Nuclear Nrf2 Levels Research Articles

Rolipram Rescues Memory Consolidation Deficits Caused by Sleep Deprivation: Implication of the cAMP/PKA and cAMP/Epac Pathways.

Over the last few years, the number of people suffering from sleeping disorders has increased significantly despite negative effects on cognition and an association with brain inflammation. We assessed memory deficits caused by Sleep Deprivation (SD) to determine the therapeutic effect of phosphodiesterase 4 (PDE4) inhibitors on SD-induced memory deficits and to investigate whether the modulation of memory deficits by PDE4 inhibitors is mediated by a protein kinase A (PKA)-independent pathway in conjunction with a PKA-dependent pathway. Adult male mice were divided into four groups. Three SD groups were deprived of Rapid Eye Movement (REM) sleep for 12 h a day for six consecutive days. They were tested daily in the Morris water maze to evaluate learning and memory. One of the SD groups was injected with a PDE4 inhibitor, rolipram (1 mg/kg ip), whereas another had rolipram co-administered with chlorogenic acid (CHA, 20 mg/kg ip), an inhibitor of PKA. After 6 days, the mice were sacrificed, and the hippocampi were evaluated for cyclic AMP (cAMP) and nuclear factor Nrf-2 levels. The hippocampal expression of PKA, phosphorylated cAMP Response Element-Binding Protein (CREB), and phosphorylated glycogen synthase 3β (Ser389) were also evaluated. SD caused a significant decrease in cAMP levels in the brain and had a detrimental effect on learning and memory. The administration of rolipram or rolipram+CHA resulted in an improvement in cognitive function. The present study provides evidence that restoration of memory with PDE4 inhibitors occurs through a dual mechanism involving the PKA and Epac pathways.

Curcumin Attenuates Ferroptosis-Induced Myocardial Injury in Diabetic Cardiomyopathy through the Nrf2 Pathway

Diabetes causes lipid peroxide to accumulate within cardiomyocytes. Furthermore, lipid peroxide buildup is a risk factor for ferroptosis. This study is aimed at examining whether curcumin can ameliorate ferroptosis in the treatment of diabetic cardiomyopathy. Hematoxylin and eosin and Masson sections were used to examine the morphology, arrangement, and degree of fibrosis of the myocardium of diabetic rabbit models. The expression levels of nuclear Nrf2, Gpx4, Cox1, and Acsl4 in diabetic animal and cell models were quantitatively analyzed using immunofluorescence and western blotting. Nrf2-overexpression lentivirus vectors were transfected into cardiomyocytes, and the protective effects of curcumin and Nrf2 on cardiomyocytes under high glucose stimulation were assessed using terminal deoxynucleotidyl transferase dUTP nick-end labelling and reactive oxygen species probes. Diabetes was found to disorder myocardial cell arrangement and significantly increase the degree of myocardial fibrosis and collagen expression in myocardial cells. Curcumin treatment can increase nuclear transfer of Nrf2 and the expression of Gpx4 and HO-1, reduce glucose induced myocardial cell damage, and reverse myocardial cell damage caused by the ferroptosis inducer erastin. This study confirmed that curcumin can promote the nuclear translocation of Nrf2, increase the expression of oxidative scavenging factors, such as HO-1, reduce excessive Gpx4 loss, and inhibit glucose-induced ferroptosis in cardiomyocytes. This highlights a potentially new therapeutic route for investigation for the treatment diabetic cardiomyopathy.

Nicotinamide Mononucleotide Administration Restores Redox Homeostasis via the Sirt3-Nrf2 Axis and Protects Aged Mice from Oxidative Stress-Induced Liver Injury.

Altered adaptive homeostasis contributes to aging and lifespan regulation. In the present study, to characterize the mechanism of aging in mouse liver, we performed quantitative proteomics and found that the most upregulated proteins were related to the oxidation-reduction process. Further analysis revealed that malondialdehyde (MDA) and protein carbonyl (PCO) levels were increased, while nuclear Nrf2 and downstream genes were significantly increased, indicating that oxidative stress induced Nrf2 activation in aged mouse liver. Importantly, nicotinamide mononucleotide (NMN) administration decreased the oxidative stress and the nuclear Nrf2 and Nrf2 downstream gene levels. Indeed, aged mice treated with NMN improved stress resistance against acetaminophen (APAP)-induced liver injury, indicating that NMN restored Nrf2-mediated adaptive homeostasis. Further studies found that NMN increased Sirt3 activities to deacetylate age-associated acetylation at K68 and K122 in Sod2, while its effects on nuclear Nrf2 levels were diminished in Sirt3-deficient mice, suggesting that NMN-enhanced adaptive homeostasis was Sirt3-dependent. Taken together, we demonstrated that Nrf2-regulated adaptive homeostasis was decreased in aged mouse liver and NMN supplementation restored liver redox homeostasis via the Sirt3-Nrf2 axis and protected aged liver from oxidative stress-induced injury.

