Alzheimer’s disease (AD) is the most prevalent cause of dementia worldwide. Because of the progressive neurodegeneration, individual cognitive and behavioral functions are impaired, affecting the quality of life of m...Alzheimer’s disease (AD) is the most prevalent cause of dementia worldwide. Because of the progressive neurodegeneration, individual cognitive and behavioral functions are impaired, affecting the quality of life of millions of people. Although the exact pathogenesis of AD has not been fully elucidated, amyloid plaques, neurofibrillary tangles (NFTs), and sustaining neuroinflammation dominate its characteristics. As one of the major tau kinases leading to hyperphosphorylation and aggregation of tau, glycogen synthase kinase-3β (GSK-3β) has been drawing great attention in various AD studies. Another research focus of AD in recent years is the inflammasome, a multiprotein complex acting as a regulator in immunological reactions to exogenous and endogenous danger signals, of which the Nod-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome has been studied mostly in AD and proven to play a significant role in AD development by its activation and downstream effects such as caspase-1 maturation and interleukin (IL)-1β release. Studies have shown that the NLRP3 inflammasome is activated in a GSK-3β-dependent way and that inhibition of the NLRP3 inflammasome downregulates GSK-3β, suggesting that these two important proteins are closely related. This article reviews the respective roles of GSK-3β and the NLRP3 inflammasome in AD as well as their relationship and interaction.展开更多
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
Interleukin-4(IL-4) has a protective effect against cerebral ischemia/reperfusion injury. Animal experiments have shown that IL-4 improves the short-and long-term prognosis of neurological function. The Akt(also calle...Interleukin-4(IL-4) has a protective effect against cerebral ischemia/reperfusion injury. Animal experiments have shown that IL-4 improves the short-and long-term prognosis of neurological function. The Akt(also called protein kinase B, PKB)/glycogen synthase kinase-3β(Akt/GSK-3β) signaling pathway is involved in oxidative stress, the inflammatory response, apoptosis, and autophagy. However, it is not yet clear whether the Akt/GSK-3β pathway participates in the neuroprotective effect of IL-4 against cerebral ischemia/reperfusion injury. In the present study, we established a cerebral ischemia/reperfusion mouse model by middle cerebral artery occlusion for 60 minutes followed by a 24-hour reperfusion. An IL-4/anti-IL-4 complex(10 μg) was intraperitoneally administered 30 minutes before surgery. We found that administration of IL-4 significantly alleviated the neurological deficits, oxidative stress, cell apoptosis, and autophagy and reduced infarct volume of the mice with cerebral ischemia/reperfusion injury 24 hours after reperfusion. Simultaneously, IL-4 activated Akt/GSK-3β signaling pathway. However, an Akt inhibitor LY294002, which was injected at 15 nmol/kg via the tail vein, attenuated the protective effects of IL-4. These findings indicate that IL-4 has a protective effect on cerebral ischemia/reperfusion injury by mitigating oxidative stress, reducing apoptosis, and inhibiting excessive autophagy, and that this mechanism may be related to activation of the Akt/GSK-3β pathway. This animal study was approved by the Animal Ethics Committee of Renmin Hospital of Wuhan University, China(approval No. WDRY2017-K037) on March 9, 2017.展开更多
The present study established global brain ischemia using the four-vessel occlusion method. Following three rounds of reperfusion for 30 seconds, and occlusion for 10 seconds, followed by reperfusion for 48 hours, inf...The present study established global brain ischemia using the four-vessel occlusion method. Following three rounds of reperfusion for 30 seconds, and occlusion for 10 seconds, followed by reperfusion for 48 hours, infarct area, the number of TUNEL-positive cells and Bcl-2 expression were significantly reduced. However, glycogen synthase kinase-3β activity, cortical Bax and caspase-3 expression significantly increased, similar to results following ischemic postconditioning. Our results indicated that ischemic postconditioning may enhance glycogen synthase kinase-3β activity, a downstream molecule of the phosphatase and tensin homolog deleted on chromosome 10/phosphatidylinositol 3-kinase/protein kinase B signaling pathway, which reduces caspase-3 expression to protect the brain against ischemic injury.展开更多
