Oxidative stress plays a significant role in the pathogenesis of Alzheimer＇s disease （AD）, a devastating disease of the elderly. The brain is more vulnerable than other organs to oxidative stress, and most of the c...Oxidative stress plays a significant role in the pathogenesis of Alzheimer＇s disease （AD）, a devastating disease of the elderly. The brain is more vulnerable than other organs to oxidative stress, and most of the components of neurons （lipids, proteins, and nucleic acids） can be oxidized in AD due to mitochondrial dysfunction, increased metal levels, inflammation, and β-amyloid （Aβ） peptides. Oxidative stress participates in the development of AD by promoting Aβ deposition, tau hyperphosphorylation, and the subsequent loss of synapses and neurons. The relationship between oxidative stress and AD suggests that oxidative stress is an essential part of the pathological process, and antioxidants may be useful for AD treatment.展开更多
Alzheimer’s disease(AD), the most common type of dementia, is becoming a major challenge for global health and social care. However, the current understanding of AD pathogenesis is limited, and no early diagnosis and...Alzheimer’s disease(AD), the most common type of dementia, is becoming a major challenge for global health and social care. However, the current understanding of AD pathogenesis is limited, and no early diagnosis and disease-modifying therapy are currently available. During the past year, significant progress has been made in clinical research on the diagnosis, prevention, and treatment of AD.In this review, we summarize the latest achievements,including diagnostic biomarkers, polygenic hazard score,amyloid and tau PET imaging, clinical trials targeting amyloid-beta(Ab), tau, and neurotransmitters, early intervention, and primary prevention and systemic intervention approaches, and provide novel perspectives for further efforts to understand and cure the disease.展开更多
Objective：To review recent research advances on tau,a major player in Alzheimer＇s disease （AD） pathogenesis,a biomarker for AD onset,and potential target for AD therapy.Data Sources：This review was based on a com...Objective：To review recent research advances on tau,a major player in Alzheimer＇s disease （AD） pathogenesis,a biomarker for AD onset,and potential target for AD therapy.Data Sources：This review was based on a comprehensive search using online literature databases,including PubMed,Web of Science,and Google Scholar.Study Selection：Literature search was based on the following keywords：Alzheimer＇s disease,tau protein,biomarker,cerebrospinal fluid （CSF）,therapeutics,plasma,imaging,propagation,spreading,seeding,prion,conformational templating,and posttranslational modification.Relevant articles were carefully reviewed,with no exclusions applied to study design and publication type.Results：Amyloid plaques enriched with extracellular amyloid beta （Aβ） and intracellular neurofibrillary tangles comprised of hyperphosphorylated tau proteins are the two main pathological hallmarks ofAD.Although the Aβ hypothesis has dominated AD research for many years,clinical Aβ-targeting strategies have consistently failed to effectively treat AD or prevent AD onset.The research focus in AD has recently shifted to the role oftau in AD.In addition to phosphorylation,tau is acetylated and proteolytically cleaved,which also contribute to its physiological and pathological functions.Emerging evidence characterizing pathological tau propagation and spreading provides new avenues for research into the molecular and cellular mechanisms underlying AD pathogenesis.Techniques to detect tau at minute levels in CSF and blood have been developed,and improved tracers have facilitated tau imaging in the brain.These advances have potential to accurately determine tau levels at early diagnostic stages in AD.Given that tau is a potential therapeutic target,anti-tau immunotherapy may potentially be a viable treatment strategy in AD intervention.Conclusion：Detecting changes in tau and targeting tau pathology represent a promising lead in the diagnosis and treatment of AD.展开更多