Isoliquiritigenin attenuates high-fat diet-induced intestinal damage by suppressing inflammation and oxidative stress and through activating Nrf2

This study examined if isoliquiritigenin (ISL) attenuates high-fat diet (HFD)-induced intestinal damage and if this involves modulating Nrf2. Rats included 5 groups (n = 8/group): control (vehicle), ISL, HFD, HFD + ISL, and HFD + ISL + brusatol (an inhibitor of Nrf2). Treatments with the vehicle and ISL (30 mg/kg) were given orally. With no effect on intestinal lipids, ISL improved the duodenal structure in HFD rats and reduced the duodenal levels of malondialdehyde, tumor necrosis factor-α, interleukin-6, macrophage chemoattractant protein-1, and nuclear levels of NF-κB p65. Also, ISL increased the intestinal levels of superoxide dismutase, catalase, glutathione, and the cytoplasmic and nuclear levels of Nrf2. Furthermore, ISL lowered circulatory levels of lipopolysaccharides, deactivated the myosin light chain kinase (MLCK), and increased mRNA claudin-1, occluding, and zonula occludens‑1. All these effects were prevented by co-treatment of brusatol. In conclusion, ISL is a potent activator of Nrf2 intestinal inflammatory disorders.

Oxymatrine inhibits the pyroptosis in rat insulinoma cells by affecting nuclear factor kappa B and nuclear factor (erythroid-derived 2)-like 2 protein/heme oxygenase-1 pathways.

As the mechanism underlying glucose metabolism regulation by oxymatrine is unclear, this study investigated the effects of oxymatrine on pyroptosis in INS-1 cells. Flow cytometry was employed to examine cell pyroptosis and reactive oxygen species (ROS) production. Cell pyroptosis was also investigated via transmission electron microscopy and lactate dehydrogenase (LDH) release. Protein levels were detected using western blotting and interleukin (IL)-1β and IL-18 secretion by enzyme-linked immunosorbent assay. The caspase-1 activity and DNA-binding activity of nuclear factor kappa B (NF-κB) and nuclear factor (erythroid-derived 2)-like 2 protein (Nrf2) were also assessed. In the high glucose and high fat-treated INS-1 cells (HG + PA), the caspase-1 activity and LDH content, as well as Nod-like receptor family pyrin domain containing 3, Gsdmd-N, caspase-1, apoptosis-associated speck-like protein containing a CARD, IL-1β, and IL-18 levels were increased. Moreover, P65 protein levels increased in the nucleus but decreased in the cytoplasm. Oxymatrine attenuated these effects and suppressed high glucose and high fat-induced ROS production. The increased levels of nuclear Nrf2 and heme oxygenase-1 (HO-1) in the HG + PA cells were further elevated after oxymatrine treatment, whereas cytoplasmic Nrf2 and Keleh-like ECH-associated protein levels decreased. Additionally, the elevated transcriptional activity of p65 in HG + PA cells was reduced by oxymatrine, whereas that of Nrf2 increased. The results indicate that the inhibition of pyroptosis in INS-1 cells by oxymatrine, a key factor in its glucose metabolism regulation, involves the suppression of the NF-κB pathway and activation of the Nrf2/HO-1 pathway.

Wasp Venom Ameliorates Scopolamine-Induced Learning and Memory Impairment in Mice.

