Displaying publications 1 - 20 of 24 in total

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  1. A case of early-onset familial Alzheimer's disease with both APP and novel PSEN2 mutations presenting with non-amnestic features
    Chee KY, Yee OK, Gaillard F, Velakoulis D, Mohd Zain NR, Yogendren L, et al.
    Aust N Z J Psychiatry, 2017 Dec;51(12):1252-1253.
    PMID: 28762277 DOI: 10.1177/0004867417722642
    Matched MeSH terms: Alzheimer Disease/genetics*
  2. Emerging Roles of Sirtuin 6 in Alzheimer's Disease
    Mohamad Nasir NF, Zainuddin A, Shamsuddin S
    J Mol Neurosci, 2018 Feb;64(2):157-161.
    PMID: 29260452 DOI: 10.1007/s12031-017-1005-y
    Alzheimer's disease (AD) is a neurodegenerative disease that is imposing an increasing burden on society. Currently, AD is the leading cause of senile dementia worldwide. Despite the long existence of AD, there is lack of therapies for AD, suggesting that new and effective treatment strategy must be explored. At present, sirtuin pathway has attracted attention from the researchers due to its promising results in laboratory models of aging. In addition, our understanding in the roles of sirtuin 6 in AD has expanded. It has been identified to be involved in telomere maintenance, DNA repair, genome integrity, energy metabolism, and inflammation, which ultimately regulate life span. Recent findings also demonstrate that sirtuin 6 is lacking in AD patients, proposing that it can be a new potential therapeutic target in AD. Therefore, exploring on how sirtuin 6 is related in AD manifestation may accelerate the research of AD further and benefits future AD patients. Keeping that in mind, this review aims to highlight the possible roles of sirtuin 6 in AD manifestation.
    Matched MeSH terms: Alzheimer Disease/genetics
  3. Apolipoprotein E (APOE) allele distribution in the world. Is APOE*4 a 'thrifty' allele?
    Corbo RM, Scacchi R
    Ann. Hum. Genet., 1999 Jul;63(Pt 4):301-10.
    PMID: 10738542
    Apolipoprotein E (APOE = gene, apoE = protein) plays a central role in plasma lipoprotein metabolism and in lipid transport within tissues. The APOE shows a genetic polymorphism determined by three common alleles, APOE*2, APOE*3, APOE*4 and the product of the three alleles differs in several functional properties. APOE is involved in the development of certain pathological conditions. In particular, the APOE*4 allele is a risk factor for susceptibility to coronary artery disease (CAD) and Alzheimer's Disease (AD). In the present study we analyzed the APOE allele distribution in the world. The APOE*3 is the most frequent in all the human groups, especially in populations with a long-established agricultural economy like those of the Mediterranean basin (0.849-0.898). The frequency of APOE*4, the ancestral allele, remains higher in populations like Pygmies (0.407) and Khoi San (0.370), aborigines of Malaysia (0.240) and Australia (0.260), Papuans (0.368), some Native Americans (0.280), and Lapps (0.310) where an economy of foraging still exists, or food supply is (or was until the recent past) scarce and sporadically available. The APOE*2 frequency fluctuates with no apparent trend (0.145-0.02) and is absent in Native Americans. We suggest that the APOE*4, based on some functional properties it has and on its distribution among human populations, could be identified as a 'thrifty' allele. The exposure of APOE*4 to the contemporary environmental conditions (Western diet, longer lifespans) could have rendered it a susceptibility allele for CAD and AD. The absence of the association of APOE*4 with CAD and AD in Sub-Saharan Africans, and its presence in African Americans, seems to confirm this hypothesis.
    Matched MeSH terms: Alzheimer Disease/genetics
  4. A review on advances of treatment modalities for Alzheimer's disease
    Se Thoe E, Fauzi A, Tang YQ, Chamyuang S, Chia AYY
    Life Sci, 2021 Jul 01;276:119129.