Alzheimer’s disease is characterized by the extracellular accumulation of the amyloidβin the form of amyloid plaques and the intracellular deposition of the microtubule-associated protein tau in the form of neurofib...Alzheimer’s disease is characterized by the extracellular accumulation of the amyloidβin the form of amyloid plaques and the intracellular deposition of the microtubule-associated protein tau in the form of neurofibrillary tangles.Most of the Alzheimer’s drugs targeting amyloidβhave been failed in clinical trials.Particularly,tau pathology connects greatly in the pathogenesis of Alzheimer’s disease.Tau protein enhances the stabilization of microtubules that leads to the appropriate function of the neuron.Changes in the quantity or the conformation of tau protein could affect its function as a microtubules stabilizer and some of the processes wherein it is involved.The molecular mechanisms leading to the accumulation of tau are principally signified by numerous posttranslational modifications that change its conformation and structural state.Therefore,aberrant phosphorylation,as well as truncation of tau protein,has come into focus as significant mechanisms that make tau protein in a pathological entity.Furthermore,the shape-shifting nature of tau advocates to comprehend the progression of Alzheimer’s disease precisely.In this review,we emphasize the recent studies about the toxic and shape-shifting nature of tau in the pathogenesis of Alzheimer’s disease.展开更多
Although hypothermia therapy is effective to treat neonatal hypoxic-ischemic encephalopathy,many neonatal patients die or suffer from severe neurological dysfunction.Erythropoietin is considered one of the most promis...Although hypothermia therapy is effective to treat neonatal hypoxic-ischemic encephalopathy,many neonatal patients die or suffer from severe neurological dysfunction.Erythropoietin is considered one of the most promising neuroprotective agents.We hypothesized that erythropoietin combined with hypothermia will improve efficacy of neonatal hypoxic-ischemic encephalopathy treatment.In this study,41 neonates with moderate/severe hypoxic-ischemic encephalopathy were randomly divided into a control group（hypothermia alone for 72 hours,n = 20） and erythropoietin group（hypothermia ＋ erythropoietin 200 IU/kg for 10 days,n = 21）.Our results show that compared with the control group,serum tau protein levels were lower and neonatal behavioral neurological assessment scores higher in the erythropoietin group at 8 and 12 days.However,neurodevelopmental outcome was similar between the two groups at 9 months of age.These findings suggest that erythropoietin combined with hypothermia reduces serum tau protein levels and improves neonatal behavioral neurology outcome but does not affect long-term neurodevelopmental outcome.展开更多
Alzheimer＇s disease（AD） is the most common form of dementia in the older population, however, the precise cause of the disease is unknown. The neuropathology is characterized by the presence of aggregates formed by...Alzheimer＇s disease（AD） is the most common form of dementia in the older population, however, the precise cause of the disease is unknown. The neuropathology is characterized by the presence of aggregates formed by amyloid-β（Aβ） peptide and phosphorylated tau; which is accompanied by progressive impairment of memory. Diverse signaling pathways are linked to AD, and among these the Wnt signaling pathway is becoming increasingly relevant, since it plays essential roles in the adult brain. Initially, Wnt signaling activation was proposed as a neuroprotective mechanism against Aβ toxicity. Later, it was reported that it participates in tau phosphorylation and processes of learning and memory. Interestingly, in the last years we demonstrated that Wnt signaling is fundamental in amyloid precursor protein（APP） processing and that Wnt dysfunction results in Aβ production and aggregation in vitro. Recent in vivo studies reported that loss of canonical Wnt signaling exacerbates amyloid deposition in a transgenic（Tg） mouse model of AD. Finally, we showed that inhibition of Wnt signaling in a Tg mouse previously at the appearance of AD signs, resulted in memory loss, tau phosphorylation and Aβ formation and aggregation; indicating that Wnt dysfunction accelerated the onset of AD. More importantly, Wnt signaling loss promoted cognitive impairment, tau phosphorylation and Aβ1–42 production in the hippocampus of wild-type（WT） mice, contributing to the development of an Alzheimer＇s-like neurophatology. Therefore, in this review we highlight the importance of Wnt/β-catenin signaling dysfunction in the onset of AD and propose that the loss of canonical Wnt signaling is a triggering factor of AD.展开更多
