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Aging-associated DNA methylation changes in middle-aged individuals: the Young Finns study.

ABSTRACT: Chronological aging-associated changes in the human DNA methylome have been studied by multiple epigenome-wide association studies (EWASs). Certain CpG sites have been identified as aging-associated in multiple studies, and the majority of the sites identified in various studies show common features regarding location and direction of the methylation change. However, as a whole, the sets of aging-associated CpGs identified in different studies, even with similar tissues and age ranges, show only limited overlap. In this study, we further explore and characterize CpG sites that show close relationship between their DNA methylation level and chronological age during adulthood and which bear the relationship regardless of blood cell type heterogeneity.In this study, with a multivariable regression model adjusted for cell type heterogeneity, we identified 1202 aging-associated CpG sites (a-CpGs, FDR < 5%), in whole blood in a population with an especially narrow age range (40 - 49 years). Repeatedly reported a-CpGs located in genes ELOVL2, FHL2, PENK and KLF14 were also identified. Regions with aging-associated hypermethylation were enriched regarding several gene ontology (GO) terms (especially in the cluster of developmental processes), whereas hypomethylated sites showed no enrichment. The genes with higher numbers of a-CpG hits were more often hypermethylated with advancing age. The comparison analysis revealed that of the 1202 a-CpGs identified in the present study, 987 were identified as differentially methylated also between nonagenarians and young adults in a previous study (The Vitality 90+ study), and importantly, the directions of changes were identical in the previous and in the present study.Here we report that aging-associated DNA methylation features can be identified in a middle-aged population with an age range of only 9 years. A great majority of these sites have been previously reported as aging-associated in a population aged 19 to 90 years. Aging is associated with different types of changes in DNA methylation, clock-like as well as random. We speculate that the a-CpGs identified here in a population with a narrow age-range represent clock-like changes, as they showed concordant methylation behavior in population spanning whole adulthood as well.

SUBMITTER: Kananen L

PROVIDER: S-EPMC4746895 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

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Aging-associated DNA methylation changes in middle-aged individuals: the Young Finns study.

Kananen L L Marttila S S Nevalainen T T Jylhävä J J Mononen N N Kähönen M M Raitakari O T OT Lehtimäki T T Hurme M M

BMC genomics 20160209

<h4>Background</h4>Chronological aging-associated changes in the human DNA methylome have been studied by multiple epigenome-wide association studies (EWASs). Certain CpG sites have been identified as aging-associated in multiple studies, and the majority of the sites identified in various studies show common features regarding location and direction of the methylation change. However, as a whole, the sets of aging-associated CpGs identified in different studies, even with similar tissues and ag ...[more]

PMID: 26861258

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Project description:Background Chronological aging-associated changes in the human DNA methylome are studied by multiple epigenome-wide association studies (EWAS); however, the aging-associated DNAmet changes identified among different age groups and tissues vary and especially the rates of aging-associated alterations in the epigenome during adulthood remain unclear. Here, we further explore and characterize CpG-sites where DNA methylation levels alter at a constant rate during adulthood and are also independent of blood cell type heterogeneity. Results In the study, we observed 1,202 aging-associated CpG-sites (a-CpGs), of which 48% were hypermethylated with advancing age in whole blood with an especially narrow age range (40 - 49 years). Repeatedly reported a-CpGs in ELOVL2, FHL2, PENK and KLF14 were also identified. Regions with aging-associated hypermethylation were enriched to several gene ontology terms (especially on the cluster of developmental processes), while hypomethylated sites showed no enrichment. The genes with a higher number of a-CpG hits were more often hypermethylated. Of the 1,202 aging-associated CpG-sites in the present study, 987 were identified in previous study (Vitality 90+) as differentially methylated also between nonagenarians and young adults in a previous study, and importantly, the directions of changes were identical in the previous and in the present study. Conclusions The set of 987 replicated a-CpGs presented here are altered in strong association with chronological aging in the whole range of adulthood. Consequently, future studies should note the variability of the types of a-CpGs, and the a-CpGs presented here should be dissociated from the environmental-sensitive CpG-sites or from regions that are associated with aging in a non-linear manner due to the accumulation of senescence-related features. This report offers detailed and verified pool of a-CpGs in which DNAmet levels associate linearly with chronological age and of which are different from the non-linearly changing ones.

