Brain damage sustained from repeated blows in boxing, wrestling, and other combat sports has serious physical and mental health consequences. The degenerative brain disease, chronic traumatic encephalopathy (CTE), pre...Brain damage sustained from repeated blows in boxing, wrestling, and other combat sports has serious physical and mental health consequences. The degenerative brain disease, chronic traumatic encephalopathy (CTE), presents clinically with memory loss, aggression, difficulty in rational thinking and other cognitive problems. This spectrum, which mimics Alzheimer’s disease, is diagnosed post-mortem through a brain biopsy in many professional athletes. However, little is known about the process of development and how to identify vulnerable individuals who may be on course for developing CTE. Boxing is a sport that has a severe toll on athletes’ health, primarily on their brain health and function. This review addresses the concerns of brain injury, describes the pathologies that manifest in multiple scales, e.g., molecular and cognitive, and also proposes possible diagnostic and prognostic markers to characterize the early onset of CTE along with the aim to identify a starting point for future precautions and interventions.展开更多
Alzheimer’s disease(AD)is a progressive and neurodegenerative illness which results in alterations in cognitive development.It is characterized by loss/dysfunction of cholinergic neurons,and formation of amyloid plaq...Alzheimer’s disease(AD)is a progressive and neurodegenerative illness which results in alterations in cognitive development.It is characterized by loss/dysfunction of cholinergic neurons,and formation of amyloid plaques,and formation of neurofibrillary tangles,among other changes,due to hyperphosphorylation of tau-protein.Exposure to pesticides in humans occurs frequently due to contact with contaminated food,water,or particles.Organochlorines,organophosphates,carbamates,pyrethroids and neonicotinoids are associated with the most diagnosed incidents of severe cognitive impairment.The aim of this study was to determine the effects of these pesticides on the phosphorylation of tau protein,and its cognitive implications in the development of AD.It was found that exposure to pesticides increased the phosphorylation of tau protein at sites Ser198,Ser199,Ser202,Thr205,Ser396 and Ser404.Contact with these chemicals altered the enzymatic activities of cyclin-dependent kinase 5 and glycogen synthase kinase 3 beta,and protein phosphatase-2A.Moreover,it altered the expression of the microtubule associated protein tau gene,and changed levels of intracellular calcium.These changes affected tau protein phosphorylation and neuroinflammation,and also increased oxidative stress.In addition,the exposed subjects had poor level of performance in tests that involved evaluation of novelty,as test on verbal,non-verbal,spatial memory,attention,and problem-solving skills.展开更多
BACKGROUND： The differential diagnosis of many neurodegenerative disorders depends primarily on clinical symptoms together with imaging methods. Recently, increased importance has been placed on the use of biomarkers...BACKGROUND： The differential diagnosis of many neurodegenerative disorders depends primarily on clinical symptoms together with imaging methods. Recently, increased importance has been placed on the use of biomarkers for diagnosing various neurodegenerative disorders. OBJECTIVE： To assess the feasibility of tau-protein, phosphorylated tau-protein, beta-amyloid 42 （Aβ42）, and 14-3-3 protein as biomarkers for diagnosing several neurodegenerative diseases complicated by cognitive deficits. DESIGN, TIME AND SETTING： A non-randomized, concurrent, case-control investigation was performed in three medical centers in the Czech Republic （Department of Neurology at the University Hospital in Hradec Kralove, Department of Neurology at the 2rd Medical Faculty, and the University Hospital Motol） between October 2000 and November 2006. PARTICIPANTS： Eighteen patients with probable AIzheimer＇s disease, 4 patients with Creutzfeldt-Jakob disease, 10 patients with frontotemporal dementia, 9 patients with clinically isolated syndrome suggestive of multiple sclerosis, and 7 patients with multiple sclerosis, as well as 38 race-, nationality-, and age-matched cognitively intact controls, were included in the study. Diagnoses were established based on the following criteria： the criteria for Alzheimer＇s disease proposed by the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer＇s Disease and Related Disorders Association, WHO criteria for Creutzfeldt-Jakob disease, Neary criteria for frontotemporal dementia, and McDonald＇s criteria for multiple sclerosis. All included patients were confirmed to suffer from various degrees of dementia. METHODS： Enzyme-linked immunosorbent assay was used to measure concentrations of tau-protein, phosphorylated tau-protein, and Aβ42 in cerebrospinal fluid （CSF） samples collected by standard lumbar puncture from each patient. Moreover, 14-3-3 protein was assessed by Western blot in CSF of Creutzfeldt-Jakob disease patients. Cognitive status was assessed using the Mini Mental Scale Examination （MMSE） in all subjects. MAIN