Regulator of G protein signaling 6 mediates exercise-induced recovery of hippocampal neurogenesis,learning,and memory in a mouse model of Alzheimer’s disease

Hippocampal neuronal loss causes cognitive dysfunction in Alzheimer’s disease.Adult hippocampal neurogenesis is reduced in patients with Alzheimer’s disease.Exercise stimulates adult hippocampal neurogenesis in rodents and improves memory and slows cognitive decline in patients with Alzheimer’s disease.However,the molecular pathways for exercise-induced adult hippocampal neurogenesis and improved cognition in Alzheimer’s disease are poorly understood.Recently,regulator of G protein signaling 6(RGS6)was identified as the mediator of voluntary running-induced adult hippocampal neurogenesis in mice.Here,we generated novel RGS6fl/fl;APP_(SWE) mice and used retroviral approaches to examine the impact of RGS6 deletion from dentate gyrus neuronal progenitor cells on voluntary running-induced adult hippocampal neurogenesis and cognition in an amyloid-based Alzheimer’s disease mouse model.We found that voluntary running in APP_(SWE) mice restored their hippocampal cognitive impairments to that of control mice.This cognitive rescue was abolished by RGS6 deletion in dentate gyrus neuronal progenitor cells,which also abolished running-mediated increases in adult hippocampal neurogenesis.Adult hippocampal neurogenesis was reduced in sedentary APP_(SWE) mice versus control mice,with basal adult hippocampal neurogenesis reduced by RGS6 deletion in dentate gyrus neural precursor cells.RGS6 was expressed in neurons within the dentate gyrus of patients with Alzheimer’s disease with significant loss of these RGS6-expressing neurons.Thus,RGS6 mediated voluntary running-induced rescue of impaired cognition and adult hippocampal neurogenesis in APP_(SWE) mice,identifying RGS6 in dentate gyrus neural precursor cells as a possible therapeutic target in Alzheimer’s disease.

Emerging structures and dynamic mechanisms ofγ-secretase for Alzheimer’s disease

γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface receptors.Mutations inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well.However,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-secretase.In this review,we focus on recent studies of structural dynamic mechanisms ofγ-secretase.Different mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics simulations.While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental findings.The approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-secretase.In addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is discussed.Finally,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations of theγ-secretase-substrate complexes.Comprehensive understanding of the functional mechanisms ofγ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general.

Mutations of beta-amyloid precursor protein alter the consequence of Alzheimer's disease pathogenesis

Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer's disease. To date, the mechanism underlying the effect of APP mutation on Aβ generation is unclear. Therefore, investigating the mechanism of APP mutation on Alzheimer's disease may help understanding of disease pathogenesis. Thus, APP mutations(A673T, A673 V, E682 K, E693 G, and E693Q) were transiently co-transfected into human embryonic kidney cells. Western blot assay was used to detect expression levels of APP, beta-secretase 1, and presenilin 1 in cells. Enzyme-linked immunosorbent assay was performed to determine Aβ_(1–40) and Aβ_(1–42) levels. Liquid chromatography-tandem mass chromatography was used to examine VVIAT, FLF, ITL, VIV, IAT, VIT, TVI, and VVIA peptide levels. Immunofluorescence staining was performed to measure APP and early endosome antigen 1 immunoreactivity. Our results show that the protective A673 T mutation decreases Aβ_(42)/Aβ_(40) rate by downregulating IAT and upregulating VVIA levels. Pathogenic A673 V, E682 K, and E693 Q mutations promote Aβ_(42)/Aβ_(40) rate by increasing levels of CTF99, Aβ_(42), Aβ_(40), and IAT, and decreasing VVIA levels. Pathogenic E693 G mutation shows no significant change in Aβ_(42)/Aβ_(40) ratio because of inhibition of γ-secretase activity. APP mutations can change location from the cell surface to early endosomes. Our findings confirm that certain APP mutations accelerate Aβ generation by affecting the long Aβ cleavage pathway and increasing Aβ_(42/40) rate, thereby resulting in Alzheimer's disease.

