Project description:Increased adiposity is a hallmark of obesity and overweight, which affect 2.2 billion people world-wide. Understanding the genetic and molecular mechanisms that underlie obesity-related phenotypes can help to improve treatment options and drug development. Here we perform promoter Capture Hi-C in human adipocytes to investigate interactions between gene promoters and distal elements as a transcription-regulating mechanism contributing to these phenotypes. We find that promoter-interacting elements in human adipocytes are enriched for adipose-related transcription factor motifs, such as PPARG and CEBPB, and contribute to heritability of cis-regulated gene expression. We further intersect these data with published genome-wide association studies for BMI and BMI-related metabolic traits to identify the genes that are under genetic cis regulation in human adipocytes via chromosomal interactions. This integrative genomics approach identifies four cis-eQTL-eGene relationships associated with BMI or obesity-related traits, including rs4776984 and MAP2K5, which we further confirm by EMSA, and highlights 38 additional candidate genes.
Project description:In the original version of this Article, Supplementary Table 10 contained incorrect primer sequences for the mobility shift assay for SNP rs4776984. These errors have now been fixed and the corrected version of the Supplementary Information PDF is available to download from the HTML version of the Article.
Project description:Chromatin accessibility and gene expression in relevant cell contexts can guide identification of regulatory elements and mechanisms at genome-wide association study (GWAS) loci. To identify regulatory elements that display differential activity across adipocyte differentiation, we performed ATAC-seq and RNA-seq in a cell model of preadipocytes and adipocytes at days 4 and 14 of differentiation. For comparison, we created a consensus map of ATAC-seq peaks in 11 subcutaneous adipose tissue samples. A set of 15,919 adipocyte-dependent peaks showed stronger enrichment (60.1%) of adipocyte nuclei enhancers than 51,855 adipose tissue peaks (44.6%) or 18,244 preadipocyte-dependent peaks (11.5%). We linked context-dependent peaks to genes based on adipocyte promoter capture Hi-C data, overlap with adipose eQTL variants, and differential gene expression. Of 16,167 context-dependent peaks that could be linked to a gene, 5,184 were linked by two or more strategies to 1,675 genes. Among GWAS loci for cardiometabolic traits, adipocyte peaks showed the strongest enrichment for waist-to-hip ratio, coronary artery disease, and HDL-cholesterol, while adipose tissue peaks also showed significant enrichment for LDL-cholesterol and triglyceride levels. We identified 666 peaks linked to 507 genes by two or more methods and overlapping a GWAS signal, suggesting a regulatory mechanism at these loci. At one GWAS locus for palmitoleic acid, rs603424 was located in an adipocyte-dependent peak linked to SCD and exhibited allelic differences in transcriptional activity in adipocytes (P=0.003) but not preadipocytes (P=0.09). These results demonstrate that context-dependent peaks and genes can guide discovery of regulatory variants at GWAS loci and aid identification of regulatory mechanisms.
Project description:Chromatin accessibility and gene expression in relevant cell contexts can guide identification of regulatory elements and mechanisms at genome-wide association study (GWAS) loci. To identify regulatory elements that display differential activity across adipocyte differentiation, we performed ATAC-seq and RNA-seq in a cell model of preadipocytes and adipocytes at days 4 and 14 of differentiation. For comparison, we created a consensus map of ATAC-seq peaks in 11 subcutaneous adipose tissue samples. A set of 15,919 adipocyte-dependent peaks showed stronger enrichment (60.1%) of adipocyte nuclei enhancers than 51,855 adipose tissue peaks (44.6%) or 18,244 preadipocyte-dependent peaks (11.5%). We linked context-dependent peaks to genes based on adipocyte promoter capture Hi-C data, overlap with adipose eQTL variants, and differential gene expression. Of 16,167 context-dependent peaks that could be linked to a gene, 5,184 were linked by two or more strategies to 1,675 genes. Among GWAS loci for cardiometabolic traits, adipocyte peaks showed the strongest enrichment for waist-to-hip ratio, coronary artery disease, and HDL-cholesterol, while adipose tissue peaks also showed significant enrichment for LDL-cholesterol and triglyceride levels. We identified 666 peaks linked to 507 genes by two or more methods and overlapping a GWAS signal, suggesting a regulatory mechanism at these loci. At one GWAS locus for palmitoleic acid, rs603424 was located in an adipocyte-dependent peak linked to SCD and exhibited allelic differences in transcriptional activity in adipocytes (P=0.003) but not preadipocytes (P=0.09). These results demonstrate that context-dependent peaks and genes can guide discovery of regulatory variants at GWAS loci and aid identification of regulatory mechanisms.
Project description:We perform promoter Capture Hi-C in human adipocytes to investigate interactions between gene promoters and distal elements as a transcription-regulating mechanism contributing to these phenotypes. We find that promoter-interacting elements in human adipocytes are enriched for adipose-related transcription factor motifs, such as PPARG and CEBPB, and contribute to heritability of cis-regulated gene expression. David Pan was funded through Grant Title: Biomedical Big Data Training Grant Grant ID: T32LM012424 Funding Source: National Institutes of Health-National Cancer Institute Marcus Alvarez was funded through Grant Title: NIH training grant in Genomic Analysis and Interpretation Grant ID: T32HG002536 Funding Source: National Institutes of Health
Project description:In obesity, misalignment of feeding time with the light/dark environment results in disruption of peripheral circadian clocks. Conversely, restricting feeding to the active period mitigates metabolic syndrome through mechanisms that remain unknown. Here we show that adipocyte thermogenesis is essential for the healthful metabolic response to time restricted feeding. Genetic enhancement of adipocyte thermogenesis through ablation of Zfp423 attenuates obesity caused by circadian mistimed high fat diet feeding through a mechanism involving creatine metabolism. Circadian control of adipocyte creatine metabolism underlies timing of diet-induced thermogenesis, and enhancement of adipocyte circadian rhythms through overexpression of the clock activator Bmal1 ameliorates metabolic complications during diet induced obesity. These findings establish creatine mediated diet-induced thermogenesis as a bioenergetic mechanism driving metabolic benefits during time-restricted feeding.
Project description:GWAS studies and our own work have identified RSPO3 as a gene modulating human body fat distribution. The GWAS signal at RSPO3 is coincident with an eQTL in mature adipocytes. To assess the effects of RSPO3 on abdominal and gluteal adipocyte biology, we undertook inducible RSPO3-knockdown in in vitro differentiated immortalized human abdominal and gluteal adipocyte cell lines (DFAT cells).