High glucose reduces Nrf2-dependent cRAGE release and enhances inflammasome-dependent IL-1βproduction in monocytes:the modulatory effects of EGCG

Soluble receptor for advanced glycation end products(sRAGE)acts as a decoy sequestering of RAGE ligands,thus preventing the activation of the ligand-RAGE axis linking human diseases.However,the molecular mechanisms underlying sRAGE remain unclear.In this study,THP-1 monocytes were cultured in normal glucose(NG,5.5 mmol/L)and high glucose(HG,15 mmol/L)to investigate the effects of diabetesrelevant glucose concentrations on sRAGE and interleukin-1β(IL-1β)secretion.The modulatory effects of epigallocatechin gallate(EGCG)in response to HG challenge were also evaluated.HG enhanced intracellular reactive oxygen species(ROS)generation and RAGE expression.The secretion of sRAGE,including esRAGE and cRAGE,was reduced under HG conditions,together with the downregulation of a disintegrin and metallopeptidase 10(ADAM10)and nuclear factor erythroid 2-related factor 2(Nrf2)nuclear translocation.Mechanistically,the HG effects were counteracted by siRAGE and exacerbated by siNrf2.Chromatin immunoprecipitation results showed that Nrf2 binding to the ADAM10 promoter and HG interfered with this binding.Our data reinforce the notion that RAGE and Nrf2 might be sRAGE-regulating factors.Under HG conditions,the treatment of EGCG reduced ROS generation and RAGE activation.EGCG-stimulated cRAGE release was likely caused by the upregulation of the Nrf2-ADAM10 pathway.EGCG inhibited HG-mediated NLRP3 inflammasome activation at least partly by stimulating sRAGE,thereby reducing IL-1βrelease.

Lactobacillus plantarum J26 alleviates alcohol-induced oxidative liver injury by regulating the Nrf2 signaling pathway

Oxidative stress is one of the main ways to cause alcohol-induced liver injury,and alcoholic liver disease(ALD)has been a common health problem worldwide.Lactic acid bacteria(LAB)is also considered as a potential treatment to alleviate alcohol-induced liver injury.Lactobacillus plantarum J26 is a LAB isolated from Chinese traditional fermented dairy products with excellent probiotic effects.This study aimed to establish a mice model of alcoholic liver injury through acute-on-chronic alcohol feeding and to study the alleviating effect of pre-intake of L.plantarum J26 on alcohol-induced oxidative liver injury and focus on its potential mechanism of alleviating effect.The results showed that pre-intake of L.plantarum J26 could improve liver pathological changes,reduce lipid accumulation,increase mitochondrial ATP and mitochondrial(mtDNA)levels,and alleviate liver injury.In addition,pre-intake L.plantarum J26 can improve the level of short-chain fatty acids(SCFAs)in the intestines in mice,short chain fatty acids can be used as a signaling molecule activation of nuclear factor E2-related factor 2(Nrf2)signaling pathway to alleviate liver oxidative stress,and maintain mitochondrial homeostasis by regulating the expression of genes related to mitochondrial dynamics and autophagy,thereby reducing cell apoptosis to alleviate alcohol-induced oxidative liver injury.

Procyanidin A_1 and its digestive products alleviate acrylamide-induced IPEC-J2 cell damage through regulating Keap1/Nrf2 pathway

Our previous study has revealed that procyanidin A_(1)(A_(1))and its simulated digestive product(D-A,)can alleviate acrylamide(ACR)-induced intestine cell damage.However,the underlying mechanism remains unknown.In this study,we elucidated the molecular mechanism for and D-A_(1) to alleviate ACR-stimulated IPEC-J2 cell damage.ACR slightly activated nuclear factor erythroid 2-related factor 2(Nrf2)signaling and its target genes,but this activation could not reduce intestine cell damage.A_(1) and D-A_(1) could alleviate ACR-induced cell damage,but the effect was abrogated in cells transiently transfected with Nrf2 small interfering RNA(siRNA).Further investigation confirmed that A_(1) and D-A_(1) interacted with Ketch-like ECH-associated protein 1(Keapl),which boosted the stabilization of Nrf2,subsequently promoted the translocation of Nrf2 into the nucleus,and further increased the expression of antioxidant proteins,thereby inhibiting glutathione(GSH)consumption,maintaining redox balance and eventually alleviating ACR-induced cell damage.Importantly,there was no difference between A_(1) and D-A_(1) treated groups,indicating that A_(1) can tolerate gastrointestinal digestion and may be a potential compound to limit the toxicity of ACR.