1-methyl-4-phenylpyridinium ion （MPP^＋） induces endoplasmic reticulum stress and activates caspase-12 in PC12 cells, leading to neuronal apoptosis. However, the underlying molecular mechanism remains unknown. The p...1-methyl-4-phenylpyridinium ion （MPP^＋） induces endoplasmic reticulum stress and activates caspase-12 in PC12 cells, leading to neuronal apoptosis. However, the underlying molecular mechanism remains unknown. The present study investigated the regulatory effects of nerve growth factor （Akt activator） and lithium chloride （glycogen synthase kinase-3β inhibitor） on the endoplasmic reticulum stress signaling pathway. The results revealed that MPP＋ induced expression of Bip and C/EBP homologous protein. The upregulation of Bip and C/EBP homologous protein, as well as the decreased pro-caspase-12 level induced by MPP^＋ were inhibited by pretreatment of the nerve growth factor or lithium chloride. These results suggest that the phosphatidylinositol 3 kinase-Aktglycogen synthase kinase-3β pathway is involved in MPP-induced endoplasmic reticulum stress.展开更多
Multiple roles of glycogen synthase kinase-3（GSK-3）in neural tissues：GSK-3 is a serine/threonine kinase that has two isoforms encoded by two different genes,GSK-3αand GSK-3β,in mammals.GSK-3 has several sites of ...Multiple roles of glycogen synthase kinase-3（GSK-3）in neural tissues：GSK-3 is a serine/threonine kinase that has two isoforms encoded by two different genes,GSK-3αand GSK-3β,in mammals.GSK-3 has several sites of serine and tyrosine phosphorylation.展开更多
Objective The mangrove tree Xylocarpus granatum J.Koenig(X.granatum)is a medicinal plant used to treat various diseases in several Asian countries.Many bioactive natural products have been isolated from the plants,par...Objective The mangrove tree Xylocarpus granatum J.Koenig(X.granatum)is a medicinal plant used to treat various diseases in several Asian countries.Many bioactive natural products have been isolated from the plants,particularly several groups of limonoids,including 18 xylogranatins(Xyl-A to R),all of which bear a furyl-δ-lactone core commonly found in limonoids.Based on a structural analogy with the limonoids obacunone and gedunin,we hypothesized that xylogranatins could target the enzyme glycogen synthase kinase-3β(GSK-3β),a major target for the treatment of neurodegenerative pathologies,viral infections,and cancers.Methods We investigated the binding of the 18 xylogranatins to GSK-3βusing molecular docking in comparison with two known reference GSK-3βATP-competitive inhibitors,LY2090314 and AR-A014418.For each compound bound to GSK-3β,the empirical energy of interaction(ΔE)was calculated and compared to that obtained with known GSK-3βinhibitors and limonoid triterpenes that target this enzyme.Results Five compounds were identified as potential GSK-3βbinders,Xyl-A,-C,-J,-N,and-O,for which the calculated empiricalΔE was equivalent to that calculated using the best reference molecule AR-A014418.The best ligand is Xyl-C,which is known to have marked anticancer properties.Binding of Xyl-C to the ATP-binding pocket of GSK-3βpositions the furyl-δ-lactone unit deep into the binding-site cavity.Other xylogranatin derivatives bearing a central pyridine ring or a compact polycyclic structure are much less adapted for GSK-3βbinding.Structure-binding relationships are discussed.Conclusion GSK-3βmay contribute to the anticancer effects of X.granatum extract.This study paves the way for the identification of other furyl-δ-lactone-containing limonoids as GSK-3βmodulators.展开更多
In this study, we studied the effect of glycogen synthase kinase-3 （GSK-3） overactivation on neurofilament phosphorylation in cultured cells. After N2a cells were treated with the specific inhibitor （wortmannin） o...In this study, we studied the effect of glycogen synthase kinase-3 （GSK-3） overactivation on neurofilament phosphorylation in cultured cells. After N2a cells were treated with the specific inhibitor （wortmannin） of phosphomosnol-3 kinase （PI-3K） or treated with wortmannin and the specific inhibitor （LiCl） of glycogen synthase kinase-3 （GSK-3）, GSK-3 activity and neurofilament phosphorylation were detected by using GSK-3 activity assay, Western blots and immunofluoresence. Our results showed that after treatment of N2a cells with wortmannin for 1 h, overactivation of GSK-3 caused a reduced staining with antibody SMI32 and an enhanced staining with antibody SMI31. When N2a cells were treated with wortmannin and LiCl, the activity of GSK-3 was reduced substantially. At the same time, the phosphorylation of neurofilament was also reduced. The study demonstrated that overactivation of GSK-3 induced hyperphosphorylation of neurofilament and suggested that in vitro overactivation of GSK-3 resulted in neurofilament hyperphosphorylation and this may be the underlying mechanism for Alzheimer＇s disease.展开更多
Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanism...Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanisms of GSK3βprotein expression remain elusive.Methods:Co-immunoprecipitation and mass spectral assays were performed to identify molecules binding to GSK3β,and to characterize the interactions of GSK3β,heat shock protein 90(Hsp90),and co-chaperones.The role of PGK1 in Hsp90 chaperoning GSK3βwas evaluated by constructing 293T cells stably expressing different domains/mutants of Hsp90α,and by performing a series of binding assays with bacterially purified proteins and clinical specimens.The influences of Hsp90 inhibitors on breast cancer stem cell stemness were investigated by Western blot and mammosphere formation assays.Results:We showed that GSK3βwas a client protein of Hsp90.Hsp90,which did not directly bind to GSK3β,interacted with phosphoglycerate kinase 1 via its C-terminal domain,thereby facilitating the binding of GSK3βto Hsp90.GSK3β-bound PGK1 interacted with Hsp90 in the“closed”conformation and stabilized GSK3βexpression in an Hsp90 activity-dependent manner.The Hsp90 inhibitor,17-AAG,rather than HDN-1,disrupted the interaction between Hsp90 and PGK1,and reduced GSK3βexpression,resulting in significantly reduced inhibition ofβ-catenin expression,to maintain the stemness of breast cancer stem cells.Conclusions:Our findings identified a novel regulatory mechanism of GSK3βexpression involving metabolic enzyme PGK1-coupled Hsp90,and highlighted the potential for more effective cancer treatment by selecting Hsp90 inhibitors that do not affect PGK1-regulated GSK3βexpression.展开更多
Inhibition ofβ-site amyloid precursor protein-cleaving enzyme 1(BACE1)or glycogen synthase kinase-3β(GSK-3β)is estimated to be the central therapeutic approach for Alzheimer’s disease(AD).In this study,water extra...Inhibition ofβ-site amyloid precursor protein-cleaving enzyme 1(BACE1)or glycogen synthase kinase-3β(GSK-3β)is estimated to be the central therapeutic approach for Alzheimer’s disease(AD).In this study,water extract of Kangenkaryu,its crude drug and chemical composition used in oriental medicine were evaluated regarding their BACE1 and GSK-3βinhibitory activities.Fluorescence resonance energy transfer was used to characterize the BACE1 inhibitory effect of Kangen-karyu,its crude drug and chemical composition.GSK-3βactivity was determined using the Kinase-Glo Luminescent Kinase Assay Platform.The water extract of Kangen-karyu inhibited BACE1 and GSK-3βin concentration-dependent manners when compared with reference drugs,quercetin and luteolin.Among six components of Kangen-karyu,the water extracts of Salviae Miltiorrhizae Radix or Cyperi Rhizoma exhibited significant inhibitory effects on BACE1 and GSK-3β.Among the constituents of Salviae Miltiorrhizae Radix extract,salvianolic acid C,salvianolic acid A,rosmarinic acid,and magnesium lithospermate B significantly inhibited BACE1.In addition,they inhibited GSK-3βwith an IC50 value range of 6.97 to 135.35μM.From these results,one of the effectiveness and its mechanisms of action of Kangen-karyu against AD may be the inhibition of BACE1 and GSK-3β,and one of the active ingredients of Kangen-karyu is Salviae Miltiorrhizae Radix and its constituents.展开更多
Background： Cognitive impairment is a severe complication caused by obstructive sleep apnea （OSA）. The mechanisms of causation are still unclear. The Wntβ-catenin signaling pathway is involved in cognition, and ab...Background： Cognitive impairment is a severe complication caused by obstructive sleep apnea （OSA）. The mechanisms of causation are still unclear. The Wntβ-catenin signaling pathway is involved in cognition, and abnormalities in it are implicated in neurological disorders. Here, we explored the Wntβ-catenin signaling pathway abnormalities caused by chronic intermittent hypoxia （CIH）, the most characteristic pathophysiological component of OSA. Methods： We divided 32 4-week-old male C57/BL mice into four groups of eight each： a CIH ＋ normal saline （NS） group, CIH ＋ LiCI group, sham CIH ＋ NS group, and a sham CIH ＋ LiCI group. The spatial learning performance of each group was assessed by using the Morris water maze （MWM）. Protein expressions of glycogen synthase kinase-β （GSK-β） and β-catenin in the hippocampus were examined using the Western blotting test. EdU labeling and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining methods were used, respectively, to