| 21. |
- Ling, Charlotte, et al.
(författare)
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Epigenetic adaptation to regular exercise in humans.
- 2014
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Ingår i: Drug Discovery Today. - : Elsevier BV. - 1878-5832 .- 1359-6446. ; 19:7, s. 1015-1018
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Forskningsöversikt (refereegranskat)abstract
- Regular exercise has numerous health benefits, for example, it reduces the risk of cardiovascular disease and cancer. It has also been shown that the risk of type 2 diabetes can be halved in high-risk groups through nonpharmacological lifestyle interventions involving exercise and diet. Nevertheless, the number of people living a sedentary life is dramatically increasing worldwide. Researchers have searched for molecular mechanisms explaining the health benefits of regular exercise for decades and it is well established that exercise alters the gene expression pattern in multiple tissues. However, until recently it was unknown that regular exercise can modify the genome-wide DNA methylation pattern in humans. This review will focus on recent progress in the field of regular exercise and epigenetics.
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| 22. |
- Ling, Charlotte, et al.
(författare)
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Epigenetic epidemiology and alterations in type 2 diabetes and obesity
- 2022
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Ingår i: Epigenetic epidemiology. - Cham : Springer International Publishing. - 9783030944759 - 9783030944742 ; , s. 445-474
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- ype 2 diabetes (T2D) and obesity are multifactorial and polygenic metabolic diseases. Combinations of genetic and non-genetic risk factors such as risk SNPs, age, unhealthy diets, and physical inactivity increase the risk for these diseases. Emerging data also support a key role for epigenetic mechanisms in the pathogenesis of T2D and obesity. In this chapter, we summarize current knowledge of epigenetic alterations found in individuals with T2D and obesity. We present studies performed in blood, as well as human tissues important for metabolism, i.e., adipose tissue, skeletal muscle, liver, and pancreatic islets. These studies have found differential DNA methylation associated with both T2D and obesity. Although some studies exist, there is still limited information regarding histone modifications in human tissues linked to metabolic diseases. We finally explore how epigenetic mechanisms may be targeted by epigenetic editing and inhibitors of epigenetic enzymes for future therapies and precision medicine in T2D and obesity.
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| 23. |
- Ling, Charlotte, et al.
(författare)
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Epigenetic markers to further understand insulin resistance
- 2016
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 59:11, s. 2295-2297
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Tidskriftsartikel (refereegranskat)abstract
- Epigenetic variation in human adipose tissue has been linked to type 2 diabetes and its related risk factors including age and obesity. Insulin resistance, a key risk factor for type 2 diabetes, may also be associated with altered DNA methylation in visceral and subcutaneous adipose tissue. Furthermore, linking epigenetic variation in target tissues to similar changes in blood cells may identify new blood-based biomarkers. In this issue of Diabetologia, Arner et al studied the transcriptome and methylome in subcutaneous and visceral adipose tissue of 80 obese women who were either insulin-sensitive or -resistant (DOI 10.1007/s00125-016-4074-5). While they found differences in gene expression between the two groups, no alterations in DNA methylation were found after correction for multiple testing. Nevertheless, based on nominal p values, their methylation data overlapped with methylation differences identified in adipose tissue of individuals with type 2 diabetes compared with healthy individuals. Differential methylation of these overlapping CpG sites may predispose to diabetes by occurring already in the insulin-resistant state. Furthermore, some methylation changes may contribute to an inflammatory process in adipose tissue since the identified CpG sites were annotated to genes encoding proteins involved in inflammation. Finally, the methylation pattern in circulating leucocytes did not mirror the adipose tissue methylome of these 80 women. Together, identifying novel molecular mechanisms contributing to insulin resistance and type 2 diabetes may help advance the search for new therapeutic alternatives.
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| 24. |
- Ling, Charlotte, et al.
(författare)
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Epigenetic regulation of PPARGC1A in human type 2 diabetic islets and effect on insulin secretion.
