Tau oligomers are the etiologic molecules of Alzheimer disease(AD), and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic a...Tau oligomers are the etiologic molecules of Alzheimer disease(AD), and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic aggregate species. The aim of the present study was to investigate the mechanisms of cornel iridoid glycoside(CIG) on tau oligomers and cognitive functions. We injected wortmannin and GF-109203 X(WM/GFX, 200 μmol·L-1 each) into the lateral ventricles to induce tau oligomer and memory impairment in rats. When oral y administered with CIG at 60 and 120 mg·kg-1 per day for 14 d, CIG decreased the escape latency in Morris water maze test. We also found that CIG restored the expression of presynaptic p-synapsin, synaptophysin, and postsynaptic density-95(PSD-95) decreased by WM/GFX in rat cortex. CIG reduced the accumulation of tau oligomers in the brain of WM/GFX rats and in cells transfected with wild type glycogen synthase kinase-3β(wt GSK-3β). In addition, CIG up-regulated the levels of ATG7, ATG12, Beclin-1, and LC3 II in vivo and in vitro, suggesting the restoration of autophagy function. These results suggest that CIG could ameliorate memory deficits and regulate memory-associated synaptic proteins through the clearance of tau oligomers accumulation. Moreover, CIG clears tau oligomers by restoring autophagy function.展开更多
Alzheimer’s disease(AD),also defined as a tauopathology,is a common neurodegenerative disease.Hyper-phosphorylation,cleavage or truncation,and aggregation of tau contribute to AD.Thus,targeting the post-translational...Alzheimer’s disease(AD),also defined as a tauopathology,is a common neurodegenerative disease.Hyper-phosphorylation,cleavage or truncation,and aggregation of tau contribute to AD.Thus,targeting the post-translational modifications on tau may be a therapeutic strategy to treat AD.This study understood how cornel iridoid glycoside(CIG)affects tau post-translational modifications and synaptic abnormalities.The 10-month old P301S tau transgenic mice were given CIG at 100 and 200 mg/kg every day orally for 1 month.Hyperphosphorylated and truncated tau,synapse-associated proteins and glutamatergic receptors were all detected using Western blotting.The interactions between Morroniside(MOR)or Loganin(LOG)and tau were detected using Autodock and Surface Plasmon Resonance(SPR).The effects of CIG on the aggregation of tau were investigated using a cell-free system.CIG attenuated tau hyperphosphorylation at Thr205,Ser212,Ser262,Thr231 and Ser235(AT180),but had no effect on tau truncation in the brains of 10-month old P301S mice.Binding free energies and interactions revealed that MOR and LOG bound with tau.We also found that CIG upregulated synapse-associated proteins such as PSD-95,syntaxin1A and synaptotagmin.In addition,CIG restored N-methyl-D-aspartic acid receptor and glutamate receptor levels.CIG improves post-translational modification of tau as well as synaptic abnormalities.The data presented here reveal that CIG may be used in the treatment of AD.展开更多
rTg4510 mice are transgenic mice expressing P301L mutant tau and have been developed as an animal model of tauopathies including Alzheimer’s disease(AD).Besides cognitive impairments,rTg4510 mice also show abnormal h...rTg4510 mice are transgenic mice expressing P301L mutant tau and have been developed as an animal model of tauopathies including Alzheimer’s disease(AD).Besides cognitive impairments,rTg4510 mice also show abnormal hyperactivity behavior.Cornel iridoid glycoside(CIG)is an active ingredient extracted from Cornus officinalis,a traditional Chinese herb.The purpose of the present study was to investigate the effects of CIG on the emotional disorders such as hyperactivity,and related mechanisms.The emotional hyperactivity was detected by locomotor activity test and Y maze test.Immunofluorescent and immunohistochemical analyses