Background:Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease(AD).This study aimed to investigate whether and how the accumulating tau may in turn affect autop...Background:Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease(AD).This study aimed to investigate whether and how the accumulating tau may in turn affect autophagy.Methods:The primary hippocampal neurons,N2a and HEK293T cells with tau overexpression were respectively starved and treated with vinblastine to study the effects of tau on the initiating steps of autophagy,which was analysed by Student’s two-tailed t-test.The rapamycin and concanamycin A were employed to inhibit the mammalian target of rapamycin kinase complex 1(mTORC1)activity and the vacuolar H+-ATPase(v-ATPase)activity,respectively,which were analysed by One-way ANOVA with post hoc tests.The Western blotting,co-immunoprecipitation and immunofuorescence staining were conducted to gain insight into the mechanisms underlying the tau effects of mTORC1 signaling alterations,as analysed by Student’s two-tailed t-test or One-way ANOVA with post hoc tests.The autophagosome formation was detected by immunofuorescence staining and transmission electron microscopy.The amino acids(AA)levels were detected by high performance liquid chromatography(HPLC).Results:We observed that overexpressing human full-length wild-type tau to mimic AD-like tau accumulation induced autophagy deficits.Further studies revealed that the increased tau could bind to the prion-related domain of T cell intracellular antigen 1(PRD-TIA1)and this association significantly increased the intercellular level of amino acids(Leucine,P=0.0038;Glutamic acid,P=0.0348;Alanine,P=0.0037;Glycine,P=0.0104),with concordant upregulation of mTORC1 activity[phosphorylated eukaryotic translation initiation factor 4E-binding protein 1(p-4EBP1),P<0.0001;phosphorylated 70 kD ribosomal protein S6 kinase 1(p-p70S6K1),P=0.0001,phosphorylated unc-51-like autophagyactivating kinase 1(p-ULK1),P=0.0015]and inhibition of autophagosome formation[microtubuleassociated protein light chain 3 II(LC3 II),P=0.0073;LC3 puncta,P<0.0001].As expected,this tau-induced deficit of autophagosome formation in turn aggravated tau accumulation.Importantly,we also found that blocking TIA1 and tau interaction by overexpressing PRD-TIA1,downregulating the endogenous TIA1 expression by shRNA,or downregulating tau protein level by a small proteolysis targeting chimera(PROTAC)could remarkably attenuate tau-induced autophagy impairment.Conclusions:Our findings reveal that AD-like tau accumulation inhibits autophagosome formation and induces autophagy deficits by activating the TIA1/amino acid/mTORC1 pathway,and thus this work reveals new insight into tau-associated neurodegeneration and provides evidence supporting the use of new therapeutic targets for AD treat-ment and that of related tauopathies.展开更多
With the acceleration of population aging,the incidence of type 2 diabetes mellitus(T2DM)and Alzheimer’s disease(AD)is progressively increasing due to the age-relatedness of these two diseases.The association between...With the acceleration of population aging,the incidence of type 2 diabetes mellitus(T2DM)and Alzheimer’s disease(AD)is progressively increasing due to the age-relatedness of these two diseases.The association between T2DM and AD-like dementia is receiving much attention,and T2DM is reported to be a significant risk factor for AD.The aims of this review were to reveal the brain changes caused by T2DM as well as to explore the roles of hyperglycemia and insulin resistance in the development of AD.展开更多
According to the preliminary concept of the high-level radioactive waste （HLW） repository in China, a large-scale mock-up facility, named China-Mock-Up was constructed in the laboratory of Beijing Research Institute...According to the preliminary concept of the high-level radioactive waste （HLW） repository in China, a large-scale mock-up facility, named China-Mock-Up was constructed in the laboratory of Beijing Research Institute of Uranium Geology （BRIUG）. A heater, which simulates a container of radioactive waste, is placed inside the compacted Gaomiaozi （GMZ）-Na-bentonite blocks and pellets. Water inflow through the barrier from its outer surface is used to simulate the intake of groundwater. The numbers of water injection pipes, injection pressure and the insulation layer were determined based on the nu- merical modeling simulations. The current experimental data of the facility are herein analyzed. The experiment is intended to evaluate the thermo-hydro-mechano-chemical （THMC） processes occurring in the compacted bentonite-buffer during the early stage of HLW disposal and to provide a reliable database for numerical modeling and further investigation of engineered barrier system （EBS）, and the design of HLW repository.展开更多