determine the proliferation and apoptosis of neurons in the hippocampal dentate gyrus region. Results： Mice exposed to CIH showed impaired spatial learning performance in the MWM, including increased mean escape latencies to reach the target platform, decreased mean times passing through the target platform and mean duration in the target quadrant. The GSK-313 activity increased, and expression of β-catenin decreased significantly in the hippocampus of the CIH-exposed mice. Besides, CIH significantly increased hippocampal neuronal apoptosis, with an elevated apoptosis index. Meanwhile, LiCI decreased the activity of GSK-β and increased the expression of β-catenin and partially reversed the spatial memory deficits in MWM and the apoptosis caused by CIH. Conclusions： Wntβ-catenin signaling pathway abnormalities possibly play an important role in the development of cognitive deficits among mice exposed to CIH and that LiCI might attenuate CIH-induced cognitive impairment via Wntβ-catenin signaling pathway.展开更多
Background Diabetes-related pathogenic factors can cause retinal ganglion cell （RGC） apoptosis, but the specific mechanism is not very clear. The aim of this study is to investigate the correlation between glycogen ...Background Diabetes-related pathogenic factors can cause retinal ganglion cell （RGC） apoptosis, but the specific mechanism is not very clear. The aim of this study is to investigate the correlation between glycogen synthase kinase-3 （GSK-3） activation and retinal neuron apoptosis. Methods In an in vitro experiment, the number of apoptotic RGC-5 cells differentiated by staurosporine was evaluated via flow cytometry and nuclei staining using Hoechst 33258. GSK-3 phosphorylation and caspase-3 activation in RGC-5 cells after serum deprivation were determined using Western blotting. Mitochondrial membrane potential was detected using the dye 5,5＇,6,6＇-tetrachloro-l,l＇,3,3＇-tetrethyl benzimidalyl carbocyanine iodide, and reactive oxygen species （ROS） levels were measured with dihydroethidium. In an in vivo experiment, the number of apoptotic retinal neurons was evaluated via terminal transferase dUTP nick-end labeling （TUNEL）, and GSK-3 phosphorylation was determined using Western blotting, in the retinal nerve epithelial tissue of rats in which diabetes was induced by intravenous tail-vein injection of streptozotocin for 4 weeks. Results The levels of phosphorylated Ser21/9 in GSK-3α/13 and p-T308/S473-AKT were lower and the cleaved caspase-3 levels were higher in the serum-deprived model （P 〈0.05）. Lithium chloride treatment was associated with a slower rate of apoptosis, increased mitochondrial membrane potential, and decreased ROS levels in differentiated RGC-5 cells （P 〈0.05）. The level of blood glucose and the number of TUNEL-positive cells in the whole-mounted retinas were higher （P 〈0.01）, and the levels of phosphorylated Ser21/9 in GSK-3α/13 and body weight were lower （P 〈0.05）. However, the thickness of the retinal nerve epithelial layer was not significantly less in diabetic rats compared with control group. Lithium chloride intravitreal injection increased the levels of phosphorylated Ser21/9 in GSK-3α/13 and decreased TUNEL-positive cells in the whole-mounted retinas. Conclusion GSK-3 kinase is closely related to retinal neuron apoptosis, and the application of the GSK-3 inhibitor lithium chloride can reduce retinal neuron apoptosis in early diabetic retinopathy.展开更多
A three dimensional pharmacophore model has been generated for glycogen synthase kinase-3 （GSK-3） inhibitots. A dataset consisting of 89 compounds was selected on the basis of the information content of the structur...A three dimensional pharmacophore model has been generated for glycogen synthase kinase-3 （GSK-3） inhibitots. A dataset consisting of 89 compounds was selected on the basis of the information content of the structures and activity data as required by the CATALYST system. The optimum model with four features （one hydrogen-bond acceptor unit, one ring aromatic unit, and two hydrophobic aromatic units） was selected with a good correlation coefficient （0.95）. This model is able to predict the activity of other known GSK-3 inhibitors not included in the model generation, and can be further used to identify structurally diverse compounds with desired biological activity by virtual screening.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.92049107 and No.31929002)the Innovative Research Groups of the National Natural Science Foundation of China(No.81721005)the Academic Frontier Youth Team Project to Xiaochuan Wang from Huazhong University of Science and Technology.
