Genetic and epigenetic targets of natural dietary compounds as anti-Alzheimer's agents

Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older adults.Pathogenic factors,such as oxidative stress,an increase in acetylcholinesterase activity,mitochondrial dysfunction,genotoxicity,and neuroinflammation are present in this syndrome,which leads to neurodegeneration.Neurodegenerative pathologies such as Alzheimer’s disease are considered late-onset diseases caused by the complex combination of genetic,epigenetic,and environmental factors.There are two main types of Alzheimer’s disease,known as familial Alzheimer’s disease(onset<65 years)and late-onset or sporadic Alzheimer’s disease(onset≥65 years).Patients with familial Alzheimer’s disease inherit the disease due to rare mutations on the amyloid precursor protein(APP),presenilin 1 and 2(PSEN1 and PSEN2)genes in an autosomaldominantly fashion with closely 100%penetrance.In contrast,a different picture seems to emerge for sporadic Alzheimer’s disease,which exhibits numerous non-Mendelian anomalies suggesting an epigenetic component in its etiology.Importantly,the fundamental pathophysiological mechanisms driving Alzheimer’s disease are interfaced with epigenetic dysregulation.However,the dynamic nature of epigenetics seems to open up new avenues and hope in regenerative neurogenesis to improve brain repair in Alzheimer’s disease or following injury or stroke in humans.In recent years,there has been an increase in interest in using natural products for the treatment of neurodegenerative illnesses such as Alzheimer’s disease.Through epigenetic mechanisms,such as DNA methylation,non-coding RNAs,histone modification,and chromatin conformation regulation,natural compounds appear to exert neuroprotective effects.While we do not purport to cover every in this work,we do attempt to illustrate how various phytochemical compounds regulate the epigenetic effects of a few Alzheimer’s disease-related genes.

Loss of canonical Wnt signaling is involved in the pathogenesis of Alzheimer's disease

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.

Nanotechnology-based gene therapy as a credible tool in the treatment of Alzheimer’s disease

Toxic aggregated amyloid-βaccumulation is a key pathogenic event in Alzheimer’s disease.Treatment approaches have focused on the suppression,deferral,or dispersion of amyloid-βfibers and plaques.Gene therapy has evolved as a potential therapeutic option for treating Alzheimer’s disease,owing to its rapid advancement over the recent decade.Small interfering ribonucleic acid has recently garnered considerable attention in gene therapy owing to its ability to down-regulate genes with high sequence specificity and an almost limitless number of therapeutic targets,including those that were once considered undruggable.However,lackluster cellular uptake and the destabilization of small interfering ribonucleic acid in its biological environment restrict its therapeutic application,necessitating the development of a vector that can safeguard the genetic material from early destruction within the bloodstream while effectively delivering therapeutic genes across the bloodbrain barrier.Nanotechnology has emerged as a possible solution,and several delivery systems utilizing nanoparticles have been shown to bypass key challenges regarding small interfering ribonucleic acid delivery.By reducing the enzymatic breakdown of genetic components,nanomaterials as gene carriers have considerably enhanced the efficiency of gene therapy.Liposomes,polymeric nanoparticles,magnetic nanoparticles,dendrimers,and micelles are examples of nanocarriers that have been designed,and each has its own set of features.Furthermore,recent advances in the specific delivery of neurotrophic compounds via gene therapy have provided promising results in relation to augmenting cognitive abilities.In this paper,we highlight the use of different nanocarriers in targeted gene delivery and small interfering ribonucleic acid-mediated gene silencing as a potential platform for treating Alzheimer’s disease.

