| 21. |
- Bacos, Karl, et al.
(author)
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Blood-based biomarkers of age-associated epigenetic changes in human islets associate with insulin secretion and diabetes
- 2016
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Journal article (peer-reviewed)abstract
- Aging associates with impaired pancreatic islet function and increased type 2 diabetes (T2D) risk. Here we examine whether age-related epigenetic changes affect human islet function and if blood-based epigenetic biomarkers reflect these changes and associate with future T2D. We analyse DNA methylation genome-wide in islets from 87 non-diabetic donors, aged 26-74 years. Aging associates with increased DNA methylation of 241 sites. These sites cover loci previously associated with T2D, for example, KLF14. Blood-based epigenetic biomarkers reflect age-related methylation changes in 83 genes identified in human islets (for example, KLF14, FHL2, ZNF518B and FAM123C) and some associate with insulin secretion and T2D. DNA methylation correlates with islet expression of multiple genes, including FHL2, ZNF518B, GNPNAT1 and HLTF. Silencing these genes in β-cells alter insulin secretion. Together, we demonstrate that blood-based epigenetic biomarkers reflect age-related DNA methylation changes in human islets, and associate with insulin secretion in vivo and T2D.
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| 22. |
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| 23. |
- Bacos, Karl, et al.
(author)
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Type 2 diabetes candidate genes, including PAX5, cause impaired insulin secretion in human pancreatic islets
- 2023
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In: The Journal of clinical investigation. - 0021-9738 .- 1558-8238. ; 133:4
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Journal article (peer-reviewed)abstract
- Type 2 diabetes (T2D) is caused by insufficient insulin secretion from pancreatic β-cells. To identify candidates contributing to T2D pathophysiology, we studied human pancreatic islets from ~300 individuals. We found 395 differentially expressed genes (DEGs) in islets from individuals with T2D, including, to our knowledge, novel (OPRD1, PAX5, TET1) and previously identified (CHL1, GLRA1, IAPP) candidates. A third of the identified islet expression changes may predispose to diabetes, as they associated with HbA1c in individuals not previously diagnosed with T2D. Most DEGs were expressed in human β-cells based on single-cell RNA-sequencing data. Additionally, DEGs displayed alterations in open chromatin and associated with T2D-SNPs. Mouse knock-out strains demonstrated that T2D-associated candidates regulate glucose homeostasis and body composition in vivo. Functional validation showed that mimicking T2D-associated changes for OPRD1, PAX5, and SLC2A2 impaired insulin secretion. Impairments in Pax5-overexpressing β-cells were due to severe mitochondrial dysfunction. Finally, we discovered PAX5 as a potential transcriptional regulator of many T2D-associated DEGs in human islets. Overall, we identified molecular alterations in human pancreatic islets contributing to β-cell dysfunction in T2D pathophysiology.
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| 24. |
- Baumeier, Christian, et al.
(author)
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Hepatic DPP4 DNA methylation associates with fatty liver
- 2017
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In: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 66:1, s. 25-35
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Journal article (peer-reviewed)abstract
- Hepatic DPP4 expression is elevated in subjects with ectopic fat accumulation in the liver. However, whether increased dipeptidyl peptidase 4 (DPP4) is involved in the pathogenesis or is rather a consequence ofmetabolic disease is not known. We therefore studied the transcriptional regulation of hepatic Dpp4 in young mice prone to diet-induced obesity. Already at 6 weeks of age, expression of hepatic Dpp4 was increased in mice with high weight gain, independent of liver fat content. In the same animals, methylation of four intronic CpG sites was decreased, amplifying glucose-induced transcription of hepatic Dpp4. In older mice, hepatic triglyceride content was increased only in animals with elevated Dpp4 expression. Expression and release of DPP4 were markedly higher in the liver compared with adipose depots. Analysis of human liver biopsy specimens revealed a correlation of DPP4 expression and DNA methylation to stages of hepatosteatosis and nonalcoholic steatohepatitis. In summary, our results indicate a crucial role of the liver in participation to systemic DPP4 levels. Furthermore, the data show that glucoseinduced expression of Dpp4 in the liver is facilitated by demethylation of the Dpp4 gene early in life. This might contribute to early deteriorations in hepatic function, which in turn result in metabolic disease such as hepatosteatosis later in life.
