Four-Octyl itaconate ameliorates periodontal destruction via Nrf2-dependent antioxidant system / 国际口腔科学杂志·英文版

Periodontitis is a widespread oral disease characterized by continuous inflammation of the periodontal tissue and an irreversible alveolar bone loss, which eventually leads to tooth loss. Four-octyl itaconate (4-OI) is a cell-permeable itaconate derivative and has been recognized as a promising therapeutic target for the treatment of inflammatory diseases. Here, we explored, for the first time, the protective effect of 4-OI on inhibiting periodontal destruction, ameliorating local inflammation, and the underlying mechanism in periodontitis. Here we showed that 4-OI treatment ameliorates inflammation induced by lipopolysaccharide in the periodontal microenvironment. 4-OI can also significantly alleviate inflammation and alveolar bone loss via Nrf2 activation as observed on samples from experimental periodontitis in the C57BL/6 mice. This was further confirmed as silencing Nrf2 blocked the antioxidant effect of 4-OI by downregulating the expression of downstream antioxidant enzymes. Additionally, molecular docking simulation indicated the possible mechanism under Nrf2 activation. Also, in Nrf2-/- mice, 4-OI treatment did not protect against alveolar bone dysfunction due to induced periodontitis, which underlined the importance of the Nrf2 in 4-OI mediated periodontitis treatment. Our results indicated that 4-OI attenuates inflammation and oxidative stress via disassociation of KEAP1-Nrf2 and activation of Nrf2 signaling cascade. Taken together, local administration of 4-OI offers clinical potential to inhibit periodontal destruction, ameliorate local inflammation for more predictable periodontitis.

A Network Pharmacology-Based Study on Antidepressant Effect of Salicornia europaea L. Extract with Experimental Support in Chronic Unpredictable Mild Stress Model Mice / 中国结合医学杂志

OBJECTIVE@#To investigate the pharmacodynamic material basis, mechanism of actions and targeted diseases of Salicornia europaea L. (SE) based on the network pharmacology method, and to verify the antidepressant-like effect of the SE extract by pharmacological experiments.@*METHODS@#Retrieval tools including Chinese medicine (CM), PubMed, PharmMapper, MAS 3.0 and Cytoscape were used to search the components of SE, predict its targets and related therapeutic diseases, and construct the "Component-Target-Pathway" network of SE for central nervous system (CNS) diseases. Further, protein-protein interaction (PPI) network, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) function annotation of depression-related targets were analyzed to predict the antidepressant mechanism of SE. Chronic unpredictable mild stress (CUMS) model was used to construct a mouse model with depression-like symptoms. And the animals were randomly divided into 6 groups (n=10) including the normal group (nonstressed mice administered with distilled water), the CUMS group (CUMS mice administered with distilled water), the venlafaxine group (CUMS mice administered with venlafaxine 9.38 mg/kg), SE high-, medium-, and low-dose groups (CUMS mice administered with SE 1.8, 1.35 and 0.9 g/kg, respectively). Then some relevant indicators were determined for experimental verification by the forced swim test (FST), the tail suspension test (TST) and open-field test (OFT). Dopamine (DA) concentration in hippocampus and cerebral cortex, IL-2 and corticosterone (CORT) levels in blood, and nuclear factor E2 related factor 2 (Nrf2), kelch-like epichlorohydrin related protein 1 (Keap1), NAD(P) H dehydrogenase [quinone] 1 (NQO1) and heme oxygenase-1 (HO-1) levels in mice were measured by enzyme linked immunosorbent assay (ELISA) and Western blot respectively to explore the possible mechanisms.@*RESULTS@#The "target-disease" network diagram predicted by network pharmacology, showed that the potential target of SE involves a variety of CNS diseases, among which depression accounts for the majority. The experimental results showed that SE (1.8, 1.35 g/kg) significantly decreased the immobility period, compared with the CUMS group in FST and TST in mice after 3-week treatment, while SE exhibited no significant effect on exploratory behavior in OFT in mice. Compared with CUMS group, the SE group (0.9 g/kg) showed significant differences (P<0.05) in DA levels in the hippocampus and cerebral cortex. In addition, compared with CUMS control group, SE (1.8 g/kg) group showed a significant effect on decreasing the activities of CORT (P<0.05), and serum IL-2 level with no statistical significance. Finally, Western blot results showed that compared with the model group, Nrf2, Keap1, NQO1 and HO-1 protein expressions in SE group (1.8 g/kg) were up-regulated (all P<0.01).@*CONCLUSION@#The SE extract may have an antidepressant effect, which appeared to regulate Nrf2-ARE pathway and increased levels of DA and CORT in the hippocampus and cortex.