Functionalized selenium nanoparticles ameliorated acetaminophen-induced hepatotoxicity through synergistically triggering PKCδ/Nrf2 signaling pathway and inhibiting CYP 2E1

Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative stress.Functionalized SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic activity and clinical application value.Herein,this work was conducted to investigate the protective effect of Pleurotus tuber-regium polysaccharide-protein complex funtionnalized SeNPs(PTR-SeNPs)against acetaminophen(APAP)-induced oxidative injure in HepG2 cells and C57BL/6J mouse liver.Further elucidation of the underlying molecular mechanism,in particular their modulation of Nrf2 signaling pathway was also performed.The results showed that PTR-SeNPs could significantly ameliorate APAP-induced oxidative injury as evidenced by a range of biochemical analysis,histopathological examination and immunoblotting study.PTR-SeNPs could hosphorylate and activate PKCδ,depress Keap1,and increase nuclear accumulation of Nrf2,resulting in upregulation of GCLC,GCLM,HO-1 and NQO-1 expression.Besides,PTR-SeNPs suppressed the biotransformation of APAP to generate intracellular ROS through CYP 2E1 inhibition,restoring the mitochondrial morphology.Furthermore,the protective effect of PTR-SeNPs against APAP induced hepatotoxicity was weakened as Nrf2 was depleted in vivo,indicating the pivotal role of Nrf2 signaling pathway in PTR-SeNPs mediated hepatoprotective efficacy.Being a potential hepatic protectant,PTR-SeNPs could serve as a new source of selenium supplement for health-promoting and biomedical applications.

MiR-24-3p Attenuates Doxorubicin-induced Cardiotoxicity via the Nrf2 Pathway in Mice

Objective:The nuclear factor erythroid 2(NFE2)-related factor 2(Nrf2)is associated with doxorubicin(DOX)-induced cardiac injury.It has been reported that microRNA-24-3p(miR-24-3p)may regulate the Keapl by mRNA degradation,whereas Keapl can suppress the activation of Nrf2.However,the role of miR-24-3p in DOX-related cardiotoxicity remains unclear.

Neuroprotection of quercetin on central neurons against chronic high glucose through enhancement of Nrf2/Glo-1 mediated by phosphorylation regulation

OBJECTIVE To investigate the neuroprotective effects of quercetin on central neurons against chronic high glucose in central neurons,in relation to Nrf2/ARE/Glo-1 activation.METHODS SH-SY5Y cells were cultured with high glucose(HG,70 mmol·L^(-1)),4-fold of the normal glucose(17.5 mmol·L^(-1)).Quercetin was set three concentrations(5,10,20μmol·L^(-1)),with Nrf2 activator sulforaphane(SFN)as a positive group(2.5μmol·L^(-1)).After 72 h,cells were collected for glyoxalase 1(Glo-1)activity and GSH level were by spectrophotometry;advanced glycation end-products(AGEs)as well as nuclear Nrf2 and p-Nrf2 levels by immunofluorescence;Glo-1,γ-glutamycysteine synthase(γ-GCS),Nrf2 and p-Nrf2 protein levels by Western blotting,and Glo-1 andγ-GCS m RNA levels by real-time qP CR.RESULTS Quercetin increased the cell viability of SH-SY5Y cells,and upregulated the levels of Glo-1 activity,protein,and m RNA in SH-SY5Y cells cultured with HG,accompanied by the elevated levels of glutathione,a cofactor of Glo-1 activity,and the reduced levels of AGEs.Meanwhile,quercetin could increase p-Nrf2 and Nrf2 levels in nucleus as well as p-Nrf2 levels in cytosol of SH-SY5Y cells exposed to chronic HG,accompanied by the elevated protein expression and m RNA levels ofγ-GCS,a known target gene of Nrf2/ARE signaling.Moreover,a PKC activator or a p38MAPK inhibitor pretreatment could significantly increase the protein expression ofγ-GCS in HG condition,but an alkylating agent for sulfydryl of cysteine in Keap 1,a negative regulator of Nrf2,pretreatment only showed an increased tendency ofγ-GCS protein,compared with without pretreatment;however,after pretreatment with those tool drugs,co-treatment with quercetin and HG had similar results to those of single tool drug pretreatment followed by HG exposure.CONCLUSION Firstly,quercetin can enhance Glo-1 function in central neurons,which is mediated by activation of Nrf2/ARE pathway,then exerts the neuroprotection against HG induced damage;moreover,PKC and p38 MAPK pathways may be involved in Nrf2 inactivation in chronic HG condition.