    PMID: 33515559 DOI: 10.1016/j.lfs.2021.119129
    Alzheimer's disease (AD) is a multifactorial neurodegenerative disease which is mainly characterized by progressive impairment in cognition, emotion, language and memory in older population. Considering the impact of AD, formulations of pharmaceutical drugs and cholinesterase inhibitors have been widely propagated, receiving endorsement by FDA as a form of AD treatment. However, these medications were gradually discovered to be ineffective in removing the root of AD pathogenesis but merely targeting the symptoms so as to improve a patient's cognitive outcome. Hence, a search for better disease-modifying alternatives is put into motion. Having a clear understanding of the neuroprotective mechanisms and diverse properties undertaken by specific genes, antibodies and nanoparticles is central towards designing novel therapeutic agents. In this review, we provide a brief introduction on the background of Alzheimer's disease, the biology of blood-brain barrier, along with the potentials and drawbacks associated with current therapeutic treatment avenues pertaining to gene therapy, immunotherapy and nanotherapy for better diagnosis and management of Alzheimer's disease.
    Matched MeSH terms: Alzheimer Disease/genetics
  5. Evaluation of the Expression of Amyloid Precursor Protein and the Ratio of Secreted Amyloid Beta 42 to Amyloid Beta 40 in SH-SY5Y Cells Stably Transfected with Wild-Type, Single-Mutant and Double-Mutant Forms of the APP Gene for the Study of Alzheimer's Disease Pathology
    Pahrudin Arrozi A, Shukri SNS, Wan Ngah WZ, Mohd Yusof YA, Ahmad Damanhuri MH, Makpol S
    Appl Biochem Biotechnol, 2017 Nov;183(3):853-866.
    PMID: 28417423 DOI: 10.1007/s12010-017-2468-6
    Neuroblastoma cell lines such as SH-SY5Y are the most frequently utilized models in neurodegenerative research, and their use has advanced the understanding of the pathology of neurodegeneration over the past few decades. In Alzheimer's disease (AD), several pathogenic mutations have been described, all of which cause elevated levels of pathological hallmarks such as amyloid-beta (Aβ). Although the genetics of Alzheimer's disease is well known, familial AD only accounts for a small number of cases in the population, with the rest being sporadic AD, which contains no known mutations. Currently, most of the in vitro models used to study AD pathogenesis only examine the level of Aβ42 as a confirmation of successful model generation and only perform comparisons between wild-type APP and single mutants of the APP gene. Recent findings have shown that the Aβ42/40 ratio in cerebrospinal fluid (CSF) is a better diagnostic indicator for AD patients than is Aβ42 alone and that more extensive Aβ formation, such as accumulation of intraneuronal Aβ, Aβ plaques, soluble oligomeric Aβ (oAβ), and insoluble fibrillar Aβ (fAβ) occurs in TgCRND8 mice expressing a double-mutant form (Swedish and Indiana) of APP, later leading to greater progressive impairment of the brain. In this study, we generated SH-SY5Y cells stably transfected separately with wild-type APP, the Swedish mutation of APP, and the Swedish and Indiana mutations of APP and evaluated the APP expression as well as the Aβ42/40 ratio in those cells. The double-mutant form of APP (Swedish/Indiana) expressed markedly high levels of APP protein and showed a high Aβ2/40 ratio compared to wild-type and single-mutant cells.
    Matched MeSH terms: Alzheimer Disease/genetics
  6. Fulltext APOE, TOMM40, and sex interactions on neural network connectivity
    Li T, Pappas C, Le ST, Wang Q, Klinedinst BS, Larsen BA, et al.
    Neurobiol Aging, 2022 Jan;109:158-165.
    PMID: 34740077 DOI: 10.1016/j.neurobiolaging.2021.09.020
    The Apolipoprotein E ε4 (APOE ε4) haplotype is the strongest genetic risk factor for late-onset Alzheimer's disease (AD). The Translocase of Outer Mitochondrial Membrane-40 (TOMM40) gene maintains cellular bioenergetics, which is disrupted in AD. TOMM40 rs2075650 ('650) G versus A carriage is consistently related to neural and cognitive outcomes, but it is unclear if and how it interacts with APOE. We examined 21 orthogonal neural networks among 8,222 middle-aged to aged participants in the UK Biobank cohort. ANOVA and multiple linear regression tested main effects and interactions with APOE and TOMM40 '650 genotypes, and if age and sex acted as moderators. APOE ε4 was associated with less strength in multiple networks, while '650 G versus A carriage was related to more language comprehension network strength. In APOE ε4 carriers, '650 G-carriage led to less network strength with increasing age, while in non-G-carriers this was only seen in women but not men. TOMM40 may shift what happens to network activity in aging APOE ε4 carriers depending on sex.