Analysis of hippocampal gene expression profile of Alzheimer's disease model rats using genome chip bioinformatics

In this study, an Alzheimer＇s disease model was established in rats through stereotactic injection of condensed amyloid beta 1-40 into the bilateral hippocampus, and the changes of gene expression profile in the hippocampus of rat models and sham-operated rats were compared by genome expression profiling analysis. Results showed that the expression of 50 genes was significantly up-regulated （fold change 〉 2）, while 21 genes were significantly down-regulated in the hippocampus of Alzheimer＇s disease model rats （fold change 〈 0.5） compared with the sham-operation group. The differentially expressed genes are involved in many functions, such as brain nerve system development, neuronal differentiation and functional regulation, cellular growth, differentiation and apoptosis, synaptogenesis and plasticity, inflammatory and immune responses, ion channels/transporters, signal transduction, cell material/energy metabolism. Our findings indicate that several genes were abnormally expressed in the metabolic and signal transduction pathways in the hippocampus of amyloid beta 1 40-induced rat model of Alzheimer＇s disease, thereby affecting the hippocampal and brain functions.

Effects of Small Interfering RNATargeting Sphingosine Kinase-1 Gene on the Animal Model of Alzheimer's Disease

Summary： Alzheimer＇s disease （AD） is an age-related, progressive neurodegenerative disorder that occurs gradually and results in memory, behavior, and personality changes. Abnormal sphingolipid metabolism was reported in AD previously. This study aimed to investigate whether sphK1 could exacerbate the accumulation of amyloid protein （Aβ） and sharpen the learning and memory ability of the animal model of AD using siRNA interference. An adenovirus vector expressing small interfering RNA （siRNA） against the sphK1 gene （sphKl-siRNA） was designed, and the effects of sphKl-siRNA on the APP/PS1 mouse four weeks after treatment with sphKl-siRNA hippocampal injection were examined. SphK1 protein expression was confirmed by using Western blotting and ceramide content coupled with SIP secretion was evaluated by enzyme-linked immunosorbent assay （ELISA）. Aβ load was detected by immunohistochemical staining and ELISA. Morris water maze was adopted to test the learning and memory ability of the APP/PS 1 mice. A significant difference in the expression of sphK1 protein and mRNA was observed between the siRNA group and the control group. Aβ load in transfected mice was accelerated in vivo, with significant aggravation of the learn- ing and memory ability. The sphKl gene modulation in the All load and the learning and memory ability in the animal model of AD may be important for the treatment of AD.

Northern Chinese Han populations with sporadic Alzheimer’s disease and the role of urokinase-type plasminogen activator gene promoter polymorphisms

BACKGROUND; Polymorphisms of urokinase-type plasminogen activator gene （PLAU） have recently been reported to be associated with sporadic Alzheimer＇ disease （SAD）. However, most studies have focused on the exon region of this gene, and there is no report on the association between promoter polymorphisms of the PLAU and SAD. OBJECTIVE： To determine whether SAD is associated with promoter polymorphisms of PLAU in Northem Han Chinese. DESIGN, TIME AND SETTING： A case-control study was performed at Neurology Laboratory of Xuanwu Hospital of the Capital Medical University from September 2006 to July 2008. PARTICIPANTS： A total of 397 participants living in Beijing were assigned to SAD [n = 196, including 103 males and 93 females, mean age of （64 ± 7） years] and control [n = 201, including 108 males and 93 females, mean age of （68 ± 6） years] groups. The patients were diagnosed and met the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer＇s Disease and Related Disorder Association criteria for possible Alzheimer＇s disease. Controls received clinical, mental, and neurological examinations to rule out cognitive deficiencies. All controls had Mini-Mental Status Examination scores 〉 27. METHODS： Genotypes of PLAU and apolipoprotein-E were examined in 196 patients with SAD and 201 age- and sex-matched controls from the same community using polymerase chain reaction-restriction fragment length polymorphism method. SPSS 11.5 software was used for data analysis, distribution of allele and genotypic frequency were calculated, and Hardy-Weinberg was also performed in this study. MAIN OUTCOME MEASURES： The main outcome measures were allele and genotype frequency differences in the promoter region of the PLAU gene between SAD and control subjects. RESULTS： In Chinese Han populations, the two polymorphisms in PLAU promoter were -25 C/T （rs2227579） and 43 G/T （rs2227580）. Detection of these promoter polymorphisms revealed significant differences in allele and genotype frequency for -25 CfT and 43 G/T when 196 SAD patients were compared with 201 controls （P〈 0.05）. Logistic analyses indicated that, compared with C/T and T/T genotypes, the -25 C/C genotype resulted in a 1.5-fold risk for developing SAD （adjusted odds ratio = 1.510, 95% confidence interval： 0.198 2.281, P= 0.010）, while the 43G/G genotype resulted in a 1.3-fold risk for SAD （adjusted odds ratio = 1.300, 95% confidence interval： 0.178 2.051, P= 0.030）. CONCLUSION： The present study provided evidence that promoter polymorphisms of PLAU are associated with development of SAD in Northern Han Chinese.