Synaptic abnormalities are a cardinal feature of Alzheimer’s disease(AD)that are known to arise as the disease progresses.A growing body of evidence suggests that pathological alterations to neuronal circuits and syn...Synaptic abnormalities are a cardinal feature of Alzheimer’s disease(AD)that are known to arise as the disease progresses.A growing body of evidence suggests that pathological alterations to neuronal circuits and synapses may provide a mechanistic link between amyloidβ(Aβ)and tau pathology and thus may serve as an obligatory relay of the cognitive impairment in AD.Brain-derived neurotrophic factors(BDNFs)play an important role in maintaining synaptic plasticity in learning and memory.Considering AD as a synaptic disorder,BDNF has attracted increasing attention as a potential diagnostic biomarker and a therapeutical molecule for AD.Although depletion of BDNF has been linked with Aβaccumulation,tau phosphorylation,neuroinflammation and neuronal apoptosis,the exact mechanisms underlying the effect of impaired BDNF signaling on AD are still unknown.Here,we present an overview of how BDNF genomic structure is connected to factors that regulate BDNF signaling.We then discuss the role of BDNF in AD and the potential of BDNF-targeting therapeutics for AD.展开更多
Alzheimer’s disease is a neurodegenerative disease that accounts for most of the 50-million dementia cases worldwide in 2018.A large amount of evidence supports the amyloid cascade hypothesis,which states that amyloi...Alzheimer’s disease is a neurodegenerative disease that accounts for most of the 50-million dementia cases worldwide in 2018.A large amount of evidence supports the amyloid cascade hypothesis,which states that amyloid-beta accumulation triggers tau hyperphosphorylation and aggregation in form of neurofibrillary tangles,and these aggregates lead to inflammation,synaptic impairment,neuronal loss,and thus to cognitive decline and behavioral abnormalities.The poor correlation found between cognitive decline and amyloid plaques,have led the scientific community to question whether amyloid-beta accumulation is actually triggering neurodegeneration in Alzheimer’s disease.The occurrence of tau neurofibrillary tangles better correlates to neuronal loss and clinical symptoms and,although amyloid-beta may initiate the cascade of events,tau impairment is likely the effector molecule of neurodegeneration.Recently,it has been shown that amyloid-beta and tau cooperatively work to impair transcription of genes involved in synaptic function and,more importantly,that downregulation of tau partially reverses transcriptional perturbations.Despite mounting evidence points to an interplay between amyloid-beta and tau,some factors could independently affect both pathologies.Thus,the dual pathway hypothesis,which states that there are common upstream triggers causing both amyloid-beta and tau abnormalities has been proposed.Among others,the immune system seems to be strongly involved in amyloid-beta and tau pathologies.Other factors,as the apolipoprotein Eε4 isoform has been suggested to act as a link between amyloid-beta and tau hyperphosphorylation.Interestingly,amyloid-beta-immunotherapy reduces not only amyloid-beta but also tau levels in animal models and in clinical trials.Likewise,it has been shown that tau-immunotherapy also reduces amyloid-beta levels.Thus,even though amyloid-beta immunotherapy is more advanced than tau-immunotherapy,combined amyloid-beta and tau-directed therapies at early stages of the disease have recen展开更多
In addition to senile plaques and cerebral amyloid angiopathy,the hyperphosphorylation of tau protein and formation of intraneuronal neurofibrillary tangles(NFTs)represents another neuropathological hallmark in AD bra...In addition to senile plaques and cerebral amyloid angiopathy,the hyperphosphorylation of tau protein and formation of intraneuronal neurofibrillary tangles(NFTs)represents another neuropathological hallmark in AD brain.Tau is a microtubule-associated protein and localizes predominantly in the axons of neurons with the primary function in maintaining microtubules stability.When the balance between tau phosphorylation and dephosphorylation is changed in favor of the former,tau is hyperphosphorylated and the level of the free tau fractions elevated.The hyperphosphorylation of tau protein and formation of NFTs represent a characteristic neuropathological feature in AD brain.We have discussed the role of Aβin AD in our previous review,this review focused on the recent advances in tau-mediated AD pathology,mainly including tau hyperphosphorylation,propagation of tau pathology and the relationship between tau and Aβ.展开更多
