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1.
Adv Exp Med Biol ; 1207: 445-461, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32671767

RESUMO

The prevalence of obesity is increasing rapidly and is closely associated with a variety of metabolic diseases. Recent studies have suggested that autophagy is likely to play an important role in the development of obesity and may be related to insulin sensitivity. Autophagy may be involved in the browning of white adipose tissue and may also affect the metabolic balance of lipids. Autophagy can degrade cytoplasmic lipids by lipophagy in hepatocytes. Furthermore, Autophagy in hepatocytes helps prevent NAFLD. The study of autophagy in glucose metabolism is still in a very preliminary stage. Changes in autophagy activity play an important role in the development of insulin resistance in diabetes and many metabolic diseases. Therefore, it is still worth further exploration on the deeper mechanism of oxidative stress induction of insulin resistance to autophagy and whether there will be corresponding complications to the body.


Assuntos
Autofagia , Diabetes Mellitus , Obesidade , Tecido Adiposo Marrom , Tecido Adiposo Branco , Humanos , Resistência à Insulina
2.
PLoS One ; 15(6): e0234439, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530967

RESUMO

Disturbance of circadian rhythms underlies various metabolic diseases. Constant light exposure (LL) is known to disrupt both central and peripheral circadian rhythms. Here, we attempted to determine whether the effects of LL are different between various peripheral tissues and whether time-restricted feeding restores the circadian rhythms especially in white adipose tissue (WAT). Six-week-old mice were subjected to three feeding regimes: ad libitum feeding under light/dark phase (LD), ad libitum feeding under LL cycle, and restricted feeding at night-time under LL cycle with a normal chow. After 3 weeks, we compared body weight, food intake, plasma levels of lipids and glucose, and the expression patterns of the clock genes and the genes involved in lipid metabolism in the liver and WAT. The mice kept under LL with or without time-restricted feeding were 5.2% heavier (p<0.001, n = 16) than the mice kept under LD even though the food intakes of the two groups were the same. Food intake occurred mostly in the dark phase. LL disrupted this pattern, causing disruptions in circadian rhythms of plasma levels of triglycerides (TG) and glucose. Time-restricted feeding partially restored the rhythms. LL eliminated the circadian rhythms of the expression of the clock genes as well as most of the genes involved in lipid metabolism in both liver and WAT. More notably, LL markedly decreased not only the amplitude but also the average levels of the expression of the genes in the liver, but not in the WAT, suggesting that transcription in the liver is sensitive to constant light exposure. Time-restricted feeding restored the circadian rhythms of most of the genes to various degrees in both liver and WAT. In conclusion, LL disrupted the peripheral circadian rhythms more severely in liver than in WAT. Time-restricted feeding restored the circadian rhythms in both tissues.


Assuntos
Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Ritmo Circadiano/fisiologia , Jejum/fisiologia , Luz/efeitos adversos , Metabolismo dos Lipídeos/fisiologia , Tecido Adiposo Branco/metabolismo , Animais , Ritmo Circadiano/efeitos da radiação , Regulação da Expressão Gênica/efeitos da radiação , Metabolismo dos Lipídeos/efeitos da radiação , Fígado/metabolismo , Masculino , Camundongos , Modelos Animais , Fotoperíodo
3.
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
4.
Nat Commun ; 11(1): 2847, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32504036

RESUMO

The browning of white adipose tissue (WAT) has got much attention for its potential beneficial effects on metabolic disorders, however, the nutritional factors and neuronal signals involved remain largely unknown. We sought to investigate whether WAT browning is stimulated by leucine deprivation, and whether the amino acid sensor, general control non-derepressible 2 (GCN2), in amygdalar protein kinase C-δ (PKC-δ) neurons contributes to this regulation. Our results show that leucine deficiency can induce WAT browning, which is unlikely to be caused by food intake, but is largely blocked by PKC-δ neuronal inhibition and amygdalar GCN2 deletion. Furthermore, GCN2 knockdown in amygdalar PKC-δ neurons blocks WAT browning, which is reversed by over-expression of amino acid responsive gene activating transcription factor 4 (ATF4), and is mediated by the activities of amygdalar PKC-δ neurons and the sympathetic nervous system. Our data demonstrate that GCN2/ATF4 can regulate WAT browning in amygdalar PKC-δ neurons under leucine deprivation.


