Shizukaol C alleviates trimethylamine oxide-induced inflammation through activating Keap1-Nrf2-GSTpi pathway in vascular smooth muscle cell.

BACKGROUND: Cardiovascular disease is one of the main causes of global mortality, and there is an urgent need for effective treatment strategies. Gut microbiota-dependent metabolite trimethylamine-N-oxide (TMAO) promotes the development of cardiovascular diseases, and shizukaol C, a natural sesquiterpene isolated from Chloranthus multistachys with various biological activities, might exhibit beneficial role in preventing TMAO-induced vascular inflammation. PURPOSE: The purpose of this study was to investigate the anti-inflammatory effects and the underlying mechanisms of shizukaol C on TMAO-induced vascular inflammation. METHODS: The effect and underlying mechanism of shizukaol C on TMAO-induced adhesion molecules expression, bone marrow-derived macrophages (BMDM) adhesion to VSMC were evaluated by western blot, cell adhesion assay, co-immunoprecipitation, immunofluorescence assay, and quantitative Real-Time PCR, respectively. To verify the role of shizukaol C in vivo, TMAO-induced vascular inflammation model were established using guidewire-induced injury on mice carotid artery. Changes in the intima area and the expression of GSTpi, VCAM-1, CD68 were examined using haematoxylin-eosin staining, and immunofluorescence assay. RESULTS: Our data demonstrated that shizukaol C significantly suppressed TMAO-induced adhesion molecule expression and the bone marrow-derived macrophages (BMDM) adhesion in vascular smooth muscle cells (VSMC). Mechanically, shizukaol C inhibited TMAO-induced c-Jun N-terminal kinase (JNK)-nuclear factor-kappa B (NF-κB)/p65 activation, and the JNK inhibition was dependent on the shizukaol C-mediated glutathione-S-transferase pi (GSTpi) expression. By further molecular docking and protein-binding analysis, we demonstrated that shizukaol C directly binds to Keap1 to induce Nrf2 nuclear translocation and upregulated GSTpi expression. Consistently, our in vivo experiment showed that shizukaol C elevated the expression level of GSTpi in carotid arteries and alleviates TMAO-induced vascular inflammation. CONCLUSION: Shizukaol C exerts anti-inflammatory effects in TMAO-treated VSMC by targeting Keap1 and activating Nrf2-GSTpi signaling and resultantly inhibits the downstream JNK-NF-κB/p65 activation and VSMC adhesion, and alleviates TMAO-induced vascular inflammation in vivo, suggesting that shizukaol C may be a potential drug for treating TMAO-induced vascular diseases.

Mitigative potential of kaempferide against polyethylene microplastics induced testicular damage by activating Nrf-2/Keap-1 pathway.

Polyethylene microplastics (PE-MPs) are one of the environmental contaminants that instigate oxidative stress (OS) in various organs of the body, including testes. Kaempferide (KFD) is a plant-derived natural flavonol with potential neuroprotective, hepatoprotective, anti-cancer, anti-oxidant and anti-inflammatory properties. Therefore, the present study was designed to evaluate the alleviative effects of KFD against PE-MPs-prompted testicular toxicity in rats. Fourty eight adult male albino rats were randomly distributed into 4 groups: control, PE-MPs-administered (1.5 mgkg-1), PE-MPs (1.5 mgkg-1) + KFD (20 mgkg-1) co-treated and KFD (20 mgkg-1) only treated group. PE-MPs intoxication significantly (P < 0.05) lowered the expression of Nrf-2 and anti-oxidant enzymes, while increasing the expression of Keap-1. The activities of anti-oxidants i.e., catalase (CAT), glutathione reductase (GSR), superoxide dismutase (SOD), hemeoxygene-1 (HO-1) and glutathione peroxidase (GPx) were reduced, besides malondialdehyde (MDA) and reactive oxygen species (ROS) contents were increased significantly (P < 0.05) following the PE-MPs exposure. Moreover, PE-MPs exposure significantly (P < 0.05) reduced the sperm motility, viability and count, whereas considerably (P < 0.05) increased the dead sperm number and sperm structural anomalies. Furthermore, PE-MPs remarkably (P < 0.05) decreased steroidogenic enzymes and Bcl-2 expression, while increasing the expression of Caspase-3 and Bax. PE-MPs exposure significantly (P < 0.05) reduced the levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone, whereas inflammatory indices were increased. PE-MPs exposure also induced significant histopathological damages in the testes. Nevertheless, KFD supplementation significantly (P < 0.05) abrogated all the damages induced by PE-MPs. The findings of our study demonstrated that KFD could significantly attenuate PE-MPs-instigated OS and testicular toxicity, due to its anti-oxidant, anti-inflammatory, androgenic and anti-apoptotic potential.

