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Fransquet PD, Lacaze P, Saffery R, McNeil J, Woods R, Ryan J. Blood DNA methylation as a potential biomarker of dementia: A systematic review. Alzheimers Dement 2017; 14:81-103. [PMID: 29127806 DOI: 10.1016/j.jalz.2017.10.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/27/2017] [Accepted: 10/07/2017] [Indexed: 01/22/2023]
Abstract
Dementia is a major public health issue with rising prevalence rates, but many individuals remain undiagnosed. Accurate and timely diagnosis is key for the optimal targeting of interventions. A noninvasive, easily measurable peripheral biomarker would have greatest utility in population-wide diagnostic screening. Epigenetics, including DNA methylation, is implicated in dementia; however, it is unclear whether epigenetic changes can be detected in peripheral tissue. This study aimed to systematically review the evidence for an association between dementia and peripheral DNA methylation. Forty-eight studies that measured DNA methylation in peripheral blood were identified, and 67% reported significant associations with dementia. However, most studies were underpowered and limited by their case-control design. We emphasize the need for future longitudinal studies on large well-characterized populations, measuring epigenetic patterns in asymptomatic individuals. A biomarker detectable in the preclinical stages of the disease would have the greatest utility in future intervention and treatment trials.
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Affiliation(s)
- Peter D Fransquet
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; Disease Epigenetics, Murdoch Children's Research Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Paul Lacaze
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Richard Saffery
- Disease Epigenetics, Murdoch Children's Research Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - John McNeil
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Robyn Woods
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Joanne Ryan
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; Disease Epigenetics, Murdoch Children's Research Institute, The University of Melbourne, Parkville, Victoria, Australia; INSERM, Neuropsychiatry: Epidemiological and Clinical Research, University of Montpellier, Montpellier, France.
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Lu H, Liu X, Deng Y, Qing H. DNA methylation, a hand behind neurodegenerative diseases. Front Aging Neurosci 2013; 5:85. [PMID: 24367332 PMCID: PMC3851782 DOI: 10.3389/fnagi.2013.00085] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 11/17/2013] [Indexed: 12/13/2022] Open
Abstract
Epigenetic alterations represent a sort of functional modifications related to the genome that are not responsible for changes in the nucleotide sequence. DNA methylation is one of such epigenetic modifications that have been studied intensively for the past several decades. The transfer of a methyl group to the 5 position of a cytosine is the key feature of DNA methylation. A simple change as such can be caused by a variety of factors, which can be the cause of many serious diseases including several neurodegenerative diseases. In this review, we have reviewed and summarized recent progress regarding DNA methylation in four major neurodegenerative diseases: Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). The studies of these four major neurodegenerative diseases conclude the strong suggestion of the important role DNA methylation plays in these diseases. However, each of these diseases has not yet been understood completely as details in some areas remain unclear, and will be investigated in future studies. We hope this review can provide new insights into the understanding of neurodegenerative diseases from the epigenetic perspective.
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Affiliation(s)
| | | | | | - Hong Qing
- School of Life Science, Beijing Institute of TechnologyBeijing, China
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Hou Y, Chen H, He Q, Jiang W, Luo T, Duan J, Mu N, He Y, Wang H. Changes in methylation patterns of multiple genes from peripheral blood leucocytes of Alzheimer's disease patients. Acta Neuropsychiatr 2013; 25:66-76. [PMID: 25287307 DOI: 10.1111/j.1601-5215.2012.00662.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Efforts aiming at identifying biomarkers and corresponding methods for early diagnosis of Alzheimer's disease (AD) might be the most appropriate strategy to initiate promising new treatments and/or prevention of AD OBJECTIVE: The aim of our study is to assess the association of DNA methylation pattern of various leucocyte genes with AD pathogenesis in order to find potential biomarkers and corresponding methods for molecular diagnosis of AD. METHODS DNA methylation level of various genes in AD patients and normal population were compared by bisulphite sequencing PCR and methylation-specific PCR (MSP). Furthermore, real-time PCR was used to explore the effects of DNA methylation on the expression of target genes. RESULTS Results showed significant hypermethylation of mammalian orthologue of Sir2 (SIRT1) gene in AD patients compared with normal population. Meanwhile, changes in methylation level of SIRT1 gene between different severities of AD were also found. Specific primers were designed from the SIRT1 CpG islands to differentiate AD and control group by MSP method. Besides, significant demethylation of β-amyloid precursor protein (APP) gene was observed in AD patients, whereas no difference was observed in other AD-related genes. Moreover, significant decrease in expression of SIRT1 gene and increase in expression of APP gene were also found in AD patients. In addition, the expression level of SIRT1/APP genes was associated with the severity, but not with the age or gender, of AD patients. CONCLUSION SIRT1 and APP might be the interesting candidate biomarkers and valuable for clinical diagnosis or treatment of AD.
