scholarly journals Ethnicity-specific and overlapping alterations of brain hydroxymethylome in Alzheimer’s disease

2019 ◽  
Vol 29 (1) ◽  
pp. 149-158
Author(s):  
Lixia Qin ◽  
Qian Xu ◽  
Ziyi Li ◽  
Li Chen ◽  
Yujing Li ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Frontal Cortex ◽  
Cytosine Methylation ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Hypoxia Inducible Factor ◽  
Specific Gene ◽  
Dna Hydroxymethylation ◽  
Genome Wide

Abstract 5-Methylcytosine (5mC), generated through the covalent addition of a methyl group to the fifth carbon of cytosine, is the most prevalent DNA modification in humans and functions as a critical player in the regulation of tissue and cell-specific gene expression. 5mC can be oxidized to 5-hydroxymethylcytosine (5hmC) by ten–eleven translocation (TET) enzymes, which is enriched in brain. Alzheimer’s disease (AD) is the most common neurodegenerative disorder, and several studies using the samples collected from Caucasian cohorts have found that epigenetics, particularly cytosine methylation, could play a role in the etiological process of AD. However, little research has been conducted using the samples of other ethnic groups. Here we generated genome-wide profiles of both 5mC and 5hmC in human frontal cortex tissues from late-onset Chinese AD patients and cognitively normal controls. We identified both Chinese-specific and overlapping differentially hydroxymethylated regions (DhMRs) with Caucasian cohorts. Pathway analyses revealed specific pathways enriched among Chinese-specific DhMRs, as well as the shared DhMRs with Caucasian cohorts. Furthermore, two important transcription factor-binding motifs, hypoxia-inducible factor 2α (HIF2α) and hypoxia-inducible factor 1α (HIF1α), were enriched in the DhMRs. Our analyses provide the first genome-wide profiling of DNA hydroxymethylation of the frontal cortex of AD patients from China, emphasizing an important role of 5hmC in AD pathogenesis and highlighting both ethnicity-specific and overlapping changes of brain hydroxymethylome in AD.

scholarly journals Genome-Wide DNA Methylation Differences Between Late-Onset Alzheimer's Disease and Cognitively Normal Controls in Human Frontal Cortex

2012 ◽  
Vol 29 (3) ◽  
pp. 571-588 ◽  
Author(s):  
Kelly M. Bakulski ◽  
Dana C. Dolinoy ◽  
Maureen A. Sartor ◽  
Henry L. Paulson ◽  
John R. Konen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Dna Methylation ◽  
Frontal Cortex ◽  
Late Onset ◽  
Cognitively Normal ◽  
Genome Wide ◽  
Human Frontal Cortex ◽  
Normal Controls

scholarly journals A histone acetylome-wide association study of Alzheimer’s disease: neuropathology-associated regulatory variation in the human entorhinal cortex

2017 ◽  
Author(s):  
Sarah J. Marzi ◽  
Teodora Ribarska ◽  
Adam R. Smith ◽  
Eilis Hannon ◽  
Jeremie Poschmann ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Entorhinal Cortex ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Association Studies ◽  
Amyloid Β ◽  
Genomic Variation ◽  
Genome Wide Association Studies ◽  
Genome Wide

AbstractAlzheimer’s disease (AD) is a chronic neurodegenerative disorder characterized by the progressive accumulation of amyloid-β (Aβ) plaques and neurofibrillary tangles in the neocortex. Recent studies have implicated a role for regulatory genomic variation in AD progression, finding widespread evidence for altered DNA methylation associated with neuropathology. To date, however, no study has systematically examined other types of regulatory genomic modifications in AD. In this study, we quantified genome-wide patterns of lysine H3K27 acetylation (H3K27ac) - a robust mark of active enhancers and promoters that is strongly correlated with gene expression and transcription factor binding - in entorhinal cortex samples from AD cases and matched controls (n = 47) using chromatin immunoprecipitation followed by highly parallel sequencing (ChIP-seq). Across ~182,000 robustly detected H3K27ac peak regions, we found widespread acetylomic variation associated with AD neuropathology, identifying 4,162 differential peaks (FDR < 0.05) between AD cases and controls. These differentially acetylated peaks are enriched in disease-specific biological pathways and include regions annotated to multiple genes directly involved in the progression of Aβ and tau pathology (e.g. APP, PSEN1, PSEN2, MAPT), as well as genomic regions containing variants associated with sporadic late-onset AD. This is the first study of variable H3K27ac yet undertaken in AD and the largest study investigating this modification in the entorhinal cortex. In addition to identifying molecular pathways associated with AD neuropathology, we present a framework for genome-wide studies of histone modifications in complex disease, integrating our data with results obtained from genome-wide association studies as well as other epigenetic marks profiled on the same samples.