Background Neuropathologically, Alzheimer disease （AD） is characterized by the presence of extracellular plaques enriched in β-amyloid peptides; however, the mechanism by which it results in the neurotoxicity is un...Background Neuropathologically, Alzheimer disease （AD） is characterized by the presence of extracellular plaques enriched in β-amyloid peptides; however, the mechanism by which it results in the neurotoxicity is uncertain. The purpose of this study was to investigate whether it would prompt the progress of Alzheimer disease via enhancement of aberrant phosphorylated tau that results from its increased kinase gene expression. Methods Twenty-four male rats were divided into three groups, and each group had 8 rats： control, sham-operated, and Aβ25-35 injected AD model groups. AD rat models were created by unilateral injections of Aβ25-35 into the amygdala. The hyperphosphorylated tau protein was estimated by immunohistochemistry with paired helical filament-1 （PHF-1） antibody and paired helical filament-tau （AT8） antibody. The expressions of glycogen synthase kinase-3β （GSK-3β） and p38 mitogen-activated protein kinase （P38MAPK） mRNA were observed by in situ hybridization. Results Compared with the control and sham-operated groups, the evaluation of paired AT8 and paired helical filament-1 （PHF-1） in the cortexes and hippocampus of the AD model group showed the numbers of AT8 and PHF-1 positive cells, as well as the optical density （OD） values of the proteins were significantly higher （AT8： in CA2： 0.318±0.037 vs. 0.135±0.028, 0.136±0.031; in frontal cortex： 0.278±0.040 vs. 0.130±0.028, 0.190±0.037. PHF-1 ： in CA2： 0.386±0.034 vs. 0.139±0.010, 0.193±0.041; in frontal cortex： 0.395±0.050 vs. 0.159±0.030, 0.190±0.044, respectively, P 〈0.01）; the number of GSK-3β mRNA and P38MAPK mRNA positive cells of the AD model group, as well as the OD values, also increased significantly in the cortexes, hippocampus （GSK-3β-mRNA： in CA2：0.384±0.012 vs. 0.190±0.015, 0.258±0.064; in frontal cortex： 0.398±0.018 vs. 0.184±0.031, 0.218±0.049. P38MAPK mRNA： in CA2：0.409±0.038 vs. 0.161±0.041, 0.189±0.035; in frontal cortex： 0.423±0.070 vs. 0.160±0展开更多
Contrary to the previous belief that insulin does not act in the brain, studies in the last three decades have demonstrated important roles of insulin and insulin signal transduction in various functions of the centra...Contrary to the previous belief that insulin does not act in the brain, studies in the last three decades have demonstrated important roles of insulin and insulin signal transduction in various functions of the central nervous system. Deregulated brain insulin signaling and its role in molecular pathogenesis have recently been reported in Alzheimer＇s disease （AD）. In this article, we review the roles of brain insulin signaling in memory and cognition, the metabolism of amyloid 13 precursor protein, and tau phosphorylation. We further discuss deficiencies of brain insulin signaling and glucose metabolism, their roles in the development of AD, and recent studies that target the brain insulin signaling pathway for the treatment of AD. It is clear now that deregulation of brain insulin signaling plays an important role in the development of sporadic AD. The brain insulin signaling pathway also offers a promising therapeutic target for treating AD and probably other neurodegenerative disorders.展开更多
基金supported by National Basic Research Development Program(973 Program)of China(2011CBA00400)the National Natural Science Foundation of China(91332201)+1 种基金the Natural Science Foundation of Shanghai Municipality,China(13JC1401500)fund for Medical Emerging Cutting-edge Technology in Shanghai Municipality,China(SHDC12012114)
文摘Oxidative stress plays a significant role in the pathogenesis of Alzheimer＇s disease （AD）, a devastating disease of the elderly. The brain is more vulnerable than other organs to oxidative stress, and most of the components of neurons （lipids, proteins, and nucleic acids） can be oxidized in AD due to mitochondrial dysfunction, increased metal levels, inflammation, and β-amyloid （Aβ） peptides. Oxidative stress participates in the development of AD by promoting Aβ deposition, tau hyperphosphorylation, and the subsequent loss of synapses and neurons. The relationship between oxidative stress and AD suggests that oxidative stress is an essential part of the pathological process, and antioxidants may be useful for AD treatment.
