RESUMO
Adipose tissue has been classified based on its morphology and function as white, brown, or beige/brite. It plays an essential role as a regulator of systemic metabolism through paracrine and endocrine signals. Recently, multiple adipocyte subtypes have been revealed using RNA sequencing technology, going beyond simply defined morphology but also by their cellular origin, adaptation to metabolic stress, and plasticity. Here, we performed an in-depth analysis of publicly available single-nuclei RNAseq from adipose tissue and utilized a workflow template to characterize adipocyte plasticity, heterogeneity, and secretome profiles. The reanalyzed dataset led to the identification of different subtypes of adipocytes including three subpopulations of thermogenic adipocytes, and provided a characterization of distinct transcriptional profiles along the adipocyte trajectory under thermogenic challenges. This study provides a useful resource for further investigations regarding mechanisms related to adipocyte plasticity and trans-differentiation.
Assuntos
Adipócitos Brancos/citologia , Tecido Adiposo Branco/citologia , Núcleo Celular/metabolismo , Plasticidade Celular , RNA-Seq , Termogênese/fisiologia , Animais , Camundongos , Temperatura , Proteína Desacopladora 1/metabolismoRESUMO
White adipose tissue hyperplasia has been shown to be crucial for handling excess energy in healthy ways. Though adipogenesis mechanisms have been underscored in vitro, we lack information on how tissue and systemic factors influence the differentiation of new adipocytes. While this could be studied in zebrafish, adipocyte identification currently relies on neutral lipid labeling, thus precluding access to cells in early stages of differentiation. Here we report the generation and analysis of a zebrafish line with the transgene fabp4a(-2.7):EGFPcaax. In vivo confocal microscopy of the pancreatic and abdominal visceral depots of transgenic larvae, revealed the presence of labeled mature adipocytes as well as immature cells in earlier stages of differentiation. Through co-labeling for blood vessels, we observed a close interaction of differentiating adipocytes with endothelial cells through cell protrusions. Finally, we implemented hyperspectral imaging and spectral phasor analysis in Nile Red-labeled transgenic larvae and revealed the lipid metabolic transition towards neutral lipid accumulation of differentiating adipocytes. Altogether our work presents the characterization of a novel adipocyte-specific label in zebrafish and uncovers previously unknown aspects of in vivo adipogenesis. This article has an associated First Person interview with the first author of the paper.
Assuntos
Adipócitos/fisiologia , Adipogenia/genética , Tecido Adiposo Branco/citologia , Diferenciação Celular/genética , Peixe-Zebra/embriologia , Adiponectina/metabolismo , Animais , Animais Geneticamente Modificados , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Linhagem Celular , Fator D do Complemento/metabolismo , Células Endoteliais/fisiologia , Proteínas de Ligação a Ácido Graxo/metabolismoRESUMO
BACKGROUND: Local fat accumulation is a health risk and this has raised interest in the development of aesthetic treatments, such as cryo-radiofrequency (CRF). OBJECTIVE: To evaluate the consequences of CRF in adipose tissue remodeling in a model system. MATERIALS AND METHODS: Lean and high-fat diet-induced obese mice were assessed 7 days after one CRF application; and lean mice were assessed 0, 3, 6 and 12 h after one application of CRF. Assessments included histology, DNA degradation, gene expression, ELISA of cytokines, serum analysis and neutrophil presence. RESULTS: Unchanged fat mass was found 7 days after CRF in obese and lean mice. However, lean mice showed smaller adipocyte size with areas resembling a browning process. TNF levels, apoptotic cells, and UCP-1 expression increased 7 days after CRF in inguinal adipose tissue of lean mice. Although no differences were found in fat mass, adipocyte size decreased just after CRF and this changed was maintained until 12 h, with cells resembling beige adipocytes. CONCLUSION: We suggest that CRF therapy is capable of inducing thermogenic adipocytes in lean mice.
