| 1. |
- de Mello, Vanessa D., et al.
(författare)
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Indolepropionic acid and novel lipid metabolites are associated with a lower risk of type 2 diabetes in the Finnish Diabetes Prevention Study
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Wide-scale profiling technologies including metabolomics broaden the possibility of novel discoveries related to the pathogenesis of type 2 diabetes (T2D). By applying non-targeted metabolomics approach, we investigated here whether serum metabolite profile predicts T2D in a well-characterized study population with impaired glucose tolerance by examining two groups of individuals who took part in the Finnish Diabetes Prevention Study (DPS); those who either early developed T2D (n = 96) or did not convert to T2D within the 15-year follow-up (n = 104). Several novel metabolites were associated with lower likelihood of developing T2D, including indole and lipid related metabolites. Higher indolepropionic acid was associated with reduced likelihood of T2D in the DPS. Interestingly, in those who remained free of T2D, indolepropionic acid and various lipid species were associated with better insulin secretion and sensitivity, respectively. Furthermore, these metabolites were negatively correlated with low-grade inflammation. We replicated the association between indolepropionic acid and T2D risk in one Finnish and one Swedish population. We suggest that indolepropionic acid, a gut microbiota-produced metabolite, is a potential biomarker for the development of T2D that may mediate its protective effect by preservation of alpha-cell function. Novel lipid metabolites associated with T2D may exert their effects partly through enhancing insulin sensitivity.
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| 2. |
- Kolehmainen, Marjukka, et al.
(författare)
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Healthy Nordic diet downregulates the expression of genes involved in inflammation in subcutaneous adipose tissue in individuals with features of the metabolic syndrome.
- 2015
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 101:1, s. 228-239
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Previously, a healthy Nordic diet (ND) has been shown to have beneficial health effects close to those of Mediterranean diets.OBJECTIVE: The objective was to explore whether the ND has an impact on gene expression in abdominal subcutaneous adipose tissue (SAT) and whether changes in gene expression are associated with clinical and biochemical effects.DESIGN: Obese adults with features of the metabolic syndrome underwent an 18- to 24-wk randomized intervention study comparing the ND with the control diet (CD) (the SYSDIET study, carried out within Nordic Centre of Excellence of the Systems Biology in Controlled Dietary Interventions and Cohort Studies). The present study included participants from 3 Nordic SYSDIET centers [Kuopio (n = 20), Lund (n = 18), and Oulu (n = 18)] with a maximum weight change of ±4 kg, highly sensitive C-reactive protein concentration <10 mg/L at the beginning and the end of the intervention, and baseline body mass index (in kg/m(2)) <38. SAT biopsy specimens were obtained before and after the intervention and subjected to global transcriptome analysis with Gene 1.1 ST Arrays (Affymetrix).RESULTS: Altogether, 128 genes were differentially expressed in SAT between the ND and CD (nominal P < 0.01; false discovery rate, 25%). These genes were overrepresented in pathways related to immune response (adjusted P = 0.0076), resulting mainly from slightly decreased expression in the ND and increased expression in the CD. Immune-related pathways included leukocyte trafficking and macrophage recruitment (e.g., interferon regulatory factor 1, CD97), adaptive immune response (interleukin32, interleukin 6 receptor), and reactive oxygen species (neutrophil cytosolic factor 1). Interestingly, the regulatory region of the 128 genes was overrepresented for binding sites for the nuclear transcription factor κB.CONCLUSION: A healthy Nordic diet reduces inflammatory gene expression in SAT compared with a control diet independently of body weight change in individuals with features of the metabolic syndrome. The study was registered at clinicaltrials.gov as NCT00992641.
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| 3. |
- Ahlqvist, Emma, et al.
(författare)
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A link between GIP and osteopontin in adipose tissue and insulin resistance.
