Combined α- and β-adrenergic receptor activation triggers thermogenesis by the futile creatine cycle.
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE207341 | GEO | 2022/09/08
REPOSITORIES: GEO
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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 | GSE207340 | 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: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:Mice and other small mammals heavily rely on UCP1-mediated non-shivering thermogenesis in the cold, and thus the unexpected cold resistance of UCP1-knockout (UCP1KO) mice has always been and still is an unresolved mystery inextricably intertwined with alternative means of thermogenesis and futile substrate cycles. Several potentially thermogenic futile substrate cycles in adipose tissue of WT and UCP1KO mice have been reported in the literature. We hypothesized that isoproterenol treatment of brown adipocytes from UCP1KO mice would cause an immediate acceleration of futile substrate cycling, and entail a consecutive upregulation of the involved enzymes to recruit additional capacity. In this study, we analyzed changes in the proteome of wild type (WT) and UCP1KO adipocytes during acute adrenergic stimulation to detect characteristic molecular signatures, which allowed us to narrow down our search to potential candidates related to Ca2+ and lipid metabolism.
2022-04-25 | PXD025854 | Pride
Project description:In obesity, misalignment of feeding time with the light/dark environment results in disruption of peripheral circadian clocks. Conversely, restricting feeding to the active period mitigates metabolic syndrome through mechanisms that remain unknown. Here we show that adipocyte thermogenesis is essential for the healthful metabolic response to time restricted feeding. Genetic enhancement of adipocyte thermogenesis through ablation of Zfp423 attenuates obesity caused by circadian mistimed high fat diet feeding through a mechanism involving creatine metabolism. Circadian control of adipocyte creatine metabolism underlies timing of diet-induced thermogenesis, and enhancement of adipocyte circadian rhythms through overexpression of the clock activator Bmal1 ameliorates metabolic complications during diet induced obesity. These findings establish creatine mediated diet-induced thermogenesis as a bioenergetic mechanism driving metabolic benefits during time-restricted feeding.
2022-10-24 | GSE181443 | GEO
Project description:The β-adrenergic receptor signaling pathway is a major component of adaptive thermogenesis in brown and white adipose tissue during cold acclimation. The β-AR activation highly induces transcriptional coactivator PGC-1α and its splice variant N-terminal (NT)-PGC-1α, promoting the transcription program of mitochondrial biogenesis and thermogenesis. In the present study, we evaluated the role of NT-PGC-1α in brown adipocyte energy metabolism by genome-wide profiling of NT-PGC-1α-responsive genes. Canonical pathway analysis revealed that a number of genes upregulated by NT-PGC-1α are highly enriched in mitochondrial pathways including fatty acid transport and β-oxidation, TCA cycle and electron transport system, thus reinforcing the crucial role of NT-PGC-1α in the enhancement of mitochondrial function. Moreover, gene expression profiling of NT-PGC-1α revealed activation of distinct metabolic pathways such as glucose, lipid and nucleotide metabolism and of signaling pathways such as RAR and PPAR-γ/RXRα activation in brown adipocytes. Together, our data strengthen our previous findings that NT-PGC-1α is a key regulator of mitochondrial oxidative metabolism and thermogenesis in brown adipocytes and further suggest that NT-PGC-1α influences a broader spectrum of thermogenic processes to meet cellular needs for adaptive thermogenesis. Two samples from two groups: NT-PGC-1α overexpression and empty vector. There are technical replicates (A and B) for each group. Two RNA samples were pooled for each group.
2015-08-07 | E-GEOD-71774 | biostudies-arrayexpress
Project description:Classic brown fat and inducible beige fat both dissipate chemical energy in the form of heat through the actions of mitochondrial uncoupling protein 1. This nonshivering thermogenesis is crucial for mammals as a defense against cold and obesity/diabetes. Cold is known to act indirectly through the sympathetic nervous systems and -adrenergic signaling, but here we report that cold temperature can directly activate a thermogenic gene program in adipocytes independent of -adrenergic signaling.
2018-08-16 | E-MTAB-4526 | biostudies-arrayexpress
Project description:Purpose: To investigate alterations in subcutaneous white adipose gene expression induced by genetic AMPK activation in vivo, in mice fed a chow or a high-fat diet. Methods: Subcutaneous white adipose tissue mRNA profiles of wild-type transgenic (WT-Tg) mice and mice expressing a gain-of-function AMPK mutant gamma1 subunit (D316A-Tg) were generated by deep sequencing. Results: RNA sequencing revealed over 3000 differentially expressed genes between WT-Tg and D316A-Tg subcutaneous white adipose tissue (WATsc) from mice fed a high fat diet (HFD), of which many were classified as 'skeletal muscle-associated'. Interestingly, uncoupling protein 1 (UCP1), associated with 'beige' adipocyte formation in WATsc, was not differentially expressed. On a chow diet, many differentially expressed genes were also identified, with gene ontology analysis identifiying glycolysis, TCA cycle and brown fat differentiation as highly enriched; key features of brown adipocyte identity. HFD-associated skeletal-muscle associated gene expression was either not significantly altered, or significantly down-regulated on a chow diet, indicating a diet-induced gene signature in D316A-Tg WATsc. Conclusions: Our study revealed gene signatures indicative of brown adipocyte development on a chow diet, where no overt metabolic phenotype was observed in gain-of-function animals. When fed a HFD, WATsc from D316A-Tg mice displayed a muscle-like gene signature, expressing key components of creatine and calcium thermogenic cycles including Ckmt2 (creatine kinase, mitochondrial 2) Atp2a1 (SERCA1-sarco/endoplasmic reticulum ATPase 1) and ryr1 (ryanodine receptor 1). UCP1 expression was not altered between WT-Tg and D316A-Tg mice fed a HFD. Our findings suggest a novel role for AMPK in the regulation of white adipocyte identity and a potentially novel cell population that, when metabolically challenged, preferrentially utilise muscle-like thermogenic futile cycles independent of UCP1 to mediate whole organism energy expenditure.
2019-02-01 | GSE120429 | GEO
Project description:Adrenergic stimulation of brown adipose tissue (BAT) activates thermogenesis, by uncoupling oxidative phosphorylation and enabling high rates of substrate oxidation. Moreover, adrenergic stimulation signals to the nucleus, inducing gene expression changes that increase BAT thermogenic and oxidative capacity. The purpose of this study was to determine the role of two orphan nuclear receptors, ERRα and ERRγ, in adipose tissue function in response to adrenergic stimulation. Here we identify ERRα and ERRγ as collectively critical effectors of the adrenergic induced transcriptional program in BAT. Mice lacking adipose ERRs (ERRαγAd-/-) have diminished oxidative and thermogenic capacity, and become rapidly hypothermic when exposed to cold. Notably, the ability of the β3-adrenergic agonist CL316,243 to expand BAT oxidative and thermogenic capacity, increase energy expenditure, promote weight loss, and improve glucose tolerance is lost in ERRαγAd-/-. At the transcriptional level, RNA sequencing experiments show that the bulk of the response of BAT to CL316,243 (>80% of CL316,243-induced genes) relies on ERRs. These findings establish ERRα and ERRγ as essential BAT regulators that act coordinately to relay adrenergic signals and expand the capacity for thermogenesis and energy expenditure.
2018-03-19 | GSE104285 | GEO
Project description:β-Adrenergic signaling is a core regulator of brown adipocyte function stimulating both lipolysis and transcription of thermogenic genes, thereby expanding the capacity for oxidative metabolism. Here we have used pharmacological inhibitors and a novel direct activator of lipolysis to acutely modulate the activity of lipases, thereby enabling us to uncover lipolysis-dependent signaling pathways downstream of β-adrenergic signaling in brown adipocytes. We show that induction of lipolysis leads to acute induction of several gene programs and is required for transcriptional regulation by β-adrenergic signals. Using machine-learning algorithms to infer causal transcription factors, we show that PPARs are key mediators of lipolysis-induced activation of genes involved in lipid metabolism and thermogenesis. Importantly, lipolysis also activates the unfolded protein response and regulates the core circadian transcriptional machinery independently of PPARs. Our results demonstrate that lipolysis generates important metabolic signals that exert profound pleiotropic effects on brown adipocyte transcription and function.
2022-05-21 | GSE203247 | GEO