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.

Hybrid Feature Selection Method for Predicting Alzheimer’s Disease Using Gene Expression Data

Gene expression(GE)classification is a research trend as it has been used to diagnose and prognosis many diseases.Employing machine learning(ML)in the prediction of many diseases based on GE data has been a flourishing research area.However,some diseases,like Alzheimer’s disease(AD),have not received considerable attention,probably owing to data scarcity obstacles.In this work,we shed light on the prediction of AD from GE data accurately using ML.Our approach consists of four phases:preprocessing,gene selection(GS),classification,and performance validation.In the preprocessing phase,gene columns are preprocessed identically.In the GS phase,a hybrid filtering method and embedded method are used.In the classification phase,three ML models are implemented using the bare minimum of the chosen genes obtained from the previous phase.The final phase is to validate the performance of these classifiers using different metrics.The crux of this article is to select the most informative genes from the hybrid method,and the best ML technique to predict AD using this minimal set of genes.Five different datasets are used to achieve our goal.We predict AD with impressive values forMultiLayer Perceptron(MLP)classifier which has the best performance metrics in four datasets,and the Support Vector Machine(SVM)achieves the highest performance values in only one dataset.We assessed the classifiers using sevenmetrics;and received impressive results,allowing for a credible performance rating.The metrics values we obtain in our study lie in the range[.97,.99]for the accuracy(Acc),[.97,.99]for F1-score,[.94,.98]for kappa index,[.97,.99]for area under curve(AUC),[.95,1]for precision,[.98,.99]for sensitivity(recall),and[.98,1]for specificity.With these results,the proposed approach outperforms recent interesting results.With these results,the proposed approach outperforms recent interesting results.

Presymptomatic Diagnosis and Gene Therapy for Alzheimer’s Disease: Genomic, Therapeutic, and Ethical Aspects—A Systematic Review

Over the past three decades, genomic and epigenetic sciences have identified more than 70 genes involved in the molecular pathophysiology of Alzheimer’s disease (AD). DNA methylation, abnormal histone and chromatin regulation and the action of various miRNAs induce AD. The identification of mutated genes has paved the way for the development of diagnostic kits and the initiation of gene therapy trials. However, despite major advances in neuroscience research, there is yet no suitable treatment for AD. Therefore, the early diagnosis of this neurodegenerative disease raises several ethical questions, including the balance between the principle of non-maleficence and the principle of beneficence. The aims of this research were to present the genomic and ethical aspects of AD, and to highlight the ethical principles involved in its presymptomatic diagnosis and therapy. A systematic review of the literature in PubMed, Google Scholar and Science Direct was carried out to outline the genomic aspects and ethical principles relating not only to the presymptomatic diagnosis of AD, but also to its gene therapy. A total of 16 publications were selected. AD is a multifactorial disease that can be genetically classified into Sporadic Alzheimer’s Disease and Familial Alzheimer’s Disease based on family history. Gene therapy targeting specific disease-causing genes is a promising therapeutic strategy. Advancements in artificial intelligence applications may enable the prediction of AD onset several years in advance. While early diagnosis of AD may empower patients with full decision competence for early decision-making, it also carries implications for the patient’s family members, who are at risk of developing the disease, potentially becoming a source of confusion or anxiety. AD has a significant impact on the life of individuals at risk and their families. Given the absence of disease modifying therapy, genetic screening and early diagnosis for this condition raise ethical issues that must be carefully considered in the context of fundamental bioethical principles, including autonomy, beneficence, non-maleficence, and justice.