OUTCOME MEASURES： Establishment of biomarkers with greatest specificity and sensitivity for the investigated disorders according to Receiver Operating Characteristic curves, which were based on values from patients and controls; correlation between concentrations of given biomarkers and demographic parameters, diagnosis, duration of disease, and level of cognitive deficit. RESULTS： Increased concentrations of total tau protein and phosphorylated tau protein, and decreased levels of Aβ42, in CSF of Alzheimer＇s disease patients reached the required sensitivity/specificity ratio of 80% or greater. A marked elevation in CSF concentrations of total tau protein showed even greater sensitivity than 14-3-3 protein in Creutzfeldt-Jakob disease. There was no association between selected biomarkers and frontotemporal dementia or multiple sclerosis. Phosphorylated tau-protein was the only biomarker that noticeably correlated with MMSE scores for Alzheimer＇s disease.CONCLUSION： Levels of total tau protein, phosphorylated tau protein, and A!342 in the CSF could differentiate patients with Alzheimer＇s disease and Creutzfeldt-Jakob disease from healthy controls and patients with other neurodegenerative disorders. The diversity of absolute values demonstrates the necessity to establish a specific standard for each laboratory.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
As a key contributor to memory storage, the synapse is one of the earliest affected neuronal components in Alzheimer＇s disease （AD）. Under physiological conditions, the synaptic con- nections between neurons underg...As a key contributor to memory storage, the synapse is one of the earliest affected neuronal components in Alzheimer＇s disease （AD）. Under physiological conditions, the synaptic con- nections between neurons undergo activity-dependent func- tional and morphological re-organisation. This dynamic, ＇plastic＇ neural ability critically depends on the structural integrity of the synapse. Thus, proteins that are implicated in preserving the organisation and dynamics of synaptic connections, including microtubules of the cytoskeleton and associated proteins, have attracted much focus for their involvement in the malfunction- ing AD synapse.展开更多
[Objectives] To study the effects and mechanism of notoginsenoside Rg1 on the spatial learning and memory and phosphorylated tau protein in the AD( Alzheimer's Disease) model rat. [Methods]The AD model rat was rep...[Objectives] To study the effects and mechanism of notoginsenoside Rg1 on the spatial learning and memory and phosphorylated tau protein in the AD( Alzheimer's Disease) model rat. [Methods]The AD model rat was replicated by injection of Aβ_(25-35) in the left lateral ventricles of SD rats. The low dose( 25 mg/kg),middle dose( 50 mg/kg) and high dose( 100 mg/kg) notoginsenoside Rg1 was used for intragastric administration,respectively,two times every day. After 4 weeks,the Morris water maze test was done to detect the learning and memory capacity,and the immunoblotting,immunohistochemical methods were used to detect the changes in the phosphorylation level and distribution of tau protein in hippocampus of the rats. [Results] After the intracerebroventricular injection of Aβ_(25-35),the learning and memory capacity of the model rats was significantly lower than the learning and memory capacity of the normal control rats. The immunoblotting test results showed that the phosphorylation level of tau protein threonine 231 site( Thr231) in hippocampus was significantly increased,and the nonphosphorylation level was significantly decreased. The morphological testing results showed that the phosphorylation level of tau protein Thr231 of AD model rats was increased markedly in region of DG,CA1 and CA3 of the hippocampus. The intervention of the middle dose notoginsenoside Rg1 could significantly improve the learning and memory capacity of the model rats in Morris water maze. The notoginsenoside Rg1 in three different doses could all reduce the phosphorylation level of tau protein Thr231 in the hippocampal DG,CA1,CA3 regions,and there were no significant differences among the three doses. [Conclusions]The notoginsenoside Rg1 could improve Aβ_(25-35)-induced spatial learning and memory impairment of the AD model rats,and decreased the phosphorylation level of tau protein in hippocampus.展开更多
Transient brain ischemia has been shown to induce hyperphosphorylation of the micro- tubule-associated protein tau. To further determine the mechanisms underlying these processes, we investigated the interaction betwe...Transient brain ischemia has been shown to induce hyperphosphorylation of the micro- tubule-associated protein tau. To further determine the mechanisms underlying these processes, we investigated the interaction between tau, glycogen synthase kinase （GSK）-313 and protein phos- phatase 2A. The results confirmed that tau protein was dephosphorylated during brain ischemia; in addition, the activity of GSK-3β was increased and the activity of protein phosphatase 2A was de- creased. After reperfusion, tau protein was hyperphosphorylated, the activity of GSK-3β was de- creased and the activity of protein phosphatase 2A remained low. Importantly, the