Interaction of Wnt/β-catenin and Nrf2 pathways in cigarette smoke-induced inflammation and emphysema

OBJECTIVE The present study aimed to investigate the relationship between Wnt/β-catenin and Nrf2 signaling pathways,and understanding the mechanisms underlying the process of inflammatory in chronic obstructive pulmonary disease(COPD),which was a serious disease of respiratory system.METHODS We duplicate the emphysema model with porcine pancreatic elastase(PPE)in Nrf2-/-and WT mouse for 21d,and intraperitoneal injection of Li Cl,the activator of Wnt/β-catenin signaling pathway from 14 d to the end.Hematoxylin and eosin(H&E)staining was performed to assess the histopathologic level,and immunohistochemistry(IHC)for Mac-3(the marker of macrophagocyte)and Ly6G(the marker of neutrophil)was used to observe the inflammatory infiltrate,while the levels of Wnt/β-catenin and Nrf2 signaling pathways related proteins heme oxygenase-1(HO-1),NAD(P)H:quinone oxidoreductase 1(NQO1),and the expression of inflammatory cytokine interleukin-6(IL-6)were detected by Western blotting of lung tissues.In vitro,cigarette smoke extract(CSE)-treated normal human bronchial epithelial(NHBE)cells,cell viability was examined by MTT assay,and then we treated recombinant human Wnt3a,si Nrf2 and si Wnt3a to measure the expression of Wnt3a,β-catenin,Nrf2,HO-1,NQO-1,and IL-6.Cellular immunofluorescence staining was employed to identify the nuclear translocation of Nrf2.RESULTS We found that the Li Cl-treated group has markedly decreased the damage of alveolar structure and inflammatory signs than the model group of WT mice rather than Nrf2-/-group.It also seen that Li Cl not only increasedβ-catenin,but it also led to a comparable increase in Nrf2,HO-1,NQO1,and decrease of IL-6 compared with WT model groups but except to Nrf2-/-group in vivo.And it showed that Wnt3atreatment has significantly increased the nuclear translocation of Nrf2 and the expression of HO-1 and NQO1,reduced the IL-6 release,while there has no significance when Nrf2 was blocked in CSE-induced NHBE cells.CONCLUSION Our results demonstrated that Wnt3a/β-catenin significantly balanced oxidative stress and attenuated inflammation reaction by promoting Nrf2 nuclear translocation and activity.

Oxidative stress in retinal pigment epithelium degeneration:from pathogenesis to therapeutic targets in dry age-related macular degeneration

Age-related macular degeneration is a primary cause of blindness in the older adult population. Past decades of research in the pathophysiology of the disease have resulted in breakthroughs in the form of anti-vascular endothelial growth factor therapies against neovascular age-related macular degeneration;however, effective treatment is not yet available for geographical atrophy in dry agerelated macular degeneration or for preventing the progression from early or mid to the late stage of age-related macular degeneration. Both clinical and experimental investigations involving human agerelated macular degeneration retinas and animal models point towards the atrophic alterations in retinal pigment epithelium as a key feature in age-related macular degeneration progression. Retinal pigment epithelium cells are primarily responsible for cellular-structural maintenance and nutrition supply to keep photoreceptors healthy and functional. The retinal pigment epithelium constantly endures a highly oxidative environment that is balanced with a cascade of antioxidant enzyme systems regulated by nuclear factor erythroid-2-related factor 2 as a main redox sensing transcription factor. Aging and accumulated oxidative stress triggers retinal pigment epithelium dysfunction and eventually death. Exposure to both environmental and genetic factors aggravates oxidative stress damage in aging retinal pigment epithelium and accelerates retinal pigment epithelium degeneration in age-related macular degeneration pathophysiology. The present review summarizes the role of oxidative stress in retinal pigment epithelium degeneration, with potential impacts from both genetic and environmental factors in age-related macular degeneration development and progression. Potential strategies to counter retinal pigment epithelium damage and protect the retinal pigment epithelium through enhancing its antioxidant capacity are also discussed, focusing on existing antioxidant nutritional supplementation, and exploring nuclear factor erythroid-2-related factor 2 and its regulators including REV-ERBα as therapeutic targets to protect against age-related macular degeneration development and progression.

