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
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...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.展开更多
BACKGROUND Enterotoxigenic Bacteroides fragilis(ETBF)causes colitis and diarrhea,and is considered a candidate pathogen in inflammatory bowel diseases as well as colorectal cancers.These diseases are dependent on ETBF...BACKGROUND Enterotoxigenic Bacteroides fragilis(ETBF)causes colitis and diarrhea,and is considered a candidate pathogen in inflammatory bowel diseases as well as colorectal cancers.These diseases are dependent on ETBF-secreted toxin(BFT).Dendritic cells(DCs)play an important role in directing the nature of adaptive immune responses to bacterial infection and heme oxygenase-1(HO-1)is involved in the regulation of DC function.AIM To investigate the role of BFT in HO-1 expression in DCs.METHODS Murine DCs were generated from specific pathogen-free C57BL/6 and Nrf2−/−knockout mice.DCs were exposed to BFT,after which HO-1 expression and the related signaling factor activation were measured by quantitative RT-PCR,EMSA,fluorescent microscopy,immunoblot,and ELISA.RESULTS HO-1 expression was upregulated in DCs stimulated with BFT.Although BFT activated transcription factors such as NF-κB,AP-1,and Nrf2,activation of NF-κB and AP-1 was not involved in the induction of HO-1 expression in BFT-exposed DCs.Instead,upregulation of HO-1 expression was dependent on Nrf2 activation in DCs.Moreover,HO-1 expression via Nrf2 in DCs was regulated by mitogenactivated protein kinases such as ERK and p38.Furthermore,BFT enhanced the production of reactive oxygen species(ROS)and inhibition of ROS production resulted in a significant decrease of phospho-ERK,phospho-p38,Nrf2,and HO-1 CONCLUSION These results suggest that signaling pathways involving ROS-mediated ERK and p38 mitogen-activated protein kinases-Nrf2 activation in DCs are required for HO-1 induction during exposure to ETBF-produced BFT.展开更多
Air pollution is fourth major cause of death worldwide.Recent evidence suggests that particulate matter(PM)may affect kidneys,and the effect may be size and composition dependent.In this study,PM_(0.1),PM_(2.5),and PM...Air pollution is fourth major cause of death worldwide.Recent evidence suggests that particulate matter(PM)may affect kidneys,and the effect may be size and composition dependent.In this study,PM_(0.1),PM_(2.5),and PM_(10)were collected from ambient air and given to BALB/c male mice at 0.25 mg/m^(3) concentration in whole-body inhalation chamber for 28days(6 h/day,5 days/week)to assess their effect on kidney.Physico-chemical characterization of PM particles by SEM,ICP-MS and HPLC showed their various shapes along with the presence of metals and poly aromatic hydrocarbons(PAHs).Following PM exposure,increased serum creatinine levels were observed in animals along with dilated tubules,protein cast deposition,necrosis,immune infiltration,collagen deposition,and shrunken glomeruli in kidney.Immunofluorescence staining showed higher expressions of kidney injury molecule1(KIM-1),cystatin C,β2 microglobulin(β2M),and alpha smooth muscle actin(α-SMA)and fibronectin,suggesting renal injury and fibrosis.PM exposure also increased malondialdehyde(MDA)content and decreased superoxide dismutase 2(SOD2)activity,which in turn leads to induction of inflammation.Mechanistically,PM exposure further inhibited the nuclear factor erythroid 2-related factor 2(Nrf2)signalling and induced kelch-like ECH-associated protein 1(Keap1)and nuclear factor kappa-light-chain-enhancer of activated B(NF-κB).Interestingly,the effect of PM_(2.5)was more severe than PM_(0.1)and PM_(10),leading to higher levels of proinflammatory NF-κB and greater Nrf2 inhibition.Overall,our findings suggested that inhalation exposure to size-segregated PM can cause kidney damage and fibrosis,and PM_(2.5)showed higher toxicity than PM_(0.1)and PM_(10).展开更多
Small RNAs(sRNAs)are essential for regulating plant growth and development,and they possess the notable ability to travel long distances within organisms to regulate target gene expression.Our study examined the dcl2 ...Small RNAs(sRNAs)are essential for regulating plant growth and development,and they possess the notable ability to travel long distances within organisms to regulate target gene expression.Our study examined the dcl2 mutant,a key enzyme in s RNA biogenesis,to determine the role of the DCL2 protein in s RNA synthesis and to identify mobile s RNAs under DCL2 regulation.Through grafting experiments between dcl2 mutants and wild-type soybean plants,coupled with s RNA sequencing,we identified14,105 s RNAs significantly affected by DCL2 and discovered 375 mobile s RNAs under its regulation.Degradome analysis provided deeper insights into the regulatory effects of these mobile s RNAs on their target genes,enabling us to understand their potential influences on plant development and stress responses.Leveraging the systemic movement of s RNAs from roots to shoots,we propose a novel strategy for manipulating gene expression in aboveground tissues.Overall,our research findings not only deepen our understanding of the complex regulatory networks involving mobile s RNAs regulated by DCL2,but also provide a new strategy for gene regulation,which could have a positive impact on agricultural biotechnology.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 National Natural Science Foundation of China (31971282 and 32071362)2019 Chongqing Graduate Tutor Team Construction Project (dstd201903)Scientific and Technological Research Program of Chongqing Municipal Education Commission (KJQN201900415)。
文摘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.
