Regulation of cold-induced thermogenesis by the stress granule protein FAM195A
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE164964 | GEO | 2021/06/05
REPOSITORIES: GEO
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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.
2019-04-18 | PXD013056 | Pride
Project description:Various physiological stimuli, such as cold environment, diet, and hormones, trigger brown adipose tissue (BAT) to produce heat through sympathetic nervous system (SNS)- and -adrenergic receptors (ARs). The AR stimulation increases intracellular cAMP levels through heterotrimeric G proteins and adenylate cyclases, but the processes by which cAMP modulates brown adipocyte function are not fully understood. Here we described that specific ablation of cAMP production in brown adipocytes led to reduced lipolysis, mitochondrial biogenesis, uncoupling protein 1 (Ucp1) expression, and consequently defective adaptive thermogenesis. Elevated cAMP signaling by sympathetic activation inhibited Salt-inducible kinase 2 (Sik2) through protein kinase A (PKA)-mediated phosphorylation in brown adipose tissue. Inhibition of SIKs enhanced Ucp1 expression in differentiated brown adipocytes and Sik2 knockout mice exhibited enhanced adaptive thermogenesis at thermoneutrality in an Ucp1-dependent manner. Taken together, our data indicate that suppressing Sik2 by PKA-mediated phosphorylation is a requisite for SNS-induced Ucp1 expression and adaptive thermogenesis in BAT, and targeting Sik2 may present a novel therapeutic strategy to ramp up BAT thermogenic activity in humans.
2018-07-12 | PXD009262 | Pride
Project description:Brown adipose tissue (BAT) is a thermogenic organ that requires Uncoupling Protein 1 (UCP1) to dissipate chemical energy as heat, to defend core body temperature against hypothermia, and counteract obesity and metabolic diseases1. However, the transcriptional mechanism ensuring BAT thermogenic capacity for survival prior to environmental cold is unknown. Here we show histone deacetylase 3 (HDAC3) is a required transcriptional regulator of BAT enhancers to ensure thermogenic aptitude and survival. Mice with genetic ablation of HDAC3 become severely hypothermic and fail to survive acute cold exposure. UCP1 is nearly absent in BAT lacking HDAC3 and there is marked down-regulation of mitochondrial oxidative phosphorylation (OXPHOS) genes. Remarkably, although HDAC3 canonically functions as a transcriptional corepressor2, HDAC3 functions as a coactivator of the estrogen-related receptor _ (ERR_) in BAT, and loss of HDAC3 leads to robust global down-regulation of ERR±-driven enhancers. HDAC3 coactivation of ERR_ is mediated through deacetylation of PGC-1_ and is required for basal transcription of Ucp1, OXPHOS, and Pgc-1_. Thus, HDAC3 uniquely primes Ucp1 and thermogenic gene transcription to ensure immediate BAT-driven thermogenesis upon acute exposure to dangerously cold temperatures.
2017-06-14 | GSE83927 | GEO
Project description:Brown adipose tissue (BAT) is a thermogenic organ that requires Uncoupling Protein 1 (UCP1) to dissipate chemical energy as heat, to defend core body temperature against hypothermia, and counteract obesity and metabolic diseases1. However, the transcriptional mechanism ensuring BAT thermogenic capacity for survival prior to environmental cold is unknown. Here we show histone deacetylase 3 (HDAC3) is a required transcriptional regulator of BAT enhancers to ensure thermogenic aptitude and survival. Mice with genetic ablation of HDAC3 become severely hypothermic and fail to survive acute cold exposure. UCP1 is nearly absent in BAT lacking HDAC3 and there is marked down-regulation of mitochondrial oxidative phosphorylation (OXPHOS) genes. Remarkably, although HDAC3 canonically functions as a transcriptional corepressor2, HDAC3 functions as a coactivator of the estrogen-related receptor _ (ERR_) in BAT, and loss of HDAC3 leads to robust global down-regulation of ERR±-driven enhancers. HDAC3 coactivation of ERR_ is mediated through deacetylation of PGC-1_ and is required for basal transcription of Ucp1, OXPHOS, and Pgc-1_. Thus, HDAC3 uniquely primes Ucp1 and thermogenic gene transcription to ensure immediate BAT-driven thermogenesis upon acute exposure to dangerously cold temperatures.
