Project description:The adipose tissue plays an important role in controlling whole-body energy balance, and proper regulation of adipose tissue function is essential for metabolic health. In response to energy surplus, the adipose tissue needs to expand, which may lead to local areas of hypoxia within the tissue. This is thought to promote whole-body insulin resistance. Here we report that DICER, a key enzyme in the maturation of miRNAs and a potential marker of adipocyte health, is profoundly downregulated in mouse adipose tissue within the first week of high-fat diet (HFD) feeding, and this effect is sustained in response to long-term HFD feeding. The downregulation of DICER protein occurs in both mature adipocytes and in the stromal vascular cells. Mechanistically, we provide evidence that hypoxia and hypoxia-inducible factor 1-α (HIF1α) facilitate ubiquitination of DICER to target it for autophagy-mediated degradation, and we show that DICER and HIF1α interact in adipose tissue after HFD feeding, which may signal for DICER degradation. Finally, despite reductions in DICER protein, we were not able to detect any differences in global miRNA levels in subcutaneous adipose tissue of mice after one or three weeks of HFD-feeding. In conclusion, the nutritional challenge of HFD feeding in mice leads to a large reduction in adipose tissue DICER protein, which is induced by hypoxia during tissue expansion and mediated through an interaction with HIF1α.
Project description:The goal of this study is to identify the cistrome of the transcriptional repressor Rev-erb alpha in epididymal white adipose tissue. Performing Rev-erb alpha ChIP-seq on epididymal white adipose tissue from wildtype mice at 5PM when Rev-erb alpha protein level peaks in wild type (WT) mice, we were able to globally determine the genomic regions undergoing Rev-erb alpha-dependent de-repression. Examination of Rev-erb alpha binding in epididymal white adipose tissue.
Project description:<p>The Finland-United States Investigation of NIDDM Genetics (FUSION) study is a long-term effort to identify genetic variants that predispose to type 2 diabetes (T2D) or that impact the variability of T2D-related quantitative traits (QTs). Skeletal muscle and adipose are major insulin target tissues and play key roles in insulin resistance. We hypothesize that a subset of T2D and related QT variants alter gene expression in skeletal muscle and adipose tissue. For this FUSION Tissue Biopsy Study, we have obtained and are analyzing RNA-Seq, microRNA (miRNA)-Seq, and DNA methylation (methyl)-Seq data on biopsy samples from 331 individuals from across the range of glucose tolerance: 124 normal glucose tolerance (NGT), 77 impaired glucose tolerance (IGT), 44 impaired fasting glucose (IFG), and 86 newly-diagnosed T2Ds. Participants completed two study visits, two weeks apart. First visits comprised most of the clinical phenotyping, including four-point OGTT (fasting, and 30, 60, and 120 minute post-load); BMI, WHR; lipids; blood pressure; and many other variables. Participants also completed FUSION health history, medication, and lifestyle questionnaires. At second visit, we obtained ~250mg <i>vastus lateralis</i> skeletal muscle, ~750mg abdominal subcutaneous adipose, and a ~5x15mm section of abdominal skin. Visits were completed in March 2013. RNA isolation is ongoing in the Collins laboratory at the NIH, RNA and miRNA sequencing at the NIH Intramural Sequencing Center (NISC), and genotyping at the Center for Inherited Disease Research (CIDR). Individual-level data is available here for the 306 individuals who consented to data deposit.</p> <p>To focus on evaluation of gene expression and its regulation in skeletal muscle, we analyzed mRNA extracted from <i>vastus lateralis</i> skeletal muscle obtained from 271 of the 331 individual subjects from Finland, along with genome-wide genotypes. Individual-level data is available here for the 250 subjects who reconsented to the use of their data. Release phs001048.v2.p1 adds muscle data for an additional 42 subjects and data from adipose tissue for 276 subjects. Total RNA was isolated using Trizol extraction in the Collins laboratory at the NIH. The mRNA was poly-A selected, 24-plex libraries were generated using the Illumina TruSeq directional mRNA-seq library protocol and RNA sequencing was performed on HiSeq2000 sequencers using 101bp paired-end reads at NISC. miRNA libraries were prepared from total RNA from 296 muscle and 270 adipose samples, pooled and sequenced 50bp single-end reads on Illumina HiSeq2500. Data for 272 muscle and 251 adipose samples are available here for individuals with consent for data deposit. DNA was extracted from blood in the Collins laboratory, and genotyping on the Illumina Omni2.5M array was performed at CIDR. Genotypes were imputed using the HRC 2016 reference panel. In order to assess regions of open chromatin in skeletal muscle, we obtained muscle tissue from a commercial provider to perform ATAC-seq; these samples were sequenced at the University of Michigan DNA Sequencing Core.