Assuntos
Tecido Adiposo Marrom , Tecido Adiposo Branco , Crioterapia , Obesidade/terapia , Terapia por Radiofrequência , Adipócitos , Tecido Adiposo Marrom/citologia , Tecido Adiposo Branco/citologia , Animais , Camundongos , Camundongos Endogâmicos C57BL , TermogêneseRESUMO
The receptor activator of nuclear factor-κB (NF-κB) (RANK), its ligand (RANKL), and the decoy receptor osteoprotegerin (OPG) are a triad of proteins that regulate bone metabolism, and serum OPG is considered a biomarker for cardiovascular diseases and Type 2 diabetes; however, the implications of OPG in adipose tissue metabolism remains elusive. In this study, we investigate RANK-RANKL-OPG signaling in white adipose tissue browning. Histological analysis of osteoprotegerin knockout (OPG-/-) mice showed subcutaneous white adipose tissue (sWAT) browning, resistance for high-fat diet-induced weight gain, and preserved glucose metabolism compared with wild-type (WT) mice. Stromal vascular fraction (SVF) cells from sWAT of OPG-/- mice showed multilocular morphology and higher expression of brown adipocyte marker genes compared with those from the WT group. Infusion of RANKL induced browning and elevated respiratory rates in sWAT, along with increased whole body oxygen consumption in mice measured by indirect calorimetry. Subcutaneous WAT-derived SVF and 3T3-L1 cells, but not mature white adipocytes, differentiated into beige adipose tissue in the presence of RANKL. Moreover, SVF cells, even under white adipocyte differentiation, showed multilocular lipid droplet, lower lipid content, and increased expression of beige adipocyte markers with RANKL stimulation. In this study, we show for the first time the contribution of RANKL to increase energy expenditure by inducing beige adipocyte differentiation in preadipocytes.
Assuntos
Adipócitos Bege/metabolismo , Adipogenia/genética , Tecido Adiposo Branco/metabolismo , Obesidade/metabolismo , Osteoprotegerina/genética , Ligante RANK/metabolismo , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Células 3T3-L1 , Adipócitos Bege/citologia , Adipócitos Bege/ultraestrutura , Adipócitos Brancos/citologia , Adipócitos Brancos/metabolismo , Adipócitos Brancos/ultraestrutura , Tecido Adiposo Bege/citologia , Tecido Adiposo Bege/metabolismo , Tecido Adiposo Branco/citologia , Animais , Calorimetria Indireta , Dieta Hiperlipídica , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/genética , Gotículas Lipídicas/ultraestrutura , Camundongos , Camundongos Knockout , Osteoprotegerina/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/genética , Ligante RANK/farmacologia , Transdução de Sinais , Gordura Subcutânea/efeitos dos fármacos , Gordura Subcutânea/metabolismo , Aumento de Peso/efeitos dos fármacos , Aumento de Peso/genéticaRESUMO
OBJECTIVE: To use the combined presence of the elevated insulin resistance index in adipose tissue (Adipo-IR) and low values of adiponectin as a marker of dysfunctional adipose tissue, and to analyze its possible association with low values of high-density lipoprotein cholesterol (HDL-C) and small size of HDL particles. RESEARCH DESIGN AND METHODS: The analysis included 253 subjects with functional adipose tissue and 253 with dysfunctional adipose tissue, considering similar gender, age, and body mass index (BMI). Adipo-IR was considered when index values (free fatty acids × insulin concentrations) were ≥75th percentile. Low levels of adiponectin were considered when concentration in serum was <25th percentile (determined by ELISA). HDL size was estimated by a quantitative validated equation. Small HDL size was considered when values were <25th percentile. RESULTS: When comparing subjects with functional adipose tissue with those of dysfunctional adipose tissue, the latter had a higher prevalence of low HDL-C (51.4% vs. 64.0%; p = 0.004) and small HDL (56.9% vs. 67.6%; p = 0.009). Multivariate analysis indicated that independently from other metabolic risk factors, dysfunction of adipose tissue is significantly associated with low HDL-C (OR: 1.624 [CI 95%: 1.100-2.397]) and small HDL (OR: 1.462 [CI 95%: 1.000-2.139]). Adding BMI, waist circumference, and subcutaneous or visceral adipose tissue did not modify the association. CONCLUSIONS: Dysfunction of adipose tissue is associated with a 65 and 50% higher probability of having low HDL-C and small HDL. Identification of dysfunctional adipose tissue could be a useful tool in the clinical setting to prevent the cardiometabolic risk independently from adiposity.
Assuntos
Tecido Adiposo Branco , HDL-Colesterol , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/diagnóstico por imagem , Tecido Adiposo Branco/fisiopatologia , Índice de Massa Corporal , Peso Corporal/fisiologia , HDL-Colesterol/sangue , HDL-Colesterol/química , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade , Tamanho da Partícula , Circunferência da Cintura/fisiologiaRESUMO
Obesity is characterized by chronic and low-grade systemic inflammation, an increase of adipose tissue, hypertrophy, and hyperplasia of adipocytes. Adipose tissues can be classified into white, brown, beige and pink adipose tissues, which display different regulatory, morphological and functional characteristics of their adipocyte and immune cells. Brown and white adipocytes can play a key role not only in the control of energy homeostasis, or through the balance between energy storage and expenditure, but also by the modulation of immune and inflammatory responses. Therefore, brown and white adipocytes can orchestrate important immunological crosstalk that may deeply impact the tumor microenvironment and be crucial for cancer establishment and progression. Recent works have indicated that white adipose tissues can undergo a process called browning, in which an inducible brown adipocyte develops. In this review, we depict the mechanisms involved in the differential role of brown, white and pink adipocytes, highlighting their structural, morphological, regulatory and functional characteristics and correlation with cancer predisposition, establishment, and progression. We also discuss the impact of the increased adiposity in the inflammatory and immunological modulation. Moreover, we focused on the plasticity of adipocytes, describing the molecules produced and secreted by those cells, the modulation of the signaling pathways involved in the browning phenomena of white adipose tissue and its impact on inflammation and cancer.