Curcumin attenuates Nrf2 signaling defect, oxidative stress in muscle and glucose intolerance in high fat diet-fed mice

AIM: To investigate the signaling mechanism of antioxidative action by curcumin and its impact on glucose disposal. METHODS: Male C57BL/6J mice were fed with either a normal diet (n = 10) or a high fat diet (HFD) (n = 20) to induce obesity and insulin resistance. After 16 wk, 10 HFD-fed mice were further treated with daily curcumin oral gavage at the dose of 50 mg/kg body weight (BW) (HFD + curcumin group). After 15 d of the curcumin supplementation, an intraperitoneal glucose tolerance test was performed. Fasting blood samples were also collected for insulin and glucose measurements. Insulin-sensitive tissues, including muscle, adipose tissue and the liver, were isolated for the assessments of malondialdehyde (MDA), reactive oxygen species (ROS)and nuclear factor erythroid-2-related factor-2 (Nrf2) signaling. RESULTS: We show here that in a HFD mouse model, short-term curcumin gavage attenuated glucose intolerance without affecting HFD-induced BW gain. Curcumin also attenuated HFD-induced elevations of MDA and ROS in the skeletal muscle, particularly in its mitochondrial fraction, but it had no such an effect in either adipose tissue or the liver of HFD-fed mice. Correspondingly, in skeletal muscle, the levels of total or nuclear content of Nrf2, as well as its downstream target, heme oxygenase-1, were reduced by HFD-feeding. Curcumin intervention dramatically reversed these defects in Nrf2 signaling. Further analysis of the relationship of oxidative stress with glucose level by a regression analysis showed a positive and significant correlation between the area under the curve of a glucose tolerance test with MDA levels either in muscle or muscular mitochondria. CONCLUSION: These findings suggest that the shortterm treatment of curcumin in HFD-fed mice effectively ameliorates muscular oxidative stress by activating Nrf2 function that is a novel mechanism for its effect in improving glucose intolerance.

20C,a new bibenzyl compound,plays a significant role in rotenone-induced oxidative insult

20C,a bibenzyl compound isolated from Gastrodia elata,possesses antioxidative properties in PC12 cells,but its in-depth molecular mechanisms against rotenone-induced neurotoxicity remains unknown.Recent studies indicate that without intact DJ-1,nuclear factor erythroid 2-related factor(Nrf2)protein becomes unstable,and the activity of Nrf2-mediated downstream antioxidant enzymes are thereby suppressed.Therefore,increasing the nuclear translocation of Nrf2 by DJ-1 may present a helpful means for the prevention and treatment of chronic diseases related to oxidative stress.Our results showed that 20C clearly protected PC12 and SH-SY5Y cells against rotenone-induced oxidative injury in a concentration-dependent manner.Furthermore,20C markedly up-regulated the levels of DJ-1,which in turn activated phosphoinositide-3-kinase(PI3K)/Akt signaling and inhibited glycogen synthase kinase 3β(GSK3β)activation,eventually promoting Nrf2 nuclear translocation and inducing the expression of Nrf2-mediated downstream antioxidative enzymes such as HO-1.The antioxidative effects of 20C could be partially blocked by ShR NA-mediated knockdown of DJ-1 and inhibition of the PI3K/Akt pathways with Akt1/2 kinase inhibitor in PC12 and SH-SY5Y cells,respectively.Conclusively,our findings confirm that DJ-1 is necessary for 20C-mediated protection against rotenone-induced oxidative damage,at least in part,by activating PI3K/Akt signaling,and subsequently enhancing the nuclear accumulation of Nrf2.The findings from our investigation suggest that 20C should be developed as a novel candidate for preventing or alleviating the consequences of PD in the future.