This study investigated the effects of wasp venom (WV) from the yellow-legged hornet, Vespa velutina, on scopolamine (SCO)-induced memory deficits in mice, as well as the antioxidant activity in HT22 murine hippocampal neuronal cells in parallel comparison with bee venom (BV). The WV was collected from the venom sac, freeze-dried. Both venoms exhibited free radical scavenging capabilities in a concentration-dependent manner. In addition, the venom treatment enhanced cell viability at the concentrations of ≤40 µg/mL of WV and ≤4 µg/mL of BV in glutamate-treated HT22 cells, and increased the transcriptional activity of the antioxidant response element (ARE), a cis-acting enhancer which regulates the expression of nuclear factor erythroid 2-related factor 2 (Nrf2)-downstream antioxidant enzymes. Concurrently, WV at 20 µg/mL significantly increased the expression of a key antioxidant enzyme heme oxygenase 1 (HO-1) in HT22 cells despite no significant changes observed in the nuclear level of Nrf2. Furthermore, the intraperitoneal administration of WV to SCO-treated mice at doses ranged from 250 to 500 µg/kg body weight ameliorated memory impairment behavior, reduced histological injury in the hippocampal region, and reduced oxidative stress biomarkers in the brain and blood of SCO-treated mice. Our findings demonstrate that WV possess the potential to improve learning and memory deficit in vivo while further study is needed for the proper dose and safety measures and clinical effectiveness.

Rumex nervosus could alleviate streptozotocin-induced diabetic nephropathy in rats by activating Nrf2 signaling.

This study tested the protective effect of Rumex nervous (R. nervosus) methanol extract against streptozotocin (STZ)-mediated type 1 diabetes mellitus (T1DM)-induced nephropathy in rats and examined if this protection involves activating the nuclear factor erythroid 2 related factor-2 (Nrf2). Rats were divided into control, R. nervous (300 mg), STZ (T1DM), STZ + R. nervosus (100, 200, or 300 mg/kg), and STZ + R. nervosus (300 mg/kg) + brusatol (an Nrf2 inhibitor). With no effect on fasting glucose and insulin levels, R. nervosus methanol extract preserved kidney histological structure and alterations kidney function markers (e.g. albumin, creatinine, and urine volume) in the STZ-diabetic rats. R. nervosus also reduced levels of reactive oxygen species (ROS), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), and interleukine-6 (IL-6), nuclear levels of the nuclear factor kappa beta (NF-κB), and mRNA of caspase-3 and Bax in the kidneys of these diabetic rats. Concomitantly, it stimulated renal mRNA levels of Bcl2 and Nrf2, cytoplasmic and nuclear levels of Nrf2, and levels of glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). All these effects were dose-dependent, with the maximum effect seen with the 300 mg/kg dose, all prevented by brusatol. Also, these effects occurred without any alteration in the transcription of the Kelch-like ECH-associated protein 1 (keap-1). Similar effects on levels of GSH, SOD, CAT, and NF-κB, as well as expression of Nrf2, were also observed in the kidney of control + R. nervous-treated rats. In conclusion, R. nervosus prevents diabetic nephropathy in rats by upregulating and activating Nrf2.

The ameliorative effect of kaempferol against CdCl2- mediated renal damage entails activation of Nrf2 and inhibition of NF-kB.

This study evaluated the nephroprotective effect of kaempferol against cadmium chloride (CdCl2) -induced nephropathy in rats. It also investigated if activation of Nrf2 is a common mechanism of action. Adult male rats ((150 ± 15g) were divided into 4 groups (n = 8/each) as a control (1% DMSO, orally), control + kaempferol (200mg/kg, orally), CdCl2 (50mg/l in drinking water), and CdCl2 + kaempferol (200mg/kg)-treated rats. All treatments were conducted for 8weeks. Kaempferol significantly attenuated CdCl2-induced weight loss, reduction in kidney weights, and the injury in the glomeruli, proximal tubules, and distal tubules in the treated rats. It also significantly lowered serum levels of urea and creatinine, increased urine output and urinary creatinine levels and clearance but reduced urinary levels of albumin urinary albumin exertion (UAER), and urinary albumin/creatinine ratio (UACR) in these rats. In parallel, kaempferol downregulated renal levels of cleaved caspase-3 and Bax and unregulated those of Bcl2. In the kidney tissues of the control animals and CdCl2 rats, kaempferol significantly attenuated oxidative stress, inflammation and significantly boosted levels of manganese superoxide dismutase and glutathione. Also, and in both groups, kaempferol suppressed the nuclear levels of NF-κB p65, downregulated Keap1, and stimulated the nuclear activation and protein levels of Nrf2. In conclusion, kaempferol is a potential therapeutic drug to prevent CdCl2-induced nephropathy due to its anti-inflammatory and anti-oxidant effects mediated by suppressing NF- NF-κB p65 and transactivating Nrf2.

