Project description:Signaling pathways that promote adipose tissue thermogenesis are well characterized, but the physiologic limiters of energy expenditure are largely unknown. Here we show that ablation of the anti-inflammatory cytokine IL-10 improves insulin sensitivity, protects against diet-induced obesity, and elicits the browning of white adipose tissue. Mechanistic studies define bone marrow cells as the source of the IL-10 signal and mature adipocytes as the target cell type mediating these effects. IL-10 receptor alpha is highly enriched in mature adipocytes and is induced in response to cold, obesity and aging. ATAC-seq and RNA-seq reveal that IL-10 represses the transcription of thermogenic genes in adipocytes by altering chromatin accessibility and inhibiting ATF and PGC-1alpha recruitment to key enhancer regions. These findings identify the IL-10 axis as a critical and potentially targetable regulator of thermogenesis, and expand our understanding of the links between inflammatory signaling and adipose tissue function in the setting of obesity.
Project description:Signaling pathways that promote adipose tissue thermogenesis are well characterized, but the physiologic limiters of energy expenditure are largely unknown. Here we show that ablation of the anti-inflammatory cytokine IL-10 improves insulin sensitivity, protects against diet-induced obesity, and elicits the browning of white adipose tissue. Mechanistic studies define bone marrow cells as the source of the IL-10 signal and mature adipocytes as the target cell type mediating these effects. IL-10 receptor alpha is highly enriched in mature adipocytes and is induced in response to cold, obesity and aging. ATAC-seq and RNA-seq reveal that IL-10 represses the transcription of thermogenic genes in adipocytes by altering chromatin accessibility and inhibiting ATF and PGC-1alpha recruitment to key enhancer regions. These findings identify the IL-10 axis as a critical and potentially targetable regulator of thermogenesis, and expand our understanding of the links between inflammatory signaling and adipose tissue function in the setting of obesity.
Project description:Signaling pathways that promote adipose tissue thermogenesis are well characterized, but the physiologic limiters of energy expenditure are largely unknown. Here we show that ablation of the anti-inflammatory cytokine IL-10 improves insulin sensitivity, protects against diet-induced obesity, and elicits the browning of white adipose tissue. Mechanistic studies define bone marrow cells as the source of the IL-10 signal and mature adipocytes as the target cell type mediating these effects. IL-10 receptor alpha is highly enriched in mature adipocytes and is induced in response to cold, obesity and aging. ATAC-seq and RNA-seq reveal that IL-10 represses the transcription of thermogenic genes in adipocytes by altering chromatin accessibility and inhibiting ATF and PGC-1alpha recruitment to key enhancer regions. These findings identify the IL-10 axis as a critical and potentially targetable regulator of thermogenesis, and expand our understanding of the links between inflammatory signaling and adipose tissue function in the setting of obesity.
Project description:Signaling pathways that promote adipose tissue thermogenesis are well characterized, but the limiters of energy expenditure are largely unknown. Here, we show that ablation of the anti-inflammatory cytokine IL-10 improves insulin sensitivity, protects against diet-induced obesity, and elicits the browning of white adipose tissue. Mechanistic studies define bone marrow cells as the source of the IL-10 signal and adipocytes as the target cell type mediating these effects. IL-10 receptor alpha is highly enriched in mature adipocytes and is induced in response to differentiation, obesity, and aging. Assay for transposase-accessible chromatin sequencing (ATAC-seq), ChIP-seq, and RNA-seq reveal that IL-10 represses the transcription of thermogenic genes in adipocytes by altering chromatin accessibility and inhibiting ATF and C/EBPβ recruitment to key enhancer regions. These findings expand our understanding of the relationship between inflammatory signaling pathways and adipose tissue function and provide insight into the physiological control of thermogenesis that could inform future therapy.
Project description:Ten-eleven translocation (TET) proteins oxidize 5-methylcytosine in DNA to 5- hydroxymethylcytosine and further oxidized derivatives. Here we show that TET proteins are key epigenetic suppressors of adipocyte thermogenesis and energy expenditure in both white and brown adipose tissues in vivo. Tet expression in adipocytes decreases upon cold or adrenergic stimulation but increases following high-fat diet (HFD) consumption. Mice with triple deletion of all three Tet genes in adipocytes have higher energy expenditure due to enhanced fat browning and thermogenesis. They also show significantly enhanced lipolysis because of elevated expression of Adrb3 and key lipases including Atgl and Hsl. Consequently, the knockout mice display improved cold tolerance and are substantially resistant to obesity, inflammation, and associated metabolic complications including insulin resistance. Mechanistically, TET deficiency substantially prevents the HFD-induced transcriptional alterations in adipose tissues. TET proteins recruit histone deacetylases (HDACs) to the key thermogenic gene loci including Adrb3, Ppargc1a, and Ucp1, leading to transcriptional repression through histone deacetylation. Thus, the TET-HDAC axis may be therapeutically targeted to treat obesity and related metabolic diseases.