文摘Alzheimer’s disease (AD) is the most prevalent cause of dementia worldwide. Because of the progressive neurodegeneration, individual cognitive and behavioral functions are impaired, affecting the quality of life of millions of people. Although the exact pathogenesis of AD has not been fully elucidated, amyloid plaques, neurofibrillary tangles (NFTs), and sustaining neuroinflammation dominate its characteristics. As one of the major tau kinases leading to hyperphosphorylation and aggregation of tau, glycogen synthase kinase-3β (GSK-3β) has been drawing great attention in various AD studies. Another research focus of AD in recent years is the inflammasome, a multiprotein complex acting as a regulator in immunological reactions to exogenous and endogenous danger signals, of which the Nod-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome has been studied mostly in AD and proven to play a significant role in AD development by its activation and downstream effects such as caspase-1 maturation and interleukin (IL)-1β release. Studies have shown that the NLRP3 inflammasome is activated in a GSK-3β-dependent way and that inhibition of the NLRP3 inflammasome downregulates GSK-3β, suggesting that these two important proteins are closely related. This article reviews the respective roles of GSK-3β and the NLRP3 inflammasome in AD as well as their relationship and interaction.
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supported by the National Natural Science Foundation of China,Nos.81901994(to BZ)and 81571147(to XXX)the Natural Science Foundation of Hubei Province,China,No.2019CFC847(to WWG)the Fundamental Research Funds for the Central Universities,China,No.2042018kf0149(to ML)
文摘Interleukin-4(IL-4) has a protective effect against cerebral ischemia/reperfusion injury. Animal experiments have shown that IL-4 improves the short-and long-term prognosis of neurological function. The Akt(also called protein kinase B, PKB)/glycogen synthase kinase-3β(Akt/GSK-3β) signaling pathway is involved in oxidative stress, the inflammatory response, apoptosis, and autophagy. However, it is not yet clear whether the Akt/GSK-3β pathway participates in the neuroprotective effect of IL-4 against cerebral ischemia/reperfusion injury. In the present study, we established a cerebral ischemia/reperfusion mouse model by middle cerebral artery occlusion for 60 minutes followed by a 24-hour reperfusion. An IL-4/anti-IL-4 complex(10 μg) was intraperitoneally administered 30 minutes before surgery. We found that administration of IL-4 significantly alleviated the neurological deficits, oxidative stress, cell apoptosis, and autophagy and reduced infarct volume of the mice with cerebral ischemia/reperfusion injury 24 hours after reperfusion. Simultaneously, IL-4 activated Akt/GSK-3β signaling pathway. However, an Akt inhibitor LY294002, which was injected at 15 nmol/kg via the tail vein, attenuated the protective effects of IL-4. These findings indicate that IL-4 has a protective effect on cerebral ischemia/reperfusion injury by mitigating oxidative stress, reducing apoptosis, and inhibiting excessive autophagy, and that this mechanism may be related to activation of the Akt/GSK-3β pathway. This animal study was approved by the Animal Ethics Committee of Renmin Hospital of Wuhan University, China(approval No. WDRY2017-K037) on March 9, 2017.
基金sponsored by the National Natural Science Foundation of China,No.81170768
文摘The present study established global brain ischemia using the four-vessel occlusion method. Following three rounds of reperfusion for 30 seconds, and occlusion for 10 seconds, followed by reperfusion for 48 hours, infarct area, the number of TUNEL-positive cells and Bcl-2 expression were significantly reduced. However, glycogen synthase kinase-3β activity, cortical Bax and caspase-3 expression significantly increased, similar to results following ischemic postconditioning. Our results indicated that ischemic postconditioning may enhance glycogen synthase kinase-3β activity, a downstream molecule of the phosphatase and tensin homolog deleted on chromosome 10/phosphatidylinositol 3-kinase/protein kinase B signaling pathway, which reduces caspase-3 expression to protect the brain against ischemic injury.