interaction of tau with GSK-3β and protein phosphatase 2A was altered during ischemia and reperfusion. Lithium chloride could affect tau phosphorylation by regulating the interaction of tau with GSK-3β and pro- tein phosphatase 2A, and improve learning and memory ability of rats after transient brain ischemia. The present study demonstrated that it was the interaction of tau with GSK-3β and protein phos- phatase 2A, rather than their individual activities, that dominates the phosphorylation of tau in tran- sient brain ischemia. Hyperphosphorylated tau protein may play an important role in the evolution of brain injury in ischemic stroke. The neuroprotective effects of lithium chloride partly depend on the inhibition of tau phosphorylation during transient brain ischemia.展开更多
BACKGROUND： Previous studies have shown that heat shock protein 70 （HSP70） has neuroprotective effects by decreasing phosphorylation of Tau protein, thereby reducing the expression of Tau protein and proper aggrega...BACKGROUND： Previous studies have shown that heat shock protein 70 （HSP70） has neuroprotective effects by decreasing phosphorylation of Tau protein, thereby reducing the expression of Tau protein and proper aggregation. OBJECTIVE： To observe and verify expressional changes of HSP70 and Tau in retinal ganglion cells following stretch injury to the right optic nerve in rats, and to determine the effect of heat stress pretreatment on HSP70 and Tau protein expressions. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Neurology Research Institute of the First Affiliated Hospital of Chongqing Medical University from March to June 2006. MATERIALS： Instant SABC immunohistochemistry kit, as well as mouse anti-HSP70 and rabbit anti-Tau polyclonal antibodies, were purchased from Wuhan Boster Bioengineering Limited, China. METHODS： A total of 57 male, Wistar rats were randomly assigned to 4 groups： control （n = 3）; 150-180 g stretch force was induced in the right optic nerves in stretch-only group （n = 18） to establish optic nerve stretch injury model; heat stress was applied to 18 animals in heat-stress treatment group; 18 rats in the heat-stress pretreatment plus stretch group were subjected to identical stretch injury as stretch-only group after 24-hour heat-stress pretreatment. According to sacrifice time, the groups were assigned to 6 subgroups at different time points of 4, 8, and 16 hours, and 1,3, and 5 days, with 3 rats in each subgroup. No treatment was performed in the control group except anesthesia. MAIN OUTCOME MEASURES： Morphological changes of optic nerves and retinal ganglion cells following stretch injury were observed by light microscopy following hematoxylin-eosin staining. HSP70 and Tau protein expression levels were observed in retinal ganglial cells from each group using im munohistochemistry. RESULTS： （1） Compared with the control group, morphological axonal and retinal ganglial cell changes, as well as a decreased number of retinal ganglial cells, were identified in the stretch-only group （P 〈 0.01）. Pathological damage in optical nerve and retinal ganglial cells were not remarkable in the heat-stress pretreatment plus stretch group, with no statistical difference in the number of retinal ganglial cells compared with the control group （P 〉 0.05）. （2） Compared with the control group significantly increased HSP70 expression in retinal ganglial cells occurred in the stretch-only, heat-stress treatment, and heat-stress pretreatment plus stretch groups （P 〈 0.05 or P 〈 0.01 ）. The peak of HSP70 expression was earlier in the heat-stress pretreatment plus stretch group compared with the stretch-only and heat-stress treatment groups, and was expressed over a longer period of time compared with the heat-stress treatment group. Compared with the control group, Tau expression in the retinal ganglial cells rapidly increased 4-16 hours following stretch injury in the stretch-only group （P 〈 0.05 or P 〈 0.01）, and obviously decreased in the heat-stress pretreatment plus stretch group （P 〈 0.05 or P 〈 0.01 ）. CONCLUSION： Tau expression increased following stretch injury, with an earlier expression peak than HSP70, which indicated that stretch injury-induced HSP70 expression was not strong or quick enough to sufficiently protect the nerve. A much more enhanced HSP70 expression, with an earlier peak and longer expression period, was observed in rats subjected to stretch injury following heat stress, which demonstrated that HSP70 exhibited neuroprotective functions by reducing abnormal aggregation of Tau.展开更多