    Matched MeSH terms: Alzheimer Disease/genetics
  7. Fulltext Possible Epigenetic Role of Vitexin in Regulating Neuroinflammation in Alzheimer's Disease
    Yahaya MAF, Zolkiffly SZI, Moklas MAM, Hamid HA, Stanslas J, Zainol M, et al.
    J Immunol Res, 2020;2020:9469210.
    PMID: 32258178 DOI: 10.1155/2020/9469210
    Alzheimer's disease (AD) has been clinically characterized by a progressive degeneration of neurons which resulted in a gradual and irreversible cognitive impairment. The accumulation of Aβ and τ proteins in the brain contribute to the severity of the disease. Recently, vitexin compound has been the talk amongst researchers due to its pharmacological properties as anti-inflammation and anti-AD. However, the epigenetic mechanism of the compound in regulating the neuroinflammation activity is yet to be fully elucidated. Hence, this review discusses the potential of vitexin compound to have the pharmacoepigenetic property in regulating the neuroinflammation activity in relation to AD. It is with hope that the review would unveil the potential of vitexin as the candidate in treating AD.
    Matched MeSH terms: Alzheimer Disease/genetics
  8. Mutations, associated with early-onset Alzheimer's disease, discovered in Asian countries
    Bagyinszky E, Youn YC, An SS, Kim S
    Clin Interv Aging, 2016;11:1467-1488.
    PMID: 27799753
    Alzheimer's disease (AD), the most common form of senile dementia, is a genetically complex disorder. In most Asian countries, the population and the number of AD patients are growing rapidly, and the genetics of AD has been extensively studied, except in Japan. However, recent studies have been started to investigate the genes and mutations associated with AD in Korea, the People's Republic of China, and Malaysia. This review describes all of the known mutations in three early-onset AD (EOAD) causative genes (APP, PSEN1, and PSEN2) that were discovered in Asian countries. Most of the EOAD-associated mutations have been detected in PSEN1, and several novel PSEN1 mutations were recently identified in patients from various parts of the world, including Asia. Until 2014, no PSEN2 mutations were found in Asian patients; however, emerging studies from Korea and the People's Republic of China discovered probably pathogenic PSEN2 mutations. Since several novel mutations were discovered in these three genes, we also discuss the predictions on their pathogenic nature. This review briefly summarizes genome-wide association studies of late-onset AD and the genes that might be associated with AD in Asian countries. Standard sequencing is a widely used method, but it has limitations in terms of time, cost, and efficacy. Next-generation sequencing strategies could facilitate genetic analysis and association studies. Genetic testing is important for the accurate diagnosis and for understanding disease-associated pathways and might also improve disease therapy and prevention.
    Matched MeSH terms: Alzheimer Disease/genetics*
  9. Fulltext The Potential Benefits of Nanotechnology in Treating Alzheimer's Disease
    Ling TS, Chandrasegaran S, Xuan LZ, Suan TL, Elaine E, Nathan DV, et al.
    Biomed Res Int, 2021;2021:5550938.
    PMID: 34285915 DOI: 10.1155/2021/5550938
    Alzheimer's disease is a neurodegenerative disorder that is caused by the accumulation of beta-amyloid plaques in the brain. Currently, there is no definitive cure available to treat Alzheimer's disease. The available medication in the market has the ability to only slow down its progression. However, nanotechnology has shown its superiority that can be applied for medical usage and it has a great potential in the therapy of Alzheimer's disease, specifically in the disease diagnosis and providing an alternative approach to treat Alzheimer's disease. This is done by increasing the efficiency of drug delivery by penetrating and overcoming the blood-brain barrier. Having said that, there are limitations that need to be further investigated and researched in order to minimize the adverse effects and potential toxicity and to improve drug bioavailability. The recent advances in the treatment of Alzheimer's disease using nanotechnology include the regeneration of stem cells, nanomedicine, and neuroprotection. In this review, we will discuss the advancement of nanotechnology which helps in the diagnosis and treatment of neurodegenerative disorders such as Alzheimer's disease as well as its challenges.