基金supported by the the Chinese Ministry of Science and Technology (2016YFC1306401)
文摘Alzheimer’s disease(AD), the most common type of dementia, is becoming a major challenge for global health and social care. However, the current understanding of AD pathogenesis is limited, and no early diagnosis and disease-modifying therapy are currently available. During the past year, significant progress has been made in clinical research on the diagnosis, prevention, and treatment of AD.In this review, we summarize the latest achievements,including diagnostic biomarkers, polygenic hazard score,amyloid and tau PET imaging, clinical trials targeting amyloid-beta(Ab), tau, and neurotransmitters, early intervention, and primary prevention and systemic intervention approaches, and provide novel perspectives for further efforts to understand and cure the disease.
基金This work was supported by grants from the National Natural Science Foundation of China （No. 81671352, 91232709）, the National Key Project of Research and Development Plan （No. 2016YFC1306404）, the National Institute of Health （No. R21 AG048519, R01 AG021173, R01 AG038710, R01 AG044420, R01 NS046673, RF1 AG056130, and RF1 AG056114）, the Tanz Family Fund as well as scholarship from China Scholarship Council （No. 201608350068）.
文摘Objective：To review recent research advances on tau,a major player in Alzheimer＇s disease （AD） pathogenesis,a biomarker for AD onset,and potential target for AD therapy.Data Sources：This review was based on a comprehensive search using online literature databases,including PubMed,Web of Science,and Google Scholar.Study Selection：Literature search was based on the following keywords：Alzheimer＇s disease,tau protein,biomarker,cerebrospinal fluid （CSF）,therapeutics,plasma,imaging,propagation,spreading,seeding,prion,conformational templating,and posttranslational modification.Relevant articles were carefully reviewed,with no exclusions applied to study design and publication type.Results：Amyloid plaques enriched with extracellular amyloid beta （Aβ） and intracellular neurofibrillary tangles comprised of hyperphosphorylated tau proteins are the two main pathological hallmarks ofAD.Although the Aβ hypothesis has dominated AD research for many years,clinical Aβ-targeting strategies have consistently failed to effectively treat AD or prevent AD onset.The research focus in AD has recently shifted to the role oftau in AD.In addition to phosphorylation,tau is acetylated and proteolytically cleaved,which also contribute to its physiological and pathological functions.Emerging evidence characterizing pathological tau propagation and spreading provides new avenues for research into the molecular and cellular mechanisms underlying AD pathogenesis.Techniques to detect tau at minute levels in CSF and blood have been developed,and improved tracers have facilitated tau imaging in the brain.These advances have potential to accurately determine tau levels at early diagnostic stages in AD.Given that tau is a potential therapeutic target,anti-tau immunotherapy may potentially be a viable treatment strategy in AD intervention.Conclusion：Detecting changes in tau and targeting tau pathology represent a promising lead in the diagnosis and treatment of AD.
