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 un...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.展开更多
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 thi...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.展开更多
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 indica...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.展开更多
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 overexp...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.展开更多
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-incr...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.展开更多
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 inhib...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.展开更多
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. Mi...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.展开更多
文摘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.
基金supported by the project from National Natural Science Foundation of China (31671962)Fundamental Research Funds for the Central Universities (2662019PY034)。
文摘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.
基金supported by National Natural Science Foundation of China(U1402221,81573640,81603316)Beijing Natural Science Foundation(7161011)+3 种基金CAMS Innovation Fund for Medical Sciences(CIFMS)(2016-I2M-1-004)Beijing Key Laboratory of New Drug Mechanisms and Pharmacological Evaluation Study(BZ0150)Key Research and Development Project of Hunan Province(2015SK2029-1)Scientific Research Foundation of the Higher Education Institutions of Hunan Province(15K091)
文摘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.
基金supported by a Spanish Association Against Cancer(AECC)grant,(grant No.PROYE18012ROSE)support from Julián Santamaría Vali?o to the IOR Foundation。
文摘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.
基金Project supported by the "Shu Guang" Project from Shanghai Municipal Education Commission and Shanghai Education Development Foundation(No.13SG43)the National Natural Science Foundation of China(No.81322053)the Program for New Century Excellent Talents in University(No.NCET-11-1054),China
文摘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.
基金This work was supported by the American Association for the Study of Liver Diseases Foundation,Alexandria,VA,USA(2018 Pinnacle Research Award)by the United States National Institutes of Health(grant numbers T32 GM106999,UL1 TR003107,R42 DK079387 and KL2 TR003108).
文摘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.
基金Project supported by the National Council for Scientific and Technological Development(CNPq,No.301273/2018-9),Brazil。
文摘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.