</p> <p>Greater than 90% of the approximately 80 loci associated with T2D and the 100s of loci associated with T2D-related traits (glucose and insulin, anthropometrics, lipids) through genome-wide association studies occur in non-coding regions, suggesting a strong regulatory component to disease susceptibility. Regulatory element activity is often tissue-specific, which further complicates discovery of the causal/functional variation. Therefore, there is a critical need to understand the full spectrum of genetic variation and regulatory element usage in T2D-relevant tissues. To that end, this study contains whole genome sequence and whole genome bisulfite sequence, and/or Illumina MethylationEPIC Array data, of two tissues relevant to T2D: skeletal muscle and adipose tissue from individuals with glucose tolerance categories ranging from normal to T2D, providing a comprehensive survey of both individual genetic variation as well as DNA methylation across different tissues from multiple individuals.</p>
Project description:Scope: Adipose tissue is regarded as a true endocrine organ. Recent studies showed that adipose tissue derived exosomes could serve as carrier of circulating miRNAs to regulate distant targets. However, the characteristics of exosomal proteins released from adipose tissue have not been investigated yet. Methods and Results: In this study, we conducted a complementary protein profiling on exosome-like vesicles derived from adipose tissue (ELV-AT) with Label-free Quantitative Proteomic Analysis. A total of 3229 ELV-AT proteins were identified, among which only 266 proteins have been annotated as adipokines. 3 undefined adipokine candidates (NPM3, STEAP3, and DAD1) were selected for further validation. These 3 proteins were expressed in both white and brown adipose tissue, upregulated during adipogenic differentiation of both 3T3-L1 cells and adipose derived stem cells (ADSCs). Expressions of NPM3, DAD1 in ELV-AT were significantly decreased in obese subjects compared with lean controls while obesity could not alter the expression of STEAP3. Conclusions: Our profiling study of the ELV-AT proteins expands the list of adipokines and highlights the pivotal role of exosomal adipokines in the regulation of multiple biological processes within adipose tissue
Project description:MicroRNAs (miRNAs) are small non-coding RNAs found to regulate several biological processes including adipogenesis. Understanding adipose tissue regulation is critical for beef cattle as fat is an important determinant of beef quality and nutrient value . This study analyzed the association between genomic context characteristics of miRNAs with their expression and function in bovine adipose tissue. Twenty-four subcutaneous adipose tissue biopsies were obtained from eight British-continental crossbred steers at 3 different time points . Total RNA was extracted and miRNAs were profiled using a miRNA microarray with expression further validated by qRT-PCR. A total of 224 miRNAs were detected of which 155 were expressed in all steers (n=8), and defined as the core miRNAs of bovine subcutaneous adipose tissue. Core adipose miRNAs varied in terms of genomic location (59.5% intergenic, 38.7% intronic, 1.2% exonic, and 0.6% mirtron), organization (55.5% non-clustered and 44.5% clustered), and conservation (49% highly conserved, 14% conserved and 37% poorly conserved). Clustered miRNAs and highly conserved miRNAs were more highly expressed (p<0.05) and had more predicted targets than non-clustered or less conserved miRNAs (p<0.001). A total of 34 miRNAs were coordinately expressed, being part of six identified relevant networks. Two intronic miRNAs (miR-33a and miR-1281) were shown to have coordinated expression with their host genes which are involved in lipid metabolism, suggesting these miRNAs may also play a role in regulation of lipid metabolism/adipogenesis of bovine adipose tissue. Furthermore, a total of 17 bovine specific miRNAs were predicted to be involved in the regulation of energy balance in adipose tissue. These findings improve our understanding on the behavior of miRNAs in the regulation of bovine adipogenesis and fat metabolism as it reveals that miRNA expression patterns and functions are associated with miRNA genomic organization and conservation in bovine adipose tissue.