    Matched MeSH terms: Alzheimer Disease/genetics
  10. A novel rat model of Alzheimer's disease based on lentiviral-mediated expression of mutant APP
    Parsi S, Pandamooz S, Heidari S, Naji M, Morfini G, Ahmadiani A, et al.
    Neuroscience, 2015 Jan 22;284:99-106.
    PMID: 25270904 DOI: 10.1016/j.neuroscience.2014.09.045
    Alzheimer's disease (AD) is characterized by progressive and irreversible cognitive and memory impairment. The discovery of familial forms of AD (fAD) in association with specific gene mutations facilitated the generation of numerous rodent models. These models in turn proved valuable for the study of molecular mechanisms underlying AD pathogenesis, and facilitated translational research and preclinical drug development. This study aimed to introduce a new rat model of AD simulating some aspects of the sporadic cases of disease.
    Matched MeSH terms: Alzheimer Disease/genetics*
  11. Mechanisms of action of amyloid-beta and its precursor protein in neuronal cell death
    Leong YQ, Ng KY, Chye SM, Ling APK, Koh RY
    Metab Brain Dis, 2020 01;35(1):11-30.
    PMID: 31811496 DOI: 10.1007/s11011-019-00516-y
    Extracellular senile plaques and intracellular neurofibrillary tangles are the neuropathological findings of the Alzheimer's disease (AD). Based on the amyloid cascade hypothesis, the main component of senile plaques, the amyloid-beta (Aβ) peptide, and its derivative called amyloid precursor protein (APP) both have been found to place their central roles in AD development for years. However, the recent therapeutics have yet to reverse or halt this disease. Previous evidence demonstrates that the accumulation of Aβ peptides and APP can exert neurotoxicity and ultimately neuronal cell death. Hence, we discuss the mechanisms of excessive production of Aβ peptides and APP serving as pathophysiologic stimuli for the initiation of various cell signalling pathways including apoptosis, necrosis, necroptosis and autophagy which lead to neuronal cell death. Conversely, the activation of such pathways could also result in the abnormal generation of APP and Aβ peptides. An elucidation of actions of APP and its metabolite, Aβ, could be vital in suggesting novel therapeutic opportunities.
    Matched MeSH terms: Alzheimer Disease/genetics
  12. Fulltext Current Concepts of Neurodegenerative Mechanisms in Alzheimer's Disease
    Magalingam KB, Radhakrishnan A, Ping NS, Haleagrahara N
    Biomed Res Int, 2018;2018:3740461.
    PMID: 29707568 DOI: 10.1155/2018/3740461
    Neurodegenerative diseases are hereditary or sporadic conditions that result in the progressive loss of the structure and function of neurons as well as neuronal death. Although a range of diseases lie under this umbrella term, Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases that affect a large population around the globe. Alzheimer's disease is characterized by the abnormal accumulation of extracellular amyloid-β plaques and intraneuronal neurofibrillary tangles in brain regions and manifests as a type of dementia in aged individuals that results in memory loss, multiple cognitive abnormalities, and intellectual disabilities that interfere with quality of life. Since the discovery of AD, a wealth of new information has emerged that delineates the causes, mechanisms of disease, and potential therapeutic agents, but an effective remedy to cure the diseases has not been identified yet. This could be because of the complexity of the disease process, as it involves various contributing factors that include environmental factors and genetic predispositions. This review summarizes the current understanding on neurodegenerative mechanisms that lead to the emergence of the pathology of AD.
    Matched MeSH terms: Alzheimer Disease/genetics
  13. Epigenomic approach in understanding Alzheimer's disease and type 2 diabetes mellitus
    Shaik MM, Gan SH, Kamal MA
    CNS Neurol Disord Drug Targets, 2014 Mar;13(2):283-9.
