Integrative genomic analyses in adipocytes implicate DNA methylation in human obesity and diabetes
Ontology highlight
ABSTRACT:
PROVIDER: EGAS00001007118 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:DNA methylation variations are prevalent in human obesity but evidence of a causative role in disease pathogenesis is limited. Here, we combine epigenome-wide association and integrative genomics to investigate the impact of adipocyte DNA methylation variations in human obesity. We discover extensive DNA methylation changes that are robustly associated with obesity (N=190 samples, 691 loci in subcutaneous and 173 loci in visceral adipocytes, P<1x10-7). We connect obesity-associated methylation variations to transcriptomic changes at >500 target genes, and identify putative methylation-transcription factor interactions. Through Mendelian Randomisation, we infer causal effects of methylation on obesity and obesity-induced metabolic disturbances at 59 independent loci. Targeted methylation sequencing, CRISPR-activation and gene silencing in adipocytes, further identifies regional methylation variations, underlying regulatory elements and novel cellular metabolic effects. Our results indicate DNA methylation is an important determinant of human obesity and its metabolic complications, and reveal mechanisms through which altered methylation may impact adipocyte functions.
2023-04-14 | GSE222595 | GEO
Project description:White adipose tissue (WAT) is a key regulator of systemic energy metabolism, and impaired WAT plasticity characterized by enlargement of preexisting adipocytes associates with WAT dysfunction, obesity and metabolic complications. However, the mechanisms that retain proper adipose tissue plasticity required for metabolic fitness are unclear. Here, we comprehensively showed that adipocyte-specific DNA methylation, manifested in enhancers and CTCF sites, directs distal enhancer-mediated transcriptomic features required to conserve metabolic functions of white adipocytes. Particularly, genetic ablation of adipocyte Dnmt1, the major methylation writer, led to increased adiposity characterized by increased adipocyte hypertrophy along with reduced expansion of adipocyte precursors (APs). These effects of Dnmt1 deficiency provoked systemic hyperlipidemia and impaired energy metabolism both in lean and obese mice. Mechanistically, Dnmt1 deficiency abrogated mitochondrial bioenergetics by inhibiting mitochondrial fission and promoted aberrant lipid metabolism in adipocytes, rendering adipocyte hypertrophy and WAT dysfunction. Dnmt1-dependent DNA methylation prevented aberrant CTCF binding and, in turn, sustained the proper chromosome architecture to permit interactions between enhancer and dynamin-related protein gene Drp1 in adipocytes. Also, adipose DNMT1 expression inversely correlated with adiposity and markers of metabolic health, but positively correlated with AP-specific markers in obese human subjects. Thus, these findings support strategies utilizing Dnmt1 action on mitochondrial bioenergetics in adipocytes to combat obesity and related metabolic pathology.
2021-03-24 | GSE158944 | GEO
Project description:Obesity is considered an important factor for many chronic diseases, including diabetes, cardiovascular disease and cancer. The expansion of adipose tissue in obesity is due to an increase in both adipocyte progenitor differentiation and mature adipocyte cell size. Adipocytes, however, are thought to be unable to divide or enter cell cycle. We demonstrate that mature human adipocytes unexpectedly display a gene and protein signature of cell cycle re-entry. Adipocyte cell cycle progression associates with obesity and hyperinsulinemia, with a concomitant increase in cell size, nuclear size and nuclear DNA content. However, chronic hyperinsulinemia in vitro or in patients, is associated with subsequent cell cycle exit, leading to a premature senescent transcriptomic and secretory profile in adipocytes. Premature senescence is rapidly becoming recognized as an important mediator of stress-induced tissue dysfunction. By demonstrating that adipocytes can re-enter cell cycle we define a mechanism for how mature, human adipocytes senesce and demonstrate that by targeting the adipocyte cell cycle program it is possible to impact adipocyte senescence and obesity-associated adipose tissue inflammation.
| EGAS00001005770 | EGA
Project description:Obesity is characterized by excess energy storage which results in dysfunctional white adipose tissue (WAT) and in turn leads to metabolic diseases. Lifestyle changes especially calorie restriction (CR) reduces the risk for age and obesity-associated complications. The impact of CR on obesity has mainly been examined with human intervention studies, which indicated alterations in circulating adipokines. However, a detailed understanding of CR-induced adipocyte secretome changes remains elusive. Therefore, we investigated the effect of CR on the secretion profile of mature human adipocytes by using proteomics technology with bioinformatic analysis. We demonstrated CR-mediated adipocyte triglyceride reduction, which resulted in a positive effect on adipokine secretion indicating an improved inflammatory phenotype and alleviation of obesity-associated metabolic dysfunction including insulin resistance and glucose intolerance. Furthermore, 6 novel adipocyte-secreted proteins were identified which were regulated by CR. Since resveratrol (RSV) mimics CR we compared results from this study with data from our previous RSV study on the adipocyte secretome. We observed that both treatment strategies lead to a less inflammatory phenotype and an altered adipokine profile indicating improvement of metabolic complications even though the CR and RSV adipocyte secretomes differed from each other.
