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1.
Trends Endocrinol Metab ; 33(7): 493-506, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35491296

RESUMO

Brown adipose tissue (BAT) is often considered as a sink for nutrients to generate heat. However, when the complex hormonal and nervous inputs and intracellular signaling networks regulating substrate utilization are considered, BAT appears much more as a tightly controlled rheostat, regulating body temperature and balancing circulating nutrient levels. Here we provide an overview of key regulatory circuits, including the diurnal rhythm, determining glucose, fatty acid, and amino acid utilization and the interdependency of these nutrients in thermogenesis. Moreover, we discuss additional factors mediating sympathetic BAT activation beyond ß-adrenergic signaling and the limitations of glucose-based BAT activity measurements to foster a better understanding and interpretation of BAT activity data.


Assuntos
Adipócitos Marrons , Termogênese , Adipócitos Marrons/fisiologia , Tecido Adiposo Marrom/metabolismo , Glucose/metabolismo , Humanos , Termogênese/genética
2.
J Endocrinol Invest ; 45(1): 139-148, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34232475

RESUMO

PURPOSE: Caloric restriction (CR) and Roux-en-Y Gastric Bypass (RYGB) are considered effective means of body weight control, but the mechanism by which CR and RYGB protect against high-fat diet (HFD)-induced obesity remains elusive. The browning of white adipose tissue (WAT) is a potential approach to combat obesity. Here we assess whether browning of WAT is involved in CR- and RYGB-treatment. METHODS: The average size of adipocytes was determined by histological analysis. Expression of thermogenic genes in both human subjects and mice were measured by quantitative real-time PCR and immunohistochemical staining. RESULTS: The average size of adipocytes was bigger, while the expression of thermogenic genes such as uncoupling protein 1 (UCP1), nuclear factor erythroid-2 like 1 (NRF1) and PPARγ coactivator-1 α (PGC1α) were lower in the WAT of obese subjects when compared to lean controls. Both CR and RYGB promoted weight and fat loss. Increment of the average adipocytes size and down-regulation of thermogenic genes were significantly reversed by both CR and RYGB in the WAT of obese mice. CONCLUSIONS: Our findings showed that CR and RYGB significantly improved high-fat diet-induced lipid accumulation by promoting the browning of WAT.


Assuntos
Tecido Adiposo Marrom/fisiologia , Tecido Adiposo Branco/fisiologia , Restrição Calórica , Derivação Gástrica , Obesidade , Adipócitos Marrons/fisiologia , Adipócitos Brancos/fisiologia , Adulto , Animais , Transdiferenciação Celular , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Obesidade/dietoterapia , Obesidade/fisiopatologia , Obesidade/cirurgia
3.
Science ; 374(6571): 1066, 2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34822283
4.
Cells ; 10(9)2021 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-34571897

RESUMO

Despite peroxisomes being important partners of mitochondria by carrying out fatty acid oxidation in brown adipocytes, no clear evidence concerning peroxisome origin and way(s) of biogenesis exists. Herein we used methimazole-induced hypothyroidism for 7, 15, and 21 days to study peroxisomal remodeling and origin in rat brown adipocytes. We found that peroxisomes originated via both canonic, and de novo pathways. Each pathway operates in euthyroid control and over the course of hypothyroidism, in a time-dependent manner. Hypothyroidism increased the peroxisomal number by 1.8-, 3.6- and 5.8-fold on days 7, 15, and 21. Peroxisomal presence, their distribution, and their degree of maturation were heterogeneous in brown adipocytes in a Harlequin-like manner, reflecting differences in their origin. The canonic pathway, through numerous dumbbell-like and "pearls on strings" structures, supported by high levels of Pex11ß and Drp1, prevailed on day 7. The de novo pathway of peroxisomal biogenesis started on day 15 and became dominant by day 21. The transition of peroxisomal biogenesis from canonic to the de novo pathway was driven by increased levels of Pex19, PMP70, Pex5S, and Pex26 and characterized by numerous tubular structures. Furthermore, specific peroxisomal origin from mitochondria, regardless of thyroid status, indicates their mutual regulation in rat brown adipocytes.


Assuntos
Adipócitos Marrons/citologia , Hipotireoidismo/fisiopatologia , Peroxissomos/fisiologia , Adipócitos Marrons/fisiologia , Animais , Mitocôndrias/metabolismo , Oxirredução , PPAR alfa/metabolismo , PPAR gama/metabolismo , Ratos , Ratos Wistar , Fatores de Tempo
5.
Elife ; 102021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33944779

RESUMO

Adrenergic stimulation of brown adipocytes alters mitochondrial dynamics, including the mitochondrial fusion protein optic atrophy 1 (OPA1). However, direct mechanisms linking OPA1 to brown adipose tissue (BAT) physiology are incompletely understood. We utilized a mouse model of selective OPA1 deletion in BAT (OPA1 BAT KO) to investigate the role of OPA1 in thermogenesis. OPA1 is required for cold-induced activation of thermogenic genes in BAT. Unexpectedly, OPA1 deficiency induced fibroblast growth factor 21 (FGF21) as a BATokine in an activating transcription factor 4 (ATF4)-dependent manner. BAT-derived FGF21 mediates an adaptive response by inducing browning of white adipose tissue, increasing resting metabolic rates, and improving thermoregulation. However, mechanisms independent of FGF21, but dependent on ATF4 induction, promote resistance to diet-induced obesity in OPA1 BAT KO mice. These findings uncover a homeostatic mechanism of BAT-mediated metabolic protection governed in part by an ATF4-FGF21 axis, which is activated independently of BAT thermogenic function.


Assuntos
Tecido Adiposo Marrom/metabolismo , Regulação da Temperatura Corporal/genética , Fatores de Crescimento de Fibroblastos/metabolismo , GTP Fosfo-Hidrolases/genética , Deleção de Genes , Adipócitos Marrons/fisiologia , Tecido Adiposo Branco/fisiologia , Animais , Feminino , Fatores de Crescimento de Fibroblastos/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/genética
6.
Am J Physiol Endocrinol Metab ; 321(1): E47-E62, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33969705

RESUMO

Myoglobin (Mb) regulates O2 bioavailability in muscle and heart as the partial pressure of O2 (Po2) drops with increased tissue workload. Globin proteins also modulate cellular NO pools, "scavenging" NO at higher Po2 and converting NO2- to NO as Po2 falls. Myoglobin binding of fatty acids may also signal a role in fat metabolism. Interestingly, Mb is expressed in brown adipose tissue (BAT), but its function is unknown. Herein, we present a new conceptual model that proposes links between BAT thermogenic activation, concurrently reduced Po2, and NO pools regulated by deoxy/oxy-globin toggling and xanthine oxidoreductase (XOR). We describe the effect of Mb knockout (Mb-/-) on BAT phenotype [lipid droplets, mitochondrial markers uncoupling protein 1 (UCP1) and cytochrome C oxidase 4 (Cox4), transcriptomics] in male and female mice fed a high-fat diet (HFD, 45% of energy, ∼13 wk), and examine Mb expression during brown adipocyte differentiation. Interscapular BAT weights did not differ by genotype, but there was a higher prevalence of mid-large sized droplets in Mb-/-. COX4 protein expression was significantly reduced in Mb-/- BAT, and a suite of metabolic/NO/stress/hypoxia transcripts were lower. All of these Mb-/--associated differences were most apparent in females. The new conceptual model, and results derived from Mb-/- mice, suggest a role for Mb in BAT metabolic regulation, in part through sexually dimorphic systems and NO signaling. This possibility requires further validation in light of significant mouse-to-mouse variability of BAT Mb mRNA and protein abundances in wild-type mice and lower expression relative to muscle and heart.NEW & NOTEWORTHY Myoglobin confers the distinct red color to muscle and heart, serving as an oxygen-binding protein in oxidative fibers. Less attention has been paid to brown fat, a thermogenic tissue that also expresses myoglobin. In a mouse knockout model lacking myoglobin, brown fat had larger fat droplets and lower markers of mitochondrial oxidative metabolism, especially in females. Gene expression patterns suggest a role for myoglobin as an oxygen/nitric oxide-sensor that regulates cellular metabolic and signaling pathways.


Assuntos
Tecido Adiposo Marrom/fisiologia , Mioglobina/fisiologia , Adipócitos Marrons/fisiologia , Tecido Adiposo Marrom/química , Tecido Adiposo Marrom/ultraestrutura , Animais , Diferenciação Celular , Células Cultivadas , Dieta Hiperlipídica , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Expressão Gênica , Lipídeos/análise , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/fisiologia , Mioglobina/deficiência , Mioglobina/genética , Óxido Nítrico/metabolismo , Oxigênio/metabolismo , RNA Mensageiro/análise
7.
Nat Metab ; 3(4): 485-495, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33846638

RESUMO

Brown adipose tissue (BAT) and beige fat function in energy expenditure in part due to their role in thermoregulation, making these tissues attractive targets for treating obesity and metabolic disorders. While prolonged cold exposure promotes de novo recruitment of brown adipocytes, the exact sources of cold-induced thermogenic adipocytes are not completely understood. Here, we identify transient receptor potential cation channel subfamily V member 1 (Trpv1)+ vascular smooth muscle (VSM) cells as previously unidentified thermogenic adipocyte progenitors. Single-cell RNA sequencing analysis of interscapular brown adipose depots reveals, in addition to the previously known platelet-derived growth factor receptor (Pdgfr)α-expressing mesenchymal progenitors, a population of VSM-derived adipocyte progenitor cells (VSM-APC) expressing the temperature-sensitive cation channel Trpv1. We demonstrate that cold exposure induces the proliferation of Trpv1+ VSM-APCs and enahnces their differentiation to highly thermogenic adipocytes. Together, these findings illustrate the landscape of the thermogenic adipose niche at single-cell resolution and identify a new cellular origin for the development of brown and beige adipocytes.


Assuntos
Adipócitos/fisiologia , Temperatura Baixa , Células-Tronco Hematopoéticas/fisiologia , Músculo Liso Vascular/fisiologia , Canais de Cátion TRPV/fisiologia , Termogênese/fisiologia , Adipócitos Bege/fisiologia , Adipócitos Marrons/fisiologia , Tecido Adiposo Bege/metabolismo , Tecido Adiposo Marrom/fisiologia , Animais , Regulação da Temperatura Corporal/fisiologia , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Humanos , Células-Tronco Mesenquimais , Camundongos , Camundongos Endogâmicos C57BL , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/genética , Canais de Cátion TRPV/genética
8.
Nat Metab ; 3(4): 469-484, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33846639

RESUMO

Brown adipose tissue can expend large amounts of energy, and therefore increasing its size or activity is a promising therapeutic approach to combat metabolic disease. In humans, major deposits of brown fat cells are found intimately associated with large blood vessels, corresponding to perivascular adipose tissue (PVAT). However, the cellular origins of PVAT are poorly understood. Here, we determine the identity of perivascular adipocyte progenitors in mice and humans. In mice, thoracic PVAT develops from a fibroblastic lineage, consisting of progenitor cells (Pdgfra+, Ly6a+ and Pparg-) and preadipocytes (Pdgfra+, Ly6a+ and Pparg+), which share transcriptional similarity with analogous cell types in white adipose tissue. Interestingly, the aortic adventitia of adult animals contains a population of adipogenic smooth muscle cells (Myh11+, Pdgfra- and Pparg+) that contribute to perivascular adipocyte formation. Similarly, human PVAT contains presumptive fibroblastic and smooth muscle-like adipocyte progenitor cells, as revealed by single-nucleus RNA sequencing. Together, these studies define distinct populations of progenitor cells for thermogenic PVAT, providing a foundation for developing strategies to augment brown fat activity.


Assuntos
Adipócitos Marrons/fisiologia , Tecido Adiposo Marrom/fisiologia , Linhagem da Célula/fisiologia , Termogênese/fisiologia , Adipócitos Brancos/fisiologia , Adipogenia/fisiologia , Tecido Adiposo Marrom/crescimento & desenvolvimento , Animais , Animais Recém-Nascidos , Aorta/citologia , Aorta/fisiologia , Vasos Sanguíneos/fisiologia , Linhagem da Célula/genética , Fibroblastos/fisiologia , Regulação da Expressão Gênica/fisiologia , Humanos , Recém-Nascido , Camundongos , Camundongos Endogâmicos C57BL , Miócitos de Músculo Liso/fisiologia , Células-Tronco/fisiologia , Termogênese/genética
9.
Diabetes ; 70(6): 1317-1333, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33795413

RESUMO

Brown and beige adipocytes are characterized as thermogenic adipocytes and have great potential for treating obesity and associated metabolic diseases. In this article, we identify a conserved mammalian lysine 79 of histone H3 (H3K79) methyltransferase, disruptor of telomeric silencing-1 like (DOT1L), as a new epigenetic regulator that controls thermogenic adipocyte differentiation and function. We show that deletion of DOT1L in thermogenic adipocytes potently protects mice from diet-induced obesity, improves glucose homeostasis, alleviates hepatic steatosis, and facilitates adaptive thermogenesis in vivo. Loss of DOT1L in primary preadipocytes significantly promotes brown and beige adipogenesis and thermogenesis in vitro. Mechanistically, DOT1L epigenetically regulates the brown adipose tissue-selective gene program by modulating H3K79 methylation, in particular H3K79me2 modification. Thus, our study demonstrates that DOT1L exerts an important role in energy homeostasis by regulating thermogenic adipocyte differentiation and function.


Assuntos
Adipogenia/genética , Histona-Lisina N-Metiltransferase/fisiologia , Termogênese/genética , Adipócitos Bege/fisiologia , Adipócitos Marrons/fisiologia , Animais , Diferenciação Celular/genética , Células Cultivadas , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Processamento de Proteína Pós-Traducional/genética
10.
Nat Metab ; 3(2): 228-243, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33619380

RESUMO

Obesity is a major risk factor for cardiometabolic diseases. Nevertheless, a substantial proportion of individuals with obesity do not suffer cardiometabolic comorbidities. The mechanisms that uncouple adiposity from its cardiometabolic complications are not fully understood. Here, we identify 62 loci of which the same allele is significantly associated with both higher adiposity and lower cardiometabolic risk. Functional analyses show that the 62 loci are enriched for genes expressed in adipose tissue, and for regulatory variants that influence nearby genes that affect adipocyte differentiation. Genes prioritized in each locus support a key role of fat distribution (FAM13A, IRS1 and PPARG) and adipocyte function (ALDH2, CCDC92, DNAH10, ESR1, FAM13A, MTOR, PIK3R1 and VEGFB). Several additional mechanisms are involved as well, such as insulin-glucose signalling (ADCY5, ARAP1, CREBBP, FAM13A, MTOR, PEPD, RAC1 and SH2B3), energy expenditure and fatty acid oxidation (IGF2BP2), browning of white adipose tissue (CSK, VEGFA, VEGFB and SLC22A3) and inflammation (SH2B3, DAGLB and ADCY9). Some of these genes may represent therapeutic targets to reduce cardiometabolic risk linked to excess adiposity.


Assuntos
Adiposidade/genética , Loci Gênicos/genética , Estudo de Associação Genômica Ampla , Obesidade/genética , Adipócitos/metabolismo , Adipócitos Marrons/fisiologia , Adipócitos Brancos/fisiologia , Tecido Adiposo/metabolismo , Alelos , Metabolismo Energético/fisiologia , Ácidos Graxos/metabolismo , Glucose/metabolismo , Humanos , Insulina/metabolismo , Família Multigênica/genética , Obesidade/complicações , Medição de Risco , Transdução de Sinais/fisiologia
11.
Life Sci ; 265: 118762, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33189825

RESUMO

AIMS: This study is to investigate the role of adenovirus type 36 (Ad36) in inducing differentiation of human adipose-derived stem cells (hADSCs) into brown adipocytes. MAIN METHODS: The hADSCs were induced to differentiate into adipocytes by a cocktail method and Ad36, respectively. They were collected on the 2nd, 4th, 6th, and 8th day, respectively. LncRNA ROR was silenced by siRNA. RT-qPCR and Western-blot were used to detect the mRNA and protein levels. Transmission electron microscopy was used to observe the mitochondria. KEY FINDINGS: The mRNA and protein expression levels of LncRNA ROR, Cidea, Dio2, Fgf21, Ucp1, Prdm16, Cox5b, Atp5o, Atp6, and Nd2 in the Ad36 induction group were significantly higher than those in the cocktail induction group. The expression levels of Leptin mRNA and protein in the Ad36 induction group were significantly lower than those in the cocktail induction group. After siRNA knockdown of LncRNA ROR, mRNA and protein expression levels of Cidea, Dio2, Fgf21, Ucp1, Prdm16, Cox5b, Atp5o, Atp6 and Nd2 were significantly lower than the control group during the induction of hADSC differentiation into adipocytes by Ad36. Additionally, mitochondria in the Ad36 induction group was increased compared to that in the cocktail induction group. SIGNIFICANCE: Ad36 may promote the differentiation of hADSCs into brown adipocytes by up-regulating LncRNA ROR.


Assuntos
Adenoviridae/metabolismo , Infecções por Adenovirus Humanos/metabolismo , Adipócitos Marrons/virologia , Células-Tronco Mesenquimais/metabolismo , RNA Longo não Codificante/metabolismo , Adipócitos Marrons/metabolismo , Adipócitos Marrons/fisiologia , Adipócitos Marrons/ultraestrutura , Western Blotting , Diferenciação Celular , Regulação da Expressão Gênica , Inativação Gênica , Humanos , Microscopia Eletrônica de Transmissão , Mitocôndrias/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
12.
STAR Protoc ; 1(3): 100118, 2020 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-33377014

RESUMO

Studying brown and brite adipose tissue requires precise and reliable quantification of cellular thermogenesis. This protocol describes the isolation of primary murine pre-adipocytes, differentiation into thermogenic brown and brite adipocytes, and subsequent oxygen consumption analysis. Commonly applied procedures only measure basal and maximal proton leak-linked oxygen consumption but not explicitly uncoupling protein 1 (UCP1)-dependent respiration. Meaningful oxygen consumption analyses require (1) the activation of UCP1, (2) control over intracellular free-fatty-acid levels, and (3) inhibition of ATP-consuming futile cycles. For complete details on the use and execution of this protocol, please refer to Li et al. (2014, 2017, 2018) and Schweizer et al. (2018).


Assuntos
Adipócitos Bege/metabolismo , Adipócitos Marrons/metabolismo , Cultura Primária de Células/métodos , Adipócitos Bege/fisiologia , Adipócitos Marrons/fisiologia , Tecido Adiposo Bege/metabolismo , Tecido Adiposo Marrom/metabolismo , Animais , Diferenciação Celular , Células Cultivadas , Camundongos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Consumo de Oxigênio , Termogênese/fisiologia
13.
Mol Metab ; 42: 101097, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33049408

RESUMO

OBJECTIVE: Metainflammation is a chronic low-grade inflammatory state induced by obesity and associated comorbidities, including peripheral insulin resistance. Brown adipose tissue (BAT), a therapeutic target against obesity, is an insulin target tissue sensitive to inflammation. Therefore, it is necessary to find strategies to protect BAT against the effects of inflammation in energy balance. In this study, we explored the impact of moderate sirtuin 1 (SIRT1) overexpression on insulin sensitivity and ß-adrenergic responses in BAT and brown adipocytes (BA) under pro-inflammatory conditions. METHODS: The effect of inflammation on BAT functionality was studied in obese db/db mice and lean wild-type (WT) mice or mice with moderate overexpression of SIRT1 (SIRT1Tg+) injected with a low dose of bacterial lipopolysaccharide (LPS) to mimic endotoxemia. We also conducted studies on differentiated BA (BA-WT and BA-SIRT1Tg+) exposed to a macrophage-derived pro-inflammatory conditioned medium (CM) to evaluate the protection of SIRT1 overexpression in insulin signaling and glucose uptake, mitochondrial respiration, fatty acid oxidation (FAO), and norepinephrine (NE)-mediated-modulation of uncoupling protein-1 (UCP-1) expression. RESULTS: BAT from the db/db mice was susceptible to metabolic inflammation manifested by the activation of pro-inflammatory signaling cascades, increased pro-inflammatory gene expression, tissue-specific insulin resistance, and reduced UCP-1 expression. Impairment of insulin and noradrenergic responses were also found in the lean WT mice upon LPS injection. In contrast, BAT from the mice with moderate overexpression of SIRT1 (SIRT1Tg+) was protected against LPS-induced activation of pro-inflammatory signaling, insulin resistance, and defective thermogenic-related responses upon cold exposure. Importantly, the decline in triiodothyronine (T3) levels in the circulation and intra-BAT after exposure of the WT mice to LPS and cold was markedly attenuated in the SIRT1Tg+ mice. In vitro BA experiments in the two genotypes revealed that upon differentiation with a T3-enriched medium and subsequent exposure to a macrophage-derived pro-inflammatory CM, only BA-SIRT1Tg+ fully recovered insulin and noradrenergic responses. CONCLUSIONS: This study has ascertained the benefit of the moderate overexpression of SIRT1 to confer protection against defective insulin and ß-adrenergic responses caused by BAT inflammation. Our results have potential therapeutic value in combinatorial therapies for BAT-specific thyromimetics and SIRT1 activators to combat metainflammation in this tissue.


Assuntos
Tecido Adiposo Marrom/metabolismo , Sirtuína 1/metabolismo , Adipócitos/metabolismo , Adipócitos/fisiologia , Adipócitos Marrons/metabolismo , Adipócitos Marrons/fisiologia , Tecido Adiposo/metabolismo , Tecido Adiposo Marrom/fisiologia , Animais , Metabolismo Energético , Feminino , Expressão Gênica/genética , Regulação da Expressão Gênica/genética , Inflamação/prevenção & controle , Insulina/metabolismo , Resistência à Insulina/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Obesidade/metabolismo , Receptores Adrenérgicos beta/metabolismo , Sirtuína 1/genética , Sirtuína 1/fisiologia , Termogênese/efeitos dos fármacos , Proteína Desacopladora 1/metabolismo
14.
Artigo em Inglês | MEDLINE | ID: mdl-33042008

RESUMO

New treatments for obesity and associated metabolic disease are increasingly warranted with the growth of the obesity pandemic. Brown adipose tissue (BAT) may represent a promising therapeutic target to treat obesity, as this tissue has been shown to regulate energy expenditure through non-shivering thermogenesis. Three different strategies could be employed for therapeutic targeting of human thermogenic adipocytes: increasing BAT mass through stimulation of BAT progenitors, increasing BAT function through regulatory pathways, and increasing WAT browning through promotion of beige adipocyte formation. However, these strategies require deeper understanding of human brown and beige adipocytes. While murine studies have greatly increased our understanding of BAT, it is becoming clear that human BAT does not exactly resemble that of the mouse, highlighting the need for human in vitro models of brown adipocytes. Several different human brown adipocyte models will be discussed here, along with the potential to improve brown adipocyte culture through recreation of the BAT microenvironment.


Assuntos
Adipócitos Marrons/fisiologia , Tecido Adiposo Marrom/fisiologia , Metabolismo Energético/fisiologia , Termogênese/fisiologia , Humanos , Técnicas In Vitro
15.
PLoS Genet ; 16(9): e1009044, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32991581

RESUMO

The transcription factor nuclear factor I-A (NFIA) is a regulator of brown adipocyte differentiation. Here we show that the C-terminal 17 amino acid residues of NFIA (which we call pro#3 domain) are required for the transcriptional activity of NFIA. Full-length NFIA-but not deletion mutant lacking pro#3 domain-rescued impaired expression of PPARγ, the master transcriptional regulator of adipogenesis and impaired adipocyte differentiation in NFIA-knockout cells. Mechanistically, the ability of NFIA to penetrate chromatin and bind to the crucial Pparg enhancer is mediated through pro#3 domain. However, the deletion mutant still binds to Myod1 enhancer to repress expression of MyoD, the master transcriptional regulator of myogenesis as well as proximally transcribed non-coding RNA called DRReRNA, via competition with KLF5 in terms of enhancer binding, leading to suppression of myogenic gene program. Therefore, the negative effect of NFIA on the myogenic gene program is, at least partly, independent of the positive effect on PPARγ expression and its downstream adipogenic gene program. These results uncover multiple ways of action of NFIA to ensure optimal regulation of brown and beige adipocyte differentiation.


Assuntos
Adipócitos Bege/citologia , Adipócitos Marrons/citologia , Adipogenia/fisiologia , Desenvolvimento Muscular/fisiologia , Fatores de Transcrição NFI/metabolismo , Adipócitos Bege/fisiologia , Adipócitos Marrons/fisiologia , Adipogenia/genética , Animais , Diferenciação Celular/genética , Cromatina/genética , Cromatina/metabolismo , Regulação da Expressão Gênica , Células HEK293 , Humanos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Desenvolvimento Muscular/genética , Proteína MyoD/genética , Miogenina/genética , Fatores de Transcrição NFI/genética , PPAR gama/genética , PPAR gama/metabolismo , Prolina , Domínios Proteicos
16.
Proc Natl Acad Sci U S A ; 117(36): 22413-22422, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32839323

RESUMO

Brown and beige adipocytes harbor the thermogenic capacity to adapt to environmental thermal or nutritional changes. Histone methylation is an essential epigenetic modification involved in the modulation of nonshivering thermogenesis in adipocytes. Here, we describe a molecular network leading by KMT5c, a H4K20 methyltransferase, that regulates adipocyte thermogenesis and systemic energy expenditure. The expression of Kmt5c is dramatically induced by a ß3-adrenergic signaling cascade in both brown and beige fat cells. Depleting Kmt5c in adipocytes in vivo leads to a decreased expression of thermogenic genes in both brown and subcutaneous (s.c.) fat tissues. These mice are prone to high-fat-diet-induced obesity and develop glucose intolerance. Enhanced transformation related protein 53 (Trp53) expression in Kmt5c knockout (KO) mice, that is due to the decreased repressive mark H4K20me3 on its proximal promoter, is responsible for the metabolic phenotypes. Together, these findings reveal the physiological role for KMT5c-mediated H4K20 methylation in the maintenance and activation of the thermogenic program in adipocytes.


Assuntos
Adipócitos Bege/fisiologia , Adipócitos Marrons/fisiologia , Histona-Lisina N-Metiltransferase , Termogênese/fisiologia , Proteína Supressora de Tumor p53/metabolismo , Adipócitos Bege/metabolismo , Adipócitos Marrons/metabolismo , Animais , Dieta Hiperlipídica , Feminino , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Masculino , Camundongos , Camundongos Knockout , Proteína Supressora de Tumor p53/genética
17.
Food Res Int ; 136: 109303, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32846515

RESUMO

As the major biologically active constituents in Ganoderma species, Ganoderma triterpenoids (GTs) also showed potential anti-obesity effect in recent reports. To further elucidate the anti-obesity effect of GTs, four new compounds Ganoderenses H-K (1-4) and four known compounds (5-8) from Ganoderma resinaceum were determined by extensive spectroscopic analysis. The absolute configurations of Ganoderenses H (1), I (2), and Resinacein S (Res S; 5) were confirmed for the first time by X-ray crystallographic analysis. Then the effects of these triterpenoids on brown/beige adipocytes were further analyzed in vitro. Our results may be summarized as follows: (1) Res S reduced lipid droplets size by regulating lipid metabolism, but not affect the differentiation of C3H10T1/2 cells. (2) Res S increased the expression of brown and beige adipocytes markers and enhanced the activity of brown and beige adipocytes (e.g., increased ß-oxidation and pro-lipolytic activities et al.) in differentiated C3H10T1/2 cells. (3) Res S induced mitochondrial biogenesis and increased mitochondrial OCR in differentiated C3H10T1/2 cells. In conclusion, Res S is potential for activating the function of brown and beige adipocytes, thus having potential therapeutic implications for obesity and associated metabolic diseases.


Assuntos
Adipócitos Bege/efeitos dos fármacos , Adipócitos Marrons/efeitos dos fármacos , Ganoderma/química , Triterpenos/farmacologia , Adipócitos Bege/fisiologia , Adipócitos Marrons/fisiologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Carpóforos/química , Metabolismo dos Lipídeos/efeitos dos fármacos , Obesidade/tratamento farmacológico , Obesidade/prevenção & controle
18.
Am J Physiol Endocrinol Metab ; 319(4): E667-E677, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32799658

RESUMO

MicroRNA-30a (miR-30a) impacts adipocyte function, and its expression in white adipose tissue (WAT) correlates with insulin sensitivity in obesity. Bioinformatic analysis demonstrates that miR-30a expression contributes to 2% of all miRNA expression in human tissues. However, molecular mechanisms of miR-30a function in fat cells remain unclear. Here, we expanded our understanding of how miR-30a expression contributes to antidiabetic peroxisome proliferator-activated receptor-γ (PPARγ) agonist activity and metabolic functions in adipocytes. We found that WAT isolated from diabetic patients shows reduced miR-30a levels and diminished expression of the canonical PPARγ target genes ADIPOQ and FABP4 relative to lean counterparts. In human adipocytes, miR-30a required PPARγ for maximal expression, and the PPARγ agonist rosiglitazone robustly induced miR-30a but not other miR-30 family members. Transcriptional activity studies in human adipocytes also revealed that ectopic expression of miR-30a enhanced the activity of rosiglitazone coupled with higher expression of fatty acid and glucose metabolism markers. Diabetic mice that overexpress ectopic miR-30a in subcutaneous WAT display durable reductions in serum glucose and insulin levels for more than 30 days. In agreement with our in vitro findings, RNA-seq coupled with Gene Set Enrichment Analysis (GSEA) suggested that miR-30a enabled activation of the beige fat program in vivo, as evidenced by enhanced mitochondrial biogenesis and induction of UCP1 expression. Metabolomic and gene expression profiling established that the long-term effects of ectopic miR-30a expression enable accelerated glucose metabolism coupled with subcutaneous WAT hyperplasia. Together, we establish a putative role of miR-30a in mediating PPARγ activity and advancing metabolic programs of white to beige fat conversion.


Assuntos
Adipócitos Marrons/fisiologia , Redes Reguladoras de Genes/genética , MicroRNAs/fisiologia , Adipócitos Brancos/metabolismo , Animais , Glicemia/metabolismo , Células Cultivadas , Proteínas de Ligação a Ácido Graxo/metabolismo , Humanos , Hipoglicemiantes/farmacologia , Resistência à Insulina/genética , Metabolômica , Camundongos , MicroRNAs/genética , Oligopeptídeos/metabolismo , Biogênese de Organelas , PPAR gama/agonistas , Rosiglitazona/farmacologia
19.
J Mol Endocrinol ; 65(3): 97-107, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32755999

RESUMO

White adipose tissue (WAT) browning may have beneficial effects for treating metabolic syndrome. miRNA are important regulators of the differentiation, development, and function of brown and beige adipocytes. Here, we found that the cold-inducible miRNA17-92 cluster is enriched in brown adipose tissue (BAT) compared with WAT. Overexpression of the miR17-92 cluster in C3H10T1/2 cells, a mouse mesenchymal stem cell line, enhanced the thermogenic capacity of adipocytes. Furthermore, we observed a significant reduction in adiposity in adipose tissue-specific miR17-92 cluster transgenic (TG) mice. This finding is partly explained by dramatic increases in white fat browning and energy expenditure. Interestingly, the miR17-92 cluster stimulated WAT browning without altering BAT activity in mice. In addition, when we removed the intrascapular BAT (iBAT), the TG mice could maintain their body temperature well under cold exposure. At the molecular level, we found that the miR17-92 cluster targets Rb1, a beige cell repressor in WAT. The present study reveals a critical role for the miR17-92 cluster in regulating WAT browning. These results may be helpful for better understanding the function of beige fat, which could compensate for the lack of BAT in humans, and may open new avenues for combatting metabolic syndrome.


Assuntos
Adipócitos Marrons/fisiologia , Adipócitos Brancos/fisiologia , Transdiferenciação Celular/genética , MicroRNAs/genética , Células 3T3-L1 , Adipócitos Bege/fisiologia , Tecido Adiposo Marrom/fisiologia , Tecido Adiposo Branco/fisiologia , Animais , Células Cultivadas , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Família Multigênica/fisiologia , Termogênese/genética
20.
Phytomedicine ; 78: 153292, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32777487

RESUMO

BACKGROUND: Brown adipose tissue (BAT) activation is a promising therapeutic target to treat hyperlipidemia with obesity. Huang-Qi San (HQS), an traditional Chinese medicine, can ameliorate hyperlipidemia with obesity, but its mechanism of action (MOA) is not understood. PURPOSE: To articulate the MOA for HQS with animal models. METHODS: The main chemical constituents of HQS were identified by high-performance liquid chromatography (HPLC) based assay. Hyperlipidemia with obesity rat models induced by high-fat diet were employed in the study. The levels of the fasting plasma glucose (FPG), triglyceride (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol (HDL-C) were measured to evaluate the ability of HQS to ameliorate hyperlipidemia with obesity. Pathological analyses of organs were conducted with Oil Red O staining, hematoxylin-eosin (H&E) staining and transmission electron microscopy. The expression of mRNAs related to thermogenic genes, fatty acid oxidation-related genes and mitochondria biogenic genes were examined by quantitative real-time PCR. The protein expressions of uncoupling protein 1 (UCP1) were investigated by immunohistochemistry and western blot. Simultaneously, the protein expression of PR domain containing 16 (PRDM16), ATP synthase F1 subunit alpha (ATP5A) was detected by western blot. RESULTS: HQS ameliorates metabolic disorder, lipid ectopic deposition, obesity and maintained glucose homeostasis in hyperlipidemia with obesity rats. HQS can significantly increase the number of mitochondria and reduced the size of the intracellular lipid droplets in BAT, and increase the expression of BAT activation-related genes (UCP1, PGC1α, PGC1ß, Prdm16, CD137, TBX1, CPT1a, PPARα, Tfam, NRF1 and NRF2) in vivo. Furthermore, UCP1, PRDM16 and ATP5A proteins of BAT were increased. CONCLUSION: HQS can activate BAT and browning of S-WAT (subcutaneous white adipose tissue) through activating the PRDM16/PGC1α/UCP1 pathway, augmenting mitochondrial biogenesis and fatty acid oxidation to increase thermogenesis and energy expenditure, resulting in a significant amelioration of hyperlipidemia with obesity. Therefore, HQS is an effective therapeutic medicine for the treatment of hyperlipidemia with obesity.


Assuntos
Adipócitos Marrons/efeitos dos fármacos , Adipócitos Brancos/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Hiperlipidemias/tratamento farmacológico , Adipócitos Marrons/fisiologia , Adipócitos Brancos/metabolismo , Adipócitos Brancos/fisiologia , Animais , Astragalus propinquus , Dieta Hiperlipídica/efeitos adversos , Medicamentos de Ervas Chinesas/química , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hiperlipidemias/etiologia , Hiperlipidemias/patologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Obesidade/tratamento farmacológico , Obesidade/etiologia , Ratos Sprague-Dawley , Termogênese/efeitos dos fármacos
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