Fucoxanthin regulates Nrf2/Keap1 signaling to alleviate myocardial hypertrophy in diabetic rats / 南方医科大学学报

OBJECTIVE@#To investigate the protective effect of fucoxanthin (FX) against diabetic cardiomyopathy and explore the underlying mechanism.@*METHODS@#Rat models of diabetes mellitus (DM) induced by intraperitoneal injection of streptozotocin (60 mg/kg) were randomized into DM model group, fucoxanthin treatment (DM+FX) group and metformin treatment (DM+ Met) group, and normal rats with normal feeding served as the control group. In the two treatment groups, fucoxanthin and metformin were administered after modeling by gavage at the daily dose of 200 mg/kg and 230 mg/kg, respectively for 12 weeks, and the rats in the DM model group were given saline only. HE staining was used to examine the area of cardiac myocyte hypertrophy in each group. The expression levels of fibrotic proteins TGF-β1 and FN proteins in rat hearts were detected with Western blotting. In the cell experiment, the effect of 1 μmol/L FX on H9C2 cell hypertrophy induced by exposure to high glucose (HG, 45 mmol/L) was evaluated using FITC-labeled phalloidin. The mRNA expression levels of the hypertrophic factors ANP, BNP and β-MHC in H9C2 cells were detected using qRT-PCR. The protein expressions of Nrf2, Keap1, HO-1 and SOD1 proteins in rat heart tissues and H9C2 cells were determined using Western blotting. The DCFH-DA probe was used to detect the intracellular production of reactive oxygen species (ROS).@*RESULTS@#In the diabetic rats, fucoxanthin treatment obviously alleviated cardiomyocyte hypertrophy and myocardial fibrosis, increased the protein expressions of Nrf2 and HO-1, and decreased the protein expressions of Keap1 in the heart tissue (P < 0.05). In H9C2 cells with HG exposure, fucoxanthin significantly inhibited the enlargement of cell surface area, lowered the mRNA expression levels of ANP, BNP and β-MHC (P < 0.05), promoted Nrf2 translocation from the cytoplasm to the nucleus, and up-regulated the protein expressions its downstream targets SOD1 and HO-1 (P < 0.05) to enhance cellular antioxidant capacity and reduce intracellular ROS production.@*CONCLUSION@#Fucoxanthin possesses strong inhibitory activities against diabetic cardiomyocyte hypertrophy and myocardial fibrosis and is capable of up-regulating Nrf2 signaling to promote the expression of its downstream antioxidant proteins SOD1 and HO-1 to reduce the level of ROS.

