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1.
Gene ; 766: 145155, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32950634

RESUMO

Expression of browning genes are lower in both humans and animals with type 2 diabetes (T2D). This study aims at determining effects of long-term nitrate administration on protein and mRNA levels of uncoupling protein 1 (UCP1), peroxisome proliferator activated receptor gamma (PPAR-γ), and PPAR-γ coactivator 1 alpha (PGC1-α) in epididymal adipose tissue (eAT) of rats with T2D. Male Wistar rats were divided into 4 groups (n = 6/group): Control, diabetes, control + nitrate (CN), and diabetes + nitrate (DN). T2D was induced using high fat diet combined with a low-dose of streptozotocin (30 mg/kg body weight). Sodium nitrate was administrated at a dose of 100 mg/L for 6 months in nitrate-treated rats. Fasting serum glucose and insulin concentrations were measured at months 0 (i.e. at start of the protocol), 3, and 6. At month 6, protein and mRNA levels of UCP1, PPAR-γ, and PGC1-α were measured in eAT samples. In addition, tissue concentration of cyclic guanosine monophosphate (cGMP) was measured and histological analyses were done at month 6. In rats with T2D, 6-month administration of nitrate decreased serum glucose and insulin concentrations by 13% and 23%, respectively and increased cGMP level by 85%. Rats with T2D had lower mRNA and protein levels of PPAR-γ (62%, P < 0.0001 and 18%, P = 0.0472), PGC1-α (49%, P = 0.0019 and 21%, P = 0.0482), and UCP1 (35%, P = 0.0613 and 30%, P = 0.0031) in eAT; 6-month nitrate administration restored these decreased levels to near control values. In addition, nitrate increased adipocyte density by 193% and decreased adipocyte area by 53% in rats with T2D. In conclusion, long-term low-dose nitrate administration increased mRNA and protein expressions of browning genes in white adipose tissue of male rats with T2D; these findings partly explain favorable metabolic effects of nitrate administration in diabetes.


Assuntos
Adipócitos Marrons/efeitos dos fármacos , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Branco/efeitos dos fármacos , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Tipo 2/genética , Epididimo/efeitos dos fármacos , Nitratos/administração & dosagem , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Adipócitos Marrons/metabolismo , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Animais , Glicemia/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Epididimo/metabolismo , Glucose/metabolismo , Insulina/sangue , Masculino , PPAR gama/genética , PPAR gama/metabolismo , RNA Mensageiro/genética , Ratos , Ratos Wistar , Estreptozocina/farmacologia
2.
Nat Commun ; 11(1): 5099, 2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-33037202

RESUMO

Mutations in the skeletal muscle Ca2+ release channel, the type 1 ryanodine receptor (RYR1), cause malignant hyperthermia susceptibility (MHS) and a life-threatening sensitivity to heat, which is most severe in children. Mice with an MHS-associated mutation in Ryr1 (Y524S, YS) display lethal muscle contractures in response to heat. Here we show that the heat response in the YS mice is exacerbated by brown fat adaptive thermogenesis. In addition, the YS mice have more brown adipose tissue thermogenic capacity than their littermate controls. Blood lactate levels are elevated in both heat-sensitive MHS patients with RYR1 mutations and YS mice due to Ca2+ driven increases in muscle metabolism. Lactate increases brown adipogenesis in both mouse and human brown preadipocytes. This study suggests that simple lifestyle modifications such as avoiding extreme temperatures and maintaining thermoneutrality could decrease the risk of life-threatening responses to heat and exercise in individuals with RYR1 pathogenic variants.


Assuntos
Hipertermia Maligna/genética , Mutação , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Termogênese/fisiologia , Tecido Adiposo Marrom/metabolismo , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Feminino , Resposta ao Choque Térmico/genética , Resposta ao Choque Térmico/fisiologia , Humanos , Lactente , Lactatos/sangue , Masculino , Hipertermia Maligna/etiologia , Hipertermia Maligna/mortalidade , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Estudos Retrospectivos , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Termogênese/genética , Proteína Desacopladora 1/genética , Adulto Jovem
3.
Nature ; 585(7825): 420-425, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32879486

RESUMO

The opsin family of G-protein-coupled receptors are used as light detectors in animals. Opsin 5 (also known as neuropsin or OPN5) is a highly conserved opsin that is sensitive to visible violet light1,2. In mice, OPN5 is a known photoreceptor in the retina3 and skin4 but is also expressed in the hypothalamic preoptic area (POA)5. Here we describe a light-sensing pathway in which POA neurons that express Opn5 regulate thermogenesis in brown adipose tissue (BAT). We show that Opn5 is expressed in glutamatergic warm-sensing POA neurons that receive synaptic input from several thermoregulatory nuclei. We further show that Opn5 POA neurons project to BAT and decrease its activity under chemogenetic stimulation. Opn5-null mice show overactive BAT, increased body temperature, and exaggerated thermogenesis when cold-challenged. Moreover, violet photostimulation during cold exposure acutely suppresses BAT temperature in wild-type mice but not in Opn5-null mice. Direct measurements of intracellular cAMP ex vivo show that Opn5 POA neurons increase cAMP when stimulated with violet light. This analysis thus identifies a violet light-sensitive deep brain photoreceptor that normally suppresses BAT thermogenesis.


Assuntos
Cor , Luz , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Neurônios/efeitos da radiação , Opsinas/metabolismo , Área Pré-Óptica/citologia , Termogênese/efeitos da radiação , Tecido Adiposo Marrom/inervação , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/efeitos da radiação , Animais , Temperatura Corporal , Temperatura Baixa , AMP Cíclico/metabolismo , Feminino , Masculino , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Camundongos , Opsinas/deficiência , Opsinas/genética , Termogênese/genética
4.
Croat Med J ; 61(4): 346-353, 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32881433

RESUMO

AIM: To determine the changes in skin temperature and brown adipose tissue (BAT) activity throughout the estrous cycle as well as the regularity of the estrous cycle in mice. METHODS: We assessed the differences in the duration of the estrous cycle and its phases between 3- and 8-month-old female mice (n=18). Skin temperature and BAT activity were measured by infrared technology and compared with human menstrual cycle. RESULTS: Young and old female mice did not differ significantly in the estrous cycle length. However, young animals had longer diestrus and shorter proestrus phase. In contrast with women, mice showed age-dependent changes in body temperature and BAT activity during the estrus cycle. CONCLUSION: Establishing the pattern of temperature and BAT activity changes could be used to determine the estrous cycle phase before performing experiments without disturbing the animal. However, since the regulation of BAT activity during the estrous cycle was age-dependent, very complex, and varied significantly from women, further studies are needed to develop a non-invasive method for determining the phase of the estrous cycle.


Assuntos
Tecido Adiposo Marrom/metabolismo , Ciclo Estral/fisiologia , Temperatura Cutânea/fisiologia , Termografia/métodos , Animais , Animais de Laboratório , Estro/fisiologia , Feminino , Raios Infravermelhos , Camundongos , Camundongos Endogâmicos C57BL , Proestro/fisiologia
5.
Toxicol Lett ; 334: 27-35, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32956827

RESUMO

Methyl- and propyl- parabens are generally regarded as safe by the U.S Food and Drug Administration and as such are commonly used in personal care products. These parabens have been associated with increased white adipogenesis in vitro and methyl paraben also increased the white adipose mass of mice. Given brown adipose also plays a role in energy balance, we sought to evaluate whether the effects of methyl- and propyl- parabens on white adipocytes extended to brown adipocytes. We challenged white and brown pre-adipocytes at low doses of both parabens (up to 1 µM) during the differentiation process and examined adipogenesis with the ORO assay. The impact of each paraben on glucose uptake and lipolytic activity of adipocytes were measured with a fluorescent glucose analog and enzymatically, respectively. Methyl- and propyl- parabens increased adipogenesis of 3T3-L1 white adipocytes but not brown adipocytes. In white adipocytes, methyl paraben increased glucose uptake and both parabens reduced basal lipolysis. However, in brown adipocytes, parabens had no effect on basal lipolysis and instead attenuated isoproterenol induced lipolysis. These data indicate that methyl- and propyl- parabens target the differentiation and metabolic processes of multiple types of adipocytes in a cell autonomous manner.


Assuntos
Adipócitos/efeitos dos fármacos , Adipogenia/efeitos dos fármacos , Parabenos/toxicidade , Conservantes Farmacêuticos/toxicidade , Células 3T3-L1 , Adipócitos/metabolismo , Adipócitos/patologia , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/patologia , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/patologia , Animais , Diferenciação Celular/efeitos dos fármacos , Cosméticos , Glucose/metabolismo , Lipólise/efeitos dos fármacos , Camundongos
6.
Proc Natl Acad Sci U S A ; 117(36): 22080-22089, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32820071

RESUMO

Nonshivering thermogenesis occurs in brown adipose tissue to generate heat in response to cold ambient temperatures. Thioesterase superfamily member 1 (Them1) is transcriptionally up-regulated in brown adipose tissue upon exposure to the cold and suppresses thermogenesis in order to conserve energy reserves. It hydrolyzes long-chain fatty acyl-CoAs that are derived from lipid droplets, preventing their use as fuel for thermogenesis. In addition to its enzymatic domains, Them1 contains a C-terminal StAR-related lipid transfer (START) domain with unknown ligand or function. By complementary biophysical approaches, we show that the START domain binds to long-chain fatty acids, products of Them1's enzymatic reaction, as well as lysophosphatidylcholine (LPC), lipids shown to activate thermogenesis in brown adipocytes. Certain fatty acids stabilize the START domain and allosterically enhance Them1 catalysis of acyl-CoA, whereas 18:1 LPC destabilizes and inhibits activity, which we verify in cell culture. Additionally, we demonstrate that the START domain functions to localize Them1 near lipid droplets. These findings define the role of the START domain as a lipid sensor that allosterically regulates Them1 activity and spatially localizes it in proximity to the lipid droplet.


Assuntos
Ácidos Graxos/metabolismo , Lisofosfatidilcolinas/metabolismo , Palmitoil-CoA Hidrolase/química , Palmitoil-CoA Hidrolase/metabolismo , Acil Coenzima A/metabolismo , Tecido Adiposo Marrom/enzimologia , Tecido Adiposo Marrom/metabolismo , Regulação Alostérica , Ácidos Graxos/química , Humanos , Cinética , Gotículas Lipídicas/enzimologia , Gotículas Lipídicas/metabolismo , Lisofosfatidilcolinas/química , Palmitoil-CoA Hidrolase/genética , Domínios Proteicos
7.
Metabolism ; 111: 154341, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32810486

RESUMO

BACKGROUND: Biallelic loss of function variants in AGPAT2, encoding 1-acylglycerol-3-phosphate O-acyltransferase 2, cause congenital generalized lipodystrophy type 1, a disease characterized by near total loss of white adipose tissue and metabolic complications. Agpat2 deficient (Agpat2-/-) mice completely lacks both white and interscapular brown adipose tissue (iBAT). The objective of the present study was to characterize the effects of AGPAT2 deficiency in brown adipocyte differentiation. METHODS: Preadipocytes obtained from newborn (P0.5) Agpat2-/- and wild type mice iBAT were differentiated into brown adipocytes, compared by RNA microarray, RT-qPCR, High-Content Screening (HCS), western blotting and electron microscopy. RESULTS: 1) Differentiated Agpat2-/- brown adipocytes have fewer lipid-laden cells and lower abundance of Pparγ, Pparα, C/ebpα and Pgc1α, both at the mRNA and protein levels, compared those to wild type cells. Prmd16 levels were equivalent in both, Agpat2-/- and wild type, while Ucp1 was only induced in wild type cells, 2) These differences were not due to lower abundance of preadipocytes, 3) Differentiated Agpat2-/- brown adipocytes are enriched in the mRNA abundance of genes participating in interferon (IFN) type I response, whereas genes involved in mitochondrial homeostasis were decreased, 4) Mitochondria in differentiated Agpat2-/- brown adipocytes had altered morphology and lower mass and contacting sites with lipid droplets concomitant with lower levels of Mitofusin 2 and Perlipin 5. CONCLUSION: AGPAT2 is necessary for normal brown adipose differentiation. Its absence results in a lower proportion of lipid-laden cells, increased expression of interferon-stimulated genes (ISGs) and alterations in mitochondrial morphology, mass and fewer mitochondria to lipid droplets contacting sites in differentiated brown adipocytes.


Assuntos
Aciltransferases/metabolismo , Adipócitos Marrons/metabolismo , Adipogenia/fisiologia , Tecido Adiposo Marrom/metabolismo , Expressão Gênica/fisiologia , Interferon Tipo I/metabolismo , Mitocôndrias/metabolismo , Adipócitos Marrons/fisiologia , Tecido Adiposo Marrom/fisiologia , Animais , Diferenciação Celular/fisiologia , GTP Fosfo-Hidrolases/metabolismo , Homeostase/fisiologia , Camundongos , Mitocôndrias/fisiologia , RNA Mensageiro/metabolismo
9.
Nat Commun ; 11(1): 3347, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620768

RESUMO

A sharp increase in mitochondrial Ca2+ marks the activation of brown adipose tissue (BAT) thermogenesis, yet the mechanisms preventing Ca2+ deleterious effects are poorly understood. Here, we show that adrenergic stimulation of BAT activates a PKA-dependent mitochondrial Ca2+ extrusion via the mitochondrial Na+/Ca2+ exchanger, NCLX. Adrenergic stimulation of NCLX-null brown adipocytes (BA) induces a profound mitochondrial Ca2+ overload and impaired uncoupled respiration. Core body temperature, PET imaging of glucose uptake and VO2 measurements confirm a thermogenic defect in NCLX-null mice. We show that Ca2+ overload induced by adrenergic stimulation of NCLX-null BAT, triggers the mitochondrial permeability transition pore (mPTP) opening, leading to a remarkable mitochondrial swelling and cell death. Treatment with mPTP inhibitors rescue mitochondrial function and thermogenesis in NCLX-null BAT, while calcium overload persists. Our findings identify a key pathway through which BA evade apoptosis during adrenergic stimulation of uncoupling. NCLX deletion transforms the adrenergic pathway responsible for thermogenesis activation into a death pathway.


Assuntos
Adipócitos Marrons/patologia , Tecido Adiposo Marrom/metabolismo , Norepinefrina/metabolismo , Trocador de Sódio e Cálcio/metabolismo , Termogênese/fisiologia , Adipócitos Marrons/citologia , Adipócitos Marrons/efeitos dos fármacos , Tecido Adiposo Marrom/citologia , Adrenérgicos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Células Cultivadas , Temperatura Baixa/efeitos adversos , Ciclosporina/farmacologia , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Feminino , Microscopia Intravital , Masculino , Camundongos , Camundongos Knockout , Microscopia de Fluorescência , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/antagonistas & inibidores , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Cultura Primária de Células , Transdução de Sinais , Trocador de Sódio e Cálcio/genética , Termogênese/efeitos dos fármacos
10.
Mol Cell Biol ; 40(17)2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601106

RESUMO

Transcription factors C/EBPß and C/EBPδ are induced within hours after initiation of adipogenesis in culture. They directly promote the expression of master adipogenic transcription factors peroxisome proliferator-activated receptor γ (PPARγ) and C/EBPα and are required for adipogenesis in vivo However, the mechanism that controls the induction of C/EBPß and C/EBPδ remains elusive. We previously showed that histone methyltransferases MLL3/MLL4 and associated PTIP are required for the induction of PPARγ and C/EBPα during adipogenesis. Here, we show MLL3/MLL4/PTIP-associated protein PAGR1 (also known as PA1) cooperates with phosphorylated CREB and ligand-activated glucocorticoid receptor to directly control the induction of C/EBPß and C/EBPδ in the early phase of adipogenesis. Deletion of Pagr1 in white and brown preadipocytes prevents the induction of C/EBPß and C/EBPδ and leads to severe defects in adipogenesis. Adipogenesis defects in PAGR1-deficient cells can be rescued by the ectopic expression of C/EBPß or PPARγ. Finally, the deletion of Pagr1 in Myf5+ precursor cells impairs brown adipose tissue and muscle development. Thus, by controlling the induction of C/EBPß and C/EBPδ, PAGR1 plays a critical role in adipogenesis.


Assuntos
Adipogenia/fisiologia , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Histona-Lisina N-Metiltransferase/metabolismo , Células 3T3-L1 , Adipócitos/metabolismo , Tecido Adiposo Marrom/metabolismo , Animais , Diferenciação Celular/fisiologia , Histona Metiltransferases/metabolismo , Camundongos , Camundongos Knockout , PPAR gama/metabolismo , Ligação Proteica
11.
Cardiovasc Pathol ; 49: 107259, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32692664

RESUMO

Perivascular adipose tissue (PVAT) is a fat tissue deposit that encircles the vasculature. PVAT is traditionally known to protect the vasculature from external stimuli that could cause biological stress. In addition to the protective role of PVAT, it secretes certain biologically active substances known as adipokines that induce paracrine effects on proximate blood vessels. These adipokines influence vascular tones. There are different types of PVAT and they are phenotypically and functionally distinct. These are the white and brown PVATs. Under certain conditions, white PVAT could undergo phenotypic switch to attain a brown PVAT-like phenotype. This type of PVAT is referred to as Beige PVAT. The morphology of adipose tissue is influenced by species, age, and sex. These factors play significant roles in adipose tissue mass, functionality, paracrine activity, and predisposition to vascular diseases. The difficulty that is currently experienced in extrapolating animal models to human physiology could be traceable to these factors. Up till now, the involvement of PVAT in the development of vascular pathology is still not well understood. Brown and white PVAT contribute differently to vascular pathology. Thus, the PVAT could be a therapeutic target in curbing certain vascular diseases. In this review, knowledge would be updated on the multifaceted involvement of PVAT in vascular pathology and also explore its vascular therapeutic potential.


Assuntos
Tecido Adiposo Bege/patologia , Tecido Adiposo Marrom/patologia , Tecido Adiposo Branco/patologia , Artérias/patologia , Doenças Vasculares/patologia , Adipocinas/metabolismo , Tecido Adiposo Bege/efeitos dos fármacos , Tecido Adiposo Bege/metabolismo , Tecido Adiposo Bege/fisiopatologia , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/fisiopatologia , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/fisiopatologia , Adiposidade , Animais , Artérias/efeitos dos fármacos , Artérias/metabolismo , Artérias/fisiopatologia , Fármacos Cardiovasculares/uso terapêutico , Hemodinâmica , Humanos , Mediadores da Inflamação/metabolismo , Comunicação Parácrina , Transdução de Sinais , Doenças Vasculares/tratamento farmacológico , Doenças Vasculares/metabolismo , Doenças Vasculares/fisiopatologia
12.
Nat Commun ; 11(1): 3097, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32555194

RESUMO

Bone marrow adipose tissue (BMAT) comprises >10% of total adipose mass, yet unlike white or brown adipose tissues (WAT or BAT) its metabolic functions remain unclear. Herein, we address this critical gap in knowledge. Our transcriptomic analyses revealed that BMAT is distinct from WAT and BAT, with altered glucose metabolism and decreased insulin responsiveness. We therefore tested these functions in mice and humans using positron emission tomography-computed tomography (PET/CT) with 18F-fluorodeoxyglucose. This revealed that BMAT resists insulin- and cold-stimulated glucose uptake, while further in vivo studies showed that, compared to WAT, BMAT resists insulin-stimulated Akt phosphorylation. Thus, BMAT is functionally distinct from WAT and BAT. However, in humans basal glucose uptake in BMAT is greater than in axial bones or subcutaneous WAT and can be greater than that in skeletal muscle, underscoring the potential of BMAT to influence systemic glucose homeostasis. These PET/CT studies characterise BMAT function in vivo, establish new methods for BMAT analysis, and identify BMAT as a distinct, major adipose tissue subtype.


Assuntos
Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Medula Óssea/metabolismo , Glucose/metabolismo , Animais , Western Blotting , Feminino , Homeostase/fisiologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tomografia por Emissão de Pósitrons , Ratos , Esqueleto/metabolismo
14.
PLoS One ; 15(5): e0225488, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32453751

RESUMO

For (metabolic) research models using mice, singly housing is widely used for practical purposes to study e.g. energy balance regulation and derangements herein. Mouse (social) housing practices could however influence study results by modulating (metabolic) health outcomes. To study the effects of the social housing condition, we assessed parameters for energy balance regulation and proneness to (diet induced) obesity in male C57Bl/6J mice that were housed individually or socially (in pairs) directly after weaning, both at standard ambient temperature of 21°C. During adolescence, individually housed mice had reduced growth rate, while energy intake and energy expenditure were increased compared to socially housed counterparts. At 6 weeks of age, these mice had reduced lean body mass, but significantly higher white adipose tissue mass compared to socially housed mice, and higher UCP-1 mRNA expression in brown adipose tissue. During adulthood, body weight gain of individually housed animals exceeded that of socially housed mice, with elevations in both energy intake and expenditure. At 18 weeks of age, individually housed mice showed higher adiposity and higher mRNA expression of UCP-1 in inguinal white but not in brown adipose tissue. Exposure to an obesogenic diet starting at 6 weeks of age further amplified body weight gain and adipose tissue deposition and caused strong suppression of inguinal white adipose tissue mRNA UCP-1 expression. This study shows that post-weaning individual housing of male mice impairs adolescent growth and results in higher susceptibility to obesity in adulthood with putative roles for thermoregulation and/or affectiveness.


Assuntos
Metabolismo Energético , Abrigo para Animais , Obesidade/metabolismo , Proteína Desacopladora 1/metabolismo , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Animais , Composição Corporal , Regulação da Temperatura Corporal , Peso Corporal , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Ingestão de Energia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Desmame
15.
Metabolism ; 109: 154280, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32473155

RESUMO

OBJECTIVE: Obesity is recognized as the cause of multiple metabolic diseases and is rapidly increasing worldwide. As obesity is due to an imbalance in energy homeostasis, the promotion of energy consumption through browning of white adipose tissue (WAT) has emerged as a promising therapeutic strategy to counter the obesity epidemic. However, the molecular mechanisms of the browning process are not well understood. In this study, we investigated the effects of the GATA family of transcription factors on the browning process. METHODS: We used qPCR to analyze the expression of GATA family members during WAT browning. In order to investigate the function of GATA3 in the browning process, we used the lentivirus system for the ectopic expression and knockdown of GATA3. Western blot and real-time qPCR analyses revealed the regulation of thermogenic genes upon ectopic expression and knockdown of GATA3. Luciferase reporter assays, co-immunoprecipitation, and chromatin immunoprecipitation were performed to demonstrate that GATA3 interacts with proliferator-activated receptor-γ co-activator-1α (PGC-1α) to regulate the promoter activity of uncoupling protein-1 (UCP-1). Enhanced energy expenditure by GATA3 was confirmed using oxygen consumption assays, and the mitochondrial content was assessed using MitoTracker. Furthermore, we examined the in vivo effects of lentiviral GATA3 overexpression and knockdown in inguinal adipose tissue of mice. RESULTS: Gata3 expression levels were significantly elevated in the inguinal adipose tissue of mice exposed to cold conditions. Ectopic expression of GATA3 enhanced the expression of UCP-1 and thermogenic genes upon treatment with norepinephrine whereas GATA3 knockdown had the opposite effect. Luciferase reporter assays using the UCP-1 promoter region showed that UCP-1 expression was increased in a dose-dependent manner by GATA3 regardless of norepinephrine treatment. GATA3 was found to directly bind to the promoter region of UCP-1. Furthermore, our results indicated that GATA3 interacts with the transcriptional coactivator PGC-1α to increase the expression of UCP-1. Taken together, we demonstrate that GATA3 has an important role in enhancing energy expenditure by increasing the expression of thermogenic genes both in vitro and in vivo. CONCLUSION: GATA3 may represent a promising target for the prevention and treatment of obesity by regulating thermogenic capacity.


Assuntos
Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Fator de Transcrição GATA3/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Proteína Desacopladora 1/metabolismo , Animais , Temperatura Baixa , Metabolismo Energético , Fator de Transcrição GATA3/genética , Humanos , Camundongos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/fisiologia , Regiões Promotoras Genéticas , Termogênese/genética , Proteína Desacopladora 1/genética , Regulação para Cima
16.
Clin Nucl Med ; 45(8): 628-631, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32453085

RESUMO

Brown adipose tissue (BAT), which produces energy and is known to play a role as a hibernating gland, is sometimes visualized on F-FDG PET in children or in slender young adults in a cold environment. Because BAT is activated by catecholamines, FDG uptake in BAT is also observed in patients with pheochromocytoma or paraganglioma. We present the case of an elderly woman with remarkable FDG uptake in BAT. Activation of BAT by a ß3-adrenergic receptor agonist (mirabegron) prescribed for overactive bladder was suspected as the cause of the marked visualization of BAT in this patient.


Assuntos
Acetanilidas/efeitos adversos , Tecido Adiposo Marrom/diagnóstico por imagem , Agonistas Adrenérgicos/efeitos adversos , Fluordesoxiglucose F18/farmacocinética , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos/farmacocinética , Tiazóis/efeitos adversos , Acetanilidas/uso terapêutico , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Neoplasias das Glândulas Suprarrenais/diagnóstico por imagem , Agonistas Adrenérgicos/uso terapêutico , Idoso de 80 Anos ou mais , Feminino , Humanos , Feocromocitoma/diagnóstico por imagem , Tiazóis/uso terapêutico , Bexiga Urinária Hiperativa/tratamento farmacológico
17.
Nat Commun ; 11(1): 2306, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385399

RESUMO

During ß-adrenergic stimulation of brown adipose tissue (BAT), p38 phosphorylates the activating transcription factor 2 (ATF2) which then translocates to the nucleus to activate the expression of Ucp1 and Pgc-1α. The mechanisms underlying ATF2 target activation are unknown. Here we demonstrate that p62 (Sqstm1) binds to ATF2 to orchestrate activation of the Ucp1 enhancer and Pgc-1α promoter. P62Δ69-251 mice show reduced expression of Ucp1 and Pgc-1α with impaired ATF2 genomic binding. Modulation of Ucp1 and Pgc-1α expression through p62 regulation of ATF2 signaling is demonstrated in vitro and in vivo in p62Δ69-251 mice, global p62-/- and Ucp1-Cre p62flx/flx mice. BAT dysfunction resulting from p62 deficiency is manifest after birth and obesity subsequently develops despite normal food intake, intestinal nutrient absorption and locomotor activity. In summary, our data identify p62 as a master regulator of BAT function in that it controls the Ucp1 pathway through regulation of ATF2 genomic binding.


Assuntos
Fator 2 Ativador da Transcrição/metabolismo , Proteína Sequestossoma-1/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Adipogenia/fisiologia , Tecido Adiposo Marrom/diagnóstico por imagem , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/diagnóstico por imagem , Tecido Adiposo Branco/metabolismo , Animais , Núcleo Celular/metabolismo , Imagem por Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Ligação Proteica , Proteína Sequestossoma-1/genética , Proteína Desacopladora 1/metabolismo
18.
PLoS One ; 15(5): e0232084, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374735

RESUMO

Knowledge about the mouse brown adipose tissue (BAT) proteome can provide a deeper understanding of the function of mammalian BAT. Herein, a comprehensive analysis of interscapular BAT from C57BL/6J female mice was conducted by 2DLC and high-resolution mass spectrometry to construct a comprehensive proteome dataset of mouse BAT proteins. A total of 4949 nonredundant proteins were identified, and 4495 were quantified using the iBAQ method. According to the iBAQ values, the BAT proteome was divided into high-, middle- and low-abundance proteins. The functions of the high-abundance proteins were mainly related to glucose and fatty acid oxidation to produce heat for thermoregulation, while the functions of the middle- and low-abundance proteins were mainly related to protein synthesis and apoptosis, respectively. Additionally, 497 proteins were predicted to have signal peptides using SignalP4 software, and 75 were confirmed in previous studies. This study, for the first time, comprehensively profiled and functionally annotated the BAT proteome. This study will be helpful for future studies focused on biomarker identification and BAT molecular mechanisms.


Assuntos
Tecido Adiposo Marrom/metabolismo , Anotação de Sequência Molecular , Proteoma/metabolismo , Proteômica , Tecido Adiposo Marrom/química , Animais , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Bases de Dados de Proteínas , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Anotação de Sequência Molecular/métodos , Proteoma/análise , Proteômica/métodos , Espectrometria de Massas em Tandem
19.
Nat Commun ; 11(1): 2379, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32404872

RESUMO

Brown and beige fat share a remarkably similar transcriptional program that supports fuel oxidation and thermogenesis. The chromatin-remodeling machinery that governs genome accessibility and renders adipocytes poised for thermogenic activation remains elusive. Here we show that BAF60a, a subunit of the SWI/SNF chromatin-remodeling complexes, serves an indispensable role in cold-induced thermogenesis in brown fat. BAF60a maintains chromatin accessibility at PPARγ and EBF2 binding sites for key thermogenic genes. Surprisingly, fat-specific BAF60a inactivation triggers more pronounced cold-induced browning of inguinal white adipose tissue that is linked to induction of MC2R, a receptor for the pituitary hormone ACTH. Elevated MC2R expression sensitizes adipocytes and BAF60a-deficient adipose tissue to thermogenic activation in response to ACTH stimulation. These observations reveal an unexpected dichotomous role of BAF60a-mediated chromatin remodeling in transcriptional control of brown and beige gene programs and illustrate a pituitary-adipose signaling axis in the control of thermogenesis.


Assuntos
Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/deficiência , Temperatura Baixa , Adipócitos Marrons/efeitos dos fármacos , Adipócitos Marrons/metabolismo , Adipócitos Marrons/ultraestrutura , Tecido Adiposo Bege/metabolismo , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Branco/efeitos dos fármacos , Hormônio Adrenocorticotrópico/farmacologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Sítios de Ligação/genética , Células Cultivadas , Cromatina/genética , Proteínas Cromossômicas não Histona/genética , Expressão Gênica/efeitos dos fármacos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Termogênese/efeitos dos fármacos , Termogênese/genética
20.
Nat Commun ; 11(1): 2132, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358539

RESUMO

Brown adipose tissue (BAT) is known to secrete regulatory factors in response to thermogenic stimuli. Components of the BAT secretome may exert local effects that contribute to BAT recruitment and activation. Here, we found that a thermogenic stimulus leads to enhanced secretion of kininogen (Kng) by BAT, owing to induction of kininogen 2 (Kng2) gene expression. Noradrenergic, cAMP-mediated signals induce KNG2 expression and release in brown adipocytes. Conversely, the expression of kinin receptors, that are activated by the Kng products bradykinin and [Des-Arg9]-bradykinin, are repressed by thermogenic activation of BAT in vivo and of brown adipocytes in vitro. Loss-of-function models for Kng (the circulating-Kng-deficient BN/Ka rat) and bradykinin (pharmacological inhibition of kinin receptors, kinin receptor-null mice) signaling were coincident in showing abnormal overactivation of BAT. Studies in vitro indicated that Kng and bradykinin exert repressive effects on brown adipocyte thermogenic activity by interfering the PKA/p38 MAPK pathway of control of Ucp1 gene transcription, whereas impaired kinin receptor expression enhances it. Our findings identify the kallikrein-kinin system as a relevant component of BAT thermogenic regulation that provides auto-regulatory inhibitory signaling to BAT.


Assuntos
Tecido Adiposo Marrom/metabolismo , Calicreínas/metabolismo , Cininas/metabolismo , Animais , Bradicinina/genética , Bradicinina/metabolismo , Sistema Endócrino/metabolismo , Imunofluorescência , Calicreínas/genética , Cininogênios/genética , Cininogênios/metabolismo , Cininas/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
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