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Affiliation(s)
- Yaping Hou
- 1 Department of Anatomy & Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, PR China
| | - Huayun Chen
- 2 Daan Gene Diagnostic Center, Sun Yat-sen University, Guangzhou, PR China
| | - Qiong He
- 1 Department of Anatomy & Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, PR China
| | - Wei Jiang
- 1 Department of Anatomy & Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, PR China
| | - Tao Luo
- 1 Department of Anatomy & Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, PR China
| | - Jinhai Duan
- 3 East Department of Neurology, Guangdong General Hospital, Guangzhou, PR China
| | - Nan Mu
- 6 Guangzhou Brain Hospital, Guangzhou, PR China
| | - Yunshao He
- 2 Daan Gene Diagnostic Center, Sun Yat-sen University, Guangzhou, PR China
| | - Huaqiao Wang
- 1 Department of Anatomy & Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, PR China
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Pietrzak M, Rempala G, Nelson PT, Zheng JJ, Hetman M. Epigenetic silencing of nucleolar rRNA genes in Alzheimer's disease. PLoS One 2011; 6:e22585. [PMID: 21799908 PMCID: PMC3142181 DOI: 10.1371/journal.pone.0022585] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 06/30/2011] [Indexed: 11/25/2022] Open
Abstract
Background Ribosomal deficits are documented in mild cognitive impairment (MCI), which often represents an early stage Alzheimer's disease (AD), as well as in advanced AD. The nucleolar rRNA genes (rDNA), transcription of which is critical for ribosomal biogenesis, are regulated by epigenetic silencing including promoter CpG methylation. Methodology/Principal Findings To assess whether CpG methylation of the rDNA promoter was dysregulated across the AD spectrum, we analyzed brain samples from 10 MCI-, 23 AD-, and, 24 age-matched control individuals using bisulfite mapping. The rDNA promoter became hypermethylated in cerebro-cortical samples from MCI and AD groups. In parietal cortex, the rDNA promoter was hypermethylated more in MCI than in advanced AD. The cytosine methylation of total genomic DNA was similar in AD, MCI, and control samples. Consistent with a notion that hypermethylation-mediated silencing of the nucleolar chromatin stabilizes rDNA loci, preventing their senescence-associated loss, genomic rDNA content was elevated in cerebrocortical samples from MCI and AD groups. Conclusions/Significance In conclusion, rDNA hypermethylation could be a new epigenetic marker of AD. Moreover, silencing of nucleolar chromatin may occur during early stages of AD pathology and play a role in AD-related ribosomal deficits and, ultimately, dementia.