基金Supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education,Science and Technology,South Korea,No.NRF-2018R1D1A1B07043350
文摘BACKGROUND Enterotoxigenic Bacteroides fragilis(ETBF)causes colitis and diarrhea,and is considered a candidate pathogen in inflammatory bowel diseases as well as colorectal cancers.These diseases are dependent on ETBF-secreted toxin(BFT).Dendritic cells(DCs)play an important role in directing the nature of adaptive immune responses to bacterial infection and heme oxygenase-1(HO-1)is involved in the regulation of DC function.AIM To investigate the role of BFT in HO-1 expression in DCs.METHODS Murine DCs were generated from specific pathogen-free C57BL/6 and Nrf2−/−knockout mice.DCs were exposed to BFT,after which HO-1 expression and the related signaling factor activation were measured by quantitative RT-PCR,EMSA,fluorescent microscopy,immunoblot,and ELISA.RESULTS HO-1 expression was upregulated in DCs stimulated with BFT.Although BFT activated transcription factors such as NF-κB,AP-1,and Nrf2,activation of NF-κB and AP-1 was not involved in the induction of HO-1 expression in BFT-exposed DCs.Instead,upregulation of HO-1 expression was dependent on Nrf2 activation in DCs.Moreover,HO-1 expression via Nrf2 in DCs was regulated by mitogenactivated protein kinases such as ERK and p38.Furthermore,BFT enhanced the production of reactive oxygen species(ROS)and inhibition of ROS production resulted in a significant decrease of phospho-ERK,phospho-p38,Nrf2,and HO-1 CONCLUSION These results suggest that signaling pathways involving ROS-mediated ERK and p38 mitogen-activated protein kinases-Nrf2 activation in DCs are required for HO-1 induction during exposure to ETBF-produced BFT.
基金supported by the institutional fund MLP004 and Science and Engineering Research Board(SERB)(No.CRG/2021/002625)financial assistance from DBT-JRF,Department of Biotechnology,Gov of India,New Delhi India(DBT/2018/1111)。
文摘Air pollution is fourth major cause of death worldwide.Recent evidence suggests that particulate matter(PM)may affect kidneys,and the effect may be size and composition dependent.In this study,PM_(0.1),PM_(2.5),and PM_(10)were collected from ambient air and given to BALB/c male mice at 0.25 mg/m^(3) concentration in whole-body inhalation chamber for 28days(6 h/day,5 days/week)to assess their effect on kidney.Physico-chemical characterization of PM particles by SEM,ICP-MS and HPLC showed their various shapes along with the presence of metals and poly aromatic hydrocarbons(PAHs).Following PM exposure,increased serum creatinine levels were observed in animals along with dilated tubules,protein cast deposition,necrosis,immune infiltration,collagen deposition,and shrunken glomeruli in kidney.Immunofluorescence staining showed higher expressions of kidney injury molecule1(KIM-1),cystatin C,β2 microglobulin(β2M),and alpha smooth muscle actin(α-SMA)and fibronectin,suggesting renal injury and fibrosis.PM exposure also increased malondialdehyde(MDA)content and decreased superoxide dismutase 2(SOD2)activity,which in turn leads to induction of inflammation.Mechanistically,PM exposure further inhibited the nuclear factor erythroid 2-related factor 2(Nrf2)signalling and induced kelch-like ECH-associated protein 1(Keap1)and nuclear factor kappa-light-chain-enhancer of activated B(NF-κB).Interestingly,the effect of PM_(2.5)was more severe than PM_(0.1)and PM_(10),leading to higher levels of proinflammatory NF-κB and greater Nrf2 inhibition.Overall,our findings suggested that inhalation exposure to size-segregated PM can cause kidney damage and fibrosis,and PM_(2.5)showed higher toxicity than PM_(0.1)and PM_(10).
