DNA methylation patterns in human adipose tissue in relation to diet and type 2 diabetes

Type 2 diabetes (T2D) is a common metabolic disease and its prevalence is increasing worldwide. Adipose tissue plays an important role in metabolic processes. Environmental factors may affect metabolic phenotypes and epigenetics may mediate this influence. We used Illumina 450k microarrays to study correlations between epigenetic patterns in human adipose tissue and environmental factors such as high-fat diets, impaired intrauterine environment and low birth weight as well as with type 2 diabetes.In study 1 we investigated whether the DNA methylation pattern in human adipose tissue is affected differently by a 7-week exposure to a diet high in either polyunsaturated fatty acids or saturated fatty acids. We found differences in methylation related to general fat overfeeding as well as between the two dietary groups.In study 2 we studied the effect of 5 days of overfeeding with a high fat diet on DNA methylation in adipose tissue compared to a control diet. The participants were either born with a normal or low birth weight and it allowed also to compare the effects of the diets on these two groups separately. There were differences in methylation between subjects born with a low compared with normal birth weight.In study 3 we used adipose tissue of a cohort of 14 monozygotic twin pairs discordant for type 2 diabetes in order to eliminate most of known confounding factors in comparing DNA methylation patterns as well as a case- control cohort for T2D. We found numerous differences in methylation in adipose tissue from subjects with T2D compared with controls, while less differences were found in the discordant twins.In study 4 we compared DNA methylation in adipose-derived stem and differentiated cells in subjects born with a low or normal birth weight. We found differences in gene expression in adipose-derived stem cells between low birth weight and normal birth weight groups but did not identify differences in methylation patterns possibly due to lack of statistical power.Overall, these studies contribute to a better understanding of the influence of environmental factors and type 2 diabetes on DNA methylation in human adipose tissue

DNA methylation partially mediates antidiabetic effects of metformin on HbA1c levels in individuals with type 2 diabetes

Aims: Despite metformin being used as first-line pharmacological therapy for type 2 diabetes, its underlying mechanisms remain unclear. We aimed to determine whether metformin altered DNA methylation in newlydiagnosed individuals with type 2 diabetes. Methods and Results: We found that metformin therapy is associated with altered methylation of 26 sites in blood from Scandinavian discovery and replication cohorts (FDR < 0.05), using MethylationEPIC arrays. The majority (88%) of these 26 sites were hypermethylated in patients taking metformin for ~ 3 months compared to controls, who had diabetes but had not taken any diabetes medication. Two of these blood-based methylation markers mirrored the epigenetic pattern in muscle and adipose tissue (FDR < 0.05). Four type 2 diabetes-associated SNPs were annotated to genes with differential methylation between metformin cases and controls, e.g., GRB10, RPTOR, SLC22A18AS and TH2LCRR. Methylation correlated with expression in human islets for two of these genes. Three metformin-associated methylation sites (PKNOX2, WDTC1 and MICB) partially mediate effects of metformin on follow-up HbA1c levels. When combining methylation of these three sites into a score, which was used in a causal mediation analysis, methylation was suggested to mediate up to 32% of metformin’s effects on HbA1c. Conclusion: Metformin-associated alterations in DNA methylation partially mediates metformin’s antidiabetic effects on HbA1c in newly-diagnosed individuals with type 2 diabetes

Abnormal epigenetic changes during differentiation of human skeletal muscle stem cells from obese subjects

Contains fulltext : 169731.pdf (publisher's version ) (Open Access)BACKGROUND: Human skeletal muscle stem cells are important for muscle regeneration. However, the combined genome-wide DNA methylation and expression changes taking place during adult myogenesis have not been described in detail and novel myogenic factors may be discovered. Additionally, obesity is associated with low relative muscle mass and diminished metabolism. Epigenetic alterations taking place during myogenesis might contribute to these defects. METHODS: We used Infinium HumanMethylation450 BeadChip Kit (Illumina) and HumanHT-12 Expression BeadChip (Illumina) to analyze genome-wide DNA methylation and transcription before versus after differentiation of primary human myoblasts from 14 non-obese and 14 obese individuals. Functional follow-up experiments were performed using siRNA mediated gene silencing in primary human myoblasts and a transgenic mouse model. RESULTS: We observed genome-wide changes in DNA methylation and expression patterns during differentiation of primary human muscle stem cells (myoblasts). We identified epigenetic and transcriptional changes of myogenic transcription factors (MYOD1, MYOG, MYF5, MYF6, PAX7, MEF2A, MEF2C, and MEF2D), cell cycle regulators, metabolic enzymes and genes previously not linked to myogenesis, including IL32, metallothioneins, and pregnancy-specific beta-1-glycoproteins. Functional studies demonstrated IL-32 as a novel target that regulates human myogenesis, insulin sensitivity and ATP levels in muscle cells. Furthermore, IL32 transgenic mice had reduced insulin response and muscle weight. Remarkably, approximately 3.7 times more methylation changes (147,161 versus 39,572) were observed during differentiation of myoblasts from obese versus non-obese subjects. In accordance, DNMT1 expression increased during myogenesis only in obese subjects. Interestingly, numerous genes implicated in metabolic diseases and epigenetic regulation showed differential methylation and expression during differentiation only in obese subjects. CONCLUSIONS: Our study identifies IL-32 as a novel myogenic regulator, provides a comprehensive map of the dynamic epigenome during differentiation of human muscle stem cells and reveals abnormal epigenetic changes in obesity