were conducted to measure neuron loss and phosphorylated tau.Western blotting was used to detect the expression of related proteins.The results showed that intragastric administration of CIG for 3 months decreased the hyperactivity phenotype,prevented neuronal loss,reduced tau hyperphosphorylation and aggregation in the amygdala of rTg4510 mice.Meanwhile,CIG alleviated the synaptic dysfunction by increasing the expression of N-methyl-D-aspartate receptors(NMDARs)subunits GluN1 and GluN2A andαamino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor(AMPAR)subunits GluA1 and GluA2,and increased the level of phosphorylated Ca2+/calmodulin dependent protein kinase IIα(p-CaMK IIα)in the brain of rTg4510 mice.In conclusion,CIG may have potential to treat the emotional disorders in tauopathies such as AD through reducing tau pathology and improving synaptic dysfunction.展开更多
OBJECTIVE The aim of the present study was to investigate the effect of cornel iridoid glycoside(CIG)on tau hyperphosphorylation induced by wortmannin(WT)and GF-109203X(GFX)and the underlying mechanisms.METHODS Human ...OBJECTIVE The aim of the present study was to investigate the effect of cornel iridoid glycoside(CIG)on tau hyperphosphorylation induced by wortmannin(WT)and GF-109203X(GFX)and the underlying mechanisms.METHODS Human neuroblastoma SK-N-SH cells were pre-incubated with CIG(50,100,and 200μg·mL-1,respectively)for 24 h,and then exposed to WT 10μmol·L-1 and GFX 10μmol·L-1for 3hafter washing out CIG.Immuno-fluorescence was used to observe the microtubular cytoskeleton of the cultured cells.Western blotting was used to measure the phosphorylation level of tau protein,glycogen synthase kinase 3β(GSK-3β)and protein phosphatase 2A(PP2A).The activity of PP2 Awas detected by a biochemical assay.RESULTS Pre-incubation of CIG significantly attenuated the WT/GFX-induced tau hyperphosphorylation at the sites of Thr205,Thr212,Ser214,Thr217Ser396 and PHF-1,and improved the damage of morphology and microtubular cytoskeleton of the cells.CIG did not prevent the decrease in p-AKT-ser473 and pGSK3β-ser9 induced by WT/GFX.However,CIG significantly elevated the activity of PP2 Aby reducing the demethylation of PP2AC at Leu309 and the ratio of PME-1/LCMT in the WT/GFX-treated cells.CONCLUSION CIG obviously attenuated WT/GFX-induced tau hyper-phosphorylation at multiple AD-related sites by increasing the activity of PP2A.The mechanism may be involved in the reduced demethylation of PP2 Avia down regulating the ratio of PME/LCMT.展开更多
Ischemic stroke often elicits profound white matter lesions, which results in poor neurological outcomes and impairing the recovery in post-stroke. However, few studies have focused on white matter lesions caused by c...Ischemic stroke often elicits profound white matter lesions, which results in poor neurological outcomes and impairing the recovery in post-stroke. However, few studies have focused on white matter lesions caused by cerebral ischemia. The present study was aimed to investigate the effects of cornel iridoid glycoside(CIG), a main active component extracted from Cornus officinalis, on the white matter injury induced by ischemic stroke. CIG(60 and 120 mg·kg-1) were administered intragastrically 6 h after middle cerebral artery occlusion reperfusion(MCAO) surgery once a day for 7 d. A series of behavioral tests were carried out to evaluate the neurological function of MCAO rats. White matter structure was detected by luxol fast blue staining and transmission electron microscopy. Immunohistochemical staining was used to assess myelin loss, oligodendrocytes maturation and glial activation. Results showed that CIG remarkably decreased neurological deficit score, accelerated the recovery of somatosensory and motor functions, and ameliorated the memory deficit in MCAO rats. CIG alleviated white matter lesions and demyelination, increased myelin basic protein expression and the number