosis pathway, IL-3 signaling pathway, and Aryl hydrocarbon receptor pathway. The in vitro results showed that naringenin significantly attenuated CSE-induced up-regulation of IL-8 and TNF-α. CSE stimulation increased the mRNA expressions of Nrf2, HO-1, and NQO1; the levels of total protein and nuclear protein of Nrf2; and the activity of SOD on days 2 and 4; but decreased these indexes on day 6. Naringenin can balance the antioxidant system by regulating Nrf2 and its downstream genes, preliminarily validating that Nrf2 pathway is involved in the protection offered by naringenin against cigarette smoke-induced damage to the lung. It suggests that dietary naringenin shows possible potential use in the management of lung health.

Changes in the Nrf2/Keap1 Ratio and PON1 Concentration in Plasma of Patients Undergoing the Left Main Coronary Artery Stenting

Nuclear factor erythroid 2-related factor2 (Nrf2), together with its inhibitor Kelch-like ECH-associated protein 1 (Keap1), is a crucial regulator of cellular redox response. Nrf2 binds to the antioxidant response element (ARE) present in the DNA sequence of a broad group of antioxidant compounds, including paraoxonase (PON1), inducing their transcription. This study was to answer the question of the effect of temporary ischemia/oxidative stress resulting from the left main stenting via percutaneous coronary intervention (LMPCI) performed in the patients included in this study on the cellular redox balance, which is guarded by the Nrf2/Keap1 interaction. We expected a reflection of the redox imbalance due to reactive oxygen species (ROS) in the change in PON1 concentration observed in the following stages of the study, as well as in total antioxidant capacity (TAC) levels. Our results showed the mobilization of cellular Nrf2/Keap1 team right after the procedure (pre-LMPCI median: 2.532, range: 0.07-11.88; post-LMPCI median: 3.735, range: 0.1545-16.18; 24 h-LMPCI median: 5.596, range: 0.02-49.18), which suggest being the result of oxidative stress that accompanies percutaneous coronary intervention (PCI). The course of Keap1 and Nrf2 concentrations at all stages of the experiment appeared to show that Keap1 shadowed the Nrf2 to switch off its activity after Nrf2 induced the mobilization of the antioxidant response. We observed an increase in PON1 concentration (pre-LMPCI median: 179.3, range: 49.76-6120; post-LMPCI median: 215.7, range: 3.80-2771) and a decrease in the TAC level immediately after PCI (pre-LMPC: $1.008\pm 0.27\text{I}$ , post-LMPCI: $0.8030\pm 0.27$ ). This study design allowed for the first time to analyze the chronology of mechanisms and the relationship between selected parameters reflecting the redox state in patients’ plasma. We may conclude that ischemia induced by the PCI was the source of imbalance in the Nrf2/Keap1 ratio via oxidative stress, and this leads to an increase in PON1 concentration first and, in the next step, the TAC mobilization.

Liver Transcriptome Responses to Heat Stress and Newcastle Disease Virus Infection in Genetically Distinct Chicken Inbred Lines

Heat stress results in reduced productivity, anorexia, and mortality in chickens. The objective of the study was to identify genes and signal pathways associated with heat stress and Newcastle disease virus (NDV) infection in the liver of chickens through RNA-seq analysis, using two highly inbred chicken lines (Leghorn and Fayoumi). All birds were held in the same environment until 14 days of age. On day 14, half the birds were exposed to 38 °C with 50% relative humidity for 4 h, then 35 °C until the end of the experiment. The remaining birds were kept at 25 °C throughout the experiment. The heat-treated birds were inoculated at 21 days of age with 107 EID50 (One EID50 unit is the amount of virus that will infect 50 percent of inoculated embryos) NDV La Sota strain to investigate the effects of both heat stress and NDV infection. Physiological parameters were recorded as blood phenotypes at three stages: acute heat (AH), chronic heat (CH1), and chronic heat combined with NDV infection (CH&NDV), at 4 h, 7 days, and 10 days post-initiation of heat treatment, respectively. Our previous work revealed that the heat-resilient Fayoumi line maintained a more stable acid-base balance in their blood compared to the Leghorn line. Liver samples were harvested on both AH and CH&NDV to characterize the transcriptome profiles of these two inbred lines. Both genetic lines and treatments had large impact on the liver transcriptome. Fayoumi birds had more differentially expressed genes (DEGs) than Leghorn birds for both treatments. Metabolic and immune-related genes were on the DEG list, with Fayoumi having more immune-related DEGs than Leghorns, which was confirmed by gene functional enrichment analysis. Weighted correlation network analysis (WGCNA) indicated that the driver genes such as Solute Carrier Family genes could be very important for stabilizing the acid-base balance in Fayoumi birds during heat stress. Therefore, candidate genes such solute carrier family genes could be potential genetic targets that are regulated by Fayoumis to maintain physical hemostasis under heat stress. Differential gene expression showed that Leghorns mainly performed metabolic regulation in response to heat stress and NDV infection, while Fayoumis regulated both immune and metabolic functions. This study provides novel insights and enhances our understandings of liver response to heat stress of heat resilient and susceptible inbred chicken lines.

Synergistic antioxidant effects of phenolic acids and carotenes on H2O2-induced H9c2 cells: Role of cell membrane transporters

Phenolic acids (caffeic acid, p-coumaric acid,) and carotenes (β-carotene, lycopene) were mixed in different ratios to investigate antioxidant interactions on H₂O₂-induced H9c2 cells with ezetimibe (inhibitor of carotenes membrane transporters). Cellular uptake of carotenes, expression of membrane transporters, reactive oxygen species (ROS), nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H dehydrogenase quinone1 (NQO1), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC) were analyzed. Results revealed that phenolic acids increased cellular uptake of carotenes and expression of their membrane transporters. Combination groups contained more phenolic acids showed synergistic effects. For example, β-carotene: caffeic acid = 1:2 significantly suppressed the intracellular ROS (+EZT, 66.34 ± 51.53%) and enhanced the accumulation of nucleus-Nrf2 (+EZT, 30.23 ± 5.30) compared to the groups contained more β-carotene (+EZT, ROS: 75.48 ± 2.55%, nucleus-Nrf2: 19.48 ± 4.22). This study provided an implication of functional foods formulation and demonstrated that antioxidant synergism may due to the up-regulation of carotenes membrane transporters by phenolic acids.

NRF-2 and nonalcoholic fatty liver disease

Currently, chronic liver diseases have conditioned morbidity and mortality, many of these with a metabolic, toxicologic, immunologic, viral, or other etiology. Thus, a transcription factor that has been of huge importance for biomedical research is NRF-2. The latter is considered a principal component of the antioxidant mechanism, and it has been acknowledged that it impairs the function of NRF-2 in many liver diseases and that it forms an essential part of the pathologic changes that occur in the liver to contain inflammation and damage. Within the investigations and experiments carried out, there are isolated drugs, many of them related to plants and natural extracts that possess antioxidant properties through the NRF-2 signaling pathway, or even involving the stimulation of the transcription target proteins of NRF-2. Notwithstanding all of these experimental findings, to date there is not sufficient clinical evidence to justify the use of NRF-2 in medical practice.