- 2008
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 51, s. 615-622
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Tidskriftsartikel (refereegranskat)abstract
- AIMS/HYPOTHESIS: Insulin secretion in pancreatic islets is dependent upon mitochondrial function and production of ATP. The transcriptional coactivator peroxisome proliferator activated receptor gamma coactivator-1 alpha (protein PGC-1alpha; gene PPARGC1A) is a master regulator of mitochondrial genes and its expression is decreased and related to impaired oxidative phosphorylation in muscle from patients with type 2 diabetes. Whether it plays a similar role in human pancreatic islets is not known. We therefore investigated if PPARGC1A expression is altered in islets from patients with type 2 diabetes and whether this expression is influenced by genetic (PPARGC1A Gly482Ser polymorphism) and epigenetic (DNA methylation) factors. We also tested if experimental downregulation of PPARGC1A expression in human islets influenced insulin secretion. METHODS: The PPARGC1A Gly482Ser polymorphism was genotyped in human pancreatic islets from 48 non-diabetic and 12 type 2 diabetic multi-organ donors and related to PPARGC1A mRNA expression. DNA methylation of the PPARGC1A promoter was analysed in pancreatic islets from ten type 2 diabetic and nine control donors. Isolated human islets were transfected with PPARGC1A silencing RNA (siRNA). RESULTS: PPARGC1A mRNA expression was reduced by 90% (p < 0.005) and correlated with the reduction in insulin secretion in islets from patients with type 2 diabetes. After downregulation of PPARGC1A expression in human islets by siRNA, insulin secretion was reduced by 41% (p
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| 25. |
- Ling, Charlotte, et al.
(författare)
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Epigenetics in Human Obesity and Type 2 Diabetes
- 2019
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Ingår i: Cell Metabolism. - : Elsevier BV. - 1550-4131. ; 29:5, s. 1028-1044
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Forskningsöversikt (refereegranskat)abstract
- Epigenetic mechanisms control gene activity and the development of an organism. The epigenome includes DNA methylation, histone modifications, and RNA-mediated processes, and disruption of this balance may cause several pathologies and contribute to obesity and type 2 diabetes (T2D). This Review summarizes epigenetic signatures obtained from human tissues of relevance for metabolism—i.e., adipose tissue, skeletal muscle, pancreatic islets, liver, and blood—in relation to obesity and T2D. Although this research field is still young, these comprehensive data support not only a role for epigenetics in disease development, but also epigenetic alterations as a response to disease. Genetic predisposition, as well as aging, contribute to epigenetic variability, and several environmental factors, including exercise and diet, further interact with the human epigenome. The reversible nature of epigenetic modifications holds promise for future therapeutic strategies in obesity and T2D. Epigenetic factors are suggested to contribute to metabolic dysfunctions. In this Review, Ling and Rönn summarize evidence for altered DNA methylation, both as a cause and a consequence of human obesity and type 2 diabetes. As epigenetic alterations are dynamic in nature, they may also provide targets for drug development.
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| 26. |
- Ling, Charlotte, et al.
(författare)
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Epigenetics of type 2 diabetes mellitus and weight change — a tool for precision medicine?
- 2022
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Ingår i: Nature Reviews Endocrinology. - : Springer Science and Business Media LLC. - 1759-5029 .- 1759-5037. ; 18:7, s. 433-448
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Forskningsöversikt (refereegranskat)abstract
- Pioneering studies performed over the past few decades demonstrate links between epigenetics and type 2 diabetes mellitus (T2DM), the metabolic disorder with the most rapidly increasing prevalence in the world. Importantly, these studies identified epigenetic modifications, including altered DNA methylation, in pancreatic islets, adipose tissue, skeletal muscle and the liver from individuals with T2DM. As non-genetic factors that affect the risk of T2DM, such as obesity, unhealthy diet, physical inactivity, ageing and the intrauterine environment, have been associated with epigenetic modifications in healthy individuals, epigenetics probably also contributes to T2DM development. In addition, genetic factors associated with T2DM and obesity affect the epigenome in human tissues. Notably, causal mediation analyses found DNA methylation to be a potential mediator of genetic associations with metabolic traits and disease. In the past few years, translational studies have identified blood-based epigenetic markers that might be further developed and used for precision medicine to help patients with T2DM receive optimal therapy and to identify patients at risk of complications. This Review focuses on epigenetic mechanisms in the development of T2DM and the regulation of body weight in humans, with a special focus on precision medicine.
