Aging-associated distinctive DNA methylation changes of LINE-1 retrotransposons in pure cell-free DNA from human blood
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ABSTRACT:
SUBMITTER: Mahmood W
PROVIDER: S-EPMC7746734 | biostudies-literature | 2020 Jan
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND: Human aging is associated with DNA methylation changes at specific sites in the genome. These epigenetic modifications may be used to track donor age for forensic analysis or to estimate biological age. RESULTS: We perform a comprehensive analysis of methylation profiles to narrow down 102 age-related CpG sites in blood. We demonstrate that most of these age-associated methylation changes are reversed in induced pluripotent stem cells (iPSCs). Methylation levels at three age-related CpGs--located in the genes ITGA2B, ASPA and PDE4C--were subsequently analyzed by bisulfite pyrosequencing of 151 blood samples. This epigenetic aging signature facilitates age predictions with a mean absolute deviation from chronological age of less than 5 years. This precision is higher than age predictions based on telomere length. Variation of age predictions correlates moderately with clinical and lifestyle parameters supporting the notion that age-associated methylation changes are associated more with biological age than with chronological age. Furthermore, patients with acquired aplastic anemia or dyskeratosis congenita--two diseases associated with progressive bone marrow failure and severe telomere attrition--are predicted to be prematurely aged. CONCLUSIONS: Our epigenetic aging signature provides a simple biomarker to estimate the state of aging in blood. Age-associated DNA methylation changes are counteracted in iPSCs. On the other hand, over-estimation of chronological age in bone marrow failure syndromes is indicative for exhaustion of the hematopoietic cell pool. Thus, epigenetic changes upon aging seem to reflect biological aging of blood.
| S-EPMC4053864 | biostudies-other
Project description:BackgroundMethylation of deoxyribonucleic acid (DNA) is an epigenetic regulator of gene expression that changes with age, but its contribution to aging-related disorders, including high blood pressure (BP), is still largely unknown. We examined the relation of BP to the methylation of retrotransposon sequences of DNA and of selected candidate genes.MethodsThis investigation included 789 elderly participants in the Normative Aging Study, ranging in age from 55 to 100 years, who had longitudinal measurements of DNA methylation. In these subjects' DNA we measured the proportion of methylated sites in retrotransposable sequences and in pro-inflammatory genes, expressed as the percent of 5-methylated cytosines (%5mC) among all cytosines. From one to four methylation measurements were made for each subject between 1999 and 2009. We fit mixed-effects models, using repeated measures of BP as the outcome and DNA methylation as the explanatory variable, adjusting for confounding variables. We also fit a Bayesian mixed-effects structural equation model to account for heterogeneity in the effects of methylation sites within each gene.ResultsAn increase in inter-quartile range (IQR) in the methylation of Alu elements was associated with an increase of 0.97 mm Hg in diastolic blood pressure (DBP) (95% CI 0.32-1.57), but no such association was observed for long interspersed nuclear element-1 (LINE-1). We also found positive associations between DBP and methylation of the genes for toll-like receptor 2 (TLR2) and inducible nitric oxide synthase (iNOS), and a negative association between DBP and methylation of the gene for interferon-? (IFN-?). Associations between methylation and systolic blood pressure (SBP) were weaker than those between methylation and DBP. Bayesian mixed-effects structural equation model results were similar for both DBP and SBP models.ConclusionsThe results of our study suggest that changes in DNA methylation of some pro-inflammatory genes and retrotransposable elements are related to small changes in BP.
| S-EPMC3600626 | biostudies-literature
Project description:Background Individuals of the same chronological age may exhibit diverse susceptibilities to death. However, few studies have investigated the associations between blood pressure and the accelerated aging. Methods and Results A cross-sectional study was conducted in 288 adults aged ≥50 years. We assessed the DNA methylation-based measures of biological age using CpG sites on the Illumina HumanMethylationEPIC BeadChip. Epigenetic age acceleration metrics were derived by regressing residuals (ΔAge) and ratios (aging rate) of DNA methylation age on chronological age. Dose-response relationships between blood pressure and epigenetic age acceleration were quantified using multiple linear regression and restricted cubic regression models. We found that each 10-mm Hg increase in systolic blood pressure was associated with 0.608 (95% CI, 0.231-0.984) years increase in ΔAge and 0.007 (95% CI, 0.002-0.012) increase in aging rate; meanwhile, for pulse pressure, the increase was 1.12 (95% CI, 0.625-1.61) years for ΔAge and 0.013 (95% CI, 0.007-0.020) for aging rate. Subgroup analysis showed that the significant associations of systolic blood pressure and pulse pressure with epigenetic age acceleration appeared to be limited to women, although interactions between blood pressure and sex were not significant (P values for interaction >0.05). The combination of women and hypertension was associated with a much higher increase in ΔAge (β [95% CI], 4.05 [1.07-7.02]) and aging rate (β [95% CI], 0.047 [0.008-0.087]), compared with male participants without hypertension. Conclusions Our findings suggested that high systolic blood pressure and pulse pressure were associated with the epigenetic age acceleration, providing important clues for relationships between blood pressure and epigenetic aging.