    PMID: 24074446 DOI: 10.2174/18715273113126660181
    Cognitive decline is a debilitating feature of Alzheimer's disease (AD). The causes leading to such impairment are still poorly understood and effective treatments for AD are still unavailable. Type 2 diabetes mellitus (T2DM) has been identified as a risk factor for AD due to desensitisation of insulin receptors in the brain. Recent studies have suggested that epigenetic mechanisms may also play a pivotal role in the pathogenesis of both AD and T2DM. This article describes the correlation between AD and T2DM and provides the insights to the epigenetics of AD. Currently, more research is needed to clarify the exact role of epigenetic regulation in the course and development of AD and also in relation to insulin. Research conducted especially in the earlier stages of the disease could provide more insight into its underlying pathophysiology to help in early diagnosis and the development of more effective treatment strategies.
    Matched MeSH terms: Alzheimer Disease/genetics*
  14. Fulltext Emerging pathways to neurodegeneration: Dissecting the critical molecular mechanisms in Alzheimer's disease, Parkinson's disease
    Tan SH, Karri V, Tay NWR, Chang KH, Ah HY, Ng PQ, et al.
    Biomed Pharmacother, 2019 Mar;111:765-777.
    PMID: 30612001 DOI: 10.1016/j.biopha.2018.12.101
    Neurodegenerative diseases are usually sporadic in nature and commonly influenced by a wide range of genetic, life style and environmental factors. A unifying feature of Alzheimer's disease (AD) and Parkinson's disease (PD) is the abnormal accumulation and processing of mutant or damaged intra and extracellular proteins; this leads to neuronal vulnerability and dysfunction in the brain. Through a detailed review of ubiquitin proteasome, mRNA splicing, mitochondrial dysfunction, and oxidative stress pathway interrelation on neurodegeneration can improve the understanding of the disease mechanism. The identified pathways common to AD and PD nominate promising new targets for further studies, and as well as biomarkers. These insights suggested would likely provide major stimuli for developing unified treatment approaches to combat neurodegeneration. More broadly, pathways can serve as vehicles for integrating findings from diverse studies of neurodegeneration. The evidence examined in this review provides a brief overview of the current literature on significant pathways in promoting in AD, PD. Additionally, these insights suggest that biomarkers and treatment strategies may require simultaneous targeting of multiple components.
    Matched MeSH terms: Alzheimer Disease/genetics
  15. Fulltext Endothelin type B receptor promotes cofilin rod formation and dendritic loss in neurons by inducing oxidative stress and cofilin activation
    Tam SW, Feng R, Lau WK, Law AC, Yeung PK, Chung SK
    J Biol Chem, 2019 08 16;294(33):12495-12506.
    PMID: 31248984 DOI: 10.1074/jbc.RA118.005155
    Endothelin-1 (ET-1) is a neuroactive peptide produced by neurons, reactive astrocytes, and endothelial cells in the brain. Elevated levels of ET-1 have been detected in the post-mortem brains of individuals with Alzheimer's disease (AD). We have previously demonstrated that overexpression of astrocytic ET-1 exacerbates memory deficits in aged mice or in APPK670/M671 mutant mice. However, the effects of ET-1 on neuronal dysfunction remain elusive. ET-1 has been reported to mediate superoxide formation in the vascular system via NADPH oxidase (NOX) and to regulate the actin cytoskeleton of cancer cell lines via the cofilin pathway. Interestingly, oxidative stress and cofilin activation were both reported to mediate one of the AD histopathologies, cofilin rod formation in neurons. This raises the possibility that ET-1 mediates neurodegeneration via oxidative stress- or cofilin activation-driven cofilin rod formation. Here, we demonstrate that exposure to 100 nm ET-1 or to a selective ET type B receptor (ETB) agonist (IRL1620) induces cofilin rod formation in dendrites of primary hippocampal neurons, accompanied by a loss of distal dendrites and a reduction in dendritic length. The 100 nm IRL1620 exposure induced superoxide formation and cofilin activation, which were abolished by pretreatment with a NOX inhibitor (5 μm VAS2870). Moreover, IRL1620-induced cofilin rod formation was partially abolished by pretreatment with a calcineurin inhibitor (100 nm FK506), which suppressed cofilin activation. In conclusion, our findings suggest a role for ETB in neurodegeneration by promoting cofilin rod formation and dendritic loss via NOX-driven superoxide formation and cofilin activation.