Key gene and protein changes in the beta-amyloid pathway following Longyanshen polysaccharides treatment in a mouse model of Alzheimer's disease

BACKGROUND： During onset and development of Alzheimer＇s disease, β-amyloid （Aβ） precursor protein （APP）, β-site amyloid precursor protein cleaving enzyme （BACE）, and β-amyloid are key genes and proteins in the Aβ pathway, and over-expression of these genes can lead to Aβ deposit/on in the brain. OBJECTIVE： To observe the influence of Longyanshen polysaccharides on expression of BACE, APP, and Aβ in the senescence-accelerated mouse prone/8 （SAMP8） brain, and to compare these effects with huperzine A treatment. DESIGN, TIME AND SETTING： A randomized, controlled, neurobiochemical experiment was performed at the Department of Pharmacology and Scientific Experimental Center of Guangxi Medical University from September 2005 to January 2008. MATERIALS： Longyanshen polysaccharfdes powder was extracted from the dried slices of the medicinal plant Longyanshen. The active component, Longyanshen polysaccharides, was provided by the Department of Pharmacology, Guangxi Medical University; huperzine A was purchased from Yuzhong Drug Manufactory, China. METHODS： Healthy SAMP8 mice were used to establish a model of Alzheimer＇s disease. A total of 50 SAMP8 mice were randomly assigned to 5 groups （n = 10）： SAMP8, huperzine A, low-, middle-, and high-dose polysaccharides. In addition, 10 senescence-accelerated mouse resistant 1 （SAMR1） mice were selected as normal controls. SAMP8 and SAMR1 mice were administered 30 mL/kg normal saline; the huperzine A group was administered 0.02 mg/kg huperzine A; the low-, middle-, and high-dose polysaccharides groups were respectively administered 45, 90, and 180 mg/kg Longyanshen polysaccharides. Each group was treated by intragastric administration, once per day, for 50 consecutive days. MAIN OUTCOME MEASURES： One hour after the final administration, immunohistochemical analysis was used to determine Aβ expression in the cortex and hippocampus of SAMP8 mice. Reverse-transcription polymerase chain reaction was used to determine mRNA levels of BACE and APP in SAMP8 brain tissue. RESULTS： Compared with the SAMR1 group, Aβ expression in the cerebral cortex and hippocampus, as well as expression of BACE, APP mRNA in the brain was significantly increased in the SAMP8 group （P 〈 0.05-0.01）. Compared with the SAMP8 group, Aβ expression, as well as BACE and APP mRNA expression, were significantly decreased in the cerebral cortex and hippocampus of huperzine A and low-, middle-, and high-dose polysaccharides groups （P 〈 0.05-0.01）. In particular, the effect of high-dose polysaccharides was the most significant （P 〈 0.05-0.01 ）. CONCLUSION： Longyanshen polysaccharides reduced or inhibited over-expression of BACE, APP, and Aβ in SAMP8 mice in a dose-dependent manner, and the effect was not worse than huperzine A.

<i>Ratanasampil</i>(Tibetan Medicine, RNSP) Reduces <i>β</i>-Amyloid Protein (Aβ) and Pro-Inflammatory Factor Levels and Improves Cognitive Functions in Mild-to-Moderate Alzheimer’s Disease (AD) Patients Living at High Altitude

Ratanasampil (RNSP) is a traditional Tibetan medicine used for the treatment of stroke and cerebrovascular diseases. Previous discoveries that RNSP can reduce β-amyloid protein levels and increase learning and memory in Alzheimer’s mouse models (Tg2576) led us to investigate whether RNSP can improve cognitive functions in Alzheimer’s patients. In this study, 146 AD patients living in Qinghai province received either one gram or 0.33 gram daily of RNSP for 16 weeks. Placebo patients received Piracetam. Serum Aβ40 and Aβ42 levels were measured at the beginning of the study and after 4 and 16 weeks of treatment. Compared to the same group before treatment, MMSE scores, ADAS-cog scores and ADL scores were significantly improved (p 0.05, p > 0.05). After 16-week treatment, serum TNF-α, IL-1β, IL-6 and Aβ42 levels were significantly decreased (p < 0. 01) in the high-dose RNSP group, whereas no significant differences were found in the low-dose and placebo groups. The Aβ42/Aβ40 ratio was significantly decreased after 4-week and 16-week treatment in the high-dose RNSP group (p < 0. 05, p < 0.01). Furthermore, serum Aβ42 concentrations had a strong positive correlation with TNF-α, IL-1β and IL-6 levels. There were no observable adverse effects in either treatment or control groups. We conclude that further clinical trials of RNSP in Alzheimer disease are warranted.