Association of ACE Gene with Metabolic Syndrome, Hypertension and Alzheimer Disease by RFLP-PCR

ACE gene is associated with multifactorial diseases:metabolic syndrome,obesity,diabetes mellitus,hypertension,stroke,myocardial infarction,ageing,Alzheimer disease,acute pulmonary failure and COVID-19 infections.The purpose of this study is to test the association between the II,ID and DD polymorphisms of angiotensin-converting enzyme(ACE)gene,and metabolic syndrome,hypertension(HBP)and Alzheimer disease(AD),based on clinical data and biochemical laboratory investigations conducted on inpatients,applying the RFLP-PCR technique.The genotyping of ACE gene was carried out by RFLP-PCR on the basis of DNA isolated from total blood in 144 subjects selected at Giurgiu County Emergency Hospital.The results were statistically processed by the Hardy-Weinberg equilibrium,Odds Ratio,VMD,StatsDirect and PyElph software.The II,ID and DD polymorphisms of ACE gene identified by the RFLP-PCR present a high risk of developing the metabolic syndrome in the MS,hypertension and Alzheimer disease groups.

Fuzzy Cluster Analysis of Alzheimer’s Disease-Related Gene Sequences

The objective of this paper is to analyze the relationship among the interrelated gene sequences of Alzheimer’s disease (AD). Further this paper will provide a study on genetic factor of the occurrence about Alzheimer’s disease, so as to provide more information on the prevention of Alzheimer’s disease, the clinical diagnosis and gene therapy for Alzheimer’s disease. The respective alignment of the Alzheimer’s disease interrelated gene sequences with those in The National Center for Biotechnology Information (NCBI) database was studied, and the measurement relationship of these sequences was identified and analyzed by the method of fuzzy cluster. The result of fuzzy cluster analysis indicates that the gene sequences interrelated within one group is consistently having closer relationship within the group other than in another group.

BLMH and APOE genes in Alzheimer Disease: A possible relation

Alzheimer disease (AD) is a progressive and irreversible neurodegenerative disorder that is characterized by cognitive decline, memory loss and confusion. The E4 allele of the apolipoprotein E gene (APOE) is associated with AD and it is the main genetic risk factor for disease. Although the exact physiological function is unknown, bleomycin hydrolase (BLMH) may also be associated with AD development, although previous immunohistochemical findings havebeen inconsistent. Therefore, the purpose ofthis study was to evaluate the genotypic and allele frequencies of theAPOEgene andBLMH1450 G> A polymorphism and assessBLMHexpression using PCR-RFLP and RT-qPCR analyses ofblood samples from patients with Alzheimer disease (AD), healthy elderly adults (EC) andhealthyyoung subjects(YC). BLMHexpression wassignificantly different among groups (p= 0.015) and there was substantial reduction with age and with AD. TheAPOEandBLMHgenotype frequency did not diverge from the Hardy-Weinberg equilibrium. There was a higher frequency of genotype 3/3 inall subjects (61.1%) and the AD group demonstrated a higher frequency of allele 4;however, differences ingenotype and allele distributions were statistically different among groups.