The article“Protein Phosphatase 2A as a Drug Target in the Treatment of Cancer and Alzheimer's Disease”,written by Hui WEI,Hui-liang ZHANG,Jia-zhao XIE,Dong-li MENG,Xiao-chuan WANG,Dan KE,Ji ZENG,Rong LIU,was or...The article“Protein Phosphatase 2A as a Drug Target in the Treatment of Cancer and Alzheimer's Disease”,written by Hui WEI,Hui-liang ZHANG,Jia-zhao XIE,Dong-li MENG,Xiao-chuan WANG,Dan KE,Ji ZENG,Rong LIU,was originally published electronically on the publisher's internet portal on 13 March 2020 without open access.With the author(s)'decision to opt for Open Choice the copyright of the article changed to O The Author(s)2020 and the article is forthwith distributed under a Creative Commons Attribution 4.0 International License(https://creativecommons.org/licenses/by/4.0/),which permits use,sharing,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons license,and indicate if changes were made.展开更多
Background:Building brain reserves before dementia onset could represent a promising strategy to prevent Alzheimer’s disease(AD),while how to initiate early cognitive stimulation is unclear.Given that the immature br...Background:Building brain reserves before dementia onset could represent a promising strategy to prevent Alzheimer’s disease(AD),while how to initiate early cognitive stimulation is unclear.Given that the immature brain is more sensitive to environmental stimuli and that brain dynamics decrease with ageing,we reasoned that it would be effective to initiate cognitive stimulation against AD as early as the fetal period.Methods:After conception,maternal AD transgenic mice(3×Tg AD)were exposed to gestational environment enrichment(GEE)until the day of delivery.The cognitive capacity of the offspring was assessed by the Morris water maze and contextual fear-conditioning tests when the offspring were raised in a standard environment to 7 months of age.Western blotting,immunohistochemistry,real-time PCR,immunoprecipitation,chromatin immunoprecipitation(ChIP)assay,electrophysiology,Golgi staining,activity assays and sandwich ELISA were employed to gain insight into the mechanisms underlying the beneficial effects of GEE on embryos and 7–10-month-old adult offspring.Results:We found that GEE markedly preserved synaptic plasticity and memory capacity with amelioration of hallmark pathologies in 7–10-m-old AD offspring.The beneficial effects of GEE were accompanied by global histone hyperacetylation,including those at bdnf promoter-binding regions,with robust BDNF mRNA and protein expression in both embryo and progeny hippocampus.GEE increased insulin-like growth factor 1(IGF1)and activated its receptor(IGF1R),which phosphorylates Ca^(2+)/calmodulin-dependent kinase IV(CaMKIV)at tyrosine sites and triggers its nuclear translocation,subsequently upregulating histone acetyltransferase(HAT)and BDNF transcription.The upregulation of IGF1 mimicked the effects of GEE,while IGF1R or HAT inhibition during pregnancy abolished the GEE-induced CaMKIV-dependent histone hyperacetylation and BDNF upregulation.Conclusions:These findings suggest that activation of IGF1R/CaMKIV/HAT/BDNF signaling by gestational environment enrichment may serve as a promising strategy to delay AD progression.展开更多
Hyperphosphorylated tau is the major protein component of neurofibrillary tangles in the brains of patients with Alzheimer’s disease(AD). However, the mechanism underlying tau hyperphosphorylation is not fully unders...Hyperphosphorylated tau is the major protein component of neurofibrillary tangles in the brains of patients with Alzheimer’s disease(AD). However, the mechanism underlying tau hyperphosphorylation is not fully understood. Here, we demonstrated that exogenously expressed wild-type human tau40 was detectable in the phosphorylated form at multiple AD-associated sites in cytoplasmic and nuclear fractions from HEK293 cells.Among these sites, tau phosphorylated at Thr205 and Ser214 was almost exclusively found in the nuclear fraction at the conditions used in the present study. With the intracellular tau accumulation, the Ca2+concentration was significantly increased in both cytoplasmic and nuclear fractions. Further studies using site-specific mutagenesis and pharmacological treatment demonstrated that phosphorylation of tau at Thr205 increased nuclear Ca2+concentration with a simultaneous increase in the phosphorylation of Ca2+/calmodulin-dependent protein kinase IV(Ca MKIV) at Ser196. On the other hand, phosphorylation of tau at Ser214 did not significantly change the nuclear Ca2+/Ca MKIV signaling. Finally, expressing calmodulin-binding protein-4 that disrupts formation ofthe Ca2+/calmodulin complex abolished the okadaic acidinduced tau hyperphosphorylation in the nuclear fraction.We conclude that the intracellular accumulation of phosphorylated tau, as detected in the brains of AD patients, can trigger nuclear Ca2+/Ca MKIV signaling, which in turn aggravates tau hyperphosphorylation. Our findings provide new insights for tauopathies: hyperphosphorylation of intracellular tau and an increased Ca2+concentration may induce a self-perpetuating harmful loop to promote neurodegeneration.展开更多