    Matched MeSH terms: Alzheimer Disease/genetics
  16. Fulltext Reconstructing directed gene regulatory network by only gene expression data
    Zhang L, Feng XK, Ng YK, Li SC
    BMC Genomics, 2016 Aug 18;17 Suppl 4:430.
    PMID: 27556418 DOI: 10.1186/s12864-016-2791-2
    BACKGROUND: Accurately identifying gene regulatory network is an important task in understanding in vivo biological activities. The inference of such networks is often accomplished through the use of gene expression data. Many methods have been developed to evaluate gene expression dependencies between transcription factor and its target genes, and some methods also eliminate transitive interactions. The regulatory (or edge) direction is undetermined if the target gene is also a transcription factor. Some methods predict the regulatory directions in the gene regulatory networks by locating the eQTL single nucleotide polymorphism, or by observing the gene expression changes when knocking out/down the candidate transcript factors; regrettably, these additional data are usually unavailable, especially for the samples deriving from human tissues.

    RESULTS: In this study, we propose the Context Based Dependency Network (CBDN), a method that is able to infer gene regulatory networks with the regulatory directions from gene expression data only. To determine the regulatory direction, CBDN computes the influence of source to target by evaluating the magnitude changes of expression dependencies between the target gene and the others with conditioning on the source gene. CBDN extends the data processing inequality by involving the dependency direction to distinguish between direct and transitive relationship between genes. We also define two types of important regulators which can influence a majority of the genes in the network directly or indirectly. CBDN can detect both of these two types of important regulators by averaging the influence functions of candidate regulator to the other genes. In our experiments with simulated and real data, even with the regulatory direction taken into account, CBDN outperforms the state-of-the-art approaches for inferring gene regulatory network. CBDN identifies the important regulators in the predicted network: 1. TYROBP influences a batch of genes that are related to Alzheimer's disease; 2. ZNF329 and RB1 significantly regulate those 'mesenchymal' gene expression signature genes for brain tumors.

    CONCLUSION: By merely leveraging gene expression data, CBDN can efficiently infer the existence of gene-gene interactions as well as their regulatory directions. The constructed networks are helpful in the identification of important regulators for complex diseases.

    Matched MeSH terms: Alzheimer Disease/genetics*
  17. Receptor-Interacting Protein Kinase 1 (RIPK1) as a Potential Therapeutic Target: An Overview of Its Possible Role in the Pathogenesis of Alzheimer's Disease
    Chan HH, Koh RY, Lim CL, Leong CO
    Curr Alzheimer Res, 2019;16(10):907-918.
    PMID: 31642777 DOI: 10.2174/1567205016666191023102422
    Alzheimer's Disease (AD) is an age-dependent neurodegenerative disorder, the most common type of dementia that is clinically characterized by the presence of beta-amyloid (Aβ) extracellularly and intraneuronal tau protein tangles that eventually leads to the onset of memory and cognition impairment, development of psychiatric symptoms and behavioral disorders that affect basic daily activities. Current treatment approved by the U.S Food and Drug Administration (FDA) for AD is mainly focused on the symptoms but not on the pathogenesis of the disease. Recently, receptor-interacting protein kinase 1 (RIPK1) has been identified as a key component in the pathogenesis of AD through necroptosis. Furthermore, genetic and pharmacological suppression of RIPK1 has been shown to revert the phenotype of AD and its mediating pathway is yet to be deciphered. This review is aimed to provide an overview of the pathogenesis and current treatment of AD with the involvement of autophagy as well as providing a novel insight into RIPK1 in reverting the progression of AD, probably through an autophagy machinery.
    Matched MeSH terms: Alzheimer Disease/genetics
  18. Fulltext REST and Neural Gene Network Dysregulation in iPSC Models of Alzheimer's Disease
    Meyer K, Feldman HM, Lu T, Drake D, Lim ET, Ling KH, et al.
    Cell Rep, 2019 01 29;26(5):1112-1127.e9.