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| 25. |
- Benrick, Anna, 1979, et al.
(author)
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Electroacupuncture mimics exercise-induced changes in skeletal muscle gene expression in polycystic ovary syndrome women.
- 2020
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 105:6, s. 2027-2041
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Journal article (peer-reviewed)abstract
- Autonomic nervous system activation mediates the increase in whole-body glucose uptake in response to electroacupuncture but the mechanisms are largely unknown.To identify the molecular mechanisms underlying electroacupuncture-induced glucose uptake in skeletal muscle in insulin-resistant overweight/obese women with and without polycystic ovary syndrome (PCOS).Participants: In a case-control study, skeletal muscle biopsies were collected from 15 women with PCOS and 14 controls before and after electroacupuncture. Gene expression and methylation was analyzed using Illumina BeadChips arrays.A single bout of electroacupuncture restores metabolic and transcriptional alterations and induces epigenetic changes in skeletal muscle. Transcriptomic analysis revealed 180 unique genes (q<0.05) whose expression was changed by electroacupuncture, with 95% of the changes towards a healthier phenotype. We identified DNA methylation changes at 304 unique sites (q<0.20), and these changes correlated with altered expression of 101 genes (p<0.05). Among the 50 most upregulated genes in response to electroacupuncture, 38% were also upregulated in response to exercise. We identified a subset of genes that were selectively altered by electroacupuncture in women with PCOS. For example, MSX1 and SRNX1 were decreased in muscle tissue of women with PCOS and were increased by electroacupuncture and exercise. siRNA-mediated silencing of these two genes in cultured myotubes decreased glycogen synthesis, supporting a role for these genes in glucose homeostasis.Our findings provide evidence that electroacupuncture normalizes gene expression in skeletal muscle in a manner similar to acute exercise. Electroacupuncture might therefore be a useful way of assisting those who have difficulties performing exercise.
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| 26. |
- Benrick, Anna, 1979-, et al.
(author)
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Electroacupuncture mimics exercise-induced changes in skeletal muscle gene expression in women with polycystic ovary syndrome
- 2020
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In: Journal of Clinical Endocrinology and Metabolism. - : Oxford University Press. - 0021-972X .- 1945-7197. ; 105:6, s. 2027-2041
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Journal article (peer-reviewed)abstract
- ContextAutonomic nervous system activation mediates the increase in whole-body glucose uptake in response to electroacupuncture but the mechanisms are largely unknown.ObjectiveTo identify the molecular mechanisms underlying electroacupuncture-induced glucose uptake in skeletal muscle in insulin-resistant overweight/obese women with and without polycystic ovary syndrome (PCOS).Design/ParticipantsIn a case-control study, skeletal muscle biopsies were collected from 15 women with PCOS and 14 controls before and after electroacupuncture. Gene expression and methylation was analyzed using Illumina BeadChips arrays.ResultsA single bout of electroacupuncture restores metabolic and transcriptional alterations and induces epigenetic changes in skeletal muscle. Transcriptomic analysis revealed 180 unique genes (q < 0.05) whose expression was changed by electroacupuncture, with 95% of the changes towards a healthier phenotype. We identified DNA methylation changes at 304 unique sites (q < 0.20), and these changes correlated with altered expression of 101 genes (P < 0.05). Among the 50 most upregulated genes in response to electroacupuncture, 38% were also upregulated in response to exercise. We identified a subset of genes that were selectively altered by electroacupuncture in women with PCOS. For example, MSX1 and SRNX1 were decreased in muscle tissue of women with PCOS and were increased by electroacupuncture and exercise. siRNA-mediated silencing of these 2 genes in cultured myotubes decreased glycogen synthesis, supporting a role for these genes in glucose homeostasis.ConclusionOur findings provide evidence that electroacupuncture normalizes gene expression in skeletal muscle in a manner similar to acute exercise. Electroacupuncture might therefore be a useful way of assisting those who have difficulties performing exercise.
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| 27. |
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| 28. |
- Boström, Pontus, 1982, et al.
