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Coppedè F, Tannorella P, Stoccoro A, Chico L, Siciliano G, Bonuccelli U, Migliore L. Methylation analysis of DNA repair genes in Alzheimer's disease. Mech Ageing Dev 2016; 161:105-111. [PMID: 27080585 DOI: 10.1016/j.mad.2016.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/30/2016] [Accepted: 04/07/2016] [Indexed: 10/22/2022]
Abstract
There is substantial evidence of impaired DNA repair activities in Alzheimer's disease (AD) neurons and peripheral tissues, inducing some investigators to speculate that this could partially result from promoter hypermethylation of DNA repair genes, resulting in gene silencing in those tissues. In the present study a screening cohort composed by late-onset AD (LOAD) patients and healthy matched controls was evaluated with a commercially available DNA methylation array for the assessment of the methylation levels of a panel of 22 genes involved in major DNA repair pathways in blood DNA. We then applied a cost-effective PCR based methylation-sensitive high-resolution melting (MS-HRM) technique, in order to evaluate the promoter methylation levels of the following DNA repair genes: OGG1, PARP1, MRE11A, BRCA1, MLH1, and MGMT. The analysis was performed in blood DNA from 56 LOAD patients and 55 matched controls, including the samples previously assessed with the DNA methylation array as validating samples. Both approaches revealed that all the investigated genes were largely hypomethylated in LOAD and control blood DNA, and no difference between groups was observed. Collectively, present data do not support an increased promoter methylation of some of the major DNA repair genes in blood DNA of AD patients.
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Affiliation(s)
- Fabio Coppedè
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Via Roma 55, 56126 Pisa, Italy.
| | - Pierpaola Tannorella
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Via Roma 55, 56126 Pisa, Italy
| | - Andrea Stoccoro
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Via Roma 55, 56126 Pisa, Italy; Doctoral School in Genetics Oncology and Clinical Medicine, University of Siena, Siena, Italy
| | - Lucia Chico
- Unit of Neurology, Department of Neuroscience, Pisa University Hospital, Via Roma 67, 56126 Pisa, Italy
| | - Gabriele Siciliano
- Unit of Neurology, Department of Neuroscience, Pisa University Hospital, Via Roma 67, 56126 Pisa, Italy; Department of Clinical and Experimental Medicine, University of Pisa, Neurological Clinic, Via Roma 67, 56126 Pisa, Italy
| | - Ubaldo Bonuccelli
- Unit of Neurology, Department of Neuroscience, Pisa University Hospital, Via Roma 67, 56126 Pisa, Italy; Department of Clinical and Experimental Medicine, University of Pisa, Neurological Clinic, Via Roma 67, 56126 Pisa, Italy
| | - Lucia Migliore
- Department of Translational Research and New Technologies in Medicine and Surgery, Section of Medical Genetics, University of Pisa, Via Roma 55, 56126 Pisa, Italy.
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Yu L, Chibnik LB, Yang J, McCabe C, Xu J, Schneider JA, De Jager PL, Bennett DA. Methylation profiles in peripheral blood CD4+ lymphocytes versus brain: The relation to Alzheimer's disease pathology. Alzheimers Dement 2016; 12:942-951. [PMID: 27016692 DOI: 10.1016/j.jalz.2016.02.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 01/12/2016] [Accepted: 02/16/2016] [Indexed: 12/13/2022]
Abstract
INTRODUCTION We investigated the change in DNA methylation in peripheral blood CD4+ lymphocytes over time, examined the relation between CD4+ lymphocytes and brain methylation, and compared their associations with AD pathology. METHODS Genome-wide methylation was measured three times in 41 older persons using Illumina Infinium HumanMethylation450 array. The two CD4+ lymphocytes measures were at study baseline and proximate to death. Brain tissue came from frozen dorsolateral prefrontal cortex. RESULTS Global methylation features were conserved across tissue. At individual CpG sites, methylation level was concordant between the two CD4+ lymphocytes but more diffuse between CD4+ lymphocytes and brain. Previous associations of brain methylation with neuritic plaques at target methylation sites were not replicated in CD4+ lymphocytes. DISCUSSION There is no strong evidence of change in CD4+ lymphocytes methylation among older persons over an average of 7.5 years. Methylation associations with AD pathology found in neocortex are not directly reflected in CD4+ lymphocytes.
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Affiliation(s)
- Lei Yu
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.
| | - Lori B Chibnik
- Program in Translational NeuroPsychiatric Genomics, Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Jingyun Yang
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Cristin McCabe
- Program in Translational NeuroPsychiatric Genomics, Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Jishu Xu
- Program in Translational NeuroPsychiatric Genomics, Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Julie A Schneider
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA; Department of Pathology, Rush University Medical Center, Chicago, IL, USA
| | - Philip L De Jager
- Program in Translational NeuroPsychiatric Genomics, Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
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Increased MTHFR promoter methylation in mothers of Down syndrome individuals. Mutat Res 2016; 787:1-6. [PMID: 26926955 DOI: 10.1016/j.mrfmmm.2016.02.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/29/2016] [Accepted: 02/18/2016] [Indexed: 02/06/2023]
Abstract
Despite that advanced maternal age at conception represents the major risk factor for the birth of a child with Down syndrome (DS), most of DS babies are born from women aging less than 35 years. Studies performed in peripheral lymphocytes of those women revealed several markers of global genome instability, including an increased frequency of micronuclei, shorter telomeres and impaired global DNA methylation. Furthermore, young mothers of DS individuals (MDS) are at increased risk to develop dementia later in life, suggesting that they might be "biologically older" than mothers of euploid babies of similar age. Mutations in folate pathway genes, and particularly in the methylenetetrahydrofolate reductase (MTHFR) one, have been often associated with maternal risk for a DS birth as well as with risk of dementia in the elderly. Recent studies pointed out that also changes in MTHFR methylation levels can contribute to human disease, but nothing is known about MTHFR methylation in MDS tissues. We investigated MTHFR promoter methylation in DNA extracted from perypheral lymphocytes of 40 MDS and 44 matched control women that coinceived their children before 35 years of age, observing a significantly increased MTHFR promoter methylation in the first group (33.3 ± 8.1% vs. 28.3 ± 5.8%; p=0.001). In addition, the frequency of micronucleated lymphocytes was available from the women included in the study, was higher in MDS than control mothers (16.1 ± 8.6‰ vs. 10.5 ± 4.3‰; p=0.0004), and correlated with MTHFR promoter methylation levels (r=0.33; p=0.006). Present data suggest that MTHFR epimutations are likely to contribute to the increased genomic instability observed in cells from MDS, and could play a role in the risk of birth of a child with DS as well as in the onset of age related diseases in those women.
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