Project description:BACKGROUND: Age-related physiological, biochemical and functional changes in mammalian skeletal muscle have been shown to begin at the mid-point of the lifespan. However, the underlying changes in DNA methylation that occur during this turning point of the muscle aging process have not been clarified. To explore age-related genomic methylation changes in skeletal muscle, we employed young (0.5 years old) and middle-aged (7 years old) pigs as models to survey genome-wide DNA methylation in the longissimus dorsi muscle using a methylated DNA immunoprecipitation sequencing approach. RESULTS: We observed a tendency toward a global loss of DNA methylation in the gene-body region of the skeletal muscle of the middle-aged pigs compared with the young group. We determined the genome-wide gene expression pattern in the longissimus dorsi muscle using microarray analysis and performed a correlation analysis using DMR (differentially methylated region)-mRNA pairs, and we found a significant negative correlation between the changes in methylation levels within gene bodies and gene expression. Furthermore, we identified numerous genes that show age-related methylation changes that are potentially involved in the aging process. The methylation status of these genes was confirmed using bisulfite sequencing PCR. The genes that exhibited a hypomethylated gene body in middle-aged pigs were over-represented in various proteolysis and protein catabolic processes, suggesting an important role for these genes in age-related muscle atrophy. In addition, genes associated with tumorigenesis exhibited aged-related differences in methylation and expression levels, suggesting an increased risk of disease associated with increased age. CONCLUSIONS: This study provides a comprehensive analysis of genome-wide DNA methylation patterns in aging pig skeletal muscle. Our findings will serve as a valuable resource in aging studies, promoting the pig as a model organism for human aging research and accelerating the development of comparative animal models in aging research.

Project description:Background: Age-related physiological, biochemical and functional changes in mammalian skeletal muscle have been shown to begin at the mid-point of the lifespan. However, the underlying changes in DNA methylation that occur during this turning point of the muscle aging process have not been clarified. To explore age-related genomic methylation changes in skeletal muscle, we employed young (0.5 years old) and middle-aged (7 years old) pigs as models to survey genome-wide DNA methylation in the longissimus dorsi muscle using a methylated DNA immunoprecipitation sequencing approach. Results: We observed a tendency toward a global loss of DNA methylation in the gene-body region of the skeletal muscle of the middle-aged pigs compared with the young group. We determined the genome-wide gene expression pattern in the longissimus dorsi muscle using microarray analysis and performed a correlation analysis using DMR (differentially methylated region)-mRNA pairs, and we found a significant negative correlation between the changes in methylation levels within gene bodies and gene expression. Furthermore, we identified numerous genes that show age-related methylation changes that are potentially involved in the aging process. The methylation status of these genes was confirmed using bisulfite sequencing PCR. The genes that exhibited a hypomethylated gene body in middle-aged pigs were over-represented in various proteolysis and protein catabolic processes, suggesting an important role for these genes in age-related muscle atrophy. In addition, genes associated with tumorigenesis exhibited aged-related differences in methylation and expression levels, suggesting an increased risk of disease associated with increased age. Conclusions: This study provides a comprehensive analysis of genome-wide DNA methylation patterns in aging pig skeletal muscle. Our findings will serve as a valuable resource in aging studies, promoting the pig as a model organism for human aging research and accelerating the development of comparative animal models in aging research. We collected the longissimus dorsi muscles tissue from Jinhua pigs which aged 0.5 year and seven years and study the genome-wide DNA methylation difference between the two age periods.

Project description:Age-related methylation changes have been identified in various tissues and organisms, yet the underlying DNA methylation alterations in muscle aging process have not been clearly clarified. Whilst, many studies revealed that the structural and functional changes in skeletal muscle during aging process started from the mid-point of lifespan. In this study, we used pigs aged 0.5 year and 7 years, representing young and middle-aged periods. Using methylated DNA immunoprecipitation sequencing, we performed comprehensive genome-wide DNA methylation profiling for longissimus dorsi muscle in young and middle-aged pigs. We found more genes showed differently methylated in genebody. In details, 185 human ortholog genes contained DMRs that located in the promoter region, while 657 genes and 1063 genes with DMRs in gene body showed hypermethylation and hypomethylation in MA pigs, respectively. From the gene enrichment analysis, genebody hypermethylated genes showed significant enrichment for several molecular functions such as M-bM-^@M-^XGTPase regulator activityM-bM-^@M-^Y, M-bM-^@M-^XATP bindingM-bM-^@M-^Y and M-bM-^@M-^Xprotein kinase activityM-bM-^@M-^Y. Notably, genebody hypomethylated genes showed significant enrichment for various proteolysis and protein catabolic process. However, genes with DMR in their promoter region were not significantly enriched in any biology process. Proteolysis-associated genes, such as FOXO3 and FGFR1, showed different genebody methylation and mRNA expression level in two age groups, which may contribute to muscle atrophy during aging. Especially, other tumorigenesis-associated genes including GPI and GRB2, exhibited increasing mRNA level in middle-aged pigs, suggesting the possible higher risk of having cancer in human middle-aged period. Our results will serve as a valuable resource in aging studies, promote pig as a model organism for human aging research and accelerate the considerable development of comparative animal models in aging research. We collected the longissimus dorsi muscles tissue from Jinhua pigs which aged 0.5 year and seven years and study the genome-wide DNA methylation difference and the genome-wide gene expression profile between the two age periods. This submission represents transcriptome component of study.