Hyperoside protects mouse spermatocytes GC-2 cells from oxidative damage by activating the Keap1/Nrf2/HO-1 pathway / 南方医科大学学报

OBJECTIVE@#To study the protective effect of hyperoside (Hyp) against ydrogen peroxide (H2O2)- induced oxidative damage in mouse spermatocytes GC-2 cells and explore the role of the Keap1/Nrf2/HO-1 pathway in this protective mechanism.@*METHODS@#GC-2 cells were treated with 2.5 mmol/L azaacetylcysteine (NAC), 50, 100, and 200 μmol/L hyperoside, or the culture medium for 48 h before exposure to H2O2 (150 μmol/L) for 2 h. CCK-8 assay was used to detect the changes in cell viability, and cell apoptosis was analyzed using flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT) activity and malondialdehyde (MDA) in the culture medium. Western blotting and RT-qPCR were used to detect the protein and mRNA expression levels of nuclear factor erythroid 2-related factor2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), and heme oxygenase-1 (HO-1); the nuclear translocation of Nrf2 was detected using immunofluorescence assay.@*RESULTS@#Exposure to H2O2 significantly lowered the proliferation rate, reduced the activities of SOD, GSH and CAT, and obviously increased MDA content, cell apoptosis rate, and the expressions of Keap1 and Nrf2 mRNA and Keap1 protein in GC-2 cells (P < 0.05 or 0.01). Treatment of the cells prior to H2O2 exposure with either NAC or 200 μmol/L hyperoside significantly increased the cell proliferation rate, enhanced the activities of SOD, GSH-PX and CAT, and lowered MDA content and cell apoptosis rate (P < 0.05). Treatment with 200 μmol/L hyperoside significantly decreased the mRNA and protein expressions of Keap1 and increased the expressions of HO-1 mRNA and the protein expressions of Nrf2 and HO-1 (P < 0.05 or 0.01). Hyperoside also caused obvious nuclear translocation of Nrf2 in the cells (P < 0.05).@*CONCLUSION@#Hyperoside protects GC-2 cells against H2O2- induced oxidative damage possibly by activation of the Keap1/Nrf2/HO-1 signaling pathway.

Mechanism of Tibetan medicine Ershiwuwei Shanhu Pills on scopolamine-induced learning and memory impairment in mice based on Keap1/Nrf2/HO-1 signaling pathway / 中国中药杂志

This study aims to investigate the mechanism of the Tibetan medicine Ershiwuwei Shanhu Pills(ESP) in improving scopolamine-induced learning and memory impairment in mice based on Keap1/Nrf2/HO-1 signaling pathway. ICR mice were randomized into blank group, model group, low-dose(200 mg·kg~(-1)), medium-dose(400 mg·kg~(-1)), and high-dose(800 mg·kg~(-1)) ESP groups, and donepezil hydrochloride group. The learning and memory impairment was induced in mice by intraperitoneal injection of scopola-mine. The learning and memory abilities of mice were detected by Morris water maze test, and the damage of hippocampal neurons and cortical neurons was detected based on Nissl staining. The expression of neuron specific nuclear protein(NeuN) in hippocampus and cortex of mice was determined by immunofluorescence assay, and the content of acetylcholine(Ach) and the activity of acetylcholines-terase(AchE) in hippocampus of mice by kits. Moreover, the content of superoxide dismutase(SOD), malondialdehyde(MDA), catalase(CAT), and total antioxidant capacity(T-AOC) in serum of mice was detected. The content of Kelch-like ECH-associated protein 1(Keap1), nuclear factor erythroid 2-related factor 2(Nrf2), and heme oxygenase 1(HO-1) in hippocampus was determined by Western blot. The results showed that there were significant differences in the trajectory map of mice among different groups in the behavioral experiment. Moreover, the latency of ESP groups decreased significantly compared with that in the model group. The hippocampal neurons in the high-dose ESP group were significantly more than those in the model group and the cortical neurons in the high-dose and medium-dose ESP groups were significantly more than those in the model group. The expression of NeuN in the model group was significantly decreased compared with that in the blank group, and the expression in the ESP groups was significantly higher than that in the model group. The AchE activity and MDA level were significantly decreased, and Ach content and levels of SOD, CAT, and T-AOC in the ESP groups were significantly increased in the ESP groups compared with those in the model group. The expression of Keap1 in the model group was significantly increased compared with that in the blank group, and the Keap1 expression increased insignificantly in ESP groups compared with that in the model group. The expression of Nrf2 and HO-1 was significantly lower in the model group than in the blank group, and the expression was significantly higher in the medium-dose ESP group than in the model group. In conclusion, ESP protected mice against the scopolamine-induced learning and memory impairment by regulating the Keap1/Nrf2/HO-1 signaling pathway.