(author)
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The SNARE protein SNAP23 and the SNARE-interacting protein Munc18c in human skeletal muscle are implicated in insulin resistance/type 2 diabetes.
- 2010
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In: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 59:8, s. 1870-8
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Our previous studies suggest that the SNARE protein synaptosomal-associated protein of 23 kDa (SNAP23) is involved in the link between increased lipid levels and insulin resistance in cardiomyocytes. The objective was to determine whether SNAP23 may also be involved in the known association between lipid accumulation in skeletal muscle and insulin resistance/type 2 diabetes in humans, as well as to identify a potential regulator of SNAP23. RESEARCH DESIGN AND METHODS: We analyzed skeletal muscle biopsies from patients with type 2 diabetes and healthy, insulin-sensitive control subjects for expression (mRNA and protein) and intracellular localization (subcellular fractionation and immunohistochemistry) of SNAP23, and for expression of proteins known to interact with SNARE proteins. Insulin resistance was determined by a euglycemic hyperinsulinemic clamp. Potential mechanisms for regulation of SNAP23 were also investigated in the skeletal muscle cell line L6. RESULTS: We showed increased SNAP23 levels in skeletal muscle from patients with type 2 diabetes compared with that from lean control subjects. Moreover, SNAP23 was redistributed from the plasma membrane to the microsomal/cytosolic compartment in the patients with the type 2 diabetes. Expression of the SNARE-interacting protein Munc18c was higher in skeletal muscle from patients with type 2 diabetes. Studies in L6 cells showed that Munc18c promoted the expression of SNAP23. CONCLUSIONS: We have translated our previous in vitro results into humans by showing that there is a change in the distribution of SNAP23 to the interior of the cell in skeletal muscle from patients with type 2 diabetes. We also showed that Munc18c is a potential regulator of SNAP23.
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| 29. |
- Bray, Molly S, et al.
(author)
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NIH working group report-using genomic information to guide weight management: From universal to precision treatment.
- 2016
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In: Obesity. - : Wiley. - 1930-739X .- 1930-7381. ; 24:1, s. 14-22
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Research review (peer-reviewed)abstract
- Precision medicine utilizes genomic and other data to optimize and personalize treatment. Although more than 2,500 genetic tests are currently available, largely for extreme and/or rare phenotypes, the question remains whether this approach can be used for the treatment of common, complex conditions like obesity, inflammation, and insulin resistance, which underlie a host of metabolic diseases.
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| 30. |
- Broholm, Christa, et al.
(author)
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Epigenetic programming of adipose-derived stem cells in low birthweight individuals
- 2016
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In: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 59:12, s. 2664-2673
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Journal article (peer-reviewed)abstract
- Aims/hypothesis: Low birthweight (LBW) is associated with dysfunctions of adipose tissue and metabolic disease in adult life. We hypothesised that altered epigenetic and transcriptional regulation of adipose-derived stem cells (ADSCs) could play a role in programming adipose tissue dysfunction in LBW individuals. Methods: ADSCs were isolated from the subcutaneous adipose tissue of 13 normal birthweight (NBW) and 13 LBW adult men. The adipocytes were cultured in vitro, and genome-wide differences in RNA expression and DNA methylation profiles were analysed in ADSCs and differentiated adipocytes. Results: We demonstrated that ADSCs from LBW individuals exhibit multiple expression changes as well as genome-wide alterations in methylation pattern. Reduced expression of the transcription factor cyclin T2 encoded by CCNT2 may play a key role in orchestrating several of the gene expression changes in ADSCs from LBW individuals. Indeed, silencing of CCNT2 in human adipocytes decreased leptin secretion as well as the mRNA expression of several genes involved in adipogenesis, including MGLL, LIPE, PPARG, LEP and ADIPOQ. Only subtle genome-wide mRNA expression and DNA methylation changes were seen in mature cultured adipocytes from LBW individuals. Conclusions/interpretation: Epigenetic and transcriptional changes in LBW individuals are most pronounced in immature ADSCs that in turn may programme physiological characteristics of the mature adipocytes that influence the risk of metabolic diseases. Reduced expression of CCNT2 may play a key role in the developmental programming of adipose tissue.
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