Objective To explore the possible neurophysiologic mechanisms of propofol and N-methyl-Daspartate(NMDA) receptor antagonist against learning-memory impairment of depressed rats without olfactory bulbs. Methods Models ...Objective To explore the possible neurophysiologic mechanisms of propofol and N-methyl-Daspartate(NMDA) receptor antagonist against learning-memory impairment of depressed rats without olfactory bulbs. Methods Models of depressed rats without olfactory bulbs were established. For the factorial design in analysis of variance, two intervention factors were included: electroconvulsive shock groups(with and without a course of electroconvulsive shock) and drug intervention groups [intraperotoneal(ip) injection of saline, NMDA receptor antagonist MK-801 and propofol. A total of 60 adult depressed rats without olfactory bulbs were randomly divided into 6 experimental groups(n=10 per group): ip injection of 5 ml saline; ip injection of 5 ml of 10 mg/kg MK-801; ip injection of 5 ml of 10 mg/kg MK-801 and a course of electroconvulsive shock; ip injection of 5 ml of 200 mg/kg propofol; ip injection of 5 ml of 200 mg/kg propofol and a course of electroconvulsive shock; and ip injection of 5 ml saline and a course of electroconvulsive shock. The learning-memory abilities of the rats was evaluated by the Morris water maze test. The content of glutamic acid in the hippocampus was detected by high-performance liquid chromatography. The expressions of p-AT8Ser202 in the hippocampus were determined by Western blot analysis. Results Propofol, MK-801 or electroconvulsive shock alone induced learning-memory impairment in depressed rats, as proven by extended evasive latency time and shortened space probe time. Glutamic acid content in the hippocampus of depressed rats was significantly up-regulated by electroconvulsive shock and down-regulated by propofol, but MK-801 had no significant effect on glutamic acid content. Levels ofphosphorylated Tau protein p-AT8Ser202 in the hippocampus was up-regulated by electroconvulsive shock but was reduced by propofol and MK-801 alone. Propofol prevented learning-memory impairment and reduced glutamic acid content and p-AT8Ser202 levels induced by electroconvulsive shock. Conclusion Electroconvulsive shock might reduce learning-memory impairment caused by protein Tau hyperphosphorylation in depressed rats by down-regulating glutamate content.展开更多
The impact of apolipoprotein E(ApoE)isoforms on sporadic Alzheimer's disease has long been studied;however,the influences of apolipoprotein E gene(APOE)on healthy and pathological human brains are not fully unders...The impact of apolipoprotein E(ApoE)isoforms on sporadic Alzheimer's disease has long been studied;however,the influences of apolipoprotein E gene(APOE)on healthy and pathological human brains are not fully understood.ApoE exists as three common isoforms(ApoE2,ApoE3,and ApoE4),which differ in two amino acid residues.Traditionally,ApoE binds cholesterol and phospholipids and ApoE isoforms display diffe rent affinities for their receptors,lipids transport and distribution in the brain and periphery.The role of ApoE in the human depends on ApoE isoforms,brain regions,aging,and neural injury.APOE E4 is the strongest genetic risk factor for sporadic Alzheimer's disease,considering its role in influencing amyloid-beta metabolism.The exact mechanisms by which APOE gene variants may increase or decrease Alzheimer's disease risk are not fully understood,but APOE was also known to affect directly and indirectly tau-mediated neurodegeneration,lipids metabolism,neurovascular unit,and microglial function.Consistent with the biological function of ApoE,ApoE4 isoform significantly alte red signaling pathways associated with cholesterol homeostasis,transport,and myelination.Also,the rare protective APOE variants confirm that ApoE plays an important role in Alzheimer's disease pathogenesis.The objectives of the present mini-review were to describe classical and new roles of various ApoE isoforms in Alzheimer's disease pathophysiology beyond the deposition of amyloid-beta and to establish a functional link between APOE,brain function,and memory,from a molecular to a clinical level.APOE genotype also exerted a heterogeneous effect on clinical Alzheimer's disease phenotype and its outcomes.Not only in learning and memory but also in neuro psychiatric symptoms that occur in a premorbid condition.Cla rifying the relationships between Alzheimer's disease-related pathology with neuropsychiatric symptoms,particularly suicidal ideation in Alzheimer's disease patients,may be useful for elucidating also the underlying pathophysiological process and its prognosis.Also,the effects of anti-amyloid-beta drugs,recently approved for the treatment of Alzheimer's disease,could be influenced by the APOE genotype.展开更多
文摘Brain damage sustained from repeated blows in boxing, wrestling, and other combat sports has serious physical and mental health consequences. The degenerative brain disease, chronic traumatic encephalopathy (CTE), presents clinically with memory loss, aggression, difficulty in rational thinking and other cognitive problems. This spectrum, which mimics Alzheimer’s disease, is diagnosed post-mortem through a brain biopsy in many professional athletes. However, little is known about the process of development and how to identify vulnerable individuals who may be on course for developing CTE. Boxing is a sport that has a severe toll on athletes’ health, primarily on their brain health and function. This review addresses the concerns of brain injury, describes the pathologies that manifest in multiple scales, e.g., molecular and cognitive, and also proposes possible diagnostic and prognostic markers to characterize the early onset of CTE along with the aim to identify a starting point for future precautions and interventions.
