Project description:Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity [BAT]
Project description:Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity
Project description:Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity [BAT]
Project description:Brown Adipose YY1 Deficiency Activates Expression of Secreted Proteins Linked to Energy Expenditure and Prevents Diet-Induced Obesity [IWAT]
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.
Project description:Adipocytes are key players in maintaining energy homeostasis and are classified into two different categories: white and brown adipocyte. While white adipocytes store energy as triacylglycerols in lipid droplets, brown adipocytes combust excess chemical energy and release in the form of heat through uncoupled respiration. This characteristic phenomenon of brown fat attracts researchers and pharmacological industries to view brown fat as one of the potential therapeutic targets for obesity and associated metabolic disease. In the current study, we investigated the effect of a small molecule, sesaminol (SML) on brown fat activity and found that SML induces thermogenic program in primary white adipocytes as well as chow diet fed mice. In particular, SML treatment to mice elevated mitochondrial complex proteins and the rate oxygen consumption in brown and white fat. Administration of SML to high fat diet (HFD) challenged mice decreased weight gain, adiposity and cholesterol levels along with an increase of brown fat gene program in brown and white fat. Mechanistically, SML repressed the myogenic gene program in C2C12 myoblasts and increased all mitochondrial marker genes as appeared in brown adipose cells. Together, our results demonstrate that SML stimulates brown adipose function and protects mice against diet induced weight gain.
Project description:Brown adipose tissue (BAT) is a thermogenic organ that dissipates stored energy as heat to maintain body temperature in infants and small mammals. This process may also provide protection from development of diet-induced obesity. We found that the bioactive lipid mediator lysophosphatidic acid (LPA) markedly decreases differentiation of cultured primary brown adipocyte precursors, while potent selective inhibitors of the LPA-generating enzyme autotaxin (ATX) promote differentiation. Transgenic mice overexpressing ATX exhibited reduced expression of BAT-related genes in peripheral white adipose tissue and accumulated significantly more fat than wild-type controls when fed a high fat diet. Our results indicate that ATX and its product LPA are physiologically relevant negative regulators of brown fat adipogenesis and suggest that a decrease in peripheral brown adipose tissue results in increased susceptibility to diet-induced obesity in mice.
Project description:Adipose tissue is central to regulation of systemic energy homeostasis. Adaptive thermogenesis in brown and beige adipocytes, which relies on mitochondrial oxidative phosphorylation, dissipates energy to counteract obesity. On the other hand, chronic inflammation in adipose tissue is linked to insulin resistance, type 2 diabetes and obesity. Here we show that nuclear factor I-A (NFIA), a transcriptional regulator of brown and beige adipocytes, improves systemic glucose homeostasis via up-regulation of oxidative phosphorylation and reciprocal down-regulation of inflammation. Mice with transgenic expression of NFIA in adipocytes exhibited improved glucose tolerance, increased energy expenditure and limited weight gain on high fat diet. NFIA coordinately up-regulate genes involved in oxidative phosphorylation as well as a battery of brown-fat-specific genes through enhancer activation that involves facilitated genomic binding of PPARγ. In contrast, NFIA in adipocytes, but not in macrophages, down-regulate pro-inflammatory cytokine genes to ameliorate adipose tissue inflammation in vivo. NFIA binds to enhancer/promoter region of Ccl2 gene that encodes pro-inflammatory cytokine MCP-1, to down-regulate its transcription. NFIA expression and CCL2 expression was negatively correlated in human adipose tissue. These results indicate that NFIA in adipocytes reciprocally regulate mitochondrial and inflammatory gene program to improve systemic glucose homeostasis.
Project description:Adipose tissue is central to regulation of systemic energy homeostasis. Adaptive thermogenesis in brown and beige adipocytes, which relies on mitochondrial oxidative phosphorylation, dissipates energy to counteract obesity. On the other hand, chronic inflammation in adipose tissue is linked to insulin resistance, type 2 diabetes and obesity. Here we show that nuclear factor I-A (NFIA), a transcriptional regulator of brown and beige adipocytes, improves systemic glucose homeostasis via up-regulation of oxidative phosphorylation and reciprocal down-regulation of inflammation. Mice with transgenic expression of NFIA in adipocytes exhibited improved glucose tolerance, increased energy expenditure and limited weight gain on high fat diet. NFIA coordinately up-regulate genes involved in oxidative phosphorylation as well as a battery of brown-fat-specific genes through enhancer activation that involves facilitated genomic binding of PPARγ. In contrast, NFIA in adipocytes, but not in macrophages, down-regulate pro-inflammatory cytokine genes to ameliorate adipose tissue inflammation in vivo. NFIA binds to enhancer/promoter region of Ccl2 gene that encodes pro-inflammatory cytokine MCP-1, to down-regulate its transcription. NFIA expression and CCL2 expression was negatively correlated in human adipose tissue. These results indicate that NFIA in adipocytes reciprocally regulate mitochondrial and inflammatory gene program to improve systemic glucose homeostasis.
Project description:Adipose tissue is central to regulation of systemic energy homeostasis. Adaptive thermogenesis in brown and beige adipocytes, which relies on mitochondrial oxidative phosphorylation, dissipates energy to counteract obesity. On the other hand, chronic inflammation in adipose tissue is linked to insulin resistance, type 2 diabetes and obesity. Here we show that nuclear factor I-A (NFIA), a transcriptional regulator of brown and beige adipocytes, improves systemic glucose homeostasis via up-regulation of oxidative phosphorylation and reciprocal down-regulation of inflammation. Mice with transgenic expression of NFIA in adipocytes exhibited improved glucose tolerance, increased energy expenditure and limited weight gain on high fat diet. NFIA coordinately up-regulate genes involved in oxidative phosphorylation as well as a battery of brown-fat-specific genes through enhancer activation that involves facilitated genomic binding of PPARγ. In contrast, NFIA in adipocytes, but not in macrophages, down-regulate pro-inflammatory cytokine genes to ameliorate adipose tissue inflammation in vivo. NFIA binds to enhancer/promoter region of Ccl2 gene that encodes pro-inflammatory cytokine MCP-1, to down-regulate its transcription. NFIA expression and CCL2 expression was negatively correlated in human adipose tissue. These results indicate that NFIA in adipocytes reciprocally regulate mitochondrial and inflammatory gene program to improve systemic glucose homeostasis.