Humanin蛋白在Alzheimer’s病模型中神经保护作用的研究进展

研究表明,Humanin蛋白通过多种方式在抗Alzheimer’s病的过程中发挥神经保护作用。本综述从Humanin的发现、结构特征、神经保护的机制及其新型同源分泌肽Rattin的结构与功能方面介绍Humanin蛋白在Alzheimer’s病中神经保护作用的最新研究进展。

Calycosin improves cognitive function in a transgenic mouse model of Alzheimer's disease by activating the protein kinase C pathway

The major pathological changes in Alzheimer＇s disease are beta amyloid deposits and cognitive impairment. Calycosin is a typical phy- toestrogen derived from radix astragali that binds to estrogen receptors to produce estrogen-like effects. Radix astragali Calycosin has been shown to relieve cognitive impairment induced by diabetes mellitus, suggesting calycosin may improve the cognitive function of Alzhei- mer＇s disease patients. The protein kinase C pathway is upstream of the mitogen-activated protein kinase pathway and exerts a neuropro- tective effect by regulating Alzheimer＇s disease-related beta amyloid degradation. We hypothesized that calycosin improves the cognitive function of a transgenic mouse model of Alzheimer＇s disease by activating the protein kinase C pathway. Various doses of calycosin （10, 20 and 40 mg/kg） were intraperitoneally injected into APP/PS1 transgenic mice that model Alzheimer＇s disease. Calycosin diminished hippocampal beta amyloid, Tau protein, interleukin-lbeta, tumor necrosis factor-alpha, acetylcholinesterase and malondialdehyde levels in a dose-dependent manner, and increased acetylcholine and glutathione activities. The administration of a protein kinase C inhibitor, cal- phostin C, abolished the neuroprotective effects of calycosin including improving cognitive ability, and anti-oxidative and anti-inflammato- ry effects. Our data demonstrated that calycosin mitigated oxidative stress and inflammatory responses in the hippocampus of Alzheimer＇s disease model mice by activating the protein kinase C pathway, and thereby improving cognitive function.

阿尔茨海默病(Alzheimer’s Disease,AD)与动力相关蛋白1(dynamin-related protein 1,Drp1)

阿尔茨海默病(AD)已成为威胁老年人生活的一种常见病,对老年人的生活质量有着严重的影响,目前尚无有效地防治方法。最新研究发现在阿尔茨海默病的病理发生中,神经细胞伴有显著的线粒体代谢紊乱和动态变化的异常,其中动力相关蛋白1(Drp1)是参与线粒体动态变化的关键分子。深入研究阿尔茨海默病中线粒体动态变化的异常及Drp1等关键分子的作用机制,对于揭示AD的发生机制及寻找药物作用靶点具有重要意义。综述了Drp1在阿尔茨海默病中的调控机制。

Compound Danshen tablets downregulate amyloid protein precursor mRNA expression in a transgenic cell model of Alzheimer's disease Effects and a comparison with donepezil

After gene mutation, the pcDNA3.1/APP595/596 plasmid was transfected into HEK293 cells to establish a cell model of Alzheimer＇s disease. The cell model was treated with donepezil or compound Danshen tablets after culture for 72 hours. Reverse transcription-PCR showed that the mRNA expression of amyloid protein precursor decreased in all groups following culture for 24 hours, and that there was no significant difference in the amount of decrease between donepezil and compound Danshen tablets. Our results suggest that compound Danshen tablets can reduce expression of the mRNA for amyloid protein precursor in a transgenic cell model of Alzheimer＇s disease, with similar effects to donepezil.

Genistein protects hippocampal neurons against injury by regulating calcium/calmodulin dependent protein kinase Ⅳ protein levels in Alzheimer's disease model rats

Genistein has a neuroprotective effect in Alzheimer＇s disease, but its mechanism of action needs further clarification. Accumulating evidence suggests that excessive phosphorylation of tau protein causes production of neurofibrillary tangles, which is one of the main pathological characteristics of Alzheimer＇s disease, and tau protein can be phosphorylated by calcium/calmodulin dependent protein kinase IV （CAMK4）. After 7 days of pre-administration of genistein （90 mg/kg）, an Alzheimer＇s disease rat model was established using an intraperitoneal injection of D-galactose combined with an intracerebral injection of amyloid-β peptide （25-35）. The rat was then continu- ously administered genistein （90 mg/kg） for 42 days. The Morris water maze test, western blotting and hematoxylin-eosin staining results showed that genistein significantly decreased the escape latency and increased the number of times crossing the platform, reduced p-tau, CALM, CAMKK1 and p-CAMK4 protein levels in the hippocampus, and alleviated hippocampal neuron damage. These findings indicate that genistein may play a neuroprotective role in Alzheimer＇s disease through regulating CAMK4 to modulate tau hyperphosphorylation. Key