基金the support by the Pharmakon Neuroscience Research Network, Dhaka, Bangladesh
文摘Alzheimer’s disease is characterized by the extracellular accumulation of the amyloidβin the form of amyloid plaques and the intracellular deposition of the microtubule-associated protein tau in the form of neurofibrillary tangles.Most of the Alzheimer’s drugs targeting amyloidβhave been failed in clinical trials.Particularly,tau pathology connects greatly in the pathogenesis of Alzheimer’s disease.Tau protein enhances the stabilization of microtubules that leads to the appropriate function of the neuron.Changes in the quantity or the conformation of tau protein could affect its function as a microtubules stabilizer and some of the processes wherein it is involved.The molecular mechanisms leading to the accumulation of tau are principally signified by numerous posttranslational modifications that change its conformation and structural state.Therefore,aberrant phosphorylation,as well as truncation of tau protein,has come into focus as significant mechanisms that make tau protein in a pathological entity.Furthermore,the shape-shifting nature of tau advocates to comprehend the progression of Alzheimer’s disease precisely.In this review,we emphasize the recent studies about the toxic and shape-shifting nature of tau in the pathogenesis of Alzheimer’s disease.
基金supported by a grant from the Health and Family Planning Commission of Hebei Province of China,No.20150033a grant from the Science and Technology Research and Development Project of Handan City of Hebei Province of China,No.152810879-6
文摘Although hypothermia therapy is effective to treat neonatal hypoxic-ischemic encephalopathy,many neonatal patients die or suffer from severe neurological dysfunction.Erythropoietin is considered one of the most promising neuroprotective agents.We hypothesized that erythropoietin combined with hypothermia will improve efficacy of neonatal hypoxic-ischemic encephalopathy treatment.In this study,41 neonates with moderate/severe hypoxic-ischemic encephalopathy were randomly divided into a control group（hypothermia alone for 72 hours,n = 20） and erythropoietin group（hypothermia ＋ erythropoietin 200 IU/kg for 10 days,n = 21）.Our results show that compared with the control group,serum tau protein levels were lower and neonatal behavioral neurological assessment scores higher in the erythropoietin group at 8 and 12 days.However,neurodevelopmental outcome was similar between the two groups at 9 months of age.These findings suggest that erythropoietin combined with hypothermia reduces serum tau protein levels and improves neonatal behavioral neurology outcome but does not affect long-term neurodevelopmental outcome.
基金supported by grants PFB (Basal Financing Program) 12/2007 from the Basal Centre for Excellence in Science and Technology and FONDECYT,No.1120156(to NCI)a pre-doctoral fellowship from the National Commission of Science and Technology of Chile(CONICYT)(to CTR)
文摘Alzheimer＇s disease（AD） is the most common form of dementia in the older population, however, the precise cause of the disease is unknown. The neuropathology is characterized by the presence of aggregates formed by amyloid-β（Aβ） peptide and phosphorylated tau; which is accompanied by progressive impairment of memory. Diverse signaling pathways are linked to AD, and among these the Wnt signaling pathway is becoming increasingly relevant, since it plays essential roles in the adult brain. Initially, Wnt signaling activation was proposed as a neuroprotective mechanism against Aβ toxicity. Later, it was reported that it participates in tau phosphorylation and processes of learning and memory. Interestingly, in the last years we demonstrated that Wnt signaling is fundamental in amyloid precursor protein（APP） processing and that Wnt dysfunction results in Aβ production and aggregation in vitro. Recent in vivo studies reported that loss of canonical Wnt signaling exacerbates amyloid deposition in a transgenic（Tg） mouse model of AD. Finally, we showed that inhibition of Wnt signaling in a Tg mouse previously at the appearance of AD signs, resulted in memory loss, tau phosphorylation and Aβ formation and aggregation; indicating that Wnt dysfunction accelerated the onset of AD. More importantly, Wnt signaling loss promoted cognitive impairment, tau phosphorylation and Aβ1–42 production in the hippocampus of wild-type（WT） mice, contributing to the development of an Alzheimer＇s-like neurophatology. Therefore, in this review we highlight the importance of Wnt/β-catenin signaling dysfunction in the onset of AD and propose that the loss of canonical Wnt signaling is a triggering factor of AD.