Mechanism of Tibetan medicine Ershiwuwei Songshi Pills against liver injury induced by acetaminophen in mice based on Keap1/Nrf2 and TLR4/NF-κB p65 signaling pathways / 中国中药杂志

The present study investigated the mechanism of the Tibetan medicine Ershiwuwei Songshi Pills(ESP) against the liver injury induced by acetaminophen(APAP) in mice based on the kelch-like ECH-associated protein 1(Keap1)/nuclear transcription factor E2 related factor 2(Nrf2) and Toll-like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB) p65 signaling pathways. Kunming mice were randomly divided into a blank control group, a model group, an N-acetyl-L-cysteine(NAC) group, and high-(400 mg·kg~(-1)), medium-(200 mg·kg~(-1)), and low-dose(100 mg·kg~(-1)) ESP groups. After 14 days of continuous administration, except for those in the control group, the mice were intraperitoneally injected with 200 mg·kg~(-1) APAP. After 12 h, the serum and liver tissues of mice were collected. Hematoxylin-eosin(HE) staining was performed on pathological sections of the liver, and the levels of aspartate aminotransferase(AST) and alanine aminotransferase(ALT) in the serum and the levels of glutathione(GSH), malondialdehyde(MDA), superoxide dismutase(SOD), catalase(CAT), myeloperoxidase(MPO), and total antioxidant capacity(T-AOC) in liver tissue homogenate were detected to observe and analyze the protective effect of ESP on APAP-induced liver injury in mice. The serum levels of tumor necrosis factor-alpha(TNF-α), interleukin-1 beta(IL-1β), and interleukin-6(IL-6) were determined by enzyme-linked immunosorbent assay(ELISA). The protein expression of Nrf2, Keap1, TLR4, and NF-κB p65 in the liver was determined by Western blot. Quantitative real-time was used to determine the mRNA expression of glutamate-cysteine ligase catalytic subunit(GCLC), glutamate-cysteine ligase regulatory subunit(GCLM), heme oxygenase-1(HO-1), and NAD(P)H dehydrogenase quinone 1(NQO-1) in the liver to explore the mechanism of ESP in improving APAP-induced liver damage in mice. As revealed by results, compared with the model group, the ESP groups showed improved liver pathological damage, decreased ALT and AST levels in the serum and MDA and MPO content in the liver, increased GSH, SOD, CAT, and T-AOC in the liver, reduced TNF-α and IL-6 levels in the serum, down-regulated expression of Keap1 in the liver cytoplasm and NF-κB p65 in the liver nucleus, up-regulated expression of Nrf2 in the liver nucleus, insignificant change in TLR4 expression, and elevated relative mRNA expression levels of antioxidant genes GCLC, GCLM, HO-1, and NQO-1. ESP can reduce the oxidative damage and inflammation caused by APAP, and the mechanism may be related to the Keap1/Nrf2 signaling pathway and the signal transduction factors on the TLR4/NF-κB p65 pathway.

Anti-oxidative and anti-apoptotic effects and molecular mechanisms of catalpol against H_2O_2-induced oxidative damage in pancreatic β cells (INS-1 cells) / 中国中药杂志