Assuntos
Adiposidade/imunologia , Carcinogênese/imunologia , Inflamação/imunologia , Neoplasias/imunologia , Obesidade/imunologia , Adipócitos Marrons/imunologia , Adipócitos Marrons/metabolismo , Adipócitos Brancos/imunologia , Adipócitos Brancos/metabolismo , Tecido Adiposo Marrom/citologia , Tecido Adiposo Marrom/imunologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/imunologia , Tecido Adiposo Branco/metabolismo , Animais , Carcinogênese/patologia , Modelos Animais de Doenças , Progressão da Doença , Metabolismo Energético/imunologia , Humanos , Inflamação/metabolismo , Inflamação/patologia , Neoplasias/metabolismo , Neoplasias/patologia , Obesidade/complicações , Obesidade/metabolismo , Microambiente Tumoral/imunologiaRESUMO
Aerobic training induces adaptive responses in skeletal muscles and white adipose tissues, thus facilitating lipid utilization as energy substrates during a physical exercise session. However, the effects of training on cytokines levels and on transcription factors involved in lipid metabolism in muscle and different white adipose depots are still unclear; therefore, these were the aims of the present study. Nineteen adult male Wistar rats were randomly assigned to a trained group or a control, non-trained group. The 10-week training protocol consisted of running on a treadmill, during 1 hour per day, 5 days per week, at 75% of maximum aerobic speed. As expected, trained rats improved their aerobic performance and had augmented citrate synthase activity in the soleus, while the control rats did not. Although body weight was not different between groups, the adiposity index and white adipose depots (ie, epididymal and retroperitoneal) were reduced in trained rats. Training reduced serum concentration of insulin, but failed to change serum concentrations of glucose, triacylglycerol, total cholesterol, and nonesterified fatty acids. Training increased sterol regulatory element-binding protein-1c expression in the gastrocnemius and epididymal adipose tissue, and reduced peroxisome proliferator-activated receptor γ (PPARγ) expression in most of the tissues analyzed. The expression of PPARα and carnitine palmitoyltransferase 1 increased in the gastrocnemius and mesenteric adipose tissue but reduced in epididymal adipose tissue. Triacylglycerol content and tribbles 3 expression reduced in the gastrocnemius of trained rats. Tumor necrosis factor-α and interleukin-6 were increased in all adipose depots evaluated. Collectively, our data indicate that the 10-week aerobic training changed gene expression to improve muscle oxidative metabolism and facilitate lipid degradation in adipose tissues. Our data also highlight the existence of adaptive responses that are distinct between the skeletal muscle and white adipose tissue and between different adipose depots.
Assuntos
Tecido Adiposo Branco/metabolismo , Regulação da Expressão Gênica/fisiologia , Metabolismo dos Lipídeos/fisiologia , Músculo Esquelético/metabolismo , Condicionamento Físico Animal , Tecido Adiposo Branco/citologia , Animais , Masculino , Músculo Esquelético/citologia , Ratos , Ratos WistarRESUMO
This study investigated the effects of a grape pomace extract (GPE) rich in phenolic compounds on brown-like adipocyte induction and adiposity in spontaneously hypertensive (SHR) and control normotensive Wistar-Kyoto (WKY) rats fed a high-fat diet (HFD). HFD consumption for 10 weeks significantly increased epididymal white adipose tissue (eWAT) in WKY but not in SHR rats. Supplementation with GPE (300 mg/kg body weight/day) reduced adipocyte diameter and increased levels of proteins that participate in adipogenesis and angiogenesis, i.e., peroxisome-proliferator activated receptor gamma (PPARγ), vascular endothelial grow factor-A (VEGF-A) and its receptor 2 (VEGF-R2), and partially increased the uncoupling protein 1 (UCP-1) in WKY. In both strains, GPE attenuated adipose inflammation. In eWAT from SHR, GPE increased the expression of proteins involved in adipose tissue "browning," i.e., PPARγ-coactivator-1α (PGC-1α), PPARγ, PR domain containing 16 (PRDM16) and UCP-1. In primary cultures of SHR adipocytes, GPE-induced UCP-1 up-regulation was dependent on p38 and ERK activation. Accordingly, in 3T3-L1 adipocytes treated with palmitate, the addition of GPE (30 µM) activated the ß-adrenergic signaling cascade (PKA, AMPK, p38, ERK). This led to the associated up-regulation of proteins involved in mitochondrial biogenesis (PGC-1α, PPARγ, PRDM16 and UCP-1) and fatty acid oxidation (ATGL). These effects were similar to those exerted by (-)-epicatechin and quercetin, major phenolic compounds in GPE. Overall, in HFD-fed rats, supplementation with GPE promoted brown-like cell formation in eWAT and diminished adipose dysfunction. Thus, winemaking residues, rich in bioactive compounds, could be useful to mitigate the adverse effects of HFD-induced adipose dysfunction.