    PMID: 30699343 DOI: 10.1016/j.celrep.2019.01.023
    The molecular basis of the earliest neuronal changes that lead to Alzheimer's disease (AD) is unclear. Here, we analyze neural cells derived from sporadic AD (SAD), APOE4 gene-edited and control induced pluripotent stem cells (iPSCs). We observe major differences in iPSC-derived neural progenitor (NP) cells and neurons in gene networks related to neuronal differentiation, neurogenesis, and synaptic transmission. The iPSC-derived neural cells from SAD patients exhibit accelerated neural differentiation and reduced progenitor cell renewal. Moreover, a similar phenotype appears in NP cells and cerebral organoids derived from APOE4 iPSCs. Impaired function of the transcriptional repressor REST is strongly implicated in the altered transcriptome and differentiation state. SAD and APOE4 expression result in reduced REST nuclear translocation and chromatin binding, and disruption of the nuclear lamina. Thus, dysregulation of neural gene networks may set in motion the pathologic cascade that leads to AD.
    Matched MeSH terms: Alzheimer Disease/genetics*
  19. Fulltext APP, PSEN1, and PSEN2 Mutations in Asian Patients with Early-Onset Alzheimer Disease
    Giau VV, Bagyinszky E, Youn YC, An SSA, Kim S
    Int J Mol Sci, 2019 Sep 25;20(19).
    PMID: 31557888 DOI: 10.3390/ijms20194757
    The number of patients with Alzheimer's disease (AD) is rapidly increasing in Asia. Mutations in the amyloid protein precursor (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) genes can cause autosomal dominant forms of early-onset AD (EOAD). Although these genes have been extensively studied, variant classification remains a challenge, highlighting the need to colligate mutations across populations. In this study, we performed a genetic screening for mutations in the APP, PSEN1, and PSEN2 genes in 200 clinically diagnosed EOAD patients across four Asian countries, including Thailand, Malaysia, the Philippines, and Korea, between 2009 and 2018. Thirty-two (16%) patients presented pathogenic APP, PSEN1, or PSEN2 variants; eight (25%), 19 (59%), and five (16%) of the 32 patients presented APP, PSEN1, and PSEN2 variants, respectively. Among the 21 novel and known non-synonymous variants, five APP variants were found in Korean patients and one APP variant was identified in a Thai patient with EOAD. Nine, two, and one PSEN1 mutation was found in a Korean patient, Malaysian siblings, and a Thai patient, respectively. Unlike PSEN1 mutations, PSEN2 mutations were rare in patients with EOAD; only three variants were found in Korean patients with EOAD. Comparison of AD-causative point mutations in Asian countries; our findings explained only a small fraction of patients, leaving approximately 84% (p = 0.01) of autosomal dominant pedigrees genetically unexplained. We suggest that the use of high-throughput sequencing technologies for EOAD patients can potentially improve our understanding of the molecular mechanisms of AD.
    Matched MeSH terms: Alzheimer Disease/genetics*
  20. Tocotrienol-Rich Fraction Modulates Amyloid Pathology and Improves Cognitive Function in AβPP/PS1 Mice
    Ibrahim NF, Yanagisawa D, Durani LW, Hamezah HS, Damanhuri HA, Wan Ngah WZ, et al.
    J Alzheimers Dis, 2017;55(2):597-612.
    PMID: 27716672
    Alzheimer's disease (AD) is the most common cause of dementia. The cardinal neuropathological characteristic of AD is the accumulation of amyloid-β (Aβ) into extracellular plaques that ultimately disrupt neuronal function and lead to neurodegeneration. One possible therapeutic strategy therefore is to prevent Aβ aggregation. Previous studies have suggested that vitamin E analogs slow AD progression in humans. In the present study, we investigated the effects of the tocotrienol-rich fraction (TRF), a mixture of vitamin E analogs from palm oil, on amyloid pathology in vitro and in vivo. TRF treatment dose-dependently inhibited the formation of Aβ fibrils and Aβ oligomers in vitro. Moreover, daily TRF supplementation to AβPPswe/PS1dE9 double transgenic mice for 10 months attenuated Aβ immunoreactive depositions and thioflavin-S-positive fibrillar type plaques in the brain, and eventually improved cognitive function in the novel object recognition test compared with control AβPPswe/PS1dE9 mice. The present result indicates that TRF reduced amyloid pathology and improved cognitive functions, and suggests that TRF is a potential therapeutic agent for AD.
    Matched MeSH terms: Alzheimer Disease/genetics
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