基金the National Natural Science Foundation of China, No. 30860085a grant from the Candidates of Young and Middle-Aged Academic Leaders of Yunnan Province, No. 2006PY01-07the Natural Science Foundation of Yunnan Province, No. 2007C177M
文摘1-methyl-4-phenylpyridinium ion （MPP^＋） induces endoplasmic reticulum stress and activates caspase-12 in PC12 cells, leading to neuronal apoptosis. However, the underlying molecular mechanism remains unknown. The present study investigated the regulatory effects of nerve growth factor （Akt activator） and lithium chloride （glycogen synthase kinase-3β inhibitor） on the endoplasmic reticulum stress signaling pathway. The results revealed that MPP＋ induced expression of Bip and C/EBP homologous protein. The upregulation of Bip and C/EBP homologous protein, as well as the decreased pro-caspase-12 level induced by MPP^＋ were inhibited by pretreatment of the nerve growth factor or lithium chloride. These results suggest that the phosphatidylinositol 3 kinase-Aktglycogen synthase kinase-3β pathway is involved in MPP-induced endoplasmic reticulum stress.
文摘Multiple roles of glycogen synthase kinase-3（GSK-3）in neural tissues：GSK-3 is a serine/threonine kinase that has two isoforms encoded by two different genes,GSK-3αand GSK-3β,in mammals.GSK-3 has several sites of serine and tyrosine phosphorylation.
文摘Objective The mangrove tree Xylocarpus granatum J.Koenig(X.granatum)is a medicinal plant used to treat various diseases in several Asian countries.Many bioactive natural products have been isolated from the plants,particularly several groups of limonoids,including 18 xylogranatins(Xyl-A to R),all of which bear a furyl-δ-lactone core commonly found in limonoids.Based on a structural analogy with the limonoids obacunone and gedunin,we hypothesized that xylogranatins could target the enzyme glycogen synthase kinase-3β(GSK-3β),a major target for the treatment of neurodegenerative pathologies,viral infections,and cancers.Methods We investigated the binding of the 18 xylogranatins to GSK-3βusing molecular docking in comparison with two known reference GSK-3βATP-competitive inhibitors,LY2090314 and AR-A014418.For each compound bound to GSK-3β,the empirical energy of interaction(ΔE)was calculated and compared to that obtained with known GSK-3βinhibitors and limonoid triterpenes that target this enzyme.Results Five compounds were identified as potential GSK-3βbinders,Xyl-A,-C,-J,-N,and-O,for which the calculated empiricalΔE was equivalent to that calculated using the best reference molecule AR-A014418.The best ligand is Xyl-C,which is known to have marked anticancer properties.Binding of Xyl-C to the ATP-binding pocket of GSK-3βpositions the furyl-δ-lactone unit deep into the binding-site cavity.Other xylogranatin derivatives bearing a central pyridine ring or a compact polycyclic structure are much less adapted for GSK-3βbinding.Structure-binding relationships are discussed.Conclusion GSK-3βmay contribute to the anticancer effects of X.granatum extract.This study paves the way for the identification of other furyl-δ-lactone-containing limonoids as GSK-3βmodulators.
文摘In this study, we studied the effect of glycogen synthase kinase-3 （GSK-3） overactivation on neurofilament phosphorylation in cultured cells. After N2a cells were treated with the specific inhibitor （wortmannin） of phosphomosnol-3 kinase （PI-3K） or treated with wortmannin and the specific inhibitor （LiCl） of glycogen synthase kinase-3 （GSK-3）, GSK-3 activity and neurofilament phosphorylation were detected by using GSK-3 activity assay, Western blots and immunofluoresence. Our results showed that after treatment of N2a cells with wortmannin for 1 h, overactivation of GSK-3 caused a reduced staining with antibody SMI32 and an enhanced staining with antibody SMI31. When N2a cells were treated with wortmannin and LiCl, the activity of GSK-3 was reduced substantially. At the same time, the phosphorylation of neurofilament was also reduced. The study demonstrated that overactivation of GSK-3 induced hyperphosphorylation of neurofilament and suggested that in vitro overactivation of GSK-3 resulted in neurofilament hyperphosphorylation and this may be the underlying mechanism for Alzheimer＇s disease.