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Affiliation(s)
- Maciej Pietrzak
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky United States of America
| | - Grzegorz Rempala
- Department of Biostatistics, Medical College of Georgia, Augusta, Georgia, United States of America
| | - Peter T. Nelson
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States of America
| | - Jing-Juan Zheng
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky United States of America
| | - Michal Hetman
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky United States of America
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky United States of America
- * E-mail:
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Liu D, Zhou P, Zhang L, Wu G, Zheng Y, He F. Differential expression of Oct4 in HPV-positive and HPV-negative cervical cancer cells is not regulated by DNA methyltransferase 3A. Tumour Biol 2011; 32:941-50. [PMID: 21674242 DOI: 10.1007/s13277-011-0196-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 05/24/2011] [Indexed: 11/28/2022] Open
Abstract
The colony-forming ability of cervical cancer is affected by many factors. Oct4, an important transcription factor, is highly expressed in several tumors and promotes the colony-forming ability of cancer cells. Thus, it is considered a potential target for the treatment of cancer. However, we know little about the expression level of Oct4 and its epigenetic regulatory mechanism in cervical cancer cells. In this study, we are the first to observe that human papillomavirus (HPV)-positive cervical cancer cell lines (HeLa, Caski) have a stronger colony-forming ability than HPV-negative cervical cancer cell lines (C-33A). Moreover, the expression level of Oct4 in both HeLa and Caski cells was also higher than that in C-33A cells. We then confirmed that there was a negative correlation between the expression of Oct4 and DNMT3A in these three types of cervical cancer cells, whereas DNA methyltransferase 1 and 3B had no differences among the cell lines. However, after DNA methylation in both key regulatory regions of the Oct4 gene and the genomic levels were analyzed, we found that DNA methyltransferase 3A could neither regulate the expression of Oct4 nor affect the whole level of genomic DNA methylation. These results suggest three points: (1) Oct4 might be treated as a new target for the treatment of cervical cancer, (2) we could not inhibit the expression of Oct4 by DNA demethylation, and (3) HPV virus might initiate cervical carcinogenesis by upregulation of Oct4 expression.
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Affiliation(s)
- Dongbo Liu
- Department of Biochemistry and Molecular Biology, Third Military Medical University, 30 Gaotanyan, Shapingba, Chongqing, 400038, China
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Chouliaras L, Rutten BPF, Kenis G, Peerbooms O, Visser PJ, Verhey F, van Os J, Steinbusch HWM, van den Hove DLA. Epigenetic regulation in the pathophysiology of Alzheimer's disease. Prog Neurobiol 2010; 90:498-510. [PMID: 20097254 DOI: 10.1016/j.pneurobio.2010.01.002] [Citation(s) in RCA: 177] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Revised: 12/18/2009] [Accepted: 01/14/2010] [Indexed: 11/19/2022]
Abstract
With the aging of the population, the growing incidence and prevalence of Alzheimer's disease (AD) increases the burden on individuals and society as a whole. To date, the pathophysiology of AD is not yet fully understood. Recent studies have suggested that epigenetic mechanisms may play a pivotal role in its course and development. The most frequently studied epigenetic mechanisms are DNA methylation and histone modifications, and investigations relevant to aging and AD are presented in this review. Various studies on human postmortem brain samples and peripheral leukocytes, as well as transgenic animal models and cell culture studies relevant to AD will be discussed. From those, it is clear that aging and AD are associated with epigenetic dysregulation at various levels. Moreover, data on e.g. twin studies in AD support the notion that epigenetic mechanisms mediate the risk for AD. Conversely, it is still not fully clear whether the observed epigenetic changes actually represent a cause or a consequence of the disease. This is mainly due to the fact that most clinical investigations on epigenetics in AD are conducted in samples of patients already in an advanced stage of the disease. Evidently, more research is needed in order to clarify the exact role of epigenetic regulation in the course and development of AD. Research on earlier stages of the disease could provide more insight into its underlying pathophysiology, possibly contributing to the establishment of early diagnosis and the development of more effective treatment strategies.
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Affiliation(s)
- Leonidas Chouliaras
- School for Mental Health and Neuroscience (MHeNS), Faculty of Health, Medicine and Life Sciences, European Graduate School of Neuroscience (EURON), Maastricht University Medical Centre, PO Box 616, 6200 MD Maastricht, The Netherlands
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