Assuntos
Adipócitos Bege/citologia , Tecido Adiposo Branco/citologia , Extratos Vegetais/farmacologia , Vitis/química , Células 3T3-L1 , Adipogenia , Tecido Adiposo , Tecido Adiposo Marrom/citologia , Animais , Peso Corporal , Diferenciação Celular , Dieta Hiperlipídica , Suplementos Nutricionais , Epididimo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Masculino , Camundongos , Estresse Oxidativo , PPAR gama/metabolismo , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição/metabolismo , Proteína Desacopladora 1/biossíntese , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
Induction of brown-like adipocytes (beige/brite cells) in white adipose tissue (WAT) suggests a new approach for preventing and treating obesity via induction of thermogenesis associated with uncoupling protein 1 (UCP1). However, whether diet-derived factors can directly induce browning of white adipocytes has not been well established. In addition, the underlying mechanism of induction of brown-like adipocytes by diet-derived factors has been unclear. Here, we demonstrate that artepillin C (ArtC), which is a typical Brazilian propolis-derived component, significantly induces brown-like adipocytes in murine C3H10T1/2 cells and primary inguinal WAT (iWAT)-derived adipocytes. This significant induction is due to activation of peroxisome proliferator-activated receptor γ and stabilization of PRD1-BF-1-RIZ1 homologous domain-containing protein-16 (PRDM16). Furthermore, the oral administration of ArtC (10 mg/kg) for 4 weeks significantly induced brown-like adipocytes accompanied by significant expression of UCP1 and PRDM16 proteins in iWAT of mice, and was independent of the ß3-adrenergic signaling pathway via the sympathetic nervous system. These findings may provide insight into browning of white adipocytes including the molecular mechanism mediated by dietary factors and demonstrate that ArtC has a novel biological function with regard to increasing energy expenditure by browning of white adipocytes.
Assuntos
Adipócitos Marrons/efeitos dos fármacos , Adipócitos Brancos/efeitos dos fármacos , Fármacos Antiobesidade/farmacologia , Metabolismo Energético/efeitos dos fármacos , Obesidade/prevenção & controle , Fenilpropionatos/farmacologia , Adipócitos Marrons/citologia , Adipócitos Marrons/metabolismo , Adipócitos Brancos/citologia , Adipócitos Brancos/metabolismo , Tecido Adiposo Marrom/citologia , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Administração Oral , Animais , Fármacos Antiobesidade/isolamento & purificação , Linhagem Celular , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Metabolismo Energético/genética , Regulação da Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/genética , Obesidade/metabolismo , Obesidade/patologia , PPAR gama/agonistas , PPAR gama/genética , PPAR gama/metabolismo , Fenilpropionatos/isolamento & purificação , Cultura Primária de Células , Própole/química , Transdução de Sinais , Termogênese/efeitos dos fármacos , Termogênese/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteína Desacopladora 1/agonistas , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismoRESUMO
White adipose tissue and brown adipose tissue play critical roles in controlling energy homeostasis and the development of obesity and diabetes. We isolated mouse white adipocytes from inguinal white fat tissues and brown adipocytes from interscapular brown fat tissues, and employed a variety of approaches, including immunofluorescent staining, quantitative real-time PCR, western blotting analysis, and differentiation assay, to characterize those adipocytes. Both white and brown adipocytes stained positively for CD44 and CD29, and lipid droplets were observed after the induction of adipogenesis. The Asc1 expression level in the white adipocytes was 2.5-fold higher than that in the brown adipocytes (P < 0.05), and the expression of Ucp1 in the white adipocytes was approximately 50% of that in the brown adipocytes (P < 0.05). The expression of α-tubulin in the brown adipocytes was approximately 70% of that in the white adipocytes. The brown adipocytes had a higher Cidea mRNA level (P < 0.05) and a lower Pparγ mRNA level (P < 0.05) than the white adipocytes. The results demonstrate that white and brown adipocytes have different gene expression signatures, and may represent two useful cell models to study the mechanisms involved in obesity.