| S-EPMC9238504 | biostudies-literature
Project description:De novo DNA methylation (DNAme) during mouse oogenesis occurs within transcribed regions enriched for H3K36me3. As many oocyte transcripts originate in long terminal repeats (LTRs), which are heterogeneous even between closely related mammals, we examined whether species-specific LTR-initiated transcription units (LITs) shape the oocyte methylome. Here we identify thousands of syntenic regions in mouse, rat, and human that show divergent DNAme associated with private LITs, many of which initiate in lineage-specific LTR retrotransposons. Furthermore, CpG island (CGI) promoters methylated in mouse and/or rat, but not human oocytes, are embedded within rodent-specific LITs and vice versa. Notably, at a subset of such CGI promoters, DNAme persists on the maternal genome in fertilized and parthenogenetic mouse blastocysts or in human placenta, indicative of species-specific epigenetic inheritance. Polymorphic LITs are also responsible for disparate DNAme at promoter CGIs in distantly related mouse strains, revealing that LITs also promote intra-species divergence in CGI DNAme.
| S-EPMC6102241 | biostudies-literature
Project description:Parkinson disease (PD) is a multifactorial neurodegenerative disorder with high incidence in the elderly, where environmental and genetic factors are involved in etiology. In addition, epigenetic mechanisms, including deregulation of DNA methylation have been recently associated to PD. As accurate diagnosis cannot be achieved pre-mortem, identification of early pathological changes is crucial to enable therapeutic interventions before major neuropathological damage occurs. Here we investigated genome-wide DNA methylation in brain and blood samples from PD patients and observed a distinctive pattern of methylation involving many genes previously associated to PD, therefore supporting the role of epigenetic alterations as a molecular mechanism in neurodegeneration. Importantly, we identified concordant methylation alterations in brain and blood, suggesting that blood might hold promise as a surrogate for brain tissue to detect DNA methylation in PD and as a source for biomarker discovery.
| S-EPMC3891683 | biostudies-literature
Project description:DNA methylation has been associated with age-related disease. Intra-individual changes in gene-specific DNA methylation over time in a community-based cohort has not been well described. We estimated the change in DNA methylation due to aging for nine genes in an elderly, community-dwelling cohort of men. Seven hundred and eighty four men from the Veterans Administration Normative Aging Study who were living in metropolitan Boston from 1999-2009 donated a blood sample for DNA methylation analysis at clinical examinations repeated at approximately 3-5 year intervals. We used mixed effects regression models. Aging was significantly associated with decreased methylation of GCR, iNOS and TLR2 and with increased methylation of IFN?, F3, CRAT and OGG. Obstructive pulmonary disease at baseline modified the effect of aging on methylation of IFN? (interaction p = 0.04). For participants who had obstructive pulmonary disease at their baseline visit, the rate of change of methylation of IFN? was -0.05% 5-methyl-cytosine (5-mC) per year (95% CI: -0.22, 0.13), but was 0.14% 5-mC per year (95% CI: 0.05, 0.24) for those without this condition. Models with random slopes indicated significant heterogeneity in the effect of aging on methylation of GCR, iNOS and OGG. These findings suggest that DNA methylation may reflect differential biological aging.
| S-EPMC3329504 | biostudies-literature
Project description:BackgroundThe long terminal repeat (LTR) retrotransposons and the non-LTR retrotransposons (LINE-1 or L1) make up more than one-third of the mouse genome. Because of their abundance, the retrotransposons are the major players in genomic structure and function. While much attention has been focused on the biology of retrotransposons, little is known about the chromatin structure of these elements or the potential role of epigenetic marks on the regulation of retrotransposon expression.FindingsUsing sequential chromatin immunoprecipitation analysis, we analyzed the cohabitation of several post-translational histone modifications in the promoter regions of mouse L1 and LTR retrotransposons. We show here that the variant histone H2A.Z selectively present in L1 promoters. Notably, H2A.Z and trimethylated histone H3 (H3K9me3) co-localize in the same genomic location of the L1 promoter along with heterochromatin-binding protein HP1α. In contrast, MmERV and intracisternal A-particle (IAP) classes of LTR promoters are enriched with core histone H2A and heterochromatic trimethylated histone H4 (H4K20me3). These distinctive patterns of chromatin modifications are relatively consistent irrespective of cell type.ConclusionsChromatin structure regulates the expression of retrotransposons. LINE-1 elements are associated with H2A.Z and HP1α-containing constitutive heterochromatin, while the LTR elements are enriched with H2A and the H4K20me3-type of facultative heterochromatin. Our findings demonstrate that different epigenetic mechanisms operate in the mouse genome to silence different classes of retrotransposons.