基金This work was supported by grants from the NSFC Shandong Joint Fund(Grant No.U1606403)the National Natural Science Foundation of China(Grant No.81673450)+4 种基金the State Key Program of the National Natural Science Foundation of China(Grant No.82030074)the NSFC-Shandong Joint Fund(Grant No.U1906212)the Qingdao National Laboratory for Marine Science and Technology(Grant No.2015ASKJ02)the National Science and Technology Major Project for Significant New Drugs Development(Grant No.2018ZX09735-004)the Shandong Provincial Natural Science Foundation(major basic research projects,Grant No.ZR2019ZD18).
文摘Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanisms of GSK3βprotein expression remain elusive.Methods:Co-immunoprecipitation and mass spectral assays were performed to identify molecules binding to GSK3β,and to characterize the interactions of GSK3β,heat shock protein 90(Hsp90),and co-chaperones.The role of PGK1 in Hsp90 chaperoning GSK3βwas evaluated by constructing 293T cells stably expressing different domains/mutants of Hsp90α,and by performing a series of binding assays with bacterially purified proteins and clinical specimens.The influences of Hsp90 inhibitors on breast cancer stem cell stemness were investigated by Western blot and mammosphere formation assays.Results:We showed that GSK3βwas a client protein of Hsp90.Hsp90,which did not directly bind to GSK3β,interacted with phosphoglycerate kinase 1 via its C-terminal domain,thereby facilitating the binding of GSK3βto Hsp90.GSK3β-bound PGK1 interacted with Hsp90 in the“closed”conformation and stabilized GSK3βexpression in an Hsp90 activity-dependent manner.The Hsp90 inhibitor,17-AAG,rather than HDN-1,disrupted the interaction between Hsp90 and PGK1,and reduced GSK3βexpression,resulting in significantly reduced inhibition ofβ-catenin expression,to maintain the stemness of breast cancer stem cells.Conclusions:Our findings identified a novel regulatory mechanism of GSK3βexpression involving metabolic enzyme PGK1-coupled Hsp90,and highlighted the potential for more effective cancer treatment by selecting Hsp90 inhibitors that do not affect PGK1-regulated GSK3βexpression.
文摘Inhibition ofβ-site amyloid precursor protein-cleaving enzyme 1(BACE1)or glycogen synthase kinase-3β(GSK-3β)is estimated to be the central therapeutic approach for Alzheimer’s disease(AD).In this study,water extract of Kangenkaryu,its crude drug and chemical composition used in oriental medicine were evaluated regarding their BACE1 and GSK-3βinhibitory activities.Fluorescence resonance energy transfer was used to characterize the BACE1 inhibitory effect of Kangen-karyu,its crude drug and chemical composition.GSK-3βactivity was determined using the Kinase-Glo Luminescent Kinase Assay Platform.The water extract of Kangen-karyu inhibited BACE1 and GSK-3βin concentration-dependent manners when compared with reference drugs,quercetin and luteolin.Among six components of Kangen-karyu,the water extracts of Salviae Miltiorrhizae Radix or Cyperi Rhizoma exhibited significant inhibitory effects on BACE1 and GSK-3β.Among the constituents of Salviae Miltiorrhizae Radix extract,salvianolic acid C,salvianolic acid A,rosmarinic acid,and magnesium lithospermate B significantly inhibited BACE1.In addition,they inhibited GSK-3βwith an IC50 value range of 6.97 to 135.35μM.From these results,one of the effectiveness and its mechanisms of action of Kangen-karyu against AD may be the inhibition of BACE1 and GSK-3β,and one of the active ingredients of Kangen-karyu is Salviae Miltiorrhizae Radix and its constituents.
基金This work was supported by a grant from the National Natural Science Foundation of China （No. 81370185）.