Sulforaphane improves cognitive dysfunction after surgery and anesthesia in mice: The role of Keap1-Nrf2 signaling.

Anesthesia and surgery are likely causing cognitive dysfunction in patients, especially the elderly. However, the underlying pathogenic mechanisms largely remain unclear. Accumulating evidence suggest that signaling between Kelch-like erythroid cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) plays an important role in the pathogenesis and treatment of brain dysfunction, while sulforaphane (SFN), a natural compound acting as an Nrf2 agonist, can improve brain function. In the present study, we used 9-month-old mice to perform tibial fracture surgery under isoflurane general anesthesia. Hierarchical cluster analysis of Morris water maze test (MWMT) analysis was performed to classify mice into post-operative cognitive dysfunction (POCD) versus non-POCD phenotypes. Expression levels of Keap1 and Nrf2 were significantly decreased in the medial prefrontal cortex (mPFC), hippocampus and liver, but not in the nucleus accumbens, muscle and gut of POCD mice compared to control and non-POCD mice. Interestingly, both pretreatment and posttreatment with SFN significantly improved the abnormal behaviors of mice in the MWMT, in parallel with the up-regulated levels of Keap1-Nrf2 signaling in the mPFC, hippocampus and liver. In conclusion, these results suggest that decreased Keap1-Nrf2 signaling in the mPFC, hippocampus and liver may contribute to the onset of POCD, and that SFN exerts facilitating effects on POCD symptoms by increasing Keap1-Nrf2 signaling.

Pachymic Acid Ameliorates Pulmonary Hypertension by Regulating Nrf2-Keap1-ARE Pathway.

OBJECTIVE: Pulmonary hypertension (PH) is a severe pulmonary vascular disease that eventually leads to right ventricular failure and death. The purpose of this study was to investigate the mechanism by which pachymic acid (PA) pretreatment affects PH and pulmonary vascular remodeling in rats. METHODS: PH was induced via hypoxia exposure and administration of PA (5 mg/kg per day) in male Sprague-Dawley rats. Hemodynamic parameters were measured using a right ventricular floating catheter and pulmonary vascular morphometry was measured by hematoxylin-eosin (HE), α-SMA and Masson staining. MTT assays and EdU staining were used to detect cell proliferation, and apoptosis was analyzed by TUNEL staining. Western blotting and immunohistochemistry were used to detect the expression of proteins related to the Nrf2-Keap1-ARE pathway. RESULTS: PA significantly alleviated hypoxic PH and reversed right ventricular hypertrophy and pulmonary vascular remodeling. In addition, PA effectively inhibited proliferation and promoted apoptosis in hypoxia-induced pulmonary artery smooth muscle cells (PASMCs). Moreover, PA pretreatment inhibited the expression of peroxy-related factor (MDA) and promoted the expression of antioxidant-related factors (GSH-PX and SOD). Furthermore, hypoxia inhibited the Nrf2-Keap1-ARE signaling pathway, while PA effectively activated this pathway. Most importantly, addition of the Nrf2 inhibitor ML385 reversed the inhibitory effects of PA on ROS generation, proliferation, and apoptosis tolerance in hypoxia-induced PASMCs. CONCLUSION: Our study suggests that PA may reverse PH by regulating the Nrf2-Keap1-ARE signaling pathway.

Dietary arsenic supplementation induces oxidative stress by suppressing nuclear factor erythroid 2-related factor 2 in the livers and kidneys of laying hens.