The present study investigated the anti-oxidative and anti-apoptotic effects and molecular mechanisms of catalpol on the H_2O_2-induced pancreatic β-cells(INS-1 cells).The oxidative damage model of INS-1 cells was induced and optimized by the stimulation of H_2O_2 of different concentrations for different time.CCK-8 assay was used to detect cell viability after catalpol intervention(1, 5, 10, 20, 40, 80, and 160 μmol·L~(-1)) for 24 h.Intracellular reactive oxygen species(ROS), superoxide dismutase(SOD), and lipid peroxide malondialdehyde(MDA) were measured by DCFH-DA fluorescent probe, WST-1, and TBA respectively.Moreover, the apo-ptotic effect was detected by AO-EB and Annexin V-FITC/PI staining.In addition, the protein expression levels were detected by Wes-tern blot, and intracellular insulin concentration was measured by ELISA.The results showed that the oxidative damage model of INS-1 cells was stably induced by 50 μmol·L~(-1) H_2O_2 treatment for 2 h, and catalpol at 1-80 μmol·L~(-1) did not affect cell viability of INS-1 cells.Compared with the conditions in the model group, 1, 5, and 10 μmol·L~(-1) catalpol intervention for 2 h could protect INS-1 cells from oxidative damage(P<0.001), reduce ROS and MDA, increase SOD, and inhibit excessive cell apoptosis.Moreover, 1, 5, and 10 μmol·L~(-1) catalpol could also up-regulate the phosphorylation of nuclear transcription factor NF-E2 related factors, negatively regulate Kelch-like ECH-associated protein 1(Keap1), phosphorylation of extracellular signal-regulated kinase(ERK), and heme oxyge-nase 1(HO-1), and promote the protein expression of pancreatic-duodenal homeobox factor-1(PDX-1) and glucose transporter 2(GLUT2).In addition, 1, 5, and 10 μmol·L~(-1) catalpol increased insulin secretion of INS-1 cells under oxidative damage in the high-glucose culture medium, indicating function recovery of pancreatic β cells.PDX-1 is a key nuclear transcription factor of pancreatic β cell function that directly regulates GLUT2 and insulin synthesis, and affects glucose homeostasis.In conclusion, catalpol can reduce the oxidative damage and apoptosis of INS-1 cells, activate antioxidant pathway, protect the function of pancreatic β cells, and improve insulin synthesis and secretion.

Protective effects of Polygonatum odoratum polysaccharides on alcohol-induced injury of HepG2 cells and its mechanisms / 中国应用生理学杂志

Objective: To investigate the protective effects of Polygonatum odoratum polysaccharides (POP) on alcohol-induced injury of HepG2 cells and its potential molecular mechanisms. Methods: After screening the appropriate concentration of alcohol-treated HepG2 cells and the intervention concentration of POP by MTT method, HepG2 cells were divided into three groups according to different intervention concentrations (200 μg/L, 400 μg/L and 600 μg/L) of POP, and the blank group without POP. After pretreated for 1 h, HepG2 cells were treated with 4% alcohol for 24 h. The activities of intracellular alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured, and the levels of intracellular reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), interleukin-1β (IL-1β) and tumor necrosis factor α (TNF- α) were measured. The protein expressions of Kelch-like epichlorohydrin-associated protein-1 (Keap1), phosphorylated nuclear factor E2-related factor 2 (p-Nrf2), phosphoamide adenine dinucleotide quinone oxidoreductase -1 (NQO1), B lymphocyte tumor-2 (Bcl-2), Bcl-2-associated X protein (Bax) and caspase 3 were detected. Results: Compared with the HepG2 cells treated with 4% alcohol, POP at the various concentrations could effectively down-regulate the activities of ALT and AST in HepG2 cells induced by alcohol (P＜0.05). The levels of IL-1β and TNF-α in the 200 μg/L POP treated group were decreased significantly (P＜0.05), while the level of GSH was increased significantly (P＜0.01). The levels of ROS, MDA, IL-1β and TNF-α in the 400 μg/L and 600 μg/L POP treated groups were decreased significantly (P＜0.05 or P＜0.01), while the GSH level was increased significantly (P＜0.01). POP effectively up-regulated the expressions of p-Nrf2 and NQO1 protein in HepG2 cells induced by alcohol, and also down-regulated the Bax/Bcl-2 index (P＜0.05), and inhibited the protein expressions of Keap1 and cleaved-caspase-3 (P＜0.05). Conclusion: POP can improve alcohol-induced oxidative stress injury in HepG2 cells by regulating the Nrf2/Keap1 pathway, thereby reducing the inflammatory index and apoptosis level of HepG2 cells. Among them, 400 μg/L and 600 μg/L POP have better intervention effects.