Natural polyphenols effects on protein aggregates in Alzheimer＇s and Parkinson＇s prion-like diseases

Alzheimer＇s and Parkinson＇s diseases are the most common neurodegenerative diseases. They are characterized by protein aggregates and so can be considered as prion-like disease. The major components of these deposits are amyloid peptide and tau for Alzheimer＇s disease, α-synuclein and synphilin-1 for Parkinson＇s disease. Drugs currently proposed to treat these pathologies do not prevent neurodegenerative processes and are mainly symptomatic therapies. Molecules inducing inhibition of aggregation or disaggregation of these proteins could have beneficial effects, especially if they have other beneficial effects for these diseases. Thus, several natural polyphenols, which have antioxidative, anti-inflammatory and neuroprotective properties, have been largely studied, for their effects on protein aggregates found in these diseases, notably in vitro. In this article, we propose to review the significant papers concerning the role of polyphenols on aggregation and disaggregation of amyloid peptide, tau, α-synuclein, synphilin-1, suggesting that these compounds could be useful in the treatments in Alzheimer＇s and Parkinson＇s diseases.

BACE1 inhibitors:A promising therapeutic approach for the management of Alzheimer’s disease

Alzheimer’s disease is a neurological disorder marked by the accumulation of amyloid beta(Aβ)aggregates,resulting from mutations in the amyloid precursor protein.The enzymeβ-secretase,also known asβ-site amyloid precursor protein cleaving enzyme 1(BACE1),plays a crucial role in generating Aβpeptides.With no targeted therapy available for Alzheimer’s disease,inhibiting BACE1 aspartic protease has emerged as a primary treatment target.Since 1999,compounds demonstrating potential binding to the BACE1 receptor have advanced to human trials.Structural optimization of synthetically derived compounds,coupled with computational approaches,has offered valuable insights for developing highly selective leads with drug-like properties.This review highlights pivotal studies on the design and development of BACE1 inhibitors as anti-Alzheimer’s disease agents.It summarizes computational methods employed in facilitating drug discovery for potential BACE1 inhibitors and provides an update on their clinical status,indicating future directions for novel BACE1 inhibitors.The promising clinical results of Elenbecestat(E-2609)catalyze the development of effective,selective BACE1 inhibitors in the future.

Multifaceted neuroprotective effects of(-)-epigallocatechin-3-gallate(EGCG)in Alzheimer's disease:an overview of pre-clinical studies focused onβ-amyloid peptide

Alzheimer’s disease(AD)is the most common neurodegenerative disease characterized by cognitive decline and memory impairment.Many lines of evidence indicate that excessiveβ-amyloid peptide(Aβ)generation and aggregation play pivotal roles in the initiation of AD,leading to various biochemical alteration including oxidative damage,mitochondrial dysfunction,neuroinflammation,signaling pathway and finally resulting in neuronal death.AD has a complex pathogenic mechanism,and a single-target approach for anti-AD strategy is thus full of challenges.To overcome these limitations,the present study focused to review on one of multiple target-compounds,(-)-epigallocatechin-3-gallate(EGCG)for the prevention and treatment of AD.EGCG is a main bioactive polyphenol in green tea and has been reported to exert potent neuroprotective properties in a wide array of both cellular and animal models in AD.This review demonstrated multiple neuroprotective efficacies of EGCG by focusing on the involvement of Aβ-evoked damage and its Aβregulation.Furthermore,to understand its mechanism of action on the brain,the permeability of the blood-brain barrier was also discussed.

Neurofibrillary tangles in Alzheimer＇s disease： elucidation of the molecular mechanism by immunohistochemistry and tau protein phospho-proteomics

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.