文摘Alzheimer’s disease(AD)is a progressive and neurodegenerative illness which results in alterations in cognitive development.It is characterized by loss/dysfunction of cholinergic neurons,and formation of amyloid plaques,and formation of neurofibrillary tangles,among other changes,due to hyperphosphorylation of tau-protein.Exposure to pesticides in humans occurs frequently due to contact with contaminated food,water,or particles.Organochlorines,organophosphates,carbamates,pyrethroids and neonicotinoids are associated with the most diagnosed incidents of severe cognitive impairment.The aim of this study was to determine the effects of these pesticides on the phosphorylation of tau protein,and its cognitive implications in the development of AD.It was found that exposure to pesticides increased the phosphorylation of tau protein at sites Ser198,Ser199,Ser202,Thr205,Ser396 and Ser404.Contact with these chemicals altered the enzymatic activities of cyclin-dependent kinase 5 and glycogen synthase kinase 3 beta,and protein phosphatase-2A.Moreover,it altered the expression of the microtubule associated protein tau gene,and changed levels of intracellular calcium.These changes affected tau protein phosphorylation and neuroinflammation,and also increased oxidative stress.In addition,the exposed subjects had poor level of performance in tests that involved evaluation of novelty,as test on verbal,non-verbal,spatial memory,attention,and problem-solving skills.
文摘BACKGROUND： The differential diagnosis of many neurodegenerative disorders depends primarily on clinical symptoms together with imaging methods. Recently, increased importance has been placed on the use of biomarkers for diagnosing various neurodegenerative disorders. OBJECTIVE： To assess the feasibility of tau-protein, phosphorylated tau-protein, beta-amyloid 42 （Aβ42）, and 14-3-3 protein as biomarkers for diagnosing several neurodegenerative diseases complicated by cognitive deficits. DESIGN, TIME AND SETTING： A non-randomized, concurrent, case-control investigation was performed in three medical centers in the Czech Republic （Department of Neurology at the University Hospital in Hradec Kralove, Department of Neurology at the 2rd Medical Faculty, and the University Hospital Motol） between October 2000 and November 2006. PARTICIPANTS： Eighteen patients with probable AIzheimer＇s disease, 4 patients with Creutzfeldt-Jakob disease, 10 patients with frontotemporal dementia, 9 patients with clinically isolated syndrome suggestive of multiple sclerosis, and 7 patients with multiple sclerosis, as well as 38 race-, nationality-, and age-matched cognitively intact controls, were included in the study. Diagnoses were established based on the following criteria： the criteria for Alzheimer＇s disease proposed by the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer＇s Disease and Related Disorders Association, WHO criteria for Creutzfeldt-Jakob disease, Neary criteria for frontotemporal dementia, and McDonald＇s criteria for multiple sclerosis. All included patients were confirmed to suffer from various degrees of dementia. METHODS： Enzyme-linked immunosorbent assay was used to measure concentrations of tau-protein, phosphorylated tau-protein, and Aβ42 in cerebrospinal fluid （CSF） samples collected by standard lumbar puncture from each patient. Moreover, 14-3-3 protein was assessed by Western blot in CSF of Creutzfeldt-Jakob disease patients. Cognitive status was assessed using the Mini Mental Scale Examination （MMSE） in all subjects. MAIN OUTCOME MEASURES： Establishment of biomarkers with greatest specificity and sensitivity for the investigated disorders according to Receiver Operating Characteristic curves, which were based on values from patients and controls; correlation between concentrations of given biomarkers and demographic parameters, diagnosis, duration of disease, and level of cognitive deficit. RESULTS： Increased concentrations of total tau protein and phosphorylated tau protein, and decreased levels of Aβ42, in CSF of Alzheimer＇s disease patients reached the required sensitivity/specificity ratio of 80% or greater. A marked elevation in CSF concentrations of total tau protein showed even greater sensitivity than 14-3-3 protein in Creutzfeldt-Jakob disease. There was no association between selected biomarkers and frontotemporal dementia or multiple sclerosis. Phosphorylated tau-protein was the only biomarker that noticeably correlated with MMSE scores for Alzheimer＇s disease.CONCLUSION： Levels of total tau protein, phosphorylated tau protein, and A!342 in the CSF could differentiate patients with Alzheimer＇s disease and Creutzfeldt-Jakob disease from healthy controls and patients with other neurodegenerative disorders. The diversity of absolute values demonstrates the necessity to establish a specific standard for each laboratory.