Shenlian extract attenuates TNF-α-induced ECV304 injury by regulating Nrf2/Keap1 signaling pathway / 中国中药杂志

This study aimed to investigate the effect and the possible mechanism of Shenlian( SL) extract on tumor necrosis factor-α( TNF-α)-induced ECV304 injury. After the establishment of TNF-α-induced ECV304 cells injure model,MTT assay was used to detect cell viability and the level of reactive oxygen species( ROS) was measured by flow cytometry. The contents of superoxide dismutase( SOD),malondialdehyde( MDA),nitric oxide( NO),endothelin-1( ET-1) and interleukin-1β( IL-1β) in the supernatant were detected by biochemical method and enzyme linked immunosorbent assay( ELISA). The expression levels of apoptosis-related proteins B-lymphoma-2 gene( Bcl-2),Bcl-2 associated X protein( Bax),caspase-3,caspase-9 and nuclear factor E2 associated factor2( Nrf2)/Kelch like epichlorohydrin associated protein-1( Keap1) signaling pathway related proteins Nrf2,Keap1,quinone oxidoreductase( NQO1) and heme oxygenase 1( HO-1) were detected by Western blot. The results showed that 50 μg·L-1 TNF-α significantly damaged ECV304 cells,induced the impairment of cell viability( P<0. 01),the increase of ROS production,the decrease of SOD activity,and the increase of MDA,NO,ET-1 and IL-1β( P<0. 01),meanwhile,it caused the up-regulation of Keap1,caspase-9 and Bax protein expression,and down-regulation of NQO1 and Bcl-2 protein expression( P<0. 05) compared with the control group.Compared with the model group,SL extract reduced the damage of ECV304 cells induced by TNF-α,improved cell viability,reduced ROS production,increased SOD activity and decreased MDA,NO,ET-1,IL-1β content( P<0. 01 or P<0. 05). In addition,SL extract also down-regulated the protein expression levels of Keap1,caspase-3,caspase-9 and Bax,and increased the protein expressions of Nrf2,NQO1,HO-1 and Bcl-2( P<0. 01 or P<0. 05). The above results indicate that SL extract can provide protective effect on ECV304 cells injury induced by TNF-α,alleviate oxidative stress injury,inflammation and apoptosis,and its mechanism may be related to regulating Nrf2/Keap1 signaling pathway.

Effect of Nrf2 in tumor progression and its inhibitors in cancer therapy / 中国中药杂志

Nrf2 is the key transcription factor mainly for regulating oxidative homeostasis and cytoprotective responses against oxidative stress. Nrf2/Keap1 pathway is one of the most important cellular defense mechanisms against endogenous or exogenous oxidative stress. With its activation, a wide range of stress-related genes is transactivated to restore the cellular homeostasis. Recent studies revealed that the aberrant activation of Nrf2 is related to the malignant progression, chemotherapeutic drug resistance and poor prognosis. Nrf2 plays a crucial role in cancer malignancy and chemotherapeutic resistance by controlling the intracellular redox homeostasis through the activation of cytoprotective antioxidant genes. Nrf2 inhibitor containing many natural products has been deemed as a novel therapeutic strategy for human malignancies. This article reviews the progress of studies of the Nrf2/Keap1 pathway, and its biological impact in solid malignancies and molecular mechanisms for causing Nrf2 hyperactivation in cancer cells. In conclusion, we summarized the deve-lopment of Nrf2 inhibitors in recent years, in the expectation of providing reference for further drug development and clinical studies.