DNA methylation of loci within ABCG1 and PHOSPHO1 in blood DNA is associated with future type 2 diabetes risk

Identification of subjects with a high risk of developing type 2 diabetes (T2D) is fundamental for prevention of the disease. Consequently, it is essential to search for new biomarkers that can improve the prediction of T2D. The aim of this study was to examine whether 5 DNA methylation loci in blood DNA (ABCG1, PHOSPHO1, SOCS3, SREBF1, and TXNIP), recently reported to be associated with T2D, might predict future T2D in subjects from the Botnia prospective study. We also tested if these CpG sites exhibit altered DNA methylation in human pancreatic islets, liver, adipose tissue, and skeletal muscle from diabetic vs. non-diabetic subjects. DNA methylation at the ABCG1 locus cg06500161 in blood DNA was associated with an increased risk for future T2D (OR = 1.09, 95% CI = 1.02-1.16, P-value = 0.007, Q-value = 0.018), while DNA methylation at the PHOSPHO1 locus cg02650017 in blood DNA was associated with a decreased risk for future T2D (OR = 0.85, 95% CI = 0.75-0.95, P-value = 0.006, Q-value = 0.018) after adjustment for age, gender, fasting glucose, and family relation. Furthermore, the level of DNA methylation at the ABCG1 locus cg06500161 in blood DNA correlated positively with BMI, HbA1c, fasting insulin, and triglyceride levels, and was increased in adipose tissue and blood from the diabetic twin among monozygotic twin pairs discordant for T2D. DNA methylation at the PHOSPHO1 locus cg02650017 in blood correlated positively with HDL levels, and was decreased in skeletal muscle from diabetic vs. non-diabetic monozygotic twins. DNA methylation of cg18181703 (SOCS3), cg11024682 (SREBF1), and cg19693031 (TXNIP) was not associated with future T2D risk in subjects from the Botnia prospective study.Peer reviewe

Epigenome-Wide Association Study of Incident Type 2 Diabetes in a British Population: EPIC-Norfolk Study.

Epigenetic changes may contribute substantially to risks of diseases of aging. Previous studies reported seven methylation variable positions (MVPs) robustly associated with incident type 2 diabetes mellitus (T2DM). However, their causal roles in T2DM are unclear. In an incident T2DM case-cohort study nested within the population-based European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk cohort, we used whole blood DNA collected at baseline, up to 11 years before T2DM onset, to investigate the role of methylation in the etiology of T2DM. We identified 15 novel MVPs with robust associations with incident T2DM and robustly confirmed three MVPs identified previously (near to TXNIP, ABCG1, and SREBF1). All 18 MVPs showed directionally consistent associations with incident and prevalent T2DM in independent studies. Further conditional analyses suggested that the identified epigenetic signals appear related to T2DM via glucose and obesity-related pathways acting before the collection of baseline samples. We integrated genome-wide genetic data to identify methylation-associated quantitative trait loci robustly associated with 16 of the 18 MVPs and found one MVP, cg00574958 at CPT1A, with a possible direct causal role in T2DM. None of the implicated genes were previously highlighted by genetic association studies, suggesting that DNA methylation studies may reveal novel biological mechanisms involved in tissue responses to glycemia

Interactive systems of multipurpose direction in control of plant

The paper is concerned with plants of different branchs. The aim is to develop the methodical and applied aspects for creating interactive systems of multipurpose intention and their application in control. The development of interactive systems in direction of creating interactive systems of multipurpose intention which can be used simultaneously for solution of control problems, for investigation of interacting plants with environment and for training of speciaists has been realized. The interactive systems have been introduced in 8 enterprisesAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Statin therapy is associated with epigenetic modifications in individuals with Type 2 diabetes