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 grant SDU2020 to Prof.Bente Finsen and Prof.Martin R.Larsen(COPING AD–Collaborative Project on the Interaction between Neurons and Glia in Alzheimer’s Disease)
文摘As a key contributor to memory storage, the synapse is one of the earliest affected neuronal components in Alzheimer＇s disease （AD）. Under physiological conditions, the synaptic con- nections between neurons undergo activity-dependent func- tional and morphological re-organisation. This dynamic, ＇plastic＇ neural ability critically depends on the structural integrity of the synapse. Thus, proteins that are implicated in preserving the organisation and dynamics of synaptic connections, including microtubules of the cytoskeleton and associated proteins, have attracted much focus for their involvement in the malfunction- ing AD synapse.
基金Supported by National Natural Science Foundation of China(81673856,81573865)China Postdoctoral Science Foundation(2016M592319,2017T100542)+1 种基金Youth Project of Hubei University of Traditional Chinese Medicine(Zhong Yi Xiao Zi2015182)PhD Research Foundation of Hubei University of Traditional Chinese Medicine(Zhong Yi Dang Zi201425)
文摘[Objectives] To study the effects and mechanism of notoginsenoside Rg1 on the spatial learning and memory and phosphorylated tau protein in the AD( Alzheimer's Disease) model rat. [Methods]The AD model rat was replicated by injection of Aβ_(25-35) in the left lateral ventricles of SD rats. The low dose( 25 mg/kg),middle dose( 50 mg/kg) and high dose( 100 mg/kg) notoginsenoside Rg1 was used for intragastric administration,respectively,two times every day. After 4 weeks,the Morris water maze test was done to detect the learning and memory capacity,and the immunoblotting,immunohistochemical methods were used to detect the changes in the phosphorylation level and distribution of tau protein in hippocampus of the rats. [Results] After the intracerebroventricular injection of Aβ_(25-35),the learning and memory capacity of the model rats was significantly lower than the learning and memory capacity of the normal control rats. The immunoblotting test results showed that the phosphorylation level of tau protein threonine 231 site( Thr231) in hippocampus was significantly increased,and the nonphosphorylation level was significantly decreased. The morphological testing results showed that the phosphorylation level of tau protein Thr231 of AD model rats was increased markedly in region of DG,CA1 and CA3 of the hippocampus. The intervention of the middle dose notoginsenoside Rg1 could significantly improve the learning and memory capacity of the model rats in Morris water maze. The notoginsenoside Rg1 in three different doses could all reduce the phosphorylation level of tau protein Thr231 in the hippocampal DG,CA1,CA3 regions,and there were no significant differences among the three doses. [Conclusions]The notoginsenoside Rg1 could improve Aβ_(25-35)-induced spatial learning and memory impairment of the AD model rats,and decreased the phosphorylation level of tau protein in hippocampus.