Mesenchymal stem cells:As a multi-target cell therapy for clearingβ-amyloid deposition in Alzheimer’s disease

Extracellularβ-amyloid(Aβ)plaques and neurofibrillary tangles(NFTs)are the pathological hallmarks of Alzheimer’s disease(AD).Studies have shown that aggregates of extracellular Aβcan induce neuroinflammation mediated neurotoxic signaling through microglial activation and release of pro-inflammatory factors.Thus,modulation of Aβmight be a potential therapeutic strategy for modifying disease progression.Recently,a large number of reports have confirmed the beneficial effects of mesenchymal stem cells(MSCs)on AD.It is believed to reduce neuroinflammation,reduce Aβamyloid deposits and NFTs,increase acetylcholine levels,promote neurogenesis,reduce neuronal damage,and improve working memory and cognition.In this review,we focus on the role of MSCs in clearing Aβdeposition.MSCs have the potential to modulate Aβ-related microenvironments via enhancement of autophagy,proteolysis of Aβaggregates,phagocytic clearance of Aβby microglial M2 polarization,decrease oxidative stress(OS),and correction of abnormal sphingolipid(SL)metabolism.With advantages in clinical applications,these data suggest that the use of MSCs as a multi-target modulator of Aβwould be an effective therapeutic approach in AD.

Role of Microtubule-associated Protein Tau Phosphorylation in Alzheimer's Disease

As a major microtubule-associated protein, tau plays an important role in promoting microtubule assembly and stabilizing microtubules. In Alzheimer’s disease(AD) and other tauopathies, the abnormally hyperphosphorylated tau proteins are aggregated into paired helical filaments and accumulated in the neurons with the form of neurofibrillary tangles. An imbalanced regulation in protein kinases and protein phosphatases is the direct cause of tau hyperphosphorylation. Among various kinases and phosphatases, glycogen synthase kinase-3β(GSK-3β) and protein phosphatase 2A(PP2A) are the most implicated. Accumulation of the hyperphosphorylated tau induces synaptic toxicity and cognitive impairments. Here, we review the upstream factors or pathways that can regulate GSK-3β or PP2A activity mainly based on our recent findings. We will also discuss the mechanisms that may underlie tau-induced synaptic toxicity.

Transthyretin—A Key Gene Involved in Regulating Learning and Memory in Brain, and Providing Neuroprotection in Alzheimer Disease via Neuronal Synthesis of Transthyretin Protein

Transthyretin (TTR), a carrier protein present in the liver and choroid plexus of the brain, has been shown to be responsible for binding thyroid hormone thyroxin (T4) and retinol in plasma and cerebrospinal fluid (CSF). TTR aids in sequestering of beta-amyloid peptides Aβ deposition, and protects the brain from trauma, ischemic stroke and Alzheimer disease (AD). Accordingly, hippocampal gene expression of TTR plays a significant role in learning and memory as well as in simulation of spatial memory tasks. TTR via interacting with transcription factor CREB regulates this process and decreased expression leads to memory deficits. By different signaling pathways, like MAPK, AKT, and ERK via Src, TTR provides tropical support through megalin receptor by promoting neurite outgrowth and protecting the neurons from traumatic brain injury. TTR is also responsible for the transient rise in intracellular Ca2+ via NMDA receptor, playing a dominant role under excitotoxic conditions. In this review, we tried to shed light on how TTR is involved in maintaining normal cognitive processes, its role in learning and memory, under memory deficit conditions;by which mechanisms it promotes neurite outgrowth;and how it protects the brain from Alzheimer disease (AD).

Two memory associated genes regulated by amyloid precursor protein intracellular domain Novel insights into the pathogenesis of learning and memory impairment in Alzheimer's disease

In this study, we employed chromatin immunoprecipitation, a useful method for studying the locations of transcription factors bound to specific DNA regions in specific cells, to investigate amyloid precursor protein intracellular domain binding sites in chromatin DNA from hippocampal neurons of rats, and to screen out five putative genes associated with the learning and memory functions. The promoter regions of the calcium/calmodulin-dependent protein kinase II alpha and glutamate receptor-2 genes were amplified by PCR from DNA products immunoprecipitated by amyloid precursor protein intracellular domain. An electrophoretic mobility shift assay and western blot analysis suggested that the promoter regions of these two genes associated with learning and memory were bound by amyloid precursor protein intracellular domain （in complex form）. Our experimental findings indicate that the amyloid precursor protein intracellular domain is involved in the transcriptional regulation of learning- and memory-associated genes in hippocampal neurons. These data may provide new insights into the molecular mechanism underlying the symptoms of progressive memory loss in Alzheimer＇s disease.