This study investigated the effects of dietary arsenic supplementation on laying performance, egg quality, hepatic and renal histopathology, and oxidative stress in the livers and kidneys of laying hens. Furthermore, the nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway was explored to reveal the molecular mechanism of the stress. Five hundred and twelve 40-week-old Hyline White laying hens were randomly allocated to 4 groups with 8 pens per group and 16 hens per pen. The doses of arsenic administered to the 4 groups were 0.95, 20.78, 40.67, and 60.25 mg/kg. The results revealed that dietary arsenic supplementation significantly reduced hen-day egg production (P < 0.05), average egg weight (P < 0.05), Haugh units (P < 0.05), albumen height (P < 0.05), and eggshell strength (P < 0.05). Dietary arsenic supplementation also induced the accumulation of arsenic and histopathological damages in the liver and kidney. In accordance, dietary arsenic supplementation significantly enhanced serum alanine aminotransferase (P < 0.05), aspartate aminotransferase (P < 0.05), blood urea nitrogen (P < 0.05), and uric acid (P < 0.05) levels. After arsenic exposure, the activities of superoxide dismutase (SOD) (P < 0.05), catalase (P < 0.01), glutathione reductase (P < 0.05), and glutathione peroxidase (P < 0.05), and glutathione content (P < 0.05) were significantly decreased, while the malondialdehyde level was significantly increased (P < 0.05) in the liver and kidney. Positive correlations occurred between antioxidant enzyme activities and antioxidant enzyme gene expressions in the liver and kidney, except for renal manganese superoxide dismutase gene expression and SOD activity. Additionally, hepatic and renal Nrf2 mRNA expression was positively correlated with antioxidant gene expressions and negatively correlated with Keap1 mRNA expression. In summary, dietary arsenic supplementation induced oxidative stress by suppressing the Nrf2-Keap1 pathway in the livers and kidneys of laying hens.

The effect of diclofenac sodium intoxication on the cardiovascular system in rats.

OBJECTIVES: Diclofenac sodium (DS) is a widely used nonsteroidal anti-inflammatory drug. Although its high doses are known to cause toxic effects in many tissues including liver and kidney, the effects on the cardiovascular system (CVS) have not been fully elucidated yet. Therefore, this study aimed to investigate the effect of DS on CVS. METHODS: The Control group did not receive medication; however, a single dose of 240 mg/kg DS was administered orally to the DS group. Electrocardiography (ECG) measurements were performed in all animals before (0thhour) and after (1st,6th,12th,24thhour) intoxication. After 24 h, All animals were sacrificed. Biochemical (malondialdehyde [MDA], and glutathione (GSH), Apelin, Elabela, Meteorin, Endoglin, Keap1, and Nrf2) and histopathological analyzes were performed on heart tissue samples. RESULTS: ECG results showed that there was a statistically significant increase in QTc, QRS, and heart rate at the 12th and 24th hours in the DS group. The biochemical analysis showed that GSH, Apelin, Keap1, and NRF2 values decreased significantly while Meteorin and Endoglin levels increased in the DS group. When histopathological results were evaluated, distinct lesions were observed in the DS group. CONCLUSION: In conclusion, high doses of DS intake can cause adverse effects on and damage to CVS.

A novel pyrazolo [3,4-d] pyrimidine, KKC080106, activates the Nrf2 pathway and protects nigral dopaminergic neurons.

The transcription factor nuclear factor-erythroid 2-related factor-2 (Nrf2) is known to induce neuroprotective and anti-inflammatory effects and is considered to be an excellent molecular target for drugs related to neurodegenerative disease therapy. Nrf2 activators previously tested in clinical trials were electrophilic, causing adverse effects due to non-selective and covalent modification of cellular thiols. In order to circumvent this issue, we constructed and screened a chemical library consisting of 241 pyrazolo [3,4-d] pyrimidine derivatives and discovered a novel, non-electrophilic compound: 1-benzyl-6-(methylthio)-N-(1-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidine-4-amine (KKC080106). KKC080106 was able to activate Nrf2 signaling as it increases the cellular levels of Nrf2, binds to the Nrf2 inhibitor protein Keap1, and causes the accumulation of nuclear Nrf2. We also observed an increase in the expression levels of Nrf2-dependent genes for antioxidative/neuroprotective enzymes in dopaminergic neuronal cells. In addition, in lipopolysaccharide-activated microglia, KKC080106 suppressed the generation of the proinflammatory markers, such as IL-1ß, TNF-α, cyclooxygenase-2, inducible nitric oxide synthase, and nitric oxide, and inhibited the phosphorylation of kinases known to be involved in inflammatory signaling, such as IκB kinase, p38, JNK, and ERK. As a drug, KKC080106 exhibited excellent stability against plasma enzymes and a good safety profile, evidenced by no mortality after the administration of 2000 mg/kg body weight, and minimal inhibition of the hERG channel activity. Pharmacokinetic analysis revealed that KKC080106 has good bioavailability and enters the brain after oral and intravenous administration, in both rats and mice. In MPTP-treated mice that received KKC080106 orally, the compound blocked microglial activation, protected the nigral dopaminergic neurons from degeneration, and prevented development of the dopamine deficiency-related motor deficits. These results suggest that KKC080106 has therapeutic potential for neurodegenerative disorders such as Parkinson's disease.