The role of carbon monoxide, heme oxygenase 1, and the Nrf2 transcription factor in the modulation of chronic pain and their interactions with opioids and cannabinoids

Chronic pain and its associated comorbidities are difficult to treat, even when the most potent analgesic compounds are used. Thus, research on new strategies to effectively relieve nociceptive and/or emotional disorders accompanying chronic pain is essential. Several studies have demonstrated the anti-inflammatory and antinociceptive effects of different carbon monoxide-releasing molecules (CO-RMs), inducible heme oxygenase 1 (HO-1), and nuclear factor-2 erythroid factor-2 (Nrf2) transcription factor activators in several models of acute and chronic pain caused by inflammation, nerve injury or diabetes. More recently, the antidepressant and/or anxiolytic effects of several Nrf2 transcription factor inducers were demonstrated in a model of chronic neuropathic pain. These effects are mainly produced by inhibition of oxidative stress, inflammation, glial activation, mitogen-activated protein kinases and/or phosphoinositide 3-kinase/phospho-protein kinase B phosphorylation in the peripheral and/or central nervous system. Other studies also demonstrated that the analgesic effects of opioids and cannabinoids are improved when these drugs are coadministered with CO-RMs, HO-1 or Nrf2 activators in different preclinical pain models and that these improvements are generally mediated by upregulation or prevention of the downregulation of µ-opioid receptors, δ-opioid receptors and/or cannabinoid 2 receptors in the setting of chronic pain. We reviewed all these studies as well as studies on the mechanisms of action underlying the effects of CO-RMs, HO-1, and Nrf2 activators in chronic pain. In summary, activation of the Nrf2/HO-1/carbon monoxide signaling pathway alone and/or in combination with the administration of specific analgesics is a valid strategy for the treatment of chronic pain and some associated emotional disorders.

Anthocyanins As Modulators of Cell Redox-Dependent Pathways in Non-Communicable Diseases

Chronic Noncommunicable Diseases (NCDs), mostly represented by cardiovascular diseases, diabetes, chronic pulmonary diseases, cancers, and several chronic pathologies, are one of the main causes of morbidity and mortality, and are mainly related to the occurrence of metabolic risk factors. Anthocyanins (ACNs) possess a wide spectrum of biological activities, such as anti-inflammatory, antioxidant, cardioprotective and chemopreventive properties, which are able to promote human health. Although ACNs present an apparent low bioavailability, their metabolites may play an important role in the in vivo protective effects observed. This article directly addresses the scientific evidences supporting that ACNs could be useful to protect human population against several NCDs not only acting as antioxidant but through their capability to modulate cell redox-dependent signaling. In particular, ACNs interact with the NF-κB and AP-1 signal transduction pathways, which respond to oxidative signals and mediate a proinflammatory effect, and the Nrf2/ARE pathway and its regulated cytoprotective proteins (GST, NQO, HO-1, etc.), involved in both cellular antioxidant defenses and elimination/inactivation of toxic compounds, so countering the alterations caused by conditions of chemical/oxidative stress. In addition, supposed crosstalks could contribute to explain the protective effects of ACNs in different pathological conditions characterized by an altered balance among these pathways. Thus, this review underlines the importance of specific nutritional molecules for human health and focuses on the molecular targets and the underlying mechanisms of ACNs against various diseases.

HJ22, a Novel derivative of piperine, Attenuates ibotenic acid-induced cognitive impairment, oxidativestress, apoptosis and inflammation via inhibiting the protein-protein interaction of Keap1-Nrf2

Kelch-like ECH-associated protein (Keap1)-nuclear factor erythroid-2-related factor 2 (Nrf2) protein-protein interaction has become an important drug target for the treatment of Alzheimer's disease. In this study, we found a novel piperine derivative (HJ22) synthesized by our group with great ability to bind to Keap-1 and activate Keap1-Nrf2-ARE signaling pathway in vitro, driving us to investigate the beneficial effects of HJ22 on ibotenic acid (IBO)-induced neurological disorders in rats and underlying mechanisms. Interestingly, HJ22 significantly ameliorated IBO-induced cognitive impairment in Morris water maze, Y-maze and passive avoidance tests. Moreover, HJ22 significantly attenuated cholinergic dysfunction and neuronal morphological changes via inhibiting apoptotic cell death induced by IBO. Notably, HJ22 inhibited the interaction between Keap1 and Nrf2, and subsequently up-regulated nuclear Nrf2 expression, thereby inhibiting oxidative stress and Thioredoxin-interacting protein (TXNIP)-mediated Nod-like receptor protein 3 (NLRP3) inflammasome activation. These findings demonstrated that HJ22 exhibited potent therapeutic effects against IBO-induced cognitive impairment by alleviating cholinergic damage, oxidative stress, apoptosis and neuroinflammation, which might be partly attributed to its inhibitory activity on Keap1-Nrf2 protein-protein interaction.

Long Noncoding RNA MEG3 Inhibits Apoptosis of Retinal Pigment Epithelium Cells Induced by High Glucose via the miR-93/Nrf2 Axis

Diabetic retinopathy (DR) is the leading cause of visual impairment in developed nations. Though plasma microRNA-93 (miR-93) is associated with the risk of DR, the function and regulatory mechanism of miR-93 during DR remains unclear. Blood samples were collected from 12 DR patients and 12 healthy controls. Primary human retinal pigment epithelium (RPE) cells and ARPE-19 cells were cultured in 5 mmol/L or 33 mmol/L d-glucose medium. Long noncoding (lnc) RNA MEG3 and miR-93 expression was detected by real-time quantitative PCR. The effect of MEG3 and miR-93 on high glucose (HG)-induced apoptosis was detected by MTT and flow cytometry. IL-6 and tumor necrosis factor-α levels were detected by enzyme-linked immunosorbent assay. The relationships among MEG3, miR-93, and Nrf2 (also known as NFE2L2) were explored via dual-luciferase reporter assay. lncRNA MEG3 and Nrf2 were decreased and miR-93 was increased in blood samples of DR patients and HG-treated human RPE and ARPE-19 cells. Overexpression of miR-93 inhibited cell proliferation and promoted apoptosis, whereas overexpression of Nrf2 or MEG3 promoted proliferation and suppressed apoptosis and inflammation. In addition, MEG3 targeted miR-93 and down-regulated miR-93. Moreover, miR-93 directly targeted Nrf2 and negatively regulated Nrf2. This study suggests that lncRNA MEG3 depresses HG-induced apoptosis and inflammation of RPE via miR-93/Nrf2 axis, providing a novel perspective on the genesis and development of DR.

Evaluation of the role of Nrf2/Keap1 pathway-associated novel mutations and gene expression on antioxidant status in patients with deep vein thrombosis

Deep vein thrombosis (DVT) is a type of venous thromboembolism and a clinically complex vascular disease. Oxidative stress serves a key role in the pathogenesis of numerous cardiovascular diseases, particularly in endothelial dysfunction-associated syndromes. Nuclear factor erythroid-2-like 2(Nrf2) transcription factor is the primary regulator of antioxidant responses. The levels of reactive oxygen species (ROS) are regulated by Nrf2 and its suppressor protein Kelch-like ECH-associated protein 1 (Keap1). However, to the best of our knowledge, genetic abnormalites in the Nrf2/Keap1 pathway in DVT syndrome have not been thoroughly investigated. The aim of the present study was to investigate the association between the Nrf2/Keap1 pathway and antioxidant responses in DVT. Mutations and expression levels of genes involved in the Nrf2/Keap1 pathway were measured in 27 patients with DVT via DNA sequencing analysis and reverse transcription-quantitative PCR, respectively. The Polymorphism Phenotyping v2 program was used to identify the pathogenic mutations. Total antioxidant activity levels were determined by measuring the effect of serum samples from 27 patients with DVT on oxidation of the 2,2'-azino-bis (3-ethylbenz-thiazoline-6-sulfonic acid) system. A total of 23 mutations, including seven novel mutations, were detected in the Nrf2/Keap1 pathway in 24 (89%) of the 27 patients with DVT. Keap1 mRNA expression levels were significantly higher compared with Nrf2 expression levels in patients with DVT (P=0.02). Analysis of molecular characteristics and gene expression levels demonstrated that Nrf2/Keap1-associated mutations and total antioxidant levels can be used as precursor markers in the diagnosis of DVT.