基金National Natural Science Foundation of China(81903824)(L.G.).
文摘Synaptic abnormalities are a cardinal feature of Alzheimer’s disease(AD)that are known to arise as the disease progresses.A growing body of evidence suggests that pathological alterations to neuronal circuits and synapses may provide a mechanistic link between amyloidβ(Aβ)and tau pathology and thus may serve as an obligatory relay of the cognitive impairment in AD.Brain-derived neurotrophic factors(BDNFs)play an important role in maintaining synaptic plasticity in learning and memory.Considering AD as a synaptic disorder,BDNF has attracted increasing attention as a potential diagnostic biomarker and a therapeutical molecule for AD.Although depletion of BDNF has been linked with Aβaccumulation,tau phosphorylation,neuroinflammation and neuronal apoptosis,the exact mechanisms underlying the effect of impaired BDNF signaling on AD are still unknown.Here,we present an overview of how BDNF genomic structure is connected to factors that regulate BDNF signaling.We then discuss the role of BDNF in AD and the potential of BDNF-targeting therapeutics for AD.
基金supported by grant SAF2017-89613-R from the Ministerio de Economía y Competitividad(MINECO)/FEDER(Madrid,Spain)(to SV).
文摘Alzheimer’s disease is a neurodegenerative disease that accounts for most of the 50-million dementia cases worldwide in 2018.A large amount of evidence supports the amyloid cascade hypothesis,which states that amyloid-beta accumulation triggers tau hyperphosphorylation and aggregation in form of neurofibrillary tangles,and these aggregates lead to inflammation,synaptic impairment,neuronal loss,and thus to cognitive decline and behavioral abnormalities.The poor correlation found between cognitive decline and amyloid plaques,have led the scientific community to question whether amyloid-beta accumulation is actually triggering neurodegeneration in Alzheimer’s disease.The occurrence of tau neurofibrillary tangles better correlates to neuronal loss and clinical symptoms and,although amyloid-beta may initiate the cascade of events,tau impairment is likely the effector molecule of neurodegeneration.Recently,it has been shown that amyloid-beta and tau cooperatively work to impair transcription of genes involved in synaptic function and,more importantly,that downregulation of tau partially reverses transcriptional perturbations.Despite mounting evidence points to an interplay between amyloid-beta and tau,some factors could independently affect both pathologies.Thus,the dual pathway hypothesis,which states that there are common upstream triggers causing both amyloid-beta and tau abnormalities has been proposed.Among others,the immune system seems to be strongly involved in amyloid-beta and tau pathologies.Other factors,as the apolipoprotein Eε4 isoform has been suggested to act as a link between amyloid-beta and tau hyperphosphorylation.Interestingly,amyloid-beta-immunotherapy reduces not only amyloid-beta but also tau levels in animal models and in clinical trials.Likewise,it has been shown that tau-immunotherapy also reduces amyloid-beta levels.Thus,even though amyloid-beta immunotherapy is more advanced than tau-immunotherapy,combined amyloid-beta and tau-directed therapies at early stages of the disease have recen
基金This work was supported by the grants from the National Natural Science Foundation of China(No.31171019,No.81173108,No.31000574 and No.31200820)the Opening Projects of Shanghai Key Laboratory of Brain Functional Genomics and Key Laboratory of Brain Functional Genomics(East China Normal University),Ministry of Education。
文摘In addition to senile plaques and cerebral amyloid angiopathy,the hyperphosphorylation of tau protein and formation of intraneuronal neurofibrillary tangles(NFTs)represents another neuropathological hallmark in AD brain.Tau is a microtubule-associated protein and localizes predominantly in the axons of neurons with the primary function in maintaining microtubules stability.When the balance between tau phosphorylation and dephosphorylation is changed in favor of the former,tau is hyperphosphorylated and the level of the free tau fractions elevated.The hyperphosphorylation of tau protein and formation of NFTs represent a characteristic neuropathological feature in AD brain.We have discussed the role of Aβin AD in our previous review,this review focused on the recent advances in tau-mediated AD pathology,mainly including tau hyperphosphorylation,propagation of tau pathology and the relationship between tau and Aβ.