Targeting Keap1/Nrf2/ARE signaling pathway in multiple sclerosis.

Multiple sclerosis (MS) is a neurologic autoimmune disorder featured by chronic inflammation of the central nervous system, demyelination and axonal damage. Recently, the term "oxinflammation" has been proposed to depict the vicious circle of chronic inflammation and oxidative stress (OS). OS promotes demyelination and neurodegeneration directly, by oxidation of lipids, proteins, and DNA but also indirectly, by inducing a dysregulation of the immunity and favoring the state of pro-inflammatory response. Many of the actors of this delicately tuned network are controlled by Keap1/Nrf2/ARE signaling pathway, a principal regulator of antioxidant and phase II detoxification genes. This pathway also has a pivotal role in inflammation, and therefore possesses a great potential in the treatment of MS. The aim of this review is to provide the newest insights in the preclinical and clinical evidence of Nrf2 induction in the regeneration of the antioxidant response and attenuation of inflammation in MS. Preclinical studies have indicated that activators of this pathway, such as epigallocatechin gallate (EGCG), curcumin, melatonin, resveratrol, and sulforaphane might be a promising therapeutic option in amelioration of MS symptoms, nevertheless, the efficacy and safety of these compounds have to be confirmed in future clinical trials.

SQSTM1/p62 activates NFE2L2/NRF2 via ULK1-mediated autophagic KEAP1 degradation and protects mouse liver from lipotoxicity.

Lipotoxicity, induced by saturated fatty acid (SFA)-mediated cell death, plays an important role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). The KEAP1 (kelch like ECH associated protein 1)-NFE2L2/NRF2 (nuclear factor, erythroid 2 like 2) pathway is a pivotal defense mechanism against lipotoxicity. We previously reported that SQSTM1/p62 has a cytoprotective role against lipotoxicity through activation of the noncanonical KEAP1- NFE2L2 pathway in hepatocytes. However, the underlying mechanisms and physiological relevance of this pathway have not been clearly defined. Here, we demonstrate that NFE2L2-mediated induction of SQSTM1 activates the noncanonical KEAP1-NFE2L2 pathway under lipotoxic conditions. Furthermore, we identified that SQSTM1 induces ULK1 (unc-51 like autophagy activating kinase 1) phosphorylation by facilitating the interaction between AMPK (AMP-activated protein kinase) and ULK1, leading to macroautophagy/autophagy induction, followed by KEAP1 degradation and NFE2L2 activation. Accordingly, the activity of this SQSTM1-mediated noncanonical KEAP1-NFE2L2 pathway conferred hepatoprotection against lipotoxicity in the livers of conventional sqstm1- and liver-specific sqstm1-knockout mice. Moreover, this pathway activity was evident in the livers of patients with nonalcoholic fatty liver. This axis could thus represent a novel target for NAFLD treatment. Abbreviations: ACACA: acetyl-CoA carboxylase alpha; ACTB: actin beta; BafA1: bafilomycin A1; CM-H2DCFDA:5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate; CQ: chloroquine; CUL3: cullin 3; DMSO: dimethyl sulfoxide; FASN: fatty acid synthase; GSTA1: glutathione S-transferase A1; HA: hemagglutinin; Hepa1c1c7: mouse hepatoma cells; HMOX1/HO-1: heme oxygenase 1; KEAP1: kelch like ECH associated protein 1; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; MTORC1: mechanistic target of rapamycin kinase complex 1; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NAC: N-acetyl-L-cysteine; NAFLD: nonalcoholic fatty liver disease; NASH: nonalcoholic steatohepatitis; NFE2L2/NRF2: nuclear factor, erythroid 2 like 2; NQO1: NAD(P)H quinone dehydrogenase 1; PA: palmitic acid; PARP: poly (ADP-ribose) polymerase 1; PRKAA1/2: protein kinase AMP-activated catalytic subunits alpha1/2; RBX1: ring-box 1; ROS: reactive oxygen species; SESN2: sestrin 2; SFA: saturated fatty acid; siRNA: small interfering RNA; SQSTM1/p62: sequestosome 1; SREBF1: sterol regulatory element binding transcription factor 1; TBK1: TANK binding kinase 1; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling; ULK1: unc-51 like autophagy activating kinase.