of mature oligodendrocytes in the corpus callosum of MCAO rats. Besides, CIG inhibited the activation of microglia and astrocytes. Further data obtained by western blot analysis indicated that CIG increased the expression of brain-derived neurotrophic factor(BDNF)/p-Trk B, neuregulin-1/Erb B, and PI3 K p110α/p-Akt/p-m TOR in the corpus callosum of MCAO rats. Our findings demonstrated that CIG protected against white matter lesions induced by cerebral ischemia and the mechanisms were partially contributed to increasing BDNF and activating neuregulin-1/Erb B signaling and its downstream PI3 K/Akt/m TOR pathway in white matter.展开更多
OBJECTIVE PP2Ac demethyl⁃ation is regulated by LCMT(a specific leucine carboxyl methyltransferase catalyzing methyla⁃tion of PP2A)and PME(a specific methylester⁃ase catalyzing demethylation of PP2A.This study was to i...OBJECTIVE PP2Ac demethyl⁃ation is regulated by LCMT(a specific leucine carboxyl methyltransferase catalyzing methyla⁃tion of PP2A)and PME(a specific methylester⁃ase catalyzing demethylation of PP2A.This study was to investigate the mechanism of Cor⁃nel iridoid glycoside(CIG)on PP2A catalytic sub⁃unit C(PP2Ac).METHODS Recombined lentivi⁃rus vector was used to deliver PME-1 genetic materials into N2a cells or transfected LCMT-1 siRNA into N2a cells to block the expression of LCMT-1.Twenty-four hours later,cells were rinsed twice with cold PBS(pH 7.4)and CIG at different concentrations(50,100 and 200 g·L^(-1),respectively)were added for 24 h.Western blotting was used to PP2Ac,demethylaion/methylation PP2Ac,LCMT-1 and PME-1.The ac⁃tivity of PP2A was detected by a biochemical as⁃say.RESULTS①Lentivirus transferred PME-1 was expressed at high level in the N2a cells after transduction.Correspondingly,the demethylation of PP2Ac was increasing and PP2A activity was decreasing after transduction.Treatment with CIG for 24 h reversed the increase of PME-1 and demethylation of PP2Ac without influencing LCMT-1 expression.PP2A activity was also sig⁃nificantly enhanced in CIG treatment group,compared with the cells after PME-1 transduc⁃tion.②LCMT-1 siRNA significantly decreased LCMT-1 expression.CIG did not affect LCMT-1expression.however,demethylation of PP2Ac is increased in siRNA-transfected cells and CIG could reversed the high demethylation of PP2Ac and PP2A activity.CONLUSION CIG increases methylation of PP2A subunit C by inhibiting PME-1.展开更多
文摘Tau oligomers are the etiologic molecules of Alzheimer disease(AD), and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic aggregate species. The aim of the present study was to investigate the mechanisms of cornel iridoid glycoside(CIG) on tau oligomers and cognitive functions. We injected wortmannin and GF-109203 X(WM/GFX, 200 μmol·L-1 each) into the lateral ventricles to induce tau oligomer and memory impairment in rats. When oral y administered with CIG at 60 and 120 mg·kg-1 per day for 14 d, CIG decreased the escape latency in Morris water maze test. We also found that CIG restored the expression of presynaptic p-synapsin, synaptophysin, and postsynaptic density-95(PSD-95) decreased by WM/GFX in rat cortex. CIG reduced the accumulation of tau oligomers in the brain of WM/GFX rats and in cells transfected with wild type glycogen synthase kinase-3β(wt GSK-3β). In addition, CIG up-regulated the levels of ATG7, ATG12, Beclin-1, and LC3 II in vivo and in vitro, suggesting the restoration of autophagy function. These results suggest that CIG could ameliorate memory deficits and regulate memory-associated synaptic proteins through the clearance of tau oligomers accumulation. Moreover, CIG clears tau oligomers by restoring autophagy function.
基金This project was supported by grants from National Natural Science Foundation of China(No.81874351 and No 81703729)Beijing Hospitals Authority Ascent Plan of China(No.DFL20190803)National Major Science and Technology Projects of China(No.2015ZX09101-016).