- 2013
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 62:6, s. 2088-2094
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Tidskriftsartikel (refereegranskat)abstract
- Low grade inflammation in obesity is associated with accumulation of the macrophagederived cytokine osteopontin in adipose tissue and induction of local as well as systemic insulin resistance. Since GIP (glucose-dependent insulinotropic polypeptide) is a strong stimulator of adipogenesis and may play a role in the development of obesity, we explored whether GIP directly would stimulate osteopontin (OPN) expression in adipose tissue and thereby induce insulin resistance. GIP stimulated OPN protein expression in a dose-dependent fashion in rat primary adipocytes. The level of OPN mRNA was higher in adipose tissue of obese individuals (0.13±}0.04 vs 0.04±}0.01, P<0.05) and correlated inversely with measures of insulin sensitivity (r=-0.24, P=0.001). A common variant of the GIP receptor (GIPR) (rs10423928) gene was associated with lower amount of the exon 9 containing isoform required for transmembrane activity. Carriers of the A-allele with a reduced receptor function showed lower adipose tissue OPN mRNA levels and better insulin sensitivity. Together, these data suggest a role for GIP not only as an incretin hormone, but also as a trigger of inflammation and insulin resistance in adipose tissue. Carriers of GIPR rs10423928 A-allele showed protective properties via reduced GIP effects. Identification of this unprecedented link between GIP and OPN in adipose tissue might open new avenues for therapeutic interventions.
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| 4. |
- Baumeier, Christian, et al.
(författare)
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Hepatic DPP4 DNA methylation associates with fatty liver
- 2017
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 66:1, s. 25-35
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Bysani, Madhusudhan, et al.
(författare)
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Epigenetic alterations in blood mirror age-associated DNA methylation and gene expression changes in human liver
- 2017
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Ingår i: Epigenomics. - : Future Medicine Ltd. - 1750-1911 .- 1750-192X. ; 9:2, s. 105-122
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 6. |
- Cardona, Alexia, et al.
(författare)
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Epigenome-wide association study of incident type 2 diabetes in a British population : EPIC-Norfolk study
- 2019
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 68:12, s. 2315-2326
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Tidskriftsartikel (refereegranskat)abstract
- 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 populationbased 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 obesityrelated 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.
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| 7. |
- Dayeh, Tasnim, et al.
(författare)
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DNA methylation of loci within ABCG1 and PHOSPHO1 in blood DNA is associated with future type 2 diabetes risk
- 2016
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Ingår i: Epigenetics. - : Informa UK Limited. - 1559-2294 .- 1559-2308. ; 11:7, s. 482-488
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- de Mello, Vanessa D., et al.
(författare)
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Serum aromatic and branched-chain amino acids associated with NASH demonstrate divergent associations with serum lipids
- 2021
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Ingår i: Liver International. - : Wiley. - 1478-3223 .- 1478-3231. ; 41:4, s. 754-763
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Non-alcoholic fatty liver disease (NAFLD) has been associated with multiple metabolic abnormalities. By applying a non-targeted metabolomics approach, we aimed at investigating whether serum metabolite profile that associates with NAFLD would differ in its association with NAFLD-related metabolic risk factors. Methods & Results: A total of 233 subjects (mean ± SD: 48.3 ± 9.3 years old; BMI: 43.1 ± 5.4 kg/m2; 64 male) undergoing bariatric surgery were studied. Of these participants, 164 with liver histology could be classified as normal liver (n = 79), simple steatosis (SS, n = 40) or non-alcoholic steatohepatitis (NASH, n = 45). Among the identified fasting serum metabolites with higher levels in those with NASH when compared to those with normal phenotype were the aromatic amino acids (AAAs: tryptophan, tyrosine and phenylalanine), the branched-chain amino acids (BCAAs: leucine and isoleucine), a phosphatidylcholine (PC(16:0/16:1)) and uridine (all FDRp < 0.05). Only tryptophan was significantly higher in those with NASH compared to those with SS (FDRp < 0.05). Only the AAAs tryptophan and tyrosine correlated positively with serum total and LDL cholesterol (FDRp < 0.1), and accordingly, with liver LDLR at mRNA expression level. In addition, tryptophan was the single AA associated with liver DNA methylation of CpG sites known to be differentially methylated in those with NASH. Conclusions: We found that serum levels of the NASH-related AAAs and BCAAs demonstrate divergent associations with serum lipids. The specific correlation of tryptophan with LDL-c may result from the molecular events affecting LDLR mRNA expression and NASH-associated methylation of genes in the liver.
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| 9. |
- de Mello, Vanessa, et al.