scholarly journals Association and Gene–-Gene Interactions Study of Late-Onset Alzheimer’s Disease in the Russian Population

Genes ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1647
Author(s):  
Anna Bocharova ◽  
Kseniya Vagaitseva ◽  
Andrey Marusin ◽  
Natalia Zhukova ◽  
Irina Zhukova ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Factor Model ◽  
Late Onset ◽  
Interaction Network ◽  
Russian Population ◽  
Protein Protein Interaction ◽  
Protective Haplotype ◽  
Single Snps

Alzheimer’s disease (AD) is a neurodegenerative disorder, and represents the most common cause of dementia. In this study, we performed several different analyses to detect loci involved in development of the late onset AD in the Russian population. DNA samples from 472 unrelated subjects were genotyped for 63 SNPs using iPLEX Assay and real-time PCR. We identified five genetic loci that were significantly associated with LOAD risk for the Russian population (TOMM40 rs2075650, APOE rs429358 and rs769449, NECTIN rs6857, APOE ε4). The results of the analysis based on comparison of the haplotype frequencies showed two risk haplotypes and one protective haplotype. The GMDR analysis demonstrated three significant models as a result: a one-factor, a two-factor and a three-factor model. A protein–protein interaction network with three subnetworks was formed for the 24 proteins. Eight proteins with a large number of interactions are identified: APOE, SORL1, APOC1, CD33, CLU, TOMM40, CNTNAP2 and CACNA1C. The present study confirms the importance of the APOE-TOMM40 locus as the main risk locus of development and progress of LOAD in the Russian population. Association analysis and bioinformatics approaches detected interactions both at the association level of single SNPs and at the level of genes and proteins.

scholarly journals Summary-Based Methylome-Wide Association Analyses Suggest Potential Genetically Driven Epigenetic Heterogeneity of Alzheimer’s Disease

2020 ◽  
Vol 9 (5) ◽  
pp. 1489
Author(s):  
Alireza Nazarian ◽  
Anatoliy I. Yashin ◽  
Alexander M. Kulminski
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Tissue Samples ◽  
Significance Level ◽  
Association Analyses ◽  
Functional Studies ◽  
Genome Wide ◽  
Summary Data

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with no curative treatment available. Exploring the genetic and non-genetic contributors to AD pathogenesis is essential to better understand its underlying biological mechanisms, and to develop novel preventive and therapeutic strategies. We investigated potential genetically driven epigenetic heterogeneity of AD through summary data-based Mendelian randomization (SMR), which combined results from our previous genome-wide association analyses with those from two publicly available methylation quantitative trait loci studies of blood and brain tissue samples. We found that 152 probes corresponding to 113 genes were epigenetically associated with AD at a Bonferroni-adjusted significance level of 5.49E-07. Of these, 10 genes had significant probes in both brain-specific and blood-based analyses. Comparing males vs. females and hypertensive vs. non-hypertensive subjects, we found that 22 and 79 probes had group-specific associations with AD, respectively, suggesting a potential role for such epigenetic modifications in the heterogeneous nature of AD. Our analyses provided stronger evidence for possible roles of four genes (i.e., AIM2, C16orf80, DGUOK, and ST14) in AD pathogenesis as they were also transcriptionally associated with AD. The identified associations suggest a list of prioritized genes for follow-up functional studies and advance our understanding of AD pathogenesis.

scholarly journals Genes, pathways and risk prediction in Alzheimer’s disease

2019 ◽  
Author(s):  
John Hardy ◽  
Valentina Escott-Price
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Membrane Damage ◽  
Disease Process ◽  
Complete Understanding ◽  
Induced Membrane ◽  
Genome Wide ◽  
Key Factor ◽  
Risk Of Disease

Abstract The failure of recent clinical trials in Alzheimer's disease has highlighted the need for the development of a more complete understanding of the pathogenesis of the disorder and also a belief that therapies may only work if given very early in the disease process before overt symptoms occur. The rare, early onset forms of the disease are all caused by mutations which make amyloid deposition a more likely event. Here we discuss the recent data showing that, in contrast, much of the risk of late onset disease is encoded by loci involved in lipid metabolism and/or encoded by microglia. We discuss these finding and suggest that amyloid induced membrane damage may be a key factor in disease and also review the evidence that genome wide genetic analysis can substantially help in the prediction of those individuals at high risk of disease in the general population.

