Project description:Objective: Brown adipose tissue (BAT) is important for thermoregulation in many mammals. Uncoupling protein 1 (UCP1) is the critical regulator of thermogenesis in BAT. Here we aimed to investigate the deacetylation control of BAT and to investigate a possible functional connection between UCP1 and sirtuin 3 (SIRT3), the master mitochondrial deacetylase. Methods: We carried out physiological, molecular and proteomic analyses of BAT from wild-type and Sirt3KO mice when BAT is activated. Mice were either cold exposed for 2 days or were injected with the β3-adrenergic agonist, CL316,243 (1mg/kg; i.p.). Mutagenesis studies were conducted in a cellular model to assess the impact of acetyaltion lysine sites on UCP1 function. Cardiac punctures were collected for Proteomic analysis of Acylcarnitines. Isolated mitochondria were used for functional analysis of OXPHOS. Results: Our findings showed that SIRT3 absence in mice resulted in impaired BAT lipid use, whole body thermoregulation, and respiration in BAT mitochondria, without affecting UCP1 expression. Acetylome profiling of BAT mitochondria revealed that SIRT3 regulates acetylation status of many BAT mitochondrial proteins including UCP1 and crucial upstream proteins. Mutagenesis work in cells suggested that UCP1 activity was independent of direct SIRT3-regulated lysine acetylation. However, SIRT3 impacted BAT mitochondrial activities of acylcarnitine metabolism and specific electron transport chain complexes, CI and CII.
Project description:The activation of brown/beige adipose tissue (BAT) metabolism and the induction of uncoupling protein-1 (UCP1) expression are essential for BAT-based strategies to improve metabolic homeostasis. Adrenergic signaling is viewed as a key regulator of thermogenesis and UCP1-expression in BAT, while also operating as a potent contractile stimulator in muscle. The muscle-like gene expression patterns of UCP1+ adipocytes have previously been utilized as tissue specific markers, but have not been attributed with any functional role. Here, we demonstrate that BAT utilizes actomyosin machinery to generate tensional responses following adrenergic stimulation, similar to muscle tissues. We show that activation of actomyosin mechanics are critical for the acute induction of oxidative metabolism and uncoupled respiration in UCP1+ adipocytes. Additionally, actomyosin-mediated elasticity regulates mechanosensitive transcriptional co-activators, YAP/TAZ, that facilitate the thermogenic capacity of adipocytes. These unappreciated signaling and mechanical mechanisms may inform future strategies to promote the expansion and activation of brown/beige adipocytes.
2018-03-01 | GSE109829 | GEO
Project description:Comparative analyses of eye transcriptomes of neotropical bats
Project description:Brown adipose tissue (BAT) is a thermogenic organ that protects animals against hypothermia and obesity. BAT derives from the multipotent paraxial mesoderm; however, the identity of embryonic brown fat progenitor cells and regulators of adipogenic commitment are unclear. Here, we performed single cell gene expression analyses of mesenchymal cells during mouse embryogenesis with a focus on BAT development.
Project description:Brown adipose tissue (BAT) is a thermogenic organ that protects animals against hypothermia and obesity. BAT derives from the multipotent paraxial mesoderm; however, the identity of embryonic brown fat progenitor cells and regulators of adipogenic commitment are unclear. Here, we performed single cell gene expression analyses of mesenchymal cells during mouse embryogenesis with a focus on BAT development.
Project description:Dysregulation of ERα has been linked with increased metabolic and cardiovascular disease risk. Uncovering the impact of ERα deficiency in specific tissues has implications for understanding the role of ERα in normal physiology and disease, the increased disease risk in postmenopausal women, and the design of tissue-specific ERα-based therapies for a range of pathologies including cardiac disease and cancer. Cardiac myocyte-specific ER knockout mice (ERαHKO) were generated to assess the role of ERα in the heart. Female ERαHKO mice displayed a modest cardiac phenotype, but unexpectedly, the most striking phenotype was obesity in female ERαHKO but not male ERαHKO mice. In female ERαHKO mice we identified cardiac dysfunction, mild glucose and insulin intolerance, and reduced ERα gene expression in skeletal muscle and white adipose tissue (WAT). Gene expression, protein, lipidomic and metabolomic analyses showed evidence of contractile and/or metabolic dysregulation in heart, skeletal muscle and WAT. We also show that extracellular vesicles (EVs) collected from the perfusate of isolated hearts from female ERαHKO mice have a distinct proteome, and these EVs have the capacity to reprogram the proteome of a skeletal muscle cell including proteins linked with ERα, fatty acid regulation, lipid metabolism and mitochondrial function. This study uncovers a cardiac-initiated and sex-specific cardiometabolic phenotype that is regulated by ERα.
Project description:Dysregulation of ERα has been linked with increased metabolic and cardiovascular disease risk. Uncovering the impact of ERα deficiency in specific tissues has implications for understanding the role of ERα in normal physiology and disease, the increased disease risk in postmenopausal women, and the design of tissue-specific ERα-based therapies for a range of pathologies including cardiac disease and cancer. Cardiac myocyte-specific ER knockout mice (ERαHKO) were generated to assess the role of ERα in the heart. Female ERαHKO mice displayed a modest cardiac phenotype, but unexpectedly, the most striking phenotype was obesity in female ERαHKO but not male ERHKO mice. In female ERαHKO mice we identified cardiac dysfunction, mild glucose and insulin intolerance, and reduced ERα gene expression in skeletal muscle and white adipose tissue (WAT). Gene expression, protein, lipidomic and metabolomic analyses showed evidence of contractile and/or metabolic dysregulation in heart, skeletal muscle and WAT. We also show that extracellular vesicles (EVs) collected from the perfusate of isolated hearts from female ERαHKO mice have a distinct proteome, and these EVs have the capacity to reprogram the proteome of a skeletal muscle cell including proteins linked with ERα, fatty acid regulation, lipid metabolism and mitochondrial function. This study uncovers a cardiac-initiated and sex-specific cardiometabolic phenotype that is regulated by ERα.
Project description:Compare miRNA expression profiles in epididymal white adipose tissue (WAT), interscapular brown adipose tissue (BAT) and skeletal muscle from wild-type C57BL/6J mice
Project description:Glucocorticoids (GCs) are widely applied anti-inflammatory drugs that are associated with adverse metabolic effects including insulin resistance and weight gain. Previous research indicated that GCs may negatively impact brown adipose tissue (BAT) in rodents and humans. Here, we demonstrate that treatment of human volunteers with high doses of GCs increases resting energy expenditure (REE) but does not reduce BAT activity. In line with the physiological results, gene expression in human BAT was not significantly altered by GCs in vivo. However, the RNA-sequencing of skeletal muscle revealed that GCs increase the expression of enzymes involved in calcium cycling as well as the respiratory chain. Collectively, these data suggest that the raise of EE after GCs exposure is mediated by skeletal muscle rather than a change in BAT activity.