基金supported by grants from the Natural Science Foundation of China(91949205,31730035,81721005)the Science and Technology Committee of China(2016YFC1305800)+1 种基金the Special Project of Technological Innovation of Hubei Province(2018ACA142)Guangdong Provincial Key S&T Program(2018B030336001)。
文摘Background:Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease(AD).This study aimed to investigate whether and how the accumulating tau may in turn affect autophagy.Methods:The primary hippocampal neurons,N2a and HEK293T cells with tau overexpression were respectively starved and treated with vinblastine to study the effects of tau on the initiating steps of autophagy,which was analysed by Student’s two-tailed t-test.The rapamycin and concanamycin A were employed to inhibit the mammalian target of rapamycin kinase complex 1(mTORC1)activity and the vacuolar H+-ATPase(v-ATPase)activity,respectively,which were analysed by One-way ANOVA with post hoc tests.The Western blotting,co-immunoprecipitation and immunofuorescence staining were conducted to gain insight into the mechanisms underlying the tau effects of mTORC1 signaling alterations,as analysed by Student’s two-tailed t-test or One-way ANOVA with post hoc tests.The autophagosome formation was detected by immunofuorescence staining and transmission electron microscopy.The amino acids(AA)levels were detected by high performance liquid chromatography(HPLC).Results:We observed that overexpressing human full-length wild-type tau to mimic AD-like tau accumulation induced autophagy deficits.Further studies revealed that the increased tau could bind to the prion-related domain of T cell intracellular antigen 1(PRD-TIA1)and this association significantly increased the intercellular level of amino acids(Leucine,P=0.0038;Glutamic acid,P=0.0348;Alanine,P=0.0037;Glycine,P=0.0104),with concordant upregulation of mTORC1 activity[phosphorylated eukaryotic translation initiation factor 4E-binding protein 1(p-4EBP1),P<0.0001;phosphorylated 70 kD ribosomal protein S6 kinase 1(p-p70S6K1),P=0.0001,phosphorylated unc-51-like autophagyactivating kinase 1(p-ULK1),P=0.0015]and inhibition of autophagosome formation[microtubuleassociated protein light chain 3 II(LC3 II),P=0.0073;LC3 puncta,P<0.0001].As expected,this tau-induced deficit of autophagosome formation in turn aggravated tau accumulation.Importantly,we also found that blocking TIA1 and tau interaction by overexpressing PRD-TIA1,downregulating the endogenous TIA1 expression by shRNA,or downregulating tau protein level by a small proteolysis targeting chimera(PROTAC)could remarkably attenuate tau-induced autophagy impairment.Conclusions:Our findings reveal that AD-like tau accumulation inhibits autophagosome formation and induces autophagy deficits by activating the TIA1/amino acid/mTORC1 pathway,and thus this work reveals new insight into tau-associated neurodegeneration and provides evidence supporting the use of new therapeutic targets for AD treat-ment and that of related tauopathies.
文摘With the acceleration of population aging,the incidence of type 2 diabetes mellitus(T2DM)and Alzheimer’s disease(AD)is progressively increasing due to the age-relatedness of these two diseases.The association between T2DM and AD-like dementia is receiving much attention,and T2DM is reported to be a significant risk factor for AD.The aims of this review were to reveal the brain changes caused by T2DM as well as to explore the roles of hyperglycemia and insulin resistance in the development of AD.
文摘According to the preliminary concept of the high-level radioactive waste （HLW） repository in China, a large-scale mock-up facility, named China-Mock-Up was constructed in the laboratory of Beijing Research Institute of Uranium Geology （BRIUG）. A heater, which simulates a container of radioactive waste, is placed inside the compacted Gaomiaozi （GMZ）-Na-bentonite blocks and pellets. Water inflow through the barrier from its outer surface is used to simulate the intake of groundwater. The numbers of water injection pipes, injection pressure and the insulation layer were determined based on the nu- merical modeling simulations. The current experimental data of the facility are herein analyzed. The experiment is intended to evaluate the thermo-hydro-mechano-chemical （THMC） processes occurring in the compacted bentonite-buffer during the early stage of HLW disposal and to provide a reliable database for numerical modeling and further investigation of engineered barrier system （EBS）, and the design of HLW repository.