Characteristics and advantages of adeno-associated virus vector-mediated gene therapy for neurodegenerative diseases

Common neurodegenerative diseases of the central nervous system are characterized by progressive damage to the function of neurons, even leading to the permanent loss of function. Gene therapy via gene replacement or gene correction provides the potential for transformative therapies to delay or possibly stop further progression of the neurodegenerative disease in affected patients. Adeno-associated virus has been the vector of choice in recent clinical trials of therapies for neurodegenerative diseases due to its safety and efficiency in mediating gene transfer to the central nervous system. This review aims to discuss and summarize the progress and clinical applications of adeno-associated virus in neurodegenerative disease in central nervous system. Results from some clinical trials and successful cases of central neurodegenerative diseases deserve further study and exploration.

广州75岁以上老年人群LRP、α2-MG基因多态性与Alzheimer病的关系

目的了解高龄老年人群A lzheim er病(AD)患者低密度脂蛋白受体相关蛋白(LRP)和α2巨球蛋白(α2-MG)基因型的分布,探讨这两种基因多态性和AD的相关关系。方法采用系统整群抽样方法调查广州市荔湾区75岁以上的老年居民3 825例,按DSM-Ⅲ-R和NINCDS/ADRDA的诊断标准,从中筛选出无血缘关系的散发性AD患者190例(其中有部分患者接受抽血检查),并以该人群中的健康老年人作为对照。采用PCR-RFLP技术,检测以上两组老年人LRP和α2-G基因型。结果AD组LRP的C、T基因频率分别为93.8%、6.2%,对照组LRP的C、T基因频率分别为93.0%、7.0%;AD组α2-MG的A2M-1、A2M-2基因频率分别为95.7%、4.3%,对照组α2-MG的A2M-1、A2M-2基因频率分别为98.3%、1.7%。AD组与对照组在LRP或α2-MG的基因型频率及等位基因频率分布上的差异均无显著性(P>0.05)。结论广州市荔湾区75岁以上老年人群LRP和α2-MG基因可能均不是AD发病的遗传危险因素。

LRP基因多态性和BCHE-K变异与阿尔茨海默病的相关性研究

目的探讨中国汉族人低密度脂蛋白受体相关蛋白(LRP)基因多态性、丁基胆碱酯酶基因K(BCHE-K)变异与阿尔茨海默病(AD)的相关情况。方法应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)及等位基因特异-聚合酶链反应(AS-PCR)方法,观察了67例AD患者和77例正常人LRP基因和BCHE-K变异基因多态性的分布,并进行关联分析。结果AD患者LRP基因C/C纯合子基因型频率(88.1%)及等位基因C频率(94.0%)均高于对照组(P<0.05),AD患者BCHE-K变异与对照组比较均无显著性差异。结论LRP基因多态性与AD发病可能相关;BCHE-K变异与AD发病无明显相关性。

Alzheimer病和血管性痴呆患者APOE及LRP基因多态性与认知及精神行为症状相关性研究

目的探讨Alzheimer病(AD)和血管性痴呆(VD)患者APOE及LRP基因多态性与认知及精神行为症状(BPSD)的相关性。方法收集AD患者79例、VD患者85例和健康对照者(对照组)156名,采用简易精神状态检查量表(MMSE)评定认知功能;采用简明精神病量表和汉密尔顿抑郁(HAMD)、焦虑量表(HAMA)评定BPSD。采用PCR-RFLP进行APOEε、LRP基因分型。结果 (1)AD组(17.7%)及VD组(20.5%)APOEε4等位基因频率均高于对照组(5.7%,均P<0.01)。(2)AD组和VD组APOEε4携带者MMSE得分均低于同组APOEε4非携带者〔AD组(13.84±2.32)分vs.(14.78±2.54)分,P<0.01;VD组(15.53±1.87)分vs.(18.45±2.23)分,P<0.01〕。(3)AD组患者APOEε4携带者BPSD比例明显高于APOEε4非携带者(55.56%vs.52.83%,P=0.039)。结论 APOEε4可能是AD、VD患者认知障碍的共同危险因素。APOEε4可能是AD的BPSD危险因素。

MicroRNA and mRNA profiling of cerebral cortex in a transgenic mouse model of Alzheimer’s disease by RNA sequencing