MiR-27b-3p exerts tumor suppressor effects in esophageal squamous cell carcinoma by targeting Nrf2

MiR-27b-3p has been reported to function as tumor suppressor in several tumors, including breast cancer and lung cancer. Recently, miR-27b-3p has been identified to be significantly down-regulated in esophageal cancer. However, the clinical significance and biological role of miR-27b-3p in esophageal squamous cell carcinoma (ESCC) still remain unclear. In this study, the expression levels of miR-27b-3p were significantly reduced in ESCC clinical tissues and ESCC cell lines (EC97069 and TE-1). Moreover, down-regulated expression of miR-27b-3p was associated with poor cell differentiation, TNM stage and lymph node metastasis. Specially, overexpression of miR-27b-3p significantly suppressed cell proliferation, migration and invasion in vitro using CCK-8 and transwell assays. Targetscan bioinformatics predictions and luciferase reporter assay confirmed that nuclear factor erythroid 2-related factor 2 (NFE2L2, Nrf2) was a direct target gene of miR-27b-3p. Nrf2 expression was significantly increased in ESCC tissues compared with adjacent tissues. Up-regulated expression of Nrf2 was correlated with TNM stage and lymph node metastasis. Functionally, knockdown of Nrf2 exhibited similar effects to overexpression of miR-27b-3p. Higher expression of ZO-1, E-cadherin and lower expression of N-cadherin, Vimentin and Claudin-1 were observed after miR-27b-3p overexpression of Nrf2 knockdown. Rescue experiments proved that miR-27b-3p suppressed cell proliferation, migration, invasion and epithelial to mesenchymal transition (EMT) via suppression of Nrf2. Taken together, the newly identified miR-27b-3p/Nrf2 axis might represent a new candidate therapeutic target for ESCC treatment.

UVA Induced Oxidative Stress Was Inhibited by Paeoniflorin/Nrf2 Signaling or PLIN2

Photodamages caused by UVA radiation induced oxidative injuries are closely related to photoaging and skin cancer. Paeoniflorin (PF), extracted from the root of Paeonia lactiflora, has been reported to be an effective antioxidant. PLIN2, known as adipose differentiation-related protein, has been previously involved in the regulation of oxidative stress. In this study, we were sought to investigate the photo-protective property of PF and PLIN2 in UVA-radiated human dermal fibroblasts (HDFs). HDFs were pre-treated with PF (800 μM) followed by UVA radiation (22.5 J/cm2). MTS activity, cell apoptosis, ROS, MDA, and SOD were detected, respectively. The expressions of Nrf2, HO-1, NQ-O1, and PLIN2 were determined using RT-qPCR or western blot. Nrf2 was silenced by siRNA, and PLIN2 was overexpressed via lentiviral transduction. Comparing to the UVA radiation, PF pre-treatment could prominently increase the MTS activity, decrease cell apoptosis, reduce the generations of ROS and MDA, increase the activity of SOD and increase the expression of Nrf2 and its target genes HO-1 and NQ-O1. When Nrf2 was knocked down, PF lost above protective properties. In addition, UVA induced oxidative stress led to upregulation of PLIN2 and the latter could be decreased by PF. Overexpression of PLIN2 improved MTS activity and reduced MDA level in HDFs. The combination of PLIN2 overexpression and PF pre-treatment corporately inhibited UVA-induced injury. Besides, we also found that PF and PLIN2 had a compensatory protection against UVA induced oxidative stress. In conclusion, our study demonstrated that UVA induced photodamages could be inhibited by PF via Nrf2/HO-1/NQ-O1 signaling pathway or by PLIN2, and the combination of PLIN2 overexpression and PF played additive effects against UVA-related oxidative stress.

Protective role of Nrf2 against ischemia reperfusion injury and cardiac allograft vasculopathy

Ischemia-reperfusion injury (IRI) and cardiac allograft vasculopathy (CAV) remain unsolved complications post-heart transplant (Tx). The antioxidant transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2) has been suggested to inhibit reactive oxygen species-mediated NF-κB activation. We hypothesized that Nrf2 inhibits NF-κB activation post-Tx and suppresses IRI and the subsequent development of CAV. IRI and CAV were investigated in murine heterotopic Tx models, respectively. Nrf2 wild-type (WT) and KO mice were used as donors. Sulforaphane was used as an Nrf2 agonist. In saline-treated animals following 24 hours of reperfusion in isogenic grafts, Nrf2-KO showed significantly less SOD1/2 activity compared with WT. Nrf2-KO displayed significantly high total and phosphorylated p65 expressions and percentage of cells with nuclear p65. mRNA levels of NF-κB-mediated proinflammatory genes were also high. Graft dysfunction, apoptosis, and caspase-3 activity were significantly higher in Nrf2-KO. In the allograft studies, graft beating score was significantly weaker in Nrf2-KO compared with WT. Nrf2-KO also demonstrated significantly more coronary luminal narrowing. In WT animals, sulforaphane successfully augmented all the protective effects of Nrf2 with increase of SOD2 activity. Nrf2 inhibits NF-κB activation and protects against IRI via its antioxidant properties and suppresses the subsequent development of CAV.

Piperine ameliorated memory impairment and myelin damage in lysolecethin induced hippocampal demyelination

AIMS

We still do not have effective treatment for hippocampal demyelination and memory deficit, the two common comorbidities in multiple sclerosis (MS). This study aimed to assess the therapeutic effect of Piperine (the main alkaloid of black pepper) in an experimental model of demyelination.

MAIN METHODS

Demyelination was induced in male Wistar rats by bilateral injection of lysolecithin (LPC) into the CA1 region of the hippocampus. Piperine (5, 10, 20 mg/kg) was daily injected intraperitoneally three days post LPC injection for ten days. The spatial memory was examined by the Morris water maze task. Demyelination and astrocyte activation were assessed by an immunohistological study. The gene expression analysis of TNF-α, IL1-β, NF-κB, IL-10, Foxp3, iNOS, Nrf2, HO1, MBP, and BDNF was done using qPCR. The total antioxidant capacity of hippocampal tissue was measured using FRAP assay.

KEY FINDINGS

Our results showed that piperine improved the memory performance and myelin repair in the hippocampal demyelination model. Piperine inhibited iNOS expression concomitant with enhanced expression levels of Nrf2, HO1 and the total antioxidant capacity in the hippocampal tissue. Piperine treatment significantly reduced the gene expression level of TNF-α, IL1-β, NF-κB, and glial activation in the injured area; however, the mRNA level of IL-10, Foxp3, BDNF and MBP were significantly increased.

SIGNIFICANCE

We found piperine to be an effective treatment for spatial memory impairment and myelin repair in the hippocampal demyelination model. However, further experimental evidence is needed to investigate the precise mechanisms underlying piperine as a promising therapeutic target in MS patients.