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| 27. |
- Ling, Charlotte, et al.
(författare)
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Genetic and epigenetic factors are associated with expression of respiratory chain component NDUFB6 in human skeletal muscle.
- 2007
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Ingår i: The Journal of clinical investigation. - 0021-9738. ; 117:11, s. 3427-35
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Tidskriftsartikel (refereegranskat)abstract
- Insulin resistance and type 2 diabetes are associated with decreased expression of genes that regulate oxidative phosphorylation in skeletal muscle. To determine whether this defect might be inherited or acquired, we investigated the association of genetic, epigenetic, and nongenetic factors with expression of NDUFB6, a component of the respiratory chain that is decreased in muscle from diabetic patients. Expression of NDUFB6 was influenced by age, with lower gene expression in muscle of elderly subjects. Heritability of NDUFB6 expression in muscle was estimated to be approximately 60% in twins. A polymorphism in the NDUFB6 promoter region that creates a possible DNA methylation site (rs629566, A/G) was associated with a decline in muscle NDUFB6 expression with age. Although young subjects with the rs629566 G/G genotype exhibited higher muscle NDUFB6 expression, this genotype was associated with reduced expression in elderly subjects. This was subsequently explained by the finding of increased DNA methylation in the promoter of elderly, but not young, subjects carrying the rs629566 G/G genotype. Furthermore, the degree of DNA methylation correlated negatively with muscle NDUFB6 expression, which in turn was associated with insulin sensitivity. Our results demonstrate that genetic, epigenetic, and nongenetic factors associate with NDUFB6 expression in human muscle and suggest that genetic and epigenetic factors may interact to increase age-dependent susceptibility to insulin resistance.
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| 28. |
- Ling, Charlotte, et al.
(författare)
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Genome-Wide DNA and Histone Modification Studies in Metabolic Disease
- 2015
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Ingår i: Epigenomics in Health and Disease. - 9780128001400 - 9780128004968 ; , s. 255-270
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Bokkapitel (refereegranskat)abstract
- The last decade has witnessed a revolution in genetic technology, where genome-wide analyses, covering the majority of genetic variation, were thought to explain disease-causing mechanisms in common metabolic disorders. However, these genetic data only explain a modest proportion of the estimated heritability of type 2 diabetes and obesity and hence suggest a potential role for epigenetic variation in the etiology of metabolic disease. Indeed, recent genome-wide epigenetic studies have identified altered DNA methylation patterns in human pancreatic islets, adipose tissue, skeletal muscle, and blood from subjects with type 2 diabetes compared with normal subjects. Also, measures of obesity, such as increased body mass index (BMI), have been associated with epigenetic modifications in humans. It should also be noted that environmental risk factors for metabolic disease, for example, energy-rich diets, physical inactivity, and aging have been found to alter the epigenetic pattern genome-wide and in candidate genes for type 2 diabetes and obesity in human tissues. Additionally, interactions between genetic and epigenetic variations seem to contribute to the risk for metabolic disease. Together, genome-wide epigenetic studies highlight the importance of altered DNA methylation and histone modifications in the pathogenesis of metabolic disease. This chapter aims at summarizing current knowledge in the field of metabolic disease and genome-wide epigenetic analyses in humans.
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| 29. |
- Nilsson, Emma A, et al.
