Brown adipocytes proteome upon acute adrenergic stimulation
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Fusion Lumos
ORGANISM(S): Mus Musculus (mouse)
TISSUE(S): Adipose Tissue
SUBMITTER: 
Piero Giansanti
LAB HEAD: Bernhard Kuster
PROVIDER: PXD025854 | Pride | 2022-04-25
REPOSITORIES: Pride
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Project description:Adaptive thermogenesis has attracted much attention because of its ability to raise systemic energy expenditure and counter obesity and diabetes. Recent data have indicated that thermogenic fat cells utilize creatine to stimulate futile substrate cycling, dissipating chemical energy as heat. This model was based on the super-stoichiometric relationship between creatine added to mitochondria and O2 consumed, and this project aims at providing direct evidence for the molecular basis of this futile creatine cycling activity. In this project, we found that thermogenic fat cells contain robust phosphocreatine hydrolase (PCr’ase) activity, attributable to tissue-nonspecific alkaline phosphatase (TNAP), which was identified by the quantitative mass spectrometric analysis of a purified mitochondrial protein fraction containing the PCr’ase activity. TNAP hydrolyzes phosphocreatine to initiate a futile cycle of creatine dephosphorylation and phosphorylation; it is localized to mitochondria of thermogenic fat cells, where the futile creatine cycling occurs. Furthermore, we demonstrated in this project the essential role of TNAP in activating the futile creatine cycling and increasing whole body energy expenditure using genetic and pharmacological approaches. We also found that the genetic depletion of TNAP in murine adipose tissue causes rapid-onset obesity, with no change in movement or feeding behavior of the animals. Using quantitative mass spectrometry, we showed that genetic depletion of TNAP causes an upregulation of UCP1, as well as other proteins involved in oxidative metabolism, to compensate for a dampened thermogenesis. In summary, the data we acquired in this project illustrate the critical role of TNAP as a phosphocreatine phosphatase in the futile creatine cycling and adipose thermogenesis.
2022-02-17 | PXD025032 | Pride
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:Obesity is a polygenic disorder with variable penetrance in the general population. Brown adipose tissue (BAT) is a major regulator of energy expenditure and metabolic physiology due to a specialized proteome that orchestrates futile metabolic cycles, which could be leveraged to treat obesity. However, nearly all mechanistic studies of BAT protein function occur in a single inbred mouse strain, which has limited understanding of generalizable mechanisms of BAT regulation over metabolism. Here we perform deep quantitative multiplexed proteomics of BAT across a cohort of 163 genetically defined Diversity Outbred (DO) mice, a model that parallels the genetic and phenotypic variation found in the human population. Leveraging the high variation afforded by this model, we define the functional architecture of the outbred BAT proteome, comprising 10,479 proteins. In doing so, we assign novel co-operative functions to 2,578 proteins with 780 established protein networks. We demonstrate that this analytic framework enables systematic discovery of regulators of BAT function, exemplified by uncovering SFXN5 and LETMD1 as modulators of UCP1-dependent thermogenesis. We also identify 638 proteins that underlie protection from, or sensitivity to, at least one parameter of metabolic disease. From this basis, we identify the Na+/K+- ATPase α2 subunit as an inhibitor of BAT energy expenditure, that increases adiposity through antagonism of calcium influx-dependent activation of thermogenic effectors. We provide this Outbred Proteomic Architecture as a resource for understanding conserved mechanisms of BAT regulation over metabolic physiology.
2022-11-08 | PXD036947 | Pride
Project description:Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver pathology worldwide and is intimately linked with obesity and type 2 diabetes. Liver inflammation is a hallmark of NAFLD and is thought to contribute to tissue fibrosis and disease pathogenesis. Uncoupling protein 1 (UCP1) is exclusively expressed in brown and beige adipocytes and has been extensively studied for its capacity to elevate thermogenesis and reverse obesity. Here we identify an endocrine pathway regulated by UCP1 that antagonizes liver inflammation and pathology, independent of effects on obesity. We show that, without UCP1, brown and beige fat exhibit a diminished capacity to clear succinate from the circulation. Moreover, UCP1KO mice exhibit elevated extracellular succinate in liver tissue that drives inflammation through ligation of its cognate receptor succinate receptor 1 (SUCNR1) in liver-resident stellate cell and macrophage populations. Conversely, increasing brown and beige adipocyte content in mice antagonizes SUCNR1-dependent inflammatory signaling in the liver. We show that this UCP1-succinate-SUCNR1 axis is necessary to regulate liver immune cell infiltration and pathology, and systemic glucose intolerance in an obesogenic environment. As such, the therapeutic utility of brown and beige adipocytes, and UCP1, extends beyond thermogenesis and may be leveraged to antagonize NAFLD and SUCNR1-dependent liver inflammation.
2022-02-17 | PXD024717 | Pride
Project description:Uncoupling protein 1 (UCP1) is thought to be a major regulator of whole-body energy expenditure and metabolic homeostasis. However, the widely employed UCP1 loss of function model has recently been shown to have destructive effects on the entire electron transport chain of thermogenic fat. As such, the role of UCP1 in metabolic regulation in vivo remains unclear. We recently identified cysteine-253 as an allosteric site on UCP1 that elevates protein activity upon covalent modification. Here we examine the physiological importance of this site through the generation of a UCP1 cysteine-253 null mouse (UCP1 C253A), the first genetic model for selective disruption of UCP1 in vivo. UCP1 C253A mice exhibit significantly compromised thermogenic responses but display no measurable effect on fat accumulation in an obesogenic environment. Unexpectedly, instead we find that lack of cysteine-253 results in substantial immune cell infiltration and inflammatory pathology in adipose tissues of male, but not female mice. Together, our results establish the UCP1 cysteine-253 activation site as a regulator of acute thermogenesis and sex-dependent adipose tissue inflammation.
2021-12-15 | PXD029270 | 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:Differentiation of brown adipocytes is a crucial process for adaptive thermogenesis, which is stimulated by various factors. We found robust browning of inguinal white adipose tissue in UCP1/ApoE-DKO mice, but not in ApoE-KO mice, under high-fat diet condition. We used microarray to determine the genes specifically regulated in the browning white adipose tissue in UCP1/ApoE-DKO mice.
2018-10-01 | GSE95273 | GEO
Project description:Noradrenaline regulates cold-stimulated adipocyte thermogenesis. Aside from cAMP signaling downstream of β-adrenergic receptor (βAR) activation, how noradrenaline promotes thermogenic output is still not fully understood. Here, we show that coordinated α1-adrenergic receptor (α1AR) and β3AR signaling induces the expression of thermogenic genes of the futile creatine cycle, and that EBFs, ERRs, and PGC1α are required for this response in vivo. Noradrenaline triggers physical and functional coupling between the α1AR subtype (ADRA1A) to Gαq to promote adipocyte thermogenesis in a manner that is dependent on the effector proteins of the futile creatine cycle, creatine kinase b (CKB) and tissue-nonspecific alkaline phosphatase (TNAP). Combined Gαq and Gαs signaling selectively in adipocytes promotes a continual rise in whole-body energy expenditure, and CKB is required for this effect. Thus, the ADRA1A-Gαq-futile creatine cycle axis is a key regulator of facultative and adaptive thermogenesis.
2022-09-08 | GSE207341 | GEO
Project description:Noradrenaline regulates cold-stimulated adipocyte thermogenesis. Aside from cAMP signaling downstream of β-adrenergic receptor (βAR) activation, how noradrenaline promotes thermogenic output is still not fully understood. Here, we show that coordinated α1-adrenergic receptor (α1AR) and β3AR signaling induces the expression of thermogenic genes of the futile creatine cycle, and that EBFs, ERRs, and PGC1α are required for this response in vivo. Noradrenaline triggers physical and functional coupling between the α1AR subtype (ADRA1A) to Gαq to promote adipocyte thermogenesis in a manner that is dependent on the effector proteins of the futile creatine cycle, creatine kinase b (CKB) and tissue-nonspecific alkaline phosphatase (TNAP). Combined Gαq and Gαs signaling selectively in adipocytes promotes a continual rise in whole-body energy expenditure, and CKB is required for this effect. Thus, the ADRA1A-Gαq-futile creatine cycle axis is a key regulator of facultative and adaptive thermogenesis.
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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