Cytoprotective Effect of Ascorbic Acid and Rutin against Oxidative Changes in the Proteome of Skin Fibroblasts Cultured in a Three-Dimensional System

The combination of ascorbic acid and rutin, commonly used in oral preparations for their antioxidant and anti-inflammatory properties, can also be used to protect skin cells from the effects of UV radiation in sunlight. Here, we tested the potential protective effect of ascorbic acid and rutin used together in UVB-irradiated human skin fibroblasts, and assessed the proteomic profile of these cells, grown in a three-dimensional (3D) system. Proteomic findings revealed a combined effect of ascorbic acid and rutin in UV-irradiated fibroblasts against overexpression of pro-inflammatory signaling proteins and DNA reorganization/expression. These effects were not observed when cells were treated with either compounds alone. The antioxidant effects of ascorbic acid and rutin also prevented protein modifications by lipid peroxidation products. Further, ascorbic acid stimulated rutin-protein adduct formation, which supports intra/extracellular signaling and the Nrf2/ARE antioxidant pathway, contributing to the protective effects against UV-induced oxidative stress. The combined effect of ascorbic acid and rutin suggests that this combination of compounds is potentially effective against skin damage caused by UV radiation.

Anthocyanins reduce inflammation and improve glucose and lipid metabolism associated with inhibiting nuclear factor-kappaB activation and increasing PPAR-γ gene expression in metabolic syndrome subjects

Anthocyanins exhibit antioxidant and anti-inflammatory activities via a multitude of biochemical mechanisms. However, the signaling pathways involved in the actions of anthocyanins against chronic inflammation are not fully understood. The effects of berry-rich anthocyanin supplements (320 mg/day) for four weeks were examined on features of metabolic syndrome components and the expression of PPAR-γ, Nrf2, and NF-κB dependent genes in MetS and healthy subjects. Total RNA was isolated from whole blood with the PAXgene proprietary blood collection system. Four weeks anthocyanin consumption significantly decreased fasting blood glucose (15.7% vs 3.2%), TG (18.2% vs -1.39%), cholesterol (33.5% vs 1.56%) and LDL (28.4% vs -15.6%) in the MetS compared to Control group (P-value < 0.05, 95% CI). There was a significant up regulation in the expression PPAR-γ gene associated with the lipid and glucose metabolism in MetS subjects which negatively correlated (P-value < 0.01) with the change in the FBG (r = -0.488), Cholesterol (r = -0.496), TG (r = -0.513) and LDL (r = -0.519). Moreover, anthocyanin supplementation decreases serum hs-CRP (-36.3% vs 6.25%) in MetS in compared to Control group (P-value < 0.05). Anthocyanin supplementation also down-regulated the expression of NF-κB dependent genes including TNF-α (-28% and -15%), IL-6 (-16.1% and -13.6%), IL-1A (-21.5% and -12.9%), PCAM-1 (-15% and -17.5%), and COX-2(-26% and -27%) in both MetS and Control group respectively (P-value < 0.05). The study results suggested that berry supplements improved selected features of metabolic syndrome and related cardiovascular risk factors. These benefits may be due to the inhibition of NF-κB dependent gene expression and enhancement of PPAR-γ.

Influence of different oil sources on growth, disease resistance, immune response and immune-related gene expression on the hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu), to Vibrio parahaemolyticus challenge

The aim of this study was to investigate the effects of feeding alternative dietary oils to hybrid grouper fish (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) on their growth, histological morphology of hepatocytes, disease resistance, immune response, and expression of immune-related genes. Seven experimental fish meal-based isonitrogenous and isolipidic diets were formulated containing 5% fish oil (FO; acting as controls) and various vegetable oils (VOs): corn oil (CO), sunflower oil (SO), tea oil (TO), olive oil (OO), rice oil (RO), and mixed oil (MO); comprising equal amounts of these oils). Each diet was fed to triplicate groups of 40 fish (initial mean body weight ± standard error = 15.09 ± 0.01 g) for eight weeks. The results show that 1) alternative dietary oils had no significant effects on weight gain rate, specific growth rate, protein efficiency ratio, and survival rate compared with controls (P > 0.05). The weight gain rate (WGR) and specific growth rate (SGR) of the SO group were lower than in the CO and OO groups. 2) These were no differences in morphological indexes among groups; except for the CO group, in which the condition factor and hepatosomatic index were lower than those in other groups. 3) Compared with controls, the whole-body moisture and crude protein contents in the VO groups were higher, while their crude lipid contents were lower. 4) The fatty acid contents in liver and muscle were affected by lipid type, and the contents of eicosapentaenoic acid and docosahexaenoic acid in liver and muscle in the VO groups were markedly lower than in controls. 5) Compared with control group, VO groups damaged the histological morphology of hepatocytes. 6) After a challenge with the Vibrio parahaemolyticus bacterium, there were no differences in mortality among groups. However, VO enhanced the activity of non-specific immune enzymes while down-regulating the expression of Nrf2 and inducing the expression of pro-inflammatory factors (IL1β, TNFα, TLR22, and MyD88) in the kidney. It can be concluded that dietary VO substitution does not affect the growth of fish but damaged the histological morphology of hepatocytes and induced the expression of pro-inflammatory factors in tissues. Finally, OO and CO were recommended as the appropriate lipid replacement for FO.

Oxidative and Inflammatory Events in Prion Diseases: Can They Be Therapeutic Targets?

Prion diseases are a group of incurable infectious terminal neurodegenerative diseases caused by the aggregated misfolded PrPsc in selected mammals including humans. The complex physical interaction between normal prion protein PrPc and infectious PrPsc causes conformational change from the α- helix structure of PrPc to the β-sheet structure of PrPsc, and this process is repeated. Increased oxidative stress is one of the factors that facilitate the conversion of PrPc to PrPsc. This overview presents evidence to show that increased oxidative stress and inflammation are involved in the progression of this disease. Evidence is given for the participation of redoxsensitive metals Cu and Fe with PrPsc inducing oxidative stress by disturbing the homeostasis of these metals. The fact that some antioxidants block the toxicity of misfolded PrPc peptide supports the role of oxidative stress in prion disease. After exogenous infection in mice, PrPsc enters the follicular dendritic cells where PrPsc replicates before neuroinvasion where they continue to replicate and cause inflammation leading to neurodegeneration. Therefore, reducing levels of oxidative stress and inflammation may decrease the rate of the progression of this disease. It may be an important order to reduce oxidative stress and inflammation at the same time. This may be achieved by increasing the levels of antioxidant enzymes by activating the Nrf2 pathway together with simultaneous administration of dietary and endogenous antioxidants. It is proposed that a mixture of micronutrients could enable these concurrent events thereby reducing the progression of human prion disease.

Hepatic transcriptome of the freeze-tolerant Cope's gray treefrog, Dryophytes chrysoscelis: responses to cold acclimation and freezing

Background

Cope’s gray treefrog, Dryophytes chrysoscelis, withstands the physiological challenges of corporeal freezing, partly by accumulating cryoprotective compounds of hepatic origin, including glycerol, urea, and glucose. We hypothesized that expression of genes related to cryoprotectant mobilization and stress tolerance would be differentially regulated in response to cold. Using high-throughput RNA sequencing (RNA-Seq), a hepatic transcriptome was generated for D. chrysoscelis, and gene expression was compared among frogs that were warm-acclimated, cold-acclimated, and frozen.