2017-06-14 | GSE83926 | GEO
Project description:Non-shivering thermogenesis in adipocytes is mediated by brown adipose tissue, purportedly through the sole action of uncoupling protein 1 (UCP1). The physiological relevance of UCP1-dependent thermogenesis has primarily been inferred from the attenuation of thermogenic output of mice genetically lacking Ucp1 from birth (germline Ucp1-/-). However, germline Ucp1-/- mice harbor secondary changes within brown adipose tissue beyond UCP1, such as reduced electron transport chain abundance. We show here that these secondary changes also encompass reduced expression of genes regulating fuel liberation, changes that would attenuate the capacity of any thermogenic pathway. Therefore, the quantitative contribution of UCP1-dependent and -independent thermogenesis is not fully understood. To mitigate the potentially confounding ancillary changes to brown adipose tissue of germline Ucp1-/- mice, we constructed mice with inducible adipocyte-selective disruption of Ucp1. We find that, while germline Ucp1-/- mice succumb to cold-induced hypothermia with complete penetrance, most mice with inducible deletion of Ucp1 maintain homeothermy in the cold. However, inducible adipocyte-selective co-deletion of Ucp1 and creatine kinase B (Ckb, an effector of UCP1-independent thermogenesis) exacerbates cold-intolerance, indicative of a negative genetic interaction and thus a parallel thermogenic function. We find no evidence for impairments in insulation or non-shivering thermogenesis in skeletal muscle that would drive this phenotype. Furthermore, following UCP1 deletion or UCP1/CKB co-deletion from mature adipocytes, moderate cold exposure triggers the regeneration of mature adipocytes that coordinately restore UCP1 and CKB to brown adipose tissue, providing further evidence of their parallel thermogenic relationship. Our findings suggest that thermogenic adipocytes utilize non-paralogous protein redundancy – through UCP1 and CKB – to promote cold-induced energy dissipation.
2024-01-10 | PXD047841 | Pride
Project description:Brown adipose tissue (BAT) is best known for thermogenesis. Whereas numerous studies in rodents found tight associations between the metabolic benefits of BAT and enhanced whole-body energy expenditure, emerging evidence in humans suggests that BAT is protective against Type 2 diabetes independent of body-weight. The underlying mechanism for this dissociation remained unclear. Here, we report that impaired mitochondrial flux of branched-chain amino acids (BCAA) in BAT, by deleting mitochondrial BCAA carrier (MBC, encoded by Slc25a44), was sufficient to cause systemic insulin resistance without affecting whole-body energy expenditure or body-weight. We found that brown adipocytes catabolized BCAAs in the mitochondria as essential nitrogen donors for the biosynthesis of glutamate, N-acetylated amino acids, and one of the products, glutathione. BAT-selective impairment in mitochondrial BCAA flux led to elevated oxidative stress and insulin resistance in the liver, accompanied by reduced levels of BCAA-nitrogen derived metabolites in the circulation. In turn, supplementation of glutathione restored insulin sensitivity of BAT-specific MBC knockout mice. Notably, a high-fat diet rapidly impaired BCAA catabolism and the synthesis of BCAA-nitrogen derived metabolites in the BAT, while cold-induced BAT activity is coupled with an active synthesis of these metabolites. Together, the present work uncovers a mechanism through which brown fat controls metabolic health independent of thermogenesis via BCAA-derived nitrogen carriers acting on the liver.
2024-02-15 | PXD044020 | Pride
Project description:Brown adipose tissue (BAT) is best known for thermogenesis. Whereas numerous studies in rodents found tight associations between the metabolic benefits of BAT and enhanced whole-body energy expenditure, emerging evidence in humans suggests that BAT is protective against Type 2 diabetes independent of body-weight. The underlying mechanism for this dissociation remained unclear. Here, we report that impaired mitochondrial flux of branched-chain amino acids (BCAA) in BAT, by deleting mitochondrial BCAA carrier (MBC, encoded by Slc25a44), was sufficient to cause systemic insulin resistance without affecting whole-body energy expenditure or body-weight. We found that brown adipocytes catabolized BCAAs in the mitochondria as essential nitrogen donors for the biosynthesis of glutamate, N-acetylated amino acids, and one of the products, glutathione. BAT-selective impairment in mitochondrial BCAA flux led to elevated oxidative stress and insulin resistance in the liver, accompanied by reduced levels of BCAA-nitrogen derived metabolites in the circulation. In turn, supplementation of glutathione restored insulin sensitivity of BAT-specific MBC knockout mice. Notably, a high-fat diet rapidly impaired BCAA catabolism and the synthesis of BCAA-nitrogen derived metabolites in the BAT, while cold-induced BAT activity is coupled with an active synthesis of these metabolites. Together, the present work uncovers a mechanism through which brown fat controls metabolic health independent of thermogenesis via BCAA-derived nitrogen carriers acting on the liver.