文摘Background： Cognitive impairment is a severe complication caused by obstructive sleep apnea （OSA）. The mechanisms of causation are still unclear. The Wntβ-catenin signaling pathway is involved in cognition, and abnormalities in it are implicated in neurological disorders. Here, we explored the Wntβ-catenin signaling pathway abnormalities caused by chronic intermittent hypoxia （CIH）, the most characteristic pathophysiological component of OSA. Methods： We divided 32 4-week-old male C57/BL mice into four groups of eight each： a CIH ＋ normal saline （NS） group, CIH ＋ LiCI group, sham CIH ＋ NS group, and a sham CIH ＋ LiCI group. The spatial learning performance of each group was assessed by using the Morris water maze （MWM）. Protein expressions of glycogen synthase kinase-β （GSK-β） and β-catenin in the hippocampus were examined using the Western blotting test. EdU labeling and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining methods were used, respectively, to determine the proliferation and apoptosis of neurons in the hippocampal dentate gyrus region. Results： Mice exposed to CIH showed impaired spatial learning performance in the MWM, including increased mean escape latencies to reach the target platform, decreased mean times passing through the target platform and mean duration in the target quadrant. The GSK-313 activity increased, and expression of β-catenin decreased significantly in the hippocampus of the CIH-exposed mice. Besides, CIH significantly increased hippocampal neuronal apoptosis, with an elevated apoptosis index. Meanwhile, LiCI decreased the activity of GSK-β and increased the expression of β-catenin and partially reversed the spatial memory deficits in MWM and the apoptosis caused by CIH. Conclusions： Wntβ-catenin signaling pathway abnormalities possibly play an important role in the development of cognitive deficits among mice exposed to CIH and that LiCI might attenuate CIH-induced cognitive impairment via Wntβ-catenin signaling pathway.
基金This study was supported by a grant from the National Nature Science Foundation of China （No. 81170863）.
文摘Background Diabetes-related pathogenic factors can cause retinal ganglion cell （RGC） apoptosis, but the specific mechanism is not very clear. The aim of this study is to investigate the correlation between glycogen synthase kinase-3 （GSK-3） activation and retinal neuron apoptosis. Methods In an in vitro experiment, the number of apoptotic RGC-5 cells differentiated by staurosporine was evaluated via flow cytometry and nuclei staining using Hoechst 33258. GSK-3 phosphorylation and caspase-3 activation in RGC-5 cells after serum deprivation were determined using Western blotting. Mitochondrial membrane potential was detected using the dye 5,5＇,6,6＇-tetrachloro-l,l＇,3,3＇-tetrethyl benzimidalyl carbocyanine iodide, and reactive oxygen species （ROS） levels were measured with dihydroethidium. In an in vivo experiment, the number of apoptotic retinal neurons was evaluated via terminal transferase dUTP nick-end labeling （TUNEL）, and GSK-3 phosphorylation was determined using Western blotting, in the retinal nerve epithelial tissue of rats in which diabetes was induced by intravenous tail-vein injection of streptozotocin for 4 weeks. Results The levels of phosphorylated Ser21/9 in GSK-3α/13 and p-T308/S473-AKT were lower and the cleaved caspase-3 levels were higher in the serum-deprived model （P 〈0.05）. Lithium chloride treatment was associated with a slower rate of apoptosis, increased mitochondrial membrane potential, and decreased ROS levels in differentiated RGC-5 cells （P 〈0.05）. The level of blood glucose and the number of TUNEL-positive cells in the whole-mounted retinas were higher （P 〈0.01）, and the levels of phosphorylated Ser21/9 in GSK-3α/13 and body weight were lower （P 〈0.05）. However, the thickness of the retinal nerve epithelial layer was not significantly less in diabetic rats compared with control group. Lithium chloride intravitreal injection increased the levels of phosphorylated Ser21/9 in GSK-3α/13 and decreased TUNEL-positive cells in the whole-mounted retinas. Conclusion GSK-3 kinase is closely related to retinal neuron apoptosis, and the application of the GSK-3 inhibitor lithium chloride can reduce retinal neuron apoptosis in early diabetic retinopathy.
文摘A three dimensional pharmacophore model has been generated for glycogen synthase kinase-3 （GSK-3） inhibitots. A dataset consisting of 89 compounds was selected on the basis of the information content of the structures and activity data as required by the CATALYST system. The optimum model with four features （one hydrogen-bond acceptor unit, one ring aromatic unit, and two hydrophobic aromatic units） was selected with a good correlation coefficient （0.95）. This model is able to predict the activity of other known GSK-3 inhibitors not included in the model generation, and can be further used to identify structurally diverse compounds with desired biological activity by virtual screening.