Results

A total of 159,556 transcripts were generated; 39% showed homology with known transcripts, and 34% of all transcripts were annotated. Gene-level analyses identified 34,936 genes, 85% of which were annotated. Cold acclimation induced differential expression both of genes and non-coding transcripts; freezing induced few additional changes. Transcript-level analysis followed by gene-level aggregation revealed 3582 differentially expressed genes, whereas analysis at the gene level revealed 1324 differentially regulated genes. Approximately 3.6% of differentially expressed sequences were non-coding and of no identifiable homology. Expression of several genes associated with cryoprotectant accumulation was altered during cold acclimation. Of note, glycerol kinase expression decreased with cold exposure, possibly promoting accumulation of glycerol, whereas glucose export was transcriptionally promoted by upregulation of glucose-6-phosphatase and downregulation of genes of various glycolytic enzymes. Several genes related to heat shock protein response, DNA repair, and the ubiquitin proteasome pathway were upregulated in cold and frozen frogs, whereas genes involved in responses to oxidative stress and anoxia, both potential sources of cellular damage during freezing, were downregulated or unchanged.

Conclusion

Our study is the first to report transcriptomic responses to low temperature exposure in a freeze-tolerant vertebrate. The hepatic transcriptome of Dryophytes chrysoscelis is responsive to cold and freezing. Transcriptomic regulation of genes related to particular pathways, such as glycerol biosynthesis, were not all regulated in parallel. The physiological demands associated with cold and freezing, as well as the transcriptomic responses observed in this study, are shared with several organisms that face similar ecophysiological challenges, suggesting common regulatory mechanisms. The role of transcriptional regulation relative to other cellular processes, and of non-coding transcripts as elements of those responses, deserve further study.

Pulmonary hypertension in chronic obstructive pulmonary disease

Even mild pulmonary hypertension (PH) is associated with increased mortality and morbidity in patients with chronic obstructive pulmonary disease (COPD). However, the underlying mechanisms remain elusive; therefore, specific and efficient treatment options are not available. Therapeutic approaches tested in the clinical setting, including long-term oxygen administration and systemic vasodilators, gave disappointing results and might be only beneficial for specific subgroups of patients. Preclinical studies identified several therapeutic approaches for the treatment of PH in COPD. Further research should provide deeper insight into the complex pathophysiological mechanisms driving vascular alterations in COPD, especially as such vascular (molecular) alterations have been previously suggested to affect COPD development. This review summarizes the current understanding of the pathophysiology of PH in COPD and gives an overview of the available treatment options and recent advances in preclinical studies. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc.

Cryptotanshinone from Salvia miltiorrhiza Bunge (Danshen) inhibited inflammatory responses via TLR4/MyD88 signaling pathway

Background

Cryptotanshinone (CPT), as a major component of Salvia miltiorrhiza Bunge (Danshen), displays many pharmacological activities including anti-inflammatory effects. However, the exact cellular and molecular mechanisms of the anti-inflammatory activities of CPT remain to be elucidated. The present study was aimed to clarify its mechanisms on lipopolysaccharide (LPS)-induced inflammatory responses in mouse macrophages, RAW264.7 cells.

Methods

In the current study, the anti-inflammatory properties of CPT were evaluated using LPS-stimulated RAW264.7 cell model. MTT assay was used to determine the viability of RAW264.7 cells. The anti-inflammatory effects of CPT were measured based on the detection of nitric oxide (NO) production (Griess and flow cytometry assay), and tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) release (ELISA). Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) enzyme expressions were also determined by western blotting. Besides, by using flow cytometry, we also evaluated the effect of CPT on LPS-induced calcium influx. Finally, the underlying anti-inflammatory mechanisms of CPT were investigated using western blotting to assess the protein levels of toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), phosphatidylinositol 3-kinase (PI3K)/AKT, nuclear factor erythroid 2 related factor 2 (Nrf2), mitogen-activated protein kinase (MAPK), and nuclear factor-kappa B (NF-κB) pathways.

Results

Our data showed that CPT inhibited LPS-induced pro-inflammatory cytokine release like IL-6, and TNF-α, as well as NO production. It displayed a significant inhibitory effect on the protein expressions such as iNOS, COX-2, NF-κB pathway like inhibitor of kappa B kinase (IKK)α/β, inhibitor of kappa B (IκB)-α and NF-κB/p65, PI3K/AKT pathway like PI3K and AKT, and MAPK pathway like c-Jun N-terminal kinase (JNK)1/2, extracellular signal-regulated kinase (ERK)1/2, and p38, in LPS-stimulated RAW264.7 macrophages. Moreover, the immunofluorescence results indicated that CPT suppressed NF-κB/p65 translocation from the cytoplasm into the nucleus. Further investigations showed that CPT treatment increased NAD(P)H quinone oxidoreductase-1 (NQO1) and heme oxygenase-1 (HO-1) expressions together with its upstream mediator, Nrf2. In addition, CPT inhibited LPS-induced toll-like receptor 4 (TLR4) and MyD88 expressions in RAW264.7 macrophages.

Conclusions

Collectively, we suggested that CPT exerted significant anti-inflammatory effects via modulating TLR4-MyD88/PI3K/Nrf2 and TLR4-MyD88/NF-κB/MAPK pathways.

Cellular Stress and General Pathological Processes

From the viewpoint of the general pathology, most of the human diseases are associated with a limited number of pathogenic processes such as inflammation, tumor growth, thrombosis, necrosis, fibrosis, atrophy, pathological hypertrophy, dysplasia and metaplasia. The phenomenon of chronic low-grade inflammation could be attributed to non-classical forms of inflammation, which include many neurodegenerative processes, pathological variants of insulin resistance, atherosclerosis, and other manifestations of the endothelial dysfunction. Individual and universal manifestations of cellular stress could be considered as a basic element of all these pathologies, which has both physiological and pathophysiological significance. The review examines the causes, main phenomena, developmental directions and outcomes of cellular stress using a phylogenetically conservative set of genes and their activation pathways, as well as tissue stress and its role in inflammatory and para-inflammatory processes. The main ways towards the realization of cellular stress and its functional blocks were outlined. The main stages of tissue stress and the classification of its typical manifestations, as well as its participation in the development of the classical and non-classical variants of the inflammatory process, were also described. The mechanisms of cellular and tissue stress are structured into the complex systems, which include networks that enable the exchange of information with multidirectional signaling pathways which together make these systems internally contradictory, and the result of their effects is often unpredictable. However, the possible solutions require new theoretical and methodological approaches, one of which includes the transition to integral criteria, which plausibly reflect the holistic image of these processes.

Rutaecarpine inhibits KEAP1-NRF2 interaction to activate NRF2 and ameliorate dextran sulfate sodium-induced colitis

Inflammatory bowel disease (IBD) represents a group of chronic relapsing intestinal disorders. Rutaecarpine (RUT), isolated from the Traditional Chinese Medicine (TCM) of Evodia rutaecarpa, was reported to suppress IBD. However, the mechanism by which RUT ameliorates dextran sulfate sodium (DSS)-induced IBD is largely unknown. By use of nuclear factor-erythroid 2-related factor 2 (NRF2) knockout mice, cell-based studies, surface plasmon resonance (SPR), western blotting analysis, and molecular docking studies, the mechanism by which RUT affects DSS-induced colitis was explored. In DSS-treated wild-type mice but not in Nrf2-null mice, RUT significantly improved colitis as revealed by rescued body weight loss, improved histology and inflammation, and induced expression of NRF2 target genes in colon and ileum. Cell-based studies showed that RUT significantly increased the LD₅₀ for hydrogen peroxide (H₂O₂)-induced cell damage, activated NRF2 nuclear translocation, and suppressed the production of reactive oxygen species in H₂O₂-treated HCT116 cells, activated NRF2 luciferase reporter activities in HCT116 cells and HepG2 cells, and induced expression of NRF2 target genes in primary intestinal epithelial cells. Molecular docking in silico and SPR assays indicated that RUT interacted with kelch-like ECH-associated protein 1 (KEAP1), and extracellular incubation studies revealed that RUT bound to the KEAP1 kelch domain with a calculated equilibrium dissociation constant K_d of 19.6 μM. In conclusion, these results demonstrate that RUT ameliorates DSS-induced colitis, dependent on NRF2, and could be a potential therapeutic option for IBD patients. Mechanistically, RUT potentiates NRF2 nuclear translocation to upregulate NRF2-mediated antioxidant response by directly inhibiting KEAP1-NRF2 interaction.