6-Gingerol exerts a protective effect against hypoxic injury through the p38/Nrf2/HO-1 and p38/NF-κB pathway in H9c2 cells

Ginger, one of the most widely consumed condiment for various foods and beverages, has many pharmacological effects. 6-gingerol, a naturally occurring phenol, is one of the major pungent constituents of ginger. The purpose of this study was to characterize the effect of 6-gingerol on the p38/Nrf2/HO-1 and p38/NF-κB signaling pathway, as a possible means of combating hypoxia-related oxidative stress. H9c2 cells were chemically induced with CoCl2 to mimic hypoxia-associated cellular damage. Cardiomyocyte injury was assessed by lactate dehydrogenase and creatine kinase. Reactive oxygen species production was assessed by 2′,7′-dichlorodihydrofluorescein diacetate. The antioxidative property of 6-gingerol was measured by estimating the activities of superoxide dismutase, catalase, glutathione and glutathione disulfide. Apoptosis was detected by flow cytometry after Annexin V-FITC-propidium iodide double staining. Western blotting was used to evaluate levels of p-p38, p38, cytoplasm p65, nuclear p65, total p65, nuclear Nrf2, total Nrf2, Keap1, HIF-1α, and HO-1. 6-gingerol was able to counter hypoxia-induced cardiomyocyte injury as evidenced by inhibiting the levels of oxidative stress indexes and increasing the percentage of apoptosis. Furthermore, 6-gingerol was able to down-regulate p-p38/p38, nuclear p65, total p65 and Keap1 expression induced by CoCl2 stimulation and increased cytoplasm p65, nuclear Nrf2, total Nrf2, HO-1, and HIF-1α expression. However, treatment with specific Nrf2 inhibitor blunted the activation of Nrf2 signaling and removed the protective effects of 6-gingerol. These experiments provide evidence that 6-gingerol exerts cytoprotective effects, which may be associated with the regulation of oxidative stress and apoptosis, potentially through activating the Nrf2 pathway and inhibiting the p38/NF-κB pathways.

Maslinic Acid Protects against Streptozotocin-Induced Diabetic Retinopathy by Activating Nrf2 and Suppressing NF-κB.

This study tested the protective effect of maslinic acid (MA) against diabetic retinopathy (DR) in rats with type 1 diabetes mellitus (T1DM) and investigated possible mechanisms of action. DM was introduced by streptozotocin (STZ) (65 mg/kg, i.p.). Control and STZ (T1DM) were divided into 2 subgroups, which received either the vehicle or MA (80 mg/kg). Serum, pancreases, and retinas were collected for further use. MA significantly reduced fasting glucose levels in the control and T1DM rats but enhanced fasting insulin levels and partially increased the size of the islets of Langerhans and the number of β-cells in T1DM rats. In addition, MA significantly improved the retina structure by preventing the reduction in the area between the inner and outer limiting membranes (ILM and OLM, respectively) and increasing the number of cells forming the ganglion cell layer (GCL), inner nuclear layer (INL), and outer nuclear layer (ONL). Associated with these effects, MA significantly reduced the total levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), as well as the nuclear levels of NF-κB p65, mRNA levels of Bax, and protein levels of cleaved caspase-3 in the retinas of T1DM rats. However, MA significantly lowered levels of reactive oxygen species (ROS) and malondialdehyde (MDA) but significantly increased the nuclear levels of Nrf2, protein levels of Bcl2, and total levels of superoxide dismutase (SOD) and reduced glutathione (GSH) in the retinas of the control and T1DM rats. In conclusion, MA prevents DR by antioxidant potential mediated by the activation of Nrf2.

Korean Red Ginseng Extract Inhibits IL-8 Expression via Nrf2 Activation in Helicobacter pylori-Infected Gastric Epithelial Cells.