基金supported by the National High Technology Research and Development Program of China(863 Program),No.2012AA020905the Biological Industry Development Funds of Shenzhen,No.JC201005260093A+1 种基金the National Natural Science Foundation of China/Research Grants Council Joint Research Scheme,No.81161160570the National Natural Science Foundation of China,No.81171143the Tsinghua-Yue-Yuen Medical Sciences Fund
文摘Transient brain ischemia has been shown to induce hyperphosphorylation of the micro- tubule-associated protein tau. To further determine the mechanisms underlying these processes, we investigated the interaction between tau, glycogen synthase kinase （GSK）-313 and protein phos- phatase 2A. The results confirmed that tau protein was dephosphorylated during brain ischemia; in addition, the activity of GSK-3β was increased and the activity of protein phosphatase 2A was de- creased. After reperfusion, tau protein was hyperphosphorylated, the activity of GSK-3β was de- creased and the activity of protein phosphatase 2A remained low. Importantly, the interaction of tau with GSK-3β and protein phosphatase 2A was altered during ischemia and reperfusion. Lithium chloride could affect tau phosphorylation by regulating the interaction of tau with GSK-3β and pro- tein phosphatase 2A, and improve learning and memory ability of rats after transient brain ischemia. The present study demonstrated that it was the interaction of tau with GSK-3β and protein phos- phatase 2A, rather than their individual activities, that dominates the phosphorylation of tau in tran- sient brain ischemia. Hyperphosphorylated tau protein may play an important role in the evolution of brain injury in ischemic stroke. The neuroprotective effects of lithium chloride partly depend on the inhibition of tau phosphorylation during transient brain ischemia.
基金Supported by: A Fund from Ministry of Health of Chongqing, No.99-4004
文摘BACKGROUND： Previous studies have shown that heat shock protein 70 （HSP70） has neuroprotective effects by decreasing phosphorylation of Tau protein, thereby reducing the expression of Tau protein and proper aggregation. OBJECTIVE： To observe and verify expressional changes of HSP70 and Tau in retinal ganglion cells following stretch injury to the right optic nerve in rats, and to determine the effect of heat stress pretreatment on HSP70 and Tau protein expressions. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Neurology Research Institute of the First Affiliated Hospital of Chongqing Medical University from March to June 2006. MATERIALS： Instant SABC immunohistochemistry kit, as well as mouse anti-HSP70 and rabbit anti-Tau polyclonal antibodies, were purchased from Wuhan Boster Bioengineering Limited, China. METHODS： A total of 57 male, Wistar rats were randomly assigned to 4 groups： control （n = 3）; 150-180 g stretch force was induced in the right optic nerves in stretch-only group （n = 18） to establish optic nerve stretch injury model; heat stress was applied to 18 animals in heat-stress treatment group; 18 rats in the heat-stress pretreatment plus stretch group were subjected to identical stretch injury as stretch-only group after 24-hour heat-stress pretreatment. According to sacrifice time, the groups were assigned to 6 subgroups at different time points of 4, 8, and 16 hours, and 1,3, and 5 days, with 3 rats in each subgroup. No treatment was performed in the control group except anesthesia. MAIN OUTCOME MEASURES： Morphological changes of optic nerves and retinal ganglion cells following stretch injury were observed by light microscopy following hematoxylin-eosin staining. HSP70 and Tau protein expression levels were observed in retinal ganglial cells from each group using im munohistochemistry. RESULTS： （1） Compared with the control group, morphological axonal and retinal ganglial cell changes, as well as a decreased number of retinal ganglial cells, were identified in the stretch-only group （P 〈 0.01）. Pathological damage in optical nerve and retinal ganglial cells were not remarkable in the heat-stress pretreatment plus stretch group, with no statistical difference in the number of retinal ganglial cells compared with the control group （P 〉 0.05）. （2） Compared with the control group significantly increased HSP70 expression in retinal ganglial cells occurred in the stretch-only, heat-stress treatment, and heat-stress pretreatment plus stretch groups （P 〈 0.05 or P 〈 0.01 ）. The peak of HSP70 expression was earlier in the heat-stress pretreatment plus stretch group compared with the stretch-only and heat-stress treatment groups, and was expressed over a longer period of time compared with the heat-stress treatment group. Compared with the control group, Tau expression in the retinal ganglial cells rapidly increased 4-16 hours following stretch injury in the stretch-only group （P 〈 0.05 or P 〈 0.01）, and obviously decreased in the heat-stress pretreatment plus stretch group （P 〈 0.05 or P 〈 0.01 ）. CONCLUSION： Tau expression increased following stretch injury, with an earlier expression peak than HSP70, which indicated that stretch injury-induced HSP70 expression was not strong or quick enough to sufficiently protect the nerve. A much more enhanced HSP70 expression, with an earlier peak and longer expression period, was observed in rats subjected to stretch injury following heat stress, which demonstrated that HSP70 exhibited neuroprotective functions by reducing abnormal aggregation of Tau.