文摘Alzheimer’s disease(AD),also defined as a tauopathology,is a common neurodegenerative disease.Hyper-phosphorylation,cleavage or truncation,and aggregation of tau contribute to AD.Thus,targeting the post-translational modifications on tau may be a therapeutic strategy to treat AD.This study understood how cornel iridoid glycoside(CIG)affects tau post-translational modifications and synaptic abnormalities.The 10-month old P301S tau transgenic mice were given CIG at 100 and 200 mg/kg every day orally for 1 month.Hyperphosphorylated and truncated tau,synapse-associated proteins and glutamatergic receptors were all detected using Western blotting.The interactions between Morroniside(MOR)or Loganin(LOG)and tau were detected using Autodock and Surface Plasmon Resonance(SPR).The effects of CIG on the aggregation of tau were investigated using a cell-free system.CIG attenuated tau hyperphosphorylation at Thr205,Ser212,Ser262,Thr231 and Ser235(AT180),but had no effect on tau truncation in the brains of 10-month old P301S mice.Binding free energies and interactions revealed that MOR and LOG bound with tau.We also found that CIG upregulated synapse-associated proteins such as PSD-95,syntaxin1A and synaptotagmin.In addition,CIG restored N-methyl-D-aspartic acid receptor and glutamate receptor levels.CIG improves post-translational modification of tau as well as synaptic abnormalities.The data presented here reveal that CIG may be used in the treatment of AD.
基金This research was supported by National Natural Science Foundation of China(Nos.81473373,81874351,81673406)Capital Science and Technology Leading Talent Training Project(No.Z 191100006119017)+1 种基金Beijing Hospitals Authority Ascent Plan(No.DFL20190803)Cultivation Fund of Capital Medical University(No.PYZ19134).
文摘rTg4510 mice are transgenic mice expressing P301L mutant tau and have been developed as an animal model of tauopathies including Alzheimer’s disease(AD).Besides cognitive impairments,rTg4510 mice also show abnormal hyperactivity behavior.Cornel iridoid glycoside(CIG)is an active ingredient extracted from Cornus officinalis,a traditional Chinese herb.The purpose of the present study was to investigate the effects of CIG on the emotional disorders such as hyperactivity,and related mechanisms.The emotional hyperactivity was detected by locomotor activity test and Y maze test.Immunofluorescent and immunohistochemical analyses were conducted to measure neuron loss and phosphorylated tau.Western blotting was used to detect the expression of related proteins.The results showed that intragastric administration of CIG for 3 months decreased the hyperactivity phenotype,prevented neuronal loss,reduced tau hyperphosphorylation and aggregation in the amygdala of rTg4510 mice.Meanwhile,CIG alleviated the synaptic dysfunction by increasing the expression of N-methyl-D-aspartate receptors(NMDARs)subunits GluN1 and GluN2A andαamino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor(AMPAR)subunits GluA1 and GluA2,and increased the level of phosphorylated Ca2+/calmodulin dependent protein kinase IIα(p-CaMK IIα)in the brain of rTg4510 mice.In conclusion,CIG may have potential to treat the emotional disorders in tauopathies such as AD through reducing tau pathology and improving synaptic dysfunction.
基金The project supported by National Natural Science Foundation of China(81274120,81273498)the Beijing Natural Science Foundation(7132110)+1 种基金the Beijing Science and Technology Program(Z131102002813066)the Capital Health Development Scientific Grant(2011-1001-05)
文摘OBJECTIVE The aim of the present study was to investigate the effect of cornel iridoid glycoside(CIG)on tau hyperphosphorylation induced by wortmannin(WT)and GF-109203X(GFX)and the underlying mechanisms.METHODS Human neuroblastoma SK-N-SH cells were pre-incubated with CIG(50,100,and 200μg·mL-1,respectively)for 24 h,and then exposed to WT 10μmol·L-1 and GFX 10μmol·L-1for 3hafter washing out CIG.Immuno-fluorescence was used to observe the microtubular cytoskeleton of the cultured cells.Western blotting was used to measure the phosphorylation level of tau protein,glycogen synthase kinase 3β(GSK-3β)and protein phosphatase 2A(PP2A).The activity of PP2 Awas detected by a biochemical assay.RESULTS Pre-incubation of CIG significantly attenuated the WT/GFX-induced tau hyperphosphorylation at the sites of Thr205,Thr212,Ser214,Thr217Ser396 and PHF-1,and improved the damage of morphology and microtubular cytoskeleton of the cells.CIG did not prevent the decrease in p-AKT-ser473 and pGSK3β-ser9 induced by WT/GFX.However,CIG significantly elevated the activity of PP2 Aby reducing the demethylation of PP2AC at Leu309 and the ratio of PME-1/LCMT in the WT/GFX-treated cells.CONCLUSION CIG obviously attenuated WT/GFX-induced tau hyper-phosphorylation at multiple AD-related sites by increasing the activity of PP2A.The mechanism may be involved in the reduced demethylation of PP2 Avia down regulating the ratio of PME/LCMT.