Nrf2-mediated ferroptosis of spermatogenic cells involved in male reproductive toxicity induced by polystyrene nanoplastics in mice

Microplastics(MPs)and nanoplastics(NPs)have become hazardous materials due to the massive amount of plastic waste and disposable masks,but their specific health effects remain uncertain.In this study,fluorescence-labeled polystyrene NPs(PS-NPs)were injected into the circulatory systems of mice to determine the distribution and potential toxic effects of NPs in vivo.Interestingly,whole-body imaging found that PS-NPs accumulated in the testes of mice.Therefore,the toxic effects of PS-NPs on the reproduction systems and the spermatocytes cell line of male mice,and their mechanisms,were investigated.After oral exposure to PS-NPs,their spermatogenesis was affected and the spermatogenic cells were damaged.The spermatocyte cell line GC-2 was exposed to PS-NPs and analyzed using RNA sequencing(RNA-seq)to determine the toxic mechanisms;a ferroptosis pathway was found after PS-NP exposure.The phenomena and indicators of ferroptosis were then determined and verified by ferroptosis inhibitor ferrostatin-1(Fer-1),and it was also found that nuclear factor erythroid 2-related factor 2(Nrf2)played an important role in spermatogenic cell ferroptosis induced by PS-NPs.Finally,it was confirmed in vivo that this mechanism of Nrf2 played a protective role in PS-NPs-induced male reproductive toxicity.This study demonstrated that PS-NPs induce male reproductive dysfunction in mice by causing spermatogenic cell ferroptosis dependent on Nrf2.

Engineered Bacillus subtilis alleviates intestinal oxidative injury through Nrf2-Keap1 pathway in enterotoxigenic Escherichia coli(ETEC) K88-infected piglet

Engineered probiotics can serve as therapeutics based on their ability of produce recombinant immune-stimulating properties.In this study,we built the recombinant Bacillus subtilis WB800 expressing antimicrobial peptide KR32(WB800-KR32)using genetic engineering methods and investigated its protective effects of nuclear factor-E2-related factor 2(Nrf2)-Kelch-like ECH-associated protein 1(Keap1)pathway activation in intestinal oxidative disturbance induced by enterotoxigenic Escherichia coli(ETEC)K88 in weaned piglets.Twenty-eight weaned piglets were randomly distributed into four treatment groups with seven replicates fed with a basal diet.The feed of the control group(CON)was infused with normal sterilized saline;meanwhile,the ETEC,ETEC+WB800,and ETEC+WB800-KR32 groups were orally administered normal sterilized saline,5×10^(10)CFU(CFU:colony forming units)WB800,and 5×10^(10)CFU WB800-KR32,respectively,on Days 1-14 and all infused with ETEC K881×10^(10)CFU on Days 15-17.The results showed that pretreatment with WB800-KR32 attenuated ETEC-induced intestinal disturbance,improved the mucosal activity of antioxidant enzyme(catalase(CAT),superoxide dismutase(SOD),and glutathione peroxidase(GPx))and decreased the content of malondialdehyde(MDA).More importantly,WB800-KR32 downregulated genes involved in antioxidant defense(GPx and SOD1).Interestingly,WB800-KR32 upregulated the protein expression of Nrf2 and downregulated the protein expression of Keap1 in the ileum.WB800-KR32 markedly changed the richness estimators(Ace and Chao)of gut microbiota and increased the abundance of Eubacterium_rectale_ATCC_33656 in the feces.The results suggested that WB800-KR32 may alleviate ETEC-induced intestinal oxidative injury through the Nrf2-Keap1 pathway,providing a new perspective for WB800-KR32 as potential therapeutics to regulate intestinal oxidative disturbance in ETEC K88 infection.