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA24010205)the CAS Project for Young Scientists in Basic Research(YSBR-011)+1 种基金National Natural Science Foundation of China(32272101)the Agricultural Science and Technology Innovation Program of CAAS。
文摘Small RNAs(sRNAs)are essential for regulating plant growth and development,and they possess the notable ability to travel long distances within organisms to regulate target gene expression.Our study examined the dcl2 mutant,a key enzyme in s RNA biogenesis,to determine the role of the DCL2 protein in s RNA synthesis and to identify mobile s RNAs under DCL2 regulation.Through grafting experiments between dcl2 mutants and wild-type soybean plants,coupled with s RNA sequencing,we identified14,105 s RNAs significantly affected by DCL2 and discovered 375 mobile s RNAs under its regulation.Degradome analysis provided deeper insights into the regulatory effects of these mobile s RNAs on their target genes,enabling us to understand their potential influences on plant development and stress responses.Leveraging the systemic movement of s RNAs from roots to shoots,we propose a novel strategy for manipulating gene expression in aboveground tissues.Overall,our research findings not only deepen our understanding of the complex regulatory networks involving mobile s RNAs regulated by DCL2,but also provide a new strategy for gene regulation,which could have a positive impact on agricultural biotechnology.
文摘目的探究枸杞多糖(Lycium barbarum polysaccharides,LBP)调控核因子E2相关因子2(nuclear factor E2 related factor 2,Nrf2)/谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4)通路对缺氧/复氧(hypoxia/reoxygenation,H/R)诱导的心肌细胞铁死亡的影响。方法设置对照组、模型组及LBP低、中、高剂量(25、50、100 mg/L)组和LBP(100mg/L)+Nrf2抑制剂ML385(5μmol/L)组。构建H9c2细胞H/R模型,并给予相应药物处理。采用CCK-8检测细胞活力;采用TUNEL染色检测细胞凋亡;采用试剂盒检测细胞Fe^(2+)、谷胱甘肽(glutathione,GSH)、丙二醛(malondialdehyde,MDA)水平及乳酸脱氢酶(lactate dehydrogenase,LDH)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)活性;采用二氢乙锭(dihydroethidium,DHE)荧光探针检测细胞活性氧(reactive oxygen species,ROS)水平;采用透射电镜观察细胞线粒体形态;采用Western blotting检测转铁蛋白受体1(transferrin receptor 1,Tf R1)、二价金属离子转运蛋白1(divalent metal transporter 1,DMT1)、铁蛋白重链1(ferritin heavy chain 1,FTH1)、酰基辅酶A合成酶长链家族成员4(acyl-CoA synthetase long-chain family member 4,ACSL4)、Kelch样ECH相关蛋白1(Kelch like ECH associated protein1,Keap1)、Nrf2、血红素氧合酶-1(heme oxygenase-1,HO-1)、溶质载体家族7成员11(solute carrier family 7 member 11,SLC7A11)、GPX4蛋白表达。结果与对照组比较,模型组细胞活力显著降低(P<0.001),Fe^(2+)、MDA、ROS水平和LDH活性显著升高(P<0.001),GSH水平和SOD、CAT活性显著降低(P<0.001),线粒体缩短、膜密度增高且嵴数量减少,TfR1、Nrf2、HO-1、SLC7A11、GPX4蛋白表达水平显著降低(P<0.001),DMT1、FTH1、ACSL4、Keap1蛋白表达水平显著升高(P<0.001)。与模型组比较,LBP组细胞活力显著升高(P<0.01),Fe^(2+)、MDA、ROS水平和LDH活性显著降低(P<0.05、0.01、0.001),GSH水平和SOD、CAT活性显著升高(P<0.05、0.01、0.001),线粒体形态较为规则,TfR1、Nrf2、HO-1、SLC7A11、GPX4蛋白表达水平显著升高(P<0.01、0.001),DMT1、FTH1、ACSL4、Keap1蛋白表达水平显著降低(P<0.05、0.01、0.001);而ML385能够抑制枸杞多糖对细胞铁死亡的改善作用(P<0.05、0.01、0.001)。结论枸杞多糖可能通过激活Nrf2/GPX4通路改善H/R诱导的心肌细胞铁死亡。