基金Supported by the National Natural Science Foundation(30972831)the China Postdoctoral Science Foundation(2013M530880)
文摘Objective To explore the possible neurophysiologic mechanisms of propofol and N-methyl-Daspartate(NMDA) receptor antagonist against learning-memory impairment of depressed rats without olfactory bulbs. Methods Models of depressed rats without olfactory bulbs were established. For the factorial design in analysis of variance, two intervention factors were included: electroconvulsive shock groups(with and without a course of electroconvulsive shock) and drug intervention groups [intraperotoneal(ip) injection of saline, NMDA receptor antagonist MK-801 and propofol. A total of 60 adult depressed rats without olfactory bulbs were randomly divided into 6 experimental groups(n=10 per group): ip injection of 5 ml saline; ip injection of 5 ml of 10 mg/kg MK-801; ip injection of 5 ml of 10 mg/kg MK-801 and a course of electroconvulsive shock; ip injection of 5 ml of 200 mg/kg propofol; ip injection of 5 ml of 200 mg/kg propofol and a course of electroconvulsive shock; and ip injection of 5 ml saline and a course of electroconvulsive shock. The learning-memory abilities of the rats was evaluated by the Morris water maze test. The content of glutamic acid in the hippocampus was detected by high-performance liquid chromatography. The expressions of p-AT8Ser202 in the hippocampus were determined by Western blot analysis. Results Propofol, MK-801 or electroconvulsive shock alone induced learning-memory impairment in depressed rats, as proven by extended evasive latency time and shortened space probe time. Glutamic acid content in the hippocampus of depressed rats was significantly up-regulated by electroconvulsive shock and down-regulated by propofol, but MK-801 had no significant effect on glutamic acid content. Levels ofphosphorylated Tau protein p-AT8Ser202 in the hippocampus was up-regulated by electroconvulsive shock but was reduced by propofol and MK-801 alone. Propofol prevented learning-memory impairment and reduced glutamic acid content and p-AT8Ser202 levels induced by electroconvulsive shock. Conclusion Electroconvulsive shock might reduce learning-memory impairment caused by protein Tau hyperphosphorylation in depressed rats by down-regulating glutamate content.
文摘The impact of apolipoprotein E(ApoE)isoforms on sporadic Alzheimer's disease has long been studied;however,the influences of apolipoprotein E gene(APOE)on healthy and pathological human brains are not fully understood.ApoE exists as three common isoforms(ApoE2,ApoE3,and ApoE4),which differ in two amino acid residues.Traditionally,ApoE binds cholesterol and phospholipids and ApoE isoforms display diffe rent affinities for their receptors,lipids transport and distribution in the brain and periphery.The role of ApoE in the human depends on ApoE isoforms,brain regions,aging,and neural injury.APOE E4 is the strongest genetic risk factor for sporadic Alzheimer's disease,considering its role in influencing amyloid-beta metabolism.The exact mechanisms by which APOE gene variants may increase or decrease Alzheimer's disease risk are not fully understood,but APOE was also known to affect directly and indirectly tau-mediated neurodegeneration,lipids metabolism,neurovascular unit,and microglial function.Consistent with the biological function of ApoE,ApoE4 isoform significantly alte red signaling pathways associated with cholesterol homeostasis,transport,and myelination.Also,the rare protective APOE variants confirm that ApoE plays an important role in Alzheimer's disease pathogenesis.The objectives of the present mini-review were to describe classical and new roles of various ApoE isoforms in Alzheimer's disease pathophysiology beyond the deposition of amyloid-beta and to establish a functional link between APOE,brain function,and memory,from a molecular to a clinical level.APOE genotype also exerted a heterogeneous effect on clinical Alzheimer's disease phenotype and its outcomes.Not only in learning and memory but also in neuro psychiatric symptoms that occur in a premorbid condition.Cla rifying the relationships between Alzheimer's disease-related pathology with neuropsychiatric symptoms,particularly suicidal ideation in Alzheimer's disease patients,may be useful for elucidating also the underlying pathophysiological process and its prognosis.Also,the effects of anti-amyloid-beta drugs,recently approved for the treatment of Alzheimer's disease,could be influenced by the APOE genotype.
