OBJECTIVE To investigate the neuroprotective effects of hesperetin on central neurons under chronic high glucose,and the relationship to glyoxalase 1(Glo-1),a cytoprotective enzyme.METHODS The human neuroblas⁃toma SH-...OBJECTIVE To investigate the neuroprotective effects of hesperetin on central neurons under chronic high glucose,and the relationship to glyoxalase 1(Glo-1),a cytoprotective enzyme.METHODS The human neuroblas⁃toma SH-SY5Y cells were divided into 5 groups:normal glucose,high glucose(HG),HG plus low,middle,or high concentra⁃tion of hesperetin(1,5,25μmol·L^-1).After treatment for 72 h,neuron damages,Glo-1 expressions and functions,as well as Nrf2/ARE pathway and its regulating mechanisms were examined.RESULTS Hesperetin increased cell viability and decreased lactate dehydrogenase release,which was accompanied by the elevated activity,protein,and mRNA levels of Glo-1 as well as the enhanced Glo-1 functions in SH-SY5Y cells cultured with HG.Moreover,hesperetin activated Nrf2/ARE pathway as evidenced by the raised Nrf2 and p-Nrf2 levels in nucleus and up-regulation of γ-glutamycysteine synthase(γ-GCS),a well-known target gene of Nrf2/ARE pathway.Nevertheless,pretreatment with a PKC inhibitor(Go 6983)or an Akt inhibitor(MK-22062HCl,reflecting GSK-3β activation)abolished the effect of hesperetin on protein expressions of Glo-1 and γ-GCS.CONCLUSION Hesperetin exerted the neuroprotection by promoting Glo-1 function in central neurons in long-term HG condition,which was mediated by activation of Nrf2/ARE pathway;moreover,the increased Nrf2 phosphorylation and nuclear translocation mediated by PKC activation and/or GSK-3β inhibition were involved in the activation of Nrf2/ARE pathway by hesperetin.展开更多
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 hi...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.展开更多
基金National Natural Science Foundation of China(81371210)
文摘OBJECTIVE To investigate the neuroprotective effects of hesperetin on central neurons under chronic high glucose,and the relationship to glyoxalase 1(Glo-1),a cytoprotective enzyme.METHODS The human neuroblas⁃toma SH-SY5Y cells were divided into 5 groups:normal glucose,high glucose(HG),HG plus low,middle,or high concentra⁃tion of hesperetin(1,5,25μmol·L^-1).After treatment for 72 h,neuron damages,Glo-1 expressions and functions,as well as Nrf2/ARE pathway and its regulating mechanisms were examined.RESULTS Hesperetin increased cell viability and decreased lactate dehydrogenase release,which was accompanied by the elevated activity,protein,and mRNA levels of Glo-1 as well as the enhanced Glo-1 functions in SH-SY5Y cells cultured with HG.Moreover,hesperetin activated Nrf2/ARE pathway as evidenced by the raised Nrf2 and p-Nrf2 levels in nucleus and up-regulation of γ-glutamycysteine synthase(γ-GCS),a well-known target gene of Nrf2/ARE pathway.Nevertheless,pretreatment with a PKC inhibitor(Go 6983)or an Akt inhibitor(MK-22062HCl,reflecting GSK-3β activation)abolished the effect of hesperetin on protein expressions of Glo-1 and γ-GCS.CONCLUSION Hesperetin exerted the neuroprotection by promoting Glo-1 function in central neurons in long-term HG condition,which was mediated by activation of Nrf2/ARE pathway;moreover,the increased Nrf2 phosphorylation and nuclear translocation mediated by PKC activation and/or GSK-3β inhibition were involved in the activation of Nrf2/ARE pathway by hesperetin.
基金supported by National Natural Science Foundation of China(81371210)Qing Lan Project of Jiangsu Province(2014)Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘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.