文摘Ischemic stroke often elicits profound white matter lesions, which results in poor neurological outcomes and impairing the recovery in post-stroke. However, few studies have focused on white matter lesions caused by cerebral ischemia. The present study was aimed to investigate the effects of cornel iridoid glycoside(CIG), a main active component extracted from Cornus officinalis, on the white matter injury induced by ischemic stroke. CIG(60 and 120 mg·kg-1) were administered intragastrically 6 h after middle cerebral artery occlusion reperfusion(MCAO) surgery once a day for 7 d. A series of behavioral tests were carried out to evaluate the neurological function of MCAO rats. White matter structure was detected by luxol fast blue staining and transmission electron microscopy. Immunohistochemical staining was used to assess myelin loss, oligodendrocytes maturation and glial activation. Results showed that CIG remarkably decreased neurological deficit score, accelerated the recovery of somatosensory and motor functions, and ameliorated the memory deficit in MCAO rats. CIG alleviated white matter lesions and demyelination, increased myelin basic protein expression and the number of mature oligodendrocytes in the corpus callosum of MCAO rats. Besides, CIG inhibited the activation of microglia and astrocytes. Further data obtained by western blot analysis indicated that CIG increased the expression of brain-derived neurotrophic factor(BDNF)/p-Trk B, neuregulin-1/Erb B, and PI3 K p110α/p-Akt/p-m TOR in the corpus callosum of MCAO rats. Our findings demonstrated that CIG protected against white matter lesions induced by cerebral ischemia and the mechanisms were partially contributed to increasing BDNF and activating neuregulin-1/Erb B signaling and its downstream PI3 K/Akt/m TOR pathway in white matter.
文摘OBJECTIVE PP2Ac demethyl⁃ation is regulated by LCMT(a specific leucine carboxyl methyltransferase catalyzing methyla⁃tion of PP2A)and PME(a specific methylester⁃ase catalyzing demethylation of PP2A.This study was to investigate the mechanism of Cor⁃nel iridoid glycoside(CIG)on PP2A catalytic sub⁃unit C(PP2Ac).METHODS Recombined lentivi⁃rus vector was used to deliver PME-1 genetic materials into N2a cells or transfected LCMT-1 siRNA into N2a cells to block the expression of LCMT-1.Twenty-four hours later,cells were rinsed twice with cold PBS(pH 7.4)and CIG at different concentrations(50,100 and 200 g·L^(-1),respectively)were added for 24 h.Western blotting was used to PP2Ac,demethylaion/methylation PP2Ac,LCMT-1 and PME-1.The ac⁃tivity of PP2A was detected by a biochemical as⁃say.RESULTS①Lentivirus transferred PME-1 was expressed at high level in the N2a cells after transduction.Correspondingly,the demethylation of PP2Ac was increasing and PP2A activity was decreasing after transduction.Treatment with CIG for 24 h reversed the increase of PME-1 and demethylation of PP2Ac without influencing LCMT-1 expression.PP2A activity was also sig⁃nificantly enhanced in CIG treatment group,compared with the cells after PME-1 transduc⁃tion.②LCMT-1 siRNA significantly decreased LCMT-1 expression.CIG did not affect LCMT-1expression.however,demethylation of PP2Ac is increased in siRNA-transfected cells and CIG could reversed the high demethylation of PP2Ac and PP2A activity.CONLUSION CIG increases methylation of PP2A subunit C by inhibiting PME-1.