2024-02-15 | PXD043992 | Pride
Project description:Obesity results from a caloric imbalance between energy intake, absorption and expenditure. In both rodents and humans, diet-induced thermogenesis contributes to energy expenditure and involves the activation of brown adipose tissue (BAT). We hypothesized that environmental toxicants commonly used as food additives or pesticides might reduce BAT thermogenesis through suppression of uncoupling protein 1 (UCP1) and this may contribute to the development of obesity. Using a step-wise screening approach, we discovered that the organophosphate insecticide chlorpyrifos suppresses UCP1 and mitochondrial respiration in BAT at concentrations as low as 1 pM. In mice housed at thermoneutrality and fed a high-fat diet, chlorpyrifos impaired BAT mitochondrial function and diet-induced thermogenesis, promoting greater obesity, non-alcoholic fatty liver disease (NAFLD) and insulin resistance. This was associated with reductions in cAMP; activation of p38MAPK and AMPK; protein kinases critical for maintaining UCP1 and mitophagy, respectively in BAT. These data indicate that the commonly used pesticide chlorpyrifos, suppresses diet-induced thermogenesis and the activation of BAT, suggesting its use may contribute to the obesity epidemic.
2021-07-19 | GSE178366 | GEO
Project description:Non-shivering thermogenesis in the brown adipose tissue (BAT) of rodents requires macronutrients to fuel the generation of heat during hypothermic conditions. Therefore, it is critical to identify signaling pathways which aid in nutrient delivery within this thermogenic tissue.To understand the contribution of the integrated stress response (ISR) in directing adaptive thermogenesis, we examined the role of the kinase activity of general control nonderepressible 2 (GCN2) within the BAT during acute cold exposure. We hypothesized that under hypothermic conditions, GCN2 maintains thermogenesis via ISR gene targets such as fibroblast growth factor 21 (FGF21), that triggers thermogenic uncoupling in BAT. In alignment with our hypothesis, both female and male mice either lacking GCN2 or administered a small molecule inhibitor of GCN2 were profoundly intolerant to acute cold stress. However, while GCN2 deletion in male mice impeded liver-derived FGF21 expression, it did not affect FGF21 levels in females, suggesting an alternative role for GCN2 in the maintenance of thermogenesis. Within the BAT, acute cold exposure increased ISR target genes and thermogenic genes regardless of GCN2 status and sex. RNA sequencing in BAT during cold exposure revealed a gene signature that identified actomyosin mechanics and transmembrane transport as the top two processes requiring GCN2. The top gene signature included cytoskeletal and class II myosin heavy chain genes critical for maximal thermogenesis during cold stress. The second gene signature included amino acid transporters which corresponded with higher circulating amino acids. In conclusion, we identify a novel role for GCN2 activation during acute cold exposure to facilitate mechanosensitive cell signaling and use of amino acids for adaptive thermogenesis.
2023-11-21 | GSE234972 | GEO
Project description:Brown adipose tissue (BAT) plays an essential role in metabolic homeostasis by dissipating energy via thermogenesis through uncoupling protein 1 (Ucp1). Previously, we reported that the TATA-binding protein Associated Factor 7L (Taf7l) is an important regulator of white adipose tissue (WAT) differentiation. Here, we show that Taf7l also serves as a molecular switch between brown fat and muscle lineages in vivo and in vitro. In adipose tissue, Taf7l containing TFIID complexes associate with PPAR to mediate DNA looping between distal enhancers and core promoter elements. Our findings suggest that presence of the tissue-specific Taf7l subunit in TFIID functions to promote long-range chromatin interactions during BAT lineage specification. mRNA-seq expression profiling wild type and Taf7l knockout interscapular brown adipose tissue (BAT)
2014-06-03 | E-GEOD-55797 | biostudies-arrayexpress