(författare)
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Altered DNA Methylation and Differential Expression of Genes Influencing Metabolism and Inflammation in Adipose Tissue From Subjects With Type 2 Diabetes
- 2014
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 63:9, s. 2962-2976
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Tidskriftsartikel (refereegranskat)abstract
- Genetics, epigenetics, and environment may together affect the susceptibility for type 2 diabetes (T2D). Our aim was to dissect molecular mechanisms underlying T2D using genome-wide expression and DNA methylation data in adipose tissue from monozygotic twin pairs discordant for T2D and independent case-control cohorts. In adipose tissue from diabetic twins, we found decreased expression of genes involved in oxidative phosphorylation; carbohydrate, amino acid, and lipid metabolism; and increased expression of genes involved in inflammation and glycan degradation. The most differentially expressed genes included ELOVL6, GYS2, FADS1, SPP1 (OPN), CCL18, and IL1RN. We replicated these results in adipose tissue from an independent case-control cohort. Several candidate genes for obesity and T2D (e.g., IRS1 and VEGFA) were differentially expressed in discordant twins. We found a heritable contribution to the genome-wide DNA methylation variability in twins. Differences in methylation between monozygotic twin pairs discordant for T2D were subsequently modest. However, 15,627 sites, representing 7,046 genes including PPARG, KCNQ1, TCF7L2, and IRS1, showed differential DNA methylation in adipose tissue from unrelated subjects with T2D compared with control subjects. A total of 1,410 of these sites also showed differential DNA methylation in the twins discordant for T2D. For the differentially methylated sites, the heritability estimate was 0.28. We also identified copy number variants (CNVs) in monozygotic twin pairs discordant for T2D. Taken together, subjects with T2D exhibit multiple transcriptional and epigenetic changes in adipose tissue relevant to the development of the disease.
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| 30. |
- Olsson, Anders H, et al.
(författare)
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Genome-Wide Associations between Genetic and Epigenetic Variation Influence mRNA Expression and Insulin Secretion in Human Pancreatic Islets.
- 2014
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 10:11
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Tidskriftsartikel (refereegranskat)abstract
- Genetic and epigenetic mechanisms may interact and together affect biological processes and disease development. However, most previous studies have investigated genetic and epigenetic mechanisms independently, and studies examining their interactions throughout the human genome are lacking. To identify genetic loci that interact with the epigenome, we performed the first genome-wide DNA methylation quantitative trait locus (mQTL) analysis in human pancreatic islets. We related 574,553 single nucleotide polymorphisms (SNPs) with genome-wide DNA methylation data of 468,787 CpG sites targeting 99% of RefSeq genes in islets from 89 donors. We identified 67,438 SNP-CpG pairs in cis, corresponding to 36,783 SNPs (6.4% of tested SNPs) and 11,735 CpG sites (2.5% of tested CpGs), and 2,562 significant SNP-CpG pairs in trans, corresponding to 1,465 SNPs (0.3% of tested SNPs) and 383 CpG sites (0.08% of tested CpGs), showing significant associations after correction for multiple testing. These include reported diabetes loci, e.g. ADCY5, KCNJ11, HLA-DQA1, INS, PDX1 and GRB10. CpGs of significant cis-mQTLs were overrepresented in the gene body and outside of CpG islands. Follow-up analyses further identified mQTLs associated with gene expression and insulin secretion in human islets. Causal inference test (CIT) identified SNP-CpG pairs where DNA methylation in human islets is the potential mediator of the genetic association with gene expression or insulin secretion. Functional analyses further demonstrated that identified candidate genes (GPX7, GSTT1 and SNX19) directly affect key biological processes such as proliferation and apoptosis in pancreatic β-cells. Finally, we found direct correlations between DNA methylation of 22,773 (4.9%) CpGs with mRNA expression of 4,876 genes, where 90% of the correlations were negative when CpGs were located in the region surrounding transcription start site. Our study demonstrates for the first time how genome-wide genetic and epigenetic variation interacts to influence gene expression, islet function and potential diabetes risk in humans.
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