2016-05-25 | PXD000301 | Pride
Project description:Obesity-induced inflammation metabolic dysfunction, but the mechanisms remain elusive. Here we showed that the innate immune factor IRF3 is a direct transcriptional regulator of glucose homeostasis through induction of endogenous FAHFA hydrolase Aig1 in adipocytes. Adipocyte-specific knockout IRF3 protects mice against high-fat diet-induced insulin resistance, whereas overexpression of IRF3 in adipocytes promotes insulin resistance on a high-fat diet. Furthermore, pharmacological inhibition of AIG1 reversed obesity-induced insulin resistance and restored glucose homeostasis in the setting of adipocyte IRF3 overexpression. We therefore, identify the adipocyte IRF3/AIG1 axis as a crucial link between obesity-induced inflammation and insulin resistance and suggest an approach for limiting the metabolic dysfunction accompanying obesity.
2024-02-09 | GSE213048 | GEO
Project description:Aims: Adipocytes are critical cornerstones of energy metabolism. While obesity-induced adipocyte dysfunction is associated with insulin resistance and systemic metabolic disturbances, adipogenesis, the formation of new adipocytes and healthy adipose tissue expansion are associated with metabolic benefits. Understanding the molecular mechanisms governing adipogenesis is of great clinical potential to efficiently restore metabolic health in obesity. Here we investigate the role of Heart and neural crest derivatives-expressed protein 2 (HAND2) in adipogenesis. Methods: Human white adipose tissue (WAT) were collected in a cross-sectional study of 318 individuals. In vitro, for mechanistic experiments we used primary adipocytes from human and mice as well as human multipotent adipose derived stem (hMADS) cells. Gene silencing was performed using siRNA or genetic inactivation in primary adipocytes from LoxP mouse models with Cre-encoding mRNA. Adipogenesis efficiency was measured by OilRedO staining, qPCR and microarray. A combinatorial RNASeq approach was used to identify gene clusters regulated by HAND2. In vivo, we created a conditional adipocyte Hand2 deletion mouse model using Cre under control of the Adipoq promoter (HAND2AdipoqCRE). Results: We found that HAND2 is an obesity-linked white adipocyte transcription factor regulated by glucocorticoids that was required but insufficient for adipocyte differentiation in vitro. In a large cohort of humans with obesity, WAT HAND2 expression was correlated to body-mass-index (BMI). The HAND2 gene was enriched in white adipocytes compared to brown, induced early in differentiation and responded to DEX, a typical glucocorticoid receptor (GR, encoded by NR3C1) agonist. Silencing of NR3C1 in hMADS or deletion of GR in a transgenic conditional mouse model results in diminished HAND2 expression, establishing that adipocyte HAND2 is regulated by GCs via GR in vitro and in vivo. Furthermore, we identified gene clusters indirectly regulated by the GR-HAND2 pathway. Interestingly, silencing of HAND2 impaired adipocyte differentiation in hMADS and primary mouse adipocytes. However, a conditional adipocyte Hand2 deletion mouse model using Cre under control of the Adipoq promoter did not mirror these effects on adipose tissue differentiation, indicating that Hand2 was required at stages prior to Adipoq expression. Conclusion: In summary, our study identifies HAND2 as a novel obesity-linked adipocyte transcription factor, highlighting new mechanisms of GR-dependent adipogenesis in human and mice.