Saeng-Kankunbi-Tang(生肝健脾汤) Protects Liver against Oxidative Damage through Activation of ERK/Nrf2 Pathway

Objective： To investigate the cytoprotective effects of Saeng-kankunbi-tang（生肝健脾汤, SKT）, a herbal prescription consisting of Artemisia capillaris and Alisma canaliculatum, and its underlying mechanism involved. Methods： In mice, blood biochemistry and histopathology were assessed in carbon tetrachloride（CCl4）-induced oxidative hepatic injury in vivo. The animal groups included vehicle-treated control, CCl4, SKT 500 mg/（kg·day） CCl4＋SKT 200 or 500 mg/（kg·day）. In Hep G2 cell, tert-butyl hydroperoxide（t BHP） induced severe oxidative stress and mitochondrial dysfunction in vitro. The cyto-protective effects of SKT were determined by 3-（4,5-dimethylthiazol）-2,5-diphenyltetrazolium bromide（MTT） assay, fluorescence activated cell sorting analysis and western blotting. Results： The administration of SKT prevented liver damage induced by CCl4 in mice, by inhibition of hepatocyte degeneration and inflammatory cell infiltration as well as plasma parameters such as alanine aminotransferase（P〈0.01）. Moreover, treatment with t BHP induced hepatocyte death and cellular reactive oxygen species production in hepatocyte cell line. However, SKT pretreatment（30–300 μg/m L） reduced this cell death and oxidative stress（P〈0.01）. More importantly, SKT inhibited the ability of t BHP to induce changes in mitochondrial membrane transition in cell stained with rhodamine 123（P〈0.01）. Furthermore, treatment with SKT induced extracellular signal-regulated kinases-mediated nuclear factor erythroid-2-related factor 2（Nrf2） activation as well as the expressions of heme oxygenase 1 and glutamate-cystein ligase catalytic, Nrf2 target genes. Conclusion： SKT has the ability to protect hepatocyte against oxidative stress and mitochondrial damage mediated by Nrf2 activation.

Biological insights in non-small cell lung cancer

Lung oncogenesis relies on intracellular cysteine to overcome oxidative stress.Several tumor types,including non-small cell lung cancer(NSCLC),upregulate the system x-c cystine/glutamate antiporter(xCT)through overexpression of the cystine transporter SLC7A11,thus sustaining intracellular cysteine levels to support glutathione synthesis.Nuclear factor erythroid 2-related factor 2(NRF2)serves as a master regulator of oxidative stress resistance by regulating SLC7A11,whereas Kelch-like ECH-associated protein(KEAP1)acts as a cytoplasmic repressor of the oxidative responsive transcription factor NRF2.Mutations in KEAP1/NRF2 and p53 induce SLC7A11 activation in NSCLC.Extracellular cystine is crucial in supplying the intracellular cysteine levels necessary to combat oxidative stress.Disruptions in cystine availability lead to iron-dependent lipid peroxidation,thus resulting in a type of cell death called ferroptosis.Pharmacologic inhibitors of xCT(either SLC7A11 or GPX4)induce ferroptosis of NSCLC cells and other tumor types.When cystine uptake is impaired,the intracellular cysteine pool can be sustained by the transsulfuration pathway,which is catalyzed by cystathionine-B-synthase(CBS)and cystathionine g-lyase(CSE).The involvement of exogenous cysteine/cystine and the transsulfuration pathway in the cysteine pool and downstream metabolites results in compromised CD8^(+)T cell function and evasion of immunotherapy,diminishing immune response and potentially reducing the effectiveness of immunotherapeutic interventions.Pyroptosis is a previously unrecognized form of regulated cell death.In NSCLCs driven by EGFR,ALK,or KRAS,selective inhibitors induce pyroptotic cell death as well as apoptosis.After targeted therapy,the mitochondrial intrinsic apoptotic pathway is activated,thus leading to the cleavage and activation of caspase-3.Consequently,gasdermin E is activated,thus leading to permeabilization of the cytoplasmic membrane and cell-lytic pyroptosis(indicated by characteristic cell membrane ballooning).Breakthroughs in KRAS G12C allele-specific inhibitors and potential mechanisms of resistance are also discussed herein.