Fucoxanthinol from the Diatom Nitzschia Laevis Ameliorates Neuroinflammatory Responses in Lipopolysaccharide-Stimulated BV-2 Microglia

In recent years, microalgae have drawn increasing attention as a valuable source of functional food ingredients. Intriguingly, Nitzschia laevis is rich in fucoxanthinol that is seldom found in natural sources. Fucoxanthinol, a marine xanthophyll carotenoid, possesses various beneficial bioactivities. Nevertheless, it's not clear whether fucoxanthinol could exert anti-neuroinflammatory function. In light of these premises, the aim of the present study was to investigate the anti-inflammatory role of fucoxanthinol purified from Nitzschia laevis in Lipopolysaccharide (LPS)-stimulated microglia. The results showed that pre-treatment of fucoxanthinol remarkably attenuated the expression of LPS-induced nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and the production of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), prostaglandin E2 (PGE-2), nitric oxide (NO) and reactive oxygen species (ROS) induction. Modulation mechanism studies revealed that fucoxanthinol hampered nuclear factor-kappa B (NF-κB), Akt, and mitogen-activated protein kinase (MAPK) pathways. Meanwhile, fucoxanthinol led to the enhancement of nuclear translocation of NF-E2-related factor 2 (Nrf2), and the upregulation of heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO-1). Taken together, the results indicated that fucoxanthinol obtained from Nitzschia laevis had great potential as a neuroprotective agent in neuroinflammation and neurodegenerative disorders.

Hydrogen Gas Attenuates Hypoxic-Ischemic Brain Injury via Regulation of the MAPK/HO-1/PGC-1a Pathway in Neonatal Rats

Neonatal hypoxic-ischemic encephalopathy (HIE) is a leading cause of death in neonates with no effective treatments. Recent advancements in hydrogen (H₂) gas offer a promising therapeutic approach for ischemia reperfusion injury; however, the impact of this approach for HIE remains a subject of debate. We assessed the therapeutic effects of H₂ gas on HIE and the underlying molecular mechanisms in a rat model of neonatal hypoxic-ischemic brain injury (HIBI). H₂ inhalation significantly attenuated neuronal injury and effectively improved early neurological outcomes in neonatal HIBI rats as well as learning and memory in adults. This protective effect was associated with initiation time and duration of sustained H₂ inhalation. Furthermore, H₂ inhalation reduced the expression of Bcl-2-associated X protein (BAX) and caspase-3 while promoting the expression of Bcl-2, nuclear factor erythroid-2-related factor 2, and heme oxygenase-1 (HO-1). H₂ activated extracellular signal-regulated kinase and c-Jun N-terminal protein kinase and dephosphorylated p38 mitogen-activated protein kinase (MAPK) in oxygen-glucose deprivation/reperfusion (OGD/R) nerve growth factor-differentiated PC12 cells. Inhibitors of MAPKs blocked H₂-induced HO-1 expression. HO-1 small interfering RNA decreased the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and sirtuin 1 (SIRT1) and reversed the protectivity of H₂ against OGD/R-induced cell death. These findings suggest that H₂ augments cellular antioxidant defense capacity through activation of MAPK signaling pathways, leading to HO-1 expression and subsequent upregulation of PGC-1α and SIRT-1 expression. Thus, upregulation protects NGF-differentiated PC12 cells from OGD/R-induced oxidative cytotoxicity. In conclusion, H₂ inhalation exerted protective effects on neonatal rats with HIBI. Early initiation and prolonged H₂ inhalation had better protective effects on HIBI. These effects of H₂ may be related to antioxidant, antiapoptotic, and anti-inflammatory responses. HO-1 plays an important role in H₂-mediated protection through the MAPK/HO-1/PGC-1α pathway. Our results support further assessment of H₂ as a potential therapeutic for neurological conditions in which oxidative stress and apoptosis are implicated.

Protective Effects of Sulforaphane on Exercise-Induced Organ Damage via Inducing Antioxidant Defense Responses

Regular exercise is beneficial to maintain a healthy lifestyle, but the beneficial effects are lost in the case of acute exhaustive exercise; this causes significant inflammation, oxidative stress along with organ damage. Recently, sulforaphane (SFN), an indirect antioxidant, has drawn special attention for its potential protective effect against inflammation and oxidative stress. However, no studies have been performed regarding acute exhaustive exercise-induced organ damage in association with SFN administration. Therefore, the aim of this study was to investigate the effects of SFN on acute exhaustive exercise-induced organ damage and the mechanisms involved. To perform the study, we divided mice into four groups: Control, SFN, exercise, and SFN plus exercise. The SFN group was administered orally (50 mg/kg body wt) 2 h before the running test. We measured plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH), and acute exhaustive exercise significantly increased these biomarkers. In addition, the mRNA expression of pro-inflammatory cytokines, IL-6, IL-1β, and TNF-α, were significantly increased in the liver of exercise group. However, the SFN plus exercise group showed a significant reduction in the expression of cytokines and blood biomarkers of tissue damage or cell death. Furthermore, we measured mRNA expression of Nrf2, heme oxygenase (HO)-1, and antioxidant defense enzymes expression, i.e., superoxide dismutase (SOD1), catalase (CAT), and glutathione peroxidase (GPx1) in the liver. The expression of all these biomarkers was significantly upregulated in the SFN plus exercise group. Collectively, SFN may protect the liver from exhaustive exercise-induced inflammation via inducing antioxidant defense response through the activation of Nrf2/HO-1 signal transduction pathway.