| S-EPMC4177394 | biostudies-literature
Project description:Several recent studies reported aging effects on DNA methylation levels of individual CpG dinucleotides. But it is not yet known whether aging-related consensus modules, in the form of clusters of correlated CpG markers, can be found that are present in multiple human tissues. Such a module could facilitate the understanding of aging effects on multiple tissues.We therefore employed weighted correlation network analysis of 2,442 Illumina DNA methylation arrays from brain and blood tissues, which enabled the identification of an age-related co-methylation module. Module preservation analysis confirmed that this module can also be found in diverse independent data sets. Biological evaluation showed that module membership is associated with Polycomb group target occupancy counts, CpG island status and autosomal chromosome location. Functional enrichment analysis revealed that the aging-related consensus module comprises genes that are involved in nervous system development, neuron differentiation and neurogenesis, and that it contains promoter CpGs of genes known to be down-regulated in early Alzheimer's disease. A comparison with a standard, non-module based meta-analysis revealed that selecting CpGs based on module membership leads to significantly increased gene ontology enrichment, thus demonstrating that studying aging effects via consensus network analysis enhances the biological insights gained.Overall, our analysis revealed a robustly defined age-related co-methylation module that is present in multiple human tissues, including blood and brain. We conclude that blood is a promising surrogate for brain tissue when studying the effects of age on DNA methylation profiles.
| S-EPMC4053733 | biostudies-literature
Project description:Cardiomyopathy (CM) is an intrinsic weakening of myocardium with contractile dysfunction and congestive heart failure (CHF). CHF has been postulated to result from decreased mitochondrial energy production and oxidative stress. Effects of decreased mitochondrial oxygen consumption also can accelerate with aging. We previously showed DNA methylation changes in human hearts with CM. This was associated with mitochondrial DNA depletion, being another molecular marker of CM. We examined the relationship between mitochondrial dysfunction and cardiac epigenetic DNA methylation changes in both young and old mice. We used genetically engineered C57Bl/6 mice transgenic for a cardiac-specific mutant of the mitochondrial polymerase-γ (termed Y955C). Y955C mice undergo left ventricular hypertrophy (LVH) at a young age (∼ 94 days old), and LVH decompensated to CHF at old age (∼ 255 days old). Results found 95 genes differentially expressed as a result of Y955C expression, while 4,452 genes were differentially expressed as a result of aging hearts. Moreover, cardiac DNA methylation patterns differed between Y955C (4,506 peaks with 68.5% hypomethylation) and aged hearts (73,286 peaks with 80.2% hypomethylated). Correlatively, of the 95 Y955C-dependent differentially expressed genes, 30 genes (31.6%) also displayed differential DNA methylation; in the 4,452 age-dependent differentially expressed genes, 342 genes (7.7%) displayed associated DNA methylation changes. Both Y955C and aging demonstrated significant enrichment of CACGTG-associated E-box motifs in differentially methylated regions. Cardiac mitochondrial polymerase dysfunction alters nuclear DNA methylation. Furthermore, aging causes a robust change in cardiac DNA methylation that is partially associated with mitochondrial polymerase dysfunction.
| S-EPMC4824151 | biostudies-literature
Project description:Despite evidence linking obesity to impaired immune function, little is known about the specific mechanisms. Because of emerging evidence that immune responses are epigenetically regulated, we hypothesized that DNA methylation changes are involved in obesity induced immune dysfunction and aimed to identify these changes.We conducted a genome wide methylation analysis on seven obese cases and seven lean controls aged 14 to 18 years from extreme ends of the obesity distribution and performed further validation of six CpG sites from six genes in 46 obese cases and 46 lean controls aged 14 to 30 years.In comparison with the lean controls, we observed one CpG site in the UBASH3A gene showing higher methylation levels and one CpG site in the TRIM3 gene showing lower methylation levels in the obese cases in both the genome wide step (P = 5 × 10(-6) and P = 2 × 10(-5) for the UBASH3A and the TRIM3 gene respectively) and the validation step (P = 0.008 and P = 0.001 for the UBASH3A and the TRIM3 gene respectively).Our results provide evidence that obesity is associated with methylation changes in blood leukocyte DNA. Further studies are warranted to determine the causal direction of this relationship as well as whether such methylation changes can lead to immune dysfunction.
| S-EPMC3016263 | biostudies-literature