Therapeutic detoxification of quercetin against carbon tetrachloride-induced acute liver injury in mice and its mechanism

This study observes the therapeutic detoxification of quercetin, a well-known flavonoid, against carbon tetrachlodde （CCI4） induced acute liver injury in vivo and explores its mechanism. QuerceUn decreased CCI4-increased serum activities of alanine and aspartate aminotransferases （ALT/AST） when orally taken 30 min after CCI4 intoxica- tion. The results of a histological evaluation further evidenced the ability of quercetin to protect against CCI4-induced liver injury. Quercetin decreased the CCI4-increased malondialdehyde （MDA） and reduced the glutathione （GSH） amounts in the liver. It also reduced the enhanced immunohistochemical staining of the 4-hydroxynonenal （4-HNE） in the liver induced by CCI4. Peroxiredoxin （Prx） 1, 2, 3, 5, 6, thioredoxin reductase 1 and 2 （TrxRl/2）, thioredoxin 1 and 2 （Trxl/2）, nuclear factor erythroid 2-related factor 2 （Nrf2）, and heme oxygenase-1 （HO-1） all play critical roles in maintaining cellular redox homeostasis. Real-time polymerase chain reaction （PCR） results demonstrated that quercetin reversed the decreased mRNA expression of all those genes induced by CCI4. In conclusion, our results demonstrate that quercetin ameliorates CCI4-induced acute liver injury in vivo via alleviating oxidative stress injuries when orally taken after CCI4 intoxication. This protection may be caused by the elevation of the antioxidant capacity induced by quercetin.

Pre-treatment twice with liposomal clodronate protects against acetaminophen hepatotoxicity through a pre-conditioning effect

Background and aim:Acetaminophen(APAP)overdose is a major cause of acute liver injury,but the role of macrophages in the propagation of the hepatotoxicity is controversial.Early research revealed that macrophage inhibitors protect against APAP injury.However,later work demonstrated that macrophage ablation by acute pre-treatment with liposomal clodronate(LC)exacerbates the toxicity.To our surprise,during other studies,we observed that pre-treatment twice with LC seemed to protect against APAP hepatotoxicity,in contrast to acute pre-treatment.The aim of this study was to confirm that observation and to explore the mechanisms.Methods:We treated mice with empty liposomes(LE)or LC twice per week for 1 week before APAP overdose and collected blood and liver tissue at 0,2,and 6 h post-APAP.We then measured liver injury(serum alanine aminotransferase activity,histology),APAP bioactivation(total glutathione,APAP-protein adducts),oxidative stress(oxidized glutathione(GSSG)),glutamate-cysteine ligase subunit c(Gclc)mRNA,and nuclear factor erythroid 2-related factor(Nrf2)immunofluorescence.We also confirmed the ablation of macrophages by F4/80 immunohistochemistry.Results:Pre-treatment twice with LC dramatically reduced F4/80 staining,protected against liver injury,and reduced oxidative stress at 6 h post-APAP,without affecting APAP bioactivation.Importantly,Gclc mRNA was higher in the LC group at 0 h and total glutathione was higher at 2 h,indicating accelerated glutathione re-synthesis after APAP overdose due to greater basal glutamate-cysteine ligase.Oxidative stress was lower in the LC groups at both time points.Finally,total Nrf2 immunofluorescence was higher in the LC group.Conclusions:We conclude that multiple pre-treatments with LC protect against APAP by accelerating glutathione re-synthesis through glutamate-cysteine ligase.Investigators using twice or possibly more LC pre-treatments to deplete macrophages,including peritoneal macrophages,should be aware of this possible confounder.

Effects of sulforaphane on brain mitochondria: mechanistic view and future directions

The organosulfur compound sulforaphane(SFN;C6H11NOS2) is a potent cytoprotective agent promoting antioxidant, anti-inflammatory, antiglycative, and antimicrobial effects in in vitro and in vivo experimental models. Mitochondria are the major site of adenosine triphosphate(ATP) production due to the work of the oxidative phosphorylation(OXPHOS) system. They are also the main site of reactive oxygen species(ROS) production in nucleated human cells. Mitochondrial impairment is central in several human diseases, including neurodegeneration and metabolic disorders. In this paper, we describe and discuss the effects and mechanisms of action by which SFN modulates mitochondrial function and dynamics in mammalian cells. Mitochondria-related pro-apoptotic effects promoted by SFN in tumor cells are also discussed. SFN may be considered a cytoprotective agent, at least in part, because of the effects this organosulfur agent induces in mitochondria. Nonetheless, there are certain points that should be addressed in further experiments, indicated here as future directions, which may help researchers in this field of research.