2021-02-26 | GSE148699 | GEO
Project description:This study examines the transgenerational adipocyte (fat cell) epigenetic alterations in F3 generation obese and lean rats ancestrally exposed to DDT and atrazine. Adipocytes were isolated from the gonadal fat pad of F3 generation 1-year old rats ancestrally exposed to DDT, atrazine, or vehicle control in order to obtain adipocyte DNA for DNA methylation analysis. Observations indicate that there were differential DNA methylated regions (DMRs) in the adipocytes with the lean or obese phenotypes compared to control normal (non-obese or lean) populations. Interestingly, there were epigenetic changes that were distinct when comparing the lean and obese DMRs between the control and exposure lineage groups. DMR gene associations were identified which included common set of genes previously shown to associate with adipocyte pathology. The comparison of epigenetic alterations indicated that there were substantial overlaps between the different treatment lineage groups for both the lean and obese phenotypes. Novel correlated genes and gene pathways associated with DNA methylation were identified, and may aid in the discovery of potential therapeutic targets for metabolic diseases such as obesity.
2019-12-31 | GSE137536 | GEO
Project description:Toll-like receptors/Interleukin-1 receptor (IL-1R) signaling plays an important role in High-fat diet (HFD)-induced adipose tissue dysfunction contributing to obesity-associated metabolic syndromes. Here, we show an unconventional IL-1R-IRAKM (IL-1R-associated kinase M)-Slc25a1 signaling axis in adipocytes that reprograms lipogenesis to promote diet-induced obesity. Adipocyte-specific deficiency of IRAKM reduced HFD-induced body weight gain, increased whole body energy expenditure and improved insulin resistance, associated with decreased lipid accumulation and adipocyte cell sizes. IL-1β stimulation induced the translocation of IRAKM Myddosome to mitochondria to promote de novo lipogenesis in adipocytes. Mechanistically, IRAKM interacts with and phosphorylates mitochondrial citrate carrier Slc25a1 to promote IL-1β-induced mitochondrial citrate transport to cytosol and de novo lipogenesis. Moreover, IRAKM-Slc25a1 axis mediates IL-1β induced Pgc1a acetylation to regulate thermogenic gene expression in adipocytes. IRAKM kinase-inactivation also attenuated HFD-induced obesity. Taken together, our study suggests that the IL-1R-IRAKM-Slc25a1 signaling axis tightly links inflammation and adipocyte metabolism, indicating a novel therapeutic target for obesity.
2022-06-09 | PXD031934 | Pride
Project description:Extracellular vesicles are emerging key actors in adipocyte communication. Notably, small extracellular vesicles shed by adipocytes promote melanoma aggressiveness through fatty acid oxidation, with a heightened effect in obesity. However, the vesicular actors and cellular processes involved remain largely unknown. Here, we elucidate the mechanisms linking adipocyte extracellular vesicles to metabolic remodeling and cell migration. Using an adapted SILAC technique, we show that adipocyte vesicles stimulate melanoma fatty acid oxidation by providing both enzymes and substrates. In obesity, the heightened effect of extracellular vesicles depends on increased transport of fatty acids, not fatty acid oxidation related enzymes as shown by classical LC-MS/MS analysis. These fatty acids, stored within lipid droplets in cancer cells, drive fatty acid oxidation after release through lipophagy. This increase in mitochondrial activity redistributes mitochondria to membrane protrusions of migrating cells, which is necessary to increase cell migration in the presence of adipocyte vesicles. Our results provide key insights into the role of extracellular vesicles in the metabolic cooperation that takes place between adipocytes and tumors with particular relevance in obesity.
2020-01-09 | PXD014487 | Pride
Project description:Obesity is linked to the development of metabolic disorders. Expansion of white adipose tissue (WAT) from hypertrophy of pre-existing adipocytes and/or differentiation of precursors into new mature adipocytes contributes to obesity. We found that Nck2 expression is largely restricted to WAT, raising the hypothesis that it may play a unique function in that tissue. Using mice lacking Nck2, we found that Nck2 regulates adipocyte hypertrophy thus contributing to increased adiposity and progressive glucose intolerance, insulin resistance and hepatic steatosis. These findings were recapitulated in humans such that Nck2 expression in omental WAT was inversely correlated with the degree of obesity. Mechanistically, Nck2 deficiency promoted the induction of an adipocyte differentiation program and signaling by the PERK-eIF2α-ATF4 pathway in agreement with a role for the unfolded protein response in adipogenesis. These findings uncover Nck2 as a novel regulator of adipogenesis and that perturbation in its functionality contributes to adiposity-related metabolic disorders. Differential gene expression profile between epididymal white adipose tissue of Nck2-/- and Nck2+/+ mice by RNA sequencing (Illumina HiSEq 2000)
2016-07-01 | E-GEOD-63510 | biostudies-arrayexpress