In a previous study,we found that long non-coding genes in Alzheimer’s disease(AD)are a result of endogenous gene disorders caused by the recruitment of microRNA(miRNA)and mRNA,and that miR-200a-3p and other representative miRNAs can mediate cognitive impairment and thus serve as new biomarkers for AD.In this study,we investigated the abnormal expression of miRNA and mRNA and the pathogenesis of AD at the epigenetic level.To this aim,we performed RNA sequencing and an integrative analysis of the cerebral cortex of the widely used amyloid precursor protein and presenilin-1 double transgenic mouse model of AD.Overall,129 mRNAs and 68 miRNAs were aberrantly expressed.Among these,eight down-regulated miRNAs and seven up-regulated miRNAs appeared as promising noninvasive biomarkers and therapeutic targets.The main enriched signaling pathways involved mitogen-activated kinase protein,phosphatidylinositol 3-kinase-protein kinase B,mechanistic target of rapamycin kinase,forkhead box O,and autophagy.An miRNA-mRNA network between dysregulated miRNAs and corresponding target genes connected with AD progression was also constructed.These miRNAs and mRNAs are potential biomarkers and therapeutic targets for new treatment strategies,early diagnosis,and prevention of AD.The present results provide a novel perspective on the role of miRNAs and mRNAs in AD.This study was approved by the Experimental Animal Care and Use Committee of Institute of Medicinal Biotechnology of Beijing,China(approval No.IMB-201909-D6)on September 6,2019.

Protective effects of proanthocyanidins on beta-amyloid peptide (25-35)-induced PC12 cell apoptosis by blocking S-phase and increasing p53 gene expression

BACKGROUND： Current studies related to the effects of proanthocyanidins on Alzheimer＇s disease have focused primarily on the signal transduction pathway of cellular apoptosis. However, the influence of p53 gene expression on cell cycle regulation, with regard to the protective mechanisms of proanthocyanidins, has not been reported. OBJECTIVE： To observe the effect of proanthocyanidins on cell cycle distribution, cellular apoptosis and p53 gene expression in β-amyloid peptide （25-35） （Aβ25-35）-induced PC12 cells cultured in serum-free media, and to investigate the molecular neuroprotective mechanisms of proanthocyanidins with regard to cell cycle regulation. DESIGN, TIME AND SETTING： A parallel, controlled, at the Institute of Biochemistry and Molecular Biology cellular, and molecular study was performed Guangdong Medical College from July 2006 to July 2008. MATERIALS： Proanthocyanidins were provided by Nanjing Xuezi Medical and Chemical Research Center, China; Aβ25-35 was provided by Sigma, USA; PC12 cells were provided by the Institute of Basic Medical Science, Academy of Military Medical Sciences; and rabbit anti-p53 polyclonal antibody was provided by Santa Cruz Biotechnology, USA. METHODS： PC12 cells were cultured in serum-free media for 24 hours. Cells from the model group were treated with 25 μmol/L Aβ25-35 for 24 hours. Cells in the drug protection group were pre-treated with 30 mg/L proanthocyanidins for 1 hour and then treated with 25 μmol/LAβ2^-35 for 24 hours. The control group was not treated. MAIN OUTCOME MEASURES： Flow cytometry was used to detect cell cycle distribution and rate of apoptosis; reverse-transcriptase polymerase chain reaction was used to detect p53 mRNA expression; and Western blot was used to detect p53 protein expression. RESULTS： After treating with 25 μmol/LAβ25-35 for 24 hours, the rate of apoptosis and the percentage of cells in S phase were significantly increased （P 〈 0.01 ）, and p53 mRNA and protein expressions were decreased. Pretreatment with proanthocyanidins for 1 hour blocked the increase in apoptosis and the percentage of cells in S phase in Aβ25-35-induced PC12 cells （P 〈 0.01 ） and increased p53 mRNA and protein expressions. CONCLUSION： Proanthocyanidins blocked apoptosis and S-phase arrest in Aβ25-35-induced PC12 cells cultured in serum-free media. The protective mechanism could be related to increased p53 mRNA and protein expressions.