Protective Effect of Bruguiera gymnorrhiza (L.) Lam. Fruit on Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice: Role of Keap1/Nrf2 Pathway and Gut Microbiota

Bruguiera gymnorrhiza (BG), a medicinal mangrove, and its fruit (a food material) (BGF), have traditionally been used to treat diarrhea (also known as ulcerative colitis) in folk medicine. However, the mechanism of action against colitis remains ambiguous. This study aimed to investigate the potential efficacy and mechanism of BGF on experimental colitis. Colitis was induced by oral intake of dextran sulfate sodium (DSS) and treated with aqueous extract of BGF (25, 50 and 100 mg/kg) for a week. The Disease Activity Index (DAI), colon length, and histological changes of colon were analyzed. The inflammatory and oxidative stress status was explored. The protein expression of Nrf2 and Keap1 in the colon was detected by Western blotting. The mRNA expression of Nrf2 downstream genes (GCLC, GCLM, HO-1 and NQO1) was determined by RT-PCR. Furthermore, the effect on intestinal flora was analyzed. Results indicated that BGF was rich in pinitol, and showed strong antioxidative activity in vitro. Compared with the DSS model, BGF effectively reduced the body weight loss and DAI, restored the colon length, repaired colonic pathological variations, and decreased the histological scores, which was superior to salicylazosulfapyridine (SASP) with smaller dosage. Moreover, BGF not only abated the levels of MDA and inflammatory mediators (TNF-α, IL-6, IL-1β, and IFN-γ), increased the level of IL-10, but also prevented the depletion of SOD and GSH. BGF upregulated the protein level of nuclear Nrf2 and mRNA levels of GCLC, GCLM, HO-1 and NQO1, while significantly inhibited the protein expression of Keap1 and cytosolic Nrf2. Besides, BGF promoted the growth of probiotics (Bifidobacterium, Anaerotruncus, and Lactobacillus) in the gut, and inhibited the colonization of pathogenic bacteria (Bacteroides and Streptococcus), which contributed to the maintenance of intestinal homeostasis. BGF possessed protective effect against DSS-induced colitis. The potential mechanism of BGF may involve the amelioration of inflammatory and oxidative status, activation of Keap1/Nrf2 signaling pathway, and maintenance of micro-ecological balance of the host. This study provides experimental evidence for the traditional application of BGF in the treatment of diarrhea, and indicates that BGF may be a promising candidate against colitis.

Natural products target the hallmarks of chronic diseases

Natural compounds are known to display therapeutic potential against a variety of chronic conditions, including cancer and inflammation. The efficacy of these natural substances can be associated with numerous molecular scaffolds present in extracts of living organisms, both terrestrial and marine. Recently, investigators have identified the ability of natural compounds to trigger immunogenic cell death and subsequent activation of the adaptive immune system. Such findings indicate that the full therapeutic potential of natural products has yet to be defined, and further investigations on such agents will continue to yield novel drug candidates.

Molecular mechanisms in cognitive frailty: potential therapeutic targets for oxygen-ozone treatment

In the last decade, cognitive frailty has gained great attention from the scientific community. It is characterized by high inflammation and oxidant state, endocrine and metabolic alterations, mitochondria dysfunctions and slowdown in regenerative processes and immune system, with a complex and multifactorial aetiology. Although several treatments are available, challenges regarding the efficacy and the costs persist. Here, we proposed an alternative non-pharmacological, non-side-effect, low cost therapy based on anti-inflammation, antioxidant, regenerative and anti-pathogens properties of ozone, through the activation of several molecular mechanisms (Nrf2-ARE, NF-κB, NFAT, AP-1, HIFα). We highlighted how these specific processes could be implicated in cognitive frailty to identify putative therapeutic targets for its treatment. The oxigen-ozone (O₂-O₃) therapy has never been tested for cognitive frailty. This work provides thus wide scientific background to build a consistent rationale for testing for the first time this therapy, that could modulate the immune, inflammatory, oxidant, metabolic, endocrine, microbiota and regenerative processes impaired in cognitive frailty. Although insights are needed, the O₂-O₃ therapy could represent a faster, easier, inexpensive monodomain intervention working in absence of side effects for cognitive frailty.

The Nephroprotective Effect of TNF Receptor-Associated Factor 6 (TRAF6) Blockade on LPS-Induced Acute Renal Injury Through the Inhibition if Inflammation and Oxidative Stress

Background

Inflammation and oxidative stress play important roles in the pathogenesis of acute kidney injury (AKI). TRAF6 functions as a signal transducer in the Toll-like receptor 4 signaling pathway. Several reports have previously implicated TRAF6 signaling in kidney pathology. Here, we investigated whether TRAF6 blockade can mitigate inflammatory responses and oxidative stress in AKI.

Material/Methods

C57BL/6 mice were injected with lipopolysaccharide (LPS, 15 mg/kg) to induce AKI. Double immunofluorescence staining of kidney tissues showed that TRAF6 was localized to renal tubular epithelial cells, and then a tubular epithelial cell line (NRK-52E) was used for in vitro analysis. TRAF6 was blocked in vitro using siRNA and in vivo using AAV2/2 shRNA.

Results

The knockdown of TRAF6 in mice by AAV2-shTRAF6 significantly reduced renal inflammation, oxidative stress, apoptosis and kidney dysfunction in AKI. In vitro, silencing the expression of TRAF6 attenuated LPS(0.5 μg/mL)-induced inflammatory responses and oxidative stress and upregulated proapoptotic factors. Furthermore, the beneficial actions of TRAF6 blockade were closely associated with its ability to increase IκB-α and Nrf2.

Conclusions

Our findings provide direct evidence that TRAF6 mediates LPS-induced inflammation and oxidative stress, leading to renal dysfunction. We also show that TRAF6 inhibition is a potential therapeutic option to prevent AKI.

Cytoprotective effects of berry anthocyanins against induced oxidative stress and inflammation in primary human diabetic aortic endothelial cells

Type 2 diabetes is associated with oxidative stress and low-grade inflammation resulting in endothelial dysfunction (ED). This study determined to explore the protective effects of berry-derived anthocyanins (AC) with potent antioxidant and anti-inflammatory activities in human diabetic endothelial cells upon oxidative and inflammatory stressors. Cultured healthy human aortic endothelial cells (HAEC) and diabetic human aortic endothelial cells (D-HAEC) exposed to oxidative stress by hydrogen peroxide (H₂O₂, 75 μM) and lipopolysaccharide (LPS, 1 μg/mL) as an inflammatory inducer before treatment with AC (50 μl/ml). The results from cytotoxicity assays showed that AC had no significant effects in cell viability (P-value < 0.0001), and exposure to H₂O₂ 75 μM had a less toxic effect (P-value < 0.05). Although, AC significantly decreased H₂O₂-induced cytotoxicity and oxidative stress in both HAEC and D-HAEC cell lines (P-value < 0.0001), no positive impact of AC was found on the GSSG/GSH ratios (P-value < 0.05). Exposure to the LPS increased the production of IL-6 in both HAEC and D-HAEC cell lines (P-value < 0.0001), whereas AC treatment reduced LPS-induced IL-6 production in both cell lines with a more robust impact on D-HAEC (P-value < 0.0001). While LPS increased inflammasome assembling and caspase-1 activation, AC treatment inhibited caspase-1 activation in D-HAEC (P ≤ 0.05). This study indicated that berry anthocyanins reduced oxidative stress and inflammation via the inhibition of the NF-ƙB signaling pathway, which contributes to mitigating the diabetes-induced up-regulation of NF-ƙB.

FSGHF3 and peptides, prepared from fish skin gelatin, exert a protective effect on DSS-induced colitis via the Nrf2 pathway

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic inflammatory disease affecting the colon, and its incidence is rising worldwide.

Inflammation and Oxidative Stress in Chronic Kidney Disease-Potential Therapeutic Role of Minerals, Vitamins and Plant-Derived Metabolites

Chronic kidney disease (CKD) is a debilitating pathology with various causal factors, culminating in end stage renal disease (ESRD) requiring dialysis or kidney transplantation. The progression of CKD is closely associated with systemic inflammation and oxidative stress, which are responsible for the manifestation of numerous complications such as malnutrition, atherosclerosis, coronary artery calcification, heart failure, anemia and mineral and bone disorders, as well as enhanced cardiovascular mortality. In addition to conventional therapy with anti-inflammatory and antioxidative agents, growing evidence has indicated that certain minerals, vitamins and plant-derived metabolites exhibit beneficial effects in these disturbances. In the current work, we review the anti-inflammatory and antioxidant properties of various agents which could be of potential benefit in CKD/ESRD. However, the related studies were limited due to small sample sizes and short-term follow-up in many trials. Therefore, studies of several anti-inflammatory and antioxidant agents with long-term follow-ups are necessary.

The Protective Role of Tanshinone IIA in Silicosis Rat Model via TGF-β1/Smad Signaling Suppression, NOX4 Inhibition and Nrf2/ARE Signaling Activation

Purpose

Silicosis is an occupational disease caused by inhalation of silica and there are no effective drugs to treat this disease. Tanshinone IIA (Tan IIA), a traditional natural component, has been reported to possess anti-inflammatory, antioxidant, and anti-fibrotic properties. The current study’s purpose was to examine Tan IIA’s protective effects against silica-induced pulmonary fibrosis and to explore the underlying mechanisms.

Methods

48 male SD rats were randomly divided into four groups (n=12): i) Control group; ii) Silicosis group; iii) Tan IIA group; iv) Silicosis +Tan IIA group. Two days after modeling, the rats of Tan IIA group and Silicosis +Tan IIA group were given intraperitoneal administration 25 mg/kg/d Tan IIA for 40 days. Then, the four groups of rats were sacrificed and the lung inflammatory responses were measured by ELISA, lung damage and fibrosis were analyzed by hematoxylin and eosin (H&E) staining and Masson staining, the expression levels of collagen I, fibronectin and α-smooth muscle actin (α-SMA) were measured by immunohistochemistry. The markers of oxidative stress were measured by commercial kits, and the activity of the TGF-β1/Smad and NOX4, Nrf2/ARE signaling pathways were measured by RT-PCR and Western blotting.

Results

The silica-induced pulmonary inflammtory responses, structural damage and fibrosis were significantly attenuated by Tan IIA treatment. In addition, treatment with Tan IIA decreased collagen I, fibronectin and α-SMA expression, and inhibited TGF-β1/Smad signaling in the lung tissue. The upregulated levels of oxidative stress markers in silicosis rats were also markedly restored following Tan IIA treatment. Furthermore, treatment with Tan IIA reduced NOX4 expression and enhanced activation of the Nrf2/ARE pathway in the lung tissue of silicosis rats.

Conclusion

These findings suggest that Tan IIA may protect lung from silica damage via the suppression of TGF-β1/Smad signaling, inhibition of NOX4 expression and activation of the Nrf2/ARE pathway.

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Role of Nrf2 in inflammatory response in lung of mice exposed to zinc oxide nanoparticles

Background

Zinc oxide nanoparticles (ZnO-NPs) are widely used in many industrial sectors and previous studies have reported that exposure of the lungs to ZnO-NPs induces both acute and/or chronic pulmonary inflammation, but the exact mechanism underlying such response remains elusive. This study investigated the role of nuclear factor-erythroid 2-related factor (Nrf2) in pulmonary inflammation induced by exposure to ZnO-NPs using Nrf2 null (Nrf2^−/−) mice.

Methods

Twenty-four male Nrf2^−/− mice and thirty male wild type C57BL/6 J mice were divided into three groups of eight and ten each respectively, and exposed once to ZnO-NPs at 0, 10, 30 μg/mouse by pharyngeal aspiration. At 14 days after the exposure to ZnO-NPs, bronchoalveolar lavage fluid (BALF) and lungs were collected to quantify protein level and the number of inflammatory cells. The mRNA levels of Nrf2-dependent antioxidant enzymes and inflammatory cytokines in lung tissue were measured.

Results

Exposure to ZnO-NPs dose-dependently increased the number of total cells, macrophages, lymphocytes and eosinophils in BALF both in Nrf2^−/− mice and wild type mice, but the magnitude of increase was significantly higher in Nrf2^−/− mice than wild type mice. The number of neutrophils in BALF increased in Nrf2^−/− mice, being accompanied by marginal trend of increase in mRNA expression of MIP-2, neutrophil chemoattractant, but such changes were not observed in wild type mice. Exposure to ZnO-NPs did not dose-dependently increase mRNA level of Nrf2-dependent antioxidant enzymes both in Nrf2^−/− mice and wild type mice.

Conclusion

Pharyngeal aspiration of ZnO-NPs induced infiltration of inflammatory cells in the lung of mice, but minimally induced Nrf2-dependent antioxidant enzymes. The results suggest that Nrf2 play a role in negative regulation on ZnO-NP exposure-induced neutrophil migration, but does not demonstrate that the regulation is through suppression of oxidative stress.

Increased oxidative stress, inflammation, and glutamate: Potential preventive and therapeutic targets for hearing disorders

Hearing disorders constitute one of the major health concerns in the USA. Decades of basic and clinical studies have identified numerous ototoxic agents and investigated their modes of action on the inner ear, utilizing tissue culture as well as animal and human models. Current preventive and therapeutic approaches are considered unsatisfactory. Therefore, additional modalities should be developed. Many studies suggest that increased levels of oxidative stress, chronic inflammation, and glutamate play an important role in the initiation and progression of damage to the inner ear leading to hearing impairments. To prevent these cellular deficits, antioxidants, anti-inflammatory agents, and antagonists of glutamate receptor have been used individually or in combination with limited success. It is essential, therefore, to simultaneously enhance the levels of antioxidant enzymes by activating the Nrf2 (a nuclear transcriptional factor) pathway, dietary and endogenous antioxidant compounds, and B12-vitamins in order to reduce the levels of oxidative stress, chronic inflammation, and glutamate at the same time. This review presents evidence to show that increased levels of these cellular metabolites, biochemical or factors are involved in the pathogenesis of cochlea leading to hearing impairments. It presents scientific rationale for the use of a mixture of micronutrients that may decrease the levels of oxidative damage, chronic inflammation, and glutamate at the same time. The benefits for using oral administration of proposed micronutrient mixture in humans are presented. Animal and limited human studies indirectly suggest that orally administered micronutrients can accumulate in the inner ear. Therefore, this route of administration may be useful in prevention, and in combination with standard care, in improved management of hearing problems following exposure to well-recognized and studied ototoxic agents, such as noise, cisplatin, aminoglycoside antibiotics, and advanced age.

Chitosan Oligosaccharide Attenuates Nonalcoholic Fatty Liver Disease Induced by High Fat Diet through Reducing Lipid Accumulation, Inflammation and Oxidative Stress in C57BL/6 Mice

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease closely associated with metabolic syndrome, but there are no validated pharmacological therapies. The aim of this study was to investigate the effect of chitosan oligosaccharide (COS) on NAFLD. Mice were fed either a control diet or a high-fat diet (HFD) with or without COS (200 or 400 mg/kg body weight (BW)) by oral gavage for seven weeks. Administration with COS significantly lowered serum lipid levels in the HFD-fed mice. The hepatic lipid accumulation was significantly decreased by COS, which was attributed to decreased expressions of lipogenic genes and increased expressions of fatty β-oxidation-related genes. Moreover, pro-inflammatory cytokines, neutrophils infiltration, and macrophage polarization were decreased by COS in the liver. Furthermore, COS ameliorated hepatic oxidative stress by activating the nuclear factor E2-related factor 2 (Nrf2) pathway and upregulating gene expressions of antioxidant enzymes. These beneficial effects were mediated by the activation of the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Therefore, COS might be a potent dietary supplement to ameliorate NAFLD.