scholarly journals Association Study of Genetic Variants inCDKN2A/CDKN2BGenes/Loci with Late-Onset Alzheimer's Disease

2011 ◽  
Vol 2011 ◽  
pp. 1-4
Author(s):  
Andrea Tedde ◽  
Irene Piaceri ◽  
Silvia Bagnoli ◽  
Ersilia Lucenteforte ◽  
Uwe Ueberham ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Genetic Variants ◽  
Genetic Variant ◽  
Case Control Study ◽  
Late Onset ◽  
Common Genetic Variant ◽  
Genome Wide ◽  
Control Study

Alzheimer's disease (AD) is the most common form of dementia clinically characterized by progressive impairment of memory and other cognitive functions. Many genetic researches in AD identified one common genetic variant (ε4) in Apolipoprotein E (APOE) gene as a risk factor for the disease. Two independent genome-wide studies demonstrated a new locus on chromosome 9p21.3 implicated in Late-Onset Alzheimer's Disease (LOAD) susceptibility in Caucasians. In the present study, we investigated the role of three SNP's in theCDKN2Agene (rs15515, rs3731246, and rs3731211) and one in theCDKN2Bgene (rs598664) located in 9p21.3 using an association case-control study carried out in a group of Caucasian subjects including 238 LOAD cases and 250 controls. The role ofCDKN2AandCDKN2Bgenetic variants in AD is not confirmed in our LOAD patients, and further studies are needed to elucidate the role of these genes in the susceptibility of AD.

scholarly journals Genetic underpinnings in Alzheimer’s disease – a review

2017 ◽  
Vol 29 (1) ◽  
pp. 21-38 ◽  
Author(s):  
Ahmed A. Moustafa ◽  
Mubashir Hassan ◽  
Doaa H. Hewedi ◽  
Iman Hewedi ◽  
Julia K. Garami ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Late Onset ◽  
Genetic Research ◽  
Twin Studies ◽  
Pedigree Analysis ◽  
Protein Signaling ◽  
Genetic Components ◽  
Genome Wide ◽  
Pharmacological Targets

AbstractIn this review, we discuss the genetic etiologies of Alzheimer’s disease (AD). Furthermore, we review genetic links to protein signaling pathways as novel pharmacological targets to treat AD. Moreover, we also discuss the clumps of AD-m ediated genes according to their single nucleotide polymorphism mutations. Rigorous data mining approaches justified the significant role of genes in AD prevalence. Pedigree analysis and twin studies suggest that genetic components are part of the etiology, rather than only being risk factors for AD. The first autosomal dominant mutation in the amyloid precursor protein (APP) gene was described in 1991. Later, AD was also associated with mutated early-onset (presenilin 1/2,PSEN1/2andAPP) and late-onset (apolipoprotein E,ApoE) genes. Genome-wide association and linkage analysis studies with identified multiple genomic areas have implications for the treatment of AD. We conclude this review with future directions and clinical implications of genetic research in AD.

scholarly journals The Triggering Receptor Expressed on Myeloid Cells 2: “TREM-ming” the Inflammatory Component Associated with Alzheimer's Disease

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Troy T. Rohn
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurofibrillary Tangles ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Senile Plaques ◽  
Myeloid Cells ◽  
Disease Process ◽  
Age Related

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by a progressive loss of memory and cognitive skills. Although much attention has been devoted concerning the contribution of the microscopic lesions, senile plaques, and neurofibrillary tangles to the disease process, inflammation has long been suspected to play a major role in the etiology of AD. Recently, a novel variant in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) has been identified that has refocused the spotlight back onto inflammation as a major contributing factor in AD. Variants in TREM2 triple one's risk of developing late-onset AD. TREM2 is expressed on microglial cells, the resident macrophages in the CNS, and functions to stimulate phagocytosis on one hand and to suppress cytokine production and inflammation on the other hand. The purpose of this paper is to discuss these recent developments including the potential role that TREM2 normally plays and how loss of function may contribute to AD pathogenesis by enhancing oxidative stress and inflammation within the CNS. In this context, an overview of the pathways linking beta-amyloid, neurofibrillary tangles (NFTs), oxidative stress, and inflammation will be discussed.

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