Helicobacter pylori (H. pylori) causes gastric diseases by increasing reactive oxygen species (ROS) and interleukin (IL)-8 expression in gastric epithelial cells. ROS and inflammatory responses are regulated by the activation of nuclear factor erythroid-2-related factor 2 (Nrf2) and the expression of Nrf2 target genes, superoxide dismutase (SOD) and heme oxygenase-1 (HO-1). We previously demonstrated that Korean red ginseng extract (RGE) decreases H. pylori-induced increases in ROS and monocyte chemoattractant protein 1 in gastric epithelial cells. We determined whether RGE suppresses the expression of IL-8 via Nrf2 activation and the expression of SOD and HO-1 in H. pylori-infected gastric epithelial AGS cells. H. pylori-infected cells were treated with RGE with or without ML385, an Nrf2 inhibitor, or zinc protoporphyrin (ZnPP), a HO-1 inhibitor. Levels of ROS and IL-8 expression; abundance of Keap1, HO-1, and SOD; levels of total, nuclear, and phosphorylated Nrf2; indices of mitochondrial dysfunction (reduction in mitochondrial membrane potential and ATP level); and SOD activity were determined. As a result, RGE disturbed Nrf2–Keap1 interactions and increased nuclear Nrf2 levels in uninfected cells. H. pylori infection decreased the protein levels of SOD-1 and HO-1, as well as SOD activity, which was reversed by RGE treatment. RGE reduced H. pylori-induced increases in ROS and IL-8 levels as well as mitochondrial dysfunction. ML385 or ZnPP reversed the inhibitory effect of RGE on the alterations caused by H. pylori. In conclusion, RGE suppressed IL-8 expression and mitochondrial dysfunction via Nrf2 activation, induction of SOD-1 and HO-1, and reduction of ROS in H. pylori-infected cells.

Quercetin protects human liver cells from o,p’-DDT-induced toxicity by suppressing Nrf2 and NADPH oxidase-regulated ROS production

Epidemiologic studies have revealed that Dichlorodiphenyltrichloroethane (DDT) and its metabolites are associated with liver diseases. However, there has been little emphasis on the mechanism underlying liver toxicity of o,p’-DDT and relevant effective inhibitors investigation. This study indicated o,p’-DDT exposure significantly decreased cell viability and promoted lactate dehydrogenase (LDH) release based on the investigation of cytotoxicity by trypan blue exclusion counts, MTT, and lactate dehydrogenase (LDH) assays. Comet, micronuclei, and DNA-protein crosslinks (DPC) assays demonstrated o,p’-DDT exposure increased the comet parameters, micronuclei frequency, and DPC coefficient. Meanwhile, we found o,p’-DDT induced mitochondria-dependent apoptosis, which is characterized by the loss of mitochondrial membrane potential (Δψm), decreased Bcl-2 expression, and increased protein levels of Bax, cytochrome c, activated-caspase-9, and activated-caspase-3. Furthermore, o,p’-DDT induced reactive oxygen species (ROS) overproduction, decreased the protein levels of nuclear factor erythroid-derived 2-like 2 (Nrf2) in the nuclear, and enhanced the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. However, quercetin treatment significantly antagonized o,p’-DDT-induced cytotoxicity, genotoxicity, and apoptosis as well as effects on ROS, Nrf2, and NADPH oxidase. Taken together, these findings suggested quercetin could alleviate o,p’-DDT-induced toxicity in HL-7702 cells via inhibiting ROS production, which is modulated by down-regulating nuclear Nrf2 levels and NADPH oxidase expression.

Urolithin A ameliorates diabetic retinopathy via activation of the Nrf2/HO-1 pathway.

Diabetic retinopathy (DR) is a progressive microvascular complication of diabetes mellitus and is characterised by excessive inflammation and oxidative stress. Urolithin A (UA), a major metabolite of ellagic acid, exerts anti-inflammatory and antioxidant functions in various human diseases. This study, for the first time, uncovered the role of UA in DR pathogenesis. Streptozotocin-induced diabetic rats were used to determine the effects of UA on blood glucose levels, retinal structures, inflammation, and oxidative stress. High glucose (HG)-induced human retinal endothelial cells (HRECs) were used to elucidate the anti-inflammatory and antioxidant mechanisms of UA in DR in vitro. The in vivo experiments demonstrated that UA injection reduced blood glucose levels, decreased albumin and vascular endothelial growth factor concentrations, and ameliorated the injured retinal structures caused by DR. UA administration also inhibited inflammation and oxidative damage in the retinal tissues of diabetic rats. Similar anti-inflammatory and antioxidant effects of UA were observed in HRECs induced by HG. Furthermore, we found that UA elevated the levels of nuclear Nrf2 and HO-1 both in vivo and in vitro. Nrf2 silencing reversed the inhibitory effects of UA on inflammation and oxidative stress during DR progression. Together, our findings indicate that UA can ameliorate DR by repressing inflammation and oxidative stress via the Nrf2/HO-1 pathway, which suggests that UA could be an effective drug for clinical DR treatment.