Project description:Background Age-related physiological, biochemical and functional changes in mammalian skeletal muscle have been shown to begin at the mid-point of the lifespan. However, the underlying changes in DNA methylation that occur during this turning point of the muscle aging process have not been clarified. To explore age-related genomic methylation changes in skeletal muscle, we employed young (0.5 years old) and middle-aged (7 years old) pigs as models to survey genome-wide DNA methylation in the longissimus dorsi muscle using a methylated DNA immunoprecipitation sequencing approach. Results We observed a tendency toward a global loss of DNA methylation in the gene-body region of the skeletal muscle of the middle-aged pigs compared with the young group. We determined the genome-wide gene expression pattern in the longissimus dorsi muscle using microarray analysis and performed a correlation analysis using DMR (differentially methylated region)-mRNA pairs, and we found a significant negative correlation between the changes in methylation levels within gene bodies and gene expression. Furthermore, we identified numerous genes that show age-related methylation changes that are potentially involved in the aging process. The methylation status of these genes was confirmed using bisulfite sequencing PCR. The genes that exhibited a hypomethylated gene body in middle-aged pigs were over-represented in various proteolysis and protein catabolic processes, suggesting an important role for these genes in age-related muscle atrophy. In addition, genes associated with tumorigenesis exhibited aged-related differences in methylation and expression levels, suggesting an increased risk of disease associated with increased age. Conclusions This study provides a comprehensive analysis of genome-wide DNA methylation patterns in aging pig skeletal muscle. Our findings will serve as a valuable resource in aging studies, promoting the pig as a model organism for human aging research and accelerating the development of comparative animal models in aging research.

Project description:Nonalcoholic fatty liver is associated with obesity-related metabolic disturbances, but little is known about the metabolic perturbations preceding fatty liver disease. We performed comprehensive metabolic profiling to assess how circulating metabolites, such as lipoprotein lipids, fatty acids, amino acids, and glycolysis-related metabolites, reflect the presence of and future risk for fatty liver in young adults. Sixty-eight lipids and metabolites were quantified by nuclear magnetic resonance metabolomics in the population-based Young Finns Study from serum collected in 2001 (n = 1,575), 2007 (n = 1,509), and 2011 (n = 2,002). Fatty liver was diagnosed by ultrasound in 2011 when participants were aged 34-49 years (19% prevalence). Cross-sectional associations as well as 4-year and 10-year risks for fatty liver were assessed by logistic regression. Metabolites across multiple pathways were strongly associated with the presence of fatty liver (P < 0.0007 for 60 measures in age-adjusted and sex-adjusted cross-sectional analyses). The strongest direct associations were observed for extremely large very-low-density lipoprotein triglycerides (odds ratio [OR] = 4.86 per 1 standard deviation, 95% confidence interval 3.48-6.78), other very-low-density lipoprotein measures, and branched-chain amino acids (e.g., leucine OR = 2.94, 2.51-3.44). Strong inverse associations were observed for high-density lipoprotein measures, e.g., high-density lipoprotein size (OR = 0.36, 0.30-0.42) and several fatty acids including omega-6 (OR = 0.37, 0.32-0.42). The metabolic associations were attenuated but remained significant after adjusting for waist, physical activity, alcohol consumption, and smoking (P < 0.0007). Similar aberrations in the metabolic profile were observed already 10 years before fatty liver diagnosis.ConclusionCirculating lipids, fatty acids, and amino acids reflect fatty liver independently of routine metabolic risk factors; these metabolic aberrations appear to precede the development of fatty liver in young adults. (Hepatology 2017;65:491-500).

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Aging-associated DNA methylation changes in middle-aged individuals: the Young Finns study.

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Aging-associated DNA methylation changes in middle-aged individuals: the Young Finns study.

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