Aim: Statins lower cholesterol and reduce the risk of cardiovascular disease. However, the exact mechanisms of statins remain unknown. We investigated whether statin therapy associates with epigenetics in Type 2 diabetes (T2D) patients. Materials & methods: DNA methylation was analyzed in blood from newly diagnosed T2D patients in All New Diabetics in Scania (ANDIS) and a replication cohort All New Diabetics in Uppsala County (ANDiU). Results: Seventy-nine sites were differentially methylated between cases on statins and controls (false discovery rate <5%) in ANDIS. These include previously statin-associated methylation sites annotated to DHCR24 (cg17901584), ABCG1 (cg27243685) and SC4MOL (cg05119988). Differential methylation of two sites related to cholesterol biosynthesis and immune response, cg17901584 (DHCR24) and cg23011663 (ARIH2), were replicated in ANDiU. Conclusion: Statin therapy associates with epigenetic modifications in T2D patients

Sex Differences in the Methylome and Transcriptome of the Human Liver and Circulating HDL-Cholesterol Levels

Context: Epigenetics may contribute to sex-specific differences in human liver metabolism. Objective: To study the impact of sex on DNA methylation and gene expression in human liver. Design/Setting: Cross-sectional, Kuopio Obesity Surgery Study. Participants/Intervention: We analyzed DNA methylation with the Infinium HumanMethylation450 BeadChip in liver of an obese population (34 males, 61 females). Females had a higher high-density lipoprotein (HDL)-cholesterol levels compared with males. Gene expression was measured with the HumanHT-12 Expression BeadChip in a subset of 42 participants. Results: Females displayed higher average methylation in the X-chromosome, whereas males presented higher methylation in autosomes. We found 9455 CpG sites in the X-chromosome and 33,205 sites in autosomes with significant methylation differences in liver between sexes (q < 0.05). When comparing our findings with published studies, 95% of the sex-specific differences in liver methylation in the X-chromosome were also found in pancreatic islets and brain, and 26 autosomal sites showed sex-specific methylation differences in the liver as well as in other human tissues. Furthermore, this sex-specific methylation profile in liver was associated with hepatic gene expression changes between males and females. Notably, females showed higher HDL-cholesterol levels, which were associated with higher KDM6A expression and epigenetic differences in human liver. Accordingly, silencing of KDM6A in cultured liver cells reduced HDL-cholesterol levels and APOA1 expression, which is a major component of HDL particles. Conclusions: Human liver has a sex-specific methylation profile in both the X-chromosome and autosomes, which associates with hepatic gene expression changes and HDL-cholesterol. We identified KDM6A as a novel target that regulates HDL-cholesterol levels

DNA methylation partially mediates antidiabetic effects of metformin on HbA1c levels in individuals with type 2 diabetes

Aims: Despite metformin being used as first-line pharmacological therapy for type 2 diabetes, its underlying mechanisms remain unclear. We aimed to determine whether metformin altered DNA methylation in newlydiagnosed individuals with type 2 diabetes. Methods and Results: We found that metformin therapy is associated with altered methylation of 26 sites in blood from Scandinavian discovery and replication cohorts (FDR &lt; 0.05), using MethylationEPIC arrays. The majority (88%) of these 26 sites were hypermethylated in patients taking metformin for similar to 3 months compared to controls, who had diabetes but had not taken any diabetes medication. Two of these blood-based methylation markers mirrored the epigenetic pattern in muscle and adipose tissue (FDR &lt; 0.05). Four type 2 diabetes-associated SNPs were annotated to genes with differential methylation between metformin cases and controls, e.g., GRB10, RPTOR, SLC22A18AS and TH2LCRR. Methylation correlated with expression in human islets for two of these genes. Three metformin-associated methylation sites (PKNOX2, WDTC1 and MICB) partially mediate effects of metformin on follow-up HbA1c levels. When combining methylation of these three sites into a score, which was used in a causal mediation analysis, methylation was suggested to mediate up to 32% of metformin's effects on HbA1c. Conclusion: Metformin-associated alterations in DNA methylation partially mediates metformin's antidiabetic effects on HbA1c in newly-diagnosed individuals with type 2 diabetes

Epigenetic alterations in blood mirror age-associated DNA methylation and gene expression changes in human liver

Aim: To study the impact of aging on DNA methylation and mRNA expression in human liver. Experimental procedures: We analysed genome-wide DNA methylation and gene expression in human liver samples using Illumina 450K and HumanHT12 expression BeadChip arrays. Results: DNA methylation analysis of ∼455,000 CpG sites in human liver revealed that age was significantly associated with altered DNA methylation of 20,396 CpG sites. Comparison of liver methylation data with published methylation data in other tissues showed that vast majority of the age-associated significant CpG sites overlapped between liver and blood, whereas a smaller overlap was found between liver and pancreatic islets or adipose tissue, respectively. We identified 151 genes whose liver expression also correlated with age. Conclusions: We identified age-associated DNA methylation and expression changes in human liver that are partly reflected by epigenetic alterations in blood