Isoliquiritigenin prevents Doxorubicin-induced hepatic damage in rats by upregulating and activating SIRT1

This study evaluated if the hepatic protective effect of Isoliquiritigenin (ISL) against doxorubicin (DOX)-treated rats involves upregulating sirtuin-1 (SIRT1) signaling. Adult male was divides into 5 groups (n = 6 rats/each) as control (vehicle), ISL (25 mg/kg), DOX (15 mg/kg), DOX + ISL, and DOX + ISL + EX-527 (a SIRT1 inhibitor, 5 mg/kg). ISL and EX-527 were administered 10 days before and after the single treatment of DOX. Also, cultured AML-12 hepatocytes (5 ×104) were treated with 10 µM of ISL for 24 h with or without DOX-treatments (10 µM) and in the presence or absence of EX-527 (5 µM). ISL prevented hepatocyte damage and decreased serum levels of hepatic transaminases, hepatic levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and hepatic mRNA levels of Bax and caspases-3,8, and 9. In the liver of the control and DOX-treated rats, ISL reduced levels of malondialdehyde (MDA) but increased hepatic levels of glutathione (GSH), superoxide dismutase (SOD), and catalase, as well as mRNA levels of Bcl2. In vitro, ISL stimulated cell survival and lowered levels of ROS but increased GSH levels. In vivo and in vitro, in the livers of control and DOX-treated animals, ISL significantly increased the nuclear activity and mRNA levels of SIRT1, enhanced the nuclear levels of Nrf2, and reduced nuclear levels of NF-κB p65. In conclusion, ISL alleviates DOX-induced hepatocyte toxicity by stimulating the Nrf2/antioxidants axis and concomitant suppression of NF-κB, mainly by upregulating/activating SIRT1.

Protective effect of hydrogen sulfide against stress-induced lung injury: involvement of Nrf2, NFκB/iNOS, and HIF-1α signaling pathways

Stress is a common phenomenon that is attracting increasing attention. Hydrogen sulfide (H2S) is a gasotransmitter that plays an important role in many physiological and pathological events. Our study aimed to estimate the effect and the underlying mechanisms of the H2S donor, sodium hydrosulfide (NaHS), against immobilization stress (IS)-induced lung injury. Forty adult male rats were classified into control group, NaHS group, and IS groups with and without NaHS treatment. Serum was obtained to determine corticosterone (CORT), total antioxidant capacity (TAC), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) levels. Lung H2S, nitric oxide (NO), inducible nitric oxide synthase (iNOS), and malondialdehyde (MDA) levels were measured. Lung expressions of H2S synthesizing enzymes and Western blot analysis of nuclear factor erythroid 2-related factor 2 (Nrf2) and hypoxia-inducible factor 1 alpha (HIF 1α) were estimated. Histopathological changes and immunohistochemical assessment of nuclear factor kappa B (NF-κB) and caspase-3 were also done. Pretreatment with NaHS led to marked histological protection from lung damage seen in IS rats. Furthermore, pretreatment with NaHS before IS protected lung H2S levels and expressions of H2S-synthesizing enzymes. Similarly, the levels of CORT, TNF-α, IL-10, MDA, TAC, NO, iNOS, HIF-1 α, and nuclear Nrf2 and expressions of NF-kB and caspase 3 were all maintained at near control levels in contrast to that in the IS rats. In conclusion, NaHS is protective against stress-induced lung injury due to its antioxidant, anti-inflammatory, anti-fibrotic, and antiapoptotic effects. Thus, NaHS can be used to minimize stress complications on lung.

Comparative Evaluation of Forsythiae Fructus From Different Harvest Seasons and Regions by HPLC/NIR Analysis and Anti-inflammatory and Antioxidant Assays.