(författare)
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Human liver epigenetic alterations in non-alcoholic steatohepatitis are related to insulin action
- 2017
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Ingår i: Epigenetics. - : Informa UK Limited. - 1559-2294 .- 1559-2308. ; 12:4, s. 287-295
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Tidskriftsartikel (refereegranskat)abstract
- Both genetic and lifestyle factors contribute to the risk of non-alcoholic steatohepatitis (NASH). Additionally, epigenetic modifications may also play a key role in the pathogenesis of NASH. We therefore investigated liver DNA methylation, as a marker for epigenetic alterations, in individuals with simple steatosis and NASH, and further tested if these alterations were associated with clinical phenotypes. Liver biopsies obtained from 95 obese individuals (age: 49.5 ± 7.7 years, BMI: 43 ± 5.7 kg/m2, type 2 diabetes [T2D]: 35) as a wedge biopsy during a Roux-en-Y gastric bypass operation were investigated. Thirty-four individuals had a normal liver phenotype, 35 had simple steatosis, and 26 had NASH. Genome-wide DNA methylation pattern was analyzed using the Infinium HumanMethylation450 BeadChip. mRNA expression was analyzed from 42 individuals using the HumanHT-12 Expression BeadChip. We identified 1,292 CpG sites representing 677 unique genes differentially methylated in liver of individuals with NASH (q < 0.001), independently of T2D, age, sex, and BMI. Focusing on the top-ranking 30 and another 37 CpG sites mapped to genes enriched in pathways of metabolism (q = 0.0036) and cancer (q = 0.0001) all together, 59 NASH-associated CpG sites correlated with fasting insulin levels independently of age, fasting glucose, or T2D. From these, we identified 30 correlations between DNA methylation and mRNA expression, for example LDHB (r = −0.45, P = 0.003). We demonstrated that NASH, more than simple steatosis, associates with differential DNA methylation in the human liver. These epigenetic alterations in NASH are linked with insulin metabolism.
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| 10. |
- Dongiovanni, Paola, et al.
(författare)
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Protein phosphatase 1 regulatory subunit 3B gene variation protects against hepatic fat accumulation and fibrosis in individuals at high risk of nonalcoholic fatty liver disease.
- 2018
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Ingår i: Hepatology communications. - : Ovid Technologies (Wolters Kluwer Health). - 2471-254X. ; 2:6, s. 666-675
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Tidskriftsartikel (refereegranskat)abstract
- Nonalcoholic fatty liver disease (NAFLD) is a major cause of liver damage and has a strong genetic component. The rs4841132 G>A variant, modulating the expression of protein phosphatase 1 regulatory subunit 3B (PPP1R3B), which is involved in glycogen synthesis, has been reported to reduce the risk of NAFLD but at the same time may favor liver disease by facilitating glycogen accumulation. The aim of this study was to assess the impact of rs4841132 on development of histologic steatosis and fibrosis in 1,388 European individuals in a liver biopsy cohort, on NAFLD hepatocellular carcinoma in a cross-sectional Italian cohort (n = 132 cases), and on liver disease at the population level in the United Kingdom Biobank cohort. We investigated the underlying mechanism by examining the impact of the variant on gene expression profiles. In the liver biopsy cohort, the rs4841132 minor A allele was associated with protection against steatosis (odds ratio [OR], 0.63; 95% confidence interval [CI], 0.42-0.95; P = 0.03) and clinically significant fibrosis (OR, 0.35; 95% CI, 0.14-0.87; P = 0.02) and with reduced circulating cholesterol (P = 0.02). This translated into protection against hepatocellular carcinoma development (OR, 0.22; 95% CI, 0.07-0.70; P = 0.01). At the population level, the rs4841132 variation was not associated with nonalcoholic or nonviral diseases of the liver but was associated with lower cholesterol (P = 1.7 × 10-8). In individuals with obesity, the A allele protecting against steatosis was associated with increased PPP1R3B messenger RNA expression and activation of lipid oxidation and with down-regulation of pathways related to lipid metabolism, inflammation, and cell cycle. Conclusion: The rs4841132 A allele is associated with protection against hepatic steatosis and fibrosis in individuals at high risk of NAFLD but not in the general population and against dyslipidemia. The mechanism may be related to modulation of PPP1R3B expression and hepatic lipid metabolism. (Hepatology Communications 2018;2:666-675).
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