Correlation between prion protein gene codon 129 polymorphism and late-onset Alzheimer's disease

BACKGROUND： Studies addressing the correlation between prion protein gene codon 129 polymorphism, Alzheimer＇s disease, and cognitive disorders have mainly focused on Caucasians. However, prion protein gene codon 129 polymorphism is thought to also affect the Chinese Han and Wei populations. OBJECTIVE： To analyze the differences of prion protein gene codon 129 distribution among the elderly Chinese Han, East Asian, and Caucasian populations, and to study the correlation between prion protein gene codon 129 distribution and late-onset Alzheimer＇s disease. DESIGN, TIME AND SETTING： A gene polymorphism analysis was performed in the Institute of Geriatrics, General Hospital of Chinese PLA between January 2006 and January 2007. PARTICIPANTS： A total of 152 elderly Chinese Han people were selected from the Beijing Troop Cadre＇s Sanitarium. Among them, 60 patients with late-onset Alzheimer＇s disease, with a mean age of （82 ± 7） years （range 67-94 years） and disease course of （5.9 ± 4.4） years, comprising 44 males with a mean age of （83 ± 7） years and 16 females with a mean age of （78 ±7） years, were selected for the case group. An additional 92 healthy elderly subjects, with a mean of （76 ± 9） years （range 60-94 years）, comprising 76 males with a mean age of （77 ± 9） years and 16 females with a mean age of （70 ± 8） years, were selected for the control group. There were no significant differences in age and gender between the two groups （P〉 0.05）. METHODS： DNA was extracted from peripheral blood leukocytes using routine phenol/chloroform methodology. Prion protein gene codon 129 potymorphism and ApoE polymorphism were measured using PCR-restriction fragment length polymorphism. The ApoEε allele was considered the standard for analyzing correlations between prion protein gene codon 129 polymorphism and late-onset Alzheimer＇s disease. MAIN OUTCOME MEASURES： Prion protein gene codon 129 distribution; correlation between genotypic frequency and allele frequency of prion protein gene codon 129 with Alzheimer＇s disease; relationship between methionine/methionine genotype of priori protein gene, ApoEε4 allele, gender, and age of Alzheimer＇s disease patients. RESULTS： Methionine/methionine genotypic frequency of prion protein gene codon 129 was 94.08% in the Chinese elderly population, and the methionine/valine genotypic frequency was 5.92%. However, valine/valine homozygotes were not determined. There was no significant difference in prion protein gene codon 129 polymorphism between the Chinese elderly and East Asian populations （P〉 0.05）. However, there was a significant difference between the Chinese elderly and the Caucasian population （P 〈 0.05）. The methionine/methionine genotype for the positive and negative ApoEε4 alleles was a risk factor for increased incidence of Alzheimer＇s disease, but there was no significant difference between the positives and the negatives （odds ratio = 1.33, 95% confidence interval = 0.32-6.49, P〉 0.05）. CONCLUSION： Prion protein gene codon 129 distribution in the Chinese elderly was different from the Caucasian population, which suggested that the methionine/methionine genotype of prion protein gene codon 129 negatively correlated with late-onset Alzheimer＇s disease.

AAV mediated carboxyl terminus of Hsp70 interacting protein overexpression mitigates the cognitive and pathological phenotypes of APP/PS1 mice

The E3 ubiquitin ligase,carboxyl terminus of heat shock protein 70(Hsp70)interacting protein(CHIP),also functions as a co-chaperone and plays a crucial role in the protein quality control system.In this study,we aimed to investigate the neuroprotective effect of overexpressed CHIP on Alzheimer’s disease.We used an adeno-associated virus vector that can cross the blood-brain barrier to mediate CHIP overexpression in APP/PS1 mouse brain.CHIP overexpression significantly ameliorated the performance of APP/PS1 mice in the Morris water maze and nest building tests,reduced amyloid-βplaques,and decreased the expression of both amyloid-βand phosphorylated tau.CHIP also alleviated the concentration of microglia and astrocytes around plaques.In APP/PS1 mice of a younger age,CHIP overexpression promoted an increase in ADAM10 expression and inhibitedβ-site APP cleaving enzyme 1,insulin degrading enzyme,and neprilysin expression.Levels of HSP70 and HSP40,which have functional relevance to CHIP,were also increased.Single nuclei transcriptome sequencing in the hippocampus of CHIP overexpressed mice showed that the lysosomal pathway and oligodendrocyte-related biological processes were up-regulated,which may also reflect a potential mechanism for the neuroprotective effect of CHIP.Our research shows that CHIP effectively reduces the behavior and pathological manifestations of APP/PS1 mice.Indeed,overexpression of CHIP could be a beneficial approach for the treatment of Alzheimer’s disease.