文摘The article“Protein Phosphatase 2A as a Drug Target in the Treatment of Cancer and Alzheimer's Disease”,written by Hui WEI,Hui-liang ZHANG,Jia-zhao XIE,Dong-li MENG,Xiao-chuan WANG,Dan KE,Ji ZENG,Rong LIU,was originally published electronically on the publisher's internet portal on 13 March 2020 without open access.With the author(s)'decision to opt for Open Choice the copyright of the article changed to O The Author(s)2020 and the article is forthwith distributed under a Creative Commons Attribution 4.0 International License(https://creativecommons.org/licenses/by/4.0/),which permits use,sharing,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons license,and indicate if changes were made.
基金This work was supported in part by grants from the NSFC(91632305,91632111,31730035 and 81721005)by the Ministry of Science and Technology of China(2016YFC1305800).
文摘Background:Building brain reserves before dementia onset could represent a promising strategy to prevent Alzheimer’s disease(AD),while how to initiate early cognitive stimulation is unclear.Given that the immature brain is more sensitive to environmental stimuli and that brain dynamics decrease with ageing,we reasoned that it would be effective to initiate cognitive stimulation against AD as early as the fetal period.Methods:After conception,maternal AD transgenic mice(3×Tg AD)were exposed to gestational environment enrichment(GEE)until the day of delivery.The cognitive capacity of the offspring was assessed by the Morris water maze and contextual fear-conditioning tests when the offspring were raised in a standard environment to 7 months of age.Western blotting,immunohistochemistry,real-time PCR,immunoprecipitation,chromatin immunoprecipitation(ChIP)assay,electrophysiology,Golgi staining,activity assays and sandwich ELISA were employed to gain insight into the mechanisms underlying the beneficial effects of GEE on embryos and 7–10-month-old adult offspring.Results:We found that GEE markedly preserved synaptic plasticity and memory capacity with amelioration of hallmark pathologies in 7–10-m-old AD offspring.The beneficial effects of GEE were accompanied by global histone hyperacetylation,including those at bdnf promoter-binding regions,with robust BDNF mRNA and protein expression in both embryo and progeny hippocampus.GEE increased insulin-like growth factor 1(IGF1)and activated its receptor(IGF1R),which phosphorylates Ca^(2+)/calmodulin-dependent kinase IV(CaMKIV)at tyrosine sites and triggers its nuclear translocation,subsequently upregulating histone acetyltransferase(HAT)and BDNF transcription.The upregulation of IGF1 mimicked the effects of GEE,while IGF1R or HAT inhibition during pregnancy abolished the GEE-induced CaMKIV-dependent histone hyperacetylation and BDNF upregulation.Conclusions:These findings suggest that activation of IGF1R/CaMKIV/HAT/BDNF signaling by gestational environment enrichment may serve as a promising strategy to delay AD progression.
基金supported by the National Natural Science Foundation of China(91632305)the National Key Research and Development Program of China(2016YFC13058001)
文摘Hyperphosphorylated tau is the major protein component of neurofibrillary tangles in the brains of patients with Alzheimer’s disease(AD). However, the mechanism underlying tau hyperphosphorylation is not fully understood. Here, we demonstrated that exogenously expressed wild-type human tau40 was detectable in the phosphorylated form at multiple AD-associated sites in cytoplasmic and nuclear fractions from HEK293 cells.Among these sites, tau phosphorylated at Thr205 and Ser214 was almost exclusively found in the nuclear fraction at the conditions used in the present study. With the intracellular tau accumulation, the Ca2+concentration was significantly increased in both cytoplasmic and nuclear fractions. Further studies using site-specific mutagenesis and pharmacological treatment demonstrated that phosphorylation of tau at Thr205 increased nuclear Ca2+concentration with a simultaneous increase in the phosphorylation of Ca2+/calmodulin-dependent protein kinase IV(Ca MKIV) at Ser196. On the other hand, phosphorylation of tau at Ser214 did not significantly change the nuclear Ca2+/Ca MKIV signaling. Finally, expressing calmodulin-binding protein-4 that disrupts formation ofthe Ca2+/calmodulin complex abolished the okadaic acidinduced tau hyperphosphorylation in the nuclear fraction.We conclude that the intracellular accumulation of phosphorylated tau, as detected in the brains of AD patients, can trigger nuclear Ca2+/Ca MKIV signaling, which in turn aggravates tau hyperphosphorylation. Our findings provide new insights for tauopathies: hyperphosphorylation of intracellular tau and an increased Ca2+concentration may induce a self-perpetuating harmful loop to promote neurodegeneration.