基金This study was supported by the grants from the National Natural Science Foundation of China （No. 30971029）, Fund of Shanghai Science and Technology Committee （No. 08411950900）, and Young Excellent Talents Award of Tongji University （No. 2006KJ067）.
文摘Background Neuropathologically, Alzheimer disease （AD） is characterized by the presence of extracellular plaques enriched in β-amyloid peptides; however, the mechanism by which it results in the neurotoxicity is uncertain. The purpose of this study was to investigate whether it would prompt the progress of Alzheimer disease via enhancement of aberrant phosphorylated tau that results from its increased kinase gene expression. Methods Twenty-four male rats were divided into three groups, and each group had 8 rats： control, sham-operated, and Aβ25-35 injected AD model groups. AD rat models were created by unilateral injections of Aβ25-35 into the amygdala. The hyperphosphorylated tau protein was estimated by immunohistochemistry with paired helical filament-1 （PHF-1） antibody and paired helical filament-tau （AT8） antibody. The expressions of glycogen synthase kinase-3β （GSK-3β） and p38 mitogen-activated protein kinase （P38MAPK） mRNA were observed by in situ hybridization. Results Compared with the control and sham-operated groups, the evaluation of paired AT8 and paired helical filament-1 （PHF-1） in the cortexes and hippocampus of the AD model group showed the numbers of AT8 and PHF-1 positive cells, as well as the optical density （OD） values of the proteins were significantly higher （AT8： in CA2： 0.318±0.037 vs. 0.135±0.028, 0.136±0.031; in frontal cortex： 0.278±0.040 vs. 0.130±0.028, 0.190±0.037. PHF-1 ： in CA2： 0.386±0.034 vs. 0.139±0.010, 0.193±0.041; in frontal cortex： 0.395±0.050 vs. 0.159±0.030, 0.190±0.044, respectively, P 〈0.01）; the number of GSK-3β mRNA and P38MAPK mRNA positive cells of the AD model group, as well as the OD values, also increased significantly in the cortexes, hippocampus （GSK-3β-mRNA： in CA2：0.384±0.012 vs. 0.190±0.015, 0.258±0.064; in frontal cortex： 0.398±0.018 vs. 0.184±0.031, 0.218±0.049. P38MAPK mRNA： in CA2：0.409±0.038 vs. 0.161±0.041, 0.189±0.035; in frontal cortex： 0.423±0.070 vs. 0.160±0
基金supported in part by the New York State Office for People with Developmental Disabilitiesthe Second Affiliated Hospital of the School of Medicine,Zhejiang Universitya grant from the U.S.Alzheimer’s Association(IIRG-10-170405)
文摘Contrary to the previous belief that insulin does not act in the brain, studies in the last three decades have demonstrated important roles of insulin and insulin signal transduction in various functions of the central nervous system. Deregulated brain insulin signaling and its role in molecular pathogenesis have recently been reported in Alzheimer＇s disease （AD）. In this article, we review the roles of brain insulin signaling in memory and cognition, the metabolism of amyloid 13 precursor protein, and tau phosphorylation. We further discuss deficiencies of brain insulin signaling and glucose metabolism, their roles in the development of AD, and recent studies that target the brain insulin signaling pathway for the treatment of AD. It is clear now that deregulation of brain insulin signaling plays an important role in the development of sporadic AD. The brain insulin signaling pathway also offers a promising therapeutic target for treating AD and probably other neurodegenerative disorders.