Forsythiae Fructus (FF), the dry fruit of Forsythia suspensa (Thunb.) Vahl, has a long history of use in traditional Chinese Medicine for its heat-clearing and detoxifying properties. It possesses clinical therapeutic effects and biological functions showing efficacy in handling different diseases. To investigate the FF differences in Henan, Shanxi, and Shaanxi in August and October, the surface morphology, mid-infrared and near-infrared spectrums, and HPLC were analyzed. Concurrently, the anti-inflammatory and antioxidant effects on LPS-induced J774A.1 cells were evaluated by western blot and RT-qPCR. The results showed that FF from different Harvest Seasons and Regions are provided with different microstructures and mid-infrared and near-infrared spectrums, and the levels of forsythiaside A and phillyrin of FF from Shanxi in August and phillygenin of FF from Shaanxi in August were the highest. Meanwhile, FF from Shanxi and Shaanxi in August markedly reduced the levels of inflammatory cytokines and mediators (TNF-α, IL-1β, NF-κB, and iNOS) and the protein expression levels of phosphorylated total IKKα/β and nuclear NF-κB. In August, SXFF and SAXFF also promoted the mRNA expression levels of HO-1 and NQO1 and the protein expression levels of HO-1 and nuclear Nrf2 and suppressed the protein expression levels of KEAP1. Spearman correlation analysis showed that phillygenin had a strong correlation with the protein expression on LPS-induced J774A.1 cells. In summary, our results showed that FF from harvest seasons and regions contributed to the distinct differences in microstructure, the mid-infrared and near-infrared spectrums, and compound content. More importantly, FF from Shanxi and Shaanxi in August showed marked anti-inflammatory and antioxidant activities, but with some differences, which may be because of different contents of phillygenin and phillyrin of lignans in FF.

Ephedrine ameliorates cerebral ischemia injury via inhibiting NOD-like receptor pyrin domain 3 inflammasome activation through the Akt/GSK3β/NRF2 pathway.

Ischemic stroke is a leading cause of death and long-term disability worldwide. The aim of this study is to explore the potential function of ephedrine in ischemic stroke and the underlying molecular mechanism. A middle cerebral artery occlusion (MCAO) rat model was established. The potential effects of ephedrine on MCAO rats and LPS-stimulated BV2 microglial cells were evaluated. Ephedrine reduced the infarct volume, cell apoptosis, brain water content, neurological score, and proinflammatory cytokines (TNF-α and IL-1β) production in MCAO rats. Ephedrine treatment also suppressed TNF-α and IL-1β production and NOD-like receptor pyrin domain 3 (NLRP3) inflammasome activation in BV2 microglial cells. The expression of NLRP3, caspase-1, and IL-1β was suppressed by ephedrine. Moreover, ephedrine treatment increased the phosphorylation of Akt and GSK3β and nuclear NRF2 levels in LPS-treated BV2 microglial cells. Meanwhile, LY294002 attenuated the inhibitory effects of ephedrine on NLRP3 inflammasome activation and TNF-α and IL-1β production. In addition, the level of pAkt was increased, while NLRP3, caspase-1, and IL-1β were decreased by ephedrine treatment in MCAO rats. In conclusion, ephedrine ameliorated cerebral ischemia injury via inhibiting NLRP3 inflammasome activation through the Akt/GSK3β/NRF2 pathway. Our results revealed a potential role of ephedrine in ischemic stroke treatment.

Protective Effect of Chitosan Oligosaccharide against Hydrogen Peroxide-Mediated Oxidative Damage and Cell Apoptosis via Activating Nrf2/ARE Signaling Pathway.

Chitosan oligosaccharide (COS), hydrolyzed and deacetylated from chitosan, has been reported to possess varieties of biological activities. Alzheimer's disease (AD) is a multifactorial progressive neurodegenerative disorder characterized by cognitive decline and memory loss, where oxidative stress was reported to be an overwhelming cause of the occurrence of AD. We have previously reported that COS could significantly decrease cell death, ROS generation, and lipid peroxidation, though the potential mechanism was yet to be determined. This study was designed to investigate the neuroprotective effect of COS against hydrogen peroxide (H2O2)-induced oxidative stress and apoptosis in neuronal SH-SY5Y cells. Our results indicated that COS could dose-dependently scavenge H2O2 in the cell-free systems. Accordingly, COS markedly decreased H2O2-induced cell apoptosis and intracellular ROS generation, while increased antioxidant capacity in SH-SY5Y cells. Further, COS significantly reduced the expression of Bax and upregulated Bcl-2. The mRNA and protein expression levels of nuclear Nrf2, heme oxygenase 1 (HO-1), and NAD(P)H: quinone oxidoreductase 1 (NQO1) were significantly increased upon COS treatment. Moreover, Nrf2-siRNA evidently reversed the promotive effect of COS on expression levels of HO-1 and NQO1, and ARE-driven transcriptional activity as determined by double-luciferase reporter gene assay. Besides, COS reversed H2O2-mediated increased phosphorylation of ERK1/2 and p38 MAPK. In conclusion, our findings indicate that COS could protect SH-SY5Y cells from oxidative damage and apoptosis via regulating Nrf2/ARE signaling pathway, which may provide new applications for the prevention and treatment of AD.