Gene expression in rat mesenchymal stem cells following treatment with natural cerebrolysin-containing serum Validation of a whole genome microarray technique

BACKGROUND： Natural cerebrolysin （NC）, a Chinese herbal drug for the treatment of Alzheimer＇s disease （AD）, induces mesenchymal stem cell （MSC） differentiation into neuron-like cells, with low toxicity. But the mechanisms involved in NC effects on MSCs remain poorly understood. OBJECTIVE： We used a whole genome microarray technique to further investigate the molecular, genetic, and pharmacodynamic mechanisms of NC on MSC gene expression profiles. DESIGN, TIME AND SETTING： A parallel, controlled, in vitro experiment was performed at the First Affiliated Hospital of Shenzhen University, Shenzhen Institute of Integrated Chinese and Western Medicine, China, between September 2006 and October 2008. MATERIALS： NC was provided by Shenzhen Institute of Integrated Chinese and Western Medicine China. It was predominantly composed of Renshen （Radix Ginseng）, Tianma （Rhizoma Gastrodiae） and Yinxingye （Ginkgo Leaf） and prepared by conventional water extractJon technology. Twelve adult, male, New Zealand rabbits were included, six of which underwent intragastric administration of NC extract for 1 month to create NC-containing serum. METHODS： Bone marrow was collected from the tibia and femur of Sprague Dawley rats, aged 6 8 months old. Rat MSCs were isolated and purified by the whole bone marrow adherence method. After in vitro culture, MSCs from passage 4 were treated with NC-containing serum for 48 hours, and total RNA was extracted. Gene expression in MSCs was analyzed using Affymetrix whole genome microarray analysis. MAIN OUTCOME MEASURES： Differentially expressed genes in NC serum-treated MSCs. RESULTS： NC treated MSCs displayed 46 differentially expressed genes, 22 with upregulated expression （fold change 〉 2） and 24 with downregulated expression （fold change 〈 -2）. Differentially expressed genes participated in neuronal growth, differentiation, and function, cell growth, differentiation, proliferation, apoptosis, signal transduction, substance/energy metabolism, ion transport, and immune responses. NC treatment changed levels of transforming growth factor β/ bone morphogenetic proteins, Hedgehog, Bmp, and Wntsignaling pathways, which regulate nerve cell differentiation, development and function, as well as learning and memory; Ras, G protein- coupled receptor signal pathways that are related to cell growth, proliferation, and apoptosis; and mitogen-activated protein kinase kinase kinase signaling cascades. CONCLUSION： NC can regulate gene expression for many signal transduction pathways related to nerve cell differentiation, development and function, learning and memory function, as well as regulation of cell growth, differentiation, proliferation, or apoptosis to mediate the genetic effects of NC treatment on AD.

AAV-based gene therapy approaches for genetic forms of tauopathies and related neurogenetic disorders

Tauopathies comprise a spectrum of genetic and sporadic neurodegenerative diseases mainly characterized by the presence of hyperphosphorylated TAU protein aggregations in neurons or glia.Gene therapy,in particular adeno-associated virus(AAV)-based,is an effective medical approach for difficult-to-treat genetic diseases for which there are no convincing traditional therapies,such as tauopathies.Employing AAV-based gene therapy to treat,in particular,genetic tauopathies has many potential therapeutic benefits,but also drawbacks which need to be addressed in order to successfully and efficiently adapt this still unconventional therapy for the various types of tauopathies.In this Viewpoint,we briefly introduce some potentially treatable tauopathies,classify them according to their etiology,and discuss the potential advantages and possible problems of AAV-based gene therapy.Finally,we outline a future vision for the application of this promising therapeutic approach for genetic and sporadic tauopathies.