Project description:Prolonged fasting-induced changes in rat white adipose tissue (epidydimal) transcriptome White adipose tissue is a central place to energy storage and a major endocrine organ. However, adipose molecular mechanisms have been poorly studied during prolonged fasting. To fill this gap, the aim of this study was to decipher transcriptomic regulations in rat adipose tissue during phase 2 (lipid mobilization) and phase 3 (protein catabolism) of prolonged fasting compared to the fed state. We describe a regulatory transcriptional program in epididymal adipose tissue in line with lipogenesis repression during both phases, and that would favor lipolysis during phase 2 and repress it during phase 3. Such regulations notably involve selective (i.e. phase-dependent) changes in gene expression levels of lipases, lipid droplet-associated factors, and the proteins involved in cAMP-dependent and cAMP-independent regulation of lipolysis. The mRNA levels of adipose-secreted factors were globally consistent with the repression of insulin signalling during prolonged fasting. Regulations of leptin and adiponectin levels could be related to their respective role in triggering refeeding during late fasting and controlling lipid metabolism. Specific responses reflecting adipose tissue inflammation, increased fibrinolysis and a possible protein catabolism-related energy saving mechanism were also recorded during phase 3. These data thus provide a comprehensive molecular basis of adipose tissue responses according to the fasting stage.
Project description:Breaking up prolonged periods of time spent sitting has a range of beneficial impacts on cardiometabolic risk biomarkers. The molecular mechanisms include regulation of skeletal muscle gene and protein expression controlling metabolic, inflammatory and cell development pathways. An active communication network exists between adipose and muscle tissue, but the effect of active breaks in prolonged sitting on adipose tissue have yet to be investigated. This study characterised the acute transcriptional events induced in adipose tissue by regular active breaks during prolonged sitting. In a subset of 8 overweight/obese adults participating in an acute randomised three-intervention crossover trial, subcutaneous adipose tissue biopsies were obtained after each condition. The three experimental conditions were conducted in the postprandial state and included: i) prolonged uninterrupted sitting; or prolonged sitting interrupted with 2-minute bouts of ii) light- or iii) moderate-intensity treadmill walking every 20 minutes. Microarrays identified 36 differentially expressed genes between the three conditions (fold change≥0.5 in either direction; p<0.05). Pathway analysis indicated that breaking up of prolonged sitting led to differential regulation of adipose tissue metabolic networks and inflammatory pathways, increased insulin signalling, increased adipocyte turnover, and facilitated cross-talk between adipose tissue and other organs. This study provides insight into the adipose tissue regulatory systems and transcriptional processes that contribute to the physiological benefits of interrupting prolonged sitting.
Project description:Adipose Energy Homeostasis is the important guarantee to maintain the body's energy balance. Recently, it is reported that, in the adipose cell, Kisspeptins play important role in cell proliferation, differentiation, lipid metabolism and some adipocytokine secretion, so Kisspeptins maybe the novel targets of adipose energy homeostasis regulation. Adipose tissue is the core organs that regulates adipose energy homeostasis. Our early studies observed that there is organizational difference that exercise regulated adipose energy homeostasis, and the response of the Kisspeptins to exercise is closely related to the energy state of the body, so we speculated that Kisspeptins play some important role in the exercise regulated adipose energy homeostasis. Based on the cell experiments to clarify the role of Kisspeptins in regulating adipose energy homeostasis, the role of Kisspeptins in the regulation of adipose energy homeostasis were determined in the adipose tissue of conditioned Kiss1 gene knockout mice of CRISPR/Cas9, then we use the single cell transcriptome sequencing, untargeted proteome and targeted metabolome techniques to further explore and elucidate the possible pathways and mechanisms of Kisspeptins mediated adipose energy homeostasis regulated by exercise.