Mitochondria-Targeted Hydrogen Sulfide Delivery Molecules Protect Against UVA-Induced Photoaging in Human Dermal Fibroblasts, and in Mouse Skin In Vivo.

Aims: Oxidative stress and mitochondrial dysfunction play a role in the process of skin photoaging via activation of matrix metalloproteases (MMPs) and the subsequent degradation of collagen. The activation of nuclear factor E2-related factor 2 (Nrf2), a transcription factor controlling antioxidant and cytoprotective defense systems, might offer a pharmacological approach to prevent skin photoaging. We therefore investigated a pharmacological approach to prevent skin photoaging, and also investigated a protective effect of the novel mitochondria-targeted hydrogen sulfide (H2S) delivery molecules AP39 and AP123, and nontargeted control molecules, on ultraviolet A light (UVA)-induced photoaging in normal human dermal fibroblasts (NHDFs) in vitro and the skin of BALB/c mice in vivo. Results: In NHDFs, AP39 and AP123 (50-200 nM) but not nontargeted controls suppressed UVA (8 J/cm2)-mediated cytotoxicity and induction of MMP-1 activity, preserved cellular bioenergetics, and increased the expression of collagen and nuclear levels of Nrf2. In in vivo experiments, topical application of AP39 or AP123 (0.3-1 μM/cm2; but not nontargeted control molecules) to mouse skin before UVA (60 J/cm2) irradiation prevented skin thickening, MMP induction, collagen loss of oxidative stress markers 8-hydroxy-2'-deoxyguanosine (8-OHdG), increased Nrf2-dependent signaling, as well as increased manganese superoxide dismutase levels and levels of the mitochondrial biogenesis marker peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α). Innovation and Conclusion: Targeting H2S delivery to mitochondria may represent a novel approach for the prevention and treatment of skin photoaging, as well as being useful tools for determining the role of mitochondrial H2S in skin disorders and aging. Antioxid. Redox Signal. 36, 1268-1288.

The antioxidant effect of preischemic dexmedetomidine in a rat model: increased expression of Nrf2/HO-1 via the PKC pathway

BackgroundThe precise underlying mechanism of antioxidant effects of dexmedetomidine-induced neuroprotection against cerebral ischemia has not yet been fully elucidated. Activation of Nuclear factor erythroid 2-related factor (Nrf2) and Heme Oxygenase-1 (HO-1) represents a major antioxidant-defense mechanism. Therefore, we determined whether dexmedetomidine increases Nrf2/HO-1 expression after global transient cerebral ischemia and assessed the involvement of Protein Kinase C (PKC) in the dexmedetomidine-related antioxidant mechanism. MethodsThirty-eight rats were randomly assigned to five groups: sham (n...=...6), ischemic (n...=...8), chelerythrine (a PKC inhibitor; 5...mg.kg-1 IV administered 30...min before cerebral ischemia) (n...=...8), dexmedetomidine (100.....g.kg-1 IP administered 30...min before cerebral ischemia (n...=...8), and dexmedetomidine...+...chelerythrine (n...=...8). Global transient cerebral ischemia (10...min) was applied in all groups, except the sham group; histopathologic changes and levels of nuclear Nrf2 and cytoplasmic HO-1 were examined 24...hours after ischemia insult. ResultsWe found fewer necrotic and apoptotic cells in the dexmedetomidine group relative to the ischemic group (p...<...0.01) and significantly higher Nrf2 and HO-1 levels in the dexmedetomidine group than in the ischemic group (p...<...0.01). Additionally, chelerythrine co-administration with dexmedetomidine attenuated the dexmedetomidine-induced increases in Nrf2 and HO-1 levels (p...<...0.05 and p...<...0.01, respectively) and diminished its beneficial neuroprotective effects. ConclusionPreischemic dexmedetomidine administration elicited neuroprotection against global transient cerebral ischemia in rats by increasing Nrf2/HO-1 expression partly via PKC signaling, suggesting that this is the antioxidant mechanism underlying dexmedetomidine-mediated neuroprotection.