microRNA-592 blockade inhibits oxidative stress injury in Alzheimer's disease astrocytes via the KIAA0319-mediated Keap1/Nrf2/ARE signaling pathway.

MicroRNA-592 (miR-592) has been reported to play a significant role in mediating neuronal activity, but its possible link with Alzheimer's disease (AD) remains unclear. We aimed to explore the mechanism of miR-592 in oxidative stress (OS) injury of astrocytes (ASTs) from AD rat models induced by D-galactose or Aß25-35 injection. Bioinformatics website and dual-luciferase reporter gene assay clarified the binding affinity between miR-592 and KIAA0319. KIAA0319 was identified as a target gene of miR-592. The mechanism of miR-592, KIAA0319 and the Keap1/Nrf2/ARE signaling pathway in AD was examined after transducing miR-592 mimic, miR-592 inhibitor and siRNA-KIAA0319 into ASTs to query cell viability, OS injury and reactive oxygen species (ROS). The rat models of AD Exhibited highly expressed miR-592 and poorly expressed KIAA0319. Furthermore, inhibition of miR-592 diminished C-Keap1 expression and enhanced N-Nrf2 and NQO1 expression, thus promoting cell viability and reducing OS injury of ASTs. Taken together, these findings suggested that the downregulation of miR-592 inhibited OS injury of ASTs in rat models of AD by up-regulating KIAA0319 through the activation of the Keap1/Nrf2/ARE signaling pathway.

Involvement of the Nrf2-Keap1 signaling pathway in protection against thallium-induced oxidative stress and mitochondrial dysfunction in primary hippocampal neurons.

Thallium ion (Tl+) and its neurotoxic products are widely known to cause severe neurological complications. However, the exact mechanism of action remains unknown, with limited therapeutic options available. This study aims to examine the toxic effects of Thallium (I) Nitrate (TlNO3) on primary hippocampal neurons of E17-E18 Wistar rat embryos, and the potential neuroprotective role of Nrf2- Keap1 signaling pathway against thallium-induced oxidative stress and mitochondrial dysfunction. TlNO3 induces a significant increase in reactive oxygen species levels and mitochondrial dysfunction in primary hippocampal neurons. Furthermore, the Nrf2-Keap1 signaling pathway played a protective role against TlNO3-induced hippocampal neuronal cytotoxicity. Moreover, mitochondrial fusion protein Mitofusin 2 (Mfn2) levels significantly decreased in hippocampal neurons when exposed to TlNO3, indicating that Mfn2 protein levels are linked to TlNO3-induced neurotoxicity. t-BHQ, a Nrf2 and phase II detoxification enzyme inducer, counteracted the oxidative damage in hippocampal neurons by activating the Nrf2-Keap1 signaling pathway after TlNO3 exposure; the activated Nrf2-Keap1 pathway could then maintain Mfn2 function by regulating Mfn2 protein expression. Thus, Nrf2-Keap1 pathway activation plays a protective role in Tl+-induced brain damage, and specific agonists have been identified to have great potential for treating thallium poisoning.

Selenepezil, a Selenium-Containing Compound, Exerts Neuroprotective Effect via Modulation of the Keap1-Nrf2-ARE Pathway and Attenuates Aß-Induced Cognitive Impairment in Vivo.

Oxidative stress is a major risk factor for neurodegenerative disease. The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2 related factor 2 (Nrf2)-antioxidant response element (ARE) pathway is one of the most potent defensive systems against oxidative stress. Selenepezil, a selenium-based compound, was previously found to exhibit excellent acetylcholinesterase (AChE) inhibition, to mimic endogenous glutathione peroxidase (GPx) activity, and to exhibit scavenging activity for hydrogen peroxide in vitro. However, none of these activities have been evaluated in a cellular model, and detailed molecular mechanisms are not elucidated. Moreover, whether selenepezil ameliorates memory deficits in vivo remains unknown. This study validated the cytoprotective effect of selenepezil against 6-hydroxydopamine (6-OHDA)- or H2O2-induced SH-SY5Y cell damage via alleviation or neutralization of intracellular microtubule disorder, reactive oxygen species (ROS) accumulation, mitochondrial dysfunction, and cell apoptosis. Our study clearly demonstrated that selenepezil pretreatment exhibited remarkable cytoprotective effect in a Nrf2-dependent manner via activating the Keap1-Nrf2-ARE pathway and stimulating the transcription of Nrf2-ARE-regulated cytoprotective genes. Moreover, selenepezil·HCl exerts neuroprotective effect via attenuating Aß-induced cognitive impairment in Alzheimer's disease (AD) rat and was more active than the reference drug donepezil. In summary, selenepezil deserves further consideration for AD therapy.

Sulforaphane - role in aging and neurodegeneration.

In the last several years, numerous molecules derived from plants and vegetables have been tested for their antioxidant, anti-inflammatory, and anti-aging properties. One of them is sulforaphane (SFN), an isothiocyanate present in cruciferous vegetables. SFN activates the antioxidant and anti-inflammatory responses by inducing Nrf2 pathway and inhibiting NF-κB. It also has an epigenetic effect by inhibiting HDAC and DNA methyltransferases and modifies mitochondrial dynamics. Moreover, SFN preserves proteome homeostasis (proteostasis) by activating the proteasome, which has been shown to lead to increased cellular lifespan and prevent neurodegeneration. In this review, we describe some of the molecular and physical characteristics of SFN, its mechanisms of action, and the effects that SFN treatment induces in order to discuss its relevance as a "miraculous" drug to prevent aging and neurodegeneration.

Therapeutic targeting of the NRF2 and KEAP1 partnership in chronic diseases.

The transcription factor NF-E2 p45-related factor 2 (NRF2; encoded by NFE2L2) and its principal negative regulator, the E3 ligase adaptor Kelch-like ECH-associated protein 1 (KEAP1), are critical in the maintenance of redox, metabolic and protein homeostasis, as well as the regulation of inflammation. Thus, NRF2 activation provides cytoprotection against numerous pathologies including chronic diseases of the lung and liver; autoimmune, neurodegenerative and metabolic disorders; and cancer initiation. One NRF2 activator has received clinical approval and several electrophilic modifiers of the cysteine-based sensor KEAP1 and inhibitors of its interaction with NRF2 are now in clinical development. However, challenges regarding target specificity, pharmacodynamic properties, efficacy and safety remain.

Activation of Keap1-Nrf2 signaling by 4-octyl itaconate protects human umbilical vein endothelial cells from high glucose.

High glucose (HG) induces oxidative injury to cultured human umbilical vein endothelial cells (HUVECs). Recent studies have discovered 4-octyl itaconate (OI) as a novel and cell permeable Nrf2 (nuclear-factor-E2-related factor 2) activator. Its potential activity in HG-treated HUVECs was tested here. In HUVECs OI disrupted Keap1-Nrf2 association, causing Nrf2 protein accumulation and nuclear translocation, as well as transcription and expression of Nrf2-ARE-dependent genes, including HO1, NQO1 and GCLM. Significantly, pretreatment with OI potently inhibited HG (40 mM glucose)-induced death and apoptosis of HUVECs. Moreover, OI potently inhibited HG-induced reactive oxygen species (ROS) production, lipid peroxidation, superoxide accumulation and mitochondrial depolarization in HUVECs. Activation of Nrf2 is required for OI-induced cytoprotection in HUVECs. Nrf2 shRNA or knockout (by CRISPR/Cas9 method) reversed OI-mediated HUVEC protection against HG. Further studies showed that Keap1 silencing or Cys151S mutation mimicked and nullified OI-induced activity in HUVECs. Taken together, we conclude that OI activates Keap1-Nrf2 signaling to protect HUVECs from HG.

Protective Effects of Astragaloside IV Combined with Budesonide in Bronchitis in Rats by Regulation of Nrf2/Keap1 Pathway.

BACKGROUND This study was conducted to evaluate the effects of astragaloside IV and budesonide on bronchitis in rats and to explore the mechanism involved. MATERIAL AND METHODS Eighty Sprague-Dawley (SD) rats were randomly divided into 5 groups, including a Bronchitis model group (BM), a Budesonide group (BG), an Astragaloside IV group (AG), an Astragaloside IV combined with Budesonide group (CG), and a blank control group (BC). Lung tissue was stained with hematoxylin and eosin (H&E). The activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were detected by enzyme-linked immunosorbent assay (ELISA). The nuclear factor erythroid 2 [NF-E2]-related factor 2 (Nrf2), Kelch-like erythroid cell-derived protein with CNC homology [ECH]-associated protein 1 (Keap1), BTB and CNC homology 1 (Bach1), B-cell lymphoma-2(Bcl-2), and BCl-2-associated X protein (Bax) mRNA and protein were examined by RT-PCR and Western blot, respectively. RESULTS Compared with the Bronchitis model group, the lung tissue lesions in the Budesonide group, Astragaloside IV group, and Astragaloside IV combined with Budesonide group were effectively ameliorated and the airway resistance was significantly decreased. The activities of SOD, GSH-Px, and CAT were increased after treatment with drugs, while the content of MDA was decreased. The levels of Nrf2, Keap1, and Bcl-2 proteins were increased and the levels of Bach1 and Bax were decreased after treatment with Budesonide and Astragaloside IV. CONCLUSIONS Astragaloside IV combined with budesonide can ameliorate the lesions caused by bronchitis in rats through activating the Nrf2/Keap1 pathway, which plays a protective role on anti-oxidative stress injury.

Diphenyl diselenide regulates Nrf2/Keap-1 signaling pathway and counteracts hepatic oxidative stress induced by bisphenol A in male mice.

Bisphenol A (BPA) is a chemical toxicant that has deleterious effects on human. BPA causes oxidative stress in tissues, including the liver. Diphenyl diselenide (PhSe)2 improves the antioxidant response via activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/Kelch-like ECH-associated protein (keap 1) pathway in macrophage cells. In the present study, we investigated whether (PhSe)2 counteracts hepatic oxidative stress induced by BPA in male and female Swiss mice. Three-week-old mice received by the intragastric (i.g.) route BPA (5 mg/kg) from 21st to 60th postnatal day (PND). At PND 61, the mice were treated with (PhSe)2 (1 mg/kg, i.g.) for seven days. Parameters of hepatic damage and oxidative stress were determined in male and female mice. The results show that BPA increased the activity of aspartate aminotransferase in female mice, and in male mice the activity of alanine aminotranseferase was increased. Male and female mice had an increase in fat mass accumulation. Male mice showed an increase in hepatic oxidative damage of proteins and a decrease in non-enzymatic (ascorbic acid and non-protein thiol) and enzymatic (superoxide dismutase) defenses, which are consistent with oxidative stress status. Male mice were more susceptible than female mice to hepatic oxidative stress induced by BPA. BPA decreased Nrf2/Keap1 protein content in male mice. (PhSe)2 reduced hepatic oxidative stress induced by BPA in male mice. Our results demonstrate that male mice were more susceptible to hepatic oxidative stress induced by BPA than female mice. (PhSe)2 regulated Nrf2/Keap-1 signaling pathway and countered hepatic oxidative stress induced by BPA in male mice.

Fragment-growing guided design of Keap1-Nrf2 protein-protein interaction inhibitors for targeting myocarditis.

Small-molecule inhibitors that block the Keap1-Nrf2 protein-protein interactions are being intensely pursued as a new therapeutic strategy for oxidative stress-related diseases, such as cancer, diabetes, Alzheimer's disease, arteriosclerosis, inflammation and myocarditis. However, there are not enough studies on antioxidant treatments using small molecules in myocarditis. We herein provided a series of novel hydronaphthoquinones as the Keap1-Nrf2 interaction inhibitors targeting LPS-induced myocarditis both in vitro and in vivo. These compounds were designed through an in-silico fragment growing approach based on our previous reported compound, S47 (1). The new compounds were predicted to form additional hydrogen bonds with the S363 residue, leading to higher inhibitory activity. Among these new derivatives, compounds S01 and S05 emerged as inhibitors with significant biochemical potency, as determined by fluorescent anisotropy assay and confirmed by surface plasmon resonance (SPR) and differential scanning fluorimetry (DSF) assays. These inhibitors can dose-dependently protect the H9c2 cardiac cells against LPS-induced injury (100% at 2 µM and 4 µM) and effectively prolong survival or save the life of LPS-injured mice. Mechanistic studies showed that these inhibitors could release Nrf2 in H9c2 cells and LPS-inflammatory mouse models and translocate into the nucleus in a dose-response manner, which significantly increased the downstream genes (HO-1, NQO-1) and the pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6), while ROS production dramatically decreased. Their protective effects and the mechanism of action were further confirmed by siNrf2 transfected experiment. Collectively, the novel hydronaphthoquinones can be used as promising lead compounds for the study of Keap1-Nrf2 protein-protein interactions and further anti-myocarditis drug development.

Exenatide Increases IL-1RA Concentration and Induces Nrf-2‒Keap-1‒Regulated Antioxidant Enzymes: Relevance to ß-Cell Function.

Purpose: We previously demonstrated the anti-inflammatory and antioxidant effects of exenatide. We now hypothesized that exenatide also increases the plasma concentration of interleukin-1 receptor antagonist (IL-1RA), an endogenous anti-inflammatory protein, and modulates the nuclear factor erythroid 2‒related factor‒Kelchlike ECH-associated protein 1‒antioxidant response element (Nrf-2‒Keap-1‒ARE) system to induce key antioxidant enzymes to suppress inflammatory and oxidative stress. Methods: Twenty-four patients with obesity and type 2 diabetes receiving combined oral and insulin therapy were randomly assigned to receive either exenatide 10 µg or placebo twice a day for 12 weeks. Results: Exenatide increased IL-1RA concentration by 61% (from 318 ± 53 to 456 ± 88 pg/mL; P < 0.05). Exenatide treatment also suppressed Keap-1 protein (P < 0.05) and increased messenger RNA expression of NQO-1, glutathione S-transferase PI, heme oxygenase-1, and p21 and increased NAD(P)H dehydrogenase [quinone] 1 protein (P < 0.05) in mononuclear cells. Conclusions: Because IL-1RA protects, maintains, and stimulates ß-cell function in humans and Nrf-2‒Keap-1‒ARE protects ß cells in animals with experimental diabetes, these actions of exenatide may contribute to a potential protective effect on ß cells in diabetes.

Evaluation of the antioxidant properties of carexanes in AGS cells transfected with the Helicobacter pylori's protein HspB.

Naturally derived compounds represent a potential source of pharmacologically active drugs able to contrast different diseases, including gastric cancer, a multifactorial disease, in which the important role played by H. pylori infection has been demonstrated. Carexanes, stilbene derivatives, isolated from plants of the Carex distachya Desf., are unusual secondary metabolites with a tetracyclic skeleton arising from a cyclization of prenylstilbenoid precursors. In this study we firstly showed the ability of three purified carexanes CxB, CxG, and CxI to enhance the antioxidant response of AGS cells and to contrast the effect of the H. pylori's protein HspB. Among them CxI was the molecule that best modified the expression of genes involved in the antioxidant response. In particular, CxI was able to reduce Keap-1 gene expression and induce NQO1 gene expression, both at 4 and 24 h in AGS cells, as showed by real time PCR. Nrf2 induction was evident only at 24 h. Interestingly, the effect of CxI was stronger in HspB-transfected AGS cells, where Keap-1 gene expression was nearly abrogated. Finally, we demonstrated that CxI was able to reduce also COX-2 gene expression in HspB-transfected AGS cells, compared with untreated HspB-transfected cells, both at 4 and 24 h. This study first report that carexanes might represent candidate molecules able to contrast the deleterious effect of HspB protein but also to reduce the inflammatory process induced by H. pylori infection.