Assuntos
Fator 4 Ativador da Transcrição/metabolismo , Tecido Adiposo Branco/fisiologia , Tonsila do Cerebelo/fisiologia , Leucina/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Tecido Adiposo Marrom/fisiologia , Tecido Adiposo Branco/inervação , Tonsila do Cerebelo/citologia , Animais , Técnicas de Silenciamento de Genes , Lipólise/fisiologia , Masculino , Camundongos , Camundongos Knockout , Neurônios/metabolismo , Proteína Quinase C-delta/metabolismo , Proteínas Serina-Treonina Quinases/genética , Transdução de Sinais/fisiologia , Técnicas Estereotáxicas , Sistema Nervoso Simpático/fisiologia , Termogênese/fisiologia
5.
PLoS Genet ; 16(5): e1008823, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32453789

RESUMO

The development of type 2 diabetes mellitus (T2DM) depends on interactions between genetic and environmental factors, and a better understanding of gene-diet interactions in T2DM will be useful for disease prediction and prevention. Ascorbic acid has been proposed to reduce the risk of T2DM. However, the links between ascorbic acid and metabolic consequences are not fully understood. Here, we report that glucose transporter 10 (GLUT10) maintains intracellular levels of ascorbic acid to promote adipogenesis, white adipose tissue (WAT) development and protect mice from high-fat diet (HFD)-induced metabolic dysregulation. We found genetic polymorphisms in SLC2A10 locus are suggestively associated with a T2DM intermediate phenotype in non-diabetic Han Taiwanese. Additionally, mice carrying an orthologous human Glut10G128E variant (Glut10G128E mice) with compromised GLUT10 function have reduced adipogenesis, reduced WAT development and increased susceptibility to HFD-induced metabolic dysregulation. We further demonstrate that GLUT10 is highly expressed in preadipocytes, where it regulates intracellular ascorbic acid levels and adipogenesis. In this context, GLUT10 increases ascorbic acid-dependent DNA demethylation and the expression of key adipogenic genes, Cebpa and Pparg. Together, our data show GLUT10 regulates adipogenesis via ascorbic acid-dependent DNA demethylation to benefit proper WAT development and protect mice against HFD-induced metabolic dysregulation. Our findings suggest that SLC2A10 may be an important HFD-associated susceptibility locus for T2DM.


Assuntos
Tecido Adiposo Branco/metabolismo , Ácido Ascórbico/metabolismo , Metilação de DNA , Diabetes Mellitus Tipo 2/genética , Dieta Hiperlipídica/efeitos adversos , Proteínas Facilitadoras de Transporte de Glucose/genética , Células 3T3-L1 , Adipogenia , Adulto , Idoso , Animais , Proteínas Estimuladoras de Ligação a CCAAT/genética , Metilação de DNA/efeitos dos fármacos , Diabetes Mellitus Tipo 2/metabolismo , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Hemoglobina A Glicada/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Mutação , PPAR gama/genética
6.
PLoS One ; 15(5): e0232400, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32384084

RESUMO

Metabolic parameters ranging from circulating nutrient levels and substrate utilization to energy expenditure and thermogenesis are temporally modulated by the circadian timing system. During critical embryonic developmental periods, maternal over-nutrition could alter key elements in different tissues associated with the generation of circadian rhythmicity, compromising normal rhythmicity development. To address this issue, we determine whether maternal over-nutrition leads to alterations in the development of circadian rhythmicity at physiological and behavioral levels in the offspring. For this, female rabbits were fed a standard diet (SD) or high-fat and carbohydrate diet (HFCD) before mating and during gestation. Core body temperature and gross locomotor activity were continuously recorded in newborn rabbits, daily measurements of body weight and the amount of milk ingested was carried out. At the end of lactation, tissue samples, including brown adipose tissue (BAT) and white adipose tissue (WAT), were obtained for determining the expression of uncoupling protein-1 (UCP1) and cell death-inducing DNA fragmentation factor-like effector A (CIDEA) genes. HFCD pups exhibited conspicuous differences in the development of the daily rhythm of temperature and locomotor activity compared to the SD pups, including a significant increase in the daily mean core temperature, changes in the time when temperature or activity remains above the average, shifts in the acrophase, decrease in the duration and intensity of the anticipatory rise previous to nursing, and changes in frequency of the rhythms. HFCD pups exhibited a significant increase in BAT thermogenesis markers, and a decrease of these markers in WAT, indicating more heat generation by brown adipocytes and alterations in the browning process. These results indicate that maternal over-nutrition alters offspring homeostatic and chronostatic regulation at the physiological and behavioral levels. Further studies are needed to determine whether these alterations are associated with the changes in the organization of the circadian system of the progeny.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Ritmo Circadiano/fisiologia , Lactação/fisiologia , Locomoção/fisiologia , Tecido Adiposo Marrom/fisiopatologia , Tecido Adiposo Branco/fisiopatologia , Animais , Proteínas Reguladoras de Apoptose/genética , Regulação da Temperatura Corporal/genética , Ritmo Circadiano/genética , Modelos Animais de Doenças , Feminino , Expressão Gênica , Lactação/genética , Locomoção/genética , Fenômenos Fisiológicos da Nutrição Materna , Hipernutrição/complicações , Hipernutrição/genética , Hipernutrição/fisiopatologia , Gravidez , Complicações na Gravidez/genética , Complicações na Gravidez/fisiopatologia , Coelhos , Proteína Desacopladora 1/genética
7.
PLoS One ; 15(5): e0227720, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32407314

RESUMO

Numerous mutational studies have demonstrated that circadian clock proteins regulate behavior and metabolism. Nr1d1(Rev-erbα) is a key regulator of circadian gene expression and a pleiotropic regulator of skeletal muscle homeostasis and lipid metabolism. Loss of Rev-erbα expression induces muscular atrophy, high adiposity, and metabolic syndrome in mice. Here we show that, unlike knockout mice, Nr1d1 heterozygous mice are not susceptible to muscular atrophy and in fact paradoxically possess larger myofiber diameters and improved neuromuscular function, compared to wildtype mice. Heterozygous mice lacked dyslipidemia, a characteristic of Nr1d1 knockout mice and displayed increased whole-body fatty-acid oxidation during periods of inactivity (light cycle). Heterozygous mice also exhibited higher rates of glucose uptake when fasted, and had elevated basal rates of gluconeogenesis compared to wildtype and knockout littermates. Rev-erbα ablation suppressed glycolysis and fatty acid-oxidation in white-adipose tissue (WAT), whereas partial Rev-erbα loss, curiously stimulated these processes. Our investigations revealed that Rev-erbα dose-dependently regulates glucose metabolism and fatty acid oxidation in WAT and muscle.


Assuntos
Dislipidemias/genética , Músculo Esquelético/metabolismo , Atrofia Muscular/genética , Membro 1 do Grupo D da Subfamília 1 de Receptores Nucleares/genética , Tecido Adiposo Branco/metabolismo , Adiposidade/genética , Animais , Comportamento Animal/fisiologia , Relógios Circadianos/genética , Dislipidemias/metabolismo , Dislipidemias/patologia , Ácidos Graxos/metabolismo , Gluconeogênese/genética , Glucose/metabolismo , Heterozigoto , Humanos , Metabolismo dos Lipídeos/genética , Síndrome Metabólica/genética , Síndrome Metabólica/metabolismo , Síndrome Metabólica/patologia , Camundongos , Camundongos Knockout , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Miofibrilas/genética , Miofibrilas/metabolismo , Miofibrilas/patologia , Fotoperíodo
8.
Sci Total Environ ; 730: 138652, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32416500

RESUMO

Air pollution was becoming a global threat to the public health, which was primarily mediated by PM2.5 induced cardiovascular diseases and pulmonary diseases. Recently, observational epidemiologic studies proposed the link between PM2.5 and obesity. Consistently, the link was also supported by limited animal researches. However, the potential mechanism mediating the harmful effects of PM2.5 was still elusive. In this study, we applied the "real-ambient exposure" system to conduct the experiments, which was closer to the status of ambient air pollution compared with the method of intratracheal instillation and concentrated air particles (CAPs) exposure system. Nuclear factor E2-related factor 2 (Nrf2) was previously reported to protect against inflammation and oxidative stress when exposed to PM2.5. Here, we reported that Nrf2-/- mice developed overgrowth of adipose tissue after "real-ambient exposure" to PM2.5, compared to filtered air (FA) group. Consistently, compared to FA group, adipocytes from subcutaneous (sWAT) and gonadal (gWAT) white adipose tissue of Nrf2-/- mice exhibited enlarged cell size in PM2.5 exposure group. Furthermore, the levels of high-density lipoprotein (HDL) and low-density lipoprotein (LDL) in serum and liver of Nrf2-/- mice were also altered statistically in PM2.5 exposure group. Importantly, when the expression of lipogenic enzymes was analyzed, the levels of the related specific genes in adipose tissue and liver of Nrf2-/- mice were altered in PM2.5 exposure group. Interestingly, the key transcription factors modulating expression of lipogenic enzymes in liver of Nrf2-/- mice were also found altered in PM2.5 exposure group, such as peroxisome proliferator-activated receptor (PPARα, PPARγ). Taken together, our study mimicked the status of ambient air pollution, revealed new insights into the adverse effect of PM2.5 exposure, provided new link between air pollution and overgrowth of adipose tissue, and supported the vital role of Nrf2 in mediating the side effects of PM2.5.


Assuntos
Poluição do Ar , Tecido Adiposo Branco , Poluentes Atmosféricos , Animais , Camundongos , Fator 2 Relacionado a NF-E2 , Estresse Oxidativo , Material Particulado
9.
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
10.
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
11.
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
12.
Toxicol Appl Pharmacol ; 399: 115068, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32445754

RESUMO

Volatile organic compounds (VOCs), such as vinyl chloride (VC), can be directly toxic at high concentrations. However, we have shown that 'nontoxic' exposures to VC and its metabolite chloroethanol (CE) enhances experimental non-alcoholic fatty liver disease (NAFLD), suggesting an unpredicted interaction. Importantly, VOC exposure has been identified as a potential risk factor for the development of obesity and its sequelae in humans. As there is a known axis between adipose and hepatic tissue in NAFLD, the impact of CE on white adipose tissue (WAT) inflammation and lipolysis was investigated. Mice were administered CE (or vehicle) once, after 10 weeks of being fed high-fat or low-fat diet (LFD). CE significantly enhanced hepatic steatosis and inflammation caused by HFD. HFD significantly increased the size of epididymal fat pads, which was enhanced by CE. The relative size of adipocyte lipid droplets increased by HFD + CE, which was also correlated with increased expression of lipid-associated proteins (e.g., PLINs). CE also enhanced HFD-induced indices of WAT inflammation, and ER stress. Hepatic-derived circulating FGF21, a major modulator of WAT lipolysis, which is hypothesized to thereby regulate hepatic steatosis, was significantly increased by CE in animals fed HFD. Taken together these data support the hypothesis that environmental toxicant exposure can exacerbate the severity of NAFLD/NASH, involving the liver-adipose axis in this process. Specifically, CE enhances local inflammation and alters lipid metabolism and WAT-mediated hepatic steatosis due to changes in WAT lipolysis.


Assuntos
Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Cloreto de Vinil/toxicidade , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Dieta Hiperlipídica/efeitos adversos , Inflamação/induzido quimicamente , Inflamação/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/induzido quimicamente , Obesidade/metabolismo
13.
Nat Commun ; 11(1): 2303, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385276

RESUMO

White adipose tissue (WAT) expansion in obesity occurs through enlargement of preexisting adipocytes (hypertrophy) and through formation of new adipocytes (adipogenesis). Adipogenesis results in WAT hyperplasia, smaller adipocytes and a metabolically more favourable form of obesity. How obesogenic WAT hyperplasia is induced remains, however, poorly understood. Here, we show that the mechanosensitive cationic channel Piezo1 mediates diet-induced adipogenesis. Mice lacking Piezo1 in mature adipocytes demonstrated defective differentiation of preadipocyte into mature adipocytes when fed a high fat diet (HFD) resulting in larger adipocytes, increased WAT inflammation and reduced insulin sensitivity. Opening of Piezo1 in mature adipocytes causes the release of the adipogenic fibroblast growth factor 1 (FGF1), which induces adipocyte precursor differentiation through activation of the FGF-receptor-1. These data identify a central feed-back mechanism by which mature adipocytes control adipogenesis during the development of obesity and suggest Piezo1-mediated adipocyte mechano-signalling as a mechanism to modulate obesity and its metabolic consequences.


Assuntos
Adipócitos/metabolismo , Fator 1 de Crescimento de Fibroblastos/metabolismo , Canais Iônicos/metabolismo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Adipogenia/fisiologia , Tecido Adiposo Branco/metabolismo , Animais , Calorimetria , Células Cultivadas , Feminino , Fator 1 de Crescimento de Fibroblastos/genética , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Insulina/sangue , Interleucina-6/sangue , Canais Iônicos/genética , Masculino , Camundongos , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
14.
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
15.
PLoS One ; 15(5): e0233390, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32437400

RESUMO

Hypertrophy, associated with adipocyte dysfunction, causes increased pro-inflammatory adipokine, and abnormal glucose and lipid metabolism, leading to insulin resistance and obesity-related-health problems. By combining DNA microarray and genomic data analyses to predict DNA binding motifs, we identified the transcription factor Interferon Regulatory Factor 7 (IRF7) as a possible regulator of genes related to adipocyte hypertrophy. To investigate the role of IRF7 in adipocytes, we examined gene expression patterns in 3T3-L1 cells infected with a retrovirus carrying the IRF7 gene and found that enforced IRF7 expression induced the expression of monocyte chemoattractant protein-1 (MCP-1), a key initial adipokine in the chronic inflammation of obesity. CRISPR/Cas9 mediated-suppression of IRF7 significantly reduced MCP-1 mRNA. Luciferase assays, chromatin immunoprecipitation PCR analysis and gel shift assay showed that IRF7 transactivates the MCP-1 gene by binding to its proximal Interferon Stimulation Response Element (ISRE), a putative IRF7 binding motif. IRF7 knockout mice exhibited lower expression of MCP-1 in epidydimal white adipose tissue under high-fat feeding conditions, suggesting the transcription factor is physiologically important for inducing MCP-1. Taken together, our results suggest that IRF7 transactivates MCP-1 mRNA in adipocytes, and it may be involved in the adipose tissue inflammation associated with obesity.


Assuntos
Adipócitos/metabolismo , Quimiocina CCL2/genética , Fator Regulador 7 de Interferon/genética , Obesidade/genética , Células 3T3-L1 , Tecido Adiposo Branco/metabolismo , Animais , Quimiocina CCL2/metabolismo , Regulação da Expressão Gênica , Células HEK293 , Humanos , Fator Regulador 7 de Interferon/metabolismo , Camundongos , Camundongos Knockout , Obesidade/metabolismo , Regiões Promotoras Genéticas
16.
Gac Med Mex ; 156(2): 142-149, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32285854

RESUMO

Adipose tissue is an endocrine organ with high metabolic activity. Countless adipose tissue-secreted adipokines and lipokines, as well as peptides and lipids with biological activity have thus far been discovered. Both white and brown and beige adipose tissue are known to contribute to energy homeostasis and metabolic regulation. The purpose of this review is to report on the most recent findings related to adipose tissue according to its color and its relationship with metabolic alterations associated with obesity. After a review of the specialized literature, white, brown and beige adipocyte populations were identified to be able to coexist within the same structure, and to modify global metabolic state in physiological or pathological situations.


Assuntos
Tecido Adiposo Bege , Tecido Adiposo Marrom , Tecido Adiposo Branco , Cor
17.
Arch Biochem Biophys ; 686: 108364, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-32315653

RESUMO

Fucoxanthin (Fx), a major carotenoid found in brown seaweed, is known to show a unique and wide variety of biological activities. Upon absorption, Fx is metabolized to fucoxanthinol and amarouciaxanthin, and these metabolites mainly accumulate in visceral white adipose tissue (WAT). As seen in other carotenoids, Fx can quench singlet oxygen and scavenge a wide range of free radicals. The antioxidant activity is related to the neuroprotective, photoprotective, and hepatoprotective effects of Fx. Fx is also reported to show anti-cancer activity through the regulation of several biomolecules and signaling pathways that are involved in either cell cycle arrest, apoptosis, or metastasis suppression. Among the biological activities of Fx, anti-obesity is the most well-studied and most promising effect. This effect is primarily based on the upregulation of thermogenesis by uncoupling protein 1 expression and the increase in the metabolic rate induced by mitochondrial activation. In addition, Fx shows anti-diabetic effects by improving insulin resistance and promoting glucose utilization in skeletal muscle.


Assuntos
Suplementos Nutricionais/análise , Alga Marinha/química , Xantofilas/química , Xantofilas/metabolismo , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Animais , Fármacos Antiobesidade/química , Fármacos Antiobesidade/metabolismo , Antioxidantes/química , Antioxidantes/metabolismo , Descoberta de Drogas , Radicais Livres/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Hipoglicemiantes/química , Hipoglicemiantes/metabolismo , Resistência à Insulina , Fígado/metabolismo , Estrutura Molecular , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Depuradores/metabolismo , Oxigênio Singlete/metabolismo , Proteína Desacopladora 1/química , Proteína Desacopladora 1/metabolismo , Xantofilas/efeitos adversos , beta Caroteno/análogos & derivados , beta Caroteno/química
18.
Clin Sci (Lond) ; 134(7): 921-939, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32239178

RESUMO

Maternal obesity determines obesity and metabolic diseases in the offspring. The white adipose tissue (WAT) orchestrates metabolic pathways, and its dysfunction contributes to metabolic disorders in a sex-dependent manner. Here, we tested if sex differences influence the molecular mechanisms of metabolic programming of WAT in offspring of obese dams. To this end, maternal obesity was induced with high-fat diet (HFD) and the offspring were studied at an early phase [postnatal day 21 (P21)], a late phase (P70) and finally P120. In the early phase we found a sex-independent increase in WAT in offspring of obese dams using magnetic resonance imaging (MRI), which was more pronounced in females than males. While the adipocyte size increased in both sexes, the distribution of WAT differed in males and females. As mechanistic hints, we identified an inflammatory response in females and a senescence-associated reduction in the preadipocyte factor DLK in males. In the late phase, the obese body composition persisted in both sexes, with a partial reversal in females. Moreover, female offspring recovered completely from both the adipocyte hypertrophy and the inflammatory response. These findings were linked to a dysregulation of lipolytic, adipogenic and stemness-related markers as well as AMPKα and Akt signaling. Finally, the sex-dependent metabolic programming persisted with sex-specific differences in adipocyte size until P120. In conclusion, we do not only provide new insights into the molecular mechanisms of sex-dependent metabolic programming of WAT dysfunction, but also highlight the sex-dependent development of low- and high-grade pathogenic obesity.


Assuntos
Adipócitos Brancos/metabolismo , Adipogenia , Tecido Adiposo Branco/metabolismo , Adiposidade , Dieta Hiperlipídica , Metabolismo Energético , Obesidade Materna/metabolismo , Efeitos Tardios da Exposição Pré-Natal , Adipócitos Brancos/patologia , Adipogenia/genética , Tecido Adiposo Branco/patologia , Tecido Adiposo Branco/fisiopatologia , Adiposidade/genética , Fenômenos Fisiológicos da Nutrição Animal , Animais , Tamanho Celular , Modelos Animais de Doenças , Metabolismo Energético/genética , Feminino , Regulação da Expressão Gênica , Hipertrofia , Masculino , Fenômenos Fisiológicos da Nutrição Materna , Camundongos Endogâmicos C57BL , Estado Nutricional , Obesidade Materna/genética , Obesidade Materna/patologia , Obesidade Materna/fisiopatologia , Gravidez , Caracteres Sexuais , Fatores Sexuais , Transdução de Sinais , Fatores de Tempo
19.
Plast Reconstr Surg ; 145(5): 1183-1195, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32332538

RESUMO

BACKGROUND: Growing evidence has demonstrated that adipose-derived stem cell-derived extracellular vesicles enhance the survival of fat grafts and the browning of white adipose tissue. We evaluated whether supplementation with adipose-derived stem cell-derived extracellular vesicles promotes the survival and browning of fat grafts. METHODS: Extracellular vesicles derived from adipose-derived stem cells were injected into fat grafts of C57BL/6 mice once per week until postgraft week 12. The grafts were collected and weighed after postgraft weeks 2, 4, and 12. The histological morphology, neovascularization, and the proportion of M2 macrophages of grafts were evaluated. The ability of extracellular vesicles to promote macrophage polarization and catecholamine secretion was detected. Whether the inducement of browning adipose differentiation is extracellular vesicles or the paracrine effect of M2 macrophages polarized by extracellular vesicles was also verified. RESULTS: Grafts treated by extracellular vesicles derived from adipose-derived stem cells showed enhanced beige adipose regeneration with increased neovascularization, M2 macrophage proportion, and norepinephrine secretion at postgraft week 4. Increased retention and decreased fibrosis and necrosis were noted at postgraft week 12. The extracellular vesicles uptake by macrophages promoted M2 type polarization and catecholamine secretion while suppressing M1 type polarization. Of note, browning adipose differentiation with enhanced energy expenditure could be promoted only by the conditioned medium from extracellular vesicle-polarized M2 macrophages but not by extracellular vesicles themselves. CONCLUSIONS: Supplementation with extracellular vesicles derived from adipose-derived stem cells increases fat graft survival and browning by which extracellular vesicles-polarized M2 macrophages secrete catecholamines to promote beige adipose regeneration.


Assuntos
Tecido Adiposo Bege/fisiologia , Tecido Adiposo Branco/transplante , Vesículas Extracelulares/transplante , Sobrevivência de Enxerto/fisiologia , Células-Tronco/citologia , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/fisiologia , Adulto , Animais , Catecolaminas/metabolismo , Diferenciação Celular , Feminino , Humanos , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Regeneração , Adulto Jovem
20.
Nat Commun ; 11(1): 1642, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32242025

RESUMO

Increasing energy expenditure via induction of adipose tissue browning has become an appealing strategy to treat obesity and associated metabolic complications. Herein, we identify adipocyte-expressed apoptosis signal-regulating kinase 1 (ASK1) as regulator of adipose tissue browning. High fat diet-fed adipocyte-specific ASK1 knockout mice reveal increased UCP1 protein levels in inguinal adipose tissue concomitant with elevated energy expenditure, reduced obesity and ameliorated glucose tolerance compared to control littermates. In addition, ASK1-depletion blunts LPS-mediated downregulation of isoproterenol-induced UCP1 in subcutaneous fat both in vitro and in vivo. Conversely, adipocyte-specific ASK1 overexpression in chow-fed mice attenuates cold-induced UCP1 protein levels in inguinal fat. Mechanistically, ASK1 phosphorylates interferon regulatory factor 3 (IRF3) resulting in reduced Ucp1 expression. Taken together, our studies unravel a role of ASK1 in mediating the inhibitory effect of caloric surplus or LPS-treatment on adipose tissue browning. Adipocyte ASK1 might be a pharmacological target to combat obesity and associated morbidities.


Assuntos
Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , MAP Quinase Quinase Quinase 5/metabolismo , Obesidade/metabolismo , Animais , Metabolismo Energético , Feminino , Humanos , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/metabolismo , MAP Quinase Quinase Quinase 5/genética , Masculino , Camundongos